drm/msm currently relies on phandles/child nodes to get data about connected panels to LVDS and DSI. This method has known limitations.
Use device graphs in DT to represent the connections between the encoder outputs and the panels. Use of_graph helpers in the driver to get the panel device node.
The usage of device graphs should also simplify management in dual dsi mode. I haven't tried this out yet, though.
changes in v2:
- Fix usage of of_node_put()
Archit Taneja (3): drm/msm: dsi host: add missing of_node_put() drm/msm: dsi host: Use device graph parsing to parse connected panel drm/msm: mdp4 lvds: get panel node via of graph parsing
Documentation/devicetree/bindings/drm/msm/dsi.txt | 15 ++++++ drivers/gpu/drm/msm/dsi/dsi_host.c | 62 ++++++++++++++++++----- drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c | 33 ++++++++---- drivers/gpu/drm/msm/msm_drv.h | 1 + 4 files changed, 88 insertions(+), 23 deletions(-)
Decrement device node refcount if of_get_child_by_name is successfully called.
Signed-off-by: Archit Taneja architt@codeaurora.org --- drivers/gpu/drm/msm/dsi/dsi_host.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index 984f9ef..5c3e82d 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -1586,8 +1586,12 @@ int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer) node = of_get_child_by_name(msm_host->pdev->dev.of_node, "panel"); if (node) { - if (!of_drm_find_panel(node)) + if (!of_drm_find_panel(node)) { + of_node_put(node); return -EPROBE_DEFER; + } + + of_node_put(node); } } }
The dsi host looks for the connected panel node by parsing for a child named 'panel'. This hierarchy isn't very flexible. The connected panel is forced to be a child to the dsi host, and hence, a mipi dsi device. This isn't suitable for dsi devices that don't use mipi dsi as their control bus.
Follow the of_graph approach of creating ports and endpoints to represent the connections between the dsi host and the panel connected to it. In our case, the dsi host will only have one output port, linked to the panel's input port.
Update DT binding documentation with device graph usage info.
Signed-off-by: Archit Taneja architt@codeaurora.org --- Documentation/devicetree/bindings/drm/msm/dsi.txt | 15 ++++++ drivers/gpu/drm/msm/dsi/dsi_host.c | 66 ++++++++++++++++------- 2 files changed, 63 insertions(+), 18 deletions(-)
diff --git a/Documentation/devicetree/bindings/drm/msm/dsi.txt b/Documentation/devicetree/bindings/drm/msm/dsi.txt index 6ccd860..c88ec3c 100644 --- a/Documentation/devicetree/bindings/drm/msm/dsi.txt +++ b/Documentation/devicetree/bindings/drm/msm/dsi.txt @@ -25,6 +25,9 @@ Required properties: - vddio-supply: phandle to vdd-io regulator device node - vdda-supply: phandle to vdda regulator device node - qcom,dsi-phy: phandle to DSI PHY device node +- port: DSI controller output port. This contains one endpoint subnode, with its + remote-endpoint set to the phandle of the connected panel's endpoint. + See Documentation/devicetree/bindings/graph.txt for device graph info.
