Hello Marco, Liu,
On Tue Jan 13, 2026 at 8:07 PM CET, Marco Felsch wrote:
> From: Liu Ying <[email protected]>
>
> NXP i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register which
> configures parallel display format by using the "PARALLEL_DISP_FORMAT"
> field. Add a DRM bridge driver to support the display format configuration.
>
> Signed-off-by: Liu Ying <[email protected]>
> [[email protected]: port to v6.19-rc1]
> [[email protected]: add review feedback (Alexander)]
> [[email protected]: fix to short Kconfig description (checkpath)]
> [[email protected]: use "GPL" instead of "GPL v2" (checkpatch)]
> [[email protected]: add bus-width support]
> Signed-off-by: Marco Felsch <[email protected]>
I'm sorry to be reviewing at v8 only, I hadn't noticed this series before.
> ---
> drivers/gpu/drm/bridge/imx/Kconfig | 11 ++
> drivers/gpu/drm/bridge/imx/Makefile | 1 +
> drivers/gpu/drm/bridge/imx/imx93-pdfc.c | 221
> ++++++++++++++++++++++++++++++++
> 3 files changed, 233 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/imx/Kconfig
> b/drivers/gpu/drm/bridge/imx/Kconfig
> index
> b9028a5e5a065c3237b404111d8df57e8e017f9d..181ee87bc0f9f65ee0b6e5edbb48ba808dfbb71f
> 100644
> --- a/drivers/gpu/drm/bridge/imx/Kconfig
> +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> @@ -99,4 +99,15 @@ config DRM_IMX93_MIPI_DSI
> Choose this to enable MIPI DSI controller found in Freescale i.MX93
> processor.
>
> +config DRM_IMX93_PARALLEL_DISP_FMT_CONFIG
> + tristate "NXP i.MX91/i.MX93 parallel display format configuration"
Minor nit: this is a driver for a device, so calling it "configuration"
seems weird. From the code it looks like a device converting the color
format, so what about "NXP i.MX91/i.MX93 parallel display format
converter"?
[...]
> +static int imx93_pdfc_bridge_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct imx93_pdfc *pdfc;
> + struct device_node *ep;
> + int err;
> +
> + pdfc = devm_drm_bridge_alloc(dev, struct imx93_pdfc, bridge, &funcs);
> + if (IS_ERR(pdfc))
> + return PTR_ERR(pdfc);
> +
> + pdfc->regmap = syscon_node_to_regmap(dev->of_node->parent);
> + if (IS_ERR(pdfc->regmap))
> + return dev_err_probe(dev, PTR_ERR(pdfc->regmap),
> + "failed to get regmap\n");
> +
> + /* No limits per default */
> + pdfc->phy_bus_width = 24;
> +
> + /* Get output ep (port1/endpoint) */
> + ep = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
> + if (ep) {
> + err = of_property_read_u32(ep, "bus-width",
> &pdfc->phy_bus_width);
> + of_node_put(ep);
> +
> + /* bus-width is optional but it must have valid data if present
> */
> + if (err && err != -EINVAL)
> + return dev_err_probe(dev, err,
> + "failed to query bus-width\n");
> + }
> +
> + pdfc->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
> + if (IS_ERR(pdfc->next_bridge))
> + return dev_err_probe(dev, PTR_ERR(pdfc->next_bridge),
> + "failed to get next bridge\n");
> +
> + pdfc->dev = dev;
> + pdfc->bridge.driver_private = pdfc;
pdfc embeds the struct drm_bridge, which is the mandatory design since
devm_drm_bridge_alloc() got added, so driver_private shouldn't be needed
anymore. Most drivers have a bridge_to_foo() inline function using
component_of() to get the private struct from the drm_bridge pointer,
e.g. [0] and [1].
[0]
https://elixir.bootlin.com/linux/v6.18.5/source/drivers/gpu/drm/bridge/simple-bridge.c#L39-L43
[1]
https://elixir.bootlin.com/linux/v6.18.5/source/drivers/gpu/drm/bridge/ti-sn65dsi83.c#L287-L290
A short discussion took place a few months ago about driver_private, kind
of suggesting it might be removed after all drivers have switched to
devm_drm_bridge_alloc(). I think we should at least not introduce new users
of driver_private at least.
Best regards,
Luca
--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
