Re: [PATCHv4] hwmon: Add tc654 driver

[Guenter Roeck]

On Tue, Oct 11, 2016 at 10:26:31AM +1300, Chris Packham wrote:
> Add support for the tc654 and tc655 fan controllers from Microchip.
> 
> http://ww1.microchip.com/downloads/en/DeviceDoc/20001734C.pdf
> 
> Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>

Applied to -next (after fixing continuation line alignments).

Guenter

> ---
> Changes in v4:
> - tab-align values in #defines
> - ensure locking in set_pwm covers updating cached values
> - populate the cached value for the config register in tc654_probe()
> 
> Changes in v3:
> - typofix in documentation
> - add missing value to tc654_pwm_map, re-generate based on datasheet.
> - remove unnecessary hwmon_dev member from struct tc654_data
> - bug fixes in set_fan_min() and show_pwm_mode()
> - miscellaneous style fixes
>  
> Changes in v2:
> - Add Documentation/hwmon/tc654
> - Incorporate most of the review comments from Guenter. Additional error
>   handling is added. Unused/unnecessary code is removed. I decided not
>   to go down the regmap path yet. I may circle back to it when I look at
>   using regmap in the adm9240 driver.
> 
>  .../devicetree/bindings/i2c/trivial-devices.txt    |   2 +
>  Documentation/hwmon/tc654                          |  31 ++
>  drivers/hwmon/Kconfig                              |  11 +
>  drivers/hwmon/Makefile                             |   1 +
>  drivers/hwmon/tc654.c                              | 514 +++++++++++++++++++++
>  5 files changed, 559 insertions(+)
>  create mode 100644 Documentation/hwmon/tc654
>  create mode 100644 drivers/hwmon/tc654.c
> 
> diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> index 1416c6a0d2cd..833fb9f133d3 100644
> --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> @@ -122,6 +122,8 @@ microchip,mcp4662-502	Microchip 8-bit Dual I2C Digital Potentiometer with NV Mem
>  microchip,mcp4662-103	Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (10k)
>  microchip,mcp4662-503	Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (50k)
>  microchip,mcp4662-104	Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (100k)
> +microchip,tc654		PWM Fan Speed Controller With Fan Fault Detection
> +microchip,tc655		PWM Fan Speed Controller With Fan Fault Detection
>  national,lm63		Temperature sensor with integrated fan control
>  national,lm75		I2C TEMP SENSOR
>  national,lm80		Serial Interface ACPI-Compatible Microprocessor System Hardware Monitor
> diff --git a/Documentation/hwmon/tc654 b/Documentation/hwmon/tc654
> new file mode 100644
> index 000000000000..91a2843f5f98
> --- /dev/null
> +++ b/Documentation/hwmon/tc654
> @@ -0,0 +1,31 @@
> +Kernel driver tc654
> +===================
> +
> +Supported chips:
> +  * Microship TC654 and TC655
> +    Prefix: 'tc654'
> +    Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/20001734C.pdf
> +
> +Authors:
> +        Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
> +        Masahiko Iwamoto <iwamoto@xxxxxxxxxxxxxxxxxxxx>
> +
> +Description
> +-----------
> +This driver implements support for the Microchip TC654 and TC655.
> +
> +The TC654 uses the 2-wire interface compatible with the SMBUS 2.0
> +specification. The TC654 has two (2) inputs for measuring fan RPM and
> +one (1) PWM output which can be used for fan control.
> +
> +Configuration Notes
> +-------------------
> +Ordinarily the pwm1_mode ABI is used for controlling the pwm output
> +mode.  However, for this chip the output is always pwm, and the
> +pwm1_mode determines if the pwm output is controlled via the pwm1 value
> +or via the Vin analog input.
> +
> +
> +Setting pwm1_mode to 1 will cause the pwm output to be driven based on
> +the pwm1 value. Setting pwm1_mode to 0 will cause the pwm output to be
> +driven based on the Vin input.
