[PATCH v4 1/5] IIO: Ingenic JZ47xx: Add xlate cb to retrieve correct channel idx

[PATCH v4 1/5] IIO: Ingenic JZ47xx: Add xlate cb to retrieve correct channel idx

[Artur Rojek]

Provide an of_xlate callback in order to retrieve the correct channel
specifier index from the IIO channels array.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
---

 Changes:

 v2-v4: no change

 drivers/iio/adc/ingenic-adc.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/iio/adc/ingenic-adc.c b/drivers/iio/adc/ingenic-adc.c
index 39c0a609fc94..7a24bc1dabe1 100644
--- a/drivers/iio/adc/ingenic-adc.c
+++ b/drivers/iio/adc/ingenic-adc.c
@@ -383,6 +383,21 @@ static int ingenic_adc_read_raw(struct iio_dev *iio_dev,
 	}
 }
 
+static int ingenic_adc_of_xlate(struct iio_dev *iio_dev,
+				const struct of_phandle_args *iiospec)
+{
+	int i;
+
+	if (!iiospec->args_count)
+		return -EINVAL;
+
+	for (i = 0; i < iio_dev->num_channels; ++i)
+		if (iio_dev->channels[i].channel == iiospec->args[0])
+			return i;
+
+	return -EINVAL;
+}
+
 static void ingenic_adc_clk_cleanup(void *data)
 {
 	clk_unprepare(data);
@@ -392,6 +407,7 @@ static const struct iio_info ingenic_adc_info = {
 	.write_raw = ingenic_adc_write_raw,
 	.read_raw = ingenic_adc_read_raw,
 	.read_avail = ingenic_adc_read_avail,
+	.of_xlate = ingenic_adc_of_xlate,
 };
 
 static const struct iio_chan_spec ingenic_channels[] = {
-- 
2.25.1

[PATCH v4 2/5] dt-bindings: iio/adc: Add touchscreen idx for JZ47xx SoC ADC

[Artur Rojek]

Introduce support for touchscreen channels found in JZ47xx SoCs.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Rob Herring <robh@kernel.org>
---

 Changes:

 v2-v4: no change

 include/dt-bindings/iio/adc/ingenic,adc.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/dt-bindings/iio/adc/ingenic,adc.h b/include/dt-bindings/iio/adc/ingenic,adc.h
index 42f871ab3272..95e20a8d6dc8 100644
--- a/include/dt-bindings/iio/adc/ingenic,adc.h
+++ b/include/dt-bindings/iio/adc/ingenic,adc.h
@@ -7,5 +7,7 @@
 #define INGENIC_ADC_AUX		0
 #define INGENIC_ADC_BATTERY	1
 #define INGENIC_ADC_AUX2	2
+#define INGENIC_ADC_TOUCH_XP	3
+#define INGENIC_ADC_TOUCH_YP	4
 
 #endif
-- 
2.25.1

[PATCH v4 3/5] IIO: Ingenic JZ47xx: Add touchscreen mode.

[Artur Rojek]

The SADC component in JZ47xx SoCs provides support for touchscreen
operations (pen position and pen down pressure) in single-ended and
differential modes.

Of the known hardware to use this controller, GCW Zero and Anbernic RG-350
utilize the touchscreen mode by having their joystick(s) attached to the
X/Y positive/negative input pins.
GCW Zero comes with a single joystick and is sufficiently handled with the
currently implemented single-ended mode. Support for boards with two
joysticks, where one is hooked up to Xn/Yn and the other to Xp/Yp channels
will need to be provided in the future.

The touchscreen component of SADC takes a significant time to stabilize
after first receiving the clock and a delay of 50ms has been empirically
proven to be a safe value before data sampling can begin.

All the boards which probe this driver have the interrupt provided from
devicetree, with no need to handle a case where the irq was not provided.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
---

 Changes:

 v2: - improve description of the touchscreen mode,
     - get rid of the unneeded kfifo,
     - drop IIO_BUFFER_CB from Kconfig,
     - remove extended names from the touchscreen channels

 v3: remove unneeded `linux/iio/kfifo_buf.h` include

 v4: clarify irq provider source in the patch description

 drivers/iio/adc/Kconfig       |   1 +
 drivers/iio/adc/ingenic-adc.c | 109 +++++++++++++++++++++++++++++++++-
 2 files changed, 108 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 82e33082958c..d3fd4b6e2d47 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -453,6 +453,7 @@ config INA2XX_ADC
 config INGENIC_ADC
 	tristate "Ingenic JZ47xx SoCs ADC driver"
 	depends on MIPS || COMPILE_TEST
+	select IIO_BUFFER
 	help
 	  Say yes here to build support for the Ingenic JZ47xx SoCs ADC unit.
 
