Hello,
The following patches:
- Add support for configuring the width-mm and height-mm DRM mode
properties in the SimpleDRM driver via Device Tree
- Document these two new Device Tree properties
This is useful for allowing interfaces such as Phosh to calculate
proper scaling values and for early boot code knowing if hi-dpi
rendering is necessary.
Changes since v2:
- Remove $ref property (because it is an SI unit)
- Extend commit messages
Rayyan Ansari (2):
drm/simpledrm: Allow physical width and height configuration via DT
dt-bindings: display: simple-framebuffer: Document physical width and
height properties
.../bindings/display/simple-framebuffer.yaml | 6 ++
drivers/gpu/drm/tiny/simpledrm.c | 60 ++++++++++++++++---
2 files changed, 57 insertions(+), 9 deletions(-)
--
2.39.1
Add optional width-mm and height-mm devicetree properties and use this
to set the DRM Display Mode instead of calculating it based on an
average DPI.
Signed-off-by: Rayyan Ansari <[email protected]>
---
drivers/gpu/drm/tiny/simpledrm.c | 60 +++++++++++++++++++++++++++-----
1 file changed, 51 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 162eb44dcba8..7aab7fa572f0 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -128,6 +128,23 @@ simplefb_read_u32_of(struct drm_device *dev, struct device_node *of_node,
return ret;
}
+static int
+simplefb_read_u32_of_opt(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 == -EINVAL) {
+ *value = 0;
+ ret = 0;
+ } else if (ret) {
+ drm_err(dev, "simplefb: cannot 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)
@@ -184,6 +201,19 @@ simplefb_get_format_of(struct drm_device *dev, struct device_node *of_node)
return simplefb_get_validated_format(dev, format);
}
+static int
+simplefb_get_mm_of(struct drm_device *dev, struct device_node *of_node,
+ const char *name)
+{
+ int mm;
+ int ret = simplefb_read_u32_of_opt(dev, of_node, name, &mm);
+
+ if (ret)
+ return ret;
+ return simplefb_get_validated_int(dev, name, mm);
+}
+
+
/*
* Simple Framebuffer device
*/
@@ -599,16 +629,12 @@ static const struct drm_mode_config_funcs simpledrm_mode_config_funcs = {
*/
static struct drm_display_mode simpledrm_mode(unsigned int width,
- unsigned int height)
+ unsigned int height,
+ unsigned int width_mm,
+ unsigned int height_mm)
{
- /*
- * Assume a monitor resolution of 96 dpi to
- * get a somewhat reasonable screen size.
- */
const struct drm_display_mode mode = {
- DRM_MODE_INIT(60, width, height,
- DRM_MODE_RES_MM(width, 96ul),
- DRM_MODE_RES_MM(height, 96ul))
+ DRM_MODE_INIT(60, width, height, width_mm, height_mm)
};
return mode;
@@ -622,6 +648,7 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
struct simpledrm_device *sdev;
struct drm_device *dev;
int width, height, stride;
+ int width_mm = 0, height_mm = 0;
const struct drm_format_info *format;
struct resource *res, *mem;
void __iomem *screen_base;
@@ -676,6 +703,12 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
format = simplefb_get_format_of(dev, of_node);
if (IS_ERR(format))
return ERR_CAST(format);
+ width_mm = simplefb_get_mm_of(dev, of_node, "width-mm");
+ if (width_mm < 0)
+ return ERR_PTR(width_mm);
+ height_mm = simplefb_get_mm_of(dev, of_node, "height-mm");
+ if (height_mm < 0)
+ return ERR_PTR(height_mm);
} else {
drm_err(dev, "no simplefb configuration found\n");
return ERR_PTR(-ENODEV);
@@ -686,7 +719,16 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
return ERR_PTR(-EINVAL);
}
- sdev->mode = simpledrm_mode(width, height);
+ /*
+ * Assume a monitor resolution of 96 dpi if physical dimensions
+ * are not specified to get a somewhat reasonable screen size.
+ */
+ if (!width_mm)
+ width_mm = DRM_MODE_RES_MM(width, 96ul);
+ if (!height_mm)
+ height_mm = DRM_MODE_RES_MM(height, 96ul);
+
+ sdev->mode = simpledrm_mode(width, height, width_mm, height_mm);
sdev->format = format;
sdev->pitch = stride;
--
2.39.1
Document the optional width-mm and height-mm simple-framebuffer
properties.
Signed-off-by: Rayyan Ansari <[email protected]>
---
.../devicetree/bindings/display/simple-framebuffer.yaml | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/Documentation/devicetree/bindings/display/simple-framebuffer.yaml b/Documentation/devicetree/bindings/display/simple-framebuffer.yaml
index dd64f70b5014..4ae33a4d2da9 100644
--- a/Documentation/devicetree/bindings/display/simple-framebuffer.yaml
+++ b/Documentation/devicetree/bindings/display/simple-framebuffer.yaml
@@ -106,6 +106,12 @@ properties:
- x2r10g10b10
- x8r8g8b8
+ width-mm:
+ description: Physical width of the display in millimetres
+
+ height-mm:
+ description: Physical height of the display in millimetres
+
display:
$ref: /schemas/types.yaml#/definitions/phandle
description: Primary display hardware node
--
2.39.1
On 24/01/2023 23:41, Rayyan Ansari wrote:
> Document the optional width-mm and height-mm simple-framebuffer
> properties.
As pointed in previous discussion - you should have panel node and take
the properties from it. The physical dimensions are not properties of
framebuffer device. These are properties of panel.
Best regards,
Krzysztof