Optional properties: - panel@0: Node of panel connected to this DSI controller. @@ -101,6 +104,18 @@ Example:
power-supply = <...>; backlight = <...>; + + port { + panel_in: endpoint { + remote-endpoint = <&dsi0_out>; + }; + }; + }; + + port { + dsi0_out: endpoint { + remote-endpoint = <&panel_in>; + }; }; };
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index 5c3e82d..5b9077d 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -20,6 +20,7 @@ #include <linux/of_device.h> #include <linux/of_gpio.h> #include <linux/of_irq.h> +#include <linux/of_graph.h> #include <linux/regulator/consumer.h> #include <linux/spinlock.h> #include <video/mipi_display.h> @@ -1383,7 +1384,7 @@ static int dsi_host_attach(struct mipi_dsi_host *host, msm_host->format = dsi->format; msm_host->mode_flags = dsi->mode_flags;
- msm_host->panel_node = dsi->dev.of_node; + WARN_ON(dsi->dev.of_node != msm_host->panel_node);
/* Some gpios defined in panel DT need to be controlled by host */ ret = dsi_host_init_panel_gpios(msm_host, &dsi->dev); @@ -1433,6 +1434,46 @@ static struct mipi_dsi_host_ops dsi_host_ops = { .transfer = dsi_host_transfer, };
+static int msm_dsi_host_parse_dt(struct msm_dsi_host *msm_host) +{ + struct device *dev = &msm_host->pdev->dev; + struct device_node *np = dev->of_node; + struct device_node *endpoint, *panel_node; + int ret; + + ret = of_property_read_u32(np, "qcom,dsi-host-index", &msm_host->id); + if (ret) { + dev_err(dev, "%s: host index not specified, ret=%d\n", + __func__, ret); + return ret; + } + + /* + * get the first endpoint node. in our case, dsi has one output port + * to which the panel is connected. + */ + endpoint = of_graph_get_next_endpoint(np, NULL); + if (IS_ERR(endpoint)) { + dev_err(dev, "%s: no valid endpoint\n", __func__); + return PTR_ERR(endpoint); + } + + /* get panel node from the output port's endpoint data */ + panel_node = of_graph_get_remote_port_parent(endpoint); + if (IS_ERR(panel_node)) { + dev_err(dev, "%s: no valid device\n", __func__); + of_node_put(endpoint); + return PTR_ERR(panel_node); + } + + of_node_put(endpoint); + of_node_put(panel_node); + + msm_host->panel_node = panel_node; + + return 0; +} + int msm_dsi_host_init(struct msm_dsi *msm_dsi) { struct msm_dsi_host *msm_host = NULL; @@ -1447,15 +1488,13 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi) goto fail; }
- ret = of_property_read_u32(pdev->dev.of_node, - "qcom,dsi-host-index", &msm_host->id); + msm_host->pdev = pdev; + + ret = msm_dsi_host_parse_dt(msm_host); if (ret) { - dev_err(&pdev->dev, - "%s: host index not specified, ret=%d\n", - __func__, ret); + pr_err("%s: failed to parse dt\n", __func__); goto fail; } - msm_host->pdev = pdev;
ret = dsi_clk_init(msm_host); if (ret) { @@ -1563,7 +1602,6 @@ int msm_dsi_host_modeset_init(struct mipi_dsi_host *host, int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer) { struct msm_dsi_host *msm_host = to_msm_dsi_host(host); - struct device_node *node; int ret;
/* Register mipi dsi host */ @@ -1583,16 +1621,8 @@ int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer) * create framebuffer. */ if (check_defer) { - node = of_get_child_by_name(msm_host->pdev->dev.of_node, - "panel"); - if (node) { - if (!of_drm_find_panel(node)) { - of_node_put(node); - return -EPROBE_DEFER; - } - - of_node_put(node); - } + if (!of_drm_find_panel(msm_host->panel_node)) + return -EPROBE_DEFER; } }
We currently get the output connected to LVDS by looking for a phandle called 'qcom,lvds-panel' under the mdp DT node.
Use the more standard of_graph approach to create an lvds output port, and retrieve the panel node from the port's endpoint data.
