[PATCH v4 0/3] Add touch screen support in at91 adc

[PATCH v4 0/3] Add touch screen support in at91 adc

[Josh Wu]

This patch series introduce multiple compatible string for different ip.
So remove some adc dt parameters as it already included in driver code.

It also touch screen support for at91 adc driver.
To enable touch screen you need add the touch screen related dt properties.

v3 --> v4:
  Seperate these 3 patches since the others are already in mainline.

Josh Wu (3):
  iio: at91: ADC start-up time calculation changed since at91sam9x5
  iio: at91: move the num_channels from DT to driver itself
  iio: at91: introduce touch screen support in iio adc driver

 .../devicetree/bindings/arm/atmel-adc.txt          |    8 +-
 arch/arm/mach-at91/include/mach/at91_adc.h         |   34 ++
 drivers/iio/adc/at91_adc.c                         |  453 ++++++++++++++++++--
 3 files changed, 456 insertions(+), 39 deletions(-)

-- 
1.7.9.5

[PATCH 1/3] iio: at91: ADC start-up time calculation changed since at91sam9x5

[Josh Wu]

Since in at91sam9x5, sama5d3x chip. the start up time calucation is changed.
This patch can choose different start up time calculation formula for different
chips.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/iio/adc/at91_adc.c |   53 ++++++++++++++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 0f16b55..cee04a4 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -40,6 +40,9 @@
 	(writel_relaxed(val, st->reg_base + reg))
 
 struct at91_adc_caps {
+	/* startup time calculate function */
+	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
+
 	struct at91_adc_reg_desc registers;
 };
 
@@ -434,6 +437,45 @@ ret:
 	return ret;
 }
 
+static u32 calc_startup_ticks_9260(u8 startup_time, u32 adc_clk_khz)
+{
+	/*
+	 * Number of ticks needed to cover the startup time of the ADC
+	 * as defined in the electrical characteristics of the board,
+	 * divided by 8. The formula thus is :
+	 *   Startup Time = (ticks + 1) * 8 / ADC Clock
+	 */
+	return round_up((startup_time * adc_clk_khz / 1000) - 1, 8) / 8;
+}
+
+static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
+{
+	/*
+	 * For sama5d3x and at91sam9x5, the formula changes to:
+	 * Startup Time = <lookup_table_value> / ADC Clock
+	 */
+	const int startup_lookup[] = {
+		0  , 8  , 16 , 24 ,
+		64 , 80 , 96 , 112,
+		512, 576, 640, 704,
+		768, 832, 896, 960
+		};
+	int i, size = ARRAY_SIZE(startup_lookup);
+	unsigned int ticks;
+
+	ticks = startup_time * adc_clk_khz / 1000;
+	for (i = 0; i < size; i++)
+		if (ticks < startup_lookup[i])
+			break;
+
+	ticks = i;
+	if (ticks == size)
+		/* Reach the end of lookup table */
+		ticks = size - 1;
+
+	return ticks;
+}
+
 static const struct of_device_id at91_adc_dt_ids[];
 
 static int at91_adc_probe_dt(struct at91_adc_state *st,
@@ -657,15 +699,9 @@ static int at91_adc_probe(struct platform_device *pdev)
 		ret = -EINVAL;
 		goto error_disable_adc_clk;
 	}
+	ticks = (*st->caps->calc_startup_ticks)(st->startup_time, adc_clk_khz);
 
 	/*
-	 * Number of ticks needed to cover the startup time of the ADC as
-	 * defined in the electrical characteristics of the board, divided by 8.
-	 * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
-	 */
-	ticks = round_up((st->startup_time * adc_clk_khz /
-			  1000) - 1, 8) / 8;
-	/*
 	 * a minimal Sample and Hold Time is necessary for the ADC to guarantee
 	 * the best converted final value between two channels selection
 	 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
@@ -742,6 +778,7 @@ static int at91_adc_remove(struct platform_device *pdev)
 
 #ifdef CONFIG_OF
 static struct at91_adc_caps at91sam9260_caps = {
+	.calc_startup_ticks = calc_startup_ticks_9260,
 	.registers = {
 		.channel_base = AT91_ADC_CHR(0),
 		.drdy_mask = AT91_ADC_DRDY,
@@ -753,6 +790,7 @@ static struct at91_adc_caps at91sam9260_caps = {
 };
 
 static struct at91_adc_caps at91sam9g45_caps = {
+	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
 	.registers = {
 		.channel_base = AT91_ADC_CHR(0),
 		.drdy_mask = AT91_ADC_DRDY,
@@ -764,6 +802,7 @@ static struct at91_adc_caps at91sam9g45_caps = {
 };
 
 static struct at91_adc_caps at91sam9x5_caps = {
+	.calc_startup_ticks = calc_startup_ticks_9x5,
 	.registers = {
 		.channel_base = AT91_ADC_CDR0_9X5,
 		.drdy_mask = AT91_ADC_SR_DRDY_9X5,
-- 
1.7.9.5

Re: [PATCH 1/3] iio: at91: ADC start-up time calculation changed since at91sam9x5

[Jonathan Cameron]

On 10/08/13 04:48, Josh Wu wrote:
> Since in at91sam9x5, sama5d3x chip. the start up time calucation is changed.
> This patch can choose different start up time calculation formula for different
> chips.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Applied to the togreg branch of iio.git

Thanks
> ---
>  drivers/iio/adc/at91_adc.c |   53 ++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 46 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index 0f16b55..cee04a4 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -40,6 +40,9 @@
>  	(writel_relaxed(val, st->reg_base + reg))
>  
>  struct at91_adc_caps {
> +	/* startup time calculate function */
> +	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
> +
>  	struct at91_adc_reg_desc registers;
>  };
>  
> @@ -434,6 +437,45 @@ ret:
>  	return ret;
>  }
>  
> +static u32 calc_startup_ticks_9260(u8 startup_time, u32 adc_clk_khz)
> +{
> +	/*
> +	 * Number of ticks needed to cover the startup time of the ADC
> +	 * as defined in the electrical characteristics of the board,
> +	 * divided by 8. The formula thus is :
> +	 *   Startup Time = (ticks + 1) * 8 / ADC Clock
> +	 */
> +	return round_up((startup_time * adc_clk_khz / 1000) - 1, 8) / 8;
> +}
> +
> +static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
> +{
> +	/*
> +	 * For sama5d3x and at91sam9x5, the formula changes to:
> +	 * Startup Time = <lookup_table_value> / ADC Clock
> +	 */
> +	const int startup_lookup[] = {
> +		0  , 8  , 16 , 24 ,
> +		64 , 80 , 96 , 112,
> +		512, 576, 640, 704,
> +		768, 832, 896, 960
> +		};
> +	int i, size = ARRAY_SIZE(startup_lookup);
> +	unsigned int ticks;
> +
> +	ticks = startup_time * adc_clk_khz / 1000;
> +	for (i = 0; i < size; i++)
> +		if (ticks < startup_lookup[i])
> +			break;
> +
> +	ticks = i;
> +	if (ticks == size)
> +		/* Reach the end of lookup table */
> +		ticks = size - 1;
> +
> +	return ticks;
> +}
> +
>  static const struct of_device_id at91_adc_dt_ids[];
>  
>  static int at91_adc_probe_dt(struct at91_adc_state *st,
> @@ -657,15 +699,9 @@ static int at91_adc_probe(struct platform_device *pdev)
>  		ret = -EINVAL;
>  		goto error_disable_adc_clk;
>  	}
> +	ticks = (*st->caps->calc_startup_ticks)(st->startup_time, adc_clk_khz);
>  
>  	/*
> -	 * Number of ticks needed to cover the startup time of the ADC as
> -	 * defined in the electrical characteristics of the board, divided by 8.
> -	 * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
> -	 */
> -	ticks = round_up((st->startup_time * adc_clk_khz /
> -			  1000) - 1, 8) / 8;
> -	/*
>  	 * a minimal Sample and Hold Time is necessary for the ADC to guarantee
>  	 * the best converted final value between two channels selection
>  	 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
> @@ -742,6 +778,7 @@ static int at91_adc_remove(struct platform_device *pdev)
>  
>  #ifdef CONFIG_OF
>  static struct at91_adc_caps at91sam9260_caps = {
> +	.calc_startup_ticks = calc_startup_ticks_9260,
>  	.registers = {
>  		.channel_base = AT91_ADC_CHR(0),
>  		.drdy_mask = AT91_ADC_DRDY,
> @@ -753,6 +790,7 @@ static struct at91_adc_caps at91sam9260_caps = {
>  };
>  
>  static struct at91_adc_caps at91sam9g45_caps = {
> +	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
>  	.registers = {
>  		.channel_base = AT91_ADC_CHR(0),
>  		.drdy_mask = AT91_ADC_DRDY,
> @@ -764,6 +802,7 @@ static struct at91_adc_caps at91sam9g45_caps = {
>  };
>  
>  static struct at91_adc_caps at91sam9x5_caps = {
> +	.calc_startup_ticks = calc_startup_ticks_9x5,
>  	.registers = {
>  		.channel_base = AT91_ADC_CDR0_9X5,
>  		.drdy_mask = AT91_ADC_SR_DRDY_9X5,
> 

[PATCH 2/3] iio: at91: move the num_channels from DT to driver itself

[Josh Wu]

CC: devicetree@vger.kernel.org
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 .../devicetree/bindings/arm/atmel-adc.txt          |    1 -
 drivers/iio/adc/at91_adc.c                         |   12 +++++-------
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/atmel-adc.txt b/Documentation/devicetree/bindings/arm/atmel-adc.txt
index 723c205..0e65e01 100644
--- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
+++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
@@ -7,7 +7,6 @@ Required properties:
   - interrupts: Should contain the IRQ line for the ADC
   - atmel,adc-channels-used: Bitmask of the channels muxed and enable for this
     device
-  - atmel,adc-num-channels: Number of channels available in the ADC
   - atmel,adc-startup-time: Startup Time of the ADC in microseconds as
     defined in the datasheet
   - atmel,adc-vref: Reference voltage in millivolts for the conversions
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index cee04a4..22cf61d2 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -43,6 +43,7 @@ struct at91_adc_caps {
 	/* startup time calculate function */
 	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
 
+	u8	num_channels;
 	struct at91_adc_reg_desc registers;
 };
 
@@ -502,13 +503,6 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
 	}
 	st->channels_mask = prop;
 
-	if (of_property_read_u32(node, "atmel,adc-num-channels", &prop)) {
-		dev_err(&idev->dev, "Missing adc-num-channels property in the DT.\n");
-		ret = -EINVAL;
-		goto error_ret;
-	}
-	st->num_channels = prop;
-
 	st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode");
 
 	if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
@@ -534,6 +528,7 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
 		goto error_ret;
 
 	st->registers = &st->caps->registers;
+	st->num_channels = st->caps->num_channels;
 	st->trigger_number = of_get_child_count(node);
 	st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
 					sizeof(struct at91_adc_trigger),
@@ -779,6 +774,7 @@ static int at91_adc_remove(struct platform_device *pdev)
 #ifdef CONFIG_OF
 static struct at91_adc_caps at91sam9260_caps = {
 	.calc_startup_ticks = calc_startup_ticks_9260,
+	.num_channels = 4,
 	.registers = {
 		.channel_base = AT91_ADC_CHR(0),
 		.drdy_mask = AT91_ADC_DRDY,
@@ -791,6 +787,7 @@ static struct at91_adc_caps at91sam9260_caps = {
 
 static struct at91_adc_caps at91sam9g45_caps = {
 	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
+	.num_channels = 8,
 	.registers = {
 		.channel_base = AT91_ADC_CHR(0),
 		.drdy_mask = AT91_ADC_DRDY,
@@ -803,6 +800,7 @@ static struct at91_adc_caps at91sam9g45_caps = {
 
 static struct at91_adc_caps at91sam9x5_caps = {
 	.calc_startup_ticks = calc_startup_ticks_9x5,
+	.num_channels = 12,
 	.registers = {
 		.channel_base = AT91_ADC_CDR0_9X5,
 		.drdy_mask = AT91_ADC_SR_DRDY_9X5,
-- 
1.7.9.5

Re: [PATCH 2/3] iio: at91: move the num_channels from DT to driver itself

[Jonathan Cameron]

On 10/08/13 04:48, Josh Wu wrote:
> CC: devicetree@vger.kernel.org
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Applied to the togreg branch of iio.git

Thanks,

> ---
>  .../devicetree/bindings/arm/atmel-adc.txt          |    1 -
>  drivers/iio/adc/at91_adc.c                         |   12 +++++-------
>  2 files changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/atmel-adc.txt b/Documentation/devicetree/bindings/arm/atmel-adc.txt
> index 723c205..0e65e01 100644
> --- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
> +++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
> @@ -7,7 +7,6 @@ Required properties:
>    - interrupts: Should contain the IRQ line for the ADC
>    - atmel,adc-channels-used: Bitmask of the channels muxed and enable for this
>      device
> -  - atmel,adc-num-channels: Number of channels available in the ADC
>    - atmel,adc-startup-time: Startup Time of the ADC in microseconds as
>      defined in the datasheet
>    - atmel,adc-vref: Reference voltage in millivolts for the conversions
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index cee04a4..22cf61d2 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -43,6 +43,7 @@ struct at91_adc_caps {
>  	/* startup time calculate function */
>  	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
>  
> +	u8	num_channels;
>  	struct at91_adc_reg_desc registers;
>  };
>  
> @@ -502,13 +503,6 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
>  	}
>  	st->channels_mask = prop;
>  
> -	if (of_property_read_u32(node, "atmel,adc-num-channels", &prop)) {
> -		dev_err(&idev->dev, "Missing adc-num-channels property in the DT.\n");
> -		ret = -EINVAL;
> -		goto error_ret;
> -	}
> -	st->num_channels = prop;
> -
>  	st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode");
>  
>  	if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
> @@ -534,6 +528,7 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
>  		goto error_ret;
>  
>  	st->registers = &st->caps->registers;
> +	st->num_channels = st->caps->num_channels;
>  	st->trigger_number = of_get_child_count(node);
>  	st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
>  					sizeof(struct at91_adc_trigger),
> @@ -779,6 +774,7 @@ static int at91_adc_remove(struct platform_device *pdev)
>  #ifdef CONFIG_OF
>  static struct at91_adc_caps at91sam9260_caps = {
>  	.calc_startup_ticks = calc_startup_ticks_9260,
> +	.num_channels = 4,
>  	.registers = {
>  		.channel_base = AT91_ADC_CHR(0),
>  		.drdy_mask = AT91_ADC_DRDY,
> @@ -791,6 +787,7 @@ static struct at91_adc_caps at91sam9260_caps = {
>  
>  static struct at91_adc_caps at91sam9g45_caps = {
>  	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
> +	.num_channels = 8,
>  	.registers = {
>  		.channel_base = AT91_ADC_CHR(0),
>  		.drdy_mask = AT91_ADC_DRDY,
> @@ -803,6 +800,7 @@ static struct at91_adc_caps at91sam9g45_caps = {
>  
>  static struct at91_adc_caps at91sam9x5_caps = {
>  	.calc_startup_ticks = calc_startup_ticks_9x5,
> +	.num_channels = 12,
>  	.registers = {
>  		.channel_base = AT91_ADC_CDR0_9X5,
>  		.drdy_mask = AT91_ADC_SR_DRDY_9X5,
> 

[PATCH 3/3] iio: at91: introduce touch screen support in iio adc driver

[Josh Wu]

AT91 ADC hardware integrate touch screen support. So this patch add touch
screen support for at91 adc iio driver.
To enable touch screen support in adc, you need to add the dt parameters:
  1. which type of touch are used? (4 or 5 wires), sample period time.
  2. correct pressure detect threshold value.

In the meantime, since touch screen will use a interal period trigger of adc,
so it is conflict to other hardware triggers. Driver will disable the hardware
trigger support if touch screen is enabled.

