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Subject[PATCH 1/5] Implement module aliasing for i2c to translate from device tree names
This patch allows new style i2c chip drivers to have alias names using
the official kernel aliasing system and MODULE_DEVICE_TABLE(). I've
tested it on PowerPC and x86. This change is required for PowerPC
device tree support.

Signed-off-by: Jon Smirl <jonsmirl@gmail.com>
---
drivers/i2c/i2c-core.c | 32 ++++++++++++++++++++++++++------
include/linux/i2c.h | 9 ++++-----
include/linux/mod_devicetable.h | 20 ++++++++++++++++++++
scripts/mod/file2alias.c | 19 +++++++++++++++++++
4 files changed, 69 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index b5e13e4..fce06fd 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -47,10 +47,25 @@ static DEFINE_IDR(i2c_adapter_idr);

/* ------------------------------------------------------------------------- */

-static int i2c_device_match(struct device *dev, struct device_driver *drv)
+static const struct i2c_device_id *i2c_device_match(const struct i2c_device_id *id, struct i2c_client *client)
+{
+ /* only powerpc drivers implement the id_table,
+ * it is empty on other platforms */
+ if (id) {
+ while (id->name[0]) {
+ if (strcmp(client->driver_name, id->name) == 0)
+ return id;
+ id++;
+ }
+ }
+ return NULL;
+}
+
+static int i2c_bus_match(struct device *dev, struct device_driver *drv)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_driver *driver = to_i2c_driver(drv);
+ const struct i2c_device_id *found_id;

/* make legacy i2c drivers bypass driver model probing entirely;
* such drivers scan each i2c adapter/bus themselves.
@@ -58,9 +73,11 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
if (!is_newstyle_driver(driver))
return 0;

- /* new style drivers use the same kind of driver matching policy
- * as platform devices or SPI: compare device and driver IDs.
- */
+ /* match on an id table if there is one */
+ found_id = i2c_device_match(driver->id_table, client);
+ if (found_id)
+ return 1;
+
return strcmp(client->driver_name, drv->name) == 0;
}

@@ -89,12 +106,15 @@ static int i2c_device_probe(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_driver *driver = to_i2c_driver(dev->driver);
+ const struct i2c_device_id *id;

if (!driver->probe)
return -ENODEV;
client->driver = driver;
dev_dbg(dev, "probe\n");
- return driver->probe(client);
+
+ id = i2c_device_match(driver->id_table, client);
+ return driver->probe(client, id);
}

static int i2c_device_remove(struct device *dev)
@@ -189,7 +209,7 @@ static struct device_attribute i2c_dev_attrs[] = {
static struct bus_type i2c_bus_type = {
.name = "i2c",
.dev_attrs = i2c_dev_attrs,
- .match = i2c_device_match,
+ .match = i2c_bus_match,
.uevent = i2c_device_uevent,
.probe = i2c_device_probe,
.remove = i2c_device_remove,
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index a100c9f..49fc682 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -126,7 +126,7 @@ struct i2c_driver {
* With the driver model, device enumeration is NEVER done by drivers;
* it's done by infrastructure. (NEW STYLE DRIVERS ONLY)
*/
- int (*probe)(struct i2c_client *);
+ int (*probe)(struct i2c_client *, const struct i2c_device_id *id);
int (*remove)(struct i2c_client *);

/* driver model interfaces that don't relate to enumeration */
@@ -141,11 +141,10 @@ struct i2c_driver {

struct device_driver driver;
struct list_head list;
+ struct i2c_device_id *id_table;
};
#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)

-#define I2C_NAME_SIZE 20
-
/**
* struct i2c_client - represent an I2C slave device
* @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
@@ -179,7 +178,7 @@ struct i2c_client {
/* to the client */
struct device dev; /* the device structure */
int irq; /* irq issued by device (or -1) */
- char driver_name[KOBJ_NAME_LEN];
+ char driver_name[I2C_NAME_SIZE];
struct list_head list;
struct completion released;
};
@@ -223,7 +222,7 @@ static inline void i2c_set_clientdata (struct i2c_client *dev, void *data)
* with the adapter already known.
*/
struct i2c_board_info {
- char driver_name[KOBJ_NAME_LEN];
+ char driver_name[I2C_NAME_SIZE];
char type[I2C_NAME_SIZE];
unsigned short flags;
unsigned short addr;
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index e9fddb4..d66038a 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -367,4 +367,24 @@ struct virtio_device_id {
};
#define VIRTIO_DEV_ANY_ID 0xffffffff

+/* i2c */
+
+/* These defines are used to separate PowerPC open firmware
+ * drivers into their own namespace */
+#define I2C_NAME_SIZE (16*3)
+#define I2C_MODULE_PREFIX "i2c:N"
+#ifdef CONFIG_OF
+#define OF_I2C_PREFIX "OF,"
+#define I2C_OF_MODULE_PREFIX I2C_MODULE_PREFIX OF_I2C_PREFIX
+#define OF_I2C_ID(s,d) {OF_I2C_PREFIX s, (d) },
+#else
+#define OF_I2C_ID(s,d)
+#endif
+
+struct i2c_device_id {
+ char name[I2C_NAME_SIZE];
+ kernel_ulong_t driver_data; /* Data private to the driver */
+};
+
+
#endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index d802b5a..da43742 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -539,6 +539,21 @@ static int do_virtio_entry(const char *filename, struct virtio_device_id *id,
return 1;
}

+/* Looks like: i2c:Ns */
+static int do_i2c_entry(const char *filename, struct i2c_device_id *id,
+ char *alias)
+{
+ char *tmp;
+ sprintf (alias, I2C_MODULE_PREFIX "%s", id->name);
+
+ /* Replace all whitespace with underscores */
+ for (tmp = alias; tmp && *tmp; tmp++)
+ if (isspace (*tmp))
+ *tmp = '_';
+
+ return 1;
+}
+
/* Ignore any prefix, eg. v850 prepends _ */
static inline int sym_is(const char *symbol, const char *name)
{
@@ -669,6 +684,10 @@ void handle_moddevtable(struct module *mod, struct elf_info *info,
do_table(symval, sym->st_size,
sizeof(struct virtio_device_id), "virtio",
do_virtio_entry, mod);
+ else if (sym_is(symname, "__mod_i2c_device_table"))
+ do_table(symval, sym->st_size,
+ sizeof(struct i2c_device_id), "i2c",
+ do_i2c_entry, mod);
free(zeros);
}



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