[PATCH v2 5/6] of_spi: Add fetching of of_gpio flags to of_spi_register_master

Andreas Larsson
2013-01-29T14:54:44Z

When using a gpio chip select with a OF_GPIO_ACTIVE_LOW flag, this needs to be
known to the controller driver.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
---
Documentation/devicetree/bindings/spi/spi-bus.txt | 3 +-
drivers/spi/spi.c | 24 ++++++++++++++++++--
include/linux/spi/spi.h | 5 ++++
3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
index 296015e..a4950a6 100644
--- a/Documentation/devicetree/bindings/spi/spi-bus.txt
+++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
@@ -57,7 +57,8 @@ contain the following properties.
3-wire mode.

If a gpio chipselect is used for the SPI slave the gpio number will be passed
-via the cs_gpio
+via the cs_gpio and the corresponding of_gpio_flags will be passed via
+cs_gpio_flags.

SPI example for an MPC5200 SPI bus:
spi@f00 {
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index a4baa0a..6f1b717 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -385,8 +385,10 @@ int spi_add_device(struct spi_device *spi)
goto done;
}

- if (master->cs_gpios)
+ if (master->cs_gpios) {
spi->cs_gpio = master->cs_gpios[spi->chip_select];
+ spi->cs_gpio_flags = master->cs_gpio_flags[spi->chip_select];
+ }

/* Drivers may modify this initial i/o setup, but will
* normally rely on the device being setup. Devices
@@ -1060,7 +1062,8 @@ EXPORT_SYMBOL_GPL(spi_alloc_master);
static int of_spi_register_master(struct spi_master *master)
{
int nb;
- int i, *cs;
+ int ret, i, *cs;
+ enum of_gpio_flags *flags;
struct device_node *np = master->dev.of_node;

if (!np)
@@ -1083,13 +1086,28 @@ static int of_spi_register_master(struct spi_master *master)
if (!master->cs_gpios)
return -ENOMEM;

+ flags = devm_kzalloc(&master->dev,
+ sizeof(*flags) * master->num_chipselect,
+ GFP_KERNEL);
+ master->cs_gpio_flags = flags;
+
+ if (!master->cs_gpio_flags) {
+ ret = -ENOMEM;
+ goto err_alloc_flags;
+ }
+
for (i = 0; i < master->num_chipselect; i++)
cs[i] = -EINVAL;

for (i = 0; i < nb; i++)
- cs[i] = of_get_named_gpio(np, "cs-gpios", i);
+ cs[i] = of_get_named_gpio_flags(np, "cs-gpios", i, &flags[i]);

return 0;
+
+err_alloc_flags:
+ devm_kfree(&master->dev, master->cs_gpios);
+ master->cs_gpios = NULL;
+ return ret;
}
#else
static int of_spi_register_master(struct spi_master *master)
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 88a669c..96b1055 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -23,6 +23,7 @@
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/kthread.h>
+#include <linux/of_gpio.h>

/*
* INTERFACES between SPI master-side drivers and SPI infrastructure.
@@ -58,6 +59,7 @@ extern struct bus_type spi_bus_type;
* 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_flags: of_gpio_flags corresponding to cs_gpio
*
* A @spi_device is used to interchange data between an SPI slave
* (usually a discrete chip) and CPU memory.
@@ -92,6 +94,7 @@ struct spi_device {
void *controller_data;
char modalias[SPI_NAME_SIZE];
int cs_gpio; /* chip select gpio */
+ enum of_gpio_flags cs_gpio_flags; /* chip select of_gpio_flags */

/*
* likely need more hooks for more protocol options affecting how
@@ -260,6 +263,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* 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_gpio_flags: possible array of of_gpio_flags corresponding to cs_gpios
*
* Each SPI master controller can communicate with one or more @spi_device
* children. These make a small bus, sharing MOSI, MISO and SCK signals
@@ -367,6 +371,7 @@ struct spi_master {
int (*unprepare_transfer_hardware)(struct spi_master *master);
/* gpio chip select */
int *cs_gpios;
+ enum of_gpio_flags *cs_gpio_flags;
};

static inline void *spi_master_get_devdata(struct spi_master *master)
--
1.7.0.4