[PATCH 5/9] drm/simplekms: Initialize framebuffer data from device-tree node

[Thomas Zimmermann]

A firmware framebuffer might also be specified via device-tree files. If
no device platform data is given, try the DT device node.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 drivers/gpu/drm/tiny/simplekms.c | 84 ++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/drivers/gpu/drm/tiny/simplekms.c b/drivers/gpu/drm/tiny/simplekms.c
index ac2ebfcedd22..87636307aa4f 100644
--- a/drivers/gpu/drm/tiny/simplekms.c
+++ b/drivers/gpu/drm/tiny/simplekms.c
@@ -113,6 +113,76 @@ simplefb_get_format_pd(struct drm_device *dev,
 	return simplefb_get_validated_format(dev, pd->format);
 }
 
+static int
+simplefb_read_u32_of(struct drm_device *dev, struct device_node *of_node,
+		     const char* name, u32 *value)
+{
+	int ret = of_property_read_u32(of_node, name, value);
+	if (ret)
+		drm_err(dev, "simplefb: can't parse framebuffer %s: error %d\n",
+			name, ret);
+	return ret;
+}
+
+static int
+simplefb_read_string_of(struct drm_device *dev, struct device_node *of_node,
+			const char* name, const char **value)
+{
+	int ret = of_property_read_string(of_node, name, value);
+	if (ret)
+		drm_err(dev, "simplefb: can't parse framebuffer %s: error %d\n",
+			name, ret);
+	return ret;
+}
+
+static int
+simplefb_get_width_of(struct drm_device *dev, struct device_node *of_node)
+{
+	int ret;
+	u32 width;
+
+	ret = simplefb_read_u32_of(dev, of_node, "width", &width);
+	if (ret)
+		return ret;
+	return simplefb_get_validated_int0(dev, "width", width);
+}
+
+static int
+simplefb_get_height_of(struct drm_device *dev, struct device_node *of_node)
+{
+	int ret;
+	u32 height;
+
+	ret = simplefb_read_u32_of(dev, of_node, "height", &height);
+	if (ret)
+		return ret;
+	return simplefb_get_validated_int0(dev, "height", height);
+}
+
+static int
+simplefb_get_stride_of(struct drm_device *dev, struct device_node *of_node)
+{
+	int ret;
+	u32 stride;
+
+	ret = simplefb_read_u32_of(dev, of_node, "stride", &stride);
+	if (ret)
+		return ret;
+	return simplefb_get_validated_int(dev, "stride", stride);
+}
+
+static const struct drm_format_info *
+simplefb_get_format_of(struct drm_device *dev, struct device_node *of_node)
+{
+	int ret;
+	const char *format;
+
+	ret = simplefb_read_string_of(dev, of_node, "format", &format);
+	if (ret)
+		return ERR_PTR(ret);
+	return simplefb_get_validated_format(dev, format);
+}
+
 /*
  * Simple Framebuffer device
  */
@@ -163,6 +233,7 @@ static int simplekms_device_init_fb(struct simplekms_device *sdev)
 	struct drm_device *dev = &sdev->dev;
 	struct platform_device *pdev = sdev->pdev;
 	const struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
+	struct device_node *of_node = pdev->dev.of_node;
 
 	if (pd) {
 		width = simplefb_get_width_pd(dev, pd);
@@ -177,6 +248,19 @@ static int simplekms_device_init_fb(struct simplekms_device *sdev)
 		format = simplefb_get_format_pd(dev, pd);
 		if (IS_ERR(format))
 			return PTR_ERR(format);
+	} else if (of_node) {
+		width = simplefb_get_width_of(dev, of_node);
+		if (width < 0)
+			return width;
+		height = simplefb_get_height_of(dev, of_node);
+		if (height < 0)
+			return height;
+		stride = simplefb_get_stride_of(dev, of_node);
+		if (stride < 0)
+			return stride;
+		format = simplefb_get_format_of(dev, of_node);
+		if (IS_ERR(format))
+			return PTR_ERR(format);
 	} else {
 		drm_err(dev, "no simplefb configuration found\n");
 		return -ENODEV;
-- 
2.27.0