[PATCH v2 1/8] Revert "drm/bridge: dw-mipi-dsi: Find the possible DSI devices"

[PATCH v2 1/8] Revert "drm/bridge: dw-mipi-dsi: Find the possible DSI devices"

[Jagan Teki]

This reverts commit c206c7faeb3263a7cc7b4de443a3877cd7a5e74b.

In order to avoid any probe ordering issues, the I2C based downstream
bridge drivers now register and attach the DSI devices at the probe
instead of doing it on drm_bridge_function.attach().

Examples of those commits are:

commit <6ef7ee48765f> ("drm/bridge: sn65dsi83: Register and attach our
DSI device at probe")
commit <d89078c37b10> ("drm/bridge: lt8912b: Register and attach our DSI
device at probe")
commit <864c49a31d6b> ("drm/bridge: adv7511: Register and attach our DSI
device at probe")

dw-mipi-dsi has panel or bridge finding code based on previous downstream
bridges, so revert the same and make the panel or bridge funding in host
attach as before.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- none

 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 +++++--------------
 1 file changed, 15 insertions(+), 43 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index 11d20b8638cd..1cc912b6e1f8 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -246,7 +246,6 @@ struct dw_mipi_dsi {
 
 	struct clk *pclk;
 
-	bool device_found;
 	unsigned int lane_mbps; /* per lane */
 	u32 channel;
 	u32 lanes;
@@ -310,37 +309,13 @@ static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
 	return readl(dsi->base + reg);
 }
 
-static int dw_mipi_dsi_panel_or_bridge(struct dw_mipi_dsi *dsi,
-				       struct device_node *node)
-{
-	struct drm_bridge *bridge;
-	struct drm_panel *panel;
-	int ret;
-
-	ret = drm_of_find_panel_or_bridge(node, 1, 0, &panel, &bridge);
-	if (ret)
-		return ret;
-
-	if (panel) {
-		bridge = drm_panel_bridge_add_typed(panel,
-						    DRM_MODE_CONNECTOR_DSI);
-		if (IS_ERR(bridge))
-			return PTR_ERR(bridge);
-	}
-
-	dsi->panel_bridge = bridge;
-
-	if (!dsi->panel_bridge)
-		return -EPROBE_DEFER;
-
-	return 0;
-}
-
 static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 				   struct mipi_dsi_device *device)
 {
 	struct dw_mipi_dsi *dsi = host_to_dsi(host);
 	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
+	struct drm_bridge *bridge;
+	struct drm_panel *panel;
 	int ret;
 
 	if (device->lanes > dsi->plat_data->max_data_lanes) {
@@ -354,14 +329,22 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
 
-	if (!dsi->device_found) {
-		ret = dw_mipi_dsi_panel_or_bridge(dsi, host->dev->of_node);
-		if (ret)
-			return ret;
+	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
+					  &panel, &bridge);
+	if (ret)
+		return ret;
 
-		dsi->device_found = true;
+	if (panel) {
+		bridge = drm_panel_bridge_add_typed(panel,
+						    DRM_MODE_CONNECTOR_DSI);
+		if (IS_ERR(bridge))
+			return PTR_ERR(bridge);
 	}
 
+	dsi->panel_bridge = bridge;
+
+	drm_bridge_add(&dsi->bridge);
+
 	if (pdata->host_ops && pdata->host_ops->attach) {
 		ret = pdata->host_ops->attach(pdata->priv_data, device);
 		if (ret < 0)
@@ -1021,16 +1004,6 @@ static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge,
 	/* Set the encoder type as caller does not know it */
 	bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
 
-	if (!dsi->device_found) {
-		int ret;
-
-		ret = dw_mipi_dsi_panel_or_bridge(dsi, dsi->dev->of_node);
-		if (ret)
-			return ret;
-
-		dsi->device_found = true;
-	}
-
 	/* Attach the panel-bridge to the dsi bridge */
 	return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge,
 				 flags);
@@ -1217,7 +1190,6 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
 #ifdef CONFIG_OF
 	dsi->bridge.of_node = pdev->dev.of_node;
 #endif
-	drm_bridge_add(&dsi->bridge);
 
 	return dsi;
 }
-- 
2.25.1

[PATCH v2 2/8] drm: bridge: nwl-dsi: Switch to devm_drm_of_get_bridge

[Jagan Teki]

devm_drm_of_get_bridge is capable of looking up the downstream
bridge and panel and trying to add a panel bridge if the panel
is found.

