| Message ID | 20230427142934.55435-3-francesco@dolcini.it (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bridge: tc358768: various fixes on PLL calculation and DSI timings | expand |
On Thu, Apr 27, 2023 at 4:35 PM Francesco Dolcini <francesco@dolcini.it> wrote: > > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > 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> > --- > 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 8f349bf4fc32..e9e3f9e02bba 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) { > -- > 2.25.1 > Reviewed-by: Robert Foss <rfoss@kernel.org>
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index 8f349bf4fc32..e9e3f9e02bba 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) {