linux-kernel - Re: [PATCH v2 3/3] i2c: mpc: implement erratum A-004447 workaround

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Message-ID: <CAHp75VcEzgKjOD6WQ1=YAwK_hhZr=XtcmXZL8rK78gb7iXDbDg@mail.gmail.com>
Date:   Fri, 7 May 2021 14:46:26 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Chris Packham <chris.packham@...iedtelesis.co.nz>
Cc:     Wolfram Sang <wsa@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rob Herring <robh+dt@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        linux-i2c <linux-i2c@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        "open list:LINUX FOR POWERPC PA SEMI PWRFICIENT" 
        <linuxppc-dev@...ts.ozlabs.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/3] i2c: mpc: implement erratum A-004447 workaround

On Fri, May 7, 2021 at 3:40 AM Chris Packham
<chris.packham@...iedtelesis.co.nz> wrote:
>
> The P2040/P2041 has an erratum where the normal i2c recovery mechanism
> does not work. Implement the alternative recovery mechanism documented
> in the P2040 Chip Errata Rev Q.

Thanks.

> +static int i2c_mpc_wait_sr(struct mpc_i2c *i2c, int mask)
> +{
> +       int ret;
> +       u8 val;
> +
> +       ret = readb_poll_timeout(i2c->base + MPC_I2C_SR, val,
> +                                val & mask, 0, 100);
> +
> +       return ret;
> +}

So, now you may shrink it even further, i.e.

       void __iomem *sr = i2c->base + MPC_I2C_SR;
       u8 val;

       return readb_poll_timeout(sr, val, val & mask, 0, 100);

-- 
With Best Regards,
Andy Shevchenko