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Commit f618ebfc authored by Wolfgang Ocker's avatar Wolfgang Ocker Committed by Kumar Gala
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of/spi: Support specifying chip select as active high via device tree 



The patch allows to specify that an SPI device needs an active high chip
select.

Signed-off-by: default avatarWolfgang Ocker <weo@reccoware.de>
Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
parent fd657efc

Documentation/powerpc/booting-without-of.txt

+2 −0
Original line number Original line Diff line number Diff line
@@ -1917,6 +1917,8 @@ platforms are moved over to use the flattened-device-tree model. 
			inverse clock polarity (CPOL) mode

			inverse clock polarity (CPOL) mode

    - spi-cpha        - (optional) Empty property indicating device requires

    - spi-cpha        - (optional) Empty property indicating device requires

			shifted clock phase (CPHA) mode

			shifted clock phase (CPHA) mode

    - spi-cs-high     - (optional) Empty property indicating device requires

			chip select active high





    SPI example for an MPC5200 SPI bus:

    SPI example for an MPC5200 SPI bus:

		spi@f00 {

		spi@f00 {

drivers/of/of_spi.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -61,6 +61,8 @@ void of_register_spi_devices(struct spi_master *master, struct device_node *np) 
			spi->mode |= SPI_CPHA;

			spi->mode |= SPI_CPHA;

		if (of_find_property(nc, "spi-cpol", NULL))

		if (of_find_property(nc, "spi-cpol", NULL))

			spi->mode |= SPI_CPOL;

			spi->mode |= SPI_CPOL;

		if (of_find_property(nc, "spi-cs-high", NULL))

			spi->mode |= SPI_CS_HIGH;





		/* Device speed */

		/* Device speed */

		prop = of_get_property(nc, "spi-max-frequency", &len);

		prop = of_get_property(nc, "spi-max-frequency", &len);