[PATCH v4 0/3] novatek-nvt-ts: add support for NT36672A touchscreen

[PATCH v4 0/3] novatek-nvt-ts: add support for NT36672A touchscreen

[Joel Selvaraj via B4 Relay]

Extend the novatek touchscreen driver to support NT36672A chip which
is found in phones like qcom/sdm845-xiaomi-beryllium-tianma.dts.
Added devicetree support for the driver and used i2c chip data to handle
the variation in chip id and wake type. Also added vcc and iovcc
regulators which are used to power the touchscreen hardware.

Signed-off-by: Joel Selvaraj <joelselvaraj.oss@gmail.com>
---
Changes in v4:
- Use lowercase i2c device id as suggested by Hans de Goede.
- Disable the regulators after nvt_ts_read_data during probe.
- Link to v3: https://lore.kernel.org/r/20240526-nvt-ts-devicetree-regulator-support-v3-0-aa88d10ccd9a@gmail.com

Changes in v3:
- Fix indentation in the binding as suggested by Krzysztof Kozlowski.
- Picked up Krzysztof Kozlowski's Reviewed-by tag for the binding.
- Link to v2: https://lore.kernel.org/r/20240524-nvt-ts-devicetree-regulator-support-v2-0-b74947038c44@gmail.com

Changes in v2:
- The generic i2c device id is now replaced with the correct IC variant
  provided by Hans de Goede
- Updated the bindings to reflect the latest changes and also incorporated
  the suggestions provided by Krzysztof Kozlowski
- Link to v1: https://lore.kernel.org/r/20240521-nvt-ts-devicetree-regulator-support-v1-0-8d766c639dca@gmail.com

---
Joel Selvaraj (3):
      Input: novatek-nvt-ts: replace generic i2c device id with specific IC variant
      dt-bindings: input: document Novatek NVT touchscreen controller
      Input: novatek-nvt-ts: add support for NT36672A touchscreen

 .../bindings/input/touchscreen/novatek,nvt-ts.yaml | 62 +++++++++++++++++++
 MAINTAINERS                                        |  1 +
 drivers/input/touchscreen/novatek-nvt-ts.c         | 70 ++++++++++++++++++++--
 drivers/platform/x86/x86-android-tablets/other.c   |  2 +-
 4 files changed, 128 insertions(+), 7 deletions(-)
---
base-commit: 6578aac6a270bd6deb9f9319b991dd430de263dd
change-id: 20240518-nvt-ts-devicetree-regulator-support-ac9e49b78a16

Best regards,
-- 
Joel Selvaraj <joelselvaraj.oss@gmail.com>

[PATCH v4 1/3] Input: novatek-nvt-ts: replace generic i2c device id with specific IC variant

[Joel Selvaraj via B4 Relay]

From: Joel Selvaraj <joelselvaraj.oss@gmail.com>

This is done in preparation to introduce other variants of the Novatek NVT
touchscreen controller that can be supported by the driver.

Signed-off-by: Joel Selvaraj <joelselvaraj.oss@gmail.com>
---
 drivers/input/touchscreen/novatek-nvt-ts.c       | 2 +-
 drivers/platform/x86/x86-android-tablets/other.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/novatek-nvt-ts.c b/drivers/input/touchscreen/novatek-nvt-ts.c
index 1a797e410a3fa..9bee3a0c122fb 100644
--- a/drivers/input/touchscreen/novatek-nvt-ts.c
+++ b/drivers/input/touchscreen/novatek-nvt-ts.c
@@ -278,7 +278,7 @@ static int nvt_ts_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id nvt_ts_i2c_id[] = {
-	{ "NVT-ts" },
+	{ "nt11205-ts" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
diff --git a/drivers/platform/x86/x86-android-tablets/other.c b/drivers/platform/x86/x86-android-tablets/other.c
index eb0e55c69dfed..129273df0fdeb 100644
--- a/drivers/platform/x86/x86-android-tablets/other.c
+++ b/drivers/platform/x86/x86-android-tablets/other.c
@@ -40,7 +40,7 @@ static const struct x86_i2c_client_info acer_b1_750_i2c_clients[] __initconst =
 	{
 		/* Novatek NVT-ts touchscreen */
 		.board_info = {
-			.type = "NVT-ts",
+			.type = "nt11205-ts",
 			.addr = 0x34,
 			.dev_name = "NVT-ts",
 		},

