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* [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler
@ 2020-11-04 15:30 Linus Walleij
  2020-11-04 15:59 ` Philippe Schenker
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Linus Walleij @ 2020-11-04 15:30 UTC (permalink / raw)
  To: Dmitry Torokhov, linux-input
  Cc: linux-samsung-soc, Linus Walleij, Krzysztof Kozlowski,
	NXP Linux Team, Pengutronix Kernel Team, linux-tegra,
	linux-arm-kernel

This driver uses GPIO descriptors to drive the touchscreen
RESET line. In the existing device trees this has in
conflict with intution been flagged as GPIO_ACTIVE_HIGH
and the driver then applies the reverse action by
driving the line low (setting to 0) to enter
reset state and driving the line high (setting to 1) to
get out of reset state.

The correct way to handle active low GPIO lines is to
provide the GPIO_ACTIVE_LOW in the device tree (thus
properly describing the hardware) and letting the GPIO
framework invert the assertion (driving high) to a low
level and vice versa.

This is considered a bug since the device trees are
incorrectly mis-specifying the line as active high.

Fix the driver and all device trees specifying a reset
line.

Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-tegra@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v1->v2:
- New patch fixing this confusion before adding the
  new YAML bindings.
- CC some misc maintainers and mailing lists that should
  be aware that we do this change.
---
 arch/arm/boot/dts/imx53-ppd.dts                 | 2 +-
 arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts    | 2 +-
 arch/arm/boot/dts/imx6q-apalis-eval.dts         | 2 +-
 arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts   | 2 +-
 arch/arm/boot/dts/imx6q-apalis-ixora.dts        | 2 +-
 arch/arm/boot/dts/imx7-colibri-aster.dtsi       | 2 +-
 arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi     | 2 +-
 arch/arm/boot/dts/motorola-mapphone-common.dtsi | 2 +-
 arch/arm/boot/dts/s5pv210-aries.dtsi            | 2 +-
 arch/arm/boot/dts/tegra20-acer-a500-picasso.dts | 2 +-
 drivers/input/touchscreen/atmel_mxt_ts.c        | 6 ++++--
 11 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/arch/arm/boot/dts/imx53-ppd.dts b/arch/arm/boot/dts/imx53-ppd.dts
index f7dcdf96e5c0..8f4a63ea912e 100644
--- a/arch/arm/boot/dts/imx53-ppd.dts
+++ b/arch/arm/boot/dts/imx53-ppd.dts
@@ -589,7 +589,7 @@ &i2c2 {
 
 	touchscreen@4b {
 		compatible = "atmel,maxtouch";
-		reset-gpio = <&gpio5 19 GPIO_ACTIVE_HIGH>;
+		reset-gpio = <&gpio5 19 GPIO_ACTIVE_LOW>;
 		reg = <0x4b>;
 		interrupt-parent = <&gpio5>;
 		interrupts = <4 IRQ_TYPE_LEVEL_LOW>;
diff --git a/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts b/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts
index 65359aece950..7da74e6f46d9 100644
--- a/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts
+++ b/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts
@@ -143,7 +143,7 @@ touchscreen@4a {
 		reg = <0x4a>;
 		interrupt-parent = <&gpio1>;
 		interrupts = <9 IRQ_TYPE_EDGE_FALLING>;		/* SODIMM 28 */
-		reset-gpios = <&gpio2 10 GPIO_ACTIVE_HIGH>;	/* SODIMM 30 */
+		reset-gpios = <&gpio2 10 GPIO_ACTIVE_LOW>;	/* SODIMM 30 */
 		status = "disabled";
 	};
 
diff --git a/arch/arm/boot/dts/imx6q-apalis-eval.dts b/arch/arm/boot/dts/imx6q-apalis-eval.dts
index fab83abb6466..a0683b4aeca1 100644
--- a/arch/arm/boot/dts/imx6q-apalis-eval.dts
+++ b/arch/arm/boot/dts/imx6q-apalis-eval.dts
@@ -140,7 +140,7 @@ touchscreen@4a {
 		reg = <0x4a>;
 		interrupt-parent = <&gpio6>;
 		interrupts = <10 IRQ_TYPE_EDGE_FALLING>;
-		reset-gpios = <&gpio6 9 GPIO_ACTIVE_HIGH>; /* SODIMM 13 */
+		reset-gpios = <&gpio6 9 GPIO_ACTIVE_LOW>; /* SODIMM 13 */
 		status = "disabled";
 	};
 
