diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-08-02 10:27:15 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-08-07 10:32:03 +0100 |
| commit | 926a299c42e38bbe8bb909eae0146e676b66afe4 (patch) | |
| tree | 76a65a5577508571a4789aa92bf28b3ecb02d5b2 /drivers/gpu/drm | |
| parent | a3d335f5de7cdd714737a9f8bdcc7b205b0f8d5e (diff) | |
drm/i2c: tda998x: correct PLL divider calculation
The serializer PLL divider is a power-of-two divider, so our calculation
which assumes that it's a numerical divider is incorrect. Replace it
with one that results in a power-of-two divider value instead.
Tested with all supported modes with a Samsung S24C750.
Tested-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/i2c/tda998x_drv.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c index 7313ff835f35..0df86e928191 100644 --- a/drivers/gpu/drm/i2c/tda998x_drv.c +++ b/drivers/gpu/drm/i2c/tda998x_drv.c @@ -1343,6 +1343,7 @@ static void tda998x_bridge_mode_set(struct drm_bridge *bridge, struct drm_display_mode *adjusted_mode) { struct tda998x_priv *priv = bridge_to_tda998x_priv(bridge); + unsigned long tmds_clock; u16 ref_pix, ref_line, n_pix, n_line; u16 hs_pix_s, hs_pix_e; u16 vs1_pix_s, vs1_pix_e, vs1_line_s, vs1_line_e; @@ -1413,12 +1414,19 @@ static void tda998x_bridge_mode_set(struct drm_bridge *bridge, (mode->vsync_end - mode->vsync_start)/2; } - div = 148500 / mode->clock; - if (div != 0) { - div--; - if (div > 3) - div = 3; - } + tmds_clock = mode->clock; + + /* + * The divisor is power-of-2. The TDA9983B datasheet gives + * this as ranges of Msample/s, which is 10x the TMDS clock: + * 0 - 800 to 1500 Msample/s + * 1 - 400 to 800 Msample/s + * 2 - 200 to 400 Msample/s + * 3 - as 2 above + */ + for (div = 0; div < 3; div++) + if (80000 >> div <= tmds_clock) + break; mutex_lock(&priv->audio_mutex); |