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 45cef3d2c75c..8681bc65cde5 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -907,6 +907,17 @@ config SENSORS_MCP3021
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called mcp3021.
>  
> +config SENSORS_TC654
> +	tristate "Microchip TC654/TC655 and compatibles"
> +	depends on I2C
> +	help
> +	  If you say yes here you get support for TC654 and TC655.
> +	  The TC654 and TC655 are PWM mode fan speed controllers with
> +	  FanSense technology for use with brushless DC fans.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called tc654.
> +
>  config SENSORS_MENF21BMC_HWMON
>  	tristate "MEN 14F021P00 BMC Hardware Monitoring"
>  	depends on MFD_MENF21BMC
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index aecf4ba17460..c651f0f1d047 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -122,6 +122,7 @@ obj-$(CONFIG_SENSORS_MAX6697)	+= max6697.o
>  obj-$(CONFIG_SENSORS_MAX31790)	+= max31790.o
>  obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
>  obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
> +obj-$(CONFIG_SENSORS_TC654)	+= tc654.o
>  obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
>  obj-$(CONFIG_SENSORS_NCT6683)	+= nct6683.o
>  obj-$(CONFIG_SENSORS_NCT6775)	+= nct6775.o
> diff --git a/drivers/hwmon/tc654.c b/drivers/hwmon/tc654.c
> new file mode 100644
> index 000000000000..04485f6d6983
> --- /dev/null
> +++ b/drivers/hwmon/tc654.c
> @@ -0,0 +1,514 @@
> +/*
> + * tc654.c - Linux kernel modules for fan speed controller
> + *
> + * Copyright (C) 2016 Allied Telesis Labs NZ
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/jiffies.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include <linux/util_macros.h>
> +
> +enum tc654_regs {
> +	TC654_REG_RPM1 = 0x00,	/* RPM Output 1 */
> +	TC654_REG_RPM2 = 0x01,	/* RPM Output 2 */
> +	TC654_REG_FAN_FAULT1 = 0x02,	/* Fan Fault 1 Threshold */
> +	TC654_REG_FAN_FAULT2 = 0x03,	/* Fan Fault 2 Threshold */
> +	TC654_REG_CONFIG = 0x04,	/* Configuration */
> +	TC654_REG_STATUS = 0x05,	/* Status */
> +	TC654_REG_DUTY_CYCLE = 0x06,	/* Fan Speed Duty Cycle */
> +	TC654_REG_MFR_ID = 0x07,	/* Manufacturer Identification */
> +	TC654_REG_VER_ID = 0x08,	/* Version Identification */
> +};
> +
> +/* Macros to easily index the registers */
> +#define TC654_REG_RPM(idx)		(TC654_REG_RPM1 + (idx))
> +#define TC654_REG_FAN_FAULT(idx)	(TC654_REG_FAN_FAULT1 + (idx))
> +
> +/* Config register bits */
> +#define TC654_REG_CONFIG_RES		BIT(6)	/* Resolution Selection */
> +#define TC654_REG_CONFIG_DUTYC		BIT(5)	/* Duty Cycle Control */
> +#define TC654_REG_CONFIG_SDM		BIT(0)	/* Shutdown Mode */
> +
> +/* Status register bits */
> +#define TC654_REG_STATUS_F2F		BIT(1)	/* Fan 2 Fault */
> +#define TC654_REG_STATUS_F1F		BIT(0)	/* Fan 1 Fault */
> +
> +/* RPM resolution for RPM Output registers */
> +#define TC654_HIGH_RPM_RESOLUTION	25	/* 25 RPM resolution */
> +#define TC654_LOW_RPM_RESOLUTION	50	/* 50 RPM resolution */