This driver has been tested in AT91SAM9X5-EK and SAMA5D3x-EK.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
CC: devicetree@vger.kernel.org
---
 .../devicetree/bindings/arm/atmel-adc.txt          |    7 +
 arch/arm/mach-at91/include/mach/at91_adc.h         |   34 ++
 drivers/iio/adc/at91_adc.c                         |  388 ++++++++++++++++++--
 3 files changed, 405 insertions(+), 24 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/atmel-adc.txt b/Documentation/devicetree/bindings/arm/atmel-adc.txt
index 0e65e01..d106146 100644
--- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
+++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
@@ -23,6 +23,13 @@ Optional properties:
 		       resolution will be used.
   - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
   - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
+  - atmel,adc-ts-wires: Number of touch screen wires. Should be 4 or 5. If this
+                        value is set, then adc driver will enable touch screen
+                        support.
+    NOTE: when adc touch screen enabled, the adc hardware trigger will be
+          disabled. Since touch screen will occupied the trigger register.
+  - atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
+                                     make touch detect more precision.
  
 Optional trigger Nodes:
   - Required properties:
diff --git a/arch/arm/mach-at91/include/mach/at91_adc.h b/arch/arm/mach-at91/include/mach/at91_adc.h
index 048a57f..c287307 100644
--- a/arch/arm/mach-at91/include/mach/at91_adc.h
+++ b/arch/arm/mach-at91/include/mach/at91_adc.h
@@ -60,14 +60,48 @@
 #define AT91_ADC_IER		0x24		/* Interrupt Enable Register */
 #define AT91_ADC_IDR		0x28		/* Interrupt Disable Register */
 #define AT91_ADC_IMR		0x2C		/* Interrupt Mask Register */
+#define		AT91_ADC_IER_PEN	(1 << 29)
+#define		AT91_ADC_IER_NOPEN	(1 << 30)
+#define		AT91_ADC_IER_XRDY	(1 << 20)
+#define		AT91_ADC_IER_YRDY	(1 << 21)
+#define		AT91_ADC_IER_PRDY	(1 << 22)
+#define		AT91_ADC_ISR_PENS	(1 << 31)
 
 #define AT91_ADC_CHR(n)		(0x30 + ((n) * 4))	/* Channel Data Register N */
 #define		AT91_ADC_DATA		(0x3ff)
 
 #define AT91_ADC_CDR0_9X5	(0x50)			/* Channel Data Register 0 for 9X5 */
 
+#define AT91_ADC_ACR		0x94	/* Analog Control Register */
+#define		AT91_ADC_ACR_PENDETSENS	(0x3 << 0)	/* pull-up resistor */
+
+#define AT91_ADC_TSMR		0xB0
+#define		AT91_ADC_TSMR_TSMODE	(3 << 0)	/* Touch Screen Mode */
+#define			AT91_ADC_TSMR_TSMODE_NONE		(0 << 0)
+#define			AT91_ADC_TSMR_TSMODE_4WIRE_NO_PRESS	(1 << 0)
+#define			AT91_ADC_TSMR_TSMODE_4WIRE_PRESS	(2 << 0)
+#define			AT91_ADC_TSMR_TSMODE_5WIRE		(3 << 0)
+#define		AT91_ADC_TSMR_TSAV	(3 << 4)	/* Averages samples */
+#define			AT91_ADC_TSMR_TSAV_(x)		((x) << 4)
+#define		AT91_ADC_TSMR_SCTIM	(0x0f << 16)	/* Switch closure time */
+#define		AT91_ADC_TSMR_PENDBC	(0x0f << 28)	/* Pen Debounce time */
+#define			AT91_ADC_TSMR_PENDBC_(x)	((x) << 28)
+#define		AT91_ADC_TSMR_NOTSDMA	(1 << 22)	/* No Touchscreen DMA */
+#define		AT91_ADC_TSMR_PENDET_DIS	(0 << 24)	/* Pen contact detection disable */
+#define		AT91_ADC_TSMR_PENDET_ENA	(1 << 24)	/* Pen contact detection enable */
+
+#define AT91_ADC_TSXPOSR	0xB4
+#define AT91_ADC_TSYPOSR	0xB8
+#define AT91_ADC_TSPRESSR	0xBC
+
 #define AT91_ADC_TRGR_9260	AT91_ADC_MR
 #define AT91_ADC_TRGR_9G45	0x08
 #define AT91_ADC_TRGR_9X5	0xC0
 
+/* Trigger Register bit field */
+#define		AT91_ADC_TRGR_TRGPER	(0xffff << 16)
+#define			AT91_ADC_TRGR_TRGPER_(x)	((x) << 16)
+#define		AT91_ADC_TRGR_TRGMOD	(0x7 << 0)
+#define			AT91_ADC_TRGR_MOD_PERIOD_TRIG	(5 << 0)
+
 #endif
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 22cf61d2..68ddd7f 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -11,6 +11,7 @@
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
+#include <linux/input.h>
 #include <linux/interrupt.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
@@ -39,7 +40,23 @@
 #define at91_adc_writel(st, reg, val) \
 	(writel_relaxed(val, st->reg_base + reg))
 
+#define DRIVER_NAME		"at91_adc"
+#define MAX_POS_BITS		12
+
+#define TOUCH_SAMPLE_PERIOD_US		2000	/* 2ms */
+#define TOUCH_PEN_DETECT_DEBOUNCE_US	200
+
 struct at91_adc_caps {
+	bool	has_ts;		/* Support touch screen */
+	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
+	/*
+	 * Numbers of sampling data will be averaged. Can be 0~3.
+	 * Hardware can average (2 ^ ts_filter_average) sample data.
+	 */
+	u8	ts_filter_average;
+	/* Pen Detection input pull-up resistor, can be 0~3 */
+	u8	ts_pen_detect_sensitivity;
+
 	/* startup time calculate function */
 	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
 
@@ -47,6 +64,12 @@ struct at91_adc_caps {
 	struct at91_adc_reg_desc registers;
 };
 
+enum atmel_adc_ts_type {
+	ATMEL_ADC_TOUCHSCREEN_NONE = 0,
+	ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
+	ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
+};
+
 struct at91_adc_state {
 	struct clk		*adc_clk;
 	u16			*buffer;
@@ -71,6 +94,26 @@ struct at91_adc_state {
 	bool			low_res;	/* the resolution corresponds to the lowest one */
 	wait_queue_head_t	wq_data_avail;
 	struct at91_adc_caps	*caps;
+
+	/*
+	 * Following ADC channels are shared by touchscreen:
+	 *
+	 * CH0 -- Touch screen XP/UL
+	 * CH1 -- Touch screen XM/UR
+	 * CH2 -- Touch screen YP/LL
+	 * CH3 -- Touch screen YM/Sense
+	 * CH4 -- Touch screen LR(5-wire only)
+	 *
+	 * The bitfields below represents the reserved channel in the
+	 * touchscreen mode.
+	 */
+#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 0)
+#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 0)
+	enum atmel_adc_ts_type	touchscreen_type;
+	struct input_dev	*ts_input;
+
+	u16			ts_sample_period_val;
+	u32			ts_pressure_threshold;
 };
 
 static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
@@ -105,14 +148,10 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
+/* Handler for classic adc channel eoc trigger */
+void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
 {
-	struct iio_dev *idev = private;
 	struct at91_adc_state *st = iio_priv(idev);
-	u32 status = at91_adc_readl(st, st->registers->status_register);
-
-	if (!(status & st->registers->drdy_mask))
-		return IRQ_HANDLED;
 
 	if (iio_buffer_enabled(idev)) {
 		disable_irq_nosync(irq);
@@ -122,6 +161,115 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
 		st->done = true;
 		wake_up_interruptible(&st->wq_data_avail);
 	}
+}
+
+static int at91_ts_sample(struct at91_adc_state *st)
+{
+	unsigned int xscale, yscale, reg, z1, z2;
+	unsigned int x, y, pres, xpos, ypos;
+	unsigned int rxp = 1;
+	unsigned int factor = 1000;
+	struct iio_dev *idev = iio_priv_to_dev(st);
+
+	unsigned int xyz_mask_bits = st->res;
+	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
+
+	/* calculate position */
+	/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
+	reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
+	xpos = reg & xyz_mask;
+	x = (xpos << MAX_POS_BITS) - xpos;
+	xscale = (reg >> 16) & xyz_mask;
+	if (xscale == 0) {
+		dev_err(&idev->dev, "Error: xscale == 0!\n");
+		return -1;
+	}
+	x /= xscale;
+
+	/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
+	reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
+	ypos = reg & xyz_mask;
+	y = (ypos << MAX_POS_BITS) - ypos;
+	yscale = (reg >> 16) & xyz_mask;
+	if (yscale == 0) {
+		dev_err(&idev->dev, "Error: yscale == 0!\n");
+		return -1;
+	}
+	y /= yscale;
+
+	/* calculate the pressure */
+	reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
+	z1 = reg & xyz_mask;
+	z2 = (reg >> 16) & xyz_mask;
+
+	if (z1 != 0)
+		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
+			/ factor;
+	else
+		pres = st->ts_pressure_threshold;	/* no pen contacted */
+
+	dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
+				xpos, xscale, ypos, yscale, z1, z2, pres);
+
+	if (pres < st->ts_pressure_threshold) {
+		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
+					x, y, pres / factor);
+		input_report_abs(st->ts_input, ABS_X, x);
+		input_report_abs(st->ts_input, ABS_Y, y);
+		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
+		input_report_key(st->ts_input, BTN_TOUCH, 1);
+		input_sync(st->ts_input);
+	} else {
+		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
+	}
+
+	return 0;
+}
+
+static irqreturn_t at91_adc_interrupt(int irq, void *private)
+{
+	struct iio_dev *idev = private;
+	struct at91_adc_state *st = iio_priv(idev);
+	u32 status = at91_adc_readl(st, st->registers->status_register);
+	const uint32_t ts_data_irq_mask =
+		AT91_ADC_IER_XRDY |
+		AT91_ADC_IER_YRDY |
+		AT91_ADC_IER_PRDY;
+
+	if (status & st->registers->drdy_mask)
+		handle_adc_eoc_trigger(irq, idev);
+
+	if (status & AT91_ADC_IER_PEN) {
+		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
+		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
+			ts_data_irq_mask);
+		/* Set up period trigger for sampling */
+		at91_adc_writel(st, st->registers->trigger_register,
+			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
+			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
+	} else if (status & AT91_ADC_IER_NOPEN) {
+		at91_adc_writel(st, st->registers->trigger_register, 0);
+		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
+			ts_data_irq_mask);
+		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
+
+		input_report_key(st->ts_input, BTN_TOUCH, 0);
+		input_sync(st->ts_input);
+	} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
+		/* Now all touchscreen data is ready */
+
+		if (status & AT91_ADC_ISR_PENS) {
+			/* validate data by pen contact */
+			at91_ts_sample(st);
+		} else {
+			/* triggered by event that is no pen contact, just read
+			 * them to clean the interrupt and discard all.
+			 */
+			at91_adc_readl(st, AT91_ADC_TSXPOSR);
+			at91_adc_readl(st, AT91_ADC_TSYPOSR);
+			at91_adc_readl(st, AT91_ADC_TSPRESSR);
+		}
+	}
 
 	return IRQ_HANDLED;
 }
@@ -131,6 +279,16 @@ static int at91_adc_channel_init(struct iio_dev *idev)
 	struct at91_adc_state *st = iio_priv(idev);
 	struct iio_chan_spec *chan_array, *timestamp;
 	int bit, idx = 0;
+	unsigned long rsvd_mask = 0;
+
+	/* If touchscreen is enable, then reserve the adc channels */
+	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
+		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
+	else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
+		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
+
+	/* set up the channel mask to reserve touchscreen channels */
+	st->channels_mask &= ~rsvd_mask;
 
 	idev->num_channels = bitmap_weight(&st->channels_mask,
 					   st->num_channels) + 1;
@@ -479,6 +637,39 @@ static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
 
 static const struct of_device_id at91_adc_dt_ids[];
 
+static int at91_adc_probe_dt_ts(struct device_node *node,
+	struct at91_adc_state *st, struct device *dev)
+{
+	int ret;
+	u32 prop;
+
+	ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
+	if (ret) {
+		dev_info(dev, "ADC Touch screen is disabled.\n");
+		return 0;
+	}
+
+	switch (prop) {
+	case 4:
+	case 5:
+		st->touchscreen_type = prop;
+		break;
+	default:
+		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
+		return -EINVAL;
+	}
+
+	prop = 0;
+	of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
+	st->ts_pressure_threshold = prop;
+	if (st->ts_pressure_threshold) {
+		return 0;
+	} else {
+		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
+		return -EINVAL;
+	}
+}
+
 static int at91_adc_probe_dt(struct at91_adc_state *st,
 			     struct platform_device *pdev)
 {
@@ -560,6 +751,12 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
 		i++;
 	}
 
+	/* Check if touchscreen is supported. */
+	if (st->caps->has_ts)
+		return at91_adc_probe_dt_ts(node, st, &idev->dev);
+	else
+		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
+
 	return 0;
 
 error_ret:
@@ -591,6 +788,114 @@ static const struct iio_info at91_adc_info = {
 	.read_raw = &at91_adc_read_raw,
 };
 
+/* Touchscreen related functions */
+static int atmel_ts_open(struct input_dev *dev)
+{
+	struct at91_adc_state *st = input_get_drvdata(dev);
+
+	at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
+	return 0;
+}
+
+static void atmel_ts_close(struct input_dev *dev)
+{
+	struct at91_adc_state *st = input_get_drvdata(dev);
+
+	at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
+}
+
+static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
+{
+	u32 reg = 0, pendbc;
+	int i = 0;
+
+	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
+		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
+	else
+		reg = AT91_ADC_TSMR_TSMODE_5WIRE;
+
+	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
+	 * pen detect noise.
+	 * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
+	 */
+	pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);
+
+	while (pendbc >> ++i)
+		;	/* Empty! Find the shift offset */
+	if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
+		pendbc = i;
+	else
+		pendbc = i - 1;
+
+	if (st->caps->has_tsmr) {
+		reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
+				& AT91_ADC_TSMR_TSAV;
+		reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
+		reg |= AT91_ADC_TSMR_NOTSDMA;
+		reg |= AT91_ADC_TSMR_PENDET_ENA;
+		reg |= 0x03 << 8;	/* TSFREQ, need bigger than TSAV */
+
+		at91_adc_writel(st, AT91_ADC_TSMR, reg);
+	} else {
+		/* TODO: for 9g45 which has no TSMR */
+	}
+
+	/* Change adc internal resistor value for better pen detection,
+	 * default value is 100 kOhm.
+	 * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
+	 * option only available on ES2 and higher
+	 */
+	at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
+			& AT91_ADC_ACR_PENDETSENS);
+
+	/* Sample Peroid Time = (TRGPER + 1) / ADCClock */
+	st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
+			adc_clk_khz / 1000) - 1, 1);
+
+	return 0;
+}
+
+static int at91_ts_register(struct at91_adc_state *st,
+		struct platform_device *pdev)
+{
+	struct input_dev *input;
+	struct iio_dev *idev = iio_priv_to_dev(st);
+	int ret;
+
+	input = input_allocate_device();
+	if (!input) {
+		dev_err(&idev->dev, "Failed to allocate TS device!\n");
+		return -ENOMEM;
+	}
+
+	input->name = DRIVER_NAME;
+	input->id.bustype = BUS_HOST;
+	input->dev.parent = &pdev->dev;
+	input->open = atmel_ts_open;
+	input->close = atmel_ts_close;
+
+	__set_bit(EV_ABS, input->evbit);
+	__set_bit(EV_KEY, input->evbit);
+	__set_bit(BTN_TOUCH, input->keybit);
+	input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
+	input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
+
+	st->ts_input = input;
+	input_set_drvdata(input, st);
+
+	ret = input_register_device(input);
+	if (ret)
+		input_free_device(st->ts_input);
+
+	return ret;
+}
+
+static void at91_ts_unregister(struct at91_adc_state *st)
+{
+	input_unregister_device(st->ts_input);
+}
+
 static int at91_adc_probe(struct platform_device *pdev)
 {
 	unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
@@ -642,7 +947,7 @@ static int at91_adc_probe(struct platform_device *pdev)
 	at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
 	at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
 	ret = request_irq(st->irq,
-			  at91_adc_eoc_trigger,
+			  at91_adc_interrupt,
 			  0,
 			  pdev->dev.driver->name,
 			  idev);
@@ -687,6 +992,10 @@ static int at91_adc_probe(struct platform_device *pdev)
 	mstrclk = clk_get_rate(st->clk);
 	adc_clk = clk_get_rate(st->adc_clk);
 	adc_clk_khz = adc_clk / 1000;
+
+	dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
+		mstrclk, adc_clk);
+
 	prsc = (mstrclk / (2 * adc_clk)) - 1;
 
 	if (!st->startup_time) {
@@ -723,30 +1032,52 @@ static int at91_adc_probe(struct platform_device *pdev)
 	init_waitqueue_head(&st->wq_data_avail);
 	mutex_init(&st->lock);
 