diff --git a/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts b/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts
index 1614b1ae501d..86e84781cf5d 100644
--- a/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts
+++ b/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts
@@ -145,7 +145,7 @@ touchscreen@4a {
 		reg = <0x4a>;
 		interrupt-parent = <&gpio6>;
 		interrupts = <10 IRQ_TYPE_EDGE_FALLING>;
-		reset-gpios = <&gpio6 9 GPIO_ACTIVE_HIGH>; /* SODIMM 13 */
+		reset-gpios = <&gpio6 9 GPIO_ACTIVE_LOW>; /* SODIMM 13 */
 		status = "disabled";
 	};
 
diff --git a/arch/arm/boot/dts/imx6q-apalis-ixora.dts b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
index fa9f98dd15ac..62e72773e53b 100644
--- a/arch/arm/boot/dts/imx6q-apalis-ixora.dts
+++ b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
@@ -144,7 +144,7 @@ touchscreen@4a {
 		reg = <0x4a>;
 		interrupt-parent = <&gpio6>;
 		interrupts = <10 IRQ_TYPE_EDGE_FALLING>;
-		reset-gpios = <&gpio6 9 GPIO_ACTIVE_HIGH>; /* SODIMM 13 */
+		reset-gpios = <&gpio6 9 GPIO_ACTIVE_LOW>; /* SODIMM 13 */
 		status = "disabled";
 	};
 
diff --git a/arch/arm/boot/dts/imx7-colibri-aster.dtsi b/arch/arm/boot/dts/imx7-colibri-aster.dtsi
index 9fa701bec2ec..139188eb9f40 100644
--- a/arch/arm/boot/dts/imx7-colibri-aster.dtsi
+++ b/arch/arm/boot/dts/imx7-colibri-aster.dtsi
@@ -99,7 +99,7 @@ touchscreen@4a {
 		reg = <0x4a>;
 		interrupt-parent = <&gpio2>;
 		interrupts = <15 IRQ_TYPE_EDGE_FALLING>;	/* SODIMM 107 */
-		reset-gpios = <&gpio2 28 GPIO_ACTIVE_HIGH>;	/* SODIMM 106 */
+		reset-gpios = <&gpio2 28 GPIO_ACTIVE_LOW>;	/* SODIMM 106 */
 	};
 
 	/* M41T0M6 real time clock on carrier board */
diff --git a/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi b/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
index 97601375f264..3caf450735d7 100644
--- a/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
+++ b/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
@@ -124,7 +124,7 @@ touchscreen@4a {
 		reg = <0x4a>;
 		interrupt-parent = <&gpio1>;
 		interrupts = <9 IRQ_TYPE_EDGE_FALLING>;		/* SODIMM 28 */
-		reset-gpios = <&gpio1 10 GPIO_ACTIVE_HIGH>;	/* SODIMM 30 */
+		reset-gpios = <&gpio1 10 GPIO_ACTIVE_LOW>;	/* SODIMM 30 */
 		status = "disabled";
 	};
 
diff --git a/arch/arm/boot/dts/motorola-mapphone-common.dtsi b/arch/arm/boot/dts/motorola-mapphone-common.dtsi
index d5ded4f794df..5f8f77cfbe59 100644
--- a/arch/arm/boot/dts/motorola-mapphone-common.dtsi
+++ b/arch/arm/boot/dts/motorola-mapphone-common.dtsi
@@ -430,7 +430,7 @@ touchscreen@4a {
 		pinctrl-names = "default";
 		pinctrl-0 = <&touchscreen_pins>;
 
-		reset-gpios = <&gpio6 13 GPIO_ACTIVE_HIGH>; /* gpio173 */
+		reset-gpios = <&gpio6 13 GPIO_ACTIVE_LOW>; /* gpio173 */
 
 		/* gpio_183 with sys_nirq2 pad as wakeup */
 		interrupts-extended = <&gpio6 23 IRQ_TYPE_LEVEL_LOW>,
diff --git a/arch/arm/boot/dts/s5pv210-aries.dtsi b/arch/arm/boot/dts/s5pv210-aries.dtsi
index bd4450dbdcb6..4da33d0f2748 100644
--- a/arch/arm/boot/dts/s5pv210-aries.dtsi
+++ b/arch/arm/boot/dts/s5pv210-aries.dtsi
@@ -632,7 +632,7 @@ touchscreen@4a {
 		interrupts = <5 IRQ_TYPE_EDGE_FALLING>;
 		pinctrl-names = "default";
 		pinctrl-0 = <&ts_irq>;
-		reset-gpios = <&gpj1 3 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&gpj1 3 GPIO_ACTIVE_LOW>;
 	};
 };
 
diff --git a/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts b/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts
index a0b829738e8f..10794a870776 100644
--- a/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts
+++ b/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts
@@ -446,7 +446,7 @@ touchscreen@4c {
 			interrupt-parent = <&gpio>;
 			interrupts = <TEGRA_GPIO(V, 6) IRQ_TYPE_LEVEL_LOW>;
 
