Thread (4 messages) 4 messages, 2 authors, 2026-05-25

Re: [PATCH] misc: eeprom: at24: Make VCC supply description requirement optional

From: Paul Menzel <hidden>
Date: 2026-05-25 07:08:26
Also in: linux-i2c, lkml

Dear Mark,


Thank you for taking the time to review and respond.


Am 25.05.26 um 00:07 schrieb Mark Brown:
On Sun, May 24, 2026 at 10:05:33AM +0200, Paul Menzel wrote:
quoted
Some platforms (e.g. IBM Power System S822LC (8335-GCA POWER8)) do not
describe the EEPROM’s VCC supply in firmware-provided device trees.
Using `devm_regulator_get()` on such systems falls back to a dummy
regulator with a kernel warning:
quoted
Switch to `devm_regulator_get_optional()` and treat -ENODEV as “no
supply described”. When `vcc_reg` is NULL, skip all
regulator_enable/disable calls; the hardware is assumed to be always
powered. Linux now logs:
This is not appropriate unless the device can actually operate without
power, any driver could be used in a system where the firmware does not
describe the regultors and it'd obviously be pointless and error prone
to scatter bodges like this on every single call to a regulator API
function.
How should the warning on the POWER server be addressed then?


Kind regards,

Paul
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