-- 
2.45.1

[PATCH v4 2/3] dt-bindings: input: document Novatek NVT touchscreen controller

[Joel Selvaraj via B4 Relay]

From: Joel Selvaraj <joelselvaraj.oss@gmail.com>

Document the Novatek NVT touchscreen controller present in devices like
qcom/sdm845-xiaomi-beryllium-tianma.dts. Also, include the devictree
binding file in the MAINTAINERS file.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Joel Selvaraj <joelselvaraj.oss@gmail.com>
---
 .../bindings/input/touchscreen/novatek,nvt-ts.yaml | 62 ++++++++++++++++++++++
 MAINTAINERS                                        |  1 +
 2 files changed, 63 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/novatek,nvt-ts.yaml b/Documentation/devicetree/bindings/input/touchscreen/novatek,nvt-ts.yaml
new file mode 100644
index 0000000000000..bd6a60486d1f1
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/novatek,nvt-ts.yaml
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/novatek,nvt-ts.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Novatek NVT Touchscreen Controller
+
+maintainers:
+  - Hans de Goede <hdegoede@redhat.com>
+
+allOf:
+  - $ref: touchscreen.yaml#
+
+properties:
+  compatible:
+    enum:
+      - novatek,nt11205-ts
+      - novatek,nt36672a-ts
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  reset-gpios:
+    maxItems: 1
+
+  vcc-supply: true
+  iovcc-supply: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        touchscreen@1 {
+            compatible = "novatek,nt36672a-ts";
+            reg = <0x01>;
+            interrupts-extended = <&tlmm 31 IRQ_TYPE_EDGE_RISING>;
+            reset-gpios = <&tlmm 32 GPIO_ACTIVE_LOW>;
+            vcc-supply = <&vreg_l22a_2p85>;
+            iovcc-supply = <&vreg_l14a_1p8>;
+            pinctrl-0 = <&ts_int_default &ts_reset_default>;
+            pinctrl-1 = <&ts_int_sleep &ts_reset_sleep>;
+            pinctrl-names = "default", "sleep";
+            touchscreen-size-x = <1080>;
+            touchscreen-size-y = <2246>;
+        };
+    };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 90754a451bcfc..e1f744992b15f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15942,6 +15942,7 @@ NOVATEK NVT-TS I2C TOUCHSCREEN DRIVER
 M:	Hans de Goede <hdegoede@redhat.com>
 L:	linux-input@vger.kernel.org
 S:	Maintained
+F:	Documentation/devicetree/bindings/input/touchscreen/novatek,nvt-ts.yaml
 F:	drivers/input/touchscreen/novatek-nvt-ts.c
 
 NSDEPS

-- 
2.45.1

[PATCH v4 3/3] Input: novatek-nvt-ts: add support for NT36672A touchscreen

[Joel Selvaraj via B4 Relay]

From: Joel Selvaraj <joelselvaraj.oss@gmail.com>

Extend the novatek touchscreen driver to support NT36672A chip which
is found in phones like qcom/sdm845-xiaomi-beryllium-tianma.dts.
Added devicetree support for the driver and used i2c chip data to handle
the variation in chip id and wake type. Also added vcc and iovcc
regulators which are used to power the touchscreen hardware.

Signed-off-by: Joel Selvaraj <joelselvaraj.oss@gmail.com>
---
 drivers/input/touchscreen/novatek-nvt-ts.c | 70 +++++++++++++++++++++++++++---
 1 file changed, 64 insertions(+), 6 deletions(-)

diff --git a/drivers/input/touchscreen/novatek-nvt-ts.c b/drivers/input/touchscreen/novatek-nvt-ts.c
index 9bee3a0c122fb..c24c33f609eb8 100644
--- a/drivers/input/touchscreen/novatek-nvt-ts.c
+++ b/drivers/input/touchscreen/novatek-nvt-ts.c
@@ -31,9 +31,6 @@
 #define NVT_TS_PARAMS_CHIP_ID		0x0e
 #define NVT_TS_PARAMS_SIZE		0x0f
 
-#define NVT_TS_SUPPORTED_WAKE_TYPE	0x05
-#define NVT_TS_SUPPORTED_CHIP_ID	0x05
-
 #define NVT_TS_MAX_TOUCHES		10
 #define NVT_TS_MAX_SIZE			4096
 
@@ -51,11 +48,18 @@ static const int nvt_ts_irq_type[4] = {
 	IRQF_TRIGGER_HIGH
 };
 
