Adds support for limitation of maximal pixel clock of HDMI
signal. This feature is needed on boards that contains
lines or bridges with frequency limitations.
Signed-off-by: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx>
---
.../devicetree/bindings/video/exynos_hdmi.txt | 4 ++++
drivers/gpu/drm/exynos/exynos_hdmi.c | 12 ++++++++++++
include/media/s5p_hdmi.h | 1 +
3 files changed, 17 insertions(+)
diff --git a/Documentation/devicetree/bindings/video/exynos_hdmi.txt b/Documentation/devicetree/bindings/video/exynos_hdmi.txt
index f9187a2..8718f8d 100644
--- a/Documentation/devicetree/bindings/video/exynos_hdmi.txt
+++ b/Documentation/devicetree/bindings/video/exynos_hdmi.txt
@@ -28,6 +28,10 @@ Required properties:
- ddc: phandle to the hdmi ddc node
- phy: phandle to the hdmi phy node
+Optional properties:
+- max-pixel-clock: used to limit the maximal pixel clock if a board has lines,
+ connectors or bridges not capable of carring higher frequencies
+
Example:
hdmi {
diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 2a18f4e..404f1b7 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -195,6 +195,7 @@ struct hdmi_context {
struct hdmi_resources res;
int hpd_gpio;
+ u32 max_pixel_clock;
enum hdmi_type type;
};
@@ -887,6 +888,9 @@ static int hdmi_mode_valid(struct drm_connector *connector,
if (ret)
return MODE_BAD;
+ if (mode->clock * 1000 > hdata->max_pixel_clock)
+ return MODE_BAD;
+
ret = hdmi_find_phy_conf(hdata, mode->clock * 1000);
if (ret < 0)
return MODE_BAD;
@@ -2031,6 +2035,8 @@ static struct s5p_hdmi_platform_data *drm_hdmi_dt_parse_pdata
return NULL;
}
+ of_property_read_u32(np, "max-pixel-clock", &pd->max_pixel_clock);
+
return pd;
}
@@ -2067,6 +2073,11 @@ static int hdmi_probe(struct platform_device *pdev)
if (!pdata)
return -EINVAL;
+ if (!pdata->max_pixel_clock) {
+ DRM_INFO("max-pixel-clock is zero, using INF\n");
+ pdata->max_pixel_clock = U32_MAX;
+ }
+
hdata = devm_kzalloc(dev, sizeof(struct hdmi_context), GFP_KERNEL);
if (!hdata)
return -ENOMEM;
@@ -2083,6 +2094,7 @@ static int hdmi_probe(struct platform_device *pdev)
hdata->type = drv_data->type;
hdata->hpd_gpio = pdata->hpd_gpio;
+ hdata->max_pixel_clock = pdata->max_pixel_clock;
hdata->dev = dev;
ret = hdmi_resources_init(hdata);
diff --git a/include/media/s5p_hdmi.h b/include/media/s5p_hdmi.h
index 181642b..7272d65 100644
--- a/include/media/s5p_hdmi.h
+++ b/include/media/s5p_hdmi.h
@@ -31,6 +31,7 @@ struct s5p_hdmi_platform_data {
int mhl_bus;
struct i2c_board_info *mhl_info;
int hpd_gpio;
+ u32 max_pixel_clock;
};
#endif /* S5P_HDMI_H */
--
1.7.9.5
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