Commit dde67eb1beeb ("i2c: add i2c_get_device_id() to get the standard
I2C device id") added a function to return the standard I2C device ID.
Use that function to verify the device ID of a given device.
Cc: Peter Rosin <peda@xxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
RFC:
- Compile tested only
- Should there also be I2C_DEVICE_PART_ID_ANY to enable maching
against all parts from a given manufacturer ?
drivers/i2c/i2c-core-base.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/i2c.h | 3 +++
2 files changed, 37 insertions(+)
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 16a3b73375a6..4e4372b064f6 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -2009,6 +2009,40 @@ int i2c_get_device_id(const struct i2c_client *client,
}
EXPORT_SYMBOL_GPL(i2c_get_device_id);
+/**
+ * i2c_verify_device_id - verify device ID
+ * @client: The device to query
+ * @id: Expected device ID
+ *
+ * Returns negative errno on error, zero on success.
+ */
+int i2c_verify_device_id(const struct i2c_client *client,
+ const struct i2c_device_identity *id)
+{
+ struct i2c_device_identity real_id;
+ int ret;
+
+ if (id->manufacturer_id == I2C_DEVICE_ID_NONE)
+ return 0;
+
+ ret = i2c_get_device_id(client, &real_id);
+ if (ret < 0)
+ return ret;
+
+ if (id->manufacturer_id != real_id.manufacturer_id ||
+ id->part_id != real_id.part_id ||
+ (id->die_revision != I2C_DEVICE_DIE_REVISION_ANY &&
+ id->die_revision != real_id.die_revision)) {
+ dev_err(&client->dev, "unexpected device id %03x-%03x-%x\n",
+ real_id.manufacturer_id, real_id.part_id,
+ real_id.die_revision);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_verify_device_id);
+
/* ----------------------------------------------------
* the i2c address scanning function
* Will not work for 10-bit addresses!
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 44ad14e016b5..45bae9717ecb 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -189,6 +189,8 @@ i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
u8 command, u8 length, u8 *values);
int i2c_get_device_id(const struct i2c_client *client,
struct i2c_device_identity *id);
+int i2c_verify_device_id(const struct i2c_client *client,
+ const struct i2c_device_identity *id);
#endif /* I2C */
/**
@@ -216,6 +218,7 @@ struct i2c_device_identity {
#define I2C_DEVICE_ID_NONE 0xffff
u16 part_id;
u8 die_revision;
+#define I2C_DEVICE_DIE_REVISION_ANY 0xff
};
enum i2c_alert_protocol {
--
2.7.4