diff --git a/drivers/iio/adc/ingenic-adc.c b/drivers/iio/adc/ingenic-adc.c
index 7a24bc1dabe1..0dafc8d5d0d8 100644
--- a/drivers/iio/adc/ingenic-adc.c
+++ b/drivers/iio/adc/ingenic-adc.c
@@ -8,7 +8,9 @@
 
 #include <dt-bindings/iio/adc/ingenic,adc.h>
 #include <linux/clk.h>
+#include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
@@ -20,6 +22,8 @@
 #define JZ_ADC_REG_CFG			0x04
 #define JZ_ADC_REG_CTRL			0x08
 #define JZ_ADC_REG_STATUS		0x0c
+#define JZ_ADC_REG_ADSAME		0x10
+#define JZ_ADC_REG_ADWAIT		0x14
 #define JZ_ADC_REG_ADTCH		0x18
 #define JZ_ADC_REG_ADBDAT		0x1c
 #define JZ_ADC_REG_ADSDAT		0x20
@@ -28,6 +32,9 @@
 #define JZ_ADC_REG_ENABLE_PD		BIT(7)
 #define JZ_ADC_REG_CFG_AUX_MD		(BIT(0) | BIT(1))
 #define JZ_ADC_REG_CFG_BAT_MD		BIT(4)
+#define JZ_ADC_REG_CFG_PULL_UP(n)	((n) << 16)
+#define JZ_ADC_REG_CFG_SAMPLE_NUM(n)	((n) << 10)
+#define JZ_ADC_REG_CFG_TOUCH_OPS_MASK	(BIT(31) | GENMASK(23, 10))
 #define JZ_ADC_REG_ADCLK_CLKDIV_LSB	0
 #define JZ4725B_ADC_REG_ADCLK_CLKDIV10US_LSB	16
 #define JZ4770_ADC_REG_ADCLK_CLKDIV10US_LSB	8
@@ -44,6 +51,14 @@
 #define JZ4770_ADC_BATTERY_VREF			6600
 #define JZ4770_ADC_BATTERY_VREF_BITS		12
 
+#define JZ_ADC_IRQ_AUX			BIT(0)
+#define JZ_ADC_IRQ_BATTERY		BIT(1)
+#define JZ_ADC_IRQ_TOUCH		BIT(2)
+#define JZ_ADC_IRQ_PEN_DOWN		BIT(3)
+#define JZ_ADC_IRQ_PEN_UP		BIT(4)
+#define JZ_ADC_IRQ_PEN_DOWN_SLEEP	BIT(5)
+#define JZ_ADC_IRQ_SLEEP		BIT(7)
+
 struct ingenic_adc;
 
 struct ingenic_adc_soc_data {
@@ -411,6 +426,28 @@ static const struct iio_info ingenic_adc_info = {
 };
 
 static const struct iio_chan_spec ingenic_channels[] = {
+	{
+		.type = IIO_POSITIONRELATIVE,
+		.indexed = 1,
+		.channel = INGENIC_ADC_TOUCH_XP,
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 12,
+			.storagebits = 16
+		},
+	},
+	{
+		.type = IIO_POSITIONRELATIVE,
+		.indexed = 1,
+		.channel = INGENIC_ADC_TOUCH_YP,
+		.scan_index = 1,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 12,
+			.storagebits = 16
+		},
+	},
 	{
 		.extend_name = "aux",
 		.type = IIO_VOLTAGE,
@@ -418,6 +455,7 @@ static const struct iio_chan_spec ingenic_channels[] = {
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.indexed = 1,
 		.channel = INGENIC_ADC_AUX,
+		.scan_index = -1
 	},
 	{
 		.extend_name = "battery",
@@ -428,6 +466,7 @@ static const struct iio_chan_spec ingenic_channels[] = {
 						BIT(IIO_CHAN_INFO_SCALE),
 		.indexed = 1,
 		.channel = INGENIC_ADC_BATTERY,
+		.scan_index = -1
 	},
 	{ /* Must always be last in the array. */
 		.extend_name = "aux2",
@@ -436,16 +475,69 @@ static const struct iio_chan_spec ingenic_channels[] = {
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.indexed = 1,
 		.channel = INGENIC_ADC_AUX2,
+		.scan_index = -1
 	},
 };
 