+struct nvt_ts_i2c_chip_data {
+	u8 wake_type;
+	u8 chip_id;
+};
+
 struct nvt_ts_data {
 	struct i2c_client *client;
 	struct input_dev *input;
 	struct gpio_desc *reset_gpio;
+	struct regulator_bulk_data regulators[2];
 	struct touchscreen_properties prop;
+	const struct nvt_ts_i2c_chip_data *chip;
 	int max_touches;
 	u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
 };
@@ -142,6 +146,13 @@ static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
 static int nvt_ts_start(struct input_dev *dev)
 {
 	struct nvt_ts_data *data = input_get_drvdata(dev);
+	int error;
+
+	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
+	if (error) {
+		dev_err(&data->client->dev, "failed to enable regulators\n");
+		return error;
+	}
 
 	enable_irq(data->client->irq);
 	gpiod_set_value_cansleep(data->reset_gpio, 0);
@@ -155,6 +166,7 @@ static void nvt_ts_stop(struct input_dev *dev)
 
 	disable_irq(data->client->irq);
 	gpiod_set_value_cansleep(data->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
 }
 
 static int nvt_ts_suspend(struct device *dev)
@@ -199,9 +211,31 @@ static int nvt_ts_probe(struct i2c_client *client)
 	if (!data)
 		return -ENOMEM;
 
+	data->chip = device_get_match_data(&client->dev);
+	if (!data->chip)
+		return -EINVAL;
+
 	data->client = client;
 	i2c_set_clientdata(client, data);
 
+	/*
+	 * VCC is the analog voltage supply
+	 * IOVCC is the digital voltage supply
+	 */
+	data->regulators[0].supply = "vcc";
+	data->regulators[1].supply = "iovcc";
+	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->regulators), data->regulators);
+	if (error) {
+		dev_err(dev, "cannot get regulators: %d\n", error);
+		return error;
+	}
+
+	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
+	if (error) {
+		dev_err(dev, "failed to enable regulators: %d\n", error);
+		return error;
+	}
+
 	data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
 	error = PTR_ERR_OR_ZERO(data->reset_gpio);
 	if (error) {
@@ -216,6 +250,11 @@ static int nvt_ts_probe(struct i2c_client *client)
 	gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
 	if (error)
 		return error;
+	error = regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
+	if (error) {
+		dev_err(dev, "failed to disable regulators: %d\n", error);
+		return error;
+	}
 
 	width  = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
 	height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
@@ -225,8 +264,8 @@ static int nvt_ts_probe(struct i2c_client *client)
 	if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
 	    data->max_touches > NVT_TS_MAX_TOUCHES ||
 	    irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
-	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != NVT_TS_SUPPORTED_WAKE_TYPE ||
-	    data->buf[NVT_TS_PARAMS_CHIP_ID] != NVT_TS_SUPPORTED_CHIP_ID) {
+	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != data->chip->wake_type ||
+	    data->buf[NVT_TS_PARAMS_CHIP_ID] != data->chip->chip_id) {
 		dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
 			NVT_TS_PARAMS_SIZE, data->buf);
 		return -EIO;
@@ -277,8 +316,26 @@ static int nvt_ts_probe(struct i2c_client *client)
 	return 0;
 }
 
+static const struct nvt_ts_i2c_chip_data nvt_nt11205_ts_data = {
+	.wake_type = 0x05,
+	.chip_id = 0x05,
+};
+
+static const struct nvt_ts_i2c_chip_data nvt_nt36672a_ts_data = {
+	.wake_type = 0x01,
+	.chip_id = 0x08,
+};
+
+static const struct of_device_id nvt_ts_of_match[] = {
+	{ .compatible = "novatek,nt11205-ts", .data = &nvt_nt11205_ts_data },
+	{ .compatible = "novatek,nt36672a-ts", .data = &nvt_nt36672a_ts_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, nvt_ts_of_match);
+
 static const struct i2c_device_id nvt_ts_i2c_id[] = {
-	{ "nt11205-ts" },
+	{ "nt11205-ts", (unsigned long) &nvt_nt11205_ts_data },
+	{ "nt36672a-ts", (unsigned long) &nvt_nt36672a_ts_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
@@ -287,6 +344,7 @@ static struct i2c_driver nvt_ts_driver = {
 	.driver = {
 		.name	= "novatek-nvt-ts",
 		.pm	= pm_sleep_ptr(&nvt_ts_pm_ops),
+		.of_match_table = nvt_ts_of_match,
 	},
 	.probe = nvt_ts_probe,
 	.id_table = nvt_ts_i2c_id,

-- 
2.45.1

Re: [PATCH v4 3/3] Input: novatek-nvt-ts: add support for NT36672A touchscreen

[Hans de Goede]

Hi Joel,

Thank you for the new version.

