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| author |   Peter Rosin <peda@axentia.se> | 2018-01-22 08:32:01 +0100 |
|---|---|---|
| committer | Peter Rosin <peda@axentia.se> | 2018-03-06 10:57:59 +0100 |
| commit | dde67eb1beebcd8493e7b30e74a80f0865ab7e36 (patch) | |
| tree | 341372a636b8cce4fe8672c6529f1401c75255c6 /drivers/i2c | |
| parent | Linux 4.16-rc3 (diff) | |
| download | linux-dev-dde67eb1beebcd8493e7b30e74a80f0865ab7e36.tar.xz linux-dev-dde67eb1beebcd8493e7b30e74a80f0865ab7e36.zip | |
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.c | 33 |
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! |