Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2224 insertions, 0 deletions

diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
new file mode 100644
index 0000000000..c85e80c7e1
--- /dev/null
+++ b/drivers/w1/slaves/w1_therm.c
@@ -0,0 +1,2224 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	w1_therm.c
+ *
+ * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
+ */
+
+#include <asm/types.h>
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/hwmon.h>
+#include <linux/string.h>
+#include <linux/jiffies.h>
+
+#include <linux/w1.h>
+
+#define W1_THERM_DS18S20	0x10
+#define W1_THERM_DS1822		0x22
+#define W1_THERM_DS18B20	0x28
+#define W1_THERM_DS1825		0x3B
+#define W1_THERM_DS28EA00	0x42
+
+/*
+ * Allow the strong pullup to be disabled, but default to enabled.
+ * If it was disabled a parasite powered device might not get the require
+ * current to do a temperature conversion.  If it is enabled parasite powered
+ * devices have a better chance of getting the current required.
+ * In case the parasite power-detection is not working (seems to be the case
+ * for some DS18S20) the strong pullup can also be forced, regardless of the
+ * power state of the devices.
+ *
+ * Summary of options:
+ * - strong_pullup = 0	Disable strong pullup completely
+ * - strong_pullup = 1	Enable automatic strong pullup detection
+ * - strong_pullup = 2	Force strong pullup
+ */
+static int w1_strong_pullup = 1;
+module_param_named(strong_pullup, w1_strong_pullup, int, 0);
+
+/* Counter for devices supporting bulk reading */
+static u16 bulk_read_device_counter; /* =0 as per C standard */
+
+/* This command should be in public header w1.h but is not */
+#define W1_RECALL_EEPROM	0xB8
+
+/* Nb of try for an operation */
+#define W1_THERM_MAX_TRY		5
+
+/* ms delay to retry bus mutex */
+#define W1_THERM_RETRY_DELAY		20
+
+/* delay in ms to write in EEPROM */
+#define W1_THERM_EEPROM_WRITE_DELAY	10
+
+#define EEPROM_CMD_WRITE    "save"	/* cmd for write eeprom sysfs */
+#define EEPROM_CMD_READ     "restore"	/* cmd for read eeprom sysfs */
+#define BULK_TRIGGER_CMD    "trigger"	/* cmd to trigger a bulk read */
+
+#define MIN_TEMP	-55	/* min temperature that can be measured */
+#define MAX_TEMP	125	/* max temperature that can be measured */
+
+/* Allowed values for sysfs conv_time attribute */
+#define CONV_TIME_DEFAULT 0
+#define CONV_TIME_MEASURE 1
+
+/* Bits in sysfs "features" value */
+#define W1_THERM_CHECK_RESULT 1	/* Enable conversion success check */
+#define W1_THERM_POLL_COMPLETION 2	/* Poll for conversion completion */
+#define W1_THERM_FEATURES_MASK 3		/* All values mask */
+
+/* Poll period in milliseconds. Should be less then a shortest operation on the device */
+#define W1_POLL_PERIOD 32
+#define W1_POLL_CONVERT_TEMP 2000	/* Timeout for W1_CONVERT_TEMP, ms */
+#define W1_POLL_RECALL_EEPROM 500	/* Timeout for W1_RECALL_EEPROM, ms*/
+
+/* Masks for resolution functions, work with all devices */
+/* Bit mask for config register for all devices, bits 7,6,5 */
+#define W1_THERM_RESOLUTION_MASK 0xE0
+/* Bit offset of resolution in config register for all devices */
+#define W1_THERM_RESOLUTION_SHIFT 5
+/* Bit offset of resolution in config register for all devices */
+#define W1_THERM_RESOLUTION_SHIFT 5
+/* Add this to bit value to get resolution */
+#define W1_THERM_RESOLUTION_MIN 9
+/* Maximum allowed value */
+#define W1_THERM_RESOLUTION_MAX 14
+
+/* Helpers Macros */
+
+/*
+ * return a pointer on the slave w1_therm_family_converter struct:
+ * always test family data existence before using this macro
+ */
+#define SLAVE_SPECIFIC_FUNC(sl) \
+	(((struct w1_therm_family_data *)(sl->family_data))->specific_functions)
+
+/*
+ * return the power mode of the sl slave : 1-ext, 0-parasite, <0 unknown
+ * always test family data existence before using this macro
+ */
+#define SLAVE_POWERMODE(sl) \
+	(((struct w1_therm_family_data *)(sl->family_data))->external_powered)
+
+/*
+ * return the resolution in bit of the sl slave : <0 unknown
+ * always test family data existence before using this macro
+ */
+#define SLAVE_RESOLUTION(sl) \
+	(((struct w1_therm_family_data *)(sl->family_data))->resolution)
+
+/*
+ * return the conv_time_override of the sl slave
+ * always test family data existence before using this macro
