linux-kernel - Re: [PATCH V4 4/4] pwm: tegra: Add support to configure pin state in suspends/resume

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Message-ID: <e6eef15a-45e4-002b-dd45-38c268070241@nvidia.com>
Date:   Thu, 6 Apr 2017 16:17:34 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     Laxman Dewangan <ldewangan@...dia.com>, <thierry.reding@...il.com>,
        <robh+dt@...nel.org>
CC:     <mark.rutland@....com>, <linux-pwm@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V4 4/4] pwm: tegra: Add support to configure pin state in
 suspends/resume


On 06/04/17 15:21, 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.
> 
> The tristate (high impedance of PWM pin form Tegra) also define
> one of the state of PWM regulator which needs to be configure in
> suspend state of system.
> 
> Add support to configure the pin state via pinctrl frameworks in
> suspend and active state of the system.
> 
> Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>
> ---
> Changes from v1:
> - Use standard pinctrl names for sleep and active state.
> - Use API pinctrl_pm_select_*()
> 
>  drivers/pwm/pwm-tegra.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
> index e9c4de5..af1bd4f 100644
> --- a/drivers/pwm/pwm-tegra.c
> +++ b/drivers/pwm/pwm-tegra.c
> @@ -29,6 +29,7 @@
>  #include <linux/of_device.h>
>  #include <linux/pwm.h>
>  #include <linux/platform_device.h>
> +#include <linux/pinctrl/consumer.h>
>  #include <linux/slab.h>
>  #include <linux/reset.h>
>  
> @@ -256,6 +257,22 @@ static int tegra_pwm_remove(struct platform_device *pdev)
>  	return pwmchip_remove(&pc->chip);
>  }
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int tegra_pwm_suspend(struct device *dev)
> +{
> +	pinctrl_pm_select_sleep_state(dev);

Why not return the error code here?

> +
> +	return 0;
> +}
> +
> +static int tegra_pwm_resume(struct device *dev)
> +{
> +	pinctrl_pm_select_default_state(dev);

And here.

By the way, do you plan to include patches to populate the bindings for
the pwm devices?

Cheers
Jon

-- 
nvpublic