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>

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;
 }

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,

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 */

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",