Re: [PATCH v9 2/9] Input: goodix - reset device at init

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Mon, Oct 12, 2015 at 06:24:30PM +0300, Irina Tirdea wrote:
> After power on, it is recommended that the driver resets the device.
> The reset procedure timing is described in the datasheet and is used
> at device init (before writing device configuration) and
> for power management. It is a sequence of setting the interrupt
> and reset pins high/low at specific timing intervals. This procedure
> also includes setting the slave address to the one specified in the
> ACPI/device tree.
> 
> This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
> driver gt9xx.c for Android (publicly available in Android kernel
> trees for various devices).
> 
> For reset the driver needs to control the interrupt and
> reset gpio pins (configured through ACPI/device tree). For devices
> that do not have the gpio pins properly declared, the functionality
> depending on these pins will not be available, but the device can still
> be used with basic functionality.
> 
> For both device tree and ACPI, the interrupt gpio pin configuration is
> read from the "irq-gpio" property and the reset pin configuration is
> read from the "reset-gpio" property. For ACPI 5.1, named properties
> can be specified using the _DSD section. This functionality will not be
> available for devices that use indexed gpio pins declared in the _CRS
> section (we need to provide backward compatibility with devices
> that do not support using the interrupt gpio pin as output).
> 
> For ACPI, the pins can be specified using ACPI 5.1:
> Device (STAC)
> {
>     Name (_HID, "GDIX1001")
>     ...
> 
>     Method (_CRS, 0, Serialized)
>     {
>         Name (RBUF, ResourceTemplate ()
>         {
>             I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
>                 AddressingMode7Bit, "\\I2C0",
>                 0x00, ResourceConsumer, ,
>                 )
> 
>             GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
>                 "\\I2C0", 0x00, ResourceConsumer, ,
>                  )
>                  {   // Pin list
>                      0
>                  }
> 
>             GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
>                 IoRestrictionOutputOnly, "\\I2C0", 0x00,
>                 ResourceConsumer, ,
>                 )
>                 {
>                      1
>                 }
>         })
>         Return (RBUF)
>     }
> 
>     Name (_DSD,  Package ()
>     {
>         ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>         Package ()
>         {
>             Package (2) {"irq-gpio", Package() {^STAC, 0, 0, 0 }},
>             Package (2) {"reset-gpio", Package() {^STAC, 1, 0, 0 }},
>             ...
>         }
>     }
> 
> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> Acked-by: Bastien Nocera <hadess@hadess.net>
> Tested-by: Bastien Nocera <hadess@hadess.net>
> Tested-by: Aleksei Mamlin <mamlinav@gmail.com>
> ---
>  .../bindings/input/touchscreen/goodix.txt          |   5 +
>  drivers/input/touchscreen/Kconfig                  |   1 +
>  drivers/input/touchscreen/goodix.c                 | 101 +++++++++++++++++++++
>  3 files changed, 107 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> index 8ba98ee..7137881 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> @@ -12,6 +12,8 @@ Required properties:
>   - reg			: I2C address of the chip. Should be 0x5d or 0x14
>   - interrupt-parent	: Interrupt controller to which the chip is connected
>   - interrupts		: Interrupt to which the chip is connected
> + - irq-gpio		: GPIO pin used for IRQ
> + - reset-gpio		: GPIO pin used for reset
>  
>  Example:
>  
> @@ -23,6 +25,9 @@ Example:
>  			reg = <0x5d>;
>  			interrupt-parent = <&gpio>;
>  			interrupts = <0 0>;
> +
> +			irq-gpio = <&gpio1 0 0>;
> +			reset-gpio = <&gpio1 1 0>;
>  		};
>  
>  		/* ... */
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 771d95c..76f5a9d 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -324,6 +324,7 @@ config TOUCHSCREEN_FUJITSU
>  config TOUCHSCREEN_GOODIX
>  	tristate "Goodix I2C touchscreen"
>  	depends on I2C
> +	depends on GPIOLIB
>  	help
>  	  Say Y here if you have the Goodix touchscreen (such as one
>  	  installed in Onda v975w tablets) connected to your
> diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> index 56d0330..87304ac 100644
> --- a/drivers/input/touchscreen/goodix.c
> +++ b/drivers/input/touchscreen/goodix.c
> @@ -16,6 +16,7 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/dmi.h>
> +#include <linux/gpio.h>
>  #include <linux/i2c.h>
>  #include <linux/input.h>
>  #include <linux/input/mt.h>
> @@ -37,8 +38,13 @@ struct goodix_ts_data {
>  	unsigned int int_trigger_type;
>  	bool rotated_screen;
>  	int cfg_len;
> +	struct gpio_desc *gpiod_int;
> +	struct gpio_desc *gpiod_rst;
>  };
>  
> +#define GOODIX_GPIO_INT_NAME		"irq"
> +#define GOODIX_GPIO_RST_NAME		"reset"
> +
>  #define GOODIX_MAX_HEIGHT		4096
>  #define GOODIX_MAX_WIDTH		4096
>  #define GOODIX_INT_TRIGGER		1
> @@ -237,6 +243,88 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static int goodix_int_sync(struct goodix_ts_data *ts)
> +{
> +	int error;
> +
> +	error = gpiod_direction_output(ts->gpiod_int, 0);
> +	if (error)
> +		return error;
> +	msleep(50);				/* T5: 50ms */
> +
> +	return gpiod_direction_input(ts->gpiod_int);
> +}
> +
> +/**
> + * goodix_reset - Reset device during power on
> + *
> + * @ts: goodix_ts_data pointer
> + */
> +static int goodix_reset(struct goodix_ts_data *ts)
> +{
> +	int error;
> +
> +	/* begin select I2C slave addr */
> +	error = gpiod_direction_output(ts->gpiod_rst, 0);
> +	if (error)
> +		return error;
> +	msleep(20);				/* T2: > 10ms */
> +	/* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
> +	error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
> +	if (error)
> +		return error;
> +	usleep_range(100, 2000);		/* T3: > 100us */
> +	error = gpiod_direction_output(ts->gpiod_rst, 1);
> +	if (error)
> +		return error;
> +	usleep_range(6000, 10000);		/* T4: > 5ms */
> +	/* end select I2C slave addr */
> +	error = gpiod_direction_input(ts->gpiod_rst);
> +	if (error)
> +		return error;
> +	return goodix_int_sync(ts);
> +}
> +
> +/**
> + * goodix_get_gpio_config - Get GPIO config from ACPI/DT
> + *
> + * @ts: goodix_ts_data pointer
> + */
> +static int goodix_get_gpio_config(struct goodix_ts_data *ts)
> +{
> +	int error;
> +	struct device *dev;
> +	struct gpio_desc *gpiod;
> +
> +	if (!ts->client)
> +		return -EINVAL;
> +	dev = &ts->client->dev;
> +
> +	/* Get the interrupt GPIO pin number */
> +	gpiod = devm_gpiod_get(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);

Why isn't this devm_gpiod_get_optional()? Then you would not need to
clobber the return value down in goodix_ts_probe().

I can fix it up locally.

Thanks.

-- 
Dmitry