On 6/1/24 5:30 PM, Joel Selvaraj via B4 Relay wrote:
> From: Joel Selvaraj <joelselvaraj.oss@gmail.com>
> 
> Extend the novatek touchscreen driver to support NT36672A chip which
> is found in phones like qcom/sdm845-xiaomi-beryllium-tianma.dts.
> Added devicetree support for the driver and used i2c chip data to handle
> the variation in chip id and wake type. Also added vcc and iovcc
> regulators which are used to power the touchscreen hardware.
> 
> Signed-off-by: Joel Selvaraj <joelselvaraj.oss@gmail.com>
> ---
>  drivers/input/touchscreen/novatek-nvt-ts.c | 70 +++++++++++++++++++++++++++---
>  1 file changed, 64 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/novatek-nvt-ts.c b/drivers/input/touchscreen/novatek-nvt-ts.c
> index 9bee3a0c122fb..c24c33f609eb8 100644
> --- a/drivers/input/touchscreen/novatek-nvt-ts.c
> +++ b/drivers/input/touchscreen/novatek-nvt-ts.c
> @@ -31,9 +31,6 @@
>  #define NVT_TS_PARAMS_CHIP_ID		0x0e
>  #define NVT_TS_PARAMS_SIZE		0x0f
>  
> -#define NVT_TS_SUPPORTED_WAKE_TYPE	0x05
> -#define NVT_TS_SUPPORTED_CHIP_ID	0x05
> -
>  #define NVT_TS_MAX_TOUCHES		10
>  #define NVT_TS_MAX_SIZE			4096
>  
> @@ -51,11 +48,18 @@ static const int nvt_ts_irq_type[4] = {
>  	IRQF_TRIGGER_HIGH
>  };
>  
> +struct nvt_ts_i2c_chip_data {
> +	u8 wake_type;
> +	u8 chip_id;
> +};
> +
>  struct nvt_ts_data {
>  	struct i2c_client *client;
>  	struct input_dev *input;
>  	struct gpio_desc *reset_gpio;
> +	struct regulator_bulk_data regulators[2];
>  	struct touchscreen_properties prop;
> +	const struct nvt_ts_i2c_chip_data *chip;

Almost there. I have one remark which requires fixing below,
so since a v5 will be necessary anyways I also spotted another
small possible improvement:

Since you only use chip->wake_type and chip->chip_id
inside probe() you can make this chip pointer a local
variable in probe(). This saves having this stored
on the kernel heap even though it is never used again.

>  	int max_touches;
>  	u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
>  };
> @@ -142,6 +146,13 @@ static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
>  static int nvt_ts_start(struct input_dev *dev)
>  {
>  	struct nvt_ts_data *data = input_get_drvdata(dev);
> +	int error;
> +
> +	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
> +	if (error) {
> +		dev_err(&data->client->dev, "failed to enable regulators\n");
> +		return error;
> +	}
>  
>  	enable_irq(data->client->irq);
>  	gpiod_set_value_cansleep(data->reset_gpio, 0);
> @@ -155,6 +166,7 @@ static void nvt_ts_stop(struct input_dev *dev)
>  
>  	disable_irq(data->client->irq);
>  	gpiod_set_value_cansleep(data->reset_gpio, 1);
> +	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
>  }
>  
>  static int nvt_ts_suspend(struct device *dev)
> @@ -199,9 +211,31 @@ static int nvt_ts_probe(struct i2c_client *client)
>  	if (!data)
>  		return -ENOMEM;
>  
> +	data->chip = device_get_match_data(&client->dev);
> +	if (!data->chip)
> +		return -EINVAL;
> +

As mentioned above instead of data->chip you can use a local
"chip" variable here.

