linux-kernel - Re: [PATCH] media: ir-rx51: Switch to atomic PWM API

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Message-ID: <20211029111232.soknq7mu3r65laar@pengutronix.de>
Date:   Fri, 29 Oct 2021 13:12:32 +0200
From:   Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To:     Maíra Canal <maira.canal@....br>
Cc:     sean@...s.org, mchehab@...nel.org, thierry.reding@...il.com,
        lee.jones@...aro.org, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
        kernel@...gutronix.de
Subject: Re: [PATCH] media: ir-rx51: Switch to atomic PWM API

Hello Maíra,

On Thu, Oct 28, 2021 at 11:12:47AM -0300, Maíra Canal wrote:
> Remove legacy PWM interface (pwm_config, pwm_enable, pwm_disable) and
> replace it for the atomic PWM API.
> 
> Signed-off-by: Maíra Canal <maira.canal@....br>
> ---
>  drivers/media/rc/ir-rx51.c | 27 +++++++++++++--------------
>  1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/media/rc/ir-rx51.c b/drivers/media/rc/ir-rx51.c
> index a0d9c02a7588..7a643a94e181 100644
> --- a/drivers/media/rc/ir-rx51.c
> +++ b/drivers/media/rc/ir-rx51.c
> @@ -19,6 +19,7 @@
>  struct ir_rx51 {
>  	struct rc_dev *rcdev;
>  	struct pwm_device *pwm;
> +	struct pwm_state *state;
>  	struct hrtimer timer;
>  	struct device	     *dev;
>  	wait_queue_head_t     wqueue;
> @@ -32,22 +33,22 @@ struct ir_rx51 {
>  
>  static inline void ir_rx51_on(struct ir_rx51 *ir_rx51)
>  {
> -	pwm_enable(ir_rx51->pwm);
> +	ir_rx51->state->enabled = true;
> +	pwm_apply_state(ir_rx51->pwm, ir_rx51->state);
>  }
>  
>  static inline void ir_rx51_off(struct ir_rx51 *ir_rx51)
>  {
> -	pwm_disable(ir_rx51->pwm);
> +	ir_rx51->state->enabled = false;
> +	pwm_apply_state(ir_rx51->pwm, ir_rx51->state);
>  }
>  
>  static int init_timing_params(struct ir_rx51 *ir_rx51)
>  {
> -	struct pwm_device *pwm = ir_rx51->pwm;
> -	int duty, period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq);
> +	struct pwm_state *state = ir_rx51->state;
>  
> -	duty = DIV_ROUND_CLOSEST(ir_rx51->duty_cycle * period, 100);
> -
> -	pwm_config(pwm, duty, period);
> +	state->period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq);
> +	pwm_set_relative_duty_cycle(state, ir_rx51->duty_cycle, 100);
>  
>  	return 0;
>  }
> @@ -154,6 +155,8 @@ static int ir_rx51_open(struct rc_dev *dev)
>  		return res;
>  	}
>  
> +	pwm_init_state(ir_rx51->pwm, ir_rx51->state);
> +

Doing this here introduces a change in behaviour. Better do this after
pwm_get().

>  	return 0;
>  }
>  
> @@ -232,13 +235,9 @@ static int ir_rx51_probe(struct platform_device *dev)
>  	struct rc_dev *rcdev;
>  
>  	pwm = pwm_get(&dev->dev, NULL);
> -	if (IS_ERR(pwm)) {
> -		int err = PTR_ERR(pwm);
> -
> -		if (err != -EPROBE_DEFER)
> -			dev_err(&dev->dev, "pwm_get failed: %d\n", err);
> -		return err;
> -	}
> +	if (IS_ERR(pwm))
> +		return dev_err_probe(&dev->dev, PTR_ERR(pwm), "pwm_get failed: %ld\n",
> +				PTR_ERR(pwm));
>  
>  	/* Use default, in case userspace does not set the carrier */
>  	ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm), NSEC_PER_SEC);

Conceptually this last hunk belongs in a separate patch. And you don't
need to repeat PTR_ERR(pwm), as dev_err_probe already emits this
information. So

	return dev_err_probe(&dev->dev, PTR_ERR(pwm), "pwm_get failed\n");

should be fine.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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