backlight: lm3630a: Convert to atomic PWM API and check for errors

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>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
index 419b0334cf0879b71aa180d59f3af8b94f934fb6..e8b185bb6f5ee1cfccbd6c8ef5344a086a5e6459 100644 (file)
--- 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);
@@ -264,11 +266,9 @@ static int lm3630a_bank_b_update_status(struct backlight_device *bl)
        enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;
 
        /* pwm control */
-       if ((pwm_ctrl & LM3630A_PWM_BANK_B) != 0) {
-               lm3630a_pwm_ctrl(pchip, bl->props.brightness,
-                                bl->props.max_brightness);
-               return 0;
-       }
+       if ((pwm_ctrl & LM3630A_PWM_BANK_B) != 0)
+               return lm3630a_pwm_ctrl(pchip, bl->props.brightness,
+                                       bl->props.max_brightness);
 
        /* disable sleep */
        ret = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
@@ -565,11 +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 */