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 <4bb22e77-b3f0-be07-5e8a-442c3aa3fd48@linaro.org>
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From:   Paulo Pavacic <pavacic.p@gmail.com>
Date:   Tue, 6 Jun 2023 09:36:39 +0200
Message-ID: <CAO9szn05edU_HZHVnREMZcwm6TbBa4psABoqSqLWghFc=KbV7w@mail.gmail.com>
Subject: Re: [PATCH v2 3/3] drm/panel-fannal-c3003: Add fannal c3004 DSI panel
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     neil.armstrong@linaro.org, sam@ravnborg.org, airlied@gmail.com,
        daniel@ffwll.ch, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
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Hello Krzysztof,

uto, 6. lip 2023. u 09:14 Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> napisao je:
>
> On 05/06/2023 17:35, Paulo Pavacic wrote:
> > Fannal C3004 is a 480x800 display made by fannal that requires
> > DCS initialization sequences.
> >
> > Signed-off-by: Paulo Pavacic <pavacic.p@gmail.com>
> > ---
>
> > v3 changelog:
> >  - using generic mipi_dsi_dcs_write_seq
>
> This is marked as v2?

I have ruined numbering. At first this driver was named
panel-mipi-dsi-bringup and parts of it weren't handled under patchset.

>
> >  - removed success prints
> >  - removed some comments
> >  - simplified code/removed support for different panels
> >  - changed namespace from fann to fannal
> > v2 changelog:
> >  - renamed from panel-mipi-dsi-bringup
> >  - only one MAINTAINER e-mail
> > ---
> >  MAINTAINERS
>
>
> > +static int fannal_panel_probe(struct mipi_dsi_device *dsi)
> > +{
> > +     struct device *dev = &dsi->dev;
> > +     struct fannal_panel_data *panel_data;
> > +     int ret;
> > +
> > +     panel_data = devm_kzalloc(&dsi->dev, sizeof(*panel_data), GFP_KERNEL);
> > +
> > +     if (!panel_data)
> > +             return -ENOMEM;
> > +
> > +     panel_data->reset = devm_gpiod_get_optional(
> > +             dev, "reset", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
>
> dev should be in previous line
>
> Why this is nonexclusive? How many instances of same driver are
> expecting to get this on one system?
>
> > +
> > +     if (IS_ERR(panel_data->reset)) {
> > +             ret = PTR_ERR(panel_data->reset);
> > +             dev_err(dev,
> > +                     "error: probe: get reset GPIO: (%d) Check the fdt\n",
> > +                     ret);
>
> return dev_err_probe
>
> > +             return ret;
> > +     }
> > +
> > +     mipi_dsi_set_drvdata(dsi, panel_data);
> > +
> > +     dsi->format = MIPI_DSI_FMT_RGB888;
> > +     dsi->mode_flags = MIPI_DSI_CLOCK_NON_CONTINUOUS |
> > +                       MIPI_DSI_MODE_VSYNC_FLUSH | MIPI_DSI_MODE_VIDEO_HSE |
> > +                       MIPI_DSI_MODE_NO_EOT_PACKET |
> > +                       MIPI_DSI_MODE_VIDEO_SYNC_PULSE | MIPI_DSI_MODE_VIDEO;
> > +     dsi->lanes = 2;
> > +
> > +     gpiod_set_value_cansleep(panel_data->reset, 1);
>
> So you leave the panel in reset state?
yes

> > +
> > +     drm_panel_init(&panel_data->panel, dev, &fannal_panel_funcs,
> > +                    DRM_MODE_CONNECTOR_DSI);
> > +     dev_set_drvdata(dev, panel_data);
> > +
> > +     drm_panel_add(&panel_data->panel);
> > +
> > +     ret = mipi_dsi_attach(dsi);
> > +     if (ret) {
> > +             drm_panel_remove(&panel_data->panel);
> > +             dev_err(dev, "error: probe fail: can't attach mipi_dsi!\n");
>
> No need to shout, skip exclamation mark.
>
>
> Best regards,
> Krzysztof
>

Thanks,
Paulo