pwm: sifive: Enable clk only after period check in .apply()

For the period check and the initial calculations of register values there
is no hardware access needed. So delay enabling the clk a bit to simplify
the code flow a bit.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index 6017e31..d833536 100644 (file)
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -139,12 +139,6 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
        if (state->polarity != PWM_POLARITY_INVERSED)
                return -EINVAL;
 
-       ret = clk_enable(ddata->clk);
-       if (ret) {
-               dev_err(ddata->chip.dev, "Enable clk failed\n");
-               return ret;
-       }
-
        cur_state = pwm->state;
        enabled = cur_state.enabled;
 
@@ -167,14 +161,19 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
        if (state->period != ddata->approx_period) {
                if (ddata->user_count != 1) {
                        mutex_unlock(&ddata->lock);
-                       ret = -EBUSY;
-                       goto exit;
+                       return -EBUSY;
                }
                ddata->approx_period = state->period;
                pwm_sifive_update_clock(ddata, clk_get_rate(ddata->clk));
        }
        mutex_unlock(&ddata->lock);
 
+       ret = clk_enable(ddata->clk);
+       if (ret) {
+               dev_err(ddata->chip.dev, "Enable clk failed\n");
+               return ret;
+       }
+
        writel(frac, ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm));
 
        if (state->enabled != enabled) {
@@ -186,9 +185,8 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
                }
        }
 
-exit:
        clk_disable(ddata->clk);
-       return ret;
+       return 0;
 }
 
 static const struct pwm_ops pwm_sifive_ops = {