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. Patch 2 is just removing the pwm_enable() call from the ->set_voltage() implementation (pwm_enable() is already called in the reg->enable() hook). Patches 3 to 8 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 9 to 12 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 13 and 14. Best Regards, Boris Boris Brezillon (14): pwm: Add new helpers to create/manipulate PWM states regulator: pwm: Drop unneeded pwm_enable() call 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 .../bindings/regulator/pwm-regulator.txt | 12 ++ drivers/pwm/pwm-rockchip.c | 182 +++++++++++++++------ drivers/pwm/pwm-sti.c | 55 ++++++- drivers/regulator/pwm-regulator.c | 159 ++++++++++++------ include/linux/pwm.h | 81 +++++++++ 5 files changed, 391 insertions(+), 98 deletions(-) -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
