On Wed, May 08, 2024 at 05:12:51PM +0100, Bryan O'Donoghue wrote:
> On 06/05/2024 16:08, Johan Hovold wrote:
> > Request and deassert any (optional) reset gpio during probe in case it
> > has been left asserted by the boot firmware.
> >
> > Note the reset line is not asserted to avoid reverting to the default
> > I2C address in case the firmware has configured an alternate address.
> > @@ -169,6 +171,10 @@ static int pm8008_probe(struct i2c_client *client)
> >
> > i2c_set_clientdata(client, regmap);
> >
> > + reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> > + if (IS_ERR(reset))
> > + return PTR_ERR(reset);
> > +
> > if (of_property_read_bool(dev->of_node, "interrupt-controller")) {
> > rc = devm_regmap_add_irq_chip(dev, regmap, client->irq,
> > IRQF_SHARED, 0, &pm8008_irq_chip, &irq_data);
>
> So not resetting is fine and I understand you want to retain the address
> given by the firmware, I think that's the right thing to do.
> In addition to adding a small delay suggested by Andy - a few
> microseconds pick a number, I think you should verify the chip is out of
> reset as we would do with many other i2c devices.
> In this case, suggest reading REVID_PERPH_TYPE @ 0x104 and
> REVID_PERPH_SUBTYPE @ 0x105
>
> REVID_PERPH_TYPE @ 0x104 == 0x51 (PMIC)
> REVID_PERPH_SUBYTE @ 0x105 == 0x2C (PM8008)
I'll consider it for v2.
Johan
