[PATCH] drm/bridge: tc358767: Limit the Pixel PLL input range

[Marek Vasut]

According to new configuration spreadsheet from Toshiba for TC9595,
the Pixel PLL input clock have to be in range 6..40 MHz. The sheet
calculates those PLL input clock as reference clock divided by both
pre-dividers. Add the extra limit.

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: Neil Armstrong <neil.armstrong at linaro.org>
Cc: Robert Foss <rfoss at kernel.org>
Cc: dri-devel at lists.freedesktop.org
---
 drivers/gpu/drm/bridge/tc358767.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 615cc8f950d7b..0c29a8f81cc9e 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -546,9 +546,14 @@ static int tc_pxl_pll_en(struct tc_data *tc, u32 refclk, u32 pixelclock)
 			continue;
 		for (i_post = 0; i_post < ARRAY_SIZE(ext_div); i_post++) {
 			for (div = 1; div <= 16; div++) {
-				u32 clk;
+				u32 clk, iclk;
 				u64 tmp;
 
+				/* PCLK PLL input unit clock ... 6..40 MHz */
+				iclk = refclk / (div * ext_div[i_pre]);
+				if (iclk < 6000000 || iclk > 40000000)
+					continue;
+
 				tmp = pixelclock * ext_div[i_pre] *
 				      ext_div[i_post] * div;
 				do_div(tmp, refclk);
-- 
2.43.0