diff mbox series

[v2,8/9] spi: spi-s3c64xx: Increase transfer timeout

Message ID 20200821161401.11307-9-l.stelmach@samsung.com (mailing list archive)
State New, archived
Headers show
Series [v2,1/9] spi: spi-s3c64xx: swap s3c64xx_spi_set_cs() and s3c64xx_enable_datapath() | expand

Commit Message

Lukasz Stelmach Aug. 21, 2020, 4:14 p.m. UTC 
Increase timeout by 30 ms for some wiggle 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.

Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
---
 drivers/spi/spi-s3c64xx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Krzysztof Kozlowski Aug. 22, 2020, 12:43 p.m. UTC | #1 
On Fri, Aug 21, 2020 at 06:14:00PM +0200, Łukasz Stelmach wrote:
> Increase timeout by 30 ms for some wiggle 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.
> 
> Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
> ---
>  drivers/spi/spi-s3c64xx.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>

Best regards,
Krzysztof
diff mbox series

Patch

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 89c162efe355..ea5a22dec53d 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -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);