[PATCH] spi: core: Set max_speed_hz of spi_device default to max_speed_hz of controller

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

In __spi_validate(), xfer->speed_hz is set to be spi->max_speed_hz if it is not
set for this transfer. However, if spi->max_speed_hz is also not set,
xfer->speed_hz is 0. Some drivers (e.g. au1550, tegra114, tegra20-sflash,
tegra20-slink, etc.) then use below code to avoid setting xfer->speed_hz to 0.

        /* Set speed to the spi max fequency if spi device has not set */
        spi->max_speed_hz = spi->max_speed_hz ? : tspi->spi_max_frequency;

Let's handle it in spi core.
If spi->max_speed_hz is not set, make it default to spi->master->max_speed_hz.
So In __spi_validate() if both xfer->speed_hz and spi->max_speed_hz are not set,
xfer->speed_hz will be set to spi->master->max_speed_hz.

Signed-off-by: Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org>
---
 drivers/spi/spi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index d51f2a3..1c9ddf1 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1787,6 +1787,9 @@ int spi_setup(struct spi_device *spi)
 	if (!spi->bits_per_word)
 		spi->bits_per_word = 8;
 
+	if (!spi->max_speed_hz)
+		spi->max_speed_hz = spi->master->max_speed_hz;
+
 	if (spi->master->setup)
 		status = spi->master->setup(spi);
 
-- 
1.8.1.2



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