+static int ingenic_adc_buffer_enable(struct iio_dev *iio_dev)
+{
+	struct ingenic_adc *adc = iio_priv(iio_dev);
+
+	clk_enable(adc->clk);
+	/* It takes significant time for the touchscreen hw to stabilize. */
+	msleep(50);
+	ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_TOUCH_OPS_MASK,
+			       JZ_ADC_REG_CFG_SAMPLE_NUM(4) |
+			       JZ_ADC_REG_CFG_PULL_UP(4));
+	writew(80, adc->base + JZ_ADC_REG_ADWAIT);
+	writew(2, adc->base + JZ_ADC_REG_ADSAME);
+	writeb((u8)~JZ_ADC_IRQ_TOUCH, adc->base + JZ_ADC_REG_CTRL);
+	writel(0, adc->base + JZ_ADC_REG_ADTCH);
+	ingenic_adc_enable(adc, 2, true);
+
+	return 0;
+}
+
+static int ingenic_adc_buffer_disable(struct iio_dev *iio_dev)
+{
+	struct ingenic_adc *adc = iio_priv(iio_dev);
+
+	ingenic_adc_enable(adc, 2, false);
+	writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
+	writeb(0xff, adc->base + JZ_ADC_REG_STATUS);
+	ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_TOUCH_OPS_MASK, 0);
+	writew(0, adc->base + JZ_ADC_REG_ADSAME);
+	writew(0, adc->base + JZ_ADC_REG_ADWAIT);
+	clk_disable(adc->clk);
+
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops ingenic_buffer_setup_ops = {
+	.postenable = &ingenic_adc_buffer_enable,
+	.predisable = &ingenic_adc_buffer_disable
+};
+
+static irqreturn_t ingenic_adc_irq(int irq, void *data)
+{
+	struct iio_dev *iio_dev = data;
+	struct ingenic_adc *adc = iio_priv(iio_dev);
+	u32 tdat;
+
+	tdat = readl(adc->base + JZ_ADC_REG_ADTCH);
+	iio_push_to_buffers(iio_dev, &tdat);
+	writeb(JZ_ADC_IRQ_TOUCH, adc->base + JZ_ADC_REG_STATUS);
+
+	return IRQ_HANDLED;
+}
+
 static int ingenic_adc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct iio_dev *iio_dev;
 	struct ingenic_adc *adc;
 	const struct ingenic_adc_soc_data *soc_data;
-	int ret;
+	int irq, ret;
 
 	soc_data = device_get_match_data(dev);
 	if (!soc_data)
@@ -460,6 +552,18 @@ static int ingenic_adc_probe(struct platform_device *pdev)
 	mutex_init(&adc->aux_lock);
 	adc->soc_data = soc_data;
 
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "Failed to get irq: %d\n", irq);
+		return irq;
+	}
+	ret = devm_request_irq(dev, irq, ingenic_adc_irq, 0,
+			       dev_name(dev), iio_dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to request irq: %d\n", ret);
+		return ret;
+	}
+
 	adc->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(adc->base))
 		return PTR_ERR(adc->base);
@@ -499,7 +603,8 @@ static int ingenic_adc_probe(struct platform_device *pdev)
 
 	iio_dev->dev.parent = dev;
 	iio_dev->name = "jz-adc";
-	iio_dev->modes = INDIO_DIRECT_MODE;
+	iio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
+	iio_dev->setup_ops = &ingenic_buffer_setup_ops;
 	iio_dev->channels = ingenic_channels;
 	iio_dev->num_channels = ARRAY_SIZE(ingenic_channels);
 	/* Remove AUX2 from the list of supported channels. */
-- 
2.25.1

[PATCH v4 4/5] dt-bindings: input: Add docs for ADC driven joystick.