Replace explicit finding calls with devm_drm_of_get_bridge.

Cc: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- split the patch

 drivers/gpu/drm/bridge/nwl-dsi.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index 30aacd939dc3..c9e108a7eca2 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -916,22 +916,10 @@ static int nwl_dsi_bridge_attach(struct drm_bridge *bridge,
 {
 	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
 	struct drm_bridge *panel_bridge;
-	struct drm_panel *panel;
-	int ret;
-
-	ret = drm_of_find_panel_or_bridge(dsi->dev->of_node, 1, 0, &panel,
-					  &panel_bridge);
-	if (ret)
-		return ret;
-
-	if (panel) {
-		panel_bridge = drm_panel_bridge_add(panel);
-		if (IS_ERR(panel_bridge))
-			return PTR_ERR(panel_bridge);
-	}
 
-	if (!panel_bridge)
-		return -EPROBE_DEFER;
+	panel_bridge = devm_drm_of_get_bridge(dsi->dev, dsi->dev->of_node, 1, 0);
+	if (IS_ERR(panel_bridge))
+		return PTR_ERR(panel_bridge);
 
 	return drm_bridge_attach(bridge->encoder, panel_bridge, bridge, flags);
 }
-- 
2.25.1

Re: [PATCH v2 2/8] drm: bridge: nwl-dsi: Switch to devm_drm_of_get_bridge

[Guido Günther]

Hi,
On Tue, Mar 01, 2022 at 07:42:41PM +0530, Jagan Teki wrote:
> devm_drm_of_get_bridge is capable of looking up the downstream
> bridge and panel and trying to add a panel bridge if the panel
> is found.
> 
> Replace explicit finding calls with devm_drm_of_get_bridge.
> 
> Cc: Guido Günther <agx@sigxcpu.org>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
> Changes for v2:
> - split the patch
> 
>  drivers/gpu/drm/bridge/nwl-dsi.c | 18 +++---------------
>  1 file changed, 3 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
> index 30aacd939dc3..c9e108a7eca2 100644
> --- a/drivers/gpu/drm/bridge/nwl-dsi.c
> +++ b/drivers/gpu/drm/bridge/nwl-dsi.c
> @@ -916,22 +916,10 @@ static int nwl_dsi_bridge_attach(struct drm_bridge *bridge,
>  {
>  	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
>  	struct drm_bridge *panel_bridge;
> -	struct drm_panel *panel;
> -	int ret;
> -
> -	ret = drm_of_find_panel_or_bridge(dsi->dev->of_node, 1, 0, &panel,
> -					  &panel_bridge);
> -	if (ret)
> -		return ret;
> -
> -	if (panel) {
> -		panel_bridge = drm_panel_bridge_add(panel);
> -		if (IS_ERR(panel_bridge))
> -			return PTR_ERR(panel_bridge);
> -	}
>  
> -	if (!panel_bridge)
> -		return -EPROBE_DEFER;
> +	panel_bridge = devm_drm_of_get_bridge(dsi->dev, dsi->dev->of_node, 1, 0);
> +	if (IS_ERR(panel_bridge))
> +		return PTR_ERR(panel_bridge);
>  
>  	return drm_bridge_attach(bridge->encoder, panel_bridge, bridge, flags);
>  }

Reviewed-by: Guido Günther <agx@sigxcpu.org>

Thanks,
 -- Guido

> -- 
> 2.25.1
> 

[PATCH v2 3/8] drm: mediatek: mtk_dsi: Switch to devm_drm_of_get_bridge

[Jagan Teki]

devm_drm_of_get_bridge is capable of looking up the downstream
bridge and panel and trying to add a panel bridge if the panel
is found.

Replace explicit finding calls with devm_drm_of_get_bridge.

