[PATCH v2 01/12] drm: bridge/dw_hdmi: adjust n/cts setting order

[Yakir Yang]

For Designerware HDMI, the following write sequence is recommended:
1. aud_n3 (set bit ncts_atomic_write if desired)
2. aud_cts3 (set CTS_manual and CTS value if desired/enabled)
3. aud_cts2 (required in CTS_manual)
4. aud_cts1 (required in CTS_manual)
5. aud_n3 (bit ncts_atomic_write with same value as in step 1.)
6. aud_n2
7. aud_n1

Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
---
Changes in v2:
- adjust n/cts setting order

 drivers/gpu/drm/bridge/dw_hdmi.c | 37 +++++++++++++++++++++----------------
 drivers/gpu/drm/bridge/dw_hdmi.h |  6 ++++++
 2 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index cd6a706..423addc 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -177,26 +177,31 @@ static void hdmi_mask_writeb(struct dw_hdmi *hdmi, u8 data, unsigned int reg,
 	hdmi_modb(hdmi, data << shift, mask, reg);
 }
 
-static void hdmi_set_clock_regenerator_n(struct dw_hdmi *hdmi,
-					 unsigned int value)
+static void hdmi_regenerate_n_cts(struct dw_hdmi *hdmi, unsigned int n,
+				  unsigned int cts)
 {
-	hdmi_writeb(hdmi, value & 0xff, HDMI_AUD_N1);
-	hdmi_writeb(hdmi, (value >> 8) & 0xff, HDMI_AUD_N2);
-	hdmi_writeb(hdmi, (value >> 16) & 0x0f, HDMI_AUD_N3);
+	/* set ncts_atomic_write */
+	hdmi_modb(hdmi, HDMI_AUD_N3_NCTS_ATOMIC_WRITE_SET,
+		  HDMI_AUD_N3_NCTS_ATOMIC_WRITE_MASK, HDMI_AUD_N3);
+
+	/* set cts manual */
+	hdmi_modb(hdmi, HDMI_AUD_CTS3_CTS_MANUAL,
+		  HDMI_AUD_CTS3_CTS_MANUAL, HDMI_AUD_CTS3);
 
 	/* nshift factor = 0 */
 	hdmi_modb(hdmi, 0, HDMI_AUD_CTS3_N_SHIFT_MASK, HDMI_AUD_CTS3);
-}
-
-static void hdmi_regenerate_cts(struct dw_hdmi *hdmi, unsigned int cts)
-{
-	/* Must be set/cleared first */
-	hdmi_modb(hdmi, 0, HDMI_AUD_CTS3_CTS_MANUAL, HDMI_AUD_CTS3);
 
-	hdmi_writeb(hdmi, cts & 0xff, HDMI_AUD_CTS1);
+	/* set cts values */
+	hdmi_modb(hdmi, ((cts >> 16) & HDMI_AUD_CTS3_AUDCTS19_16_MASK),
+		  HDMI_AUD_CTS3_AUDCTS19_16_MASK, HDMI_AUD_CTS3);
 	hdmi_writeb(hdmi, (cts >> 8) & 0xff, HDMI_AUD_CTS2);
-	hdmi_writeb(hdmi, ((cts >> 16) & HDMI_AUD_CTS3_AUDCTS19_16_MASK) |
-		    HDMI_AUD_CTS3_CTS_MANUAL, HDMI_AUD_CTS3);
+	hdmi_writeb(hdmi, cts & 0xff, HDMI_AUD_CTS1);
+
+	/* set n values */
+	hdmi_modb(hdmi, (n >> 16) & HDMI_AUD_N3_AUDN19_16_MASK,
+		  HDMI_AUD_N3_AUDN19_16_MASK, HDMI_AUD_N3);
+	hdmi_writeb(hdmi, (n >> 8) & 0xff, HDMI_AUD_N2);
+	hdmi_writeb(hdmi, n & 0xff, HDMI_AUD_N1);
 }
 
 static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
@@ -355,8 +360,8 @@ static void hdmi_set_clk_regenerator(struct dw_hdmi *hdmi,
 		__func__, hdmi->sample_rate, hdmi->ratio,
 		pixel_clk, clk_n, clk_cts);
 
-	hdmi_set_clock_regenerator_n(hdmi, clk_n);
-	hdmi_regenerate_cts(hdmi, clk_cts);
+	hdmi_regenerate_n_cts(hdmi, clk_n, clk_cts);
+	hdmi_set_schnl(hdmi);
 }
 
 static void hdmi_init_clk_regenerator(struct dw_hdmi *hdmi)
diff --git a/drivers/gpu/drm/bridge/dw_hdmi.h b/drivers/gpu/drm/bridge/dw_hdmi.h
index 175dbc8..bc53452 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.h
+++ b/drivers/gpu/drm/bridge/dw_hdmi.h
@@ -884,6 +884,12 @@ enum {
 	HDMI_PHY_I2CM_CTLINT_ADDR_ARBITRATION_POL = 0x08,
 	HDMI_PHY_I2CM_CTLINT_ADDR_ARBITRATION_MASK = 0x04,
 
+/* AUD_N3 field values */
+	HDMI_AUD_N3_NCTS_ATOMIC_WRITE_MASK = 0x80,
+	HDMI_AUD_N3_NCTS_ATOMIC_WRITE_SET = 0x80,
+	HDMI_AUD_N3_NCTS_ATOMIC_WRITE_CLEAR = 0x00,
+	HDMI_AUD_N3_AUDN19_16_MASK = 0x0f,
+
 /* AUD_CTS3 field values */
 	HDMI_AUD_CTS3_N_SHIFT_OFFSET = 5,
 	HDMI_AUD_CTS3_N_SHIFT_MASK = 0xe0,
-- 
2.1.2


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