[Artur Rojek]

Add documentation for the adc-joystick driver, used to provide support
for joysticks connected over ADC.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
---

 Changes:

 v2: - Add `reg` property to axis subnode in order to enumerate the axes,
     - rename `linux,abs-code` property to `linux,code`,
     - drop `linux,` prefix from the remaining properties of axis subnode

 v3: no change

 v4: - remove "bindings" from the unique identifier string,
     - replace `|` with `>` for all description properties,
     - specify the number of items for `io-channels`,
     - correct the regex pattern of `axis` property,
     - specify the value range of `reg` property for each axis,
     - put `abs-range` properties under `allOf` 

 .../bindings/input/adc-joystick.yaml          | 121 ++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/adc-joystick.yaml

diff --git a/Documentation/devicetree/bindings/input/adc-joystick.yaml b/Documentation/devicetree/bindings/input/adc-joystick.yaml
new file mode 100644
index 000000000000..b0d2aa28d8c6
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/adc-joystick.yaml
@@ -0,0 +1,121 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2019-2020 Artur Rojek
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/input/adc-joystick.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: ADC attached joystick
+
+maintainers:
+  - Artur Rojek <contact@artur-rojek.eu>
+
+description: >
+  Bindings for joystick devices connected to ADC controllers supporting
+  the Industrial I/O subsystem.
+
+properties:
+  compatible:
+    const: adc-joystick
+
+  io-channels:
+    minItems: 1
+    maxItems: 1024
+    description: >
+      List of phandle and IIO specifier pairs.
+      Each pair defines one ADC channel to which a joystick axis is connected.
+      See Documentation/devicetree/bindings/iio/iio-bindings.txt for details.
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+required:
+  - compatible
+  - io-channels
+  - '#address-cells'
+  - '#size-cells'
+
+additionalProperties: false
+
+patternProperties:
+  "^axis@[0-9]+$":
+    type: object
+    description: >
+      Represents a joystick axis bound to the given ADC channel.
+      For each entry in the io-channels list, one axis subnode with a matching
+      reg property must be specified.
+
+    properties:
+      reg:
+        minimum: 0
+        maximum: 1023
+        description: Index of an io-channels list entry bound to this axis.
+
+      linux,code:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: EV_ABS specific event code generated by the axis.
+
+      abs-range:
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32-array
+          - items:
+              - description: minimum value
+              - description: maximum value
+        description: >
+          Minimum and maximum values produced by the axis.
+          For an ABS_X axis this will be the left-most and right-most
+          inclination of the joystick. If min > max, it is left to userspace to
+          treat the axis as inverted.
+          This property is interpreted as two signed 32 bit values.
+
+      abs-fuzz:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: >
+          Amount of noise in the input value.
+          Omitting this property indicates the axis is precise.
+
+      abs-flat:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: >
+          Axial "deadzone", or area around the center position, where the axis
+          is considered to be at rest.
+          Omitting this property indicates the axis always returns to exactly
+          the center position.
+
+    required:
+      - reg
+      - linux,code
+      - abs-range
+
+    additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/iio/adc/ingenic,adc.h>
+    #include <dt-bindings/input/input.h>
+
+    joystick: adc-joystick {
+      compatible = "adc-joystick";
+      io-channels = <&adc INGENIC_ADC_TOUCH_XP>,
+                    <&adc INGENIC_ADC_TOUCH_YP>;
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      axis@0 {
+              reg = <0>;
+              linux,code = <ABS_X>;
+              abs-range = <3300 0>;
+              abs-fuzz = <4>;
+              abs-flat = <200>;
+      };
+      axis@1 {
+              reg = <1>;
+              linux,code = <ABS_Y>;
+              abs-range = <0 3300>;
+              abs-fuzz = <4>;
+              abs-flat = <200>;
+      };
+    };
-- 
2.25.1

Re: [PATCH v4 4/5] dt-bindings: input: Add docs for ADC driven joystick.

[Rob Herring]

On Sat,  7 Mar 2020 22:14:11 +0100, Artur Rojek wrote:
> Add documentation for the adc-joystick driver, used to provide support
> for joysticks connected over ADC.
> 
> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
> Tested-by: Paul Cercueil <paul@crapouillou.net>
> ---
> 
>  Changes:
> 
>  v2: - Add `reg` property to axis subnode in order to enumerate the axes,
>      - rename `linux,abs-code` property to `linux,code`,
>      - drop `linux,` prefix from the remaining properties of axis subnode
> 
>  v3: no change
> 
>  v4: - remove "bindings" from the unique identifier string,
>      - replace `|` with `>` for all description properties,
>      - specify the number of items for `io-channels`,
>      - correct the regex pattern of `axis` property,
>      - specify the value range of `reg` property for each axis,
>      - put `abs-range` properties under `allOf` 
> 
>  .../bindings/input/adc-joystick.yaml          | 121 ++++++++++++++++++
>  1 file changed, 121 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/adc-joystick.yaml
> 

My bot found errors running 'make dt_binding_check' on your patch:

Error: Documentation/devicetree/bindings/input/adc-joystick.example.dts:22.31-32 syntax error
FATAL ERROR: Unable to parse input tree
scripts/Makefile.lib:311: recipe for target 'Documentation/devicetree/bindings/input/adc-joystick.example.dt.yaml' failed
make[1]: *** [Documentation/devicetree/bindings/input/adc-joystick.example.dt.yaml] Error 1
Makefile:1262: recipe for target 'dt_binding_check' failed
make: *** [dt_binding_check] Error 2

See https://patchwork.ozlabs.org/patch/1250951
Please check and re-submit.

