[PATCH RFC] spi: core: Use master->max_speed_hz as transfer speed when xfer->speed_hz > master->max_speed_hz

[Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org>]

When xfer->speed_hz is greater than master->max_speed_hz, it's generally safe
to use master->max_speed_hz as transfer speed.
Thus use master->max_speed_hz as transfer speed rather than return error when
xfer->speed_hz > master->max_speed_hz.

Signed-off-by: Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org>
---
Hi Guenter,
Does this patch fix the issue you encounter?
Regards,
Axel
 drivers/spi/spi.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 454a523..26b331d 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1844,12 +1844,13 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 		message->frame_length += xfer->len;
 		if (!xfer->bits_per_word)
 			xfer->bits_per_word = spi->bits_per_word;
-		if (!xfer->speed_hz) {
+
+		if (!xfer->speed_hz)
 			xfer->speed_hz = spi->max_speed_hz;
-			if (master->max_speed_hz &&
-			    xfer->speed_hz > master->max_speed_hz)
-				xfer->speed_hz = master->max_speed_hz;
-		}
+
+		if (master->max_speed_hz &&
+		    xfer->speed_hz > master->max_speed_hz)
+			xfer->speed_hz = master->max_speed_hz;
 
 		if (master->bits_per_word_mask) {
 			/* Only 32 bits fit in the mask */
@@ -1878,9 +1879,6 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 		if (xfer->speed_hz && master->min_speed_hz &&
 		    xfer->speed_hz < master->min_speed_hz)
 			return -EINVAL;
-		if (xfer->speed_hz && master->max_speed_hz &&
-		    xfer->speed_hz > master->max_speed_hz)
-			return -EINVAL;
 
 		if (xfer->tx_buf && !xfer->tx_nbits)
 			xfer->tx_nbits = SPI_NBITS_SINGLE;
-- 
1.8.1.2



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