Re: 答复: [PATCH v2 6/6] drm/panel: Add Ilitek ILI9341 DBI panel driver

[Paul Cercueil]

Hi Leon,

Le dim. 30 août 2020 à 16:36, 何小龙 (Leon He) 
<Leon.He@xxxxxxxxxx> a écrit :
> >  +struct ili9341 {
> >  +       struct drm_panel panel;
> >  +       struct mipi_dsi_device *dsi;
> >  +       const struct ili9341_pdata *pdata;
> >  +
> >  +       struct gpio_desc        *reset_gpiod;
> >  +       u32 rotation;
> >  +};
> >  +
>
> Hi Paul, you put the mipi_dsi_device inside the struct. I think it 
> maybe not
> a good idea. That means the panel has a MIPI-DSI interface but it 
> doesn't
> have actually.
>
> >  +static int ili9341_probe(struct mipi_dsi_device *dsi)
> >  +{
> >  +       struct device *dev = &dsi->dev;
> >  +       struct ili9341 *priv;
> >  +       int ret;
> >  +
> >  +       /* See comment for mipi_dbi_spi_init() */
> >  +       if (!dev->coherent_dma_mask) {
> >  +               ret = dma_coerce_mask_and_coherent(dev, 
> > DMA_BIT_MASK(32));
> >  +               if (ret) {
> >  +                       dev_warn(dev, "Failed to set dma mask 
> > %d\n", ret);
> >  +                       return ret;
> >  +               }
> >  +       }
> >  +
> >  +       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> >  +       if (!priv)
> >  +               return -ENOMEM;
> >  +
> >  +       mipi_dsi_set_drvdata(dsi, priv);
> >  +       priv->dsi = dsi;
> >  +
> >  +       device_property_read_u32(dev, "rotation", &priv->rotation);
> >  +
> >  +       priv->pdata = device_get_match_data(dev);
> >  +       if (!priv->pdata)
> >  +               return -EINVAL;
> >  +
> >  +       drm_panel_init(&priv->panel, dev, &ili9341_funcs,
> >  +                      DRM_MODE_CONNECTOR_DPI);
> >  +
> >  +       priv->reset_gpiod = devm_gpiod_get(dev, "reset", 
> > GPIOD_OUT_HIGH);
> >  +       if (IS_ERR(priv->reset_gpiod)) {
> >  +               dev_err(dev, "Couldn't get our reset GPIO\n");
> >  +               return PTR_ERR(priv->reset_gpiod);
> >  +       }
> >  +
> >  +       ret = drm_panel_of_backlight(&priv->panel);
> >  +       if (ret < 0) {
> >  +               if (ret != -EPROBE_DEFER)
> >  +                       dev_err(dev, "Failed to get backlight 
> > handle\n");
> >  +               return ret;
> >  +       }
> >  +
> >  +       drm_panel_add(&priv->panel);
> >  +
> >  +       dsi->bus_type = priv->pdata->bus_type;
> >  +       dsi->lanes = priv->pdata->lanes;
> >  +       dsi->format = MIPI_DSI_FMT_RGB565;
> >  +
> >  +       ret = mipi_dsi_attach(dsi);
> >  +       if (ret) {
> >  +               dev_err(dev, "Failed to attach DSI panel\n");
> >  +               goto err_panel_remove;
> >  +       }
> >  +
> >  +       ret = mipi_dsi_maybe_register_tiny_driver(dsi);
> >  +       if (ret) {
> >  +               dev_err(dev, "Failed to init TinyDRM driver\n");
> >  +               goto err_mipi_dsi_detach;
> >  +       }
> >  +
> >  +       return 0;
> >  +
> >  +err_mipi_dsi_detach:
> >  +       mipi_dsi_detach(dsi);
> >  +err_panel_remove:
> >  +       drm_panel_remove(&priv->panel);
> >  +       return ret;
> >  +}
> >  +
> >  +static int ili9341_remove(struct mipi_dsi_device *dsi)
> >  +{
> >  +       struct ili9341 *priv = mipi_dsi_get_drvdata(dsi);
> >  +
> >  +       mipi_dsi_detach(dsi);
> >  +       drm_panel_remove(&priv->panel);
> >  +
> >  +       drm_panel_disable(&priv->panel);
> >  +       drm_panel_unprepare(&priv->panel);
> >  +
> >  +       return 0;
> >  +}
> >  +
> >  +static const struct ili9341_pdata yx240qv29_pdata = {
> >  +       .mode = { DRM_SIMPLE_MODE(240, 320, 37, 49) },
> >  +       .width_mm = 0, // TODO
> >  +       .height_mm = 0, // TODO
> >  +       .bus_type = MIPI_DCS_BUS_TYPE_DBI_SPI_C3,
> >  +       .lanes = 1,
> >  +};
> >  +
> >  +static const struct of_device_id ili9341_of_match[] = {
> >  +       { .compatible = "adafruit,yx240qv29", .data = 
> > &yx240qv29_pdata },
> >  +       { }
> >  +};
> >  +MODULE_DEVICE_TABLE(of, ili9341_of_match);
> >  +
> >  +static struct mipi_dsi_driver ili9341_dsi_driver = {
> >  +       .probe          = ili9341_probe,
> >  +       .remove         = ili9341_remove,
> >  +       .driver = {
> >  +               .name           = "ili9341-dsi",
> >  +               .of_match_table = ili9341_of_match,
> >  +       },
> >  +};
> >  +module_mipi_dsi_driver(ili9341_dsi_driver);
>
> Again, you treat this driver as a mipi dsi driver but for a MIPI-DBI 
> (I8080/SPI)
> panel device. That will make developers confused.
>
> Is it possible to just add a mipi_dbi_driver for I8080/SPI interface 
> panel?
> Thanks!

Please read the cover letter, it explains why it's done this way. The 
whole point of this patchset is to merge DSI and DBI frameworks in a 
way that can be maintained.

Cheers,
-Paul