Re: [PATCH v2 00/13] regulator: pwm: various improvements

Hi Boris,

Am Mittwoch, 8. Juni 2016, 18:34:35 schrieb Boris Brezillon:

This patch series series aims at adding two important features to the
pwm-regulator driver.

The first one is the support for 'smooth handover' between the
bootloader and the kernel. This is mainly solving problems we have when
the PWM is controlling a critical regulator (like the one powering the
DDR chip). Currently, when the PWM regulator acquire the PWM device it
assumes it was off and it's safe to change the configuration before
enabling it, which can generate glitches on the PWM signal which in turn
generated glitches on the output voltage.
To solve that we've introduced support for hardware readout to the
PWM framework, so that the PWM regulator driver can adjust the PWM
a probe time and avoid glitches.
Atomic update is also helping in this regard.

[...]

The second feature we add to the driver is the capability of using
a sub duty_cycle range in continuous mode. By default the regulator
is assuming that min_uV is achieved with a 0% dutycyle and max_uV
with a 100% dutycycle, but this is not necessarily true.
Moreover, in some cases (when the PWM device does not support
polarity inversion), we might have min_uV at 100% and max_uV at 0%.
Hence the addition of new properties to the existing DT bindings.
The feature is added in patch 12 and 13.

I've tested this series on a rk3288-veyron chromebook and both the backlight-
pwm as well as the pwm-regulator still work as expected, so for everything 
except the STI parts:

Tested-by: Heiko Stuebner <heiko@sntech.de>