Re: [PATCH v4 4/5] dt-bindings: input: Add docs for ADC driven joystick.

[Artur Rojek]

Hi Rob,

On 2020-03-09 21:38, Rob Herring wrote:
> On Sat,  7 Mar 2020 22:14:11 +0100, Artur Rojek wrote:
>> Add documentation for the adc-joystick driver, used to provide support
>> for joysticks connected over ADC.
>> 
>> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
>> Tested-by: Paul Cercueil <paul@crapouillou.net>
>> ---
>> 
>>  Changes:
>> 
>>  v2: - Add `reg` property to axis subnode in order to enumerate the 
>> axes,
>>      - rename `linux,abs-code` property to `linux,code`,
>>      - drop `linux,` prefix from the remaining properties of axis 
>> subnode
>> 
>>  v3: no change
>> 
>>  v4: - remove "bindings" from the unique identifier string,
>>      - replace `|` with `>` for all description properties,
>>      - specify the number of items for `io-channels`,
>>      - correct the regex pattern of `axis` property,
>>      - specify the value range of `reg` property for each axis,
>>      - put `abs-range` properties under `allOf`
>> 
>>  .../bindings/input/adc-joystick.yaml          | 121 
>> ++++++++++++++++++
>>  1 file changed, 121 insertions(+)
>>  create mode 100644 
>> Documentation/devicetree/bindings/input/adc-joystick.yaml
>> 
> 
> My bot found errors running 'make dt_binding_check' on your patch:
Like with the previous versions of this patch set, the DTS example 
requires that
patch [2/5] is applied first. When that is done, the DT check does 
succeed here.

Regards,
Artur
> 
> Error:
> Documentation/devicetree/bindings/input/adc-joystick.example.dts:22.31-32
> syntax error
> FATAL ERROR: Unable to parse input tree
> scripts/Makefile.lib:311: recipe for target
> 'Documentation/devicetree/bindings/input/adc-joystick.example.dt.yaml'
> failed
> make[1]: ***
> [Documentation/devicetree/bindings/input/adc-joystick.example.dt.yaml]
> Error 1
> Makefile:1262: recipe for target 'dt_binding_check' failed
> make: *** [dt_binding_check] Error 2
> 
> See https://patchwork.ozlabs.org/patch/1250951
> Please check and re-submit.

Re: [PATCH v4 4/5] dt-bindings: input: Add docs for ADC driven joystick.

[Jonathan Cameron]

On Mon, 09 Mar 2020 22:41:00 +0100
Artur Rojek <contact@artur-rojek.eu> wrote:

> Hi Rob,
> 
> On 2020-03-09 21:38, Rob Herring wrote:
> > On Sat,  7 Mar 2020 22:14:11 +0100, Artur Rojek wrote:  
> >> Add documentation for the adc-joystick driver, used to provide support
> >> for joysticks connected over ADC.
> >> 
> >> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
> >> Tested-by: Paul Cercueil <paul@crapouillou.net>
> >> ---
> >> 
> >>  Changes:
> >> 
> >>  v2: - Add `reg` property to axis subnode in order to enumerate the 
> >> axes,
> >>      - rename `linux,abs-code` property to `linux,code`,
> >>      - drop `linux,` prefix from the remaining properties of axis 
> >> subnode
> >> 
> >>  v3: no change
> >> 
> >>  v4: - remove "bindings" from the unique identifier string,
> >>      - replace `|` with `>` for all description properties,
> >>      - specify the number of items for `io-channels`,
> >>      - correct the regex pattern of `axis` property,
> >>      - specify the value range of `reg` property for each axis,
> >>      - put `abs-range` properties under `allOf`
> >> 
> >>  .../bindings/input/adc-joystick.yaml          | 121 
> >> ++++++++++++++++++
> >>  1 file changed, 121 insertions(+)
> >>  create mode 100644 
> >> Documentation/devicetree/bindings/input/adc-joystick.yaml
> >>   
> > 
> > My bot found errors running 'make dt_binding_check' on your patch:  
> Like with the previous versions of this patch set, the DTS example 
> requires that
> patch [2/5] is applied first. When that is done, the DT check does 
> succeed here.

