drm/tegra: rgb: Demidlayer

Implement encoder and connector within the RGB driver itself using the
Tegra output helpers rather than using the Tegra output as midlayer. By
doing so one level of indirection is removed and output drivers become
more flexible while keeping the majority of the advantages provided by
the common output helpers.

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

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 90909883e739..286cc8ce0c66 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -994,6 +994,7 @@ static int tegra_dc_wait_idle(struct tegra_dc *dc, unsigned long timeout)
 static void tegra_crtc_disable(struct drm_crtc *crtc)
 {
 	struct tegra_dc *dc = to_tegra_dc(crtc);
+	u32 value;
 
 	if (!tegra_dc_idle(dc)) {
 		tegra_dc_stop(dc);
@@ -1005,6 +1006,29 @@ static void tegra_crtc_disable(struct drm_crtc *crtc)
 		tegra_dc_wait_idle(dc, 100);
 	}
 
+	/*
+	 * This should really be part of the RGB encoder driver, but clearing
+	 * these bits has the side-effect of stopping the display controller.
+	 * When that happens no VBLANK interrupts will be raised. At the same
+	 * time the encoder is disabled before the display controller, so the
+	 * above code is always going to timeout waiting for the controller
+	 * to go idle.
+	 *
+	 * Given the close coupling between the RGB encoder and the display
+	 * controller doing it here is still kind of okay. None of the other
+	 * encoder drivers require these bits to be cleared.
+	 *
+	 * XXX: Perhaps given that the display controller is switched off at
+	 * this point anyway maybe clearing these bits isn't even useful for
+	 * the RGB encoder?
+	 */
+	if (dc->rgb) {
+		value = tegra_dc_readl(dc, DC_CMD_DISPLAY_POWER_CONTROL);
+		value &= ~(PW0_ENABLE | PW1_ENABLE | PW2_ENABLE | PW3_ENABLE |
+			   PW4_ENABLE | PM0_ENABLE | PM1_ENABLE);
+		tegra_dc_writel(dc, value, DC_CMD_DISPLAY_POWER_CONTROL);
+	}
+
 	drm_crtc_vblank_off(crtc);
 	tegra_dc_commit(dc);
 }