[PATCH 0/4] rtc: stm32: add pinctrl interface to handle RTC outs

Valentin CARON valentin.caron at foss.st.com
Wed Jul 17 00:57:55 PDT 2024



On 7/15/24 23:12, Alexandre Belloni wrote:
> Hello,
> 
> On 11/07/2024 16:08:39+0200, Valentin Caron wrote:
>> This series adds a pinctrl/pinmux interface to control STM32 RTC outputs.
>>
>> Theses two signals output are possible:
>>   - LSCO (Low Speed Clock Output) that allow to output LSE clock on a pin.
>>     On STM32MPU Discovery boards, this feature is used to generate a clock
>>     to Wifi/Bluetooth module.
>>   - Alarm out that allow to send a pulse on a pin when alarm A of the RTC
>>     expires.
>>
>> First attempt [1] was based on 'st,' vendor properties, this one is based
>> on pinctrl and pinmux framework.
>>
>> As device-trees will be upstreamed separately, here is an example:
>>
>> stm32-pinctrl {
>>      rtc_rsvd_pins_a: rtc-rsvd-0 {
>>          pins {
>>              pinmux = <STM32_PINMUX('B', 2, AF1)>, /* OUT2 */
>>                       <STM32_PINMUX('I', 8, ANALOG)>; /* OUT2_RMP */
>>          };
>>      };
>> };
>>
>> stm32-rtc {
>>      pinctrl-0 = <&rtc_rsvd_pins_a &rtc_alarma_pins_a>;
>>
>>      /* Enable by foo-device */
>>      rtc_lsco_pins_a: rtc-lsco-0 {
>>          pins = "out2_rmp";
>>          function = "lsco";
>>      };
>>
>>      /* Enable by stm32-rtc hog */
>>      rtc_alarma_pins_a: rtc-alarma-0 {
>>          pins = "out2";
>>          function = "alarm-a";
>>      };
>> };
>>
>> foo-device {
>>      pinctrl-0 = <&rtc_lsco_pins_a>;
>> };
>>
> 
> This all seems good to me, I let you fix the various issues that have
> been reported. I was just wondering whether the LSCO clock was registered
> early enough to be used but I guess you tested that.
> 

Hi,

Here it is:
https://lore.kernel.org/lkml/20240717074835.2210411-1valentin.caron@foss.st.com/

Yes it works fine, RTC is probed early enough in the boot sequence, and 
so Wifi/BT module does not have an issue to get the LSCO clock.

Thanks,
Valentin



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