drm/vc4: Bring HDMI up from power off if necessary.

If the firmware hadn't brought up HDMI for us, we need to do its
power-on reset sequence (reset HD and and clear its STANDBY bits,
reset HDMI, and leave the PHY disabled).

Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 28 insertions, 1 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index c69c046..6e55760 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -495,6 +495,16 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 		goto err_put_i2c;
 	}
 
+	/* This is the rate that is set by the firmware.  The number
+	 * needs to be a bit higher than the pixel clock rate
+	 * (generally 148.5Mhz).
+	 */
+	ret = clk_set_rate(hdmi->hsm_clock, 163682864);
+	if (ret) {
+		DRM_ERROR("Failed to set HSM clock rate: %d\n", ret);
+		goto err_unprepare_pix;
+	}
+
 	ret = clk_prepare_enable(hdmi->hsm_clock);
 	if (ret) {
 		DRM_ERROR("Failed to turn on HDMI state machine clock: %d\n",
@@ -516,7 +526,24 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 	vc4->hdmi = hdmi;
 
 	/* HDMI core must be enabled. */
-	WARN_ON_ONCE((HD_READ(VC4_HD_M_CTL) & VC4_HD_M_ENABLE) == 0);
+	if (!(HD_READ(VC4_HD_M_CTL) & VC4_HD_M_ENABLE)) {
+		HD_WRITE(VC4_HD_M_CTL, VC4_HD_M_SW_RST);
+		udelay(1);
+		HD_WRITE(VC4_HD_M_CTL, 0);
+
+		HD_WRITE(VC4_HD_M_CTL, VC4_HD_M_ENABLE);
+
+		HDMI_WRITE(VC4_HDMI_SW_RESET_CONTROL,
+			   VC4_HDMI_SW_RESET_HDMI |
+			   VC4_HDMI_SW_RESET_FORMAT_DETECT);
+
+		HDMI_WRITE(VC4_HDMI_SW_RESET_CONTROL, 0);
+
+		/* PHY should be in reset, like
+		 * vc4_hdmi_encoder_disable() does.
+		 */
+		HDMI_WRITE(VC4_HDMI_TX_PHY_RESET_CTL, 0xf << 16);
+	}
 
 	drm_encoder_init(drm, hdmi->encoder, &vc4_hdmi_encoder_funcs,
 			 DRM_MODE_ENCODER_TMDS, NULL);