[PATCH 1/7] spi: Add support for device table matching

[Anton Vorontsov]

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@xxxxxxxxxxxxx>
---
 drivers/spi/spi.c               |   26 +++++++++++++++++++++++++-
 include/linux/mod_devicetable.h |   13 +++++++++++++
 include/linux/spi/spi.h         |   10 ++++++++--
 scripts/mod/file2alias.c        |   13 +++++++++++++
 4 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 70845cc..1431bf2 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -59,9 +59,24 @@ 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;
+}
+
 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;
 }
@@ -121,6 +136,13 @@ struct bus_type spi_bus_type = {
 };
 EXPORT_SYMBOL_GPL(spi_bus_type);
 
+static int spi_drv_probe_id(struct device *dev)
+{
+	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
+	struct spi_device		*sdev = to_spi_device(dev);
+
+	return sdrv->probe_id(sdev, spi_match_id(sdrv->id_table, sdev));
+}
 
 static int spi_drv_probe(struct device *dev)
 {
@@ -151,7 +173,9 @@ static void spi_drv_shutdown(struct device *dev)
 int spi_register_driver(struct spi_driver *sdrv)
 {
 	sdrv->driver.bus = &spi_bus_type;
-	if (sdrv->probe)
+	if (sdrv->probe_id)
+		sdrv->driver.probe = spi_drv_probe_id;
+	else if (sdrv->probe)
 		sdrv->driver.probe = spi_drv_probe;
 	if (sdrv->remove)
 		sdrv->driver.remove = spi_drv_remove;
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 1bf5900..9660dca 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -399,6 +399,19 @@ struct i2c_device_id {
 			__attribute__((aligned(sizeof(kernel_ulong_t))));
 };
 
+/* spi */
+
+#define SPI_NAME_SIZE	20
+
+struct spi_device_id {
+	char name[SPI_NAME_SIZE];
+#ifdef __KERNEL__
+	void *data;
+#else
+	kernel_ulong_t data;
+#endif
+};
+
 /* dmi */
 enum dmi_field {
 	DMI_NONE,
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index c47c4b4..c8d92a1 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 +146,8 @@ struct spi_message;
 
 /**
  * struct spi_driver - Host side "protocol" driver
+ * @id_table: List of SPI devices supported by this driver
+ * @probe_id: Binds this driver to the spi device via id_table matching.
  * @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 +173,9 @@ struct spi_message;
  * MMC, RTC, filesystem character device nodes, and hardware monitoring.
  */
 struct spi_driver {
+	const struct spi_device_id *id_table;
+	int			(*probe_id)(struct spi_device *spi,
+					    const struct spi_device_id *id);
 	int			(*probe)(struct spi_device *spi);
 	int			(*remove)(struct spi_device *spi);
 	void			(*shutdown)(struct spi_device *spi);
@@ -732,7 +738,7 @@ 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;
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 40e0045..9d446e3 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",
-- 
1.6.3.3

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