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SubjectRe: [PATCH v3 3/3] misc: eeprom: at24: register nvmem only after eeprom is ready to use
Hi Bartosz,

On Mon, Aug 31, 2020 at 07:21:39PM +0200, Bartosz Golaszewski wrote:
> On Mon, Aug 31, 2020 at 3:56 AM Vadym Kochan <vadym.kochan@plvision.eu> wrote:
> >
> > During nvmem_register() the nvmem core sends notifications when:
> >
> > - cell added
> > - nvmem added
> >
> > and during these notifications some callback func may access the nvmem
> > device, which will fail in case of at24 eeprom because regulator and pm
> > are enabled after nvmem_register().
> >
> > Signed-off-by: Vadym Kochan <vadym.kochan@plvision.eu>
> > ---
> > v3:
> > 1) at24 driver enables regulator and pm state machine after nvmem
> > registration which does not allow to use it on handing NVMEM_PRE_ADD event.
> >
> > drivers/misc/eeprom/at24.c | 11 +++++++----
> > 1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> > index 2591c21b2b5d..26a23abc053d 100644
> > --- a/drivers/misc/eeprom/at24.c
> > +++ b/drivers/misc/eeprom/at24.c
> > @@ -692,10 +692,6 @@ static int at24_probe(struct i2c_client *client)
> > nvmem_config.word_size = 1;
> > nvmem_config.size = byte_len;
> >
> > - at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
> > - if (IS_ERR(at24->nvmem))
> > - return PTR_ERR(at24->nvmem);
> > -
> > i2c_set_clientdata(client, at24);
> >
> > err = regulator_enable(at24->vcc_reg);
> > @@ -708,6 +704,13 @@ static int at24_probe(struct i2c_client *client)
> > pm_runtime_set_active(dev);
> > pm_runtime_enable(dev);
> >
> > + at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
> > + if (IS_ERR(at24->nvmem)) {
> > + pm_runtime_disable(dev);
> > + regulator_disable(at24->vcc_reg);
> > + return PTR_ERR(at24->nvmem);
> > + }
> > +
> > /*
> > * Perform a one-byte test read to verify that the
> > * chip is functional.
> > --
> > 2.17.1
> >
>
> Good catch! Thanks for the patch. Can I queue it for fixes
> independently from the earlier patches in this series?
>
> Bart

Sure.

Regards,
Vadym Kochan

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