Fair enough as far as I am concerned.   There were enough comments
from Rob in the previous version though that I'd definitely like
him to take another look before I pick this series up.

Thanks,

Jonathan

> 
> Regards,
> Artur
> > 
> > Error:
> > Documentation/devicetree/bindings/input/adc-joystick.example.dts:22.31-32
> > syntax error
> > FATAL ERROR: Unable to parse input tree
> > scripts/Makefile.lib:311: recipe for target
> > 'Documentation/devicetree/bindings/input/adc-joystick.example.dt.yaml'
> > failed
> > make[1]: ***
> > [Documentation/devicetree/bindings/input/adc-joystick.example.dt.yaml]
> > Error 1
> > Makefile:1262: recipe for target 'dt_binding_check' failed
> > make: *** [dt_binding_check] Error 2
> > 
> > See https://patchwork.ozlabs.org/patch/1250951
> > Please check and re-submit.  

Re: [PATCH v4 4/5] dt-bindings: input: Add docs for ADC driven joystick.

[Rob Herring]

On Sat, Mar 7, 2020 at 2:06 PM Artur Rojek <contact@artur-rojek.eu> wrote:
>
> Add documentation for the adc-joystick driver, used to provide support
> for joysticks connected over ADC.
>
> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
> Tested-by: Paul Cercueil <paul@crapouillou.net>
> ---
>
>  Changes:
>
>  v2: - Add `reg` property to axis subnode in order to enumerate the axes,
>      - rename `linux,abs-code` property to `linux,code`,
>      - drop `linux,` prefix from the remaining properties of axis subnode
>
>  v3: no change
>
>  v4: - remove "bindings" from the unique identifier string,
>      - replace `|` with `>` for all description properties,
>      - specify the number of items for `io-channels`,
>      - correct the regex pattern of `axis` property,
>      - specify the value range of `reg` property for each axis,
>      - put `abs-range` properties under `allOf`
>
>  .../bindings/input/adc-joystick.yaml          | 121 ++++++++++++++++++
>  1 file changed, 121 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/adc-joystick.yaml
>
> diff --git a/Documentation/devicetree/bindings/input/adc-joystick.yaml b/Documentation/devicetree/bindings/input/adc-joystick.yaml
> new file mode 100644
> index 000000000000..b0d2aa28d8c6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/adc-joystick.yaml
> @@ -0,0 +1,121 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2019-2020 Artur Rojek
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/input/adc-joystick.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: ADC attached joystick
> +
> +maintainers:
> +  - Artur Rojek <contact@artur-rojek.eu>
> +
> +description: >
> +  Bindings for joystick devices connected to ADC controllers supporting
> +  the Industrial I/O subsystem.
> +
> +properties:
> +  compatible:
> +    const: adc-joystick
> +
> +  io-channels:
> +    minItems: 1
> +    maxItems: 1024
> +    description: >
> +      List of phandle and IIO specifier pairs.
> +      Each pair defines one ADC channel to which a joystick axis is connected.
> +      See Documentation/devicetree/bindings/iio/iio-bindings.txt for details.
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +required:
> +  - compatible
> +  - io-channels
> +  - '#address-cells'
> +  - '#size-cells'
> +
> +additionalProperties: false
> +
> +patternProperties:
> +  "^axis@[0-9]+$":

unit-addresses are hex, so add 'a-f' in there.

With that,

Reviewed-by: Rob Herring <robh@kernel.org>

[PATCH v4 5/5] input: joystick: Add ADC attached joystick driver.

[Artur Rojek]

Add a driver for joystick devices connected to ADC controllers
supporting the Industrial I/O subsystem.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---

 v2: - sanity check supported channel format on probe,
     - rename adc_joystick_disable to a more sensible adc_joystick_cleanup, 
     - enforce correct axis order by checking the `reg` property of
       child nodes

 v3-v4: no change

 drivers/input/joystick/Kconfig        |  10 ++
 drivers/input/joystick/Makefile       |   1 +
 drivers/input/joystick/adc-joystick.c | 245 ++++++++++++++++++++++++++
 3 files changed, 256 insertions(+)
 create mode 100644 drivers/input/joystick/adc-joystick.c

diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
index 940b744639c7..efbc20ec5099 100644
--- a/drivers/input/joystick/Kconfig
+++ b/drivers/input/joystick/Kconfig
@@ -42,6 +42,16 @@ config JOYSTICK_A3D
 	  To compile this driver as a module, choose M here: the
 	  module will be called a3d.
 
