Re: [PATCH v6 09/26] drm/bridge: move devm_drm_of_get_bridge and drmm_of_get_bridge to drm_bridge.c

Dmitry Baryshkov
2025-02-07T02:52:26Z

On Thu, Feb 06, 2025 at 07:14:24PM +0100, Luca Ceresoli wrote:
> devm_drm_of_get_bridge() and drmm_of_get_bridge() do not have anything to
> do with struct drm_panel anymore, they just manage bridges. So move them
> from bridge/panel.c to drm_bridge.c.
>
> Move also of_drm_find_bridge_by_endpoint() which is used only by
> devm_drm_of_get_bridge() and drmm_of_get_bridge().
>
> No code changes, only move functions to a different file within the same
> module and add an #include as needed.
>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
>
> ---
>
> This patch was added in v6.
> ---
> drivers/gpu/drm/bridge/panel.c | 102 -----------------------------------------
> drivers/gpu/drm/drm_bridge.c | 100 ++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 100 insertions(+), 102 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
> index 6995de605e7317dd1eb153afd475746ced764712..1230ae50b2020e7a9306cac83009dd600dd61d26 100644
> --- a/drivers/gpu/drm/bridge/panel.c
> +++ b/drivers/gpu/drm/bridge/panel.c
> @@ -418,49 +418,6 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
> }
> EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
>
> -/**
> - * of_drm_find_bridge_by_endpoint - return drm_bridge connected to an endpoint
> - * @np: device tree node containing encoder output ports
> - * @port: port in the device tree node
> - * @endpoint: endpoint in the device tree node
> - * @bridge: pointer to hold returned drm_bridge (must not be NULL)
> - *
> - * Given a DT node's port and endpoint number, find the connected node and
> - * return the associated struct drm_bridge.
> - *
> - * Returns zero if successful, or one of the standard error codes if it fails.
> - */
> -static int of_drm_find_bridge_by_endpoint(const struct device_node *np,
> - int port, int endpoint,
> - struct drm_bridge **bridge)

I'd say make this function the main API instead (and name it drm_of
rather than of_drm, this can happen in the previous patch).

> -{
> - int ret = -EPROBE_DEFER;
> - struct device_node *remote;
> -
> - if (!bridge)
> - return -EINVAL;
> -
> - /*
> - * of_graph_get_remote_node() produces a noisy error message if port
> - * node isn't found and the absence of the port is a legit case here,
> - * so at first we silently check whether graph presents in the
> - * device-tree node.
> - */
> - if (!of_graph_is_present(np))
> - return -ENODEV;
> -
> - remote = of_graph_get_remote_node(np, port, endpoint);
> - if (!remote)
> - return -ENODEV;
> -
> - *bridge = of_drm_find_bridge(remote);
> - if (*bridge)
> - ret = 0;
> -
> - of_node_put(remote);
> - return ret;
> -}
> -
> /**
> * of_drm_get_panel_orientation - look up the orientation of the panel through
> * the "rotation" binding from a device tree node
> @@ -1150,62 +1107,3 @@ struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge)
> return &panel_bridge->connector;
> }
> EXPORT_SYMBOL(drm_panel_bridge_connector);
> -
> -#ifdef CONFIG_OF
> -/**
> - * devm_drm_of_get_bridge - Return next bridge in the chain
> - * @dev: device to tie the bridge lifetime to
> - * @np: device tree node containing encoder output ports
> - * @port: port in the device tree node
> - * @endpoint: endpoint in the device tree node
> - *
> - * Given a DT node's port and endpoint number, finds the connected node
> - * and returns the associated bridge if any.
> - *
> - * Returns a pointer to the bridge if successful, or an error pointer
> - * otherwise.
> - */
> -struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
> - struct device_node *np,
> - u32 port, u32 endpoint)
> -{
> - struct drm_bridge *bridge;
> - int ret;
> -
> - ret = of_drm_find_bridge_by_endpoint(np, port, endpoint, &bridge);
> - if (ret)
> - return ERR_PTR(ret);
> -
> - return bridge;
> -}

Then these two functions can go into the header as static inlines with
the proper deprecation notification. There is little point in having
them in the source file. I think eventually all users should be
converted into using your new of_drm_find_bridge_by_endpoint() funcion.