-	ret = at91_adc_buffer_init(idev);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
-		goto error_disable_adc_clk;
-	}
+	/*
+	 * Since touch screen will set trigger register as period trigger. So
+	 * when touch screen is enabled, then we have to disable hardware
+	 * trigger for classic adc.
+	 */
+	if (!st->touchscreen_type) {
+		ret = at91_adc_buffer_init(idev);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
+			goto error_disable_adc_clk;
+		}
 
-	ret = at91_adc_trigger_init(idev);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
-		goto error_unregister_buffer;
+		ret = at91_adc_trigger_init(idev);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
+			at91_adc_buffer_remove(idev);
+			goto error_disable_adc_clk;
+		}
+	} else {
+		if (!st->caps->has_tsmr) {
+			dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
+			goto error_disable_adc_clk;
+		}
+
+		ret = at91_ts_register(st, pdev);
+		if (ret)
+			goto error_disable_adc_clk;
+
+		at91_ts_hw_init(st, adc_clk_khz);
 	}
 
 	ret = iio_device_register(idev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Couldn't register the device.\n");
-		goto error_remove_triggers;
+		goto error_iio_device_register;
 	}
 
 	return 0;
 
-error_remove_triggers:
-	at91_adc_trigger_remove(idev);
-error_unregister_buffer:
-	at91_adc_buffer_remove(idev);
+error_iio_device_register:
+	if (!st->touchscreen_type) {
+		at91_adc_trigger_remove(idev);
+		at91_adc_buffer_remove(idev);
+	} else {
+		at91_ts_unregister(st);
+	}
 error_disable_adc_clk:
 	clk_disable_unprepare(st->adc_clk);
 error_disable_clk:
@@ -762,8 +1093,12 @@ static int at91_adc_remove(struct platform_device *pdev)
 	struct at91_adc_state *st = iio_priv(idev);
 
 	iio_device_unregister(idev);
-	at91_adc_trigger_remove(idev);
-	at91_adc_buffer_remove(idev);
+	if (!st->touchscreen_type) {
+		at91_adc_trigger_remove(idev);
+		at91_adc_buffer_remove(idev);
+	} else {
+		at91_ts_unregister(st);
+	}
 	clk_disable_unprepare(st->adc_clk);
 	clk_disable_unprepare(st->clk);
 	free_irq(st->irq, idev);
@@ -786,6 +1121,7 @@ static struct at91_adc_caps at91sam9260_caps = {
 };
 
 static struct at91_adc_caps at91sam9g45_caps = {
+	.has_ts = true,
 	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
 	.num_channels = 8,
 	.registers = {
@@ -799,6 +1135,10 @@ static struct at91_adc_caps at91sam9g45_caps = {
 };
 
 static struct at91_adc_caps at91sam9x5_caps = {
+	.has_ts = true,
+	.has_tsmr = true,
+	.ts_filter_average = 3,
+	.ts_pen_detect_sensitivity = 2,
 	.calc_startup_ticks = calc_startup_ticks_9x5,
 	.num_channels = 12,
 	.registers = {
@@ -825,7 +1165,7 @@ static struct platform_driver at91_adc_driver = {
 	.probe = at91_adc_probe,
 	.remove = at91_adc_remove,
 	.driver = {
-		   .name = "at91_adc",
+		   .name = DRIVER_NAME,
 		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
 	},
 };
-- 
1.7.9.5

Re: [PATCH 3/3] iio: at91: introduce touch screen support in iio adc driver

[Jonathan Cameron]

On 10/08/13 04:48, Josh Wu wrote:
> AT91 ADC hardware integrate touch screen support. So this patch add touch
> screen support for at91 adc iio driver.
> To enable touch screen support in adc, you need to add the dt parameters:
>   1. which type of touch are used? (4 or 5 wires), sample period time.
>   2. correct pressure detect threshold value.
> 
> In the meantime, since touch screen will use a interal period trigger of adc,
> so it is conflict to other hardware triggers. Driver will disable the hardware
> trigger support if touch screen is enabled.
> 
> This driver has been tested in AT91SAM9X5-EK and SAMA5D3x-EK.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> CC: devicetree@vger.kernel.org
Hi Josh.  I am not going to take this for now both because I want to have
a close read of it when I have more time and because I want input from
Dmitry on this one.

Thanks,

Jonathan
> ---
>  .../devicetree/bindings/arm/atmel-adc.txt          |    7 +
>  arch/arm/mach-at91/include/mach/at91_adc.h         |   34 ++
>  drivers/iio/adc/at91_adc.c                         |  388 ++++++++++++++++++--
>  3 files changed, 405 insertions(+), 24 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/atmel-adc.txt b/Documentation/devicetree/bindings/arm/atmel-adc.txt
> index 0e65e01..d106146 100644
> --- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
> +++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
> @@ -23,6 +23,13 @@ Optional properties:
>  		       resolution will be used.
>    - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
>    - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
> +  - atmel,adc-ts-wires: Number of touch screen wires. Should be 4 or 5. If this
> +                        value is set, then adc driver will enable touch screen
> +                        support.
> +    NOTE: when adc touch screen enabled, the adc hardware trigger will be
> +          disabled. Since touch screen will occupied the trigger register.
> +  - atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
> +                                     make touch detect more precision.
>   
>  Optional trigger Nodes:
>    - Required properties:
> diff --git a/arch/arm/mach-at91/include/mach/at91_adc.h b/arch/arm/mach-at91/include/mach/at91_adc.h
> index 048a57f..c287307 100644
> --- a/arch/arm/mach-at91/include/mach/at91_adc.h
> +++ b/arch/arm/mach-at91/include/mach/at91_adc.h
> @@ -60,14 +60,48 @@
>  #define AT91_ADC_IER		0x24		/* Interrupt Enable Register */
>  #define AT91_ADC_IDR		0x28		/* Interrupt Disable Register */
>  #define AT91_ADC_IMR		0x2C		/* Interrupt Mask Register */
> +#define		AT91_ADC_IER_PEN	(1 << 29)
> +#define		AT91_ADC_IER_NOPEN	(1 << 30)
> +#define		AT91_ADC_IER_XRDY	(1 << 20)
> +#define		AT91_ADC_IER_YRDY	(1 << 21)
> +#define		AT91_ADC_IER_PRDY	(1 << 22)
> +#define		AT91_ADC_ISR_PENS	(1 << 31)
>  
>  #define AT91_ADC_CHR(n)		(0x30 + ((n) * 4))	/* Channel Data Register N */
>  #define		AT91_ADC_DATA		(0x3ff)
>  
>  #define AT91_ADC_CDR0_9X5	(0x50)			/* Channel Data Register 0 for 9X5 */
>  
> +#define AT91_ADC_ACR		0x94	/* Analog Control Register */
> +#define		AT91_ADC_ACR_PENDETSENS	(0x3 << 0)	/* pull-up resistor */
> +
> +#define AT91_ADC_TSMR		0xB0
> +#define		AT91_ADC_TSMR_TSMODE	(3 << 0)	/* Touch Screen Mode */
> +#define			AT91_ADC_TSMR_TSMODE_NONE		(0 << 0)
> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_NO_PRESS	(1 << 0)
> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_PRESS	(2 << 0)
> +#define			AT91_ADC_TSMR_TSMODE_5WIRE		(3 << 0)
> +#define		AT91_ADC_TSMR_TSAV	(3 << 4)	/* Averages samples */
> +#define			AT91_ADC_TSMR_TSAV_(x)		((x) << 4)
> +#define		AT91_ADC_TSMR_SCTIM	(0x0f << 16)	/* Switch closure time */
> +#define		AT91_ADC_TSMR_PENDBC	(0x0f << 28)	/* Pen Debounce time */
> +#define			AT91_ADC_TSMR_PENDBC_(x)	((x) << 28)
> +#define		AT91_ADC_TSMR_NOTSDMA	(1 << 22)	/* No Touchscreen DMA */
> +#define		AT91_ADC_TSMR_PENDET_DIS	(0 << 24)	/* Pen contact detection disable */
> +#define		AT91_ADC_TSMR_PENDET_ENA	(1 << 24)	/* Pen contact detection enable */
> +
> +#define AT91_ADC_TSXPOSR	0xB4
> +#define AT91_ADC_TSYPOSR	0xB8
> +#define AT91_ADC_TSPRESSR	0xBC
> +
>  #define AT91_ADC_TRGR_9260	AT91_ADC_MR
>  #define AT91_ADC_TRGR_9G45	0x08
>  #define AT91_ADC_TRGR_9X5	0xC0
>  
> +/* Trigger Register bit field */
> +#define		AT91_ADC_TRGR_TRGPER	(0xffff << 16)
> +#define			AT91_ADC_TRGR_TRGPER_(x)	((x) << 16)
> +#define		AT91_ADC_TRGR_TRGMOD	(0x7 << 0)
> +#define			AT91_ADC_TRGR_MOD_PERIOD_TRIG	(5 << 0)
> +
>  #endif
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index 22cf61d2..68ddd7f 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -11,6 +11,7 @@
>  #include <linux/clk.h>
>  #include <linux/err.h>
>  #include <linux/io.h>
> +#include <linux/input.h>
>  #include <linux/interrupt.h>
>  #include <linux/jiffies.h>
>  #include <linux/kernel.h>
> @@ -39,7 +40,23 @@
>  #define at91_adc_writel(st, reg, val) \
>  	(writel_relaxed(val, st->reg_base + reg))
>  
> +#define DRIVER_NAME		"at91_adc"
> +#define MAX_POS_BITS		12
> +
> +#define TOUCH_SAMPLE_PERIOD_US		2000	/* 2ms */
> +#define TOUCH_PEN_DETECT_DEBOUNCE_US	200
> +
>  struct at91_adc_caps {
> +	bool	has_ts;		/* Support touch screen */
> +	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
> +	/*
> +	 * Numbers of sampling data will be averaged. Can be 0~3.
> +	 * Hardware can average (2 ^ ts_filter_average) sample data.
> +	 */
> +	u8	ts_filter_average;
> +	/* Pen Detection input pull-up resistor, can be 0~3 */
> +	u8	ts_pen_detect_sensitivity;
> +
>  	/* startup time calculate function */
>  	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
>  
> @@ -47,6 +64,12 @@ struct at91_adc_caps {
>  	struct at91_adc_reg_desc registers;
>  };
>  
> +enum atmel_adc_ts_type {
> +	ATMEL_ADC_TOUCHSCREEN_NONE = 0,
> +	ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
> +	ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
> +};
> +
>  struct at91_adc_state {
>  	struct clk		*adc_clk;
>  	u16			*buffer;
> @@ -71,6 +94,26 @@ struct at91_adc_state {
>  	bool			low_res;	/* the resolution corresponds to the lowest one */
>  	wait_queue_head_t	wq_data_avail;
>  	struct at91_adc_caps	*caps;
> +
> +	/*
> +	 * Following ADC channels are shared by touchscreen:
> +	 *
> +	 * CH0 -- Touch screen XP/UL
> +	 * CH1 -- Touch screen XM/UR
> +	 * CH2 -- Touch screen YP/LL
> +	 * CH3 -- Touch screen YM/Sense
> +	 * CH4 -- Touch screen LR(5-wire only)
> +	 *
> +	 * The bitfields below represents the reserved channel in the
> +	 * touchscreen mode.
> +	 */
> +#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 0)
> +#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 0)
> +	enum atmel_adc_ts_type	touchscreen_type;
> +	struct input_dev	*ts_input;
> +
> +	u16			ts_sample_period_val;
> +	u32			ts_pressure_threshold;
>  };
>  
>  static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
> @@ -105,14 +148,10 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
>  	return IRQ_HANDLED;
>  }
>  
> -static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
> +/* Handler for classic adc channel eoc trigger */
> +void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
>  {
> -	struct iio_dev *idev = private;
>  	struct at91_adc_state *st = iio_priv(idev);
> -	u32 status = at91_adc_readl(st, st->registers->status_register);
> -
> -	if (!(status & st->registers->drdy_mask))
> -		return IRQ_HANDLED;
>  
>  	if (iio_buffer_enabled(idev)) {
>  		disable_irq_nosync(irq);
> @@ -122,6 +161,115 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
>  		st->done = true;
>  		wake_up_interruptible(&st->wq_data_avail);
>  	}
> +}
> +
> +static int at91_ts_sample(struct at91_adc_state *st)
> +{
> +	unsigned int xscale, yscale, reg, z1, z2;
> +	unsigned int x, y, pres, xpos, ypos;
> +	unsigned int rxp = 1;
> +	unsigned int factor = 1000;
> +	struct iio_dev *idev = iio_priv_to_dev(st);
> +
> +	unsigned int xyz_mask_bits = st->res;
> +	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
> +
> +	/* calculate position */
> +	/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
> +	reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
> +	xpos = reg & xyz_mask;
> +	x = (xpos << MAX_POS_BITS) - xpos;
> +	xscale = (reg >> 16) & xyz_mask;
> +	if (xscale == 0) {
> +		dev_err(&idev->dev, "Error: xscale == 0!\n");
> +		return -1;
> +	}
> +	x /= xscale;
> +
> +	/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
> +	reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
> +	ypos = reg & xyz_mask;
> +	y = (ypos << MAX_POS_BITS) - ypos;
> +	yscale = (reg >> 16) & xyz_mask;
> +	if (yscale == 0) {
> +		dev_err(&idev->dev, "Error: yscale == 0!\n");
> +		return -1;
> +	}
> +	y /= yscale;
> +
> +	/* calculate the pressure */
