.../devicetree/bindings/rtc/st,stm32-rtc.yaml | 28 ++ drivers/rtc/Kconfig | 6 + drivers/rtc/rtc-stm32.c | 281 ++++++++++++++++++ 3 files changed, 315 insertions(+)
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>;
};
[1] https://lore.kernel.org/linux-arm-kernel/20220504130617.331290-5-valentin.caron@foss.st.com/t/#m37935e92315e22bbe085775096175afc05b7ff09
Since v2:
- Modify Kconfig after (a lot of) robots alert:
+ https://lore.kernel.org/oe-kbuild-all/202407190654.I3RI7WfP-lkp@intel.com/
+ https://lore.kernel.org/oe-kbuild-all/202407191258.1oitwwMV-lkp@intel.com/
+ https://lore.kernel.org/oe-kbuild-all/202407200400.NnW2fJ0q-lkp@intel.com/
+ https://lore.kernel.org/oe-kbuild-all/202407181525.BRNKqmNf-lkp@intel.com/
+ https://lore.kernel.org/oe-kbuild-all/202407191830.8bh5dJ09-lkp@intel.com/
Make RTC_DRV_STM32 depends on OF, PINCTRL and COMMON_CLK as they are menuconfig entry.
Make RTC_DRV_STM32 select PINCONF, PINCONF_GENERIC and PINMUX as they config entry.
Since v1:
- Select PINMUX and PINCONF_GENERIC to solve:
https://lore.kernel.org/oe-kbuild-all/202407130943.ie6n2Orh-lkp@intel.com/
- Make stm32_rtc_pinctrl_pins as static to solve:
https://lore.kernel.org/oe-kbuild-all/202407130612.OEicZbNE-lkp@intel.com/
- Change "depends on" to "select" COMMON_CLK config
- Modify regex in dt-binding to avoid properties like "rtc--123" as valid ones.
Valentin Caron (4):
dt-bindings: rtc: stm32: describe pinmux nodes
rtc: stm32: add pinctrl and pinmux interfaces
rtc: stm32: add Low Speed Clock Output (LSCO) support
rtc: stm32: add alarm A out feature
.../devicetree/bindings/rtc/st,stm32-rtc.yaml | 28 ++
drivers/rtc/Kconfig | 6 +
drivers/rtc/rtc-stm32.c | 281 ++++++++++++++++++
3 files changed, 315 insertions(+)
--
2.25.1
On Mon, 22 Jul 2024 18:00:18 +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.
>
> [...]
Applied, thanks!
[1/4] dt-bindings: rtc: stm32: describe pinmux nodes
https://git.kernel.org/abelloni/c/5b19519d4e6f
[2/4] rtc: stm32: add pinctrl and pinmux interfaces
https://git.kernel.org/abelloni/c/16ad2bc09efb
[3/4] rtc: stm32: add Low Speed Clock Output (LSCO) support
https://git.kernel.org/abelloni/c/bb7b0df2be5c
[4/4] rtc: stm32: add alarm A out feature
https://git.kernel.org/abelloni/c/04dcadb87da6
Best regards,
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Hi Valentin,
On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron
<valentin.caron@foss.st.com> wrote:
> This series adds a pinctrl/pinmux interface to control STM32 RTC outputs.
Interesting! I think it is the first pin controller outside on
drivers/pinctrl in the kernel tree.
Please include me and the linux-gpio@vger.kernel.org list in
subsequent postings, I want to be sure what gets merged here
and I only noticed this from the LWN driver patches summary.
> 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>;
So the first one is a generic pin control setting and the second
one is a hog for the pins defined by the device itself.
It's clever, and works. Nice work!
(There should probably be a comment in the device tree to say
what is going on so people reading it are not confused.)
> /* 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";
> };
Yours,
Linus Walleij
Hello Linus, On 26/07/2024 22:37:21+0200, Linus Walleij wrote: > On Mon, Jul 22, 2024 at 6:02 PM Valentin Caron > <valentin.caron@foss.st.com> wrote: > > > This series adds a pinctrl/pinmux interface to control STM32 RTC outputs. > > Interesting! I think it is the first pin controller outside on > drivers/pinctrl in the kernel tree. Actually, we have rtc-omap which does this too. I've been pushing for more RTC to do this instead of defining custom dt bindings to do what boils down to pinmuxing. > > Please include me and the linux-gpio@vger.kernel.org list in > subsequent postings, I want to be sure what gets merged here > and I only noticed this from the LWN driver patches summary. I'll also ensure you get copied on pinctrl related patches. -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
© 2016 - 2025 Red Hat, Inc.