Cc: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- split the patch

 drivers/gpu/drm/mediatek/mtk_dsi.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..a1b3e1f4b497 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -1004,7 +1004,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 {
 	struct mtk_dsi *dsi;
 	struct device *dev = &pdev->dev;
-	struct drm_panel *panel;
 	struct resource *regs;
 	int irq_num;
 	int ret;
@@ -1021,17 +1020,10 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
-					  &panel, &dsi->next_bridge);
-	if (ret)
+	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
+	if (IS_ERR(dsi->next_bridge)) {
+		ret = PTR_ERR(dsi->next_bridge);
 		goto err_unregister_host;
-
-	if (panel) {
-		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
-		if (IS_ERR(dsi->next_bridge)) {
-			ret = PTR_ERR(dsi->next_bridge);
-			goto err_unregister_host;
-		}
 	}
 
 	dsi->driver_data = of_device_get_match_data(dev);
-- 
2.25.1

[PATCH v2 4/8] drm: bridge: dw-mipi-dsi: Switch to devm_drm_of_get_bridge

[Jagan Teki]

devm_drm_of_get_bridge is capable of looking up the downstream
bridge and panel and trying to add a panel bridge if the panel
is found.

Replace explicit finding calls with devm_drm_of_get_bridge.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- split the patch

 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index 1cc912b6e1f8..b2efecf7d160 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -315,7 +315,6 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 	struct dw_mipi_dsi *dsi = host_to_dsi(host);
 	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
 	struct drm_bridge *bridge;
-	struct drm_panel *panel;
 	int ret;
 
 	if (device->lanes > dsi->plat_data->max_data_lanes) {
@@ -329,17 +328,9 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
 
-	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
-					  &panel, &bridge);
-	if (ret)
-		return ret;
-
-	if (panel) {
-		bridge = drm_panel_bridge_add_typed(panel,
-						    DRM_MODE_CONNECTOR_DSI);
-		if (IS_ERR(bridge))
-			return PTR_ERR(bridge);
-	}
+	bridge = devm_drm_of_get_bridge(dsi->dev, dsi->dev->of_node, 1, 0);
+	if (IS_ERR(bridge))
+		return PTR_ERR(bridge);
 
 	dsi->panel_bridge = bridge;
 
-- 
2.25.1

[PATCH v2 5/8] drm: bridge: nxp-ptn3460: Switch to devm_drm_of_get_bridge

[Jagan Teki]

devm_drm_of_get_bridge is capable of looking up the downstream
bridge and panel and trying to add a panel bridge if the panel
is found.

Replace explicit finding calls with devm_drm_of_get_bridge.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- split the patch

 drivers/gpu/drm/bridge/nxp-ptn3460.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/nxp-ptn3460.c b/drivers/gpu/drm/bridge/nxp-ptn3460.c
index e941c1132598..1ab91f4e057b 100644
--- a/drivers/gpu/drm/bridge/nxp-ptn3460.c
+++ b/drivers/gpu/drm/bridge/nxp-ptn3460.c
@@ -263,7 +263,6 @@ static int ptn3460_probe(struct i2c_client *client,
 	struct device *dev = &client->dev;
 	struct ptn3460_bridge *ptn_bridge;
 	struct drm_bridge *panel_bridge;
-	struct drm_panel *panel;
 	int ret;
 
 	ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
@@ -271,11 +270,7 @@ static int ptn3460_probe(struct i2c_client *client,
 		return -ENOMEM;
 	}
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &panel, NULL);
-	if (ret)
-		return ret;
-
-	panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+	panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
 	if (IS_ERR(panel_bridge))
 		return PTR_ERR(panel_bridge);
 
-- 
2.25.1

[PATCH v2 6/8] drm: bridge: parade-ps8622: Switch to devm_drm_of_get_bridge

[Jagan Teki]

devm_drm_of_get_bridge is capable of looking up the downstream
bridge and panel and trying to add a panel bridge if the panel
is found.

