diff mbox series

[v2,2/2] backlight: lm3630a: convert to atomic PWM API and check for errors

Message ID 20210620193928.14467-2-u.kleine-koenig@pengutronix.de
State New
Headers show
Series [v2,1/2] backlight: lm3630a: fix return code of .update_status() callback | expand

Commit Message

Uwe Kleine-König June 20, 2021, 7:39 p.m. UTC
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(-)

Comments

Daniel Thompson June 21, 2021, 10:47 a.m. UTC | #1
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.
diff mbox series

Patch

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);
 
 	/* disable sleep */
 	ret = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
@@ -563,11 +565,7 @@  static int lm3630a_probe(struct i2c_client *client,
 			return PTR_ERR(pchip->pwmd);
 		}
 
-		/*
-		 * FIXME: pwm_apply_args() should be removed when switching to
-		 * the atomic PWM API.
-		 */
-		pwm_apply_args(pchip->pwmd);
+		pwm_init_state(pchip->pwmd, &pchip->pwmd_state);
 	}
 
 	/* interrupt enable  : irq 0 is not allowed */