Hi Kieran,
Thank you for the patch.
On Tue, Nov 30, 2021 at 04:25:12PM +0000, Kieran Bingham wrote:
> The bridge probe ordering for DSI devices has been clarified and further
> documented in
I've read the document and
:-)
> To support connecting with the SN65DSI86 device after commit c3b75d4734cb
> ("drm/bridge: sn65dsi86: Register and attach our DSI device at probe"),
> update to the new probe ordering to remove a perpetual -EPROBE_DEFER
> loop between the two devices.
>
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
>
> ---
> v2
> - Remove now unused panel variable from rcar_mipi_dsi_probe()
>
> drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c | 49 +++++++++++++------------
> 1 file changed, 26 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> index 50e922328fed..0a9f197ef62c 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> @@ -637,6 +637,8 @@ static int rcar_mipi_dsi_host_attach(struct mipi_dsi_host *host,
> struct mipi_dsi_device *device)
> {
> struct rcar_mipi_dsi *dsi = host_to_rcar_mipi_dsi(host);
> + struct drm_panel *panel;
> + int ret;
>
> if (device->lanes > dsi->num_data_lanes)
> return -EINVAL;
> @@ -644,12 +646,36 @@ static int rcar_mipi_dsi_host_attach(struct mipi_dsi_host *host,
> dsi->lanes = device->lanes;
> dsi->format = device->format;
>
> + ret = drm_of_find_panel_or_bridge(dsi->dev->of_node, 1, 0, &panel,
> + &dsi->next_bridge);
> + if (ret) {
> + dev_err_probe(dsi->dev, ret, "could not find next bridge\n");
dev_err_probe() should only be used in probe(), and this function isn't
guaranteed to be called at probe time only.
This isn't a big deal as the next patch fixes this, and both will be
squashed. Furthermore, rcar_mipi_dsi_host_attach() should only be called
when the DSI device gets registered, which should happen after it
registers its bridge, so I don't think we can see a probe deferral here.
Other than that the patch looks fine, I'll squash it with the DSI
driver.
> + return ret;
> + }
> +
> + if (!dsi->next_bridge) {
> + dsi->next_bridge = devm_drm_panel_bridge_add(dsi->dev, panel);
> + if (IS_ERR(dsi->next_bridge)) {
> + dev_err(dsi->dev, "failed to create panel bridge\n");
> + return PTR_ERR(dsi->next_bridge);
> + }
> + }
> +
> + /* Initialize the DRM bridge. */
> + dsi->bridge.funcs = &rcar_mipi_dsi_bridge_ops;
> + dsi->bridge.of_node = dsi->dev->of_node;
> + drm_bridge_add(&dsi->bridge);
> +
> return 0;
> }
>
> static int rcar_mipi_dsi_host_detach(struct mipi_dsi_host *host,
> struct mipi_dsi_device *device)
> {
> + struct rcar_mipi_dsi *dsi = host_to_rcar_mipi_dsi(host);
> +
> + drm_bridge_remove(&dsi->bridge);
> +
> return 0;
> }
>
> @@ -731,7 +757,6 @@ static int rcar_mipi_dsi_get_clocks(struct rcar_mipi_dsi *dsi)
> static int rcar_mipi_dsi_probe(struct platform_device *pdev)
> {
> struct rcar_mipi_dsi *dsi;
> - struct drm_panel *panel;
> struct resource *mem;
> int ret;
>
> @@ -764,21 +789,6 @@ static int rcar_mipi_dsi_probe(struct platform_device *pdev)
> return PTR_ERR(dsi->rstc);
> }
>
> - ret = drm_of_find_panel_or_bridge(dsi->dev->of_node, 1, 0, &panel,
> - &dsi->next_bridge);
> - if (ret) {
> - dev_err_probe(dsi->dev, ret, "could not find next bridge\n");
> - return ret;
> - }
> -
> - if (!dsi->next_bridge) {
> - dsi->next_bridge = devm_drm_panel_bridge_add(dsi->dev, panel);
> - if (IS_ERR(dsi->next_bridge)) {
> - dev_err(dsi->dev, "failed to create panel bridge\n");
> - return PTR_ERR(dsi->next_bridge);
> - }
> - }
> -
> /* Initialize the DSI host. */
> dsi->host.dev = dsi->dev;
> dsi->host.ops = &rcar_mipi_dsi_host_ops;
> @@ -786,11 +796,6 @@ static int rcar_mipi_dsi_probe(struct platform_device *pdev)
> if (ret < 0)
> return ret;
>
> - /* Initialize the DRM bridge. */
> - dsi->bridge.funcs = &rcar_mipi_dsi_bridge_ops;
> - dsi->bridge.of_node = dsi->dev->of_node;
> - drm_bridge_add(&dsi->bridge);
> -
> return 0;
> }
>
> @@ -798,8 +803,6 @@ static int rcar_mipi_dsi_remove(struct platform_device *pdev)
> {
> struct rcar_mipi_dsi *dsi = platform_get_drvdata(pdev);
>
> - drm_bridge_remove(&dsi->bridge);
> -
> mipi_dsi_host_unregister(&dsi->host);
>
> return 0;
--
Regards,
Laurent Pinchart