> +	reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
> +	z1 = reg & xyz_mask;
> +	z2 = (reg >> 16) & xyz_mask;
> +
> +	if (z1 != 0)
> +		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
> +			/ factor;
> +	else
> +		pres = st->ts_pressure_threshold;	/* no pen contacted */
> +
> +	dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
> +				xpos, xscale, ypos, yscale, z1, z2, pres);
> +
> +	if (pres < st->ts_pressure_threshold) {
> +		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
> +					x, y, pres / factor);
> +		input_report_abs(st->ts_input, ABS_X, x);
> +		input_report_abs(st->ts_input, ABS_Y, y);
> +		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
> +		input_report_key(st->ts_input, BTN_TOUCH, 1);
> +		input_sync(st->ts_input);
> +	} else {
> +		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
> +	}
> +
> +	return 0;
> +}
> +
> +static irqreturn_t at91_adc_interrupt(int irq, void *private)
> +{
> +	struct iio_dev *idev = private;
> +	struct at91_adc_state *st = iio_priv(idev);
> +	u32 status = at91_adc_readl(st, st->registers->status_register);
> +	const uint32_t ts_data_irq_mask =
> +		AT91_ADC_IER_XRDY |
> +		AT91_ADC_IER_YRDY |
> +		AT91_ADC_IER_PRDY;
> +
> +	if (status & st->registers->drdy_mask)
> +		handle_adc_eoc_trigger(irq, idev);
> +
> +	if (status & AT91_ADC_IER_PEN) {
> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
> +			ts_data_irq_mask);
> +		/* Set up period trigger for sampling */
> +		at91_adc_writel(st, st->registers->trigger_register,
> +			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
> +			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
> +	} else if (status & AT91_ADC_IER_NOPEN) {
> +		at91_adc_writel(st, st->registers->trigger_register, 0);
> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
> +			ts_data_irq_mask);
> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
> +
> +		input_report_key(st->ts_input, BTN_TOUCH, 0);
> +		input_sync(st->ts_input);
> +	} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
> +		/* Now all touchscreen data is ready */
> +
> +		if (status & AT91_ADC_ISR_PENS) {
> +			/* validate data by pen contact */
> +			at91_ts_sample(st);
> +		} else {
> +			/* triggered by event that is no pen contact, just read
> +			 * them to clean the interrupt and discard all.
> +			 */
> +			at91_adc_readl(st, AT91_ADC_TSXPOSR);
> +			at91_adc_readl(st, AT91_ADC_TSYPOSR);
> +			at91_adc_readl(st, AT91_ADC_TSPRESSR);
> +		}
> +	}
>  
>  	return IRQ_HANDLED;
>  }
> @@ -131,6 +279,16 @@ static int at91_adc_channel_init(struct iio_dev *idev)
>  	struct at91_adc_state *st = iio_priv(idev);
>  	struct iio_chan_spec *chan_array, *timestamp;
>  	int bit, idx = 0;
> +	unsigned long rsvd_mask = 0;
> +
> +	/* If touchscreen is enable, then reserve the adc channels */
> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
> +	else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
> +
> +	/* set up the channel mask to reserve touchscreen channels */
> +	st->channels_mask &= ~rsvd_mask;
>  
>  	idev->num_channels = bitmap_weight(&st->channels_mask,
>  					   st->num_channels) + 1;
> @@ -479,6 +637,39 @@ static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
>  
>  static const struct of_device_id at91_adc_dt_ids[];
>  
> +static int at91_adc_probe_dt_ts(struct device_node *node,
> +	struct at91_adc_state *st, struct device *dev)
> +{
> +	int ret;
> +	u32 prop;
> +
> +	ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
> +	if (ret) {
> +		dev_info(dev, "ADC Touch screen is disabled.\n");
> +		return 0;
> +	}
> +
> +	switch (prop) {
> +	case 4:
> +	case 5:
> +		st->touchscreen_type = prop;
> +		break;
> +	default:
> +		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
> +		return -EINVAL;
> +	}
> +
> +	prop = 0;
> +	of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
> +	st->ts_pressure_threshold = prop;
> +	if (st->ts_pressure_threshold) {
> +		return 0;
> +	} else {
> +		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
> +		return -EINVAL;
> +	}
> +}
> +
>  static int at91_adc_probe_dt(struct at91_adc_state *st,
>  			     struct platform_device *pdev)
>  {
> @@ -560,6 +751,12 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
>  		i++;
>  	}
>  
> +	/* Check if touchscreen is supported. */
> +	if (st->caps->has_ts)
> +		return at91_adc_probe_dt_ts(node, st, &idev->dev);
> +	else
> +		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
> +
>  	return 0;
>  
>  error_ret:
> @@ -591,6 +788,114 @@ static const struct iio_info at91_adc_info = {
>  	.read_raw = &at91_adc_read_raw,
>  };
>  
> +/* Touchscreen related functions */
> +static int atmel_ts_open(struct input_dev *dev)
> +{
> +	struct at91_adc_state *st = input_get_drvdata(dev);
> +
> +	at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
> +	return 0;
> +}
> +
> +static void atmel_ts_close(struct input_dev *dev)
> +{
> +	struct at91_adc_state *st = input_get_drvdata(dev);
> +
> +	at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
> +}
> +
> +static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
> +{
> +	u32 reg = 0, pendbc;
> +	int i = 0;
> +
> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
> +		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
> +	else
> +		reg = AT91_ADC_TSMR_TSMODE_5WIRE;
> +
> +	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
> +	 * pen detect noise.
> +	 * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
> +	 */
> +	pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);
> +
> +	while (pendbc >> ++i)
> +		;	/* Empty! Find the shift offset */
> +	if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
> +		pendbc = i;
> +	else
> +		pendbc = i - 1;
> +
> +	if (st->caps->has_tsmr) {
> +		reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
> +				& AT91_ADC_TSMR_TSAV;
> +		reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
> +		reg |= AT91_ADC_TSMR_NOTSDMA;
> +		reg |= AT91_ADC_TSMR_PENDET_ENA;
> +		reg |= 0x03 << 8;	/* TSFREQ, need bigger than TSAV */
> +
> +		at91_adc_writel(st, AT91_ADC_TSMR, reg);
> +	} else {
> +		/* TODO: for 9g45 which has no TSMR */
> +	}
> +
> +	/* Change adc internal resistor value for better pen detection,
> +	 * default value is 100 kOhm.
> +	 * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
> +	 * option only available on ES2 and higher
> +	 */
> +	at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
> +			& AT91_ADC_ACR_PENDETSENS);
> +
> +	/* Sample Peroid Time = (TRGPER + 1) / ADCClock */
> +	st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
> +			adc_clk_khz / 1000) - 1, 1);
> +
> +	return 0;
> +}
> +
> +static int at91_ts_register(struct at91_adc_state *st,
> +		struct platform_device *pdev)
> +{
> +	struct input_dev *input;
> +	struct iio_dev *idev = iio_priv_to_dev(st);
> +	int ret;
> +
> +	input = input_allocate_device();
> +	if (!input) {
> +		dev_err(&idev->dev, "Failed to allocate TS device!\n");
> +		return -ENOMEM;
> +	}
> +
> +	input->name = DRIVER_NAME;
> +	input->id.bustype = BUS_HOST;
> +	input->dev.parent = &pdev->dev;
> +	input->open = atmel_ts_open;
> +	input->close = atmel_ts_close;
> +
> +	__set_bit(EV_ABS, input->evbit);
> +	__set_bit(EV_KEY, input->evbit);
> +	__set_bit(BTN_TOUCH, input->keybit);
> +	input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
> +	input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
> +	input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
> +
> +	st->ts_input = input;
> +	input_set_drvdata(input, st);
> +
> +	ret = input_register_device(input);
> +	if (ret)
> +		input_free_device(st->ts_input);
> +
> +	return ret;
> +}
> +
> +static void at91_ts_unregister(struct at91_adc_state *st)
> +{
> +	input_unregister_device(st->ts_input);
> +}
> +
>  static int at91_adc_probe(struct platform_device *pdev)
>  {
>  	unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
> @@ -642,7 +947,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
>  	at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
>  	ret = request_irq(st->irq,
> -			  at91_adc_eoc_trigger,
> +			  at91_adc_interrupt,
>  			  0,
>  			  pdev->dev.driver->name,
>  			  idev);
> @@ -687,6 +992,10 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	mstrclk = clk_get_rate(st->clk);
>  	adc_clk = clk_get_rate(st->adc_clk);
>  	adc_clk_khz = adc_clk / 1000;
> +
> +	dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
> +		mstrclk, adc_clk);
> +
>  	prsc = (mstrclk / (2 * adc_clk)) - 1;
>  
>  	if (!st->startup_time) {
> @@ -723,30 +1032,52 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	init_waitqueue_head(&st->wq_data_avail);
>  	mutex_init(&st->lock);
>  
> -	ret = at91_adc_buffer_init(idev);
> -	if (ret < 0) {
> -		dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
> -		goto error_disable_adc_clk;
> -	}
> +	/*
> +	 * Since touch screen will set trigger register as period trigger. So
> +	 * when touch screen is enabled, then we have to disable hardware
> +	 * trigger for classic adc.
> +	 */
> +	if (!st->touchscreen_type) {
> +		ret = at91_adc_buffer_init(idev);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
> +			goto error_disable_adc_clk;
> +		}
>  
> -	ret = at91_adc_trigger_init(idev);
> -	if (ret < 0) {
> -		dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
> -		goto error_unregister_buffer;
> +		ret = at91_adc_trigger_init(idev);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
> +			at91_adc_buffer_remove(idev);
> +			goto error_disable_adc_clk;
> +		}
> +	} else {
> +		if (!st->caps->has_tsmr) {
> +			dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
> +			goto error_disable_adc_clk;
> +		}
> +
> +		ret = at91_ts_register(st, pdev);
> +		if (ret)
> +			goto error_disable_adc_clk;
> +
> +		at91_ts_hw_init(st, adc_clk_khz);
>  	}
>  
>  	ret = iio_device_register(idev);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "Couldn't register the device.\n");
> -		goto error_remove_triggers;
> +		goto error_iio_device_register;
>  	}
>  
>  	return 0;
>  
> -error_remove_triggers:
> -	at91_adc_trigger_remove(idev);
> -error_unregister_buffer:
> -	at91_adc_buffer_remove(idev);
> +error_iio_device_register:
> +	if (!st->touchscreen_type) {
> +		at91_adc_trigger_remove(idev);
> +		at91_adc_buffer_remove(idev);
> +	} else {
> +		at91_ts_unregister(st);
> +	}
>  error_disable_adc_clk:
>  	clk_disable_unprepare(st->adc_clk);
>  error_disable_clk:
> @@ -762,8 +1093,12 @@ static int at91_adc_remove(struct platform_device *pdev)
>  	struct at91_adc_state *st = iio_priv(idev);
>  
>  	iio_device_unregister(idev);
> -	at91_adc_trigger_remove(idev);
> -	at91_adc_buffer_remove(idev);
> +	if (!st->touchscreen_type) {
> +		at91_adc_trigger_remove(idev);
> +		at91_adc_buffer_remove(idev);
> +	} else {
> +		at91_ts_unregister(st);
> +	}
>  	clk_disable_unprepare(st->adc_clk);
>  	clk_disable_unprepare(st->clk);
>  	free_irq(st->irq, idev);
> @@ -786,6 +1121,7 @@ static struct at91_adc_caps at91sam9260_caps = {
>  };
>  
>  static struct at91_adc_caps at91sam9g45_caps = {
> +	.has_ts = true,
>  	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
>  	.num_channels = 8,
>  	.registers = {
> @@ -799,6 +1135,10 @@ static struct at91_adc_caps at91sam9g45_caps = {
>  };
>  
>  static struct at91_adc_caps at91sam9x5_caps = {
> +	.has_ts = true,
> +	.has_tsmr = true,
> +	.ts_filter_average = 3,
> +	.ts_pen_detect_sensitivity = 2,
>  	.calc_startup_ticks = calc_startup_ticks_9x5,
>  	.num_channels = 12,
>  	.registers = {
> @@ -825,7 +1165,7 @@ static struct platform_driver at91_adc_driver = {
>  	.probe = at91_adc_probe,
>  	.remove = at91_adc_remove,
>  	.driver = {
> -		   .name = "at91_adc",
> +		   .name = DRIVER_NAME,
>  		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
>  	},
>  };
> 

