hwmon: (pmbus/max31785) Add dual tachometer support
The dual tachometer feature is implemented in hardware with a TACHSEL input to indicate the rotor under measurement, and exposed on the device by extending the READ_FAN_SPEED_1 word with two extra bytes*. The need to read the non-standard four-byte response leads to a cut-down implementation of i2c_smbus_xfer_emulated() included in the driver. Further, to expose the second rotor tachometer value to userspace the values are exposed through virtual pages. We re-route accesses to FAN_CONFIG_1_2 and READ_FAN_SPEED_1 on pages 23-28 (not defined by the hardware) to the same registers on pages 0-5, and with the latter command we extract the value from the second word of the four-byte response. * The documentation recommends the slower rotor be associated with TACHSEL=0, which corresponds to the first word of the response. The TACHSEL=0 measurement is used by the controller's closed-loop fan management to judge target fan rate. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Andrew Jeffery
Guenter Roeck
parent
464df6fa37
commit
cf583b4275
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@ -17,8 +17,9 @@ management with temperature and remote voltage sensing. Various fan control
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features are provided, including PWM frequency control, temperature hysteresis,
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dual tachometer measurements, and fan health monitoring.
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For dual rotor fan configuration, the MAX31785 exposes the slowest rotor of the
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two in the fan[1-4]_input attributes.
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For dual-rotor configurations the MAX31785A exposes the second rotor tachometer
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readings in attributes fan[5-8]_input. By contrast the MAX31785 only exposes
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the slowest rotor measurement, and does so in the fan[1-4]_input attributes.
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Usage Notes
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-----------
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@ -31,7 +32,8 @@ Sysfs attributes
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fan[1-4]_alarm Fan alarm.
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fan[1-4]_fault Fan fault.
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fan[1-4]_input Fan RPM.
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fan[1-8]_input Fan RPM. On the MAX31785A, inputs 5-8 correspond to the
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second rotor of fans 1-4
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fan[1-4]_target Fan input target
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in[1-6]_crit Critical maximum output voltage
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@ -16,9 +16,79 @@
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enum max31785_regs {
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MFR_REVISION = 0x9b,
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MFR_FAN_CONFIG = 0xf1,
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};
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#define MAX31785 0x3030
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#define MAX31785A 0x3040
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#define MFR_FAN_CONFIG_DUAL_TACH BIT(12)
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#define MAX31785_NR_PAGES 23
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#define MAX31785_NR_FAN_PAGES 6
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static int max31785_read_byte_data(struct i2c_client *client, int page,
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int reg)
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{
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if (page < MAX31785_NR_PAGES)
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return -ENODATA;
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switch (reg) {
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case PMBUS_VOUT_MODE:
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return -ENOTSUPP;
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case PMBUS_FAN_CONFIG_12:
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return pmbus_read_byte_data(client, page - MAX31785_NR_PAGES,
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reg);
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}
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return -ENODATA;
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}
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static int max31785_write_byte(struct i2c_client *client, int page, u8 value)
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{
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if (page < MAX31785_NR_PAGES)
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return -ENODATA;
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return -ENOTSUPP;
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}
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static int max31785_read_long_data(struct i2c_client *client, int page,
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int reg, u32 *data)
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{
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unsigned char cmdbuf[1];
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unsigned char rspbuf[4];
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int rc;
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struct i2c_msg msg[2] = {
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{
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.addr = client->addr,
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.flags = 0,
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.len = sizeof(cmdbuf),
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.buf = cmdbuf,
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},
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{
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.addr = client->addr,
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.flags = I2C_M_RD,
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.len = sizeof(rspbuf),
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.buf = rspbuf,
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},
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};
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cmdbuf[0] = reg;
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rc = pmbus_set_page(client, page);
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if (rc < 0)
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return rc;
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rc = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
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if (rc < 0)
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return rc;
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*data = (rspbuf[0] << (0 * 8)) | (rspbuf[1] << (1 * 8)) |
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(rspbuf[2] << (2 * 8)) | (rspbuf[3] << (3 * 8));
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return rc;
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}
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static int max31785_get_pwm(struct i2c_client *client, int page)
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{
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@ -62,9 +132,30 @@ static int max31785_get_pwm_mode(struct i2c_client *client, int page)
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static int max31785_read_word_data(struct i2c_client *client, int page,
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int reg)
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{
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u32 val;
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int rv;
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switch (reg) {
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case PMBUS_READ_FAN_SPEED_1:
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if (page < MAX31785_NR_PAGES)
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return -ENODATA;
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rv = max31785_read_long_data(client, page - MAX31785_NR_PAGES,
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reg, &val);
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if (rv < 0)
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return rv;
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rv = (val >> 16) & 0xffff;
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break;
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case PMBUS_FAN_COMMAND_1:
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/*
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* PMBUS_FAN_COMMAND_x is probed to judge whether or not to
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* expose fan control registers.