Signed-off-by: Archit Taneja architt@codeaurora.org --- drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c | 33 ++++++++++++++++++++++++--------- drivers/gpu/drm/msm/msm_drv.h | 1 + 2 files changed, 25 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c index 531e4ac..1bb9d8b 100644 --- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c +++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c @@ -241,22 +241,37 @@ int mdp4_enable(struct mdp4_kms *mdp4_kms) }
#ifdef CONFIG_OF -static struct drm_panel *detect_panel(struct drm_device *dev, const char *name) +static struct drm_panel *detect_panel(struct drm_device *dev) { - struct device_node *n; + struct device_node *endpoint, *panel_node; + struct device_node *np = dev->dev->of_node; struct drm_panel *panel = NULL;
- n = of_parse_phandle(dev->dev->of_node, name, 0); - if (n) { - panel = of_drm_find_panel(n); - if (!panel) - panel = ERR_PTR(-EPROBE_DEFER); + endpoint = of_graph_get_next_endpoint(np, NULL); + if (IS_ERR(endpoint)) { + dev_err(dev->dev, "no valid endpoint\n"); + return ERR_CAST(endpoint); + } + + panel_node = of_graph_get_remote_port_parent(endpoint); + if (IS_ERR(panel_node)) { + dev_err(dev->dev, "no valid panel node\n"); + of_node_put(endpoint); + return ERR_CAST(panel_node); + } + + of_node_put(endpoint); + + panel = of_drm_find_panel(panel_node); + if (IS_ERR(panel)) { + of_node_put(panel_node); + return ERR_PTR(-EPROBE_DEFER); }
return panel; } #else -static struct drm_panel *detect_panel(struct drm_device *dev, const char *name) +static struct drm_panel *detect_panel(struct drm_device *dev) { // ??? maybe use a module param to specify which panel is attached? } @@ -294,7 +309,7 @@ static int modeset_init(struct mdp4_kms *mdp4_kms) * Setup the LCDC/LVDS path: RGB2 -> DMA_P -> LCDC -> LVDS: */
- panel = detect_panel(dev, "qcom,lvds-panel"); + panel = detect_panel(dev); if (IS_ERR(panel)) { ret = PTR_ERR(panel); dev_err(dev->dev, "failed to detect LVDS panel: %d\n", ret); diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h index e7c5ea1..0cbeb1d 100644 --- a/drivers/gpu/drm/msm/msm_drv.h +++ b/drivers/gpu/drm/msm/msm_drv.h @@ -30,6 +30,7 @@ #include <linux/list.h> #include <linux/iommu.h> #include <linux/types.h> +#include <linux/of_graph.h> #include <asm/sizes.h>
#ifndef CONFIG_OF
drm/msm currently relies on phandles/child nodes to get data about connected panels to LVDS and DSI. This method has known limitations.
Use device graphs in DT to represent the connections between the encoder outputs and the panels. Use of_graph helpers in the driver to get the panel device node.
The usage of device graphs should also simplify management in dual dsi mode. I haven't tried this out yet, though.
changes in v3:
- Some changes suggested by Hai - error handling when using of_graph helpers
changes in v2:
- Fix usage of of_node_put()
Archit Taneja (3): drm/msm: dsi host: add missing of_node_put() drm/msm: dsi host: Use device graph parsing to parse connected panel drm/msm: mdp4 lvds: get panel node via of graph parsing
Documentation/devicetree/bindings/drm/msm/dsi.txt | 15 +++++ drivers/gpu/drm/msm/dsi/dsi_host.c | 68 ++++++++++++++++++----- drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c | 33 ++++++++--- drivers/gpu/drm/msm/msm_drv.h | 1 + 4 files changed, 93 insertions(+), 24 deletions(-)
Decrement device node refcount if of_get_child_by_name is successfully called.
Signed-off-by: Archit Taneja architt@codeaurora.org --- drivers/gpu/drm/msm/dsi/dsi_host.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index de04009..e2c9610 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -1582,8 +1582,12 @@ int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer) node = of_get_child_by_name(msm_host->pdev->dev.of_node, "panel"); if (node) { - if (!of_drm_find_panel(node)) + if (!of_drm_find_panel(node)) { + of_node_put(node); return -EPROBE_DEFER; + } + + of_node_put(node); } } }
The dsi host looks for the connected panel node by parsing for a child named 'panel'. This hierarchy isn't very flexible. The connected panel is forced to be a child to the dsi host, and hence, a mipi dsi device. This isn't suitable for dsi devices that don't use mipi dsi as their control bus.
Follow the of_graph approach of creating ports and endpoints to represent the connections between the dsi host and the panel connected to it. In our case, the dsi host will only have one output port, linked to the panel's input port.