Re: [PATCH 3/3] iio: at91: introduce touch screen support in iio adc driver

[Josh Wu]

Hi, Dimitry

Could give some feedback for this v4  patch if you have time? Since It 
has been stuck for a while.
Thanks.

Best Regards,
Josh Wu

On 10/10/2013 4:14 AM, Jonathan Cameron wrote:
> On 10/08/13 04:48, Josh Wu wrote:
>> AT91 ADC hardware integrate touch screen support. So this patch add touch
>> screen support for at91 adc iio driver.
>> To enable touch screen support in adc, you need to add the dt parameters:
>>    1. which type of touch are used? (4 or 5 wires), sample period time.
>>    2. correct pressure detect threshold value.
>>
>> In the meantime, since touch screen will use a interal period trigger of adc,
>> so it is conflict to other hardware triggers. Driver will disable the hardware
>> trigger support if touch screen is enabled.
>>
>> This driver has been tested in AT91SAM9X5-EK and SAMA5D3x-EK.
>>
>> Signed-off-by: Josh Wu <josh.wu@atmel.com>
>> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>> CC: devicetree@vger.kernel.org
> Hi Josh.  I am not going to take this for now both because I want to have
> a close read of it when I have more time and because I want input from
> Dmitry on this one.
>
> Thanks,
>
> Jonathan
>> ---
>>   .../devicetree/bindings/arm/atmel-adc.txt          |    7 +
>>   arch/arm/mach-at91/include/mach/at91_adc.h         |   34 ++
>>   drivers/iio/adc/at91_adc.c                         |  388 ++++++++++++++++++--
>>   3 files changed, 405 insertions(+), 24 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/arm/atmel-adc.txt b/Documentation/devicetree/bindings/arm/atmel-adc.txt
>> index 0e65e01..d106146 100644
>> --- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
>> +++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
>> @@ -23,6 +23,13 @@ Optional properties:
>>   		       resolution will be used.
>>     - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
>>     - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
>> +  - atmel,adc-ts-wires: Number of touch screen wires. Should be 4 or 5. If this
>> +                        value is set, then adc driver will enable touch screen
>> +                        support.
>> +    NOTE: when adc touch screen enabled, the adc hardware trigger will be
>> +          disabled. Since touch screen will occupied the trigger register.
>> +  - atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
>> +                                     make touch detect more precision.
>>    
>>   Optional trigger Nodes:
>>     - Required properties:
>> diff --git a/arch/arm/mach-at91/include/mach/at91_adc.h b/arch/arm/mach-at91/include/mach/at91_adc.h
>> index 048a57f..c287307 100644
>> --- a/arch/arm/mach-at91/include/mach/at91_adc.h
>> +++ b/arch/arm/mach-at91/include/mach/at91_adc.h
>> @@ -60,14 +60,48 @@
>>   #define AT91_ADC_IER		0x24		/* Interrupt Enable Register */
>>   #define AT91_ADC_IDR		0x28		/* Interrupt Disable Register */
>>   #define AT91_ADC_IMR		0x2C		/* Interrupt Mask Register */
>> +#define		AT91_ADC_IER_PEN	(1 << 29)
>> +#define		AT91_ADC_IER_NOPEN	(1 << 30)
>> +#define		AT91_ADC_IER_XRDY	(1 << 20)
>> +#define		AT91_ADC_IER_YRDY	(1 << 21)
>> +#define		AT91_ADC_IER_PRDY	(1 << 22)
>> +#define		AT91_ADC_ISR_PENS	(1 << 31)
>>   
>>   #define AT91_ADC_CHR(n)		(0x30 + ((n) * 4))	/* Channel Data Register N */
>>   #define		AT91_ADC_DATA		(0x3ff)
>>   
>>   #define AT91_ADC_CDR0_9X5	(0x50)			/* Channel Data Register 0 for 9X5 */
>>   
>> +#define AT91_ADC_ACR		0x94	/* Analog Control Register */
>> +#define		AT91_ADC_ACR_PENDETSENS	(0x3 << 0)	/* pull-up resistor */
>> +
>> +#define AT91_ADC_TSMR		0xB0
>> +#define		AT91_ADC_TSMR_TSMODE	(3 << 0)	/* Touch Screen Mode */
>> +#define			AT91_ADC_TSMR_TSMODE_NONE		(0 << 0)
>> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_NO_PRESS	(1 << 0)
>> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_PRESS	(2 << 0)
>> +#define			AT91_ADC_TSMR_TSMODE_5WIRE		(3 << 0)
>> +#define		AT91_ADC_TSMR_TSAV	(3 << 4)	/* Averages samples */
>> +#define			AT91_ADC_TSMR_TSAV_(x)		((x) << 4)
>> +#define		AT91_ADC_TSMR_SCTIM	(0x0f << 16)	/* Switch closure time */
>> +#define		AT91_ADC_TSMR_PENDBC	(0x0f << 28)	/* Pen Debounce time */
>> +#define			AT91_ADC_TSMR_PENDBC_(x)	((x) << 28)
>> +#define		AT91_ADC_TSMR_NOTSDMA	(1 << 22)	/* No Touchscreen DMA */
>> +#define		AT91_ADC_TSMR_PENDET_DIS	(0 << 24)	/* Pen contact detection disable */
>> +#define		AT91_ADC_TSMR_PENDET_ENA	(1 << 24)	/* Pen contact detection enable */
>> +
>> +#define AT91_ADC_TSXPOSR	0xB4
>> +#define AT91_ADC_TSYPOSR	0xB8
>> +#define AT91_ADC_TSPRESSR	0xBC
>> +
>>   #define AT91_ADC_TRGR_9260	AT91_ADC_MR
>>   #define AT91_ADC_TRGR_9G45	0x08
>>   #define AT91_ADC_TRGR_9X5	0xC0
>>   
>> +/* Trigger Register bit field */
>> +#define		AT91_ADC_TRGR_TRGPER	(0xffff << 16)
>> +#define			AT91_ADC_TRGR_TRGPER_(x)	((x) << 16)
>> +#define		AT91_ADC_TRGR_TRGMOD	(0x7 << 0)
>> +#define			AT91_ADC_TRGR_MOD_PERIOD_TRIG	(5 << 0)
>> +
>>   #endif
>> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
>> index 22cf61d2..68ddd7f 100644
>> --- a/drivers/iio/adc/at91_adc.c
>> +++ b/drivers/iio/adc/at91_adc.c
>> @@ -11,6 +11,7 @@
>>   #include <linux/clk.h>
>>   #include <linux/err.h>
>>   #include <linux/io.h>
>> +#include <linux/input.h>
>>   #include <linux/interrupt.h>
>>   #include <linux/jiffies.h>
>>   #include <linux/kernel.h>
>> @@ -39,7 +40,23 @@
>>   #define at91_adc_writel(st, reg, val) \
>>   	(writel_relaxed(val, st->reg_base + reg))
>>   
>> +#define DRIVER_NAME		"at91_adc"
>> +#define MAX_POS_BITS		12
>> +
>> +#define TOUCH_SAMPLE_PERIOD_US		2000	/* 2ms */
>> +#define TOUCH_PEN_DETECT_DEBOUNCE_US	200
>> +
>>   struct at91_adc_caps {
>> +	bool	has_ts;		/* Support touch screen */
>> +	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
>> +	/*
>> +	 * Numbers of sampling data will be averaged. Can be 0~3.
>> +	 * Hardware can average (2 ^ ts_filter_average) sample data.
>> +	 */
>> +	u8	ts_filter_average;
>> +	/* Pen Detection input pull-up resistor, can be 0~3 */
>> +	u8	ts_pen_detect_sensitivity;
>> +
>>   	/* startup time calculate function */
>>   	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
>>   
>> @@ -47,6 +64,12 @@ struct at91_adc_caps {
>>   	struct at91_adc_reg_desc registers;
>>   };
>>   
>> +enum atmel_adc_ts_type {
>> +	ATMEL_ADC_TOUCHSCREEN_NONE = 0,
>> +	ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
>> +	ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
>> +};
>> +
>>   struct at91_adc_state {
>>   	struct clk		*adc_clk;
>>   	u16			*buffer;
>> @@ -71,6 +94,26 @@ struct at91_adc_state {
>>   	bool			low_res;	/* the resolution corresponds to the lowest one */
>>   	wait_queue_head_t	wq_data_avail;
>>   	struct at91_adc_caps	*caps;
>> +
>> +	/*
>> +	 * Following ADC channels are shared by touchscreen:
>> +	 *
>> +	 * CH0 -- Touch screen XP/UL
>> +	 * CH1 -- Touch screen XM/UR
>> +	 * CH2 -- Touch screen YP/LL
>> +	 * CH3 -- Touch screen YM/Sense
>> +	 * CH4 -- Touch screen LR(5-wire only)
>> +	 *
>> +	 * The bitfields below represents the reserved channel in the
>> +	 * touchscreen mode.
>> +	 */
>> +#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 0)
>> +#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 0)
>> +	enum atmel_adc_ts_type	touchscreen_type;
>> +	struct input_dev	*ts_input;
>> +
>> +	u16			ts_sample_period_val;
>> +	u32			ts_pressure_threshold;
>>   };
>>   
>>   static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
>> @@ -105,14 +148,10 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
>>   	return IRQ_HANDLED;
>>   }
>>   
>> -static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
>> +/* Handler for classic adc channel eoc trigger */
>> +void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
>>   {
>> -	struct iio_dev *idev = private;
>>   	struct at91_adc_state *st = iio_priv(idev);
>> -	u32 status = at91_adc_readl(st, st->registers->status_register);
>> -
>> -	if (!(status & st->registers->drdy_mask))
>> -		return IRQ_HANDLED;
>>   
>>   	if (iio_buffer_enabled(idev)) {
>>   		disable_irq_nosync(irq);
>> @@ -122,6 +161,115 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
>>   		st->done = true;
>>   		wake_up_interruptible(&st->wq_data_avail);
>>   	}
>> +}
>> +
>> +static int at91_ts_sample(struct at91_adc_state *st)
>> +{
>> +	unsigned int xscale, yscale, reg, z1, z2;
>> +	unsigned int x, y, pres, xpos, ypos;
>> +	unsigned int rxp = 1;
>> +	unsigned int factor = 1000;
>> +	struct iio_dev *idev = iio_priv_to_dev(st);
>> +
>> +	unsigned int xyz_mask_bits = st->res;
>> +	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
>> +
>> +	/* calculate position */
>> +	/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
>> +	reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
>> +	xpos = reg & xyz_mask;
>> +	x = (xpos << MAX_POS_BITS) - xpos;
>> +	xscale = (reg >> 16) & xyz_mask;
>> +	if (xscale == 0) {
>> +		dev_err(&idev->dev, "Error: xscale == 0!\n");
>> +		return -1;
>> +	}
>> +	x /= xscale;
>> +
>> +	/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
>> +	reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
>> +	ypos = reg & xyz_mask;
>> +	y = (ypos << MAX_POS_BITS) - ypos;
>> +	yscale = (reg >> 16) & xyz_mask;
>> +	if (yscale == 0) {
>> +		dev_err(&idev->dev, "Error: yscale == 0!\n");
>> +		return -1;
>> +	}
>> +	y /= yscale;
>> +
>> +	/* calculate the pressure */
>> +	reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
>> +	z1 = reg & xyz_mask;
>> +	z2 = (reg >> 16) & xyz_mask;
>> +
>> +	if (z1 != 0)
>> +		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
>> +			/ factor;
>> +	else
>> +		pres = st->ts_pressure_threshold;	/* no pen contacted */
>> +
>> +	dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
>> +				xpos, xscale, ypos, yscale, z1, z2, pres);
>> +
>> +	if (pres < st->ts_pressure_threshold) {
>> +		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
>> +					x, y, pres / factor);
>> +		input_report_abs(st->ts_input, ABS_X, x);
>> +		input_report_abs(st->ts_input, ABS_Y, y);
>> +		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
>> +		input_report_key(st->ts_input, BTN_TOUCH, 1);
>> +		input_sync(st->ts_input);
>> +	} else {
>> +		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static irqreturn_t at91_adc_interrupt(int irq, void *private)
>> +{
>> +	struct iio_dev *idev = private;
>> +	struct at91_adc_state *st = iio_priv(idev);
>> +	u32 status = at91_adc_readl(st, st->registers->status_register);
>> +	const uint32_t ts_data_irq_mask =
>> +		AT91_ADC_IER_XRDY |
>> +		AT91_ADC_IER_YRDY |
>> +		AT91_ADC_IER_PRDY;
>> +
>> +	if (status & st->registers->drdy_mask)
>> +		handle_adc_eoc_trigger(irq, idev);
>> +
>> +	if (status & AT91_ADC_IER_PEN) {
>> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
>> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
>> +			ts_data_irq_mask);
>> +		/* Set up period trigger for sampling */
>> +		at91_adc_writel(st, st->registers->trigger_register,
>> +			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
>> +			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
>> +	} else if (status & AT91_ADC_IER_NOPEN) {
>> +		at91_adc_writel(st, st->registers->trigger_register, 0);
>> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
>> +			ts_data_irq_mask);
>> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
>> +
>> +		input_report_key(st->ts_input, BTN_TOUCH, 0);
>> +		input_sync(st->ts_input);
>> +	} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
>> +		/* Now all touchscreen data is ready */
>> +
>> +		if (status & AT91_ADC_ISR_PENS) {
>> +			/* validate data by pen contact */
>> +			at91_ts_sample(st);
>> +		} else {
>> +			/* triggered by event that is no pen contact, just read
>> +			 * them to clean the interrupt and discard all.
>> +			 */
>> +			at91_adc_readl(st, AT91_ADC_TSXPOSR);
>> +			at91_adc_readl(st, AT91_ADC_TSYPOSR);
>> +			at91_adc_readl(st, AT91_ADC_TSPRESSR);
>> +		}
>> +	}
>>   
>>   	return IRQ_HANDLED;
>>   }
>> @@ -131,6 +279,16 @@ static int at91_adc_channel_init(struct iio_dev *idev)
>>   	struct at91_adc_state *st = iio_priv(idev);
>>   	struct iio_chan_spec *chan_array, *timestamp;
>>   	int bit, idx = 0;
>> +	unsigned long rsvd_mask = 0;
>> +
>> +	/* If touchscreen is enable, then reserve the adc channels */
>> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
>> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
>> +	else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
>> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
>> +
>> +	/* set up the channel mask to reserve touchscreen channels */
>> +	st->channels_mask &= ~rsvd_mask;
>>   
>>   	idev->num_channels = bitmap_weight(&st->channels_mask,
>>   					   st->num_channels) + 1;
>> @@ -479,6 +637,39 @@ static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
>>   
>>   static const struct of_device_id at91_adc_dt_ids[];
>>   
>> +static int at91_adc_probe_dt_ts(struct device_node *node,
>> +	struct at91_adc_state *st, struct device *dev)
>> +{
>> +	int ret;
>> +	u32 prop;
>> +
>> +	ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
>> +	if (ret) {
>> +		dev_info(dev, "ADC Touch screen is disabled.\n");
>> +		return 0;
>> +	}
>> +
>> +	switch (prop) {
>> +	case 4:
>> +	case 5:
>> +		st->touchscreen_type = prop;
>> +		break;
>> +	default:
>> +		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
>> +		return -EINVAL;
>> +	}
>> +
>> +	prop = 0;
>> +	of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
>> +	st->ts_pressure_threshold = prop;
>> +	if (st->ts_pressure_threshold) {
>> +		return 0;
>> +	} else {
>> +		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>>   static int at91_adc_probe_dt(struct at91_adc_state *st,
>>   			     struct platform_device *pdev)
>>   {
>> @@ -560,6 +751,12 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
>>   		i++;
>>   	}
>>   
>> +	/* Check if touchscreen is supported. */
>> +	if (st->caps->has_ts)
>> +		return at91_adc_probe_dt_ts(node, st, &idev->dev);
>> +	else
>> +		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
>> +
>>   	return 0;
>>   
>>   error_ret:
>> @@ -591,6 +788,114 @@ static const struct iio_info at91_adc_info = {
>>   	.read_raw = &at91_adc_read_raw,
>>   };
>>   
>> +/* Touchscreen related functions */
>> +static int atmel_ts_open(struct input_dev *dev)
>> +{
>> +	struct at91_adc_state *st = input_get_drvdata(dev);
>> +
>> +	at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
>> +	return 0;
>> +}
>> +
>> +static void atmel_ts_close(struct input_dev *dev)
>> +{
>> +	struct at91_adc_state *st = input_get_drvdata(dev);
>> +
>> +	at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
>> +}
>> +
>> +static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
>> +{
>> +	u32 reg = 0, pendbc;
>> +	int i = 0;
>> +
>> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
>> +		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
>> +	else
>> +		reg = AT91_ADC_TSMR_TSMODE_5WIRE;
>> +
>> +	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
>> +	 * pen detect noise.
>> +	 * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
>> +	 */
>> +	pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);
>> +
>> +	while (pendbc >> ++i)
>> +		;	/* Empty! Find the shift offset */
>> +	if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
>> +		pendbc = i;
>> +	else
>> +		pendbc = i - 1;
>> +
>> +	if (st->caps->has_tsmr) {
>> +		reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
>> +				& AT91_ADC_TSMR_TSAV;
>> +		reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
>> +		reg |= AT91_ADC_TSMR_NOTSDMA;
>> +		reg |= AT91_ADC_TSMR_PENDET_ENA;
>> +		reg |= 0x03 << 8;	/* TSFREQ, need bigger than TSAV */
>> +
>> +		at91_adc_writel(st, AT91_ADC_TSMR, reg);
>> +	} else {
>> +		/* TODO: for 9g45 which has no TSMR */
>> +	}
>> +
>> +	/* Change adc internal resistor value for better pen detection,
>> +	 * default value is 100 kOhm.
>> +	 * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
>> +	 * option only available on ES2 and higher
>> +	 */
>> +	at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
>> +			& AT91_ADC_ACR_PENDETSENS);
>> +
>> +	/* Sample Peroid Time = (TRGPER + 1) / ADCClock */
>> +	st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
>> +			adc_clk_khz / 1000) - 1, 1);
>> +
>> +	return 0;
>> +}
>> +
>> +static int at91_ts_register(struct at91_adc_state *st,
>> +		struct platform_device *pdev)
>> +{
>> +	struct input_dev *input;
>> +	struct iio_dev *idev = iio_priv_to_dev(st);
>> +	int ret;
>> +
>> +	input = input_allocate_device();
>> +	if (!input) {
>> +		dev_err(&idev->dev, "Failed to allocate TS device!\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	input->name = DRIVER_NAME;
>> +	input->id.bustype = BUS_HOST;
>> +	input->dev.parent = &pdev->dev;
>> +	input->open = atmel_ts_open;
>> +	input->close = atmel_ts_close;
>> +
>> +	__set_bit(EV_ABS, input->evbit);
>> +	__set_bit(EV_KEY, input->evbit);
>> +	__set_bit(BTN_TOUCH, input->keybit);
>> +	input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
>> +	input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
>> +	input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
>> +
>> +	st->ts_input = input;
>> +	input_set_drvdata(input, st);
>> +
>> +	ret = input_register_device(input);
>> +	if (ret)
>> +		input_free_device(st->ts_input);
>> +
>> +	return ret;
>> +}
>> +
>> +static void at91_ts_unregister(struct at91_adc_state *st)
>> +{
>> +	input_unregister_device(st->ts_input);
>> +}
>> +
>>   static int at91_adc_probe(struct platform_device *pdev)
>>   {
>>   	unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
>> @@ -642,7 +947,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>>   	at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
>>   	at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
>>   	ret = request_irq(st->irq,
>> -			  at91_adc_eoc_trigger,
>> +			  at91_adc_interrupt,
>>   			  0,
>>   			  pdev->dev.driver->name,
>>   			  idev);
>> @@ -687,6 +992,10 @@ static int at91_adc_probe(struct platform_device *pdev)
>>   	mstrclk = clk_get_rate(st->clk);
>>   	adc_clk = clk_get_rate(st->adc_clk);
>>   	adc_clk_khz = adc_clk / 1000;
>> +
>> +	dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
>> +		mstrclk, adc_clk);
>> +
>>   	prsc = (mstrclk / (2 * adc_clk)) - 1;
>>   
>>   	if (!st->startup_time) {
>> @@ -723,30 +1032,52 @@ static int at91_adc_probe(struct platform_device *pdev)
>>   	init_waitqueue_head(&st->wq_data_avail);
>>   	mutex_init(&st->lock);
>>   
>> -	ret = at91_adc_buffer_init(idev);
>> -	if (ret < 0) {
>> -		dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
>> -		goto error_disable_adc_clk;
>> -	}
>> +	/*
>> +	 * Since touch screen will set trigger register as period trigger. So
>> +	 * when touch screen is enabled, then we have to disable hardware
>> +	 * trigger for classic adc.
>> +	 */
>> +	if (!st->touchscreen_type) {
>> +		ret = at91_adc_buffer_init(idev);
>> +		if (ret < 0) {
>> +			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
>> +			goto error_disable_adc_clk;
>> +		}
>>   
>> -	ret = at91_adc_trigger_init(idev);
>> -	if (ret < 0) {
>> -		dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
>> -		goto error_unregister_buffer;
>> +		ret = at91_adc_trigger_init(idev);
>> +		if (ret < 0) {
>> +			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
>> +			at91_adc_buffer_remove(idev);
>> +			goto error_disable_adc_clk;
>> +		}
>> +	} else {
>> +		if (!st->caps->has_tsmr) {
>> +			dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
>> +			goto error_disable_adc_clk;
>> +		}
>> +
>> +		ret = at91_ts_register(st, pdev);
>> +		if (ret)
>> +			goto error_disable_adc_clk;
>> +
>> +		at91_ts_hw_init(st, adc_clk_khz);
>>   	}
>>   
>>   	ret = iio_device_register(idev);
>>   	if (ret < 0) {
>>   		dev_err(&pdev->dev, "Couldn't register the device.\n");
>> -		goto error_remove_triggers;
>> +		goto error_iio_device_register;
>>   	}
>>   
>>   	return 0;
>>   
>> -error_remove_triggers:
>> -	at91_adc_trigger_remove(idev);
>> -error_unregister_buffer:
>> -	at91_adc_buffer_remove(idev);
>> +error_iio_device_register:
>> +	if (!st->touchscreen_type) {
>> +		at91_adc_trigger_remove(idev);
>> +		at91_adc_buffer_remove(idev);
>> +	} else {
>> +		at91_ts_unregister(st);
>> +	}
>>   error_disable_adc_clk:
>>   	clk_disable_unprepare(st->adc_clk);
>>   error_disable_clk:
>> @@ -762,8 +1093,12 @@ static int at91_adc_remove(struct platform_device *pdev)
>>   	struct at91_adc_state *st = iio_priv(idev);
>>   
>>   	iio_device_unregister(idev);
>> -	at91_adc_trigger_remove(idev);
>> -	at91_adc_buffer_remove(idev);
>> +	if (!st->touchscreen_type) {
>> +		at91_adc_trigger_remove(idev);
>> +		at91_adc_buffer_remove(idev);
>> +	} else {
>> +		at91_ts_unregister(st);
>> +	}
>>   	clk_disable_unprepare(st->adc_clk);
>>   	clk_disable_unprepare(st->clk);
>>   	free_irq(st->irq, idev);
>> @@ -786,6 +1121,7 @@ static struct at91_adc_caps at91sam9260_caps = {
>>   };
>>   
>>   static struct at91_adc_caps at91sam9g45_caps = {
>> +	.has_ts = true,
>>   	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
>>   	.num_channels = 8,
>>   	.registers = {
>> @@ -799,6 +1135,10 @@ static struct at91_adc_caps at91sam9g45_caps = {
>>   };
>>   
>>   static struct at91_adc_caps at91sam9x5_caps = {
>> +	.has_ts = true,
>> +	.has_tsmr = true,
>> +	.ts_filter_average = 3,
>> +	.ts_pen_detect_sensitivity = 2,
>>   	.calc_startup_ticks = calc_startup_ticks_9x5,
>>   	.num_channels = 12,
>>   	.registers = {
>> @@ -825,7 +1165,7 @@ static struct platform_driver at91_adc_driver = {
>>   	.probe = at91_adc_probe,
>>   	.remove = at91_adc_remove,
>>   	.driver = {
>> -		   .name = "at91_adc",
>> +		   .name = DRIVER_NAME,
>>   		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
>>   	},
>>   };
>>

