[PATCH 5/7] pwm: sifive: Simplify clk handling
Uwe Kleine-König
u.kleine-koenig at pengutronix.de
Thu Jul 21 03:31:27 PDT 2022
The clk is necessary for both register access and (enabled) operation of
the PWM. Instead of
clk_enable()
update_hw()
if pwm_got_enabled():
clk_enable()
elif pwm_got_disabled():
clk_disable()
clk_disable()
which is some cases only calls clk_enable() to immediately afterwards
call clk_disable again, do:
if (!prev_state.enabled)
clk_enable()
# clk enabled exactly once
update_hw()
if (!next_state.enabled)
clk_disable()
which is much easier.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
drivers/pwm/pwm-sifive.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index d833536b5e7a..34d23d56fa25 100644
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -168,24 +168,24 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
}
mutex_unlock(&ddata->lock);
- ret = clk_enable(ddata->clk);
- if (ret) {
- dev_err(ddata->chip.dev, "Enable clk failed\n");
- return ret;
+ /*
+ * If the PWM is enabled the clk is already on. So only enable it
+ * conditionally to have it on exactly once afterwards independent of
+ * the PWM state.
+ */
+ if (!enabled) {
+ 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) {
- if (state->enabled) {
- if (clk_enable(ddata->clk))
- dev_err(ddata->chip.dev, "Enable clk failed\n");
- } else {
- clk_disable(ddata->clk);
- }
- }
+ if (!state->enabled)
+ clk_disable(ddata->clk);
- clk_disable(ddata->clk);
return 0;
}
--
2.36.1
More information about the linux-riscv
mailing list