openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

spi: limit default transfer speed to controller's max speed 

Since the 'spi: Support transfer speed checking in the core'
change, the SPI core validates the desired speed of a given
transfer against the minimum and maximum speeds supported by
the controller.

If the speed of a transfer is not specified, the core uses
the maximum speed of the actual SPI device. However if the
maximum speed of the actual device is greater than the
maximum speed of the controller, the core will reject the
transfer due to the aforementioned change.

Change the code to use the maximum speed of the controller
by default if that is below the device's maximum speed.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Gabor Juhos 2013-08-14 10:25:28 +02:00 committed by Mark Brown
parent 24a0013a04
commit 56ede94a00
1 changed files with 6 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/spi/spi.c
View File

@ -1382,8 +1382,13 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
list_for_each_entry(xfer, &message->transfers, transfer_list) {
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->bits_per_word_mask) {
/* Only 32 bits fit in the mask */
if (xfer->bits_per_word > 32)