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Subject[PATCH v3 1/4] of: adapt of_find_i2c_driver() to be usable by SPI also
Date
From: Grant Likely <grant.likely@secretlab.ca>

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>
---
drivers/of/base.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++
drivers/of/of_i2c.c | 64 ++-----------------------------------
include/linux/of.h | 1 +
3 files changed, 92 insertions(+), 61 deletions(-)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 23ffb7c..ad8ac1a 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -385,3 +385,91 @@ struct device_node *of_find_matching_node(struct device_node *from,
return np;
}
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[] = {
+ /* Empty for now; add entries as needed */
+};
+
+/**
+ * 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. Three
+ * separate methods are used to derive a modalias value.
+ *
+ * First method is to lookup the compatible value in of_modalias_table.
+ * Second is to look for a "linux,<modalias>" entry in the compatible list
+ * and used that for modalias. Third is to strip off the manufacturer
+ * prefix from the first compatible entry and use the remainder as modalias
+ *
+ * This routine returns 0 on success
+ */
+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;
+ }
+
+ compatible = of_get_property(node, "compatible", &cplen);
+ if (!compatible)
+ return -ENODEV;
+
+ /* 2. search for linux,<modalias> entry */
+ p = compatible;
+ while (cplen > 0) {
+ if (!strncmp(p, "linux,", 6)) {
+ p += 6;
+ strlcpy(modalias, p, len);
+ return 0;
+ }
+
+ i = strlen(p) + 1;
+ p += i;
+ cplen -= i;
+ }
+
+ /* 3. take first compatible entry and strip manufacturer */
+ p = strchr(compatible, ',');
+ if (!p)
+ return -ENODEV;
+ p++;
+ strlcpy(modalias, p, len);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_modalias_node);
+
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 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
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 @@ void of_register_i2c_devices(struct i2c_adapter *adap,

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);
diff --git a/include/linux/of.h b/include/linux/of.h
index 59a61bd..79886ad 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -70,5 +70,6 @@ extern int of_n_addr_cells(struct device_node *np);
extern int of_n_size_cells(struct device_node *np);
extern const struct of_device_id *of_match_node(
const struct of_device_id *matches, const struct device_node *node);
+extern int of_modalias_node(struct device_node *node, char *modalias, int len);

#endif /* _LINUX_OF_H */


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