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of/spi: Support specifying chip select as active high via device tree

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

Signed-off-by: Wolfgang Ocker <weo@reccoware.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Wolfgang Ocker
2008-10-15 15:00:47 +02:00
committed by Kumar Gala
parent fd657efc67
commit f618ebfcbf
2 changed files with 4 additions and 0 deletions
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2
Documentation/powerpc/booting-without-of.txt
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@@ -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 {

2
drivers/of/of_spi.c
View File

@@ -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);