text: // SPDX-License-Identifier: GPL-2.0-or-later
  
  /* Driver for the Texas Instruments TMP464 SMBus temperature sensor IC.
   * Supported models: TMP464, TMP468
  
   * Copyright (C) 2022 Agathe Porte <agathe.porte@nokia.com>
   * Preliminary support by:
   * Lionel Pouliquen <lionel.lp.pouliquen@nokia.com>
   */
  
  #include <linux/err.h>
  #include <linux/hwmon.h>
  #include <linux/i2c.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/of_device.h>
  #include <linux/regmap.h>
  #include <linux/slab.h>
  
  /* Addresses to scan */
  static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END };
  
  #define TMP464_NUM_CHANNELS		5	/* chan 0 is internal, 1-4 are remote */
  #define TMP468_NUM_CHANNELS		9	/* chan 0 is internal, 1-8 are remote */
  
  #define MAX_CHANNELS			9
  
  #define TMP464_TEMP_REG(channel)	(channel)
  #define TMP464_TEMP_OFFSET_REG(channel)	(0x40 + ((channel) - 1) * 8)
  #define TMP464_N_FACTOR_REG(channel)	(0x41 + ((channel) - 1) * 8)
  
  static const u8 TMP464_THERM_LIMIT[MAX_CHANNELS] = {
  	0x39, 0x42, 0x4A, 0x52, 0x5A, 0x62, 0x6a, 0x72, 0x7a };
  static const u8 TMP464_THERM2_LIMIT[MAX_CHANNELS] = {
  	0x3A, 0x43, 0x4B, 0x53, 0x5B, 0x63, 0x6b, 0x73, 0x7b };
  
  #define TMP464_THERM_STATUS_REG			0x21
  #define TMP464_THERM2_STATUS_REG		0x22
  #define TMP464_REMOTE_OPEN_REG			0x23
  #define TMP464_CONFIG_REG			0x30
  #define TMP464_TEMP_HYST_REG			0x38
  #define TMP464_LOCK_REG				0xc4
  
  /* Identification */
  #define TMP464_MANUFACTURER_ID_REG		0xFE
  #define TMP464_DEVICE_ID_REG			0xFF
  
  /* Flags */
  #define TMP464_CONFIG_SHUTDOWN			BIT(5)
  #define TMP464_CONFIG_RANGE			0x04
  #define TMP464_CONFIG_REG_REN(x)		(BIT(7 + (x)))
  #define TMP464_CONFIG_REG_REN_MASK		GENMASK(15, 7)
  #define TMP464_CONFIG_CONVERSION_RATE_B0	2
  #define TMP464_CONFIG_CONVERSION_RATE_B2	4
  #define TMP464_CONFIG_CONVERSION_RATE_MASK      GENMASK(TMP464_CONFIG_CONVERSION_RATE_B2, \
  							TMP464_CONFIG_CONVERSION_RATE_B0)
  
  #define TMP464_UNLOCK_VAL			0xeb19
  #define TMP464_LOCK_VAL				0x5ca6
  #define TMP464_LOCKED				0x8000
  
  /* Manufacturer / Device ID's */
  #define TMP464_MANUFACTURER_ID			0x5449
  #define TMP464_DEVICE_ID			0x1468
  #define TMP468_DEVICE_ID			0x0468
  
  static const struct i2c_device_id tmp464_id[] = {
  	{ "tmp464", TMP464_NUM_CHANNELS },
  	{ "tmp468", TMP468_NUM_CHANNELS },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, tmp464_id);
  
  static const struct of_device_id __maybe_unused tmp464_of_match[] = {
  	{
  		.compatible = "ti,tmp464",
  		.data = (void *)TMP464_NUM_CHANNELS
  	},
  	{
  		.compatible = "ti,tmp468",
  		.data = (void *)TMP468_NUM_CHANNELS
  	},
  	{},
  };
  MODULE_DEVICE_TABLE(of, tmp464_of_match);
  
