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authorPeter Rosin <peda@axentia.se>2018-01-22 08:32:01 +0100
committerPeter Rosin <peda@axentia.se>2018-03-06 10:57:59 +0100
commitdde67eb1beebcd8493e7b30e74a80f0865ab7e36 (patch)
tree341372a636b8cce4fe8672c6529f1401c75255c6 /drivers/i2c
parent4a3928c6f8a53fa1aed28ccba227742486e8ddcb (diff)
i2c: add i2c_get_device_id() to get the standard i2c device id
Can be used during probe to double check that the probed device is what is expected. Loosely based on code from Adrian Fiergolski <adrian.fiergolski@cern.ch>. Tested-by: Adrian Fiergolski <adrian.fiergolski@cern.ch> Reviewed-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Peter Rosin <peda@axentia.se>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/i2c-core-base.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 5a00bf443d06..aa03eeb43814 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -58,6 +58,8 @@
#define I2C_ADDR_7BITS_MAX 0x77
#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
+#define I2C_ADDR_DEVICE_ID 0x7c
+
/*
* core_lock protects i2c_adapter_idr, and guarantees that device detection,
* deletion of detected devices, and attach_adapter calls are serialized
@@ -1968,6 +1970,37 @@ int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
}
EXPORT_SYMBOL(i2c_transfer_buffer_flags);
+/**
+ * i2c_get_device_id - get manufacturer, part id and die revision of a device
+ * @client: The device to query
+ * @id: The queried information
+ *
+ * Returns negative errno on error, zero on success.
+ */
+int i2c_get_device_id(const struct i2c_client *client,
+ struct i2c_device_identity *id)
+{
+ struct i2c_adapter *adap = client->adapter;
+ union i2c_smbus_data raw_id;
+ int ret;
+
+ if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+ return -EOPNOTSUPP;
+
+ raw_id.block[0] = 3;
+ ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
+ I2C_SMBUS_READ, client->addr << 1,
+ I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
+ if (ret)
+ return ret;
+
+ id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
+ id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
+ id->die_revision = raw_id.block[3] & 0x7;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_get_device_id);
+
/* ----------------------------------------------------
* the i2c address scanning function
* Will not work for 10-bit addresses!