> +
> +/* Convert to the fan fault RPM threshold from register value */
> +#define TC654_FAN_FAULT_FROM_REG(val)	((val) * 50)	/* 50 RPM resolution */
> +
> +/* Convert to register value from the fan fault RPM threshold */
> +#define TC654_FAN_FAULT_TO_REG(val)	(((val) / 50) & 0xff)
> +
> +/* Register data is read (and cached) at most once per second. */
> +#define TC654_UPDATE_INTERVAL		HZ
> +
> +struct tc654_data {
> +	struct i2c_client *client;
> +
> +	/* update mutex */
> +	struct mutex update_lock;
> +
> +	/* tc654 register cache */
> +	bool valid;
> +	unsigned long last_updated;	/* in jiffies */
> +
> +	u8 rpm_output[2];	/* The fan RPM data for fans 1 and 2 is then
> +				 * written to registers RPM1 and RPM2
> +				 */
> +	u8 fan_fault[2];	/* The Fan Fault Threshold Registers are used to
> +				 * set the fan fault threshold levels for fan 1
> +				 * and fan 2
> +				 */
> +	u8 config;	/* The Configuration Register is an 8-bit read/
> +			 * writable multi-function control register
> +			 *   7: Fan Fault Clear
> +			 *      1 = Clear Fan Fault
> +			 *      0 = Normal Operation (default)
> +			 *   6: Resolution Selection for RPM Output Registers
> +			 *      RPM Output Registers (RPM1 and RPM2) will be
> +			 *      set for
> +			 *      1 = 25 RPM (9-bit) resolution
> +			 *      0 = 50 RPM (8-bit) resolution (default)
> +			 *   5: Duty Cycle Control Method
> +			 *      The V OUT duty cycle will be controlled via
> +			 *      1 = the SMBus interface.
> +			 *      0 = via the V IN analog input pin. (default)
> +			 * 4,3: Fan 2 Pulses Per Rotation
> +			 *      00 = 1
> +			 *      01 = 2 (default)
> +			 *      10 = 4
> +			 *      11 = 8
> +			 * 2,1: Fan 1 Pulses Per Rotation
> +			 *      00 = 1
> +			 *      01 = 2 (default)
> +			 *      10 = 4
> +			 *      11 = 8
> +			 *   0: Shutdown Mode
> +			 *      1 = Shutdown mode.
> +			 *      0 = Normal operation. (default)
> +			 */
> +	u8 status;	/* The Status register provides all the information
> +			 * about what is going on within the TC654/TC655
> +			 * devices.
> +			 * 7,6: Unimplemented, Read as '0'
> +			 *   5: Over-Temperature Fault Condition
> +			 *      1 = Over-Temperature condition has occurred
> +			 *      0 = Normal operation. V IN is less than 2.6V
> +			 *   4: RPM2 Counter Overflow
> +			 *      1 = Fault condition
> +			 *      0 = Normal operation
> +			 *   3: RPM1 Counter Overflow
> +			 *      1 = Fault condition
> +			 *      0 = Normal operation
> +			 *   2: V IN Input Status
> +			 *      1 = V IN is open
> +			 *      0 = Normal operation. voltage present at V IN
> +			 *   1: Fan 2 Fault
> +			 *      1 = Fault condition
> +			 *      0 = Normal operation
> +			 *   0: Fan 1 Fault
> +			 *      1 = Fault condition
> +			 *      0 = Normal operation
> +			 */
> +	u8 duty_cycle;	/* The DUTY_CYCLE register is a 4-bit read/
> +			 * writable register used to control the duty
> +			 * cycle of the V OUT output.