-			reset-gpios = <&gpio TEGRA_GPIO(Q, 7) GPIO_ACTIVE_HIGH>;
+			reset-gpios = <&gpio TEGRA_GPIO(Q, 7) GPIO_ACTIVE_LOW>;
 
 			avdd-supply = <&vdd_3v3_sys>;
 			vdd-supply  = <&vdd_3v3_sys>;
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 98f17fa3a892..ef7915400c9f 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -3134,8 +3134,9 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (error)
 		return error;
 
+	/* Request the RESET line as asserted so we go into reset */
 	data->reset_gpio = devm_gpiod_get_optional(&client->dev,
-						   "reset", GPIOD_OUT_LOW);
+						   "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(data->reset_gpio)) {
 		error = PTR_ERR(data->reset_gpio);
 		dev_err(&client->dev, "Failed to get reset gpio: %d\n", error);
@@ -3153,8 +3154,9 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	disable_irq(client->irq);
 
 	if (data->reset_gpio) {
+		/* Wait a while and then de-assert the RESET GPIO line */
 		msleep(MXT_RESET_GPIO_TIME);
-		gpiod_set_value(data->reset_gpio, 1);
+		gpiod_set_value(data->reset_gpio, 0);
 		msleep(MXT_RESET_INVALID_CHG);
 	}
 
-- 
2.26.2


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^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler
  2020-11-04 15:30 [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler Linus Walleij
@ 2020-11-04 15:59 ` Philippe Schenker
  2020-11-05  8:09 ` Krzysztof Kozlowski
  2020-11-23  6:48 ` Dmitry Torokhov
  2 siblings, 0 replies; 4+ messages in thread
From: Philippe Schenker @ 2020-11-04 15:59 UTC (permalink / raw)
  To: dmitry.torokhov, linux-input, linus.walleij
  Cc: linux-samsung-soc, krzk, linux-imx, kernel, linux-tegra,
	linux-arm-kernel

On Wed, 2020-11-04 at 16:30 +0100, Linus Walleij wrote:
> This driver uses GPIO descriptors to drive the touchscreen
> RESET line. In the existing device trees this has in
> conflict with intution been flagged as GPIO_ACTIVE_HIGH
> and the driver then applies the reverse action by
> driving the line low (setting to 0) to enter
> reset state and driving the line high (setting to 1) to
> get out of reset state.
> 
> The correct way to handle active low GPIO lines is to
> provide the GPIO_ACTIVE_LOW in the device tree (thus
> properly describing the hardware) and letting the GPIO
> framework invert the assertion (driving high) to a low
> level and vice versa.
> 
> This is considered a bug since the device trees are
> incorrectly mis-specifying the line as active high.
> 
> Fix the driver and all device trees specifying a reset
> line.
> 
> Cc: Krzysztof Kozlowski <krzk@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-tegra@vger.kernel.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: NXP Linux Team <linux-imx@nxp.com>
> Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Thanks for fixing this!

