drm/vc4: hdmi: Add PHY RNG enable / disable function

Let's continue the implementation of hooks for the parts that change in the
BCM2711 SoC with the PHY RNG setup.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/216155f1c0b83e622ac60a2f7d00eb707de3acba.1599120059.git-series.maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -762,9 +762,9 @@ static int vc4_hdmi_audio_trigger(struct snd_pcm_substream *substream, int cmd,
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		vc4_hdmi_set_audio_infoframe(encoder);
-		HDMI_WRITE(HDMI_TX_PHY_CTL_0,
-			   HDMI_READ(HDMI_TX_PHY_CTL_0) &
-			   ~VC4_HDMI_TX_PHY_RNG_PWRDN);
+
+		if (vc4_hdmi->variant->phy_rng_enable)
+			vc4_hdmi->variant->phy_rng_enable(vc4_hdmi);
 
 		HDMI_WRITE(HDMI_MAI_CTL,
 			   VC4_SET_FIELD(vc4_hdmi->audio.channels,
@@ -776,9 +776,10 @@ static int vc4_hdmi_audio_trigger(struct snd_pcm_substream *substream, int cmd,
 			   VC4_HD_MAI_CTL_DLATE |
 			   VC4_HD_MAI_CTL_ERRORE |
 			   VC4_HD_MAI_CTL_ERRORF);
-		HDMI_WRITE(HDMI_TX_PHY_CTL_0,
-			   HDMI_READ(HDMI_TX_PHY_CTL_0) |
-			   VC4_HDMI_TX_PHY_RNG_PWRDN);
+
+		if (vc4_hdmi->variant->phy_rng_disable)
+			vc4_hdmi->variant->phy_rng_disable(vc4_hdmi);
+
 		break;
 	default:
 		break;
@@ -1432,6 +1433,8 @@ static const struct vc4_hdmi_variant bcm2835_variant = {
 	.reset			= vc4_hdmi_reset,
 	.phy_init		= vc4_hdmi_phy_init,
 	.phy_disable		= vc4_hdmi_phy_disable,
+	.phy_rng_enable		= vc4_hdmi_phy_rng_enable,
+	.phy_rng_disable	= vc4_hdmi_phy_rng_disable,
 };
 
 static const struct of_device_id vc4_hdmi_dt_match[] = {

drivers/gpu/drm/vc4/vc4_hdmi.h

@@ -47,6 +47,12 @@ struct vc4_hdmi_variant {
 
 	/* Callback to disable the PHY */
 	void (*phy_disable)(struct vc4_hdmi *vc4_hdmi);
+
+	/* Callback to enable the RNG in the PHY */
+	void (*phy_rng_enable)(struct vc4_hdmi *vc4_hdmi);
+
+	/* Callback to disable the RNG in the PHY */
+	void (*phy_rng_disable)(struct vc4_hdmi *vc4_hdmi);
 };
 
 /* HDMI audio information */
@@ -107,5 +113,7 @@ encoder_to_vc4_hdmi(struct drm_encoder *encoder)
 void vc4_hdmi_phy_init(struct vc4_hdmi *vc4_hdmi,
 		       struct drm_display_mode *mode);
 void vc4_hdmi_phy_disable(struct vc4_hdmi *vc4_hdmi);
+void vc4_hdmi_phy_rng_enable(struct vc4_hdmi *vc4_hdmi);
+void vc4_hdmi_phy_rng_disable(struct vc4_hdmi *vc4_hdmi);
 
 #endif /* _VC4_HDMI_H_ */

drivers/gpu/drm/vc4/vc4_hdmi_phy.c

@@ -7,6 +7,7 @@
  */
 
 #include "vc4_hdmi.h"
+#include "vc4_regs.h"
 #include "vc4_hdmi_regs.h"
 
 void vc4_hdmi_phy_init(struct vc4_hdmi *vc4_hdmi, struct drm_display_mode *mode)
@@ -23,3 +24,17 @@ void vc4_hdmi_phy_disable(struct vc4_hdmi *vc4_hdmi)
 {
 	HDMI_WRITE(HDMI_TX_PHY_RESET_CTL, 0xf << 16);
 }
+
+void vc4_hdmi_phy_rng_enable(struct vc4_hdmi *vc4_hdmi)
+{
+	HDMI_WRITE(HDMI_TX_PHY_CTL_0,
+		   HDMI_READ(HDMI_TX_PHY_CTL_0) &
+		   ~VC4_HDMI_TX_PHY_RNG_PWRDN);
+}
+
+void vc4_hdmi_phy_rng_disable(struct vc4_hdmi *vc4_hdmi)
+{
+	HDMI_WRITE(HDMI_TX_PHY_CTL_0,
+		   HDMI_READ(HDMI_TX_PHY_CTL_0) |
+		   VC4_HDMI_TX_PHY_RNG_PWRDN);
+}