On 14.11.2018 16:14, Andrzej Hajda wrote: > On 14.11.2018 12:17, Linus Walleij wrote: >> After adding the hs_rate and lp_rate fields to the DSI device >> we need to populate these accordingly so display drivers can >> respect them. >> >> This figure for HS rate comes from the ILI9881C manual, the >> calculation is explained in the comment. >> >> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> >> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx> >> Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxx> >> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> >> --- >> drivers/gpu/drm/panel/panel-ilitek-ili9881c.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c >> index 3ad4a46c4e94..f58250f84f8c 100644 >> --- a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c >> +++ b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c >> @@ -465,6 +465,13 @@ static int ili9881c_dsi_probe(struct mipi_dsi_device *dsi) >> dsi->mode_flags = MIPI_DSI_MODE_VIDEO_SYNC_PULSE; >> dsi->format = MIPI_DSI_FMT_RGB888; >> dsi->lanes = 4; >> + /* >> + * The datasheet (table 39) specifies "limited clock channel speed" >> + * for 4 lanes as 550 Mbps for RGB888. As this is 4 bits at the time, >> + * the maximum HS frequency is 550/4 = 137.5 MHz. >> + */ >> + dsi->hs_rate = 137500000; >> + /* FIXME: LP max rate does not seem to be specified */ >> >> return mipi_dsi_attach(dsi); >> } > Table 42 says: "Length of LP-00, LP-01, LP-10 or LP-11 periods": min > 50ns, max 75ns. > > 1/50ns = max LPM rate = 20.000.000Hz ...and since in LP transmission there are two periods per bit it should be divided by 2. So max LPM rate shall be 10.000.000Hz - anyway it would be good if somebody verifies it. Regards Andrzej > > > Regards > > Andrzej > > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
