atmel_spi: allow transfer when max_speed_hz = 0
For some reason I have to slowdown clock to touchscreen device.
In atmel_spi_setup() there is comment that max_speed_hz == 0 means as slow
as possible and divider is set to maximum value. But in
atmel_spi_transfer() function is check against not zero max_speed_hz with
EINVAL returned.
Probably driver should setup divider for each transfer based on
transfer->speed_hz value, but I think that would be not necessary overhead
as all used devices have constant clock.
Below patch works fine for me.
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 5e39bac..56ff3e6 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -670,8 +670,7 @@
dev_dbg(controller, "new message %p submitted for %s\n",
msg, spi->dev.bus_id);
- if (unlikely(list_empty(&msg->transfers)
- || !spi->max_speed_hz))
+ if (unlikely(list_empty(&msg->transfers)))
return -EINVAL;
if (as->stopping)