linux-fbdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Daniel Thompson <daniel.thompson@linaro.org>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Lee Jones <lee.jones@linaro.org>,
	Jingoo Han <jingoohan1@gmail.com>,
	linux-fbdev@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	kernel@pengutronix.de, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 2/2] backlight: lm3630a: convert to atomic PWM API and check for errors
Date: Mon, 21 Jun 2021 11:47:40 +0100	[thread overview]
Message-ID: <20210621104740.cenlzw2wfy2vacoi@maple.lan> (raw)
In-Reply-To: <20210620193928.14467-2-u.kleine-koenig@pengutronix.de>

On Sun, Jun 20, 2021 at 09:39:28PM +0200, Uwe Kleine-König wrote:
> The practical upside here is that this only needs a single API call to
> program the hardware which (depending on the underlaying hardware) can
> be more effective and prevents glitches.
> 
> Up to now the return value of the pwm functions was ignored. Fix this
> and propagate the error to the caller.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/video/backlight/lm3630a_bl.c | 34 +++++++++++++---------------
>  1 file changed, 16 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> index 16a2658a72e1..99eb8277149b 100644
> --- a/drivers/video/backlight/lm3630a_bl.c
> +++ b/drivers/video/backlight/lm3630a_bl.c
> @@ -52,6 +52,7 @@ struct lm3630a_chip {
>  	struct gpio_desc *enable_gpio;
>  	struct regmap *regmap;
>  	struct pwm_device *pwmd;
> +	struct pwm_state pwmd_state;
>  };
>  
>  /* i2c access */
> @@ -167,16 +168,19 @@ static int lm3630a_intr_config(struct lm3630a_chip *pchip)
>  	return rval;
>  }
>  
> -static void lm3630a_pwm_ctrl(struct lm3630a_chip *pchip, int br, int br_max)
> +static int lm3630a_pwm_ctrl(struct lm3630a_chip *pchip, int br, int br_max)
>  {
> -	unsigned int period = pchip->pdata->pwm_period;
> -	unsigned int duty = br * period / br_max;
> +	int err;
>  
> -	pwm_config(pchip->pwmd, duty, period);
> -	if (duty)
> -		pwm_enable(pchip->pwmd);
> -	else
> -		pwm_disable(pchip->pwmd);
> +	pchip->pwmd_state.period = pchip->pdata->pwm_period;
> +
> +	err = pwm_set_relative_duty_cycle(&pchip->pwmd_state, br, br_max);
> +	if (err)
> +		return err;
> +
> +	pchip->pwmd_state.enabled = pchip->pwmd_state.duty_cycle ? true : false;
> +
> +	return pwm_apply_state(pchip->pwmd, &pchip->pwmd_state);
>  }
>  
>  /* update and get brightness */
> @@ -187,11 +191,9 @@ static int lm3630a_bank_a_update_status(struct backlight_device *bl)
>  	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;
>  
>  	/* pwm control */
> -	if ((pwm_ctrl & LM3630A_PWM_BANK_A) != 0) {
> -		lm3630a_pwm_ctrl(pchip, bl->props.brightness,
> -				 bl->props.max_brightness);
> -		return 0;
> -	}
> +	if ((pwm_ctrl & LM3630A_PWM_BANK_A) != 0)
> +		return lm3630a_pwm_ctrl(pchip, bl->props.brightness,
> +					bl->props.max_brightness);

My apologies for overlooking this at v1 (and even when reviewing the first of
the v2 patchs) but...  this fixes the code for bank A. Bank B also requires exactly
the same set of fixes!


Daniel.

  reply	other threads:[~2021-06-21 10:47 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-20 19:39 [PATCH v2 1/2] backlight: lm3630a: fix return code of .update_status() callback Uwe Kleine-König
2021-06-20 19:39 ` [PATCH v2 2/2] backlight: lm3630a: convert to atomic PWM API and check for errors Uwe Kleine-König
2021-06-21 10:47   ` Daniel Thompson [this message]
2021-06-21 10:23 ` [PATCH v2 1/2] backlight: lm3630a: fix return code of .update_status() callback Daniel Thompson
2021-06-21 11:41   ` Daniel Thompson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210621104740.cenlzw2wfy2vacoi@maple.lan \
    --to=daniel.thompson@linaro.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=jingoohan1@gmail.com \
    --cc=kernel@pengutronix.de \
    --cc=lee.jones@linaro.org \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=thierry.reding@gmail.com \
    --cc=u.kleine-koenig@pengutronix.de \
    --subject='Re: [PATCH v2 2/2] backlight: lm3630a: convert to atomic PWM API and check for errors' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).