Patch derived from one from Yakir Yang. Yakir Yang says:
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
However, avoid the ncts_atomic_write_bit and CTS_manual settings in this
patch, both of which are marked reserved in the iMX6 documentation. All
iMX6 code in the wild seems to want CTS_manual cleared.
Having requested clarification from FSL, it appears that neither of
these bits are implemented in their version of the IP.
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/bridge/dw_hdmi.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index b75922d4901e..cca1c3d165e2 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -182,20 +182,20 @@ static void hdmi_mask_writeb(struct dw_hdmi *hdmi, u8 data, unsigned int reg,
static void hdmi_set_cts_n(struct dw_hdmi *hdmi, unsigned int cts,
unsigned int n)
{
- hdmi_writeb(hdmi, n & 0xff, HDMI_AUD_N1);
- hdmi_writeb(hdmi, (n >> 8) & 0xff, HDMI_AUD_N2);
- hdmi_writeb(hdmi, (n >> 16) & 0x0f, HDMI_AUD_N3);
+ /* Must be set/cleared first */
+ hdmi_modb(hdmi, 0, HDMI_AUD_CTS3_CTS_MANUAL, HDMI_AUD_CTS3);
/* nshift factor = 0 */
hdmi_modb(hdmi, 0, HDMI_AUD_CTS3_N_SHIFT_MASK, HDMI_AUD_CTS3);
- /* 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);
- 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 >> 8) & 0xff, HDMI_AUD_CTS2);
+ hdmi_writeb(hdmi, cts & 0xff, HDMI_AUD_CTS1);
+
+ hdmi_writeb(hdmi, (n >> 16) & 0x0f, 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,
--
1.8.3.1
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