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References: <20220713031547.11641-1-allen.chen@ite.com.tw>
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From:   Robert Foss <robert.foss@linaro.org>
Date:   Tue, 19 Jul 2022 17:26:30 +0200
Message-ID: <CAG3jFyvDWXZsSKaztKgbAUOY8DNFb81KvSpG5fQC=t1dUZp8oA@mail.gmail.com>
Subject: Re: [PATCH v2] drm/bridge: it6505: Add i2c api power on check
To:     allen <allen.chen@ite.com.tw>
Cc:     Jau-Chih Tseng <Jau-Chih.Tseng@ite.com.tw>,
        Kenneth Hung <Kenneth.Hung@ite.com.tw>,
        Hermes Wu <Hermes.Wu@ite.com.tw>,
        Pin-yen Lin <treapking@google.com>,
        Pin-Yen Lin <treapking@chromium.org>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        "open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>,
        open list <linux-kernel@vger.kernel.org>
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On Wed, 13 Jul 2022 at 05:16, allen <allen.chen@ite.com.tw> wrote:
>
> From: allen chen <allen.chen@ite.com.tw>
>
> Use i2c bus to read/write when it6505 power off will occur i2c error.
> Add this check will prevent i2c error when it6505 power off.
>
> Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
> Signed-off-by: Allen Chen <allen.chen@ite.com.tw>
> Reviewed-by: Robert Foss <robert.foss@linaro.org>
> ---
>  drivers/gpu/drm/bridge/ite-it6505.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
> index aa5e0aa1af85..cfd2c3275dc5 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -518,6 +518,9 @@ static int it6505_read(struct it6505 *it6505, unsigned int reg_addr)
>         int err;
>         struct device *dev = &it6505->client->dev;
>
> +       if (!it6505->powered)
> +               return -ENODEV;
> +
>         err = regmap_read(it6505->regmap, reg_addr, &value);
>         if (err < 0) {
>                 dev_err(dev, "read failed reg[0x%x] err: %d", reg_addr, err);
> @@ -533,6 +536,9 @@ static int it6505_write(struct it6505 *it6505, unsigned int reg_addr,
>         int err;
>         struct device *dev = &it6505->client->dev;
>
> +       if (!it6505->powered)
> +               return -ENODEV;
> +
>         err = regmap_write(it6505->regmap, reg_addr, reg_val);
>
>         if (err < 0) {
> @@ -550,6 +556,9 @@ static int it6505_set_bits(struct it6505 *it6505, unsigned int reg,
>         int err;
>         struct device *dev = &it6505->client->dev;
>
> +       if (!it6505->powered)
> +               return -ENODEV;
> +
>         err = regmap_update_bits(it6505->regmap, reg, mask, value);
>         if (err < 0) {
>                 dev_err(dev, "write reg[0x%x] = 0x%x mask = 0x%x failed err %d",
> @@ -2553,13 +2562,12 @@ static int it6505_poweron(struct it6505 *it6505)
>                 usleep_range(10000, 20000);
>         }
>
> +       it6505->powered = true;
>         it6505_reset_logic(it6505);
>         it6505_int_mask_enable(it6505);
>         it6505_init(it6505);
>         it6505_lane_off(it6505);
>
> -       it6505->powered = true;
> -
>         return 0;
>  }
>
> --
> 2.25.1
>

This patch no longer applies to the drm-misc-next tree, could you
rebase it and send out a v3?