5.4-stable review patch. If anyone has any objections, please let me know.
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From: Dave Stevenson dave.stevenson@raspberrypi.com
[ Upstream commit 86addd25314a1e77dbdcfddfeed0bab2f27da0e2 ]
The existing fixed value of 16 worked for UYVY 720P60 over 2 lanes at 594MHz, or UYVY 1080P60 over 4 lanes. (RGB888 1080P60 needs 6 lanes at 594MHz). It doesn't allow for lower resolutions to work as the FIFO underflows.
374 is required for 1080P24 or 1080P30 UYVY over 2 lanes @ 972Mbit/s, but >374 means that the FIFO underflows on 1080P50 UYVY over 2 lanes @ 972Mbit/s.
Whilst it would be nice to compute it, the required information isn't published by Toshiba.
Signed-off-by: Dave Stevenson dave.stevenson@raspberrypi.com Signed-off-by: Hans Verkuil hverkuil@xs4all.nl Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/i2c/tc358743.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/media/i2c/tc358743.c b/drivers/media/i2c/tc358743.c index 26e9e95dd6ae..2dad35568586 100644 --- a/drivers/media/i2c/tc358743.c +++ b/drivers/media/i2c/tc358743.c @@ -1959,8 +1959,19 @@ static int tc358743_probe_of(struct tc358743_state *state) state->pdata.refclk_hz = clk_get_rate(refclk); state->pdata.ddc5v_delay = DDC5V_DELAY_100_MS; state->pdata.enable_hdcp = false; - /* A FIFO level of 16 should be enough for 2-lane 720p60 at 594 MHz. */ - state->pdata.fifo_level = 16; + /* + * Ideally the FIFO trigger level should be set based on the input and + * output data rates, but the calculations required are buried in + * Toshiba's register settings spreadsheet. + * A value of 16 works with a 594Mbps data rate for 720p60 (using 2 + * lanes) and 1080p60 (using 4 lanes), but fails when the data rate + * is increased, or a lower pixel clock is used that result in CSI + * reading out faster than the data is arriving. + * + * A value of 374 works with both those modes at 594Mbps, and with most + * modes on 972Mbps. + */ + state->pdata.fifo_level = 374; /* * The PLL input clock is obtained by dividing refclk by pll_prd. * It must be between 6 MHz and 40 MHz, lower frequency is better.