linux-kernel - Re: [PATCH V1 2/2] i2c: iproc: add slave pec support

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Date:   Thu, 16 Jul 2020 22:49:14 +0530
From:   Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Wolfram Sang <wsa@...nel.org>,
        linux-i2c <linux-i2c@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
        Lori Hikichi <lori.hikichi@...adcom.com>,
        Robert Richter <rrichter@...vell.com>,
        Nishka Dasgupta <nishkadg.linux@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH V1 2/2] i2c: iproc: add slave pec support

Hi Andy,

On Thu, Jul 16, 2020 at 3:44 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> On Thu, Jul 16, 2020 at 11:14 AM Rayagonda Kokatanur
> <rayagonda.kokatanur@...adcom.com> wrote:
> >
> > Iproc supports PEC computation and checking in both Master
> > and Slave mode.
> >
> > This patch adds support for PEC in slave mode.
>
> ...
>
> > -#define S_RX_PEC_ERR_SHIFT           29
> > +#define S_RX_PEC_ERR_SHIFT           28
> > +#define S_RX_PEC_ERR_MASK            0x3
> > +#define S_RX_PEC_ERR                 0x1
>
> This needs to be explained in the commit message, in particular why
> this change makes no regression.

I didn't get what do you mean by "no regression", please elaborate.

>
> ...
>
> > +static int bcm_iproc_smbus_check_slave_pec(struct bcm_iproc_i2c_dev *iproc_i2c,
> > +                                          u32 val)
> > +{
> > +       u8 err_status;
>
> > +       int ret = 0;
>
> Completely redundant variable.
>
> > +       if (!iproc_i2c->en_s_pec)
> > +               return ret;
>
> return 0;
>
> > +       err_status = (u8)((val >> S_RX_PEC_ERR_SHIFT) & S_RX_PEC_ERR_MASK);
>
> Why casting?
>
> > +       if (err_status == S_RX_PEC_ERR) {
> > +               dev_err(iproc_i2c->device, "Slave PEC error\n");
>
> > +               ret = -EBADMSG;
>
> return ...
>
> > +       }
> > +
> > +       return ret;
>
> return 0;
>
> > +}
>
> ...
>
> > +                       if (rx_status == I2C_SLAVE_RX_END) {
> > +                               int ret;
> > +
> > +                               ret = bcm_iproc_smbus_check_slave_pec(iproc_i2c,
> > +                                                                     val);
>
> One line looks better.

Yes, but to have 80 char per line, I have to do this.
>
> > +                               if (!ret)
>
> Why not positive conditional?

Thank you for your review.
Will fix all above.

Best regards,
Rayagonda

>
> > +                                       i2c_slave_event(iproc_i2c->slave,
> > +                                                       I2C_SLAVE_STOP, &value);
> > +                               else
> > +                                       i2c_slave_event(iproc_i2c->slave,
> > +                                                       I2C_SLAVE_PEC_ERR,
> > +                                                       &value);
> > +                       }
>
> --
> With Best Regards,
> Andy Shevchenko