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pwm: sifive: Simplify clk handling 

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@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Uwe Kleine-König 2022-07-21 12:31:27 +02:00 committed by Thierry Reding
parent 3586b02663
commit 1695b421e1
1 changed files with 13 additions and 13 deletions
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26
drivers/pwm/pwm-sifive.c
View File

@ -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;
}