On Tue, Jun 14, 2016 at 11:13:08AM +0200, Boris Brezillon wrote: > Hello, > > 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. > > Patch 1 is adding convenient helpers (at the PWM level) that will be > used by the PWM regulator driver. > Patches 2 to 7 are preparing everything on the PWM driver side to make > hardware readout available to all platforms using the PWM regulator > driver (rockchip and sti). > Patches 8 to 11 are making use of the atomic update and hardware readout > features to implement this smooth handover. > > 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. > > Best Regards, > > Boris > > Changes since v2: > - add Heiko's Tested-by > - split patch 1 in 2 patches > - rework the documentation > - rename pwm_prepare_new_state() into pwm_init_state() > - make pwm_set_relative_duty_cycle() return an error code when scale > or duty_cycle are inconsistent > > Changes since v1: > - dropped already applied patches > - added R-b/A-b/T-b tags > - s/readl/readl_relaxed/ in patch 3 (as suggested by Brian) > - fixed pwm-regulator DT binding doc > - added some comments in the code > - replaced pwm_get_state() + if (state.enabled) by if (pwm_is_enabled()) > > Boris Brezillon (14): > pwm: Add an helper to prepare a new PWM state > pwm: Add two helpers to ease relative duty cycle manipulation > pwm: rockchip: Fix period and duty_cycle approximation > pwm: rockchip: Add support for hardware readout > pwm: rockchip: Avoid glitches on already running PWMs > pwm: rockchip: Add support for atomic update > pwm: sti: Add support for hardware readout > pwm: sti: Avoid glitches on already running PWMs > regulator: pwm: Adjust PWM config at probe time > regulator: pwm: Switch to the atomic PWM API > regulator: pwm: Properly initialize the ->state field > regulator: pwm: Retrieve correct voltage > regulator: pwm: Support extra continuous mode cases > regulator: pwm: Document pwm-dutycycle-unit and pwm-dutycycle-range I've applied everything in this series to the PWM tree, except for the two pwm-sti driver patches, which I'd like to get an Acked-by from one of the maintainers. Mark, let me know how you'd like to handle the miniature conflict in the regulator-pwm driver that I mentioned in one of the patches. Thierry
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