Re: [PATCH 4/4] i2c: rcar: protect against supurious interrupts on V3U

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Linux I2C <linux-i2c@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Subject: Re: [PATCH 4/4] i2c: rcar: protect against supurious interrupts on V3U
Date: Mon, 28 Dec 2020 14:37:32 +0100	[thread overview]
Message-ID: <CAMuHMdW48sFLernApzcQ7Dqz90kX18d9+9e9ytQ=rVQ2hWD_4A@mail.gmail.com> (raw)
In-Reply-To: <20201223172154.34462-5-wsa+renesas@sang-engineering.com>

Hi Wolfram,

On Wed, Dec 23, 2020 at 6:24 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> V3U creates spurious interrupts which we need to handle. This costs time
> until BUS_PHASE_DATA can be activated which is problematic for Gen2 SoCs
> and earlier. Because of this we introduce two interrupt handlers here
> which will call a generic main irq function once the timing critical
> stuff is done.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Thanks for your patch!

> --- a/drivers/i2c/busses/i2c-rcar.c
> +++ b/drivers/i2c/busses/i2c-rcar.c
> @@ -625,20 +625,11 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
>   * generated. It turned out that taking a spinlock at the beginning of the ISR
>   * was already causing repeated messages. Thus, this driver was converted to
>   * the now lockless behaviour. Please keep this in mind when hacking the driver.
> + * R-Car Gen3 seems to have this fixed but earlier versions than R-Car Gen2 are

s/than/like/?

> + * likely affected. Therefore, we have different interrupt handler entries.
>   */

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