On Mon, Mar 29, 2021 at 02:57:03PM +0200, Clemens Gruber wrote: > The chip does not come out of POR in active state but in sleep state. > To be sure (in case the bootloader woke it up) we force it to sleep in > probe. > > On kernels without CONFIG_PM, we wake the chip in .probe and put it to > sleep in .remove.
What is the effect of sleep state? Does it continue to oscilate it the
bootloader set up some configuration?
> Signed-off-by: Clemens Gruber <clemens.gru...@pqgruber.com>
> ---
> drivers/pwm/pwm-pca9685.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c
> index fb026a25fb61..4d6684b90819 100644
> --- a/drivers/pwm/pwm-pca9685.c
> +++ b/drivers/pwm/pwm-pca9685.c
> @@ -469,14 +469,19 @@ static int pca9685_pwm_probe(struct i2c_client *client,
> return ret;
> }
>
> - /* The chip comes out of power-up in the active state */
> - pm_runtime_set_active(&client->dev);
> /*
> - * Enable will put the chip into suspend, which is what we
> - * want as all outputs are disabled at this point
> + * The chip comes out of power-up in the sleep state,
> + * but force it to sleep in case it was woken up before
> */
> + pca9685_set_sleep_mode(pca, true);
> + pm_runtime_set_suspended(&client->dev);
> pm_runtime_enable(&client->dev);
>
> + if (!IS_ENABLED(CONFIG_PM)) {
> + /* Wake the chip up on non-PM environments */
> + pca9685_set_sleep_mode(pca, false);
I admit I didn't grasp all the PM framework details, but I wonder if
it's right to first call set_sleep_mode(true) and then in some cases to
false again.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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