[PATCH 4/4] drm/i2c: tda998x: add support for pixel repeated modes

[Russell King]

TDA998x has no support for pixel repeated modes, and the code notes this
as a "TODO" item.  The implementation appears to be relatively simple,
so lets add it.

We need to calculate the serializer clock divisor based on the TMDS
clock rate, set the repeat control, and set the serializer pixel
repeat count.  Since the audio code needs the actual TMDS clock,
record that.

Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>
---
 drivers/gpu/drm/i2c/tda998x_drv.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index a31809ce30e2..08ce28cbdec4 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -241,6 +241,7 @@ struct tda998x_priv {
 # define HVF_CNTRL_1_PAD(x)       (((x) & 3) << 4)
 # define HVF_CNTRL_1_SEMI_PLANAR  (1 << 6)
 #define REG_RPT_CNTRL             REG(0x00, 0xf0)     /* write */
+# define RPT_CNTRL_REPEAT(x)      ((x) & 15)
 #define REG_I2S_FORMAT            REG(0x00, 0xfc)     /* read/write */
 # define I2S_FORMAT(x)            (((x) & 3) << 0)
 #define REG_AIP_CLKSEL            REG(0x00, 0xfd)     /* write */
@@ -1342,7 +1343,7 @@ static void tda998x_bridge_mode_set(struct drm_bridge *bridge,
 	u16 vwin1_line_s, vwin1_line_e;
 	u16 vwin2_line_s, vwin2_line_e;
 	u16 de_pix_s, de_pix_e;
-	u8 reg, div, rep;
+	u8 reg, div, rep, sel_clk;
 
 	/*
 	 * Internally TDA998x is using ITU-R BT.656 style sync but
@@ -1405,7 +1406,16 @@ static void tda998x_bridge_mode_set(struct drm_bridge *bridge,
 			       (mode->vsync_end - mode->vsync_start)/2;
 	}
 
-	tmds_clock = mode->clock;
+	/*
+	 * Select pixel repeat depending on the double-clock flag
+	 * (which means we have to repeat each pixel once.)
+	 */
+	rep = mode->flags & DRM_MODE_FLAG_DBLCLK ? 1 : 0;
+	sel_clk = SEL_CLK_ENA_SC_CLK | SEL_CLK_SEL_CLK1 |
+		  SEL_CLK_SEL_VRF_CLK(rep ? 2 : 0);
+
+	/* the TMDS clock is scaled up by the pixel repeat */
+	tmds_clock = mode->clock * (1 + rep);
 
 	/*
 	 * The divisor is power-of-2. The TDA9983B datasheet gives
@@ -1421,6 +1431,8 @@ static void tda998x_bridge_mode_set(struct drm_bridge *bridge,
 
 	mutex_lock(&priv->audio_mutex);
 
+	priv->tmds_clock = tmds_clock;
+
 	/* mute the audio FIFO: */
 	reg_set(priv, REG_AIP_CNTRL_0, AIP_CNTRL_0_RST_FIFO);
 
@@ -1443,12 +1455,8 @@ static void tda998x_bridge_mode_set(struct drm_bridge *bridge,
 	reg_write(priv, REG_SERIALIZER, 0);
 	reg_write(priv, REG_HVF_CNTRL_1, HVF_CNTRL_1_VQR(0));
 
-	/* TODO enable pixel repeat for pixel rates less than 25Msamp/s */
-	rep = 0;
-	reg_write(priv, REG_RPT_CNTRL, 0);
-	reg_write(priv, REG_SEL_CLK, SEL_CLK_SEL_VRF_CLK(0) |
-			SEL_CLK_SEL_CLK1 | SEL_CLK_ENA_SC_CLK);
-
+	reg_write(priv, REG_RPT_CNTRL, RPT_CNTRL_REPEAT(rep));
+	reg_write(priv, REG_SEL_CLK, sel_clk);
 	reg_write(priv, REG_PLL_SERIAL_2, PLL_SERIAL_2_SRL_NOSC(div) |
 			PLL_SERIAL_2_SRL_PR(rep));
 
@@ -1516,8 +1524,6 @@ static void tda998x_bridge_mode_set(struct drm_bridge *bridge,
 	/* must be last register set: */
 	reg_write(priv, REG_TBG_CNTRL_0, 0);
 
-	priv->tmds_clock = adjusted_mode->clock;
-
 	/* CEA-861B section 6 says that:
 	 * CEA version 1 (CEA-861) has no support for infoframes.
 	 * CEA version 2 (CEA-861A) supports version 1 AVI infoframes,
-- 
2.7.4