Re: [PATCH v11 6/7] power: reset: add PSCR NVMEM Driver for Recording Power State Change Reasons

[Francesco Valla <francesco@valla.it>]

Hi Oleksij,

On Wednesday, 18 June 2025 at 14:02:54 Oleksij Rempel <o.rempel@pengutronix.de> wrote:
> This driver utilizes the Power State Change Reasons Recording (PSCRR)
> framework to store specific power state change information, such as
> shutdown or reboot reasons, into a designated non-volatile memory
> (NVMEM) cell.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
> changes v6:
> - rename pscr_reason to psc_reason
> changes v5:
> - avoid a build against NVMEM=m
> changes v4:
> - remove devicetree dependencies
> ---
>  drivers/power/reset/Kconfig       |  22 +++
>  drivers/power/reset/Makefile      |   1 +
>  drivers/power/reset/pscrr-nvmem.c | 254 ++++++++++++++++++++++++++++++
>  3 files changed, 277 insertions(+)
>  create mode 100644 drivers/power/reset/pscrr-nvmem.c
> 

Tested-by: Francesco Valla <francesco@valla.it>

I tested this on a i.MX93 FRDM using the on-board EEPROM as storage and
a single-byte cell. Unfortunately, the on-board RTC does not have a
scratchpad.

PSCR was set in two different ways during subsequent tests:

 - manually from userspace
 - simulating a over-temperature condition through the emul_temp sysfs

In both cases, it was re-read correctly after reboot.

This will be very useful to detect and debug anomalous shutdowns or
reboots on the field.

Thank you!

Regards,
Francesco