spi: spi-s3c64xx: Increase transfer timeout

Increase timeout by 30 ms for some wiggle room and set the minimum value
to 100 ms. This ensures a non-zero value for short transfers which
may take less than 1 ms. The timeout value does not affect
performance because it is used with a completion.

Similar formula is used in other drivers e.g. sun4i, sun6i.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Link: https://lore.kernel.org/r/20201002122243.26849-9-l.stelmach@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Łukasz Stelmach 2020-10-02 14:22:42 +02:00 committed by Mark Brown
parent 20b4016a3b
commit 9fe26adbe3
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@ -473,7 +473,8 @@ static int s3c64xx_wait_for_dma(struct s3c64xx_spi_driver_data *sdd,
/* millisecs to xfer 'len' bytes @ 'cur_speed' */
ms = xfer->len * 8 * 1000 / sdd->cur_speed;
ms += 10; /* some tolerance */
ms += 30; /* some tolerance */
ms = max(ms, 100); /* minimum timeout */
val = msecs_to_jiffies(ms) + 10;
val = wait_for_completion_timeout(&sdd->xfer_completion, val);