>  	data->client = client;
>  	i2c_set_clientdata(client, data);
>  
> +	/*
> +	 * VCC is the analog voltage supply
> +	 * IOVCC is the digital voltage supply
> +	 */
> +	data->regulators[0].supply = "vcc";
> +	data->regulators[1].supply = "iovcc";
> +	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->regulators), data->regulators);
> +	if (error) {
> +		dev_err(dev, "cannot get regulators: %d\n", error);
> +		return error;
> +	}
> +
> +	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
> +	if (error) {
> +		dev_err(dev, "failed to enable regulators: %d\n", error);
> +		return error;
> +	}
> +
>  	data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>  	error = PTR_ERR_OR_ZERO(data->reset_gpio);
>  	if (error) {

Almost there. You need to disable the regulators when probe fails to
avoid an error from the regulator core about unbalanced enable/disable
of the regulators when the devm framework releases them.

So you need to add a regulator_bulk_disable() call in
the "if (error) {" branch here:

  	data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
  	error = PTR_ERR_OR_ZERO(data->reset_gpio);
  	if (error) {
		regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
		dev_err(dev, "failed to request reset GPIO: %d\n", error);
		return error;
	}

And ... (continued below)

> @@ -216,6 +250,11 @@ static int nvt_ts_probe(struct i2c_client *client)
>  	gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
>  	if (error)
>  		return error;
> +	error = regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);

I would not error check this, just like how it is not error checked
in void nvt_ts_stop() and then I would move it to above the error
checking for the nvt_ts_read_data(...NVT_TS_PARAMETERS...), to avoid
the need for an extra regulator_bulk_disable() call in the if (error)
path for the nvt_ts_read_data() call.

So make the code look like this:

        error = nvt_ts_read_data(data->client, NVT_TS_PARAMETERS_START,
                                 data->buf, NVT_TS_PARAMS_SIZE);
        gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
        if (error)
                return error;

        width  = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
        height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
	...

This way you only need one extra regulator_bulk_disable() call for
error-exit paths in the case of devm_gpiod_get(dev, "reset", ...)
failing.

Regards,

Hans






> @@ -225,8 +264,8 @@ static int nvt_ts_probe(struct i2c_client *client)
>  	if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
>  	    data->max_touches > NVT_TS_MAX_TOUCHES ||
>  	    irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
> -	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != NVT_TS_SUPPORTED_WAKE_TYPE ||
> -	    data->buf[NVT_TS_PARAMS_CHIP_ID] != NVT_TS_SUPPORTED_CHIP_ID) {
> +	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != data->chip->wake_type ||
> +	    data->buf[NVT_TS_PARAMS_CHIP_ID] != data->chip->chip_id) {
>  		dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
>  			NVT_TS_PARAMS_SIZE, data->buf);
>  		return -EIO;
> @@ -277,8 +316,26 @@ static int nvt_ts_probe(struct i2c_client *client)
>  	return 0;
>  }
>  
> +static const struct nvt_ts_i2c_chip_data nvt_nt11205_ts_data = {
> +	.wake_type = 0x05,
> +	.chip_id = 0x05,
> +};
> +
> +static const struct nvt_ts_i2c_chip_data nvt_nt36672a_ts_data = {
> +	.wake_type = 0x01,
> +	.chip_id = 0x08,
> +};
> +
> +static const struct of_device_id nvt_ts_of_match[] = {
> +	{ .compatible = "novatek,nt11205-ts", .data = &nvt_nt11205_ts_data },
> +	{ .compatible = "novatek,nt36672a-ts", .data = &nvt_nt36672a_ts_data },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, nvt_ts_of_match);
> +
>  static const struct i2c_device_id nvt_ts_i2c_id[] = {
> -	{ "nt11205-ts" },
> +	{ "nt11205-ts", (unsigned long) &nvt_nt11205_ts_data },
> +	{ "nt36672a-ts", (unsigned long) &nvt_nt36672a_ts_data },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
> @@ -287,6 +344,7 @@ static struct i2c_driver nvt_ts_driver = {
>  	.driver = {
>  		.name	= "novatek-nvt-ts",
>  		.pm	= pm_sleep_ptr(&nvt_ts_pm_ops),
> +		.of_match_table = nvt_ts_of_match,
>  	},
>  	.probe = nvt_ts_probe,
>  	.id_table = nvt_ts_i2c_id,
> 

Re: [PATCH v4 3/3] Input: novatek-nvt-ts: add support for NT36672A touchscreen

[Joel Selvaraj]

