On 22/01/2024 09:29, Dharma Balasubiramani wrote:
> Add a new LVDS controller driver for sam9x7 which does the following:
> - Prepares and enables the LVDS Peripheral clock
> - Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
> to the global bridge list.
> - Identifies its output endpoint as panel and adds it to the encoder
> display pipeline
> - Enables the LVDS serializer
>
> Signed-off-by: Manikandan Muralidharan <manikanda...@microchip.com>
> Signed-off-by: Dharma Balasubiramani <dharm...@microchip.com>
> ---
...
> +
> +static int mchp_lvds_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mchp_lvds *lvds;
> + struct resource *res;
> + struct device_node *port;
> + int ret;
> +
> + if (!dev->of_node)
> + return -ENODEV;
> +
> + lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
> + if (!lvds)
> + return -ENOMEM;
> +
> + lvds->dev = dev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + lvds->regs = devm_ioremap_resource(lvds->dev, res);
Why not combining these two?
> + if (IS_ERR(lvds->regs))
> + return PTR_ERR(lvds->regs);
> +
> + lvds->pclk = devm_clk_get(lvds->dev, "pclk");
> + if (IS_ERR(lvds->pclk)) {
> + DRM_DEV_ERROR(lvds->dev, "could not get pclk_lvds\n");
Handle properly deferred probe. What's DRM wrapper over dev_err_probe()?
> + return PTR_ERR(lvds->pclk);
> + }
> +
> + ret = clk_prepare(lvds->pclk);
> + if (ret < 0) {
> + DRM_DEV_ERROR(lvds->dev, "failed to prepare pclk_lvds\n");
> + return ret;
> + }
> +
> + port = of_graph_get_remote_node(dev->of_node, 1, 0);
> + if (!port) {
> + DRM_DEV_ERROR(dev,
> + "can't find port point, please init lvds panel
> port!\n");
> + return -EINVAL;
> + }
> +
> + lvds->panel = of_drm_find_panel(port);
> + of_node_put(port);
> +
> + if (IS_ERR(lvds->panel)) {
> + DRM_DEV_ERROR(dev, "failed to find panel node\n");
> + return -EPROBE_DEFER;
OK, that's for sure wrong. Don't print anything on deferred probe.
> + }
> +
> + lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
> +
> + if (IS_ERR(lvds->panel_bridge))
> + return PTR_ERR(lvds->panel_bridge);
> +
> + lvds->bridge.of_node = dev->of_node;
> + lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
> + lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
> +
> + dev_set_drvdata(dev, lvds);
> + pm_runtime_enable(dev);
> +
> + drm_bridge_add(&lvds->bridge);
> +
> + return 0;
> +}
> +
> +static int mchp_lvds_remove(struct platform_device *pdev)
> +{
> + struct mchp_lvds *lvds = platform_get_drvdata(pdev);
> +
> + pm_runtime_disable(&pdev->dev);
> + clk_unprepare(lvds->pclk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id mchp_lvds_dt_ids[] = {
> + {
> + .compatible = "microchip,sam9x7-lvds",
> + },
> + {},
> +};
> +
> +struct platform_driver mchp_lvds_driver = {
> + .probe = mchp_lvds_probe,
> + .remove = mchp_lvds_remove,
> + .driver = {
> + .name = "microchip-lvds",
> + .of_match_table = mchp_lvds_dt_ids,
> + },
> +};
> +module_platform_driver(mchp_lvds_driver);
> +
> +MODULE_AUTHOR("Manikandan Muralidharan <manikanda...@microchip.com>");
> +MODULE_AUTHOR("Dharma Balasubiramani <dharm...@microchip.com>");
> +MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:microchip-lvds");
You should not need MODULE_ALIAS() in normal cases. If you need it,
usually it means your device ID table is wrong (e.g. misses either
entries or MODULE_DEVICE_TABLE()). MODULE_ALIAS() is not a substitute
for incomplete ID table.
Best regards,
Krzysztof