Reviewed-by: Philippe Schenker <philippe.schenker@toradex.com>

> ---
> ChangeLog v1->v2:
> - New patch fixing this confusion before adding the
>   new YAML bindings.
> - CC some misc maintainers and mailing lists that should
>   be aware that we do this change.
> ---
>  arch/arm/boot/dts/imx53-ppd.dts                 | 2 +-
>  arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts    | 2 +-
>  arch/arm/boot/dts/imx6q-apalis-eval.dts         | 2 +-
>  arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts   | 2 +-
>  arch/arm/boot/dts/imx6q-apalis-ixora.dts        | 2 +-
>  arch/arm/boot/dts/imx7-colibri-aster.dtsi       | 2 +-
>  arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi     | 2 +-
>  arch/arm/boot/dts/motorola-mapphone-common.dtsi | 2 +-
>  arch/arm/boot/dts/s5pv210-aries.dtsi            | 2 +-
>  arch/arm/boot/dts/tegra20-acer-a500-picasso.dts | 2 +-
>  drivers/input/touchscreen/atmel_mxt_ts.c        | 6 ++++--
>  11 files changed, 14 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/imx53-ppd.dts
> b/arch/arm/boot/dts/imx53-ppd.dts
> index f7dcdf96e5c0..8f4a63ea912e 100644
> --- a/arch/arm/boot/dts/imx53-ppd.dts
> +++ b/arch/arm/boot/dts/imx53-ppd.dts
> @@ -589,7 +589,7 @@ &i2c2 {
>  
>  	touchscreen@4b {
>  		compatible = "atmel,maxtouch";
> -		reset-gpio = <&gpio5 19 GPIO_ACTIVE_HIGH>;
> +		reset-gpio = <&gpio5 19 GPIO_ACTIVE_LOW>;
>  		reg = <0x4b>;
>  		interrupt-parent = <&gpio5>;
>  		interrupts = <4 IRQ_TYPE_LEVEL_LOW>;
> diff --git a/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts
> b/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts
> index 65359aece950..7da74e6f46d9 100644
> --- a/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts
> +++ b/arch/arm/boot/dts/imx6dl-colibri-eval-v3.dts
> @@ -143,7 +143,7 @@ touchscreen@4a {
>  		reg = <0x4a>;
>  		interrupt-parent = <&gpio1>;
>  		interrupts = <9 IRQ_TYPE_EDGE_FALLING>;		/*
> SODIMM 28 */
> -		reset-gpios = <&gpio2 10 GPIO_ACTIVE_HIGH>;	/*
> SODIMM 30 */
> +		reset-gpios = <&gpio2 10 GPIO_ACTIVE_LOW>;	/*
> SODIMM 30 */
>  		status = "disabled";
>  	};
>  
> diff --git a/arch/arm/boot/dts/imx6q-apalis-eval.dts
> b/arch/arm/boot/dts/imx6q-apalis-eval.dts
> index fab83abb6466..a0683b4aeca1 100644
> --- a/arch/arm/boot/dts/imx6q-apalis-eval.dts
> +++ b/arch/arm/boot/dts/imx6q-apalis-eval.dts
> @@ -140,7 +140,7 @@ touchscreen@4a {
>  		reg = <0x4a>;
>  		interrupt-parent = <&gpio6>;
>  		interrupts = <10 IRQ_TYPE_EDGE_FALLING>;
> -		reset-gpios = <&gpio6 9 GPIO_ACTIVE_HIGH>; /* SODIMM 13
> */
> +		reset-gpios = <&gpio6 9 GPIO_ACTIVE_LOW>; /* SODIMM 13
> */
>  		status = "disabled";
>  	};
>  
> diff --git a/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts
> b/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts
> index 1614b1ae501d..86e84781cf5d 100644
> --- a/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts
> +++ b/arch/arm/boot/dts/imx6q-apalis-ixora-v1.1.dts
> @@ -145,7 +145,7 @@ touchscreen@4a {
>  		reg = <0x4a>;
>  		interrupt-parent = <&gpio6>;
>  		interrupts = <10 IRQ_TYPE_EDGE_FALLING>;
> -		reset-gpios = <&gpio6 9 GPIO_ACTIVE_HIGH>; /* SODIMM 13
> */
> +		reset-gpios = <&gpio6 9 GPIO_ACTIVE_LOW>; /* SODIMM 13
> */
>  		status = "disabled";
>  	};
>  
> diff --git a/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> index fa9f98dd15ac..62e72773e53b 100644
> --- a/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> +++ b/arch/arm/boot/dts/imx6q-apalis-ixora.dts
> @@ -144,7 +144,7 @@ touchscreen@4a {
>  		reg = <0x4a>;
>  		interrupt-parent = <&gpio6>;
>  		interrupts = <10 IRQ_TYPE_EDGE_FALLING>;
> -		reset-gpios = <&gpio6 9 GPIO_ACTIVE_HIGH>; /* SODIMM 13
> */
> +		reset-gpios = <&gpio6 9 GPIO_ACTIVE_LOW>; /* SODIMM 13
> */
>  		status = "disabled";
>  	};
>  
> diff --git a/arch/arm/boot/dts/imx7-colibri-aster.dtsi
> b/arch/arm/boot/dts/imx7-colibri-aster.dtsi
> index 9fa701bec2ec..139188eb9f40 100644
> --- a/arch/arm/boot/dts/imx7-colibri-aster.dtsi
> +++ b/arch/arm/boot/dts/imx7-colibri-aster.dtsi
> @@ -99,7 +99,7 @@ touchscreen@4a {
>  		reg = <0x4a>;
>  		interrupt-parent = <&gpio2>;
>  		interrupts = <15 IRQ_TYPE_EDGE_FALLING>;	/* SODIMM 107
> */
