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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Ahmad Fatoum <ahmad@a3f.at>
Cc: barebox@lists.infradead.org, Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: Re: [PATCH 08/12] video: backlight-pwm: use new pwm_apply_state API
Date: Tue, 31 Mar 2020 08:10:06 +0200	[thread overview]
Message-ID: <20200331061006.GG27288@pengutronix.de> (raw)
In-Reply-To: <20200330145717.667403-9-ahmad@a3f.at>

On Mon, Mar 30, 2020 at 04:57:13PM +0200, Ahmad Fatoum wrote:
> From: Ahmad Fatoum <a.fatoum@pengutronix.de>
> 
> Use pwm_apply_state we can avoid having to store PWM state in the
> instance structure and in future we have an easy way to support new
> parameters like inverted duty cycle.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/video/backlight-pwm.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/video/backlight-pwm.c b/drivers/video/backlight-pwm.c
> index 9111a42d7544..8b6494dac929 100644
> --- a/drivers/video/backlight-pwm.c
> +++ b/drivers/video/backlight-pwm.c
> @@ -33,7 +33,6 @@ struct pwm_backlight {
>  	struct backlight_device backlight;
>  	struct pwm_device *pwm;
>  	struct regulator *power;
> -	uint32_t period;
>  	unsigned int *levels;
>  	int enable_gpio;
>  	int enable_active_high;
> @@ -91,13 +90,16 @@ static int backlight_pwm_disable(struct pwm_backlight *pwm_backlight)
>  static int compute_duty_cycle(struct pwm_backlight *pwm_backlight, int brightness)
>  {
>  	int duty_cycle;
> +	struct pwm_state state;
> +
> +	pwm_get_state(pwm_backlight->pwm, &state);
>  
>  	if (pwm_backlight->levels)
>  		duty_cycle = pwm_backlight->levels[brightness];
>  	else
>  		duty_cycle = brightness;
>  
> -	return duty_cycle * pwm_backlight->period / pwm_backlight->scale;
> +	return duty_cycle * state.period_ns / pwm_backlight->scale;
>  }
>  
>  static int backlight_pwm_set(struct backlight_device *backlight,
> @@ -105,9 +107,11 @@ static int backlight_pwm_set(struct backlight_device *backlight,
>  {
>  	struct pwm_backlight *pwm_backlight = container_of(backlight,
>  			struct pwm_backlight, backlight);
> +	struct pwm_state state;
>  
> -	pwm_config(pwm_backlight->pwm, compute_duty_cycle(pwm_backlight, brightness),
> -		   pwm_backlight->period);
> +	pwm_get_state(pwm_backlight->pwm, &state);

You read the current pwm state here...

> +	state.duty_ns = compute_duty_cycle(pwm_backlight, brightness);

and once again in compute_duty_cycle(). I think it would be nicer to
reorganize this a bit, maybe pass the state to compute_duty_cycle.

> +	pwm_apply_state(pwm_backlight->pwm, &state);
>  
>  	if (brightness)
>  		return backlight_pwm_enable(pwm_backlight);

I would assume that if you switch to the pwm_apply_state API then you do
it entirely. backlight_pwm_enable() still uses the old API to enable the
PWM.

Sascha

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  reply	other threads:[~2020-03-31  6:10 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-30 14:57 [PATCH 00/12] PWM: add support for ->apply, polarity and STM32 Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 01/12] led: pwm: always initialize PWM LEDs as inactive Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 02/12] PWM: core: remove FLAG_ENABLED Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 03/12] PWM: core: remove ineffectual pwm_{set,get}_duty_cycle Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 04/12] PWM: core: group PWM state into new struct pwm_state Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 05/12] PWM: core: remove old PWM API in favor of Linux ->apply Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 06/12] PWM: core: retire pwm_set_period Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 07/12] PWM: core: apply initial state in of_pwm_request Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 08/12] video: backlight-pwm: use new pwm_apply_state API Ahmad Fatoum
2020-03-31  6:10   ` Sascha Hauer [this message]
2020-03-31  6:54     ` Ahmad Fatoum
2020-03-31  7:49       ` Sascha Hauer
2020-03-30 14:57 ` [PATCH 09/12] led: pwm: " Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 10/12] PWM: core: add apply API support for polarity Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 11/12] of: introduce of_property_count_elems_of_size Ahmad Fatoum
2020-03-30 14:57 ` [PATCH 12/12] PWM: add support for STM32 Ahmad Fatoum
2020-03-31  6:41   ` Sascha Hauer
2020-03-31  6:49     ` Ahmad Fatoum
2020-03-31  7:49       ` Sascha Hauer

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