spi: add support for device table matching

With this patch spi drivers can use standard spi_driver.id_table and
MODULE_DEVICE_TABLE() mechanisms to bind against the devices.  Just like
we do with I2C drivers.

This is useful when a single driver supports several variants of devices
but it is not possible to detect them in run-time (like non-JEDEC chips
probing in drivers/mtd/devices/m25p80.c), and when platform_data usage is
overkill.

This patch also makes life a lot easier on OpenFirmware platforms, since
with OF we extensively use proper device IDs in modaliases.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 54 insertions, 2 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 70845ccd85c3..8518a6eb63f3 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -59,9 +59,32 @@ static struct device_attribute spi_dev_attrs[] = {
  * and the sysfs version makes coldplug work too.
  */
 
+static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
+                                                const struct spi_device *sdev)
+{
+        while (id->name[0]) {
+                if (!strcmp(sdev->modalias, id->name))
+                        return id;
+                id++;
+        }
+        return NULL;
+}
+
+const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
+{
+        const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
+
+        return spi_match_id(sdrv->id_table, sdev);
+}
+EXPORT_SYMBOL_GPL(spi_get_device_id);
+
 static int spi_match_device(struct device *dev, struct device_driver *drv)
 {
         const struct spi_device *spi = to_spi_device(dev);
+        const struct spi_driver *sdrv = to_spi_driver(drv);
+
+        if (sdrv->id_table)
+                return !!spi_match_id(sdrv->id_table, spi);
 
         return strcmp(spi->modalias, drv->name) == 0;
 }
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 1bf5900ffe43..b34f1ef2f1fe 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -399,6 +399,16 @@ struct i2c_device_id {
                         __attribute__((aligned(sizeof(kernel_ulong_t))));
 };
 
+/* spi */
+
+#define SPI_NAME_SIZE   32
+
+struct spi_device_id {
+        char name[SPI_NAME_SIZE];
+        kernel_ulong_t driver_data      /* Data private to the driver */
+                        __attribute__((aligned(sizeof(kernel_ulong_t))));
+};
+
 /* dmi */
 enum dmi_field {
         DMI_NONE,
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index eb25cedb995b..e2051f39f6a8 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -20,6 +20,7 @@
 #define __LINUX_SPI_H
 
 #include <linux/device.h>
+#include <linux/mod_devicetable.h>
 
 /*
  * INTERFACES between SPI master-side drivers and SPI infrastructure.
@@ -86,7 +87,7 @@ struct spi_device {
         int                     irq;
         void                    *controller_state;
         void                    *controller_data;
-        char                    modalias[32];
+        char                    modalias[SPI_NAME_SIZE];
 
         /*
          * likely need more hooks for more protocol options affecting how
@@ -145,6 +146,7 @@ struct spi_message;
 
 /**
  * struct spi_driver - Host side "protocol" driver
+ * @id_table: List of SPI devices supported by this driver
  * @probe: Binds this driver to the spi device.  Drivers can verify
  *      that the device is actually present, and may need to configure
  *      characteristics (such as bits_per_word) which weren't needed for
@@ -170,6 +172,7 @@ struct spi_message;
  * MMC, RTC, filesystem character device nodes, and hardware monitoring.
  */
 struct spi_driver {
+        const struct spi_device_id *id_table;
         int                     (*probe)(struct spi_device *spi);
         int                     (*remove)(struct spi_device *spi);
         void                    (*shutdown)(struct spi_device *spi);
@@ -734,7 +737,7 @@ struct spi_board_info {
          * controller_data goes to spi_device.controller_data,
          * irq is copied too
          */
-        char            modalias[32];
+        char            modalias[SPI_NAME_SIZE];
         const void      *platform_data;
         void            *controller_data;
         int             irq;
@@ -802,4 +805,7 @@ spi_unregister_device(struct spi_device *spi)
                 device_unregister(&spi->dev);
 }
 
+extern const struct spi_device_id *
+spi_get_device_id(const struct spi_device *sdev);
+
 #endif /* __LINUX_SPI_H */
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 40e0045876ee..9d446e34519c 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -657,6 +657,15 @@ static int do_i2c_entry(const char *filename, struct i2c_device_id *id,
         return 1;
 }
 
+/* Looks like: S */
+static int do_spi_entry(const char *filename, struct spi_device_id *id,
+                        char *alias)
+{
+        sprintf(alias, "%s", id->name);
+
+        return 1;
+}
+
 static const struct dmifield {
         const char *prefix;
         int field;
@@ -853,6 +862,10 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
                 do_table(symval, sym->st_size,
                          sizeof(struct i2c_device_id), "i2c",
                          do_i2c_entry, mod);
+        else if (sym_is(symname, "__mod_spi_device_table"))
+                do_table(symval, sym->st_size,
+                         sizeof(struct spi_device_id), "spi",
+                         do_spi_entry, mod);
         else if (sym_is(symname, "__mod_dmi_device_table"))
                 do_table(symval, sym->st_size,
                          sizeof(struct dmi_system_id), "dmi",