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authorGrant Likely <grant.likely@secretlab.ca>2008-05-16 11:37:09 -0600
committerGrant Likely <grant.likely@secretlab.ca>2008-07-25 22:34:40 -0400
commit284b01897340974000bcc84de87a4e1becc8a83d (patch)
tree9d2f38c9d2d39601d615f738c337c5af14a6b344 /drivers
parentdc87c98e8f635a718f1abb2c3e15fc77c0001651 (diff)
downloadop-kernel-dev-284b01897340974000bcc84de87a4e1becc8a83d.zip
op-kernel-dev-284b01897340974000bcc84de87a4e1becc8a83d.tar.gz
spi: Add OF binding support for SPI busses
This patch adds support for populating an SPI bus based on data in the OF device tree. This is useful for powerpc platforms which use the device tree instead of discrete code for describing platform layout. Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/of/Kconfig6
-rw-r--r--drivers/of/Makefile1
-rw-r--r--drivers/of/of_spi.c93
3 files changed, 100 insertions, 0 deletions
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 1d7ec31..f821dbc 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -13,3 +13,9 @@ config OF_I2C
depends on PPC_OF && I2C
help
OpenFirmware I2C accessors
+
+config OF_SPI
+ def_tristate SPI
+ depends on OF && PPC_OF && SPI
+ help
+ OpenFirmware SPI accessors
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 548772e..4c3c6f8 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -2,3 +2,4 @@ obj-y = base.o
obj-$(CONFIG_OF_DEVICE) += device.o platform.o
obj-$(CONFIG_OF_GPIO) += gpio.o
obj-$(CONFIG_OF_I2C) += of_i2c.o
+obj-$(CONFIG_OF_SPI) += of_spi.o
diff --git a/drivers/of/of_spi.c b/drivers/of/of_spi.c
new file mode 100644
index 0000000..b01eec0
--- /dev/null
+++ b/drivers/of/of_spi.c
@@ -0,0 +1,93 @@
+/*
+ * SPI OF support routines
+ * Copyright (C) 2008 Secret Lab Technologies Ltd.
+ *
+ * Support routines for deriving SPI device attachments from the device
+ * tree.
+ */
+
+#include <linux/of.h>
+#include <linux/device.h>
+#include <linux/spi/spi.h>
+#include <linux/of_spi.h>
+
+/**
+ * of_register_spi_devices - Register child devices onto the SPI bus
+ * @master: Pointer to spi_master device
+ * @np: parent node of SPI device nodes
+ *
+ * Registers an spi_device for each child node of 'np' which has a 'reg'
+ * property.
+ */
+void of_register_spi_devices(struct spi_master *master, struct device_node *np)
+{
+ struct spi_device *spi;
+ struct device_node *nc;
+ const u32 *prop;
+ int rc;
+ int len;
+
+ for_each_child_of_node(np, nc) {
+ /* Alloc an spi_device */
+ spi = spi_alloc_device(master);
+ if (!spi) {
+ dev_err(&master->dev, "spi_device alloc error for %s\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+
+ /* Select device driver */
+ if (of_modalias_node(nc, spi->modalias,
+ sizeof(spi->modalias)) < 0) {
+ dev_err(&master->dev, "cannot find modalias for %s\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+
+ /* Device address */
+ prop = of_get_property(nc, "reg", &len);
+ if (!prop || len < sizeof(*prop)) {
+ dev_err(&master->dev, "%s has no 'reg' property\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+ spi->chip_select = *prop;
+
+ /* Mode (clock phase/polarity/etc.) */
+ if (of_find_property(nc, "spi-cpha", NULL))
+ spi->mode |= SPI_CPHA;
+ if (of_find_property(nc, "spi-cpol", NULL))
+ spi->mode |= SPI_CPOL;
+
+ /* Device speed */
+ prop = of_get_property(nc, "spi-max-frequency", &len);
+ if (!prop || len < sizeof(*prop)) {
+ dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ continue;
+ }
+ spi->max_speed_hz = *prop;
+
+ /* IRQ */
+ spi->irq = irq_of_parse_and_map(nc, 0);
+
+ /* Store a pointer to the node in the device structure */
+ of_node_get(nc);
+ spi->dev.archdata.of_node = nc;
+
+ /* Register the new device */
+ request_module(spi->modalias);
+ rc = spi_add_device(spi);
+ if (rc) {
+ dev_err(&master->dev, "spi_device register error %s\n",
+ nc->full_name);
+ spi_dev_put(spi);
+ }
+
+ }
+}
+EXPORT_SYMBOL(of_register_spi_devices);
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