Re: [PATCH 3/3] iio: at91: introduce touch screen support in iio adc driver

[Dmitry Torokhov]

Hi Josh,

On Tue, Oct 08, 2013 at 11:48:56AM +0800, Josh Wu wrote:
> AT91 ADC hardware integrate touch screen support. So this patch add touch
> screen support for at91 adc iio driver.
> To enable touch screen support in adc, you need to add the dt parameters:
>   1. which type of touch are used? (4 or 5 wires), sample period time.
>   2. correct pressure detect threshold value.
> 
> In the meantime, since touch screen will use a interal period trigger of adc,
> so it is conflict to other hardware triggers. Driver will disable the hardware
> trigger support if touch screen is enabled.
> 
> This driver has been tested in AT91SAM9X5-EK and SAMA5D3x-EK.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> CC: devicetree@vger.kernel.org

Input stuff looks reasonable to me.

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

> ---
>  .../devicetree/bindings/arm/atmel-adc.txt          |    7 +
>  arch/arm/mach-at91/include/mach/at91_adc.h         |   34 ++
>  drivers/iio/adc/at91_adc.c                         |  388 ++++++++++++++++++--
>  3 files changed, 405 insertions(+), 24 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/atmel-adc.txt b/Documentation/devicetree/bindings/arm/atmel-adc.txt
> index 0e65e01..d106146 100644
> --- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
> +++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
> @@ -23,6 +23,13 @@ Optional properties:
>  		       resolution will be used.
>    - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
>    - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
> +  - atmel,adc-ts-wires: Number of touch screen wires. Should be 4 or 5. If this
> +                        value is set, then adc driver will enable touch screen
> +                        support.
> +    NOTE: when adc touch screen enabled, the adc hardware trigger will be
> +          disabled. Since touch screen will occupied the trigger register.
> +  - atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
> +                                     make touch detect more precision.
>   
>  Optional trigger Nodes:
>    - Required properties:
> diff --git a/arch/arm/mach-at91/include/mach/at91_adc.h b/arch/arm/mach-at91/include/mach/at91_adc.h
> index 048a57f..c287307 100644
> --- a/arch/arm/mach-at91/include/mach/at91_adc.h
> +++ b/arch/arm/mach-at91/include/mach/at91_adc.h
> @@ -60,14 +60,48 @@
>  #define AT91_ADC_IER		0x24		/* Interrupt Enable Register */
>  #define AT91_ADC_IDR		0x28		/* Interrupt Disable Register */
>  #define AT91_ADC_IMR		0x2C		/* Interrupt Mask Register */
> +#define		AT91_ADC_IER_PEN	(1 << 29)
> +#define		AT91_ADC_IER_NOPEN	(1 << 30)
> +#define		AT91_ADC_IER_XRDY	(1 << 20)
> +#define		AT91_ADC_IER_YRDY	(1 << 21)
> +#define		AT91_ADC_IER_PRDY	(1 << 22)
> +#define		AT91_ADC_ISR_PENS	(1 << 31)
>  
>  #define AT91_ADC_CHR(n)		(0x30 + ((n) * 4))	/* Channel Data Register N */
>  #define		AT91_ADC_DATA		(0x3ff)
>  
>  #define AT91_ADC_CDR0_9X5	(0x50)			/* Channel Data Register 0 for 9X5 */
>  
> +#define AT91_ADC_ACR		0x94	/* Analog Control Register */
> +#define		AT91_ADC_ACR_PENDETSENS	(0x3 << 0)	/* pull-up resistor */
> +
> +#define AT91_ADC_TSMR		0xB0
> +#define		AT91_ADC_TSMR_TSMODE	(3 << 0)	/* Touch Screen Mode */
> +#define			AT91_ADC_TSMR_TSMODE_NONE		(0 << 0)
> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_NO_PRESS	(1 << 0)
> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_PRESS	(2 << 0)
> +#define			AT91_ADC_TSMR_TSMODE_5WIRE		(3 << 0)
> +#define		AT91_ADC_TSMR_TSAV	(3 << 4)	/* Averages samples */
> +#define			AT91_ADC_TSMR_TSAV_(x)		((x) << 4)
> +#define		AT91_ADC_TSMR_SCTIM	(0x0f << 16)	/* Switch closure time */
> +#define		AT91_ADC_TSMR_PENDBC	(0x0f << 28)	/* Pen Debounce time */
> +#define			AT91_ADC_TSMR_PENDBC_(x)	((x) << 28)
> +#define		AT91_ADC_TSMR_NOTSDMA	(1 << 22)	/* No Touchscreen DMA */
> +#define		AT91_ADC_TSMR_PENDET_DIS	(0 << 24)	/* Pen contact detection disable */
> +#define		AT91_ADC_TSMR_PENDET_ENA	(1 << 24)	/* Pen contact detection enable */
> +
> +#define AT91_ADC_TSXPOSR	0xB4
> +#define AT91_ADC_TSYPOSR	0xB8
> +#define AT91_ADC_TSPRESSR	0xBC
> +
>  #define AT91_ADC_TRGR_9260	AT91_ADC_MR
>  #define AT91_ADC_TRGR_9G45	0x08
>  #define AT91_ADC_TRGR_9X5	0xC0
>  
> +/* Trigger Register bit field */
> +#define		AT91_ADC_TRGR_TRGPER	(0xffff << 16)
> +#define			AT91_ADC_TRGR_TRGPER_(x)	((x) << 16)
> +#define		AT91_ADC_TRGR_TRGMOD	(0x7 << 0)
> +#define			AT91_ADC_TRGR_MOD_PERIOD_TRIG	(5 << 0)
> +
>  #endif
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index 22cf61d2..68ddd7f 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -11,6 +11,7 @@
>  #include <linux/clk.h>
>  #include <linux/err.h>
>  #include <linux/io.h>
> +#include <linux/input.h>
>  #include <linux/interrupt.h>
>  #include <linux/jiffies.h>
>  #include <linux/kernel.h>
> @@ -39,7 +40,23 @@
>  #define at91_adc_writel(st, reg, val) \
>  	(writel_relaxed(val, st->reg_base + reg))
>  
> +#define DRIVER_NAME		"at91_adc"
> +#define MAX_POS_BITS		12
> +
> +#define TOUCH_SAMPLE_PERIOD_US		2000	/* 2ms */
> +#define TOUCH_PEN_DETECT_DEBOUNCE_US	200
> +
>  struct at91_adc_caps {
> +	bool	has_ts;		/* Support touch screen */
> +	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
> +	/*
> +	 * Numbers of sampling data will be averaged. Can be 0~3.
> +	 * Hardware can average (2 ^ ts_filter_average) sample data.
> +	 */
> +	u8	ts_filter_average;
> +	/* Pen Detection input pull-up resistor, can be 0~3 */
> +	u8	ts_pen_detect_sensitivity;
> +
>  	/* startup time calculate function */
>  	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
>  
> @@ -47,6 +64,12 @@ struct at91_adc_caps {
>  	struct at91_adc_reg_desc registers;
>  };
>  
> +enum atmel_adc_ts_type {
> +	ATMEL_ADC_TOUCHSCREEN_NONE = 0,
> +	ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
> +	ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
> +};
> +
>  struct at91_adc_state {
>  	struct clk		*adc_clk;
>  	u16			*buffer;
> @@ -71,6 +94,26 @@ struct at91_adc_state {
>  	bool			low_res;	/* the resolution corresponds to the lowest one */
>  	wait_queue_head_t	wq_data_avail;
>  	struct at91_adc_caps	*caps;
> +
> +	/*
> +	 * Following ADC channels are shared by touchscreen:
> +	 *
> +	 * CH0 -- Touch screen XP/UL
> +	 * CH1 -- Touch screen XM/UR
> +	 * CH2 -- Touch screen YP/LL
> +	 * CH3 -- Touch screen YM/Sense
> +	 * CH4 -- Touch screen LR(5-wire only)
> +	 *
> +	 * The bitfields below represents the reserved channel in the
> +	 * touchscreen mode.
> +	 */
> +#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 0)
> +#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 0)
> +	enum atmel_adc_ts_type	touchscreen_type;
> +	struct input_dev	*ts_input;
> +
> +	u16			ts_sample_period_val;
> +	u32			ts_pressure_threshold;
>  };
>  
>  static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
> @@ -105,14 +148,10 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
>  	return IRQ_HANDLED;
>  }
>  
> -static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
> +/* Handler for classic adc channel eoc trigger */
> +void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
>  {
> -	struct iio_dev *idev = private;
>  	struct at91_adc_state *st = iio_priv(idev);
> -	u32 status = at91_adc_readl(st, st->registers->status_register);
> -
> -	if (!(status & st->registers->drdy_mask))
> -		return IRQ_HANDLED;
>  
>  	if (iio_buffer_enabled(idev)) {
>  		disable_irq_nosync(irq);
> @@ -122,6 +161,115 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
>  		st->done = true;
>  		wake_up_interruptible(&st->wq_data_avail);
>  	}
> +}
> +
> +static int at91_ts_sample(struct at91_adc_state *st)
> +{
> +	unsigned int xscale, yscale, reg, z1, z2;
> +	unsigned int x, y, pres, xpos, ypos;
> +	unsigned int rxp = 1;
> +	unsigned int factor = 1000;
> +	struct iio_dev *idev = iio_priv_to_dev(st);
> +
> +	unsigned int xyz_mask_bits = st->res;
> +	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
> +
> +	/* calculate position */
> +	/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
> +	reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
> +	xpos = reg & xyz_mask;
> +	x = (xpos << MAX_POS_BITS) - xpos;
> +	xscale = (reg >> 16) & xyz_mask;
> +	if (xscale == 0) {
> +		dev_err(&idev->dev, "Error: xscale == 0!\n");
> +		return -1;
> +	}
> +	x /= xscale;
> +
> +	/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
> +	reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
> +	ypos = reg & xyz_mask;
> +	y = (ypos << MAX_POS_BITS) - ypos;
> +	yscale = (reg >> 16) & xyz_mask;
> +	if (yscale == 0) {
> +		dev_err(&idev->dev, "Error: yscale == 0!\n");
> +		return -1;
> +	}
> +	y /= yscale;
> +
> +	/* calculate the pressure */
> +	reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
> +	z1 = reg & xyz_mask;
> +	z2 = (reg >> 16) & xyz_mask;
> +
> +	if (z1 != 0)
> +		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
> +			/ factor;
> +	else
> +		pres = st->ts_pressure_threshold;	/* no pen contacted */
> +
> +	dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
> +				xpos, xscale, ypos, yscale, z1, z2, pres);
> +
> +	if (pres < st->ts_pressure_threshold) {
> +		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
> +					x, y, pres / factor);
> +		input_report_abs(st->ts_input, ABS_X, x);
> +		input_report_abs(st->ts_input, ABS_Y, y);
> +		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
> +		input_report_key(st->ts_input, BTN_TOUCH, 1);
> +		input_sync(st->ts_input);
> +	} else {
> +		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
> +	}
> +
> +	return 0;
> +}
> +
> +static irqreturn_t at91_adc_interrupt(int irq, void *private)
> +{
> +	struct iio_dev *idev = private;
> +	struct at91_adc_state *st = iio_priv(idev);
> +	u32 status = at91_adc_readl(st, st->registers->status_register);
> +	const uint32_t ts_data_irq_mask =
> +		AT91_ADC_IER_XRDY |
> +		AT91_ADC_IER_YRDY |
> +		AT91_ADC_IER_PRDY;
> +
> +	if (status & st->registers->drdy_mask)
> +		handle_adc_eoc_trigger(irq, idev);
> +
> +	if (status & AT91_ADC_IER_PEN) {
> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
> +			ts_data_irq_mask);
> +		/* Set up period trigger for sampling */
> +		at91_adc_writel(st, st->registers->trigger_register,
> +			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
> +			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
> +	} else if (status & AT91_ADC_IER_NOPEN) {
> +		at91_adc_writel(st, st->registers->trigger_register, 0);
> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
> +			ts_data_irq_mask);
> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
> +
> +		input_report_key(st->ts_input, BTN_TOUCH, 0);
> +		input_sync(st->ts_input);
> +	} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
> +		/* Now all touchscreen data is ready */
> +
> +		if (status & AT91_ADC_ISR_PENS) {
> +			/* validate data by pen contact */
> +			at91_ts_sample(st);
> +		} else {
> +			/* triggered by event that is no pen contact, just read
> +			 * them to clean the interrupt and discard all.
> +			 */
> +			at91_adc_readl(st, AT91_ADC_TSXPOSR);
> +			at91_adc_readl(st, AT91_ADC_TSYPOSR);
> +			at91_adc_readl(st, AT91_ADC_TSPRESSR);
> +		}
> +	}
>  
>  	return IRQ_HANDLED;
>  }
> @@ -131,6 +279,16 @@ static int at91_adc_channel_init(struct iio_dev *idev)
>  	struct at91_adc_state *st = iio_priv(idev);
>  	struct iio_chan_spec *chan_array, *timestamp;
>  	int bit, idx = 0;
> +	unsigned long rsvd_mask = 0;
> +
> +	/* If touchscreen is enable, then reserve the adc channels */
> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
> +	else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
> +
> +	/* set up the channel mask to reserve touchscreen channels */
> +	st->channels_mask &= ~rsvd_mask;
>  
>  	idev->num_channels = bitmap_weight(&st->channels_mask,
>  					   st->num_channels) + 1;
> @@ -479,6 +637,39 @@ static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
>  
>  static const struct of_device_id at91_adc_dt_ids[];
>  
> +static int at91_adc_probe_dt_ts(struct device_node *node,
> +	struct at91_adc_state *st, struct device *dev)
> +{
> +	int ret;
> +	u32 prop;
> +
> +	ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
> +	if (ret) {
> +		dev_info(dev, "ADC Touch screen is disabled.\n");
> +		return 0;
> +	}
> +
> +	switch (prop) {
> +	case 4:
> +	case 5:
> +		st->touchscreen_type = prop;
> +		break;
> +	default:
> +		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
> +		return -EINVAL;
> +	}
> +
> +	prop = 0;
> +	of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
> +	st->ts_pressure_threshold = prop;
> +	if (st->ts_pressure_threshold) {
> +		return 0;
> +	} else {
> +		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
> +		return -EINVAL;
> +	}
> +}
> +
>  static int at91_adc_probe_dt(struct at91_adc_state *st,
>  			     struct platform_device *pdev)
>  {
> @@ -560,6 +751,12 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
>  		i++;
>  	}
>  
> +	/* Check if touchscreen is supported. */
> +	if (st->caps->has_ts)
> +		return at91_adc_probe_dt_ts(node, st, &idev->dev);
> +	else
> +		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
> +
>  	return 0;
>  
>  error_ret:
> @@ -591,6 +788,114 @@ static const struct iio_info at91_adc_info = {
>  	.read_raw = &at91_adc_read_raw,
>  };
>  
> +/* Touchscreen related functions */
> +static int atmel_ts_open(struct input_dev *dev)
> +{
> +	struct at91_adc_state *st = input_get_drvdata(dev);
> +
> +	at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
> +	return 0;
> +}
> +
> +static void atmel_ts_close(struct input_dev *dev)
> +{
> +	struct at91_adc_state *st = input_get_drvdata(dev);
> +
> +	at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
> +}
> +
> +static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
> +{
> +	u32 reg = 0, pendbc;
> +	int i = 0;
> +
> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
> +		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
> +	else
> +		reg = AT91_ADC_TSMR_TSMODE_5WIRE;
> +
> +	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
> +	 * pen detect noise.
> +	 * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
> +	 */
> +	pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);
> +
> +	while (pendbc >> ++i)
> +		;	/* Empty! Find the shift offset */
> +	if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
> +		pendbc = i;
> +	else
> +		pendbc = i - 1;
> +
> +	if (st->caps->has_tsmr) {
> +		reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
> +				& AT91_ADC_TSMR_TSAV;
> +		reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
> +		reg |= AT91_ADC_TSMR_NOTSDMA;
> +		reg |= AT91_ADC_TSMR_PENDET_ENA;
> +		reg |= 0x03 << 8;	/* TSFREQ, need bigger than TSAV */
> +
> +		at91_adc_writel(st, AT91_ADC_TSMR, reg);
> +	} else {
> +		/* TODO: for 9g45 which has no TSMR */
> +	}
> +
> +	/* Change adc internal resistor value for better pen detection,
> +	 * default value is 100 kOhm.
> +	 * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
> +	 * option only available on ES2 and higher
> +	 */
> +	at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
> +			& AT91_ADC_ACR_PENDETSENS);
> +
> +	/* Sample Peroid Time = (TRGPER + 1) / ADCClock */
> +	st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
> +			adc_clk_khz / 1000) - 1, 1);
> +
> +	return 0;
> +}
> +
> +static int at91_ts_register(struct at91_adc_state *st,
> +		struct platform_device *pdev)
> +{
> +	struct input_dev *input;
> +	struct iio_dev *idev = iio_priv_to_dev(st);
> +	int ret;
> +
> +	input = input_allocate_device();
> +	if (!input) {
> +		dev_err(&idev->dev, "Failed to allocate TS device!\n");
> +		return -ENOMEM;
> +	}
> +
> +	input->name = DRIVER_NAME;
> +	input->id.bustype = BUS_HOST;
> +	input->dev.parent = &pdev->dev;
> +	input->open = atmel_ts_open;
> +	input->close = atmel_ts_close;
> +
> +	__set_bit(EV_ABS, input->evbit);
> +	__set_bit(EV_KEY, input->evbit);
> +	__set_bit(BTN_TOUCH, input->keybit);
> +	input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
> +	input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
> +	input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
> +
> +	st->ts_input = input;
> +	input_set_drvdata(input, st);
> +
> +	ret = input_register_device(input);
> +	if (ret)
> +		input_free_device(st->ts_input);
> +
> +	return ret;
> +}
> +
> +static void at91_ts_unregister(struct at91_adc_state *st)
> +{
> +	input_unregister_device(st->ts_input);
> +}
> +
>  static int at91_adc_probe(struct platform_device *pdev)
>  {
>  	unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
> @@ -642,7 +947,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
>  	at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
>  	ret = request_irq(st->irq,
> -			  at91_adc_eoc_trigger,
> +			  at91_adc_interrupt,
>  			  0,
>  			  pdev->dev.driver->name,
>  			  idev);
> @@ -687,6 +992,10 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	mstrclk = clk_get_rate(st->clk);
>  	adc_clk = clk_get_rate(st->adc_clk);
>  	adc_clk_khz = adc_clk / 1000;
> +
> +	dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
> +		mstrclk, adc_clk);
> +
>  	prsc = (mstrclk / (2 * adc_clk)) - 1;
>  
>  	if (!st->startup_time) {
> @@ -723,30 +1032,52 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	init_waitqueue_head(&st->wq_data_avail);
>  	mutex_init(&st->lock);
>  
> -	ret = at91_adc_buffer_init(idev);
> -	if (ret < 0) {
> -		dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
> -		goto error_disable_adc_clk;
> -	}
> +	/*
> +	 * Since touch screen will set trigger register as period trigger. So
> +	 * when touch screen is enabled, then we have to disable hardware
> +	 * trigger for classic adc.
> +	 */
> +	if (!st->touchscreen_type) {
> +		ret = at91_adc_buffer_init(idev);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
> +			goto error_disable_adc_clk;
> +		}
>  
> -	ret = at91_adc_trigger_init(idev);
> -	if (ret < 0) {
> -		dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
> -		goto error_unregister_buffer;
> +		ret = at91_adc_trigger_init(idev);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
> +			at91_adc_buffer_remove(idev);
> +			goto error_disable_adc_clk;
> +		}
> +	} else {
> +		if (!st->caps->has_tsmr) {
> +			dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
> +			goto error_disable_adc_clk;
> +		}
> +
> +		ret = at91_ts_register(st, pdev);
> +		if (ret)
> +			goto error_disable_adc_clk;
> +
> +		at91_ts_hw_init(st, adc_clk_khz);
>  	}
>  
>  	ret = iio_device_register(idev);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "Couldn't register the device.\n");
> -		goto error_remove_triggers;
> +		goto error_iio_device_register;
>  	}
>  
>  	return 0;
>  
> -error_remove_triggers:
> -	at91_adc_trigger_remove(idev);
> -error_unregister_buffer:
> -	at91_adc_buffer_remove(idev);
> +error_iio_device_register:
> +	if (!st->touchscreen_type) {
> +		at91_adc_trigger_remove(idev);
> +		at91_adc_buffer_remove(idev);
> +	} else {
> +		at91_ts_unregister(st);
> +	}
>  error_disable_adc_clk:
>  	clk_disable_unprepare(st->adc_clk);
>  error_disable_clk:
> @@ -762,8 +1093,12 @@ static int at91_adc_remove(struct platform_device *pdev)
>  	struct at91_adc_state *st = iio_priv(idev);
>  
>  	iio_device_unregister(idev);
> -	at91_adc_trigger_remove(idev);
> -	at91_adc_buffer_remove(idev);
> +	if (!st->touchscreen_type) {
> +		at91_adc_trigger_remove(idev);
> +		at91_adc_buffer_remove(idev);
> +	} else {
> +		at91_ts_unregister(st);
> +	}
>  	clk_disable_unprepare(st->adc_clk);
>  	clk_disable_unprepare(st->clk);
>  	free_irq(st->irq, idev);
> @@ -786,6 +1121,7 @@ static struct at91_adc_caps at91sam9260_caps = {
>  };
>  
>  static struct at91_adc_caps at91sam9g45_caps = {
> +	.has_ts = true,
>  	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
>  	.num_channels = 8,
>  	.registers = {
> @@ -799,6 +1135,10 @@ static struct at91_adc_caps at91sam9g45_caps = {
>  };
>  
>  static struct at91_adc_caps at91sam9x5_caps = {
> +	.has_ts = true,
> +	.has_tsmr = true,
> +	.ts_filter_average = 3,
> +	.ts_pen_detect_sensitivity = 2,
>  	.calc_startup_ticks = calc_startup_ticks_9x5,
>  	.num_channels = 12,
>  	.registers = {
> @@ -825,7 +1165,7 @@ static struct platform_driver at91_adc_driver = {
>  	.probe = at91_adc_probe,
>  	.remove = at91_adc_remove,
>  	.driver = {
> -		   .name = "at91_adc",
> +		   .name = DRIVER_NAME,
>  		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
>  	},
>  };
> -- 
> 1.7.9.5
> 