Update DT binding documentation with device graph usage info.
v3: - Fix return value checks of of_graph_* calls. - Don't make port a mandatory DT property - Fix defer check when no panel node specified - Rename parse_dt func to align with other dsi_host funcs
Reviewed-by: Hai Li hali@codeaurora.org Signed-off-by: Archit Taneja architt@codeaurora.org --- Documentation/devicetree/bindings/drm/msm/dsi.txt | 15 +++++ drivers/gpu/drm/msm/dsi/dsi_host.c | 72 +++++++++++++++++------ 2 files changed, 68 insertions(+), 19 deletions(-)
diff --git a/Documentation/devicetree/bindings/drm/msm/dsi.txt b/Documentation/devicetree/bindings/drm/msm/dsi.txt index cd8fe6c..6cada5a 100644 --- a/Documentation/devicetree/bindings/drm/msm/dsi.txt +++ b/Documentation/devicetree/bindings/drm/msm/dsi.txt @@ -38,6 +38,9 @@ Optional properties: driving a 2-DSI panel whose 2 links need receive command simultaneously. - interrupt-parent: phandle to the MDP block if the interrupt signal is routed through MDP block +- port: DSI controller output port. This contains one endpoint subnode, with its + remote-endpoint set to the phandle of the connected panel's endpoint. + See Documentation/devicetree/bindings/graph.txt for device graph info.
DSI PHY: Required properties: @@ -101,6 +104,18 @@ Example:
power-supply = <...>; backlight = <...>; + + port { + panel_in: endpoint { + remote-endpoint = <&dsi0_out>; + }; + }; + }; + + port { + dsi0_out: endpoint { + remote-endpoint = <&panel_in>; + }; }; };
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index e2c9610..914559c 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -20,6 +20,7 @@ #include <linux/of_device.h> #include <linux/of_gpio.h> #include <linux/of_irq.h> +#include <linux/of_graph.h> #include <linux/regulator/consumer.h> #include <linux/spinlock.h> #include <video/mipi_display.h> @@ -1379,7 +1380,7 @@ static int dsi_host_attach(struct mipi_dsi_host *host, msm_host->format = dsi->format; msm_host->mode_flags = dsi->mode_flags;
- msm_host->panel_node = dsi->dev.of_node; + WARN_ON(dsi->dev.of_node != msm_host->panel_node);
/* Some gpios defined in panel DT need to be controlled by host */ ret = dsi_host_init_panel_gpios(msm_host, &dsi->dev); @@ -1429,6 +1430,48 @@ static struct mipi_dsi_host_ops dsi_host_ops = { .transfer = dsi_host_transfer, };
+static int dsi_host_parse_dt(struct msm_dsi_host *msm_host) +{ + struct device *dev = &msm_host->pdev->dev; + struct device_node *np = dev->of_node; + struct device_node *endpoint, *panel_node; + int ret; + + ret = of_property_read_u32(np, "qcom,dsi-host-index", &msm_host->id); + if (ret) { + dev_err(dev, "%s: host index not specified, ret=%d\n", + __func__, ret); + return ret; + } + + /* + * Get the first endpoint node. In our case, dsi has one output port + * to which the panel is connected. Don't return an error if a port + * isn't defined. It's possible that there is nothing connected to + * the dsi output. + */ + endpoint = of_graph_get_next_endpoint(np, NULL); + if (!endpoint) { + dev_dbg(dev, "%s: no endpoint\n", __func__); + return 0; + } + + /* Get panel node from the output port's endpoint data */ + panel_node = of_graph_get_remote_port_parent(endpoint); + if (!panel_node) { + dev_err(dev, "%s: no valid device\n", __func__); + of_node_put(endpoint); + return -ENODEV; + } + + of_node_put(endpoint); + of_node_put(panel_node); + + msm_host->panel_node = panel_node; + + return 0; +} + int msm_dsi_host_init(struct msm_dsi *msm_dsi) { struct msm_dsi_host *msm_host = NULL; @@ -1443,15 +1486,13 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi) goto fail; }
- ret = of_property_read_u32(pdev->dev.of_node, - "qcom,dsi-host-index", &msm_host->id); + msm_host->pdev = pdev; + + ret = dsi_host_parse_dt(msm_host); if (ret) { - dev_err(&pdev->dev, - "%s: host index not specified, ret=%d\n", - __func__, ret); + pr_err("%s: failed to parse dt\n", __func__); goto fail; } - msm_host->pdev = pdev;
ret = dsi_clk_init(msm_host); if (ret) { @@ -1559,7 +1600,6 @@ int msm_dsi_host_modeset_init(struct mipi_dsi_host *host, int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer) { struct msm_dsi_host *msm_host = to_msm_dsi_host(host); - struct device_node *node; int ret;
/* Register mipi dsi host */ @@ -1577,18 +1617,12 @@ int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer) * It makes sure panel is connected when fbcon detects * connector status and gets the proper display mode to * create framebuffer. + * Don't try to defer if there is nothing connected to the dsi + * output */ - if (check_defer) { - node = of_get_child_by_name(msm_host->pdev->dev.of_node, - "panel"); - if (node) { - if (!of_drm_find_panel(node)) { - of_node_put(node); - return -EPROBE_DEFER; - } - - of_node_put(node); - } + if (check_defer && msm_host->panel_node) { + if (!of_drm_find_panel(msm_host->panel_node)) + return -EPROBE_DEFER; } }
We currently get the output connected to LVDS by looking for a phandle called 'qcom,lvds-panel' under the mdp DT node.
