[v6,1/3] pwm: Introduce single-PWM of_xlate function

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@linaro.org>
---

Changes since v4:
- None

 drivers/pwm/core.c    | 26 ++++++++++++++++++++++++++
 drivers/pwm/pwm-pxa.c | 16 +---------------
 include/linux/pwm.h   |  2 ++
 3 files changed, 29 insertions(+), 15 deletions(-)

On 9/29/21 10:05 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@linaro.org>
> ---
>
> Changes since v4:
> - 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,


I've tested these v6 all 3 patches on the Lenovo Yoga C630

Tested-by: Steev Klimaszewski <steev@kali.org>

On Wed, Sep 29, 2021 at 10:05:55PM -0500, 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@linaro.org>

I'm OK with this patch, in the long run I'd like to share more code with
of_pwm_xlate_with_flags, but this shouldn't be a stopper here.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Best regards
Uwe