> -		reset-gpios = <&gpio2 28 GPIO_ACTIVE_HIGH>;	/*
> SODIMM 106 */
> +		reset-gpios = <&gpio2 28 GPIO_ACTIVE_LOW>;	/*
> SODIMM 106 */
>  	};
>  
>  	/* M41T0M6 real time clock on carrier board */
> diff --git a/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
> b/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
> index 97601375f264..3caf450735d7 100644
> --- a/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
> +++ b/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
> @@ -124,7 +124,7 @@ touchscreen@4a {
>  		reg = <0x4a>;
>  		interrupt-parent = <&gpio1>;
>  		interrupts = <9 IRQ_TYPE_EDGE_FALLING>;		/*
> SODIMM 28 */
> -		reset-gpios = <&gpio1 10 GPIO_ACTIVE_HIGH>;	/*
> SODIMM 30 */
> +		reset-gpios = <&gpio1 10 GPIO_ACTIVE_LOW>;	/*
> SODIMM 30 */
>  		status = "disabled";
>  	};
>  
> diff --git a/arch/arm/boot/dts/motorola-mapphone-common.dtsi
> b/arch/arm/boot/dts/motorola-mapphone-common.dtsi
> index d5ded4f794df..5f8f77cfbe59 100644
> --- a/arch/arm/boot/dts/motorola-mapphone-common.dtsi
> +++ b/arch/arm/boot/dts/motorola-mapphone-common.dtsi
> @@ -430,7 +430,7 @@ touchscreen@4a {
>  		pinctrl-names = "default";
>  		pinctrl-0 = <&touchscreen_pins>;
>  
> -		reset-gpios = <&gpio6 13 GPIO_ACTIVE_HIGH>; /* gpio173
> */
> +		reset-gpios = <&gpio6 13 GPIO_ACTIVE_LOW>; /* gpio173 */
>  
>  		/* gpio_183 with sys_nirq2 pad as wakeup */
>  		interrupts-extended = <&gpio6 23 IRQ_TYPE_LEVEL_LOW>,
> diff --git a/arch/arm/boot/dts/s5pv210-aries.dtsi
> b/arch/arm/boot/dts/s5pv210-aries.dtsi
> index bd4450dbdcb6..4da33d0f2748 100644
> --- a/arch/arm/boot/dts/s5pv210-aries.dtsi
> +++ b/arch/arm/boot/dts/s5pv210-aries.dtsi
> @@ -632,7 +632,7 @@ touchscreen@4a {
>  		interrupts = <5 IRQ_TYPE_EDGE_FALLING>;
>  		pinctrl-names = "default";
>  		pinctrl-0 = <&ts_irq>;
> -		reset-gpios = <&gpj1 3 GPIO_ACTIVE_HIGH>;
> +		reset-gpios = <&gpj1 3 GPIO_ACTIVE_LOW>;
>  	};
>  };
>  
> diff --git a/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts
> b/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts
> index a0b829738e8f..10794a870776 100644
> --- a/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts
> +++ b/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts
> @@ -446,7 +446,7 @@ touchscreen@4c {
>  			interrupt-parent = <&gpio>;
>  			interrupts = <TEGRA_GPIO(V, 6)
> IRQ_TYPE_LEVEL_LOW>;
>  
> -			reset-gpios = <&gpio TEGRA_GPIO(Q, 7)
> GPIO_ACTIVE_HIGH>;
> +			reset-gpios = <&gpio TEGRA_GPIO(Q, 7)
> GPIO_ACTIVE_LOW>;
>  
>  			avdd-supply = <&vdd_3v3_sys>;
>  			vdd-supply  = <&vdd_3v3_sys>;
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c
> b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 98f17fa3a892..ef7915400c9f 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -3134,8 +3134,9 @@ static int mxt_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
>  	if (error)
>  		return error;
>  
> +	/* Request the RESET line as asserted so we go into reset */
>  	data->reset_gpio = devm_gpiod_get_optional(&client->dev,
> -						   "reset",
> GPIOD_OUT_LOW);
> +						   "reset",
> GPIOD_OUT_HIGH);
>  	if (IS_ERR(data->reset_gpio)) {
>  		error = PTR_ERR(data->reset_gpio);
>  		dev_err(&client->dev, "Failed to get reset gpio: %d\n",
> error);
> @@ -3153,8 +3154,9 @@ static int mxt_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
>  	disable_irq(client->irq);
>  
>  	if (data->reset_gpio) {
> +		/* Wait a while and then de-assert the RESET GPIO line
> */
>  		msleep(MXT_RESET_GPIO_TIME);
> -		gpiod_set_value(data->reset_gpio, 1);
> +		gpiod_set_value(data->reset_gpio, 0);
>  		msleep(MXT_RESET_INVALID_CHG);
>  	}
>  
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^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler
  2020-11-04 15:30 [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler Linus Walleij
  2020-11-04 15:59 ` Philippe Schenker
@ 2020-11-05  8:09 ` Krzysztof Kozlowski
  2020-11-23  6:48 ` Dmitry Torokhov
  2 siblings, 0 replies; 4+ messages in thread
From: Krzysztof Kozlowski @ 2020-11-05  8:09 UTC (permalink / raw)
  To: Linus Walleij
  Cc: linux-samsung-soc, Dmitry Torokhov, NXP Linux Team,
	Pengutronix Kernel Team, linux-input, linux-tegra,
	linux-arm-kernel

