[V3,3/4] pwm: tegra: Add DT binding details to configure pin in suspends/resume

Submitted by Laxman Dewangan on April 7, 2017, 9:34 a.m.

Details

Message ID 1491557642-15940-4-git-send-email-ldewangan@nvidia.com
State New
Headers show

Commit Message

Laxman Dewangan April 7, 2017, 9:34 a.m.
In some of NVIDIA Tegra's platform, PWM controller is used to
control the PWM controlled regulators. PWM signal is connected to
the VID pin of the regulator where duty cycle of PWM signal decide
the voltage level of the regulator output.

When system enters suspend, some PWM client/slave regulator devices
require the PWM output to be tristated.

Add DT binding details to provide the pin configuration state
from PWM and pinctrl DT node in suspend and active state of
the system.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>

---
Changes from v1:
- Use standard pinctrl names for sleep and active state.

Changes from V2:
- Fix the commit message and details
---
 .../devicetree/bindings/pwm/nvidia,tegra20-pwm.txt | 45 ++++++++++++++++++++++
 1 file changed, 45 insertions(+)

Comments

Jon Hunter April 7, 2017, 10:25 a.m.
On 07/04/17 10:34, Laxman Dewangan wrote:
> In some of NVIDIA Tegra's platform, PWM controller is used to
> control the PWM controlled regulators. PWM signal is connected to
> the VID pin of the regulator where duty cycle of PWM signal decide
> the voltage level of the regulator output.
> 
> When system enters suspend, some PWM client/slave regulator devices
> require the PWM output to be tristated.
> 
> Add DT binding details to provide the pin configuration state
> from PWM and pinctrl DT node in suspend and active state of
> the system.
> 
> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
> 
> ---
> Changes from v1:
> - Use standard pinctrl names for sleep and active state.
> 
> Changes from V2:
> - Fix the commit message and details
> ---
>  .../devicetree/bindings/pwm/nvidia,tegra20-pwm.txt | 45 ++++++++++++++++++++++
>  1 file changed, 45 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
> index b4e7377..c57e11b 100644
> --- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
> +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
> @@ -19,6 +19,19 @@ Required properties:
>  - reset-names: Must include the following entries:
>    - pwm
>  
> +Optional properties:
> +============================
> +In some of the interface like PWM based regulator device, it is required
> +to configure the pins differently in different states, especially in suspend
> +state of the system. The configuration of pin is provided via the pinctrl
> +DT node as detailed in the pinctrl DT binding document
> +	Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> +
> +The PWM node will have following optional properties.
> +pinctrl-names:	Pin state names. Must be "default" and "sleep".
> +pinctrl-0:	phandle for the default/active state of pin configurations.
> +pinctrl-1:	phandle for the sleep state of pin configurations.
> +
>  Example:
>  
>  	pwm: pwm@7000a000 {
> @@ -29,3 +42,35 @@ Example:
>  		resets = <&tegra_car 17>;
>  		reset-names = "pwm";
>  	};
> +
> +
> +Example with the pin configuration for suspend and resume:
> +=========================================================
> +Suppose pin PE7 (On Tegra210) interfaced with the regulator device and
> +it requires PWM output to be tristated when system enters suspend.
> +Following will be DT binding to achieve this:
> +
> +#include <dt-bindings/pinctrl/pinctrl-tegra.h>
> +
> +	pinmux@700008d4 {
> +		pwm_active_state: pwm_active_state {
> +                        pe7 {
> +                                nvidia,pins = "pe7";
> +                                nvidia,tristate = <TEGRA_PIN_DISABLE>;
> +			};
> +		};
> +
> +		pwm_sleep_state: pwm_sleep_state {
> +                        pe7 {
> +                                nvidia,pins = "pe7";
> +                                nvidia,tristate = <TEGRA_PIN_ENABLE>;
> +			};
> +		};
> +	};
> +
> +	pwm@7000a000 {
> +		/* Mandatory PWM properties */

Maybe these are mandatory for the platform, but given these are
optional, its a bit confusing.

> +		pinctrl-names = "default", "sleep";
> +		pinctrl-0 = <&pwm_active_state>;
> +		pinctrl-1 = <&pwm_sleep_state>;
> +	};

However, fine with me so ...

Acked-by: Jon Hunter <jonathanh@nvidia.com>

Cheers
Jon
Rob Herring April 10, 2017, 8:13 p.m.
On Fri, Apr 07, 2017 at 03:04:01PM +0530, Laxman Dewangan wrote:
> In some of NVIDIA Tegra's platform, PWM controller is used to
> control the PWM controlled regulators. PWM signal is connected to
> the VID pin of the regulator where duty cycle of PWM signal decide
> the voltage level of the regulator output.
> 
> When system enters suspend, some PWM client/slave regulator devices
> require the PWM output to be tristated.
> 
> Add DT binding details to provide the pin configuration state
> from PWM and pinctrl DT node in suspend and active state of
> the system.
> 
> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
> 
> ---
> Changes from v1:
> - Use standard pinctrl names for sleep and active state.
> 
> Changes from V2:
> - Fix the commit message and details
> ---
>  .../devicetree/bindings/pwm/nvidia,tegra20-pwm.txt | 45 ++++++++++++++++++++++
>  1 file changed, 45 insertions(+)

Acked-by: Rob Herring <robh@kernel.org> 
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diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
index b4e7377..c57e11b 100644
--- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
+++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
@@ -19,6 +19,19 @@  Required properties:
 - reset-names: Must include the following entries:
   - pwm
 
+Optional properties:
+============================
+In some of the interface like PWM based regulator device, it is required
+to configure the pins differently in different states, especially in suspend
+state of the system. The configuration of pin is provided via the pinctrl
+DT node as detailed in the pinctrl DT binding document
+	Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+
+The PWM node will have following optional properties.
+pinctrl-names:	Pin state names. Must be "default" and "sleep".
+pinctrl-0:	phandle for the default/active state of pin configurations.
+pinctrl-1:	phandle for the sleep state of pin configurations.
+
 Example:
 
 	pwm: pwm@7000a000 {
@@ -29,3 +42,35 @@  Example:
 		resets = <&tegra_car 17>;
 		reset-names = "pwm";
 	};
+
+
+Example with the pin configuration for suspend and resume:
+=========================================================
+Suppose pin PE7 (On Tegra210) interfaced with the regulator device and
+it requires PWM output to be tristated when system enters suspend.
+Following will be DT binding to achieve this:
+
+#include <dt-bindings/pinctrl/pinctrl-tegra.h>
+
+	pinmux@700008d4 {
+		pwm_active_state: pwm_active_state {
+                        pe7 {
+                                nvidia,pins = "pe7";
+                                nvidia,tristate = <TEGRA_PIN_DISABLE>;
+			};
+		};
+
+		pwm_sleep_state: pwm_sleep_state {
+                        pe7 {
+                                nvidia,pins = "pe7";
+                                nvidia,tristate = <TEGRA_PIN_ENABLE>;
+			};
+		};
+	};
+
+	pwm@7000a000 {
+		/* Mandatory PWM properties */
+		pinctrl-names = "default", "sleep";
+		pinctrl-0 = <&pwm_active_state>;
+		pinctrl-1 = <&pwm_sleep_state>;
+	};