pwm: stm32: Implement .get_state()

Implement the &pwm_ops->get_state callback so drivers can inherit PWM
state set by the bootloader.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
[ukl: split off from a patch that also fixes clk enable count in .probe()]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index 0da371291cef85e002f8c1120753eebfd615618d..9a7d7891edde73ab38a863f13e5dfff18441e9d2 100644 (file)
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -471,8 +471,50 @@ static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm,
        return ret;
 }
 
+static int stm32_pwm_get_state(struct pwm_chip *chip,
+                              struct pwm_device *pwm, struct pwm_state *state)
+{
+       struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+       int ch = pwm->hwpwm;
+       unsigned long rate;
+       u32 ccer, psc, arr, ccr;
+       u64 dty, prd;
+       int ret;
+
+       mutex_lock(&priv->lock);
+
+       ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
+       if (ret)
+               goto out;
+
+       state->enabled = ccer & (TIM_CCER_CC1E << (ch * 4));
+       state->polarity = (ccer & (TIM_CCER_CC1P << (ch * 4))) ?
+                         PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
+       ret = regmap_read(priv->regmap, TIM_PSC, &psc);
+       if (ret)
+               goto out;
+       ret = regmap_read(priv->regmap, TIM_ARR, &arr);
+       if (ret)
+               goto out;
+       ret = regmap_read(priv->regmap, TIM_CCR1 + 4 * ch, &ccr);
+       if (ret)
+               goto out;
+
+       rate = clk_get_rate(priv->clk);
+
+       prd = (u64)NSEC_PER_SEC * (psc + 1) * (arr + 1);
+       state->period = DIV_ROUND_UP_ULL(prd, rate);
+       dty = (u64)NSEC_PER_SEC * (psc + 1) * ccr;
+       state->duty_cycle = DIV_ROUND_UP_ULL(dty, rate);
+
+out:
+       mutex_unlock(&priv->lock);
+       return ret;
+}
+
 static const struct pwm_ops stm32pwm_ops = {
        .apply = stm32_pwm_apply_locked,
+       .get_state = stm32_pwm_get_state,
        .capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL,
 };