drm/tegra: Add tegra_dc_setup_clock() helper

This is a small helper that performs the basic steps required by all
output drivers to prepare the display controller for use with a given
encoder.

Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index e35e107..9090988 100644 (file)
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -1092,6 +1092,26 @@ static int tegra_crtc_setup_clk(struct drm_crtc *crtc,
        return 0;
 }
 
+int tegra_dc_setup_clock(struct tegra_dc *dc, struct clk *parent,
+                        unsigned long pclk, unsigned int div)
+{
+       u32 value;
+       int err;
+
+       err = clk_set_parent(dc->clk, parent);
+       if (err < 0) {
+               dev_err(dc->dev, "failed to set parent clock: %d\n", err);
+               return err;
+       }
+
+       DRM_DEBUG_KMS("rate: %lu, div: %u\n", clk_get_rate(dc->clk), div);
+
+       value = SHIFT_CLK_DIVIDER(div) | PIXEL_CLK_DIVIDER_PCD1;
+       tegra_dc_writel(dc, value, DC_DISP_DISP_CLOCK_CONTROL);
+
+       return 0;
+}
+
 static int tegra_crtc_mode_set(struct drm_crtc *crtc,
                               struct drm_display_mode *mode,
                               struct drm_display_mode *adjusted,

diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index d743397..e1374ec 100644 (file)
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -178,6 +178,8 @@ void tegra_dc_enable_vblank(struct tegra_dc *dc);
 void tegra_dc_disable_vblank(struct tegra_dc *dc);
 void tegra_dc_cancel_page_flip(struct drm_crtc *crtc, struct drm_file *file);
 void tegra_dc_commit(struct tegra_dc *dc);
+int tegra_dc_setup_clock(struct tegra_dc *dc, struct clk *parent,
+                        unsigned long pclk, unsigned int div);
 
 struct tegra_output_ops {
        int (*enable)(struct tegra_output *output);