of: refactor of_modalias_node() and remove explicit match table.

This patch tightens up the behaviour of of_modalias_node() to be more
predicatable and to eliminate the explicit of_modalias_tablep[] that
is currently used to override the first entry in the compatible list
of a device.  The override table was needed originally because spi
and i2c drivers had no way to do of-style matching.  Now that all
devices can have an of_node pointer, and all drivers can have an
of_match_table, the explicit override table is no longer needed
because each driver can specify its own OF-style match data.

The mpc8349emitx-mcu driver is modified to explicitly specify the
correct device to bind against.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 9 insertions, 55 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index b5ad9740d8b2..e3f7af882e45 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -545,74 +545,28 @@ struct device_node *of_find_matching_node(struct device_node *from,
 EXPORT_SYMBOL(of_find_matching_node);
 
 /**
- * of_modalias_table: Table of explicit compatible ==> modalias mappings
- *
- * This table allows particulare compatible property values to be mapped
- * to modalias strings.  This is useful for busses which do not directly
- * understand the OF device tree but are populated based on data contained
- * within the device tree.  SPI and I2C are the two current users of this
- * table.
- *
- * In most cases, devices do not need to be listed in this table because
- * the modalias value can be derived directly from the compatible table.
- * However, if for any reason a value cannot be derived, then this table
- * provides a method to override the implicit derivation.
- *
- * At the moment, a single table is used for all bus types because it is
- * assumed that the data size is small and that the compatible values
- * should already be distinct enough to differentiate between SPI, I2C
- * and other devices.
- */
-struct of_modalias_table {
-        char *of_device;
-        char *modalias;
-};
-static struct of_modalias_table of_modalias_table[] = {
-        { "fsl,mcu-mpc8349emitx", "mcu-mpc8349emitx" },
-        { "mmc-spi-slot", "mmc_spi" },
-};
-
-/**
  * of_modalias_node - Lookup appropriate modalias for a device node
  * @node:       pointer to a device tree node
  * @modalias:   Pointer to buffer that modalias value will be copied into
  * @len:        Length of modalias value
  *
- * Based on the value of the compatible property, this routine will determine
- * an appropriate modalias value for a particular device tree node.  Two
- * separate methods are attempted to derive a modalias value.
+ * Based on the value of the compatible property, this routine will attempt
+ * to choose an appropriate modalias value for a particular device tree node.
+ * It does this by stripping the manufacturer prefix (as delimited by a ',')
+ * from the first entry in the compatible list property.
  *
- * First method is to lookup the compatible value in of_modalias_table.
- * Second is to strip off the manufacturer prefix from the first
- * compatible entry and use the remainder as modalias
- *
- * This routine returns 0 on success
+ * This routine returns 0 on success, <0 on failure.
  */
 int of_modalias_node(struct device_node *node, char *modalias, int len)
 {
-        int i, cplen;
-        const char *compatible;
-        const char *p;
-
-        /* 1. search for exception list entry */
-        for (i = 0; i < ARRAY_SIZE(of_modalias_table); i++) {
-                compatible = of_modalias_table[i].of_device;
-                if (!of_device_is_compatible(node, compatible))
-                        continue;
-                strlcpy(modalias, of_modalias_table[i].modalias, len);
-                return 0;
-        }
+        const char *compatible, *p;
+        int cplen;
 
         compatible = of_get_property(node, "compatible", &cplen);
-        if (!compatible)
+        if (!compatible || strlen(compatible) > cplen)
                 return -ENODEV;
-
-        /* 2. take first compatible entry and strip manufacturer */
         p = strchr(compatible, ',');
-        if (!p)
-                return -ENODEV;
-        p++;
-        strlcpy(modalias, p, len);
+        strlcpy(modalias, p ? p + 1 : compatible, len);
         return 0;
 }
 EXPORT_SYMBOL_GPL(of_modalias_node);