On Tue, Oct 08, 2019 at 01:41:27PM +0200, Fabrice Gasnier wrote: > Add a comment to better describe the purpose of breakinput feature that > can be found on some STM32 timer instances. Briefly comment on the > characteristics of this input for PWM, and pinmuxing as suggested in [1]. > > [1] https://lkml.org/lkml/2019/10/1/207 > > Signed-off-by: Fabrice Gasnier <[email protected]> > --- > drivers/pwm/pwm-stm32.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c > index 359b085..6406ebb 100644 > --- a/drivers/pwm/pwm-stm32.c > +++ b/drivers/pwm/pwm-stm32.c > @@ -522,8 +522,14 @@ static int stm32_pwm_apply_breakinputs(struct stm32_pwm > *priv, > sizeof(struct stm32_breakinput)); > > /* > + * Some timer instances can have BRK input pins (e.g. basically a fault > + * pin from the output power stage). The break feature allows a safe > + * shut-down of the PWM outputs to a predefined state. Further details > + * are available in application note AN4277, "Using STM32 device PWM > + * shut-down features..."
Without having read the application note I don't understand the purpose. Not sure if this should be a show stopper though. > * Because "st,breakinput" parameter is optional do not make probe > - * failed if it doesn't exist. > + * failed if it doesn't exist. The pinctrl handle must hold the BRK > + * pin(s) when using "st,breakinput" property. Is this a comment that has a better place in the binding doc? Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