Use the more standard of_graph approach to create an lvds output port, and retrieve the panel node from the port's endpoint data.
v3 - Fix return value checks of of_graph_* calls.
Tested-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org Signed-off-by: Archit Taneja architt@codeaurora.org --- drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c | 33 ++++++++++++++++++++++++--------- drivers/gpu/drm/msm/msm_drv.h | 1 + 2 files changed, 25 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c index 531e4ac..601dcc0 100644 --- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c +++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c @@ -241,22 +241,37 @@ int mdp4_enable(struct mdp4_kms *mdp4_kms) }
#ifdef CONFIG_OF -static struct drm_panel *detect_panel(struct drm_device *dev, const char *name) +static struct drm_panel *detect_panel(struct drm_device *dev) { - struct device_node *n; + struct device_node *endpoint, *panel_node; + struct device_node *np = dev->dev->of_node; struct drm_panel *panel = NULL;
- n = of_parse_phandle(dev->dev->of_node, name, 0); - if (n) { - panel = of_drm_find_panel(n); - if (!panel) - panel = ERR_PTR(-EPROBE_DEFER); + endpoint = of_graph_get_next_endpoint(np, NULL); + if (!endpoint) { + dev_err(dev->dev, "no valid endpoint\n"); + return ERR_PTR(-ENODEV); + } + + panel_node = of_graph_get_remote_port_parent(endpoint); + if (!panel_node) { + dev_err(dev->dev, "no valid panel node\n"); + of_node_put(endpoint); + return ERR_PTR(-ENODEV); + } + + of_node_put(endpoint); + + panel = of_drm_find_panel(panel_node); + if (!panel) { + of_node_put(panel_node); + return ERR_PTR(-EPROBE_DEFER); }
return panel; } #else -static struct drm_panel *detect_panel(struct drm_device *dev, const char *name) +static struct drm_panel *detect_panel(struct drm_device *dev) { // ??? maybe use a module param to specify which panel is attached? } @@ -294,7 +309,7 @@ static int modeset_init(struct mdp4_kms *mdp4_kms) * Setup the LCDC/LVDS path: RGB2 -> DMA_P -> LCDC -> LVDS: */
- panel = detect_panel(dev, "qcom,lvds-panel"); + panel = detect_panel(dev); if (IS_ERR(panel)) { ret = PTR_ERR(panel); dev_err(dev->dev, "failed to detect LVDS panel: %d\n", ret); diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h index e7c5ea1..0cbeb1d 100644 --- a/drivers/gpu/drm/msm/msm_drv.h +++ b/drivers/gpu/drm/msm/msm_drv.h @@ -30,6 +30,7 @@ #include <linux/list.h> #include <linux/iommu.h> #include <linux/types.h> +#include <linux/of_graph.h> #include <asm/sizes.h>
#ifndef CONFIG_OF
dri-devel@lists.freedesktop.org
-
Archit Taneja