Replace explicit finding calls with devm_drm_of_get_bridge.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- split the patch

 drivers/gpu/drm/bridge/parade-ps8622.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/parade-ps8622.c b/drivers/gpu/drm/bridge/parade-ps8622.c
index 614b19f0f1b7..37b308850b4e 100644
--- a/drivers/gpu/drm/bridge/parade-ps8622.c
+++ b/drivers/gpu/drm/bridge/parade-ps8622.c
@@ -452,18 +452,13 @@ static int ps8622_probe(struct i2c_client *client,
 	struct device *dev = &client->dev;
 	struct ps8622_bridge *ps8622;
 	struct drm_bridge *panel_bridge;
-	struct drm_panel *panel;
 	int ret;
 
 	ps8622 = devm_kzalloc(dev, sizeof(*ps8622), GFP_KERNEL);
 	if (!ps8622)
 		return -ENOMEM;
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &panel, NULL);
-	if (ret)
-		return ret;
-
-	panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+	panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
 	if (IS_ERR(panel_bridge))
 		return PTR_ERR(panel_bridge);
 
-- 
2.25.1

[PATCH v2 7/8] drm: bridge: anx7625: Switch to devm_drm_of_get_bridge

[Jagan Teki]

devm_drm_of_get_bridge is capable of looking up the downstream
bridge and panel and trying to add a panel bridge if the panel
is found.

Replace explicit finding calls with devm_drm_of_get_bridge.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- split the patch

 drivers/gpu/drm/bridge/analogix/anx7625.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 9aab879a8851..f7c911104464 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1606,8 +1606,6 @@ static int anx7625_parse_dt(struct device *dev,
 			    struct anx7625_platform_data *pdata)
 {
 	struct device_node *np = dev->of_node, *ep0;
-	struct drm_panel *panel;
-	int ret;
 	int bus_type, mipi_lanes;
 
 	anx7625_get_swing_setting(dev, pdata);
@@ -1644,16 +1642,7 @@ static int anx7625_parse_dt(struct device *dev,
 	if (of_property_read_bool(np, "analogix,audio-enable"))
 		pdata->audio_en = 1;
 
-	ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
-	if (ret < 0) {
-		if (ret == -ENODEV)
-			return 0;
-		return ret;
-	}
-	if (!panel)
-		return -ENODEV;
-
-	pdata->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+	pdata->panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
 	if (IS_ERR(pdata->panel_bridge))
 		return PTR_ERR(pdata->panel_bridge);
 	DRM_DEV_DEBUG_DRIVER(dev, "get panel node.\n");
-- 
2.25.1

[PATCH v2 8/8] drm: bridge: anx7625: Switch to devm_drm_of_get_bridge

[Jagan Teki]

devm_drm_of_get_bridge is capable of looking up the downstream
bridge and panel and trying to add a panel bridge if the panel
is found.

Replace explicit finding calls with devm_drm_of_get_bridge.

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- split the patch

 drivers/gpu/drm/mcde/mcde_dsi.c | 39 +++++----------------------------
 1 file changed, 5 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/mcde/mcde_dsi.c b/drivers/gpu/drm/mcde/mcde_dsi.c
index 5651734ce977..9371349b8b25 100644
--- a/drivers/gpu/drm/mcde/mcde_dsi.c
+++ b/drivers/gpu/drm/mcde/mcde_dsi.c
@@ -1073,9 +1073,7 @@ static int mcde_dsi_bind(struct device *dev, struct device *master,
 	struct drm_device *drm = data;
 	struct mcde *mcde = to_mcde(drm);
 	struct mcde_dsi *d = dev_get_drvdata(dev);
-	struct device_node *child;
-	struct drm_panel *panel = NULL;
-	struct drm_bridge *bridge = NULL;
+	struct drm_bridge *bridge;
 
 	if (!of_get_available_child_count(dev->of_node)) {
 		dev_info(dev, "unused DSI interface\n");
@@ -1100,37 +1098,10 @@ static int mcde_dsi_bind(struct device *dev, struct device *master,
 		return PTR_ERR(d->lp_clk);
 	}
 
