drm: exynos: hdmi: add support for pixel clock limitation

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@samsung.com>
Change-Id: I4cc38e995feeaca77b73e9ea0197d67f99d57715

diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 87c3f42..a48cf75 100644 (file)
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -201,6 +201,7 @@ struct hdmi_context {
        struct hdmi_resources           res;
 
        int                             hpd_gpio;
+       u32                             max_pixel_clock;
 
        enum hdmi_type                  type;
 };
@@ -801,6 +802,8 @@ static int hdmi_check_mode(void *ctx, struct drm_display_mode *mode)
                (mode->flags & DRM_MODE_FLAG_INTERLACE) ? true :
                false, mode->clock * 1000);
 
+       if (mode->clock * 1000 > hdata->max_pixel_clock)
+               return -E2BIG;
        ret = hdmi_find_phy_conf(hdata, mode->clock * 1000);
        if (ret < 0)
                return ret;
@@ -1868,6 +1871,8 @@ 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;
 }
 #else
@@ -1934,6 +1939,11 @@ static int hdmi_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
+       if (!pdata->max_pixel_clock) {
+               DRM_LOG("max-pixel-clock is zero, using INF\n");
+               pdata->max_pixel_clock = ULONG_MAX;
+       }
+
        drm_hdmi_ctx = devm_kzalloc(dev, sizeof(*drm_hdmi_ctx),
                                                                GFP_KERNEL);
        if (!drm_hdmi_ctx)
@@ -1964,6 +1974,7 @@ static int hdmi_probe(struct platform_device *pdev)
        }
 
        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 (file)
--- 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 */