  struct tmp464_channel {
  	const char *label;
  	bool enabled;
  };
  
  struct tmp464_data {
  	struct regmap *regmap;
  	struct mutex update_lock;
  	int channels;
  	s16 config_orig;
  	u16 open_reg;
  	unsigned long last_updated;
  	bool valid;
  	int update_interval;
  	struct tmp464_channel channel[MAX_CHANNELS];
  };
  
  static int temp_from_reg(s16 reg)
  {
  	return DIV_ROUND_CLOSEST((reg >> 3) * 625, 10);
  }
  
  static s16 temp_to_limit_reg(long temp)
  {
  	return DIV_ROUND_CLOSEST(temp, 500) << 6;
  }
  
  static s16 temp_to_offset_reg(long temp)
  {
  	return DIV_ROUND_CLOSEST(temp * 10, 625) << 3;
  }
  
  static int tmp464_enable_channels(struct tmp464_data *data)
  {
  	struct regmap *regmap = data->regmap;
  	u16 enable = 0;
  	int i;
  
  	for (i = 0; i < data->channels; i++)
  		if (data->channel[i].enabled)
  			enable |= TMP464_CONFIG_REG_REN(i);
  
  	return regmap_update_bits(regmap, TMP464_CONFIG_REG, TMP464_CONFIG_REG_REN_MASK, enable);
  }
  
  static int tmp464_chip_read(struct device *dev, u32 attr, int channel, long *val)
  {
  	struct tmp464_data *data = dev_get_drvdata(dev);
  
  	switch (attr) {
  	case hwmon_chip_update_interval:
  		*val = data->update_interval;
  		return 0;
  	default:
  		return -EOPNOTSUPP;
  	}
  }
  
  static int tmp464_temp_read(struct device *dev, u32 attr, int channel, long *val)
  {
  	struct tmp464_data *data = dev_get_drvdata(dev);
  	struct regmap *regmap = data->regmap;
  	unsigned int regval, regval2;
  	int err = 0;
  
  	mutex_lock(&data->update_lock);
  
  	switch (attr) {
  	case hwmon_temp_max_alarm:
  		err = regmap_read(regmap, TMP464_THERM_STATUS_REG, &regval);
  		if (err < 0)
  			break;
  		*val = !!(regval & BIT(channel + 7));
  		break;
  	case hwmon_temp_crit_alarm:
  		err = regmap_read(regmap, TMP464_THERM2_STATUS_REG, &regval);
  		if (err < 0)
  			break;
  		*val = !!(regval & BIT(channel + 7));
  		break;
  	case hwmon_temp_fault:
  		/*
  		 * The chip clears TMP464_REMOTE_OPEN_REG after it is read
  		 * and only updates it after the next measurement cycle is
  		 * complete. That means we have to cache the value internally
  		 * for one measurement cycle and report the cached value.
  		 */
  		if (!data->valid || time_after(jiffies, data->last_updated +
  					       msecs_to_jiffies(data->update_interval))) {
  			err = regmap_read(regmap, TMP464_REMOTE_OPEN_REG, &regval);
  			if (err < 0)
  				break;
  			data->open_reg = regval;
  			data->last_updated = jiffies;
  			data->valid = true;
  		}
  		*val = !!(data->open_reg & BIT(channel + 7));
  		break;
  	case hwmon_temp_max_hyst:
  		err = regmap_read(regmap, TMP464_THERM_LIMIT[channel], &regval);
  		if (err < 0)
  			break;
  		err = regmap_read(regmap, TMP464_TEMP_HYST_REG, &regval2);
  		if (err < 0)
  			break;
  		regval -= regval2;
  		*val = temp_from_reg(regval);
  		break;
  	case hwmon_temp_max:
  		err = regmap_read(regmap, TMP464_THERM_LIMIT[channel], &regval);
  		if (err < 0)
  			break;
  		*val = temp_from_reg(regval);
  		break;
  	case hwmon_temp_crit_hyst:
  		err = regmap_read(regmap, TMP464_THERM2_LIMIT[channel], &regval);
  		if (err < 0)
  			break;
  		err = regmap_read(regmap, TMP464_TEMP_HYST_REG, &regval2);
  		if (err < 0)
  			break;
  		regval -= regval2;
  		*val = temp_from_reg(regval);
  		break;
  	case hwmon_temp_crit:
  		err = regmap_read(regmap, TMP464_THERM2_LIMIT[channel], &regval);
  		if (err < 0)
  			break;
  		*val = temp_from_reg(regval);
  		break;
  	case hwmon_temp_offset:
  		err = regmap_read(regmap, TMP464_TEMP_OFFSET_REG(channel), &regval);
  		if (err < 0)
  			break;
  		*val = temp_from_reg(regval);
  		break;
  	case hwmon_temp_input:
  		if (!data->channel[channel].enabled) {
  			err = -ENODATA;
  			break;
  		}
  		err = regmap_read(regmap, TMP464_TEMP_REG(channel), &regval);
  		if (err < 0)
  			break;
  		*val = temp_from_reg(regval);
  		break;
  	case hwmon_temp_enable:
  		*val = data->channel[channel].enabled;
  		break;
  	default:
  		err = -EOPNOTSUPP;
  		break;
  	}
  
