From: Francesco Dolcini francesco.dolcini@toradex.com
[ 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: ff1ca6397b1d ("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-frances... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/bridge/tc358768.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index 8f349bf4fc32f..e9e3f9e02bba0 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -334,13 +334,17 @@ 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) {