lkml.org 
[lkml]   [2019]   [Oct]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] pwm: stm32: add comment to better describe breakinput feature
From
Date
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 <fabrice.gasnier@st.com>
>> ---
>> 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
>
>

\
 
 \ /
  Last update: 2019-10-09 11:52    [W:0.038 / U:12.516 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site