+config JOYSTICK_ADC
+	tristate "Simple joystick connected over ADC"
+	depends on IIO
+	select IIO_BUFFER_CB
+	help
+	  Say Y here if you have a simple joystick connected over ADC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called adc-joystick.
+
 config JOYSTICK_ADI
 	tristate "Logitech ADI digital joysticks and gamepads"
 	select GAMEPORT
diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
index 8656023f6ef5..58232b3057d3 100644
--- a/drivers/input/joystick/Makefile
+++ b/drivers/input/joystick/Makefile
@@ -6,6 +6,7 @@
 # Each configuration option enables a list of files.
 
 obj-$(CONFIG_JOYSTICK_A3D)		+= a3d.o
+obj-$(CONFIG_JOYSTICK_ADC)		+= adc-joystick.o
 obj-$(CONFIG_JOYSTICK_ADI)		+= adi.o
 obj-$(CONFIG_JOYSTICK_AMIGA)		+= amijoy.o
 obj-$(CONFIG_JOYSTICK_AS5011)		+= as5011.o
diff --git a/drivers/input/joystick/adc-joystick.c b/drivers/input/joystick/adc-joystick.c
new file mode 100644
index 000000000000..9cb9896da26e
--- /dev/null
+++ b/drivers/input/joystick/adc-joystick.c
@@ -0,0 +1,245 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Input driver for joysticks connected over ADC.
+ * Copyright (c) 2019-2020 Artur Rojek <contact@artur-rojek.eu>
+ */
+#include <linux/ctype.h>
+#include <linux/input.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+struct adc_joystick_axis {
+	u32 code;
+	s32 range[2];
+	s32 fuzz;
+	s32 flat;
+};
+
+struct adc_joystick {
+	struct input_dev *input;
+	struct iio_cb_buffer *buffer;
+	struct adc_joystick_axis *axes;
+	struct iio_channel *chans;
+	int num_chans;
+};
+
+static int adc_joystick_handle(const void *data, void *private)
+{
+	struct adc_joystick *joy = private;
+	enum iio_endian endianness;
+	int bytes, msb, val, i;
+	bool sign;
+
+	bytes = joy->chans[0].channel->scan_type.storagebits >> 3;
+
+	for (i = 0; i < joy->num_chans; ++i) {
+		endianness = joy->chans[i].channel->scan_type.endianness;
+		msb = joy->chans[i].channel->scan_type.realbits - 1;
+		sign = (tolower(joy->chans[i].channel->scan_type.sign) == 's');
+
+		switch (bytes) {
+		case 1:
+			val = ((const u8 *)data)[i];
+			break;
+		case 2:
+			val = ((const u16 *)data)[i];
+			if (endianness == IIO_BE)
+				val = be16_to_cpu(val);
+			else if (endianness == IIO_LE)
+				val = le16_to_cpu(val);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		val >>= joy->chans[i].channel->scan_type.shift;
+		if (sign)
+			val = sign_extend32(val, msb);
+		else
+			val &= GENMASK(msb, 0);
+		input_report_abs(joy->input, joy->axes[i].code, val);
+	}
+
+	input_sync(joy->input);
+
+	return 0;
+}
+
+static int adc_joystick_open(struct input_dev *dev)
+{
+	struct adc_joystick *joy = input_get_drvdata(dev);
+	int ret;
+
+	ret = iio_channel_start_all_cb(joy->buffer);
+	if (ret)
+		dev_err(dev->dev.parent, "Unable to start callback buffer");
+
+	return ret;
+}
+
+static void adc_joystick_close(struct input_dev *dev)
+{
+	struct adc_joystick *joy = input_get_drvdata(dev);
+
+	iio_channel_stop_all_cb(joy->buffer);
+}
+
+static void adc_joystick_cleanup(void *data)
+{
+	iio_channel_release_all_cb(data);
+}
+
+static int adc_joystick_set_axes(struct device *dev, struct adc_joystick *joy)
+{
+	struct adc_joystick_axis *axes;
+	struct fwnode_handle *child;
+	int num_axes, ret, i;
+
+	num_axes = device_get_child_node_count(dev);
+	if (!num_axes) {
+		dev_err(dev, "Unable to find child nodes");
+		return -EINVAL;
+	}
+
+	if (num_axes != joy->num_chans) {
+		dev_err(dev, "Got %d child nodes for %d channels",