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*
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* Don't expose fan_target attribute for virtual pages.
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*/
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rv = (page >= MAX31785_NR_PAGES) ? -ENOTSUPP : -ENODATA;
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break;
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case PMBUS_VIRT_PWM_1:
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rv = max31785_get_pwm(client, page);
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break;
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@ -157,11 +248,15 @@ static int max31785_write_word_data(struct i2c_client *client, int page,
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#define MAX31785_VOUT_FUNCS \
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(PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT)
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#define MAX37185_NUM_FAN_PAGES 6
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static const struct pmbus_driver_info max31785_info = {
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.pages = MAX31785_NR_PAGES,
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.write_word_data = max31785_write_word_data,
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.read_byte_data = max31785_read_byte_data,
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.read_word_data = max31785_read_word_data,
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.write_byte = max31785_write_byte,
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/* RPM */
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.format[PSC_FAN] = direct,
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@ -208,13 +303,46 @@ static const struct pmbus_driver_info max31785_info = {
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.func[22] = MAX31785_VOUT_FUNCS,
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};
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static int max31785_configure_dual_tach(struct i2c_client *client,
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struct pmbus_driver_info *info)
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{
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int ret;
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int i;
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for (i = 0; i < MAX31785_NR_FAN_PAGES; i++) {
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ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
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if (ret < 0)
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return ret;
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ret = i2c_smbus_read_word_data(client, MFR_FAN_CONFIG);
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if (ret < 0)
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return ret;
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if (ret & MFR_FAN_CONFIG_DUAL_TACH) {
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int virtual = MAX31785_NR_PAGES + i;
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info->pages = virtual + 1;
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info->func[virtual] |= PMBUS_HAVE_FAN12;
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info->func[virtual] |= PMBUS_PAGE_VIRTUAL;
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}
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}
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return 0;
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}
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static int max31785_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct pmbus_driver_info *info;
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bool dual_tach = false;
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s64 ret;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_BYTE_DATA |
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I2C_FUNC_SMBUS_WORD_DATA))
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return -ENODEV;
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info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL);
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if (!info)
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return -ENOMEM;
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@ -225,6 +353,25 @@ static int max31785_probe(struct i2c_client *client,
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if (ret < 0)
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return ret;
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ret = i2c_smbus_read_word_data(client, MFR_REVISION);
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if (ret < 0)
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return ret;
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if (ret == MAX31785A) {
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dual_tach = true;
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} else if (ret == MAX31785) {
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if (!strcmp("max31785a", id->name))
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dev_warn(dev, "Expected max3175a, found max31785: cannot provide secondary tachometer readings\n");
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} else {
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return -ENODEV;
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}
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if (dual_tach) {
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ret = max31785_configure_dual_tach(client, info);
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if (ret < 0)
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return ret;
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}
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return pmbus_do_probe(client, id, info);
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}
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