-- 
Dmitry

Re: [PATCH 3/3] iio: at91: introduce touch screen support in iio adc driver

[Jonathan Cameron]

On 10/17/13 18:18, Dmitry Torokhov wrote:
> Hi Josh,
> 
> On Tue, Oct 08, 2013 at 11:48:56AM +0800, Josh Wu wrote:
>> AT91 ADC hardware integrate touch screen support. So this patch add touch
>> screen support for at91 adc iio driver.
>> To enable touch screen support in adc, you need to add the dt parameters:
>>   1. which type of touch are used? (4 or 5 wires), sample period time.
>>   2. correct pressure detect threshold value.
>>
>> In the meantime, since touch screen will use a interal period trigger of adc,
>> so it is conflict to other hardware triggers. Driver will disable the hardware
>> trigger support if touch screen is enabled.
>>
>> This driver has been tested in AT91SAM9X5-EK and SAMA5D3x-EK.
>>
>> Signed-off-by: Josh Wu <josh.wu@atmel.com>
>> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>> CC: devicetree@vger.kernel.org
> 
> Input stuff looks reasonable to me.
> 
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Whilst I am still not entirely happy that this driver isn't an mfd
with the two parts nicely separately, I have applied this to the togreg
branch of

git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git

Thanks for all your hard work on this Josh.

