[PATCH v2 5/6] drm/bridge: tc358767: Set LSCLK divider for SYSCLK to 1

Marek Vasut marex at denx.de
Fri Jun 21 15:52:53 UTC 2024


The only information in the datasheet regarding this divider is a note
in SYS_PLLPARAM register documentation which states that when LSCLK is
270 MHz, LSCLK_DIV should be 1. What should LSCLK_DIV be set to when
LSCLK is 162 MHz (for DP 1.62G mode) is unclear, but empirical test
confirms using LSCLK_DIV 1 has no adverse effects either. In the worst
case, the internal TC358767 clock would run faster.

Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Andrzej Hajda <andrzej.hajda at intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: David Airlie <airlied at gmail.com>
Cc: Jernej Skrabec <jernej.skrabec at gmail.com>
Cc: Jonas Karlman <jonas at kwiboo.se>
Cc: Laurent Pinchart <Laurent.pinchart at ideasonboard.com>
Cc: Lucas Stach <l.stach at pengutronix.de>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Neil Armstrong <neil.armstrong at linaro.org>
Cc: Robert Foss <rfoss at kernel.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Cc: dri-devel at lists.freedesktop.org
Cc: kernel at dh-electronics.com
---
V2: No change
---
 drivers/gpu/drm/bridge/tc358767.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index a48454fe2f634..743bf1334923d 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -738,7 +738,7 @@ static int tc_stream_clock_calc(struct tc_data *tc)
 static int tc_set_syspllparam(struct tc_data *tc)
 {
 	unsigned long rate;
-	u32 pllparam = SYSCLK_SEL_LSCLK | LSCLK_DIV_2;
+	u32 pllparam = SYSCLK_SEL_LSCLK | LSCLK_DIV_1;
 
 	rate = clk_get_rate(tc->refclk);
 	switch (rate) {
-- 
2.43.0



More information about the dri-devel mailing list