[PATCH 4/4] drm/i2c: tda998x: add support for pixel repeated modes
From: linux@armlinux.org.uk (Russell King - ARM Linux)
Date: 2018-07-31 09:42:47
Also in:
dri-devel
On Tue, Jul 31, 2018 at 10:26:55AM +0100, Russell King wrote:
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.
Note that this is an experimental patch - I haven't yet been able to test it beyond "does it still work with non-doubled modes". They tend to be low resolution modes, because the doubling is needed to maintain a minimum clock rate over HDMI. The doubled modes are (eg): VIC Name 6 720(1440)x480i at 60Hz 7 720(1440)x480i at 60Hz 8 720(1440)x240 at 60Hz 21 720(1440)x576i at 50Hz 22 720(1440)x576i at 50Hz 23 720(1440)x288 at 50Hz 24 720(1440)x288 at 50Hz They are probably only found with TVs rather than monitors.
quoted hunk ↗ jump to hunk
Signed-off-by: Russell King <redacted> --- 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
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