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Subject[RFC PATCH 1/2] i2c: add i2c_get_device_id() to get the standard i2c device id
Date
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>.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
drivers/i2c/i2c-core-base.c | 33 +++++++++++++++++++++++++++++++++
include/linux/i2c.h | 30 ++++++++++++++++++++++++++++++
2 files changed, 63 insertions(+)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 5a00bf443d06..f496b917529d 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, client->flags,
+ 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!
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 419a38e7c315..44ad14e016b5 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -47,6 +47,7 @@ struct i2c_algorithm;
struct i2c_adapter;
struct i2c_client;
struct i2c_driver;
+struct i2c_device_identity;
union i2c_smbus_data;
struct i2c_board_info;
enum i2c_slave_event;
@@ -186,8 +187,37 @@ extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
extern s32
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);
#endif /* I2C */

+/**
+ * struct i2c_device_identity - i2c client device identification
+ * @manufacturer_id: 0 - 4095, database maintained by NXP
+ * @part_id: 0 - 511, according to manufacturer
+ * @die_revision: 0 - 7, according to manufacturer
+ */
+struct i2c_device_identity {
+ u16 manufacturer_id;
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS 0
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1 1
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2 2
+#define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3 3
+#define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL 4
+#define I2C_DEVICE_ID_ANALOG_DEVICES 5
+#define I2C_DEVICE_ID_STMICROELECTRONICS 6
+#define I2C_DEVICE_ID_ON_SEMICONDUCTOR 7
+#define I2C_DEVICE_ID_SPRINTEK_CORPORATION 8
+#define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG 9
+#define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR 10
+#define I2C_DEVICE_ID_FLIR 11
+#define I2C_DEVICE_ID_O2MICRO 12
+#define I2C_DEVICE_ID_ATMEL 13
+#define I2C_DEVICE_ID_NONE 0xffff
+ u16 part_id;
+ u8 die_revision;
+};
+
enum i2c_alert_protocol {
I2C_PROTOCOL_SMBUS_ALERT,
I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
--
2.11.0
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