Hi Hans,

On 6/1/24 12:07, Hans de Goede wrote:
> Hi Joel,
> 
> Thank you for the new version.
> 
> On 6/1/24 5:30 PM, Joel Selvaraj via B4 Relay wrote:
>> From: Joel Selvaraj <joelselvaraj.oss@gmail.com>
>>
>> Extend the novatek touchscreen driver to support NT36672A chip which
>> is found in phones like qcom/sdm845-xiaomi-beryllium-tianma.dts.
>> Added devicetree support for the driver and used i2c chip data to handle
>> the variation in chip id and wake type. Also added vcc and iovcc
>> regulators which are used to power the touchscreen hardware.
>>
>> Signed-off-by: Joel Selvaraj <joelselvaraj.oss@gmail.com>
>> ---
>>   drivers/input/touchscreen/novatek-nvt-ts.c | 70 +++++++++++++++++++++++++++---
>>   1 file changed, 64 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/input/touchscreen/novatek-nvt-ts.c b/drivers/input/touchscreen/novatek-nvt-ts.c
>> index 9bee3a0c122fb..c24c33f609eb8 100644
>> --- a/drivers/input/touchscreen/novatek-nvt-ts.c
>> +++ b/drivers/input/touchscreen/novatek-nvt-ts.c
>> @@ -31,9 +31,6 @@
>>   #define NVT_TS_PARAMS_CHIP_ID		0x0e
>>   #define NVT_TS_PARAMS_SIZE		0x0f
>>   
>> -#define NVT_TS_SUPPORTED_WAKE_TYPE	0x05
>> -#define NVT_TS_SUPPORTED_CHIP_ID	0x05
>> -
>>   #define NVT_TS_MAX_TOUCHES		10
>>   #define NVT_TS_MAX_SIZE			4096
>>   
>> @@ -51,11 +48,18 @@ static const int nvt_ts_irq_type[4] = {
>>   	IRQF_TRIGGER_HIGH
>>   };
>>   
>> +struct nvt_ts_i2c_chip_data {
>> +	u8 wake_type;
>> +	u8 chip_id;
>> +};
>> +
>>   struct nvt_ts_data {
>>   	struct i2c_client *client;
>>   	struct input_dev *input;
>>   	struct gpio_desc *reset_gpio;
>> +	struct regulator_bulk_data regulators[2];
>>   	struct touchscreen_properties prop;
>> +	const struct nvt_ts_i2c_chip_data *chip;
> 
> Almost there. I have one remark which requires fixing below,
> so since a v5 will be necessary anyways I also spotted another
> small possible improvement:
> 
> Since you only use chip->wake_type and chip->chip_id
> inside probe() you can make this chip pointer a local
> variable in probe(). This saves having this stored
> on the kernel heap even though it is never used again.
> 

Thanks for your detailed explanation here and below. I will fix them in v5.

