Quoting Laurent Pinchart (2021-12-01 04:38:46)

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

Good, I'm glad you've fully got the

:-)

Sorry, not sure how I missed that, I must have failed to paste in the link to the DSI probe documentation. But as you've read that, and now this is squashed, I think this is done anyway.

Thanks for handling the integrations.

-- Kieran

...

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@ideasonboard.com

---

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

Hi Laurent,

Quoting Kieran Bingham (2021-11-30 16:25:13)

Instead of open coding the calls for drm_of_find_panel_or_bridge() devm_drm_panel_bridge_add()

use the devm_drm_of_get_bridge() helper directly.

Signed-off-by: Kieran Bingham kieran.bingham+renesas@ideasonboard.com

v2:

• New patch

drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c index 0a9f197ef62c..1dfe20d3d0f2 100644 --- a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c +++ b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c @@ -637,7 +637,7 @@ 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;
  

•   struct device *dev = dsi->dev;
    int ret;
  
    if (device->lanes > dsi->num_data_lanes)
  

@@ -646,20 +646,9 @@ 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");
  

•           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);
  

•           }
  

•   }
  

•   dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
  

•   if (IS_ERR(dsi->next_bridge))
  

•           return PTR_ERR(dsi->next_bridge);
  

I did make a change here to make this:

dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0); if (IS_ERR(dsi->next_bridge)) { dev_err(dev, "failed to get next bridge\n"); return PTR_ERR(dsi->next_bridge); }

But it seems I got out of sequence and saved out the wrong patch ;-(

If you think it's better with the error print, please add it while squashing, or if you really need, I can send an updated patch and retest.

-- Kieran

    /* Initialize the DRM bridge. */
    dsi->bridge.funcs = &rcar_mipi_dsi_bridge_ops;

-- 2.30.2