On Tue, Apr 14, 2020 at 07:42:24PM +0300, Andy Shevchenko wrote:
> On Tue, Apr 14, 2020 at 6:34 PM <mani@xxxxxxxxxx> wrote:
> >
> > From: Manivannan Sadhasivam <mani@xxxxxxxxxx>
> >
> > CCS811 VOC sensor exposes nRESET and nWAKE pins which can be connected
> > to GPIO pins of the host controller. These pins can be used to externally
> > release the device from reset and also to wake it up before any I2C
> > transaction. The initial driver support assumed that the nRESET pin is not
> > connected and the nWAKE pin is tied to ground.
> >
> > This commit improves it by adding support for controlling those two pins
> > externally using a host controller. For the case of reset, if the hardware
> > reset is not available, the mechanism to do software reset is also added.
> >
> > As a side effect of doing this, the IIO device allocation needs to be
> > slightly moved to top of probe to make use of priv data early.
>
> Thank you for an update, my comments below.
>
> ...
>
> > + reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> > + GPIOD_OUT_LOW);
> > + if (IS_ERR(reset_gpio)) {
>
> > + dev_err(&client->dev, "Failed to acquire reset gpio\n");
>
> If it's a deferred probe, it would spam the log.
>
Hmm. But error is an error isn't it? Would you recommend doing a debug print
or completely removing the logging?
> > + return PTR_ERR(reset_gpio);
> > + }
>
> ...
>
> > + static const u8 reset_seq[] = {
> > + 0xFF, 0x11, 0xE5, 0x72, 0x8A,
> > + };
>
> I would suggest to comment above from where you got this and the
> meaning of the numbers.
>
The datasheet doesn't specify the meaning of these values. But will add a
comment. Btw, just noticed that 0xFF is not needed and only 4 values are
sufficient for SW reset.
Thanks,
Mani
> ...
>
> > + data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup",
> > + GPIOD_OUT_HIGH);
> > + if (IS_ERR(data->wakeup_gpio)) {
>
> > + dev_err(&client->dev, "Failed to acquire wakeup gpio\n");
>
> Ditto.
>
> > + return PTR_ERR(data->wakeup_gpio);
> > + }
>
> --
> With Best Regards,
> Andy Shevchenko