Regards,
Joel

>>   	int max_touches;
>>   	u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
>>   };
>> @@ -142,6 +146,13 @@ static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
>>   static int nvt_ts_start(struct input_dev *dev)
>>   {
>>   	struct nvt_ts_data *data = input_get_drvdata(dev);
>> +	int error;
>> +
>> +	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
>> +	if (error) {
>> +		dev_err(&data->client->dev, "failed to enable regulators\n");
>> +		return error;
>> +	}
>>   
>>   	enable_irq(data->client->irq);
>>   	gpiod_set_value_cansleep(data->reset_gpio, 0);
>> @@ -155,6 +166,7 @@ static void nvt_ts_stop(struct input_dev *dev)
>>   
>>   	disable_irq(data->client->irq);
>>   	gpiod_set_value_cansleep(data->reset_gpio, 1);
>> +	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
>>   }
>>   
>>   static int nvt_ts_suspend(struct device *dev)
>> @@ -199,9 +211,31 @@ static int nvt_ts_probe(struct i2c_client *client)
>>   	if (!data)
>>   		return -ENOMEM;
>>   
>> +	data->chip = device_get_match_data(&client->dev);
>> +	if (!data->chip)
>> +		return -EINVAL;
>> +
> 
> As mentioned above instead of data->chip you can use a local
> "chip" variable here.
> 
>>   	data->client = client;
>>   	i2c_set_clientdata(client, data);
>>   
>> +	/*
>> +	 * VCC is the analog voltage supply
>> +	 * IOVCC is the digital voltage supply
>> +	 */
>> +	data->regulators[0].supply = "vcc";
>> +	data->regulators[1].supply = "iovcc";
>> +	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->regulators), data->regulators);
>> +	if (error) {
>> +		dev_err(dev, "cannot get regulators: %d\n", error);
>> +		return error;
>> +	}
>> +
>> +	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
>> +	if (error) {
>> +		dev_err(dev, "failed to enable regulators: %d\n", error);
>> +		return error;
>> +	}
>> +
>>   	data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>>   	error = PTR_ERR_OR_ZERO(data->reset_gpio);
>>   	if (error) {
> 
> Almost there. You need to disable the regulators when probe fails to
> avoid an error from the regulator core about unbalanced enable/disable
> of the regulators when the devm framework releases them.
> 
> So you need to add a regulator_bulk_disable() call in
> the "if (error) {" branch here:
> 
>    	data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>    	error = PTR_ERR_OR_ZERO(data->reset_gpio);
>    	if (error) {
> 		regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
> 		dev_err(dev, "failed to request reset GPIO: %d\n", error);
> 		return error;
> 	}
> 
> And ... (continued below)
> 
>> @@ -216,6 +250,11 @@ static int nvt_ts_probe(struct i2c_client *client)
>>   	gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
>>   	if (error)
>>   		return error;
>> +	error = regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
> 
> I would not error check this, just like how it is not error checked
> in void nvt_ts_stop() and then I would move it to above the error
> checking for the nvt_ts_read_data(...NVT_TS_PARAMETERS...), to avoid
> the need for an extra regulator_bulk_disable() call in the if (error)
> path for the nvt_ts_read_data() call.
> 
> So make the code look like this:
> 
>          error = nvt_ts_read_data(data->client, NVT_TS_PARAMETERS_START,
>                                   data->buf, NVT_TS_PARAMS_SIZE);
>          gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
> 	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
>          if (error)
>                  return error;
> 
>          width  = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
>          height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
> 	...
> 
> This way you only need one extra regulator_bulk_disable() call for
> error-exit paths in the case of devm_gpiod_get(dev, "reset", ...)
> failing.
> 
> Regards,
> 
> Hans
> 
> 
> 
> 
> 
> 
>> @@ -225,8 +264,8 @@ static int nvt_ts_probe(struct i2c_client *client)
>>   	if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
>>   	    data->max_touches > NVT_TS_MAX_TOUCHES ||
>>   	    irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
>> -	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != NVT_TS_SUPPORTED_WAKE_TYPE ||
>> -	    data->buf[NVT_TS_PARAMS_CHIP_ID] != NVT_TS_SUPPORTED_CHIP_ID) {
>> +	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != data->chip->wake_type ||
>> +	    data->buf[NVT_TS_PARAMS_CHIP_ID] != data->chip->chip_id) {
>>   		dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
>>   			NVT_TS_PARAMS_SIZE, data->buf);
>>   		return -EIO;
>> @@ -277,8 +316,26 @@ static int nvt_ts_probe(struct i2c_client *client)
>>   	return 0;
>>   }
>>   
>> +static const struct nvt_ts_i2c_chip_data nvt_nt11205_ts_data = {
>> +	.wake_type = 0x05,
>> +	.chip_id = 0x05,
>> +};
>> +
>> +static const struct nvt_ts_i2c_chip_data nvt_nt36672a_ts_data = {
>> +	.wake_type = 0x01,
>> +	.chip_id = 0x08,
>> +};
>> +
>> +static const struct of_device_id nvt_ts_of_match[] = {
>> +	{ .compatible = "novatek,nt11205-ts", .data = &nvt_nt11205_ts_data },
>> +	{ .compatible = "novatek,nt36672a-ts", .data = &nvt_nt36672a_ts_data },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(of, nvt_ts_of_match);
>> +
>>   static const struct i2c_device_id nvt_ts_i2c_id[] = {
>> -	{ "nt11205-ts" },
>> +	{ "nt11205-ts", (unsigned long) &nvt_nt11205_ts_data },
>> +	{ "nt36672a-ts", (unsigned long) &nvt_nt36672a_ts_data },
>>   	{ }
>>   };
>>   MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
>> @@ -287,6 +344,7 @@ static struct i2c_driver nvt_ts_driver = {
>>   	.driver = {
>>   		.name	= "novatek-nvt-ts",
>>   		.pm	= pm_sleep_ptr(&nvt_ts_pm_ops),
>> +		.of_match_table = nvt_ts_of_match,
>>   	},
>>   	.probe = nvt_ts_probe,
>>   	.id_table = nvt_ts_i2c_id,
>>
>