> +			 */
> +};
> +
> +/* helper to grab and cache data, at most one time per second */
> +static struct tc654_data *tc654_update_client(struct device *dev)
> +{
> +	struct tc654_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	int ret = 0;
> +
> +	mutex_lock(&data->update_lock);
> +	if (time_before(jiffies, data->last_updated + TC654_UPDATE_INTERVAL) &&
> +	    likely(data->valid))
> +		goto out;
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(0));
> +	if (ret < 0)
> +		goto out;
> +	data->rpm_output[0] = ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(1));
> +	if (ret < 0)
> +		goto out;
> +	data->rpm_output[1] = ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(0));
> +	if (ret < 0)
> +		goto out;
> +	data->fan_fault[0] = ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(1));
> +	if (ret < 0)
> +		goto out;
> +	data->fan_fault[1] = ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
> +	if (ret < 0)
> +		goto out;
> +	data->config = ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_STATUS);
> +	if (ret < 0)
> +		goto out;
> +	data->status = ret;
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_DUTY_CYCLE);
> +	if (ret < 0)
> +		goto out;
> +	data->duty_cycle = ret & 0x0f;
> +
> +	data->last_updated = jiffies;
> +	data->valid = true;
> +out:
> +	mutex_unlock(&data->update_lock);
> +
> +	if (ret < 0)		/* upon error, encode it in return value */
> +		data = ERR_PTR(ret);
> +
> +	return data;
> +}
> +
> +/*
> + * sysfs attributes
> + */
> +
> +static ssize_t show_fan(struct device *dev, struct device_attribute *da,
> +			char *buf)
> +{
> +	int nr = to_sensor_dev_attr(da)->index;
> +	struct tc654_data *data = tc654_update_client(dev);
> +	int val;
> +
> +	if (IS_ERR(data))
> +		return PTR_ERR(data);
> +
> +	if (data->config & TC654_REG_CONFIG_RES)
> +		val = data->rpm_output[nr] * TC654_HIGH_RPM_RESOLUTION;
> +	else
> +		val = data->rpm_output[nr] * TC654_LOW_RPM_RESOLUTION;
> +
> +	return sprintf(buf, "%d\n", val);
> +}
> +
> +static ssize_t show_fan_min(struct device *dev, struct device_attribute *da,
> +			    char *buf)
> +{
> +	int nr = to_sensor_dev_attr(da)->index;
> +	struct tc654_data *data = tc654_update_client(dev);
> +
> +	if (IS_ERR(data))
> +		return PTR_ERR(data);
> +
> +	return sprintf(buf, "%d\n",
> +		       TC654_FAN_FAULT_FROM_REG(data->fan_fault[nr]));
> +}
> +
> +static ssize_t set_fan_min(struct device *dev, struct device_attribute *da,
> +			   const char *buf, size_t count)
> +{
> +	int nr = to_sensor_dev_attr(da)->index;
> +	struct tc654_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	unsigned long val;
> +	int ret;
> +
> +	if (kstrtoul(buf, 10, &val))
> +		return -EINVAL;
> +
> +	val = clamp_val(val, 0, 12750);
> +
> +	mutex_lock(&data->update_lock);
> +
> +	data->fan_fault[nr] = TC654_FAN_FAULT_TO_REG(val);
> +	ret = i2c_smbus_write_byte_data(client, TC654_REG_FAN_FAULT(nr),
> +					data->fan_fault[nr]);
> +
> +	mutex_unlock(&data->update_lock);
> +	return ret < 0 ? ret : count;
> +}
> +
> +static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da,
> +			      char *buf)
> +{
> +	int nr = to_sensor_dev_attr(da)->index;
> +	struct tc654_data *data = tc654_update_client(dev);
> +	int val;
> +
> +	if (IS_ERR(data))
> +		return PTR_ERR(data);
> +
> +	if (nr == 0)
