[PATCH 1/3] drm/omap: Populate DSS children in omapdss driver

[Laurent Pinchart]

The DSS DT node contains children that describe the DSS components
(DISPC and internal encoders). Each of those components is handled by a
platform driver, and thus needs to be backed by a platform device.

The corresponding platform devices are created in arch code by a call to
of_platform_populate(). While this approach can be considered as
correct, it performs a task in arch code that can be equally well
performed in driver code. To simplify arch code, move the
of_platform_populate() call to the omapdss driver, and cleanup at remove
time by calling of_platform_depopulate().

This has the added benefit of not allowing DSS components to probe
before the DSS itself, which led to runtime PM issues when the DSS probe
is deferred.

Fixes: 27d624527d99 ("drm/omap: dss: Acquire next dssdev at probe time")
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 arch/arm/mach-omap2/display.c     | 111 ++++++++++++++----------------
 drivers/gpu/drm/omapdrm/dss/dss.c |  11 ++-
 2 files changed, 63 insertions(+), 59 deletions(-)

diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
index 9500b6e27380..f86b72d1d59e 100644
--- a/arch/arm/mach-omap2/display.c
+++ b/arch/arm/mach-omap2/display.c
@@ -209,11 +209,61 @@ static int __init omapdss_init_fbdev(void)
 
 	return 0;
 }
-#else
-static inline int omapdss_init_fbdev(void)
+
+static const char * const omapdss_compat_names[] __initconst = {
+	"ti,omap2-dss",
+	"ti,omap3-dss",
+	"ti,omap4-dss",
+	"ti,omap5-dss",
+	"ti,dra7-dss",
+};
+
+static struct device_node * __init omapdss_find_dss_of_node(void)
 {
-	return 0;
+	struct device_node *node;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(omapdss_compat_names); ++i) {
+		node = of_find_compatible_node(NULL, NULL,
+			omapdss_compat_names[i]);
+		if (node)
+			return node;
+	}
+
+	return NULL;
 }
+
+static int __init omapdss_init_of(void)
+{
+	int r;
+	struct device_node *node;
+	struct platform_device *pdev;
+
+	/* only create dss helper devices if dss is enabled in the .dts */
+
+	node = omapdss_find_dss_of_node();
+	if (!node)
+		return 0;
+
+	if (!of_device_is_available(node))
+		return 0;
+
+	pdev = of_find_device_by_node(node);
+
+	if (!pdev) {
+		pr_err("Unable to find DSS platform device\n");
+		return -ENODEV;
+	}
+
+	r = of_platform_populate(node, NULL, NULL, &pdev->dev);
+	if (r) {
+		pr_err("Unable to populate DSS submodule devices\n");
+		return r;
+	}
+
+	return omapdss_init_fbdev();
+}
+omap_device_initcall(omapdss_init_of);
 #endif /* CONFIG_FB_OMAP2 */
 
 static void dispc_disable_outputs(void)
@@ -361,58 +411,3 @@ int omap_dss_reset(struct omap_hwmod *oh)
 
 	return r;
 }
-
-static const char * const omapdss_compat_names[] __initconst = {
-	"ti,omap2-dss",
-	"ti,omap3-dss",
-	"ti,omap4-dss",
-	"ti,omap5-dss",
-	"ti,dra7-dss",
-};
-
-static struct device_node * __init omapdss_find_dss_of_node(void)
-{
-	struct device_node *node;
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(omapdss_compat_names); ++i) {
-		node = of_find_compatible_node(NULL, NULL,
-			omapdss_compat_names[i]);
-		if (node)
-			return node;
-	}
-
-	return NULL;
-}
-
-static int __init omapdss_init_of(void)
-{
-	int r;
-	struct device_node *node;
-	struct platform_device *pdev;
-
-	/* only create dss helper devices if dss is enabled in the .dts */
-
-	node = omapdss_find_dss_of_node();
-	if (!node)
-		return 0;
-
-	if (!of_device_is_available(node))
-		return 0;
-
-	pdev = of_find_device_by_node(node);
-
-	if (!pdev) {
-		pr_err("Unable to find DSS platform device\n");
-		return -ENODEV;
-	}
-
-	r = of_platform_populate(node, NULL, NULL, &pdev->dev);
-	if (r) {
-		pr_err("Unable to populate DSS submodule devices\n");
-		return r;
-	}
-
-	return omapdss_init_fbdev();
-}
-omap_device_initcall(omapdss_init_of);
diff --git a/drivers/gpu/drm/omapdrm/dss/dss.c b/drivers/gpu/drm/omapdrm/dss/dss.c
index 1aaf260aa9b8..7553c7fc1c45 100644
--- a/drivers/gpu/drm/omapdrm/dss/dss.c
+++ b/drivers/gpu/drm/omapdrm/dss/dss.c
@@ -1484,16 +1484,23 @@ static int dss_probe(struct platform_device *pdev)
 						   dss);
 
 	/* Add all the child devices as components. */
+	r = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
+	if (r)
+		goto err_uninit_debugfs;
+
 	omapdss_gather_components(&pdev->dev);
 
 	device_for_each_child(&pdev->dev, &match, dss_add_child_component);
 
 	r = component_master_add_with_match(&pdev->dev, &dss_component_ops, match);
 	if (r)
-		goto err_uninit_debugfs;
+		goto err_of_depopulate;
 
 	return 0;
 
+err_of_depopulate:
+	of_platform_depopulate(&pdev->dev);
+
 err_uninit_debugfs:
 	dss_debugfs_remove_file(dss->debugfs.clk);
 	dss_debugfs_remove_file(dss->debugfs.dss);
@@ -1522,6 +1529,8 @@ static int dss_remove(struct platform_device *pdev)
 {
 	struct dss_device *dss = platform_get_drvdata(pdev);
 
+	of_platform_depopulate(&pdev->dev);
+
 	component_master_del(&pdev->dev, &dss_component_ops);
 
 	dss_debugfs_remove_file(dss->debugfs.clk);
-- 
Regards,

Laurent Pinchart