linux-kernel - Re: [PATCH v7 1/3] pwm: Introduce single-PWM of

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Date:   Tue, 26 Oct 2021 12:21:50 -0500
From:   Steev Klimaszewski <steev@...i.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
        Lee Jones <lee.jones@...aro.org>,
        Robert Foss <robert.foss@...aro.org>
Cc:     linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v7 1/3] pwm: Introduce single-PWM of_xlate function


On 10/25/21 12:09 PM, Bjorn Andersson wrote:
> The existing pxa driver and the upcoming addition of PWM support in the
> TI sn565dsi86 DSI/eDP bridge driver both has a single PWM channel and
> thereby a need for a of_xlate function with the period as its single
> argument.
>
> Introduce a common helper function in the core that can be used as
> of_xlate by such drivers and migrate the pxa driver to use this.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> Acked-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
> Tested-by: Steev Klimaszewski <steev@...i.org>
> ---
>
> Changes since v6:
> - None
>
>   drivers/pwm/core.c    | 26 ++++++++++++++++++++++++++
>   drivers/pwm/pwm-pxa.c | 16 +---------------
>   include/linux/pwm.h   |  2 ++
>   3 files changed, 29 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index 4527f09a5c50..2c6b155002a2 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -152,6 +152,32 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
>   }
>   EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
>   
> +struct pwm_device *
> +of_pwm_single_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
> +{
> +	struct pwm_device *pwm;
> +
> +	if (pc->of_pwm_n_cells < 1)
> +		return ERR_PTR(-EINVAL);
> +
> +	/* validate that one cell is specified, optionally with flags */
> +	if (args->args_count != 1 && args->args_count != 2)
> +		return ERR_PTR(-EINVAL);
> +
> +	pwm = pwm_request_from_chip(pc, 0, NULL);
> +	if (IS_ERR(pwm))
> +		return pwm;
> +
> +	pwm->args.period = args->args[0];
> +	pwm->args.polarity = PWM_POLARITY_NORMAL;
> +
> +	if (args->args_count == 2 && args->args[2] & PWM_POLARITY_INVERTED)
> +		pwm->args.polarity = PWM_POLARITY_INVERSED;
> +
> +	return pwm;
> +}
> +EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
> +
>   static void of_pwmchip_add(struct pwm_chip *chip)
>   {
>   	if (!chip->dev || !chip->dev->of_node)
> diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
> index a9efdcf839ae..238ec88c130b 100644
> --- a/drivers/pwm/pwm-pxa.c
> +++ b/drivers/pwm/pwm-pxa.c
> @@ -148,20 +148,6 @@ static const struct platform_device_id *pxa_pwm_get_id_dt(struct device *dev)
>   	return id ? id->data : NULL;
>   }
>   
> -static struct pwm_device *
> -pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
> -{
> -	struct pwm_device *pwm;
> -
> -	pwm = pwm_request_from_chip(pc, 0, NULL);
> -	if (IS_ERR(pwm))
> -		return pwm;
> -
> -	pwm->args.period = args->args[0];
> -
> -	return pwm;
> -}
> -
>   static int pwm_probe(struct platform_device *pdev)
>   {
>   	const struct platform_device_id *id = platform_get_device_id(pdev);
> @@ -187,7 +173,7 @@ static int pwm_probe(struct platform_device *pdev)
>   	pc->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
>   
>   	if (IS_ENABLED(CONFIG_OF)) {
> -		pc->chip.of_xlate = pxa_pwm_of_xlate;
> +		pc->chip.of_xlate = of_pwm_single_xlate;
>   		pc->chip.of_pwm_n_cells = 1;
>   	}
>   
> diff --git a/include/linux/pwm.h b/include/linux/pwm.h
> index 725c9b784e60..dd51d4931fdc 100644
> --- a/include/linux/pwm.h
> +++ b/include/linux/pwm.h
> @@ -414,6 +414,8 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
>   
>   struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
>   		const struct of_phandle_args *args);
> +struct pwm_device *of_pwm_single_xlate(struct pwm_chip *pc,
> +				       const struct of_phandle_args *args);
>   
>   struct pwm_device *pwm_get(struct device *dev, const char *con_id);
>   struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,

v7 of the series is tested by me on the Lenovo Yoga C630

Tested-By: Steev Klimaszewski <steev@...i.org>