+			num_axes, joy->num_chans);
+		return -EINVAL;
+	}
+
+	axes = devm_kmalloc_array(dev, num_axes, sizeof(*axes), GFP_KERNEL);
+	if (!axes)
+		return -ENOMEM;
+
+	device_for_each_child_node(dev, child) {
+		ret = fwnode_property_read_u32(child, "reg", &i);
+		if (ret || i >= num_axes) {
+			dev_err(dev, "reg invalid or missing");
+			goto err;
+		}
+
+		if (fwnode_property_read_u32(child, "linux,code",
+					     &axes[i].code)) {
+			dev_err(dev, "linux,code invalid or missing");
+			goto err;
+		}
+
+		if (fwnode_property_read_u32_array(child, "abs-range",
+						   axes[i].range, 2)) {
+			dev_err(dev, "abs-range invalid or missing");
+			goto err;
+		}
+
+		fwnode_property_read_u32(child, "abs-fuzz",
+					 &axes[i].fuzz);
+		fwnode_property_read_u32(child, "abs-flat",
+					 &axes[i].flat);
+
+		input_set_abs_params(joy->input, axes[i].code,
+				     axes[i].range[0], axes[i].range[1],
+				     axes[i].fuzz,
+				     axes[i].flat);
+		input_set_capability(joy->input, EV_ABS, axes[i].code);
+	}
+
+	joy->axes = axes;
+
+	return 0;
+
+err:
+	fwnode_handle_put(child);
+	return -EINVAL;
+}
+
+static int adc_joystick_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct adc_joystick *joy;
+	struct input_dev *input;
+	int bits, ret, i;
+
+	joy = devm_kzalloc(dev, sizeof(*joy), GFP_KERNEL);
+	if (!joy)
+		return -ENOMEM;
+
+	joy->chans = devm_iio_channel_get_all(dev);
+	if (IS_ERR(joy->chans)) {
+		ret = PTR_ERR(joy->chans);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Unable to get IIO channels");
+		return ret;
+	}
+
+	/* Count how many channels we got. NULL terminated. */
+	while (joy->chans[joy->num_chans].indio_dev)
+		joy->num_chans++;
+
+	bits = joy->chans[0].channel->scan_type.storagebits;
+	if (!bits || (bits >> 3) > 2) {
+		dev_err(dev, "Unsupported channel storage size");
+		return -EINVAL;
+	}
+	for (i = 1; i < joy->num_chans; ++i)
+		if (joy->chans[i].channel->scan_type.storagebits != bits) {
+			dev_err(dev, "Channels must have equal storage size");
+			return -EINVAL;
+		}
+
+	input = devm_input_allocate_device(dev);
+	if (!input) {
+		dev_err(dev, "Unable to allocate input device");
+		return -ENOMEM;
+	}
+
+	joy->input = input;
+	input->name = pdev->name;
+	input->id.bustype = BUS_HOST;
+	input->open = adc_joystick_open;
+	input->close = adc_joystick_close;
+
+	ret = adc_joystick_set_axes(dev, joy);
+	if (ret)
+		return ret;
+
+	input_set_drvdata(input, joy);
+	ret = input_register_device(input);
+	if (ret) {
+		dev_err(dev, "Unable to register input device: %d", ret);
+		return ret;
+	}
+
+	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);
+	if (IS_ERR(joy->buffer)) {
+		dev_err(dev, "Unable to allocate callback buffer");
+		return PTR_ERR(joy->buffer);
+	}
+
+	ret = devm_add_action_or_reset(dev, adc_joystick_cleanup, joy->buffer);
+	if (ret)
+		dev_err(dev, "Unable to add action");
+
+	return ret;
+}
+
+static const struct of_device_id adc_joystick_of_match[] = {
+	{ .compatible = "adc-joystick", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, adc_joystick_of_match);
+
+static struct platform_driver adc_joystick_driver = {
+	.driver = {
+		.name = "adc-joystick",
+		.of_match_table = of_match_ptr(adc_joystick_of_match),
+	},
+	.probe = adc_joystick_probe,
+};
+module_platform_driver(adc_joystick_driver);
+
+MODULE_DESCRIPTION("Input driver for joysticks connected over ADC");
+MODULE_AUTHOR("Artur Rojek <contact@artur-rojek.eu>");
+MODULE_LICENSE("GPL");
-- 
2.25.1