> -EXPORT_SYMBOL(devm_drm_of_get_bridge);
> -
> -/**
> - * drmm_of_get_bridge - Return next bridge in the chain
> - * @drm: device to tie the bridge lifetime to
> - * @np: device tree node containing encoder output ports
> - * @port: port in the device tree node
> - * @endpoint: endpoint in the device tree node
> - *
> - * Given a DT node's port and endpoint number, finds the connected node
> - * and returns the associated bridge if any.
> - *
> - * Returns a drmm managed pointer to the bridge if successful, or an error
> - * pointer otherwise.
> - */
> -struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
> - struct device_node *np,
> - u32 port, u32 endpoint)
> -{
> - struct drm_bridge *bridge;
> - int ret;
> -
> - ret = of_drm_find_bridge_by_endpoint(np, port, endpoint, &bridge);
> - if (ret)
> - return ERR_PTR(ret);
> -
> - return bridge;
> -}
> -EXPORT_SYMBOL(drmm_of_get_bridge);
> -
> -#endif
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 87cebec2de806781cee22da54d666eee9bde3648..2aa17fbe538b86066c4e68f0d0e8046e9ca9b965 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -25,6 +25,7 @@
> #include <linux/media-bus-format.h>
> #include <linux/module.h>
> #include <linux/mutex.h>
> +#include <linux/of.h>
>
> #include <drm/drm_atomic_state_helper.h>
> #include <drm/drm_bridge.h>
> @@ -1334,6 +1335,105 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
> return NULL;
> }
> EXPORT_SYMBOL(of_drm_find_bridge);
> +
> +/**
> + * of_drm_find_bridge_by_endpoint - return drm_bridge connected to an endpoint
> + * @np: device tree node containing encoder output ports
> + * @port: port in the device tree node
> + * @endpoint: endpoint in the device tree node
> + * @bridge: pointer to hold returned drm_bridge (must not be NULL)
> + *
> + * Given a DT node's port and endpoint number, find the connected node and
> + * return the associated struct drm_bridge.
> + *
> + * Returns zero if successful, or one of the standard error codes if it fails.
> + */
> +static int of_drm_find_bridge_by_endpoint(const struct device_node *np,
> + int port, int endpoint,
> + struct drm_bridge **bridge)
> +{
> + int ret = -EPROBE_DEFER;
> + struct device_node *remote;
> +
> + if (!bridge)
> + return -EINVAL;
> +
> + /*
> + * of_graph_get_remote_node() produces a noisy error message if port
> + * node isn't found and the absence of the port is a legit case here,
> + * so at first we silently check whether graph presents in the
> + * device-tree node.
> + */
> + if (!of_graph_is_present(np))
> + return -ENODEV;
> +
> + remote = of_graph_get_remote_node(np, port, endpoint);
> + if (!remote)
> + return -ENODEV;
> +
> + *bridge = of_drm_find_bridge(remote);
> + if (*bridge)
> + ret = 0;
> +
> + of_node_put(remote);
> + return ret;
> +}
> +
> +/**
> + * devm_drm_of_get_bridge - Return next bridge in the chain
> + * @dev: device to tie the bridge lifetime to
> + * @np: device tree node containing encoder output ports
> + * @port: port in the device tree node
> + * @endpoint: endpoint in the device tree node
> + *
> + * Given a DT node's port and endpoint number, finds the connected node
> + * and returns the associated bridge if any.
> + *
> + * Returns a pointer to the bridge if successful, or an error pointer
> + * otherwise.
> + */
> +struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
> + struct device_node *np,
> + u32 port, u32 endpoint)
> +{
> + struct drm_bridge *bridge;
> + int ret;
> +
> + ret = of_drm_find_bridge_by_endpoint(np, port, endpoint, &bridge);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + return bridge;
> +}
> +EXPORT_SYMBOL(devm_drm_of_get_bridge);
> +
> +/**
> + * drmm_of_get_bridge - Return next bridge in the chain
> + * @drm: device to tie the bridge lifetime to
> + * @np: device tree node containing encoder output ports
> + * @port: port in the device tree node
> + * @endpoint: endpoint in the device tree node
> + *
> + * Given a DT node's port and endpoint number, finds the connected node
> + * and returns the associated bridge if any.
> + *
> + * Returns a drmm managed pointer to the bridge if successful, or an error
> + * pointer otherwise.
> + */
> +struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
> + struct device_node *np,
> + u32 port, u32 endpoint)
> +{
> + struct drm_bridge *bridge;
> + int ret;
> +
> + ret = of_drm_find_bridge_by_endpoint(np, port, endpoint, &bridge);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + return bridge;
> +}
> +EXPORT_SYMBOL(drmm_of_get_bridge);
> #endif
>
> MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
>
> --
> 2.34.1
>

--
With best wishes
Dmitry