On 10/8/19 4:45 PM, Uwe Kleine-König wrote: > 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.
Hi Uwe, I can rephrase this. Do you think the bellow comment would be more relevant and easy to understand ? /* * The break feature allows a safe shut-down of the PWM outputs. * It's based on the BRK event signal defined in the dt-bindings * by <index level filter> values. * Because "st,breakinput" parameter is optional do not make probe * failed if it doesn't exist. */ > >> * 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? You're right, this is unneeded here. I'll remove this. Please advise, BR, Fabrice > > Best regards > Uwe > >
