| Message ID | 20210406164140.81423-3-clemens.gruber@pqgruber.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [v7,1/8] pwm: pca9685: Switch to atomic API | expand |
On Tue, Apr 06, 2021 at 06:41:35PM +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. > > Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com> > --- > Changes since v6: > - Improved !CONFIG_PM handling (wake it up without putting it to sleep > first) > > drivers/pwm/pwm-pca9685.c | 26 +++++++++++++++++++------- > 1 file changed, 19 insertions(+), 7 deletions(-) > > diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c > index d4474c5ff96f..0bcec04b138a 100644 > --- a/drivers/pwm/pwm-pca9685.c > +++ b/drivers/pwm/pwm-pca9685.c > @@ -474,13 +474,18 @@ 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 > - */ > - pm_runtime_enable(&client->dev); > + if (IS_ENABLED(CONFIG_PM)) { This looks odd to me. I've seen similar constructs, but they usually go something like this (I think): pm_runtime_enable(&client->dev); if (!pm_runtime_enabled(&client->dev)) { /* resume device */ } Which I guess in your would be somewhat the opposite and it wouldn't actually resume the device but rather put it to sleep. Perhaps something like this: pm_runtime_enable(&client->dev); if (pm_runtime_enabled(&client->dev)) { pca9685_set_sleep_mode(pca, true); pm_runtime_set_suspended(&client->dev); } else { /* wake the chip up on non-PM environments */ pca9685_set_sleep_mode(pca, false); } ? I think that's slightly more correct than your original because it takes into account things like sysfs power control and such. It also doesn't rely on the config option alone but instead uses the runtime PM API to achieve this more transparently. Thierry
On Fri, Apr 09, 2021 at 03:03:20PM +0200, Thierry Reding wrote: > On Tue, Apr 06, 2021 at 06:41:35PM +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. > > > > Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com> > > --- > > Changes since v6: > > - Improved !CONFIG_PM handling (wake it up without putting it to sleep > > first) > > > > drivers/pwm/pwm-pca9685.c | 26 +++++++++++++++++++------- > > 1 file changed, 19 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c > > index d4474c5ff96f..0bcec04b138a 100644 > > --- a/drivers/pwm/pwm-pca9685.c > > +++ b/drivers/pwm/pwm-pca9685.c > > @@ -474,13 +474,18 @@ 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 > > - */ > > - pm_runtime_enable(&client->dev); > > + if (IS_ENABLED(CONFIG_PM)) { > > This looks odd to me. I've seen similar constructs, but they usually go > something like this (I think): > > pm_runtime_enable(&client->dev); > > if (!pm_runtime_enabled(&client->dev)) { > /* resume device */ > } > > Which I guess in your would be somewhat the opposite and it wouldn't > actually resume the device but rather put it to sleep. Yes, I wanted to keep it in sleep mode if runtime PM is supported (to be woken up later) and otherwise just wake it up in probe. > > Perhaps something like this: > > pm_runtime_enable(&client->dev); > > if (pm_runtime_enabled(&client->dev)) { > pca9685_set_sleep_mode(pca, true); > pm_runtime_set_suspended(&client->dev); > } else { > /* wake the chip up on non-PM environments */ > pca9685_set_sleep_mode(pca, false); > } > > ? I think that's slightly more correct than your original because it > takes into account things like sysfs power control and such. It also > doesn't rely on the config option alone but instead uses the runtime > PM API to achieve this more transparently. Ah, yes, I missed the fact that runtime could be disabled 'at runtime' via sysfs as well, so yes, that's more correct and pm_runtime_enabled will just return false if !CONFIG_PM, so that should work as well. Thanks, Clemens
diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c index d4474c5ff96f..0bcec04b138a 100644 --- a/drivers/pwm/pwm-pca9685.c +++ b/drivers/pwm/pwm-pca9685.c @@ -474,13 +474,18 @@ 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 - */ - pm_runtime_enable(&client->dev); + if (IS_ENABLED(CONFIG_PM)) { + /* + * 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); + } else { + /* Wake the chip up on non-PM environments */ + pca9685_set_sleep_mode(pca, false); + } return 0; } @@ -493,7 +498,14 @@ static int pca9685_pwm_remove(struct i2c_client *client) ret = pwmchip_remove(&pca->chip); if (ret) return ret; + pm_runtime_disable(&client->dev); + + if (!IS_ENABLED(CONFIG_PM)) { + /* Put chip in sleep state on non-PM environments */ + pca9685_set_sleep_mode(pca, true); + } + return 0; }
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. Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com> --- Changes since v6: - Improved !CONFIG_PM handling (wake it up without putting it to sleep first) drivers/pwm/pwm-pca9685.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-)