[PATCH v5 0/3] Input: atmel_mxt_ts: Add support for optional regulators

[PATCH v5 0/3] Input: atmel_mxt_ts: Add support for optional regulators

[Paweł Chmiel]

This patch series adds optional regulator support to atmel_mxt_ts.
First patch adds regulators to driver.
Second patch ensures that device is ready for communication.
Third patch updates documentation.

Changes from v4:
  - Add missing regulator_disable for vdd in case of error,
    when enabling avdd regulator

Changes from v3:
  - Checkpatch fixes
  - Drop punctuation from subject of one of patches

Changes from v2:
  - Add reviewed-by to one patch
  - Move code for enabling regulators into separate method,
    to make code more readable.
  - Add wait code, to ensure that device is ready for communication.

Changes from v1:
  - Enable regulators only if reset_gpio is present.
  - Switch from devm_regulator_get_optional to devm_regulator_get.

Paweł Chmiel (3):
  Input: atmel_mxt_ts: Add support for  optional regulators
  Input: atmel_mxt_ts: Wait for device be ready for communication
  Input: atmel_mxt_ts: Document optional voltage regulators

 .../bindings/input/atmel,maxtouch.txt         |  8 ++
 drivers/input/touchscreen/atmel_mxt_ts.c      | 78 +++++++++++++++++--
 2 files changed, 80 insertions(+), 6 deletions(-)

-- 
2.17.1

[PATCH v5 1/3] Input: atmel_mxt_ts: Add support for optional regulators

[Paweł Chmiel]

This patch adds optional regulators, which can be used to power
up touchscreen. After enabling regulators, we need to wait 150msec.
This value is taken from official driver.

It was tested on Samsung Galaxy i9000 (based on Samsung S5PV210 SOC).

Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
---
Changes from v4:
  - Add missing regulator_disable for vdd in case of error,
    when enabling avdd regulator

Changes from v3:
  - Fix checkpatch issues
  - Drop sentence punctuation from patch subject

Changes from v2:
  - Move code enabling regulators into separate method,
    to make code more readable.

Changes from v1:
  - Enable regulators only if reset_gpio is present.
  - Switch from devm_regulator_get_optional to devm_regulator_get
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 67 +++++++++++++++++++++---
 1 file changed, 61 insertions(+), 6 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index d3aacd534e9c..55a107fc1b73 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -27,6 +27,7 @@
 #include <linux/interrupt.h>
 #include <linux/of.h>
 #include <linux/property.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/gpio/consumer.h>
 #include <asm/unaligned.h>
@@ -194,10 +195,10 @@ enum t100_type {
 
 /* Delay times */
 #define MXT_BACKUP_TIME		50	/* msec */
-#define MXT_RESET_GPIO_TIME	20	/* msec */
 #define MXT_RESET_INVALID_CHG	100	/* msec */
 #define MXT_RESET_TIME		200	/* msec */
 #define MXT_RESET_TIMEOUT	3000	/* msec */
+#define MXT_REGULATOR_DELAY	150	/* msec */
 #define MXT_CRC_TIMEOUT		1000	/* msec */
 #define MXT_FW_RESET_TIME	3000	/* msec */
 #define MXT_FW_CHG_TIMEOUT	300	/* msec */
@@ -323,6 +324,8 @@ struct mxt_data {
 	struct t7_config t7_cfg;
 	struct mxt_dbg dbg;
 	struct gpio_desc *reset_gpio;
+	struct regulator *vdd_reg;
+	struct regulator *avdd_reg;
 
 	/* Cached parameters from object table */
 	u16 T5_address;
@@ -3038,6 +3041,40 @@ static const struct dmi_system_id chromebook_T9_suspend_dmi[] = {
 	{ }
 };
 
