of: adapt of_find_i2c_driver() to be usable by SPI also

SPI has a similar problem as I2C in that it needs to determine an
appropriate modalias value for each device node.  This patch adapts
the of_i2c of_find_i2c_driver() function to be usable by of_spi also.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
index 344e1b0..6a98dc8 100644
--- a/drivers/of/of_i2c.c
+++ b/drivers/of/of_i2c.c
@@ -16,62 +16,6 @@
 #include <linux/of_i2c.h>
 #include <linux/module.h>
 
-struct i2c_driver_device {
-	char    *of_device;
-	char    *i2c_type;
-};
-
-static struct i2c_driver_device i2c_devices[] = {
-};
-
-static int of_find_i2c_driver(struct device_node *node,
-			      struct i2c_board_info *info)
-{
-	int i, cplen;
-	const char *compatible;
-	const char *p;
-
-	/* 1. search for exception list entry */
-	for (i = 0; i < ARRAY_SIZE(i2c_devices); i++) {
-		if (!of_device_is_compatible(node, i2c_devices[i].of_device))
-			continue;
-		if (strlcpy(info->type, i2c_devices[i].i2c_type,
-			    I2C_NAME_SIZE) >= I2C_NAME_SIZE)
-			return -ENOMEM;
-
-		return 0;
-	}
-
-	compatible = of_get_property(node, "compatible", &cplen);
-	if (!compatible)
-		return -ENODEV;
-
-	/* 2. search for linux,<i2c-type> entry */
-	p = compatible;
-	while (cplen > 0) {
-		if (!strncmp(p, "linux,", 6)) {
-			p += 6;
-			if (strlcpy(info->type, p,
-				    I2C_NAME_SIZE) >= I2C_NAME_SIZE)
-				return -ENOMEM;
-			return 0;
-		}
-
-		i = strlen(p) + 1;
-		p += i;
-		cplen -= i;
-	}
-
-	/* 3. take fist compatible entry and strip manufacturer */
-	p = strchr(compatible, ',');
-	if (!p)
-		return -ENODEV;
-	p++;
-	if (strlcpy(info->type, p, I2C_NAME_SIZE) >= I2C_NAME_SIZE)
-		return -ENOMEM;
-	return 0;
-}
-
 void of_register_i2c_devices(struct i2c_adapter *adap,
 			     struct device_node *adap_node)
 {
@@ -83,6 +27,9 @@
 		const u32 *addr;
 		int len;
 
+		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0)
+			continue;
+
 		addr = of_get_property(node, "reg", &len);
 		if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
 			printk(KERN_ERR
@@ -92,11 +39,6 @@
 
 		info.irq = irq_of_parse_and_map(node, 0);
 
-		if (of_find_i2c_driver(node, &info) < 0) {
-			irq_dispose_mapping(info.irq);
-			continue;
-		}
-
 		info.addr = *addr;
 
 		request_module(info.type);