[PATCH v2 6/6] of_spi: Initialize cs_gpios and cs_gpio with -EEXIST

Andreas Larsson
2013-01-29T14:53:59Z

Holes in the cs-gpios DT phandle list is supposed to mark that native
chipselects is to be used. The value returned from of_get_named_gpio_flags in
this case is -EEXIST. By initializing cs_gpios and cs_gpio with -EEXIST, this
and only this errno will indicate to a spi controller driver that a native
chipselect is to be used.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
---
drivers/spi/spi.c | 4 ++--
include/linux/spi/spi.h | 7 +++++--
2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6f1b717..7494bad 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -334,7 +334,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master)
spi->dev.parent = &master->dev;
spi->dev.bus = &spi_bus_type;
spi->dev.release = spidev_release;
- spi->cs_gpio = -EINVAL;
+ spi->cs_gpio = -EEXIST;
device_initialize(&spi->dev);
return spi;
}
@@ -1097,7 +1097,7 @@ static int of_spi_register_master(struct spi_master *master)
}

for (i = 0; i < master->num_chipselect; i++)
- cs[i] = -EINVAL;
+ cs[i] = -EEXIST;

for (i = 0; i < nb; i++)
cs[i] = of_get_named_gpio_flags(np, "cs-gpios", i, &flags[i]);
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 96b1055..0701882 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -58,7 +58,8 @@ extern struct bus_type spi_bus_type;
* @modalias: Name of the driver to use with this device, or an alias
* for that name. This appears in the sysfs "modalias" attribute
* for driver coldplugging, and in uevents used for hotplugging
- * @cs_gpio: Negative or gpio for chip select.
+ * @cs_gpio: Negative or gpio for chip select. Set to -EEXIST when chipselect
+ * should be handled natively by the controller driver
* @cs_gpio_flags: of_gpio_flags corresponding to cs_gpio
*
* A @spi_device is used to interchange data between an SPI slave
@@ -262,7 +263,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* @unprepare_transfer_hardware: there are currently no more messages on the
* queue so the subsystem notifies the driver that it may relax the
* hardware by issuing this call
- * @cs_gpios: possible array of negative values or gpios for chip selects
+ * @cs_gpios: possible array of negative values or gpios for chip selects. A
+ * chipselect that should be handled natively by the controller driver is
+ * set to -EEXIST.
* @cs_gpio_flags: possible array of of_gpio_flags corresponding to cs_gpios
*
* Each SPI master controller can communicate with one or more @spi_device
--
1.7.0.4