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 <[email protected]>
Cc: David Brownell <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Jean Delvare <[email protected]>
Cc: Ben Dooks <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index eb25ced..e2051f3 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 @@
 	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_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 @@
  * 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 @@
 	 * 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 @@
 		device_unregister(&spi->dev);
 }
 
+extern const struct spi_device_id *
+spi_get_device_id(const struct spi_device *sdev);
+
 #endif /* __LINUX_SPI_H */