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SubjectRe: [PATCH v3 5/6] i2c: Add Actions Semiconductor Owl family S900 I2C driver
Hi Andy,

On Sun, Jul 01, 2018 at 12:11:00AM +0300, Andy Shevchenko wrote:
> On Sat, Jun 30, 2018 at 4:33 PM, Manivannan Sadhasivam
> <manivannan.sadhasivam@linaro.org> wrote:
> > Add Actions Semiconductor Owl family S900 I2C driver.
>
> Thanks for an update. Few left comments and it would LGTM.
>

Thanks :)

> > +static int owl_i2c_reset(struct owl_i2c_dev *i2c_dev)
> > +{
>
> > + mdelay(1);
>
> But now, since it's not used in atomic context, we may switch to
> usleep_range() / msleep() instead.
>

okay, will use msleep()

> > + owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
> > + OWL_I2C_CTL_EN, true);
> > +
>
> > + /* Wait 50ms for FIFO reset complete */
> > + do {
>
> > + mdelay(1);
>
> Especially in this case it's very important.
>

Okay.

> > + } while (timeout++ < OWL_I2C_MAX_RETRIES);
>
> > +}
>
> > + val = (i2c_dev->clk_rate + i2c_dev->bus_freq * 16 - 1) /
> > + (i2c_dev->bus_freq * 16);
>
> This is effectively DIV_ROUND_UP(->clk_rate, ->bus_freq * 16).
>

Ack.

> > + /*
> > + * By default, 0 will be returned if interrupt occurred but no
> > + * read or write happened. Else if msg_ptr equals to message length,
> > + * message count will be returned.
> > + */
>
> > + if (i2c_dev->msg_ptr == msg->len)
> > + ret = num;
>
> I dunno if
>
> ret = ->msg_ptr == len ? num : 0;
>
> would be slightly more explicit (yes, I aware about ret == 0).
>
> Up to you to choose.
>

As per Peter's comment, returning 0 will get changed to an error value.
Will use this pattern once we settle with a proper error value.

> > + /* We support only frequencies of 100k and 400k for now */
> > + if (i2c_dev->bus_freq != OWL_I2C_DEF_SPEED_HZ &&
> > + i2c_dev->bus_freq > OWL_I2C_MAX_SPEED_HZ) {
>
> I think it should be != in the second case as well.
>

yeah, agree. We don't support any other frequencies now.

Thanks,
Mani

> > + dev_err(dev, "invalid clock-frequency %d\n", i2c_dev->bus_freq);
> > + return -EINVAL;
> > + }
>
> --
> With Best Regards,
> Andy Shevchenko

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