  	mutex_unlock(&data->update_lock);
  
  	return err;
  }
  
  static int tmp464_read(struct device *dev, enum hwmon_sensor_types type,
  		       u32 attr, int channel, long *val)
  {
  	switch (type) {
  	case hwmon_chip:
  		return tmp464_chip_read(dev, attr, channel, val);
  	case hwmon_temp:
  		return tmp464_temp_read(dev, attr, channel, val);
  	default:
  		return -EOPNOTSUPP;
  	}
  }
  
  static int tmp464_read_string(struct device *dev, enum hwmon_sensor_types type,
  			      u32 attr, int channel, const char **str)
  {
  	struct tmp464_data *data = dev_get_drvdata(dev);
  
  	*str = data->channel[channel].label;
  
  	return 0;
  }
  
  static int tmp464_set_convrate(struct tmp464_data *data, long interval)
  {
  	int rate;
  
  	/*
  	 * For valid rates, interval in milli-seconds can be calculated as
  	 *      interval = 125 << (7 - rate);
  	 * or
  	 *      interval = (1 << (7 - rate)) * 125;
  	 * The rate is therefore
  	 *      rate = 7 - __fls(interval / 125);
  	 * and the rounded rate is
  	 *      rate = 7 - __fls(interval * 4 / (125 * 3));
  	 * Use clamp_val() to avoid overflows, and to ensure valid input
  	 * for __fls.
  	 */
  	interval = clamp_val(interval, 125, 16000);
  	rate = 7 - __fls(interval * 4 / (125 * 3));
  	data->update_interval = 125 << (7 - rate);
  
  	return regmap_update_bits(data->regmap, TMP464_CONFIG_REG,
  				  TMP464_CONFIG_CONVERSION_RATE_MASK,
  				  rate << TMP464_CONFIG_CONVERSION_RATE_B0);
  }
  
  static int tmp464_chip_write(struct tmp464_data *data, u32 attr, int channel, long val)
  {
  	switch (attr) {
  	case hwmon_chip_update_interval:
  		return tmp464_set_convrate(data, val);
  	default:
  		return -EOPNOTSUPP;
  	}
  }
  
  static int tmp464_temp_write(struct tmp464_data *data, u32 attr, int channel, long val)
  {
  	struct regmap *regmap = data->regmap;
  	unsigned int regval;
  	int err = 0;
  