> +		val = !!(data->status & TC654_REG_STATUS_F1F);
> +	else
> +		val = !!(data->status & TC654_REG_STATUS_F2F);
> +
> +	return sprintf(buf, "%d\n", val);
> +}
> +
> +static const u8 TC654_FAN_PULSE_SHIFT[] = { 1, 3 };
> +
> +static ssize_t show_fan_pulses(struct device *dev, struct device_attribute *da,
> +			      char *buf)
> +{
> +	int nr = to_sensor_dev_attr(da)->index;
> +	struct tc654_data *data = tc654_update_client(dev);
> +	u8 val;
> +
> +	if (IS_ERR(data))
> +		return PTR_ERR(data);
> +
> +	val = BIT((data->config >> TC654_FAN_PULSE_SHIFT[nr]) & 0x03);
> +	return sprintf(buf, "%d\n", val);
> +}
> +
> +static ssize_t set_fan_pulses(struct device *dev, struct device_attribute *da,
> +			     const char *buf, size_t count)
> +{
> +	int nr = to_sensor_dev_attr(da)->index;
> +	struct tc654_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	u8 config;
> +	unsigned long val;
> +	int ret;
> +
> +	if (kstrtoul(buf, 10, &val))
> +		return -EINVAL;
> +
> +	switch (val) {
> +	case 1:
> +		config = 0;
> +		break;
> +	case 2:
> +		config = 1;
> +		break;
> +	case 4:
> +		config = 2;
> +		break;
> +	case 8:
> +		config = 3;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	mutex_lock(&data->update_lock);
> +
> +	data->config &= ~(0x03 << TC654_FAN_PULSE_SHIFT[nr]);
> +	data->config |= (config << TC654_FAN_PULSE_SHIFT[nr]);
> +	ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
> +
> +	mutex_unlock(&data->update_lock);
> +	return ret < 0 ? ret : count;
> +}
> +
> +static ssize_t show_pwm_mode(struct device *dev,
> +			     struct device_attribute *da, char *buf)
> +{
> +	struct tc654_data *data = tc654_update_client(dev);
> +
> +	if (IS_ERR(data))
> +		return PTR_ERR(data);
> +
> +	return sprintf(buf, "%d\n", !!(data->config & TC654_REG_CONFIG_DUTYC));
> +}
> +
> +static ssize_t set_pwm_mode(struct device *dev,
> +			    struct device_attribute *da,
> +			    const char *buf, size_t count)
> +{
> +	struct tc654_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	unsigned long val;
> +	int ret;
> +
> +	if (kstrtoul(buf, 10, &val))
> +		return -EINVAL;
> +
> +	if (val != 0 && val != 1)
> +		return -EINVAL;
> +
> +	mutex_lock(&data->update_lock);
> +
> +	if (val)
> +		data->config |= TC654_REG_CONFIG_DUTYC;
> +	else
> +		data->config &= ~TC654_REG_CONFIG_DUTYC;
> +
> +	ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
> +
> +	mutex_unlock(&data->update_lock);
> +	return ret < 0 ? ret : count;
> +}
> +
> +static const int tc654_pwm_map[16] = { 77,  88, 102, 112, 124, 136, 148, 160,
> +				      172, 184, 196, 207, 219, 231, 243, 255};
> +
> +static ssize_t show_pwm(struct device *dev, struct device_attribute *da,
> +			       char *buf)
> +{
> +	struct tc654_data *data = tc654_update_client(dev);
> +	int pwm;
> +
> +	if (IS_ERR(data))
> +		return PTR_ERR(data);
> +
> +	if (data->config & TC654_REG_CONFIG_SDM)
> +		pwm = 0;
> +	else
> +		pwm = tc654_pwm_map[data->duty_cycle];
> +
> +	return sprintf(buf, "%d\n", pwm);
> +}
> +
> +static ssize_t set_pwm(struct device *dev, struct device_attribute *da,
> +			      const char *buf, size_t count)
> +{
> +	struct tc654_data *data = dev_get_drvdata(dev);
> +	struct i2c_client *client = data->client;
> +	unsigned long val;
> +	int ret;
> +
> +	if (kstrtoul(buf, 10, &val))
> +		return -EINVAL;
> +	if (val > 255)
> +		return -EINVAL;
> +
> +	mutex_lock(&data->update_lock);
> +
> +	if (val == 0)
> +		data->config |= TC654_REG_CONFIG_SDM;
> +	else
> +		data->config &= ~TC654_REG_CONFIG_SDM;
> +
> +	data->duty_cycle = find_closest(val, tc654_pwm_map,
> +					ARRAY_SIZE(tc654_pwm_map));
> +
> +	ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = i2c_smbus_write_byte_data(client, TC654_REG_DUTY_CYCLE,
> +				  data->duty_cycle);
> +
> +out:
> +	mutex_unlock(&data->update_lock);
> +	return ret < 0 ? ret : count;
> +}
> +
> +static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL, 0);
> +static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, show_fan, NULL, 1);
> +static SENSOR_DEVICE_ATTR(fan1_min, S_IWUSR | S_IRUGO, show_fan_min,
> +			  set_fan_min, 0);
> +static SENSOR_DEVICE_ATTR(fan2_min, S_IWUSR | S_IRUGO, show_fan_min,
> +			  set_fan_min, 1);
> +static SENSOR_DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL, 0);
> +static SENSOR_DEVICE_ATTR(fan2_alarm, S_IRUGO, show_fan_alarm, NULL, 1);
> +static SENSOR_DEVICE_ATTR(fan1_pulses, S_IWUSR | S_IRUGO, show_fan_pulses,
> +			  set_fan_pulses, 0);
> +static SENSOR_DEVICE_ATTR(fan2_pulses, S_IWUSR | S_IRUGO, show_fan_pulses,
> +			  set_fan_pulses, 1);
> +static SENSOR_DEVICE_ATTR(pwm1_mode, S_IWUSR | S_IRUGO,
> +			  show_pwm_mode, set_pwm_mode, 0);
> +static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, show_pwm,
> +			  set_pwm, 0);
> +
> +/* Driver data */
> +static struct attribute *tc654_attrs[] = {
> +	&sensor_dev_attr_fan1_input.dev_attr.attr,
> +	&sensor_dev_attr_fan2_input.dev_attr.attr,
> +	&sensor_dev_attr_fan1_min.dev_attr.attr,
> +	&sensor_dev_attr_fan2_min.dev_attr.attr,
> +	&sensor_dev_attr_fan1_alarm.dev_attr.attr,
> +	&sensor_dev_attr_fan2_alarm.dev_attr.attr,
> +	&sensor_dev_attr_fan1_pulses.dev_attr.attr,
> +	&sensor_dev_attr_fan2_pulses.dev_attr.attr,
> +	&sensor_dev_attr_pwm1_mode.dev_attr.attr,
> +	&sensor_dev_attr_pwm1.dev_attr.attr,
> +	NULL
> +};
> +
> +ATTRIBUTE_GROUPS(tc654);
> +
> +/*
> + * device probe and removal
> + */
> +
> +static int tc654_probe(struct i2c_client *client,
> +		       const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct tc654_data *data;
> +	struct device *hwmon_dev;
> +	int ret;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> +		return -ENODEV;
> +
> +	data = devm_kzalloc(dev, sizeof(struct tc654_data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->client = client;
> +	mutex_init(&data->update_lock);
> +
> +	ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
> +	if (ret < 0)
> +		return ret;
> +
> +	data->config = ret;
> +
> +	hwmon_dev =
> +	    devm_hwmon_device_register_with_groups(dev, client->name, data,
> +						   tc654_groups);
> +	return PTR_ERR_OR_ZERO(hwmon_dev);
> +}
> +
> +static const struct i2c_device_id tc654_id[] = {
> +	{"tc654", 0},
> +	{"tc655", 0},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, tc654_id);
> +
> +static struct i2c_driver tc654_driver = {
> +	.driver = {
> +		   .name = "tc654",
> +		   },
> +	.probe = tc654_probe,
> +	.id_table = tc654_id,
> +};
> +
> +module_i2c_driver(tc654_driver);
> +
> +MODULE_AUTHOR("Allied Telesis Labs");
> +MODULE_DESCRIPTION("Microchip TC654/TC655 driver");
> +MODULE_LICENSE("GPL");