Re: [PATCH v3] clk: Add PWM clock driver

From: Philipp Zabel
Date: Fri Dec 12 2014 - 04:54:17 EST

Hi Janusz,

Am Freitag, den 12.12.2014, 09:58 +0100 schrieb Janusz UÅycki:
> Hi Philipp,
> It moved .enable to .prepare which can sleep and it works
> without any bug.
> The dirty fix:
> const struct clk_ops clk_pwm_ops = {
> - .enable = clk_pwm_enable,
> - .disable = clk_pwm_disable,
> + .prepare = clk_pwm_enable,
> + .unprepare = clk_pwm_disable,
> .recalc_rate = clk_pwm_recalc_rate,
> };
> What do you think about?

Thanks! Since the pwm API does not give any guarantees that
pwm_enable/disable may be called from atomic context, I think this
change is correct. The PWM documentation says:

"Currently the PWM core does not enforce any locking to pwm_enable(),
pwm_disable() and pwm_config(), so the calling context is currently
driver specific. This is an issue derived from the former barebone
API and should be fixed soon."

clk_enable should support reentrancy, but calling clk_prepare_enable
inside a clk_enable callback is not going to work.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at