-	/* Look for a panel as a child to this node */
-	for_each_available_child_of_node(dev->of_node, child) {
-		panel = of_drm_find_panel(child);
-		if (IS_ERR(panel)) {
-			dev_err(dev, "failed to find panel try bridge (%ld)\n",
-				PTR_ERR(panel));
-			panel = NULL;
-
-			bridge = of_drm_find_bridge(child);
-			if (!bridge) {
-				dev_err(dev, "failed to find bridge\n");
-				return -EINVAL;
-			}
-		}
-	}
-	if (panel) {
-		bridge = drm_panel_bridge_add_typed(panel,
-						    DRM_MODE_CONNECTOR_DSI);
-		if (IS_ERR(bridge)) {
-			dev_err(dev, "error adding panel bridge\n");
-			return PTR_ERR(bridge);
-		}
-		dev_info(dev, "connected to panel\n");
-		d->panel = panel;
-	} else if (bridge) {
-		/* TODO: AV8100 HDMI encoder goes here for example */
-		dev_info(dev, "connected to non-panel bridge (unsupported)\n");
-		return -ENODEV;
-	} else {
-		dev_err(dev, "no panel or bridge\n");
-		return -ENODEV;
+	bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
+	if (IS_ERR(bridge)) {
+		dev_err(dev, "error to get bridge\n");
+		return PTR_ERR(bridge);
 	}
 
 	d->bridge_out = bridge;
-- 
2.25.1

Re: [PATCH v2 8/8] drm: bridge: anx7625: Switch to devm_drm_of_get_bridge

[Linus Walleij]

On Tue, Mar 1, 2022 at 3:13 PM Jagan Teki <jagan@amarulasolutions.com> wrote:

> devm_drm_of_get_bridge is capable of looking up the downstream
> bridge and panel and trying to add a panel bridge if the panel
> is found.
>
> Replace explicit finding calls with devm_drm_of_get_bridge.
>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
> Changes for v2:
> - split the patch

This will be nice code reduction when it works!

> -       struct drm_panel *panel = NULL;
> -       struct drm_bridge *bridge = NULL;
> +       struct drm_bridge *bridge;

OK... and then you delete the code that uses panel. But:

static void mcde_dsi_unbind(struct device *dev, struct device *master,
                            void *data)
{
        struct mcde_dsi *d = dev_get_drvdata(dev);

        if (d->panel)
                drm_panel_bridge_remove(d->bridge_out);
        regmap_update_bits(d->prcmu, PRCM_DSI_SW_RESET,
                           PRCM_DSI_SW_RESET_DSI0_SW_RESETN, 0);
}

So this will not even compile.

I suppose you have a solution for removing the panel bridge automatically
as well?

Yours,
Linus Walleij

Re: [PATCH v2 8/8] drm: bridge: anx7625: Switch to devm_drm_of_get_bridge

[Jagan Teki]

On Wed, Mar 2, 2022 at 4:43 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Tue, Mar 1, 2022 at 3:13 PM Jagan Teki <jagan@amarulasolutions.com> wrote:
>
> > devm_drm_of_get_bridge is capable of looking up the downstream
> > bridge and panel and trying to add a panel bridge if the panel
> > is found.
> >
> > Replace explicit finding calls with devm_drm_of_get_bridge.
> >
> > Cc: Linus Walleij <linus.walleij@linaro.org>
> > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > ---
> > Changes for v2:
> > - split the patch
>
> This will be nice code reduction when it works!
>
> > -       struct drm_panel *panel = NULL;
> > -       struct drm_bridge *bridge = NULL;
> > +       struct drm_bridge *bridge;
>
> OK... and then you delete the code that uses panel. But:
>
> static void mcde_dsi_unbind(struct device *dev, struct device *master,
>                             void *data)
> {
>         struct mcde_dsi *d = dev_get_drvdata(dev);
>
>         if (d->panel)
>                 drm_panel_bridge_remove(d->bridge_out);

I think using drm_bridge_remove(d->bridge_out); will directly remove
the bridge whether it is the next bridge or panel bridge as bridge_out
is already found the relevant downstream.

Jagan.