+static int mxt_regulator_enable(struct mxt_data *data)
+{
+	int error;
+
+	if (data->reset_gpio) {
+		error = regulator_enable(data->vdd_reg);
+		if (error) {
+			dev_err(&data->client->dev,
+				"Failed to enable vdd regulator: %d\n", error);
+			return error;
+		}
+
+		error = regulator_enable(data->avdd_reg);
+		if (error) {
+			regulator_disable(data->vdd_reg);
+
+			dev_err(&data->client->dev,
+				"Failed to enable avdd regulator: %d\n", error);
+			return error;
+		}
+
+		/*
+		 * According to maXTouch power sequencing specification,
+		 * RESET line must be kept low until some time
+		 * after regulators come up to voltage
+		 */
+		msleep(MXT_REGULATOR_DELAY);
+		gpiod_set_value(data->reset_gpio, 1);
+		msleep(MXT_RESET_INVALID_CHG);
+	}
+
+	return 0;
+}
+
 static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct mxt_data *data;
@@ -3098,6 +3135,22 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		return error;
 	}
 
+	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
+	if (IS_ERR(data->vdd_reg)) {
+		error = PTR_ERR(data->vdd_reg);
+		dev_err(&client->dev, "Failed to get vdd regulator: %d\n",
+			error);
+		return error;
+	}
+
+	data->avdd_reg = devm_regulator_get(&client->dev, "avdd");
+	if (IS_ERR(data->avdd_reg)) {
+		error = PTR_ERR(data->avdd_reg);
+		dev_err(&client->dev, "Failed to get avdd regulator: %d\n",
+			error);
+		return error;
+	}
+
 	error = devm_request_threaded_irq(&client->dev, client->irq,
 					  NULL, mxt_interrupt, IRQF_ONESHOT,
 					  client->name, data);
@@ -3108,11 +3161,9 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	disable_irq(client->irq);
 
-	if (data->reset_gpio) {
-		msleep(MXT_RESET_GPIO_TIME);
-		gpiod_set_value(data->reset_gpio, 1);
-		msleep(MXT_RESET_INVALID_CHG);
-	}
+	error = mxt_regulator_enable(data);
+	if (error)
+		return error;
 
 	error = mxt_initialize(data);
 	if (error)
@@ -3138,6 +3189,10 @@ static int mxt_remove(struct i2c_client *client)
 	struct mxt_data *data = i2c_get_clientdata(client);
 
 	disable_irq(data->irq);
+	if (data->reset_gpio) {
+		regulator_disable(data->avdd_reg);
+		regulator_disable(data->vdd_reg);
+	}
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
 	mxt_free_input_device(data);
 	mxt_free_object_table(data);
-- 
2.17.1

[PATCH v5 2/3] Input: atmel_mxt_ts: Wait for device be ready for communication

[Paweł Chmiel]

According to documentation, device isn't ready for communication,
until firmware asserts the CHG line. Add missing wait for this.

Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
---
Changes from v1:
  - Fix checkpatch issues
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 55a107fc1b73..e8949c6ceafa 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -202,6 +202,7 @@ enum t100_type {
 #define MXT_CRC_TIMEOUT		1000	/* msec */
 #define MXT_FW_RESET_TIME	3000	/* msec */
 #define MXT_FW_CHG_TIMEOUT	300	/* msec */
+#define MXT_POWERON_DELAY	150	/* msec */
 
 /* Command to unlock bootloader */
 #define MXT_UNLOCK_CMD_MSB	0xaa
@@ -3070,6 +3071,16 @@ static int mxt_regulator_enable(struct mxt_data *data)
 		msleep(MXT_REGULATOR_DELAY);
 		gpiod_set_value(data->reset_gpio, 1);
 		msleep(MXT_RESET_INVALID_CHG);
+
+retry_wait:
+		reinit_completion(&data->bl_completion);
+		data->in_bootloader = true;
+		error = mxt_wait_for_completion(data, &data->bl_completion,
+						MXT_POWERON_DELAY);
+		if (error == -EINTR)
+			goto retry_wait;
+
+		data->in_bootloader = false;
 	}
 
 	return 0;
-- 
2.17.1

[PATCH v5 3/3] Input: atmel_mxt_ts: Document optional voltage regulators

[Paweł Chmiel]

Document new optional voltage regulators, which can be used
to power down/up touchscreen.

Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
Changes from v1:
  - Added reviewed-by
---
 .../devicetree/bindings/input/atmel,maxtouch.txt          | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
index c88919480d37..17930ecadad3 100644
--- a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
+++ b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
@@ -31,6 +31,12 @@ Optional properties for main touchpad device:
 
 - reset-gpios: GPIO specifier for the touchscreen's reset pin (active low)
 
+- avdd-supply: Analog power supply. It powers up the analog channel block
+    of the controller to detect the touches.
+
+- vdd-supply: Digital power supply. It powers up the digital block
+    of the controller to enable i2c communication.
+
 Example:
 
 	touch@4b {
@@ -38,4 +44,6 @@ Example:
 		reg = <0x4b>;
 		interrupt-parent = <&gpio>;
 		interrupts = <TEGRA_GPIO(W, 3) IRQ_TYPE_LEVEL_LOW>;
+		avdd-supply = <&atsp_reg>;
+		vdd-supply = <&tsp_reg>;
 	};
-- 
2.17.1

Re: [PATCH v5 3/3] Input: atmel_mxt_ts: Document optional voltage regulators

[Sebastian Reichel]

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Hi,

On Fri, Dec 14, 2018 at 04:12:14PM +0100, Paweł Chmiel wrote:
> Document new optional voltage regulators, which can be used
> to power down/up touchscreen.
> 
> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
> Reviewed-by: Rob Herring <robh@kernel.org>

Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>

-- Sebastian

> ---
> Changes from v1:
>   - Added reviewed-by
> ---
>  .../devicetree/bindings/input/atmel,maxtouch.txt          | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
> index c88919480d37..17930ecadad3 100644
> --- a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
> +++ b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
> @@ -31,6 +31,12 @@ Optional properties for main touchpad device:
>  
>  - reset-gpios: GPIO specifier for the touchscreen's reset pin (active low)
>  
> +- avdd-supply: Analog power supply. It powers up the analog channel block
> +    of the controller to detect the touches.
> +
> +- vdd-supply: Digital power supply. It powers up the digital block
> +    of the controller to enable i2c communication.
> +
>  Example:
>  
>  	touch@4b {
> @@ -38,4 +44,6 @@ Example:
>  		reg = <0x4b>;
>  		interrupt-parent = <&gpio>;
>  		interrupts = <TEGRA_GPIO(W, 3) IRQ_TYPE_LEVEL_LOW>;
> +		avdd-supply = <&atsp_reg>;
> +		vdd-supply = <&tsp_reg>;
>  	};
> -- 
> 2.17.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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Re: [PATCH v5 2/3] Input: atmel_mxt_ts: Wait for device be ready for communication

[Dmitry Torokhov]

On Fri, Dec 14, 2018 at 04:12:13PM +0100, Paweł Chmiel wrote:
> According to documentation, device isn't ready for communication,
> until firmware asserts the CHG line. Add missing wait for this.
> 
> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
> ---
> Changes from v1:
>   - Fix checkpatch issues
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 55a107fc1b73..e8949c6ceafa 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -202,6 +202,7 @@ enum t100_type {
>  #define MXT_CRC_TIMEOUT		1000	/* msec */
>  #define MXT_FW_RESET_TIME	3000	/* msec */
>  #define MXT_FW_CHG_TIMEOUT	300	/* msec */
> +#define MXT_POWERON_DELAY	150	/* msec */
>  
>  /* Command to unlock bootloader */
>  #define MXT_UNLOCK_CMD_MSB	0xaa
> @@ -3070,6 +3071,16 @@ static int mxt_regulator_enable(struct mxt_data *data)
>  		msleep(MXT_REGULATOR_DELAY);
>  		gpiod_set_value(data->reset_gpio, 1);
>  		msleep(MXT_RESET_INVALID_CHG);
> +
> +retry_wait:
> +		reinit_completion(&data->bl_completion);
> +		data->in_bootloader = true;

I think you would want to reinit the ocmpletion and set the flag before
releasing reset line and sleeping, otherwise if interrupt fires too
early you'll be spinning for extra time.

I'd also really want to hear from Nick on this change.

> +		error = mxt_wait_for_completion(data, &data->bl_completion,
> +						MXT_POWERON_DELAY);
> +		if (error == -EINTR)
> +			goto retry_wait;
> +
> +		data->in_bootloader = false;
>  	}
>  
>  	return 0;
> -- 
> 2.17.1
> 

Thanks.

-- 
Dmitry