  	switch (attr) {
  	case hwmon_temp_max_hyst:
  		err = regmap_read(regmap, TMP464_THERM_LIMIT[0], &regval);
  		if (err < 0)
  			break;
  		val = clamp_val(val, -256000, 256000);	/* prevent overflow/underflow */
  		val = clamp_val(temp_from_reg(regval) - val, 0, 255000);
  		err = regmap_write(regmap, TMP464_TEMP_HYST_REG,
  				   DIV_ROUND_CLOSEST(val, 1000) << 7);
  		break;
  	case hwmon_temp_max:
  		val = temp_to_limit_reg(clamp_val(val, -255000, 255500));
  		err = regmap_write(regmap, TMP464_THERM_LIMIT[channel], val);
  		break;
  	case hwmon_temp_crit:
  		val = temp_to_limit_reg(clamp_val(val, -255000, 255500));
  		err = regmap_write(regmap, TMP464_THERM2_LIMIT[channel], val);
  		break;
  	case hwmon_temp_offset:
  		val = temp_to_offset_reg(clamp_val(val, -128000, 127937));
  		err = regmap_write(regmap, TMP464_TEMP_OFFSET_REG(channel), val);
  		break;
  	case hwmon_temp_enable:
  		data->channel[channel].enabled = !!val;
  		err = tmp464_enable_channels(data);
  		break;
  	default:
  		err = -EOPNOTSUPP;
  		break;
  	}
  
  	return err;
  }
  
  static int tmp464_write(struct device *dev, enum hwmon_sensor_types type,
  			u32 attr, int channel, long val)
  {
  	struct tmp464_data *data = dev_get_drvdata(dev);
  	int err;
  
  	mutex_lock(&data->update_lock);
  
  	switch (type) {
  	case hwmon_chip:
  		err = tmp464_chip_write(data, attr, channel, val);
  		break;
  	case hwmon_temp:
  		err = tmp464_temp_write(data, attr, channel, val);
  		break;
  	default:
  		err = -EOPNOTSUPP;
  		break;
  	}
  
  	mutex_unlock(&data->update_lock);
  
  	return err;
  }
  
  static umode_t tmp464_is_visible(const void *_data, enum hwmon_sensor_types type,
  				 u32 attr, int channel)
  {
  	const struct tmp464_data *data = _data;
  
  	if (channel >= data->channels)
  		return 0;
  
  	if (type == hwmon_chip) {
  		if (attr == hwmon_chip_update_interval)
  			return 0644;
  		return 0;
  	}
  
  	switch (attr) {
  	case hwmon_temp_input:
  	case hwmon_temp_max_alarm:
  	case hwmon_temp_crit_alarm:
  	case hwmon_temp_crit_hyst:
  		return 0444;
  	case hwmon_temp_enable:
  	case hwmon_temp_max:
  	case hwmon_temp_crit:
  		return 0644;
  	case hwmon_temp_max_hyst:
  		if (!channel)
  			return 0644;
  		return 0444;
  	case hwmon_temp_label:
  		if (data->channel[channel].label)
  			return 0444;
  		return 0;
  	case hwmon_temp_fault:
  		if (channel)
  			return 0444;
  		return 0;
  	case hwmon_temp_offset:
  		if (channel)
  			return 0644;
  		return 0;
  	default:
  		return 0;
  	}
  }
  
  static void tmp464_restore_lock(void *regmap)
  {
  	regmap_write(regmap, TMP464_LOCK_REG, TMP464_LOCK_VAL);
  }
  
  static void tmp464_restore_config(void *_data)
  {
  	struct tmp464_data *data = _data;
  
  	regmap_write(data->regmap, TMP464_CONFIG_REG, data->config_orig);
  }
  
  static int tmp464_init_client(struct device *dev, struct tmp464_data *data)
  {
  	struct regmap *regmap = data->regmap;
  	unsigned int regval;
  	int err;
  
  	err = regmap_read(regmap, TMP464_LOCK_REG, &regval);
  	if (err)
  		return err;
  	if (regval == TMP464_LOCKED) {
  		/* Explicitly unlock chip if it is locked */
  		err = regmap_write(regmap, TMP464_LOCK_REG, TMP464_UNLOCK_VAL);
  		if (err)
  			return err;
  		/* and lock it again when unloading the driver */
  		err = devm_add_action_or_reset(dev, tmp464_restore_lock, regmap);
  		if (err)
  			return err;
  	}
  
  	err = regmap_read(regmap, TMP464_CONFIG_REG, &regval);
  	if (err)
  		return err;
  	data->config_orig = regval;
  	err = devm_add_action_or_reset(dev, tmp464_restore_config, data);
  	if (err)
  		return err;
  
  	/* Default to 500 ms update interval */
  	err = regmap_update_bits(regmap, TMP464_CONFIG_REG,
  				 TMP464_CONFIG_CONVERSION_RATE_MASK | TMP464_CONFIG_SHUTDOWN,
  				 BIT(TMP464_CONFIG_CONVERSION_RATE_B0) |
  				 BIT(TMP464_CONFIG_CONVERSION_RATE_B2));
  	if (err)
  		return err;
  
  	data->update_interval = 500;
  
  	return tmp464_enable_channels(data);
  }
  
  static int tmp464_detect(struct i2c_client *client,
  			 struct i2c_board_info *info)
  {
  	struct i2c_adapter *adapter = client->adapter;
  	char *name, *chip;
  	int reg;
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
  		return -ENODEV;
  
  	reg = i2c_smbus_read_word_swapped(client, TMP464_MANUFACTURER_ID_REG);
  	if (reg < 0)
  		return reg;
  	if (reg != TMP464_MANUFACTURER_ID)
  		return -ENODEV;
  
  	/* Check for "always return zero" bits */
  	reg = i2c_smbus_read_word_swapped(client, TMP464_THERM_STATUS_REG);
  	if (reg < 0)
  		return reg;
  	if (reg & 0x1f)
  		return -ENODEV;
  	reg = i2c_smbus_read_word_swapped(client, TMP464_THERM2_STATUS_REG);
  	if (reg < 0)
  		return reg;
  	if (reg & 0x1f)
  		return -ENODEV;
  
  	reg = i2c_smbus_read_word_swapped(client, TMP464_DEVICE_ID_REG);
  	if (reg < 0)
  		return reg;
  	switch (reg) {
  	case TMP464_DEVICE_ID:
  		name = "tmp464";
  		chip = "TMP464";
  		break;
  	case TMP468_DEVICE_ID:
  		name = "tmp468";
  		chip = "TMP468";
  		break;
  	default:
  		return -ENODEV;
  	}
  
  	strscpy(info->type, name, I2C_NAME_SIZE);
  	dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n", chip, client->addr);
  
  	return 0;
  }
  
  static int tmp464_probe_child_from_dt(struct device *dev,
  				      struct device_node *child,
  				      struct tmp464_data *data)
  
  {
  	struct regmap *regmap = data->regmap;
  	u32 channel;
  	s32 nfactor;
  	int err;
  
  	err = of_property_read_u32(child, "reg", &channel);
  	if (err) {
  		dev_err(dev, "missing reg property of %pOFn\n", child);
  		return err;
  	}
  
  	if (channel >= data->channels) {
  		dev_err(dev, "invalid reg %d of %pOFn\n", channel, child);
  		return -EINVAL;
  	}
  
  	of_property_read_string(child, "label", &data->channel[channel].label);
  
  	data->channel[channel].enabled = of_device_is_available(child);
  
  	err = of_property_read_s32(child, "ti,n-factor", &nfactor);
  	if (err && err != -EINVAL)
  		return err;
  	if (!err) {
  		if (channel == 0) {
  			dev_err(dev, "n-factor can't be set for internal channel\n");
  			return -EINVAL;
  		}
  		if (nfactor > 127 || nfactor < -128) {
  			dev_err(dev, "n-factor for channel %d invalid (%d)\n",
  				channel, nfactor);
  			return -EINVAL;
  		}
  		err = regmap_write(regmap, TMP464_N_FACTOR_REG(channel),
  				   (nfactor << 8) & 0xff00);
  		if (err)
  			return err;
  	}
  
  	return 0;
  }
  
  static int tmp464_probe_from_dt(struct device *dev, struct tmp464_data *data)
  {
  	const struct device_node *np = dev->of_node;
  	struct device_node *child;
  	int err;
  
  	for_each_child_of_node(np, child) {
  		if (strcmp(child->name, "channel"))
  			continue;
  
  		err = tmp464_probe_child_from_dt(dev, child, data);
  		if (err) {
  			of_node_put(child);
  			return err;
  		}
  	}
  
  	return 0;
  }
  
  static const struct hwmon_ops tmp464_ops = {
  	.is_visible = tmp464_is_visible,
  	.read = tmp464_read,
  	.read_string = tmp464_read_string,
  	.write = tmp464_write,
  };
  
  static const struct hwmon_channel_info *tmp464_info[] = {
  	HWMON_CHANNEL_INFO(chip,
  			   HWMON_C_UPDATE_INTERVAL),
  	HWMON_CHANNEL_INFO(temp,
  			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST | HWMON_T_CRIT |
  			   HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
  			   HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
  			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
  			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
  			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE),
  	NULL
  };
  
  static const struct hwmon_chip_info tmp464_chip_info = {
  	.ops = &tmp464_ops,
  	.info = tmp464_info,
  };
  
  /* regmap */
  
  static bool tmp464_is_volatile_reg(struct device *dev, unsigned int reg)
  {
  	return (reg < TMP464_TEMP_REG(TMP468_NUM_CHANNELS) ||
  		reg == TMP464_THERM_STATUS_REG ||
  		reg == TMP464_THERM2_STATUS_REG ||
  		reg == TMP464_REMOTE_OPEN_REG);
  }
  
  static const struct regmap_config tmp464_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 16,
  	.max_register = TMP464_DEVICE_ID_REG,
  	.volatile_reg = tmp464_is_volatile_reg,
  	.val_format_endian = REGMAP_ENDIAN_BIG,
  	.cache_type = REGCACHE_RBTREE,
  	.use_single_read = true,
  	.use_single_write = true,
  };
  
  static int tmp464_probe(struct i2c_client *client)
  {
  	struct device *dev = &client->dev;
  	struct device *hwmon_dev;
  	struct tmp464_data *data;
  	int i, err;
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) {
  		dev_err(&client->dev, "i2c functionality check failed\n");
  		return -ENODEV;
  	}
  	data = devm_kzalloc(dev, sizeof(struct tmp464_data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	mutex_init(&data->update_lock);
  
  	if (dev->of_node)
  		data->channels = (int)(unsigned long)of_device_get_match_data(&client->dev);
  	else
  		data->channels = i2c_match_id(tmp464_id, client)->driver_data;
  
  	data->regmap = devm_regmap_init_i2c(client, &tmp464_regmap_config);
  	if (IS_ERR(data->regmap))
  		return PTR_ERR(data->regmap);
  
  	for (i = 0; i < data->channels; i++)
  		data->channel[i].enabled = true;
  
  	err = tmp464_init_client(dev, data);
  	if (err)
  		return err;
  
  	if (dev->of_node) {
  		err = tmp464_probe_from_dt(dev, data);
  		if (err)
  			return err;
  	}
  
  	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
  							 data, &tmp464_chip_info, NULL);
  	return PTR_ERR_OR_ZERO(hwmon_dev);
  }
  
  static struct i2c_driver tmp464_driver = {
  	.class = I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "tmp464",
  		.of_match_table = of_match_ptr(tmp464_of_match),
  	},
  	.probe_new = tmp464_probe,
  	.id_table = tmp464_id,
  	.detect = tmp464_detect,
  	.address_list = normal_i2c,
  };
  
  module_i2c_driver(tmp464_driver);
  
  MODULE_AUTHOR("Agathe Porte <agathe.porte@nokia.com>");
  MODULE_DESCRIPTION("Texas Instruments TMP464 temperature sensor driver");
  MODULE_LICENSE("GPL");
  