Jonathan

> 
>> ---
>>  .../devicetree/bindings/arm/atmel-adc.txt          |    7 +
>>  arch/arm/mach-at91/include/mach/at91_adc.h         |   34 ++
>>  drivers/iio/adc/at91_adc.c                         |  388 ++++++++++++++++++--
>>  3 files changed, 405 insertions(+), 24 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/arm/atmel-adc.txt b/Documentation/devicetree/bindings/arm/atmel-adc.txt
>> index 0e65e01..d106146 100644
>> --- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
>> +++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
>> @@ -23,6 +23,13 @@ Optional properties:
>>  		       resolution will be used.
>>    - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
>>    - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
>> +  - atmel,adc-ts-wires: Number of touch screen wires. Should be 4 or 5. If this
>> +                        value is set, then adc driver will enable touch screen
>> +                        support.
>> +    NOTE: when adc touch screen enabled, the adc hardware trigger will be
>> +          disabled. Since touch screen will occupied the trigger register.
>> +  - atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
>> +                                     make touch detect more precision.
>>   
>>  Optional trigger Nodes:
>>    - Required properties:
>> diff --git a/arch/arm/mach-at91/include/mach/at91_adc.h b/arch/arm/mach-at91/include/mach/at91_adc.h
>> index 048a57f..c287307 100644
>> --- a/arch/arm/mach-at91/include/mach/at91_adc.h
>> +++ b/arch/arm/mach-at91/include/mach/at91_adc.h
>> @@ -60,14 +60,48 @@
>>  #define AT91_ADC_IER		0x24		/* Interrupt Enable Register */
>>  #define AT91_ADC_IDR		0x28		/* Interrupt Disable Register */
>>  #define AT91_ADC_IMR		0x2C		/* Interrupt Mask Register */
>> +#define		AT91_ADC_IER_PEN	(1 << 29)
>> +#define		AT91_ADC_IER_NOPEN	(1 << 30)
>> +#define		AT91_ADC_IER_XRDY	(1 << 20)
>> +#define		AT91_ADC_IER_YRDY	(1 << 21)
>> +#define		AT91_ADC_IER_PRDY	(1 << 22)
>> +#define		AT91_ADC_ISR_PENS	(1 << 31)
>>  
>>  #define AT91_ADC_CHR(n)		(0x30 + ((n) * 4))	/* Channel Data Register N */
>>  #define		AT91_ADC_DATA		(0x3ff)
>>  
>>  #define AT91_ADC_CDR0_9X5	(0x50)			/* Channel Data Register 0 for 9X5 */
>>  
>> +#define AT91_ADC_ACR		0x94	/* Analog Control Register */
>> +#define		AT91_ADC_ACR_PENDETSENS	(0x3 << 0)	/* pull-up resistor */
>> +
>> +#define AT91_ADC_TSMR		0xB0
>> +#define		AT91_ADC_TSMR_TSMODE	(3 << 0)	/* Touch Screen Mode */
>> +#define			AT91_ADC_TSMR_TSMODE_NONE		(0 << 0)
>> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_NO_PRESS	(1 << 0)
>> +#define			AT91_ADC_TSMR_TSMODE_4WIRE_PRESS	(2 << 0)
>> +#define			AT91_ADC_TSMR_TSMODE_5WIRE		(3 << 0)
>> +#define		AT91_ADC_TSMR_TSAV	(3 << 4)	/* Averages samples */
>> +#define			AT91_ADC_TSMR_TSAV_(x)		((x) << 4)
>> +#define		AT91_ADC_TSMR_SCTIM	(0x0f << 16)	/* Switch closure time */
>> +#define		AT91_ADC_TSMR_PENDBC	(0x0f << 28)	/* Pen Debounce time */
>> +#define			AT91_ADC_TSMR_PENDBC_(x)	((x) << 28)
>> +#define		AT91_ADC_TSMR_NOTSDMA	(1 << 22)	/* No Touchscreen DMA */
>> +#define		AT91_ADC_TSMR_PENDET_DIS	(0 << 24)	/* Pen contact detection disable */
>> +#define		AT91_ADC_TSMR_PENDET_ENA	(1 << 24)	/* Pen contact detection enable */
>> +
>> +#define AT91_ADC_TSXPOSR	0xB4
>> +#define AT91_ADC_TSYPOSR	0xB8
>> +#define AT91_ADC_TSPRESSR	0xBC
>> +
>>  #define AT91_ADC_TRGR_9260	AT91_ADC_MR
>>  #define AT91_ADC_TRGR_9G45	0x08
>>  #define AT91_ADC_TRGR_9X5	0xC0
>>  
>> +/* Trigger Register bit field */
>> +#define		AT91_ADC_TRGR_TRGPER	(0xffff << 16)
>> +#define			AT91_ADC_TRGR_TRGPER_(x)	((x) << 16)
>> +#define		AT91_ADC_TRGR_TRGMOD	(0x7 << 0)
>> +#define			AT91_ADC_TRGR_MOD_PERIOD_TRIG	(5 << 0)
>> +
>>  #endif
>> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
>> index 22cf61d2..68ddd7f 100644
>> --- a/drivers/iio/adc/at91_adc.c
>> +++ b/drivers/iio/adc/at91_adc.c
>> @@ -11,6 +11,7 @@
>>  #include <linux/clk.h>
>>  #include <linux/err.h>
>>  #include <linux/io.h>
>> +#include <linux/input.h>
>>  #include <linux/interrupt.h>
>>  #include <linux/jiffies.h>
>>  #include <linux/kernel.h>
>> @@ -39,7 +40,23 @@
>>  #define at91_adc_writel(st, reg, val) \
>>  	(writel_relaxed(val, st->reg_base + reg))
>>  
>> +#define DRIVER_NAME		"at91_adc"
>> +#define MAX_POS_BITS		12
>> +
>> +#define TOUCH_SAMPLE_PERIOD_US		2000	/* 2ms */
>> +#define TOUCH_PEN_DETECT_DEBOUNCE_US	200
>> +
>>  struct at91_adc_caps {
>> +	bool	has_ts;		/* Support touch screen */
>> +	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
>> +	/*
>> +	 * Numbers of sampling data will be averaged. Can be 0~3.
>> +	 * Hardware can average (2 ^ ts_filter_average) sample data.
>> +	 */
>> +	u8	ts_filter_average;
>> +	/* Pen Detection input pull-up resistor, can be 0~3 */
>> +	u8	ts_pen_detect_sensitivity;
>> +
>>  	/* startup time calculate function */
>>  	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
>>  
>> @@ -47,6 +64,12 @@ struct at91_adc_caps {
>>  	struct at91_adc_reg_desc registers;
>>  };
>>  
>> +enum atmel_adc_ts_type {
>> +	ATMEL_ADC_TOUCHSCREEN_NONE = 0,
>> +	ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
>> +	ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
>> +};
>> +
>>  struct at91_adc_state {
>>  	struct clk		*adc_clk;
>>  	u16			*buffer;
>> @@ -71,6 +94,26 @@ struct at91_adc_state {
>>  	bool			low_res;	/* the resolution corresponds to the lowest one */
>>  	wait_queue_head_t	wq_data_avail;
>>  	struct at91_adc_caps	*caps;
>> +
>> +	/*
>> +	 * Following ADC channels are shared by touchscreen:
>> +	 *
>> +	 * CH0 -- Touch screen XP/UL
>> +	 * CH1 -- Touch screen XM/UR
>> +	 * CH2 -- Touch screen YP/LL
>> +	 * CH3 -- Touch screen YM/Sense
>> +	 * CH4 -- Touch screen LR(5-wire only)
>> +	 *
>> +	 * The bitfields below represents the reserved channel in the
>> +	 * touchscreen mode.
>> +	 */
>> +#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 0)
>> +#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 0)
>> +	enum atmel_adc_ts_type	touchscreen_type;
>> +	struct input_dev	*ts_input;
>> +
>> +	u16			ts_sample_period_val;
>> +	u32			ts_pressure_threshold;
>>  };
>>  
>>  static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
>> @@ -105,14 +148,10 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
>>  	return IRQ_HANDLED;
>>  }
>>  
>> -static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
>> +/* Handler for classic adc channel eoc trigger */
>> +void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
>>  {
>> -	struct iio_dev *idev = private;
>>  	struct at91_adc_state *st = iio_priv(idev);
>> -	u32 status = at91_adc_readl(st, st->registers->status_register);
>> -
>> -	if (!(status & st->registers->drdy_mask))
>> -		return IRQ_HANDLED;
>>  
>>  	if (iio_buffer_enabled(idev)) {
>>  		disable_irq_nosync(irq);
>> @@ -122,6 +161,115 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
>>  		st->done = true;
>>  		wake_up_interruptible(&st->wq_data_avail);
>>  	}
>> +}
>> +
>> +static int at91_ts_sample(struct at91_adc_state *st)
>> +{
>> +	unsigned int xscale, yscale, reg, z1, z2;
>> +	unsigned int x, y, pres, xpos, ypos;
>> +	unsigned int rxp = 1;
>> +	unsigned int factor = 1000;
>> +	struct iio_dev *idev = iio_priv_to_dev(st);
>> +
>> +	unsigned int xyz_mask_bits = st->res;
>> +	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
>> +
>> +	/* calculate position */
>> +	/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
>> +	reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
>> +	xpos = reg & xyz_mask;
>> +	x = (xpos << MAX_POS_BITS) - xpos;
>> +	xscale = (reg >> 16) & xyz_mask;
>> +	if (xscale == 0) {
>> +		dev_err(&idev->dev, "Error: xscale == 0!\n");
>> +		return -1;
>> +	}
>> +	x /= xscale;
>> +
>> +	/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
>> +	reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
>> +	ypos = reg & xyz_mask;
>> +	y = (ypos << MAX_POS_BITS) - ypos;
>> +	yscale = (reg >> 16) & xyz_mask;
>> +	if (yscale == 0) {
>> +		dev_err(&idev->dev, "Error: yscale == 0!\n");
>> +		return -1;
>> +	}
>> +	y /= yscale;
>> +
>> +	/* calculate the pressure */
>> +	reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
>> +	z1 = reg & xyz_mask;
>> +	z2 = (reg >> 16) & xyz_mask;
>> +
>> +	if (z1 != 0)
>> +		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
>> +			/ factor;
>> +	else
>> +		pres = st->ts_pressure_threshold;	/* no pen contacted */
>> +
>> +	dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
>> +				xpos, xscale, ypos, yscale, z1, z2, pres);
>> +
>> +	if (pres < st->ts_pressure_threshold) {
>> +		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
>> +					x, y, pres / factor);
>> +		input_report_abs(st->ts_input, ABS_X, x);
>> +		input_report_abs(st->ts_input, ABS_Y, y);
>> +		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
>> +		input_report_key(st->ts_input, BTN_TOUCH, 1);
>> +		input_sync(st->ts_input);
>> +	} else {
>> +		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static irqreturn_t at91_adc_interrupt(int irq, void *private)
>> +{
>> +	struct iio_dev *idev = private;
>> +	struct at91_adc_state *st = iio_priv(idev);
>> +	u32 status = at91_adc_readl(st, st->registers->status_register);
>> +	const uint32_t ts_data_irq_mask =
>> +		AT91_ADC_IER_XRDY |
>> +		AT91_ADC_IER_YRDY |
>> +		AT91_ADC_IER_PRDY;
>> +
>> +	if (status & st->registers->drdy_mask)
>> +		handle_adc_eoc_trigger(irq, idev);
>> +
>> +	if (status & AT91_ADC_IER_PEN) {
>> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
>> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
>> +			ts_data_irq_mask);
>> +		/* Set up period trigger for sampling */
>> +		at91_adc_writel(st, st->registers->trigger_register,
>> +			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
>> +			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
>> +	} else if (status & AT91_ADC_IER_NOPEN) {
>> +		at91_adc_writel(st, st->registers->trigger_register, 0);
>> +		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
>> +			ts_data_irq_mask);
>> +		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
>> +
>> +		input_report_key(st->ts_input, BTN_TOUCH, 0);
>> +		input_sync(st->ts_input);
>> +	} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
>> +		/* Now all touchscreen data is ready */
>> +
>> +		if (status & AT91_ADC_ISR_PENS) {
>> +			/* validate data by pen contact */
>> +			at91_ts_sample(st);
>> +		} else {
>> +			/* triggered by event that is no pen contact, just read
>> +			 * them to clean the interrupt and discard all.
>> +			 */
>> +			at91_adc_readl(st, AT91_ADC_TSXPOSR);
>> +			at91_adc_readl(st, AT91_ADC_TSYPOSR);
>> +			at91_adc_readl(st, AT91_ADC_TSPRESSR);
>> +		}
>> +	}
>>  
>>  	return IRQ_HANDLED;
>>  }
>> @@ -131,6 +279,16 @@ static int at91_adc_channel_init(struct iio_dev *idev)
>>  	struct at91_adc_state *st = iio_priv(idev);
>>  	struct iio_chan_spec *chan_array, *timestamp;
>>  	int bit, idx = 0;
>> +	unsigned long rsvd_mask = 0;
>> +
>> +	/* If touchscreen is enable, then reserve the adc channels */
>> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
>> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
>> +	else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
>> +		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
>> +
>> +	/* set up the channel mask to reserve touchscreen channels */
>> +	st->channels_mask &= ~rsvd_mask;
>>  
>>  	idev->num_channels = bitmap_weight(&st->channels_mask,
>>  					   st->num_channels) + 1;
>> @@ -479,6 +637,39 @@ static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
>>  
>>  static const struct of_device_id at91_adc_dt_ids[];
>>  
>> +static int at91_adc_probe_dt_ts(struct device_node *node,
>> +	struct at91_adc_state *st, struct device *dev)
>> +{
>> +	int ret;
>> +	u32 prop;
>> +
>> +	ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
>> +	if (ret) {
>> +		dev_info(dev, "ADC Touch screen is disabled.\n");
>> +		return 0;
>> +	}
>> +
>> +	switch (prop) {
>> +	case 4:
>> +	case 5:
>> +		st->touchscreen_type = prop;
>> +		break;
>> +	default:
>> +		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
>> +		return -EINVAL;
>> +	}
>> +
>> +	prop = 0;
>> +	of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
>> +	st->ts_pressure_threshold = prop;
>> +	if (st->ts_pressure_threshold) {
>> +		return 0;
>> +	} else {
>> +		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>>  static int at91_adc_probe_dt(struct at91_adc_state *st,
>>  			     struct platform_device *pdev)
>>  {
>> @@ -560,6 +751,12 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
>>  		i++;
>>  	}
>>  
>> +	/* Check if touchscreen is supported. */
>> +	if (st->caps->has_ts)
>> +		return at91_adc_probe_dt_ts(node, st, &idev->dev);
>> +	else
>> +		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
>> +
>>  	return 0;
>>  
>>  error_ret:
>> @@ -591,6 +788,114 @@ static const struct iio_info at91_adc_info = {
>>  	.read_raw = &at91_adc_read_raw,
>>  };
>>  
>> +/* Touchscreen related functions */
>> +static int atmel_ts_open(struct input_dev *dev)
>> +{
>> +	struct at91_adc_state *st = input_get_drvdata(dev);
>> +
>> +	at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
>> +	return 0;
>> +}
>> +
>> +static void atmel_ts_close(struct input_dev *dev)
>> +{
>> +	struct at91_adc_state *st = input_get_drvdata(dev);
>> +
>> +	at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
>> +}
>> +
>> +static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
>> +{
>> +	u32 reg = 0, pendbc;
>> +	int i = 0;
>> +
>> +	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
>> +		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
>> +	else
>> +		reg = AT91_ADC_TSMR_TSMODE_5WIRE;
>> +
>> +	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
>> +	 * pen detect noise.
>> +	 * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
>> +	 */
>> +	pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);
>> +
>> +	while (pendbc >> ++i)
>> +		;	/* Empty! Find the shift offset */
>> +	if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
>> +		pendbc = i;
>> +	else
>> +		pendbc = i - 1;
>> +
>> +	if (st->caps->has_tsmr) {
>> +		reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
>> +				& AT91_ADC_TSMR_TSAV;
>> +		reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
>> +		reg |= AT91_ADC_TSMR_NOTSDMA;
>> +		reg |= AT91_ADC_TSMR_PENDET_ENA;
>> +		reg |= 0x03 << 8;	/* TSFREQ, need bigger than TSAV */
>> +
>> +		at91_adc_writel(st, AT91_ADC_TSMR, reg);
>> +	} else {
>> +		/* TODO: for 9g45 which has no TSMR */
>> +	}
>> +
>> +	/* Change adc internal resistor value for better pen detection,
>> +	 * default value is 100 kOhm.
>> +	 * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
>> +	 * option only available on ES2 and higher
>> +	 */
>> +	at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
>> +			& AT91_ADC_ACR_PENDETSENS);
>> +
>> +	/* Sample Peroid Time = (TRGPER + 1) / ADCClock */
>> +	st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
>> +			adc_clk_khz / 1000) - 1, 1);
>> +
>> +	return 0;
>> +}
>> +
>> +static int at91_ts_register(struct at91_adc_state *st,
>> +		struct platform_device *pdev)
>> +{
>> +	struct input_dev *input;
>> +	struct iio_dev *idev = iio_priv_to_dev(st);
>> +	int ret;
>> +
>> +	input = input_allocate_device();
>> +	if (!input) {
>> +		dev_err(&idev->dev, "Failed to allocate TS device!\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	input->name = DRIVER_NAME;
>> +	input->id.bustype = BUS_HOST;
>> +	input->dev.parent = &pdev->dev;
>> +	input->open = atmel_ts_open;
>> +	input->close = atmel_ts_close;
>> +
>> +	__set_bit(EV_ABS, input->evbit);
>> +	__set_bit(EV_KEY, input->evbit);
>> +	__set_bit(BTN_TOUCH, input->keybit);
>> +	input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
>> +	input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
>> +	input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
>> +
>> +	st->ts_input = input;
>> +	input_set_drvdata(input, st);
>> +
>> +	ret = input_register_device(input);
>> +	if (ret)
>> +		input_free_device(st->ts_input);
>> +
>> +	return ret;
>> +}
>> +
>> +static void at91_ts_unregister(struct at91_adc_state *st)
>> +{
>> +	input_unregister_device(st->ts_input);
>> +}
>> +
>>  static int at91_adc_probe(struct platform_device *pdev)
>>  {
>>  	unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
>> @@ -642,7 +947,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>>  	at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
>>  	at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
>>  	ret = request_irq(st->irq,
>> -			  at91_adc_eoc_trigger,
>> +			  at91_adc_interrupt,
>>  			  0,
>>  			  pdev->dev.driver->name,
>>  			  idev);
>> @@ -687,6 +992,10 @@ static int at91_adc_probe(struct platform_device *pdev)
>>  	mstrclk = clk_get_rate(st->clk);
>>  	adc_clk = clk_get_rate(st->adc_clk);
>>  	adc_clk_khz = adc_clk / 1000;
>> +
>> +	dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
>> +		mstrclk, adc_clk);
>> +
>>  	prsc = (mstrclk / (2 * adc_clk)) - 1;
>>  
>>  	if (!st->startup_time) {
>> @@ -723,30 +1032,52 @@ static int at91_adc_probe(struct platform_device *pdev)
>>  	init_waitqueue_head(&st->wq_data_avail);
>>  	mutex_init(&st->lock);
>>  
>> -	ret = at91_adc_buffer_init(idev);
>> -	if (ret < 0) {
>> -		dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
>> -		goto error_disable_adc_clk;
>> -	}
>> +	/*
>> +	 * Since touch screen will set trigger register as period trigger. So
>> +	 * when touch screen is enabled, then we have to disable hardware
>> +	 * trigger for classic adc.
>> +	 */
>> +	if (!st->touchscreen_type) {
>> +		ret = at91_adc_buffer_init(idev);
>> +		if (ret < 0) {
>> +			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
>> +			goto error_disable_adc_clk;
>> +		}
>>  
>> -	ret = at91_adc_trigger_init(idev);
>> -	if (ret < 0) {
>> -		dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
>> -		goto error_unregister_buffer;
>> +		ret = at91_adc_trigger_init(idev);
>> +		if (ret < 0) {
>> +			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
>> +			at91_adc_buffer_remove(idev);
>> +			goto error_disable_adc_clk;
>> +		}
>> +	} else {
>> +		if (!st->caps->has_tsmr) {
>> +			dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
>> +			goto error_disable_adc_clk;
>> +		}
>> +
>> +		ret = at91_ts_register(st, pdev);
>> +		if (ret)
>> +			goto error_disable_adc_clk;
>> +
>> +		at91_ts_hw_init(st, adc_clk_khz);
>>  	}
>>  
>>  	ret = iio_device_register(idev);
>>  	if (ret < 0) {
>>  		dev_err(&pdev->dev, "Couldn't register the device.\n");
>> -		goto error_remove_triggers;
>> +		goto error_iio_device_register;
>>  	}
>>  
>>  	return 0;
>>  
>> -error_remove_triggers:
>> -	at91_adc_trigger_remove(idev);
>> -error_unregister_buffer:
>> -	at91_adc_buffer_remove(idev);
>> +error_iio_device_register:
>> +	if (!st->touchscreen_type) {
>> +		at91_adc_trigger_remove(idev);
>> +		at91_adc_buffer_remove(idev);
>> +	} else {
>> +		at91_ts_unregister(st);
>> +	}
>>  error_disable_adc_clk:
>>  	clk_disable_unprepare(st->adc_clk);
>>  error_disable_clk:
>> @@ -762,8 +1093,12 @@ static int at91_adc_remove(struct platform_device *pdev)
>>  	struct at91_adc_state *st = iio_priv(idev);
>>  
>>  	iio_device_unregister(idev);
>> -	at91_adc_trigger_remove(idev);
>> -	at91_adc_buffer_remove(idev);
>> +	if (!st->touchscreen_type) {
>> +		at91_adc_trigger_remove(idev);
>> +		at91_adc_buffer_remove(idev);
>> +	} else {
>> +		at91_ts_unregister(st);
>> +	}
>>  	clk_disable_unprepare(st->adc_clk);
>>  	clk_disable_unprepare(st->clk);
>>  	free_irq(st->irq, idev);
>> @@ -786,6 +1121,7 @@ static struct at91_adc_caps at91sam9260_caps = {
>>  };
>>  
>>  static struct at91_adc_caps at91sam9g45_caps = {
>> +	.has_ts = true,
>>  	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
>>  	.num_channels = 8,
>>  	.registers = {
>> @@ -799,6 +1135,10 @@ static struct at91_adc_caps at91sam9g45_caps = {
>>  };
>>  
>>  static struct at91_adc_caps at91sam9x5_caps = {
>> +	.has_ts = true,
>> +	.has_tsmr = true,
>> +	.ts_filter_average = 3,
>> +	.ts_pen_detect_sensitivity = 2,
>>  	.calc_startup_ticks = calc_startup_ticks_9x5,
>>  	.num_channels = 12,
>>  	.registers = {
>> @@ -825,7 +1165,7 @@ static struct platform_driver at91_adc_driver = {
>>  	.probe = at91_adc_probe,
>>  	.remove = at91_adc_remove,
>>  	.driver = {
>> -		   .name = "at91_adc",
>> +		   .name = DRIVER_NAME,
>>  		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
>>  	},
>>  };
>> -- 
>> 1.7.9.5
>>
>