drm/bridge: tc358768: fix PLL parameters computation

[ Upstream commit 6a4020b4c63911977aaf8047f904a300d15de739 ]

According to Toshiba documentation the PLL input clock after the divider
should be not less than 4MHz, fix the PLL parameters computation
accordingly.

Fixes: ff1ca6397b ("drm/bridge: Add tc358768 driver")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-3-francesco@dolcini.it
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Francesco Dolcini 2023-04-27 16:29:27 +02:00 committed by Greg Kroah-Hartman
parent 1b4f23fdf2
commit 825b00c685

View File

@ -329,13 +329,17 @@ static int tc358768_calc_pll(struct tc358768_priv *priv,
u32 fbd;
for (fbd = 0; fbd < 512; ++fbd) {
u32 pll, diff;
u32 pll, diff, pll_in;
pll = (u32)div_u64((u64)refclk * (fbd + 1), divisor);
if (pll >= max_pll || pll < min_pll)
continue;
pll_in = (u32)div_u64((u64)refclk, prd + 1);
if (pll_in < 4000000)
continue;
diff = max(pll, target_pll) - min(pll, target_pll);
if (diff < best_diff) {