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References: <20220618165747.55709-1-samuel@sholland.org> <20220618165747.55709-4-samuel@sholland.org>
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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Sun, 19 Jun 2022 13:34:12 +0200
Message-ID: <CAHp75VfM3L-bKOLoXTz67JCWq8UX6d-LvuYDxXMtTBznGOTgSA@mail.gmail.com>
Subject: Re: [PATCH v4 3/4] Input: pinephone-keyboard - Support the proxied
 I2C bus
To:     Samuel Holland <samuel@sholland.org>
Cc:     Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        linux-input <linux-input@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>, Ondrej Jirman <x@xff.cz>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Colin Ian King <colin.king@intel.com>,
        David Gow <davidgow@google.com>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Marco Felsch <m.felsch@pengutronix.de>,
        Mattijs Korpershoek <mkorpershoek@baylibre.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Yassine Oudjana <y.oudjana@protonmail.com>,
        "fengping.yu" <fengping.yu@mediatek.com>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        linux-sunxi@lists.linux.dev
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On Sat, Jun 18, 2022 at 7:12 PM Samuel Holland <samuel@sholland.org> wrote:
>
> The PinePhone keyboard case contains a battery managed by an integrated
> power bank IC. The power bank IC communicates over I2C, and the keyboard
> MCU firmware provides an interface to read and write its registers.
> Let's use this interface to implement a SMBus adapter, so we can reuse
> the driver for the power bank IC.

...

> +       /* Read back the command status until it passes or fails. */
> +       do {
> +               usleep_range(300, 500);
> +               ret = i2c_smbus_read_byte_data(client, PPKB_SYS_COMMAND);
> +       } while (ret == buf[2]);
> +       if (ret < 0)
> +               return ret;
> +       /* Commands return 0x00 on success and 0xff on failure. */
> +       if (ret)
> +               return -EIO;

Something to use from iopoll.h ?


-- 
With Best Regards,
Andy Shevchenko