Re: [PATCH v4] i2c: sh_mobile: implement atomic transfers

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Uli,

On Mon, Sep 28, 2020 at 6:09 PM Ulrich Hecht <uli+renesas@fpond.eu> wrote:
> Implements atomic transfers to fix reboot/shutdown on r8a7790 Lager and
> similar boards.
>
> Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>
> Hi!
>
> Another minor change in the atomic code path in start_ch() as suggested by
> Geert. All power management-related issues have been decided to be solved
> outside this driver, so we should be done here.
>
> CU
> Uli
>
>
> Changes since v3:
> - cut atomic_xfer code path short in start_ch()

Thanks for the update!

> --- a/drivers/i2c/busses/i2c-sh_mobile.c
> +++ b/drivers/i2c/busses/i2c-sh_mobile.c

> +static int sh_mobile_i2c_xfer_atomic(struct i2c_adapter *adapter,
> +                                    struct i2c_msg *msgs,
> +                                    int num)
> +{
> +       struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);

To make sure external conditions are satisfied, and we never deadlock,
as discussed in v3?

    if (pd->dev->power.is_suspended)
            return -EPERM;  /* any other suitable error code? */

> +
> +       pd->atomic_xfer = true;
> +       return sh_mobile_xfer(pd, msgs, num);
> +}
Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds