Commit 1695b421 authored Jul 21, 2022 by Uwe Kleine-König Committed by Thierry Reding Jul 29, 2022

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>

parent 3586b026

drivers/pwm/pwm-sifive.c

+13 −13

Original line number	Diff line number	Diff line
		@@ -168,24 +168,24 @@ static int pwm_sifive_apply(struct pwm_chip chip, struct pwm_device pwm,
		}
		mutex_unlock(&ddata->lock);

		/*
		* 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 {
		if (!state->enabled)
		clk_disable(ddata->clk);
		}
		}

		clk_disable(ddata->clk);
		return 0;
		}