[PATCH 4.20 21/92] drm/bridge: tc358767: fix initial DP0/1_SRCCTRL value

From: Greg Kroah-Hartman
Date: Mon Feb 18 2019 - 09:46:29 EST


4.20-stable review patch. If anyone has any objections, please let me know.

------------------

[ Upstream commit 9a63bd6fe1b5590ffa42ae2ed22ee21363293e31 ]

Initially DP0_SRCCTRL is set to a static value which includes
DP0_SRCCTRL_LANES_2 and DP0_SRCCTRL_BW27, even when only 1 lane of
1.62Gbps speed is used. DP1_SRCCTRL is configured to a magic number.

This patch changes the configuration as follows:

Configure DP0_SRCCTRL by using tc_srcctrl() which provides the correct
value.

DP1_SRCCTRL needs two bits to be set to the same value as DP0_SRCCTRL:
SSCG and BW27. All other bits can be zero.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20190103115954.12785-5-tomi.valkeinen@xxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/bridge/tc358767.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index fee53422c31f..ab299f4debfa 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -836,12 +836,11 @@ static int tc_main_link_setup(struct tc_data *tc)
if (!tc->mode)
return -EINVAL;

- /* from excel file - DP0_SrcCtrl */
- tc_write(DP0_SRCCTRL, DP0_SRCCTRL_SCRMBLDIS | DP0_SRCCTRL_EN810B |
- DP0_SRCCTRL_LANESKEW | DP0_SRCCTRL_LANES_2 |
- DP0_SRCCTRL_BW27 | DP0_SRCCTRL_AUTOCORRECT);
- /* from excel file - DP1_SrcCtrl */
- tc_write(DP1_SRCCTRL, 0x00003083);
+ tc_write(DP0_SRCCTRL, tc_srcctrl(tc));
+ /* SSCG and BW27 on DP1 must be set to the same as on DP0 */
+ tc_write(DP1_SRCCTRL,
+ (tc->link.spread ? DP0_SRCCTRL_SSCG : 0) |
+ ((tc->link.base.rate != 162000) ? DP0_SRCCTRL_BW27 : 0));

rate = clk_get_rate(tc->refclk);
switch (rate) {
--
2.19.1