On Wed, Nov 04, 2020 at 04:30:30PM +0100, Linus Walleij wrote:
> This driver uses GPIO descriptors to drive the touchscreen
> RESET line. In the existing device trees this has in
> conflict with intution been flagged as GPIO_ACTIVE_HIGH
> and the driver then applies the reverse action by
> driving the line low (setting to 0) to enter
> reset state and driving the line high (setting to 1) to
> get out of reset state.
> 
> The correct way to handle active low GPIO lines is to
> provide the GPIO_ACTIVE_LOW in the device tree (thus
> properly describing the hardware) and letting the GPIO
> framework invert the assertion (driving high) to a low
> level and vice versa.
> 
> This is considered a bug since the device trees are
> incorrectly mis-specifying the line as active high.
> 
> Fix the driver and all device trees specifying a reset
> line.
> 
> Cc: Krzysztof Kozlowski <krzk@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-tegra@vger.kernel.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: NXP Linux Team <linux-imx@nxp.com>
> Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - New patch fixing this confusion before adding the
>   new YAML bindings.
> - CC some misc maintainers and mailing lists that should
>   be aware that we do this change.

Acked-by: Krzysztof Kozlowski <krzk@kernel.org>

Best regards,
Krzysztof

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^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler
  2020-11-04 15:30 [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler Linus Walleij
  2020-11-04 15:59 ` Philippe Schenker
  2020-11-05  8:09 ` Krzysztof Kozlowski
@ 2020-11-23  6:48 ` Dmitry Torokhov
  2 siblings, 0 replies; 4+ messages in thread
From: Dmitry Torokhov @ 2020-11-23  6:48 UTC (permalink / raw)
  To: Linus Walleij
  Cc: linux-samsung-soc, Krzysztof Kozlowski, NXP Linux Team,
	Pengutronix Kernel Team, linux-input, linux-tegra,
	linux-arm-kernel

On Wed, Nov 04, 2020 at 04:30:30PM +0100, Linus Walleij wrote:
> This driver uses GPIO descriptors to drive the touchscreen
> RESET line. In the existing device trees this has in
> conflict with intution been flagged as GPIO_ACTIVE_HIGH
> and the driver then applies the reverse action by
> driving the line low (setting to 0) to enter
> reset state and driving the line high (setting to 1) to
> get out of reset state.
> 
> The correct way to handle active low GPIO lines is to
> provide the GPIO_ACTIVE_LOW in the device tree (thus
> properly describing the hardware) and letting the GPIO
> framework invert the assertion (driving high) to a low
> level and vice versa.
> 
> This is considered a bug since the device trees are
> incorrectly mis-specifying the line as active high.
> 
> Fix the driver and all device trees specifying a reset
> line.
> 
> Cc: Krzysztof Kozlowski <krzk@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-tegra@vger.kernel.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: NXP Linux Team <linux-imx@nxp.com>
> Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Applied, thank you.

-- 
Dmitry

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^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-11-23  6:49 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-04 15:30 [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler Linus Walleij
2020-11-04 15:59 ` Philippe Schenker
2020-11-05  8:09 ` Krzysztof Kozlowski
2020-11-23  6:48 ` Dmitry Torokhov

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