Re: [PATCH v2 8/8] drm: bridge: anx7625: Switch to devm_drm_of_get_bridge

[Linus Walleij]

On Tue, Mar 1, 2022 at 3:13 PM Jagan Teki <jagan@amarulasolutions.com> wrote:

> +       bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +       if (IS_ERR(bridge)) {
> +               dev_err(dev, "error to get bridge\n");
> +               return PTR_ERR(bridge);
>         }
>
>         d->bridge_out = bridge;

Also notice how this bridge gets used in other places:

struct drm_connector *connector = drm_panel_bridge_connector(mcde->bridge);

Since you deleted:

-       } else if (bridge) {
-               /* TODO: AV8100 HDMI encoder goes here for example */
-               dev_info(dev, "connected to non-panel bridge (unsupported)\n");
-               return -ENODEV;

This will now have "interesting" effects. I think.

I don't know if there is a way to solve this though?

Yours,
Linus Walleij

Re: [PATCH v2 8/8] drm: bridge: anx7625: Switch to devm_drm_of_get_bridge

[Jagan Teki]

On Wed, Mar 2, 2022 at 4:50 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Tue, Mar 1, 2022 at 3:13 PM Jagan Teki <jagan@amarulasolutions.com> wrote:
>
> > +       bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> > +       if (IS_ERR(bridge)) {
> > +               dev_err(dev, "error to get bridge\n");
> > +               return PTR_ERR(bridge);
> >         }
> >
> >         d->bridge_out = bridge;
>
> Also notice how this bridge gets used in other places:
>
> struct drm_connector *connector = drm_panel_bridge_connector(mcde->bridge);

mcde->bridge bridge is the current bridge pointer it cannot affect
this change. d->bridge_out is what we are finding of the downstream
bridge.

>
> Since you deleted:
>
> -       } else if (bridge) {
> -               /* TODO: AV8100 HDMI encoder goes here for example */
> -               dev_info(dev, "connected to non-panel bridge (unsupported)\n");
> -               return -ENODEV;

So, this means mcde dsi can support if the downstream bridge is the
panel not if the downstream bridge is the next bridge. With
devm_drm_of_get_bridge we cannot find that diff. Identifying the
panel-bridge with some name pointer during panel_bridge_add might
solve this, not sure that is proper way to do that?

Thanks,
Jagan.

Re: [PATCH v2 8/8] drm: bridge: anx7625: Switch to devm_drm_of_get_bridge

[Linus Walleij]

On Wed, Mar 2, 2022 at 5:37 AM Jagan Teki <jagan@amarulasolutions.com> wrote:
> On Wed, Mar 2, 2022 at 4:50 AM Linus Walleij <linus.walleij@linaro.org> wrote:
> >
> > On Tue, Mar 1, 2022 at 3:13 PM Jagan Teki <jagan@amarulasolutions.com> wrote:
> >
> > > +       bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> > > +       if (IS_ERR(bridge)) {
> > > +               dev_err(dev, "error to get bridge\n");
> > > +               return PTR_ERR(bridge);
> > >         }
> > >
> > >         d->bridge_out = bridge;
> >
> > Also notice how this bridge gets used in other places:
> >
> > struct drm_connector *connector = drm_panel_bridge_connector(mcde->bridge);
>
> mcde->bridge bridge is the current bridge pointer it cannot affect
> this change. d->bridge_out is what we are finding of the downstream
> bridge.

Sorry I confused things.

Got lost in my own code :/

The bridge in the other file is for DPI obviously...
I should rename it dpi_panel_bridge.

> > Since you deleted:
> >
> > -       } else if (bridge) {
> > -               /* TODO: AV8100 HDMI encoder goes here for example */
> > -               dev_info(dev, "connected to non-panel bridge (unsupported)\n");
> > -               return -ENODEV;
>
> So, this means mcde dsi can support if the downstream bridge is the
> panel not if the downstream bridge is the next bridge. With
> devm_drm_of_get_bridge we cannot find that diff. Identifying the
> panel-bridge with some name pointer during panel_bridge_add might
> solve this, not sure that is proper way to do that?

I'd say leave it, as the DSI bridge (bridge_out) doesn't really care
about this being a panel or not. A further bridge down the chain
should "just work" (famous last words).

Just make sure we properly remove bridge_out in unbind call.

Yours,
Linus Walleij