This is an attempt to deal with i.MX SoC PWM HW limitation. When a pad is configured as a PWM output the output level is always 0V if the PWM block is disabled. This can cause problems when inverted PWM signal is needed to drive the connected circuit. With inverted output duty cycle = 0% corresponds to high output level and duty cycle = 100% corresponds to low output level. This means that whenever the PWM block is disabled the connected circuit is fed with 100% duty cycle. This binding is totally optional and current users are not affected. The idea is to use two new pinctrl states, "pwm" and "gpio", instead of the "default" pinctrl state. The gpio state is selected when PWM is disabled and the pwm pinctrl state is selected when PWM is enabled. In the gpio state level on the output is controlled by the internal pull-up. Michal Vokáč (2): dt-bindings: pwm: imx: Allow switching PWM output between PWM and GPIO pwm: imx: Configure output to GPIO in disabled state Documentation/devicetree/bindings/pwm/imx-pwm.txt | 49 +++++++++++++++ drivers/pwm/pwm-imx.c | 77 +++++++++++++++++++++++ 2 files changed, 126 insertions(+) -- 2.1.4
