Commit 56ede94a authored Aug 14, 2013 by Gabor Juhos Committed by Mark Brown Aug 14, 2013

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>

parent 24a0013a

drivers/spi/spi.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -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)

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