+ */
+ #define SLAVE_CONV_TIME_OVERRIDE(sl) \
+	(((struct w1_therm_family_data *)(sl->family_data))->conv_time_override)
+
+/*
+ * return the features of the sl slave
+ * always test family data existence before using this macro
+ */
+ #define SLAVE_FEATURES(sl) \
+	(((struct w1_therm_family_data *)(sl->family_data))->features)
+
+/*
+ * return whether or not a converT command has been issued to the slave
+ * * 0: no bulk read is pending
+ * * -1: conversion is in progress
+ * * 1: conversion done, result to be read
+ */
+#define SLAVE_CONVERT_TRIGGERED(sl) \
+	(((struct w1_therm_family_data *)(sl->family_data))->convert_triggered)
+
+/* return the address of the refcnt in the family data */
+#define THERM_REFCNT(family_data) \
+	(&((struct w1_therm_family_data *)family_data)->refcnt)
+
+/* Structs definition */
+
+/**
+ * struct w1_therm_family_converter - bind device specific functions
+ * @broken: flag for non-registred families
+ * @reserved: not used here
+ * @f: pointer to the device binding structure
+ * @convert: pointer to the device conversion function
+ * @get_conversion_time: pointer to the device conversion time function
+ * @set_resolution: pointer to the device set_resolution function
+ * @get_resolution: pointer to the device get_resolution function
+ * @write_data: pointer to the device writing function (2 or 3 bytes)
+ * @bulk_read: true if device family support bulk read, false otherwise
+ */
+struct w1_therm_family_converter {
+	u8		broken;
+	u16		reserved;
+	struct w1_family	*f;
+	int		(*convert)(u8 rom[9]);
+	int		(*get_conversion_time)(struct w1_slave *sl);
+	int		(*set_resolution)(struct w1_slave *sl, int val);
+	int		(*get_resolution)(struct w1_slave *sl);
+	int		(*write_data)(struct w1_slave *sl, const u8 *data);
+	bool		bulk_read;
+};
+
+/**
+ * struct w1_therm_family_data - device data
+ * @rom: ROM device id (64bit Lasered ROM code + 1 CRC byte)
+ * @refcnt: ref count
+ * @external_powered:	1 device powered externally,
+ *				0 device parasite powered,
+ *				-x error or undefined
+ * @resolution: current device resolution
+ * @convert_triggered: conversion state of the device
+ * @conv_time_override: user selected conversion time or CONV_TIME_DEFAULT
+ * @features: bit mask - enable temperature validity check, poll for completion
+ * @specific_functions: pointer to struct of device specific function
+ */
+struct w1_therm_family_data {
+	uint8_t rom[9];
+	atomic_t refcnt;
+	int external_powered;
+	int resolution;
+	int convert_triggered;
+	int conv_time_override;
+	unsigned int features;
+	struct w1_therm_family_converter *specific_functions;
+};
+
+/**
+ * struct therm_info - store temperature reading
+ * @rom: read device data (8 data bytes + 1 CRC byte)
+ * @crc: computed crc from rom
+ * @verdict: 1 crc checked, 0 crc not matching
+ */
+struct therm_info {
+	u8 rom[9];
+	u8 crc;
+	u8 verdict;
+};
+
+/* Hardware Functions declaration */
+
+/**
+ * reset_select_slave() - reset and select a slave
+ * @sl: the slave to select
+ *
+ * Resets the bus and select the slave by sending a ROM MATCH cmd
+ * w1_reset_select_slave() from w1_io.c could not be used here because
+ * it sent a SKIP ROM command if only one device is on the line.
+ * At the beginning of the such process, sl->master->slave_count is 1 even if
+ * more devices are on the line, causing collision on the line.
+ *
+ * Context: The w1 master lock must be held.
+ *
+ * Return: 0 if success, negative kernel error code otherwise.
+ */
+static int reset_select_slave(struct w1_slave *sl);
+
+/**
+ * convert_t() - Query the device for temperature conversion and read
+ * @sl: pointer to the slave to read
+ * @info: pointer to a structure to store the read results
+ *
+ * Return: 0 if success, -kernel error code otherwise
+ */
+static int convert_t(struct w1_slave *sl, struct therm_info *info);
+
+/**
+ * read_scratchpad() - read the data in device RAM
+ * @sl: pointer to the slave to read
+ * @info: pointer to a structure to store the read results
+ *
+ * Return: 0 if success, -kernel error code otherwise
+ */
+static int read_scratchpad(struct w1_slave *sl, struct therm_info *info);
+
+/**
+ * write_scratchpad() - write nb_bytes in the device RAM
+ * @sl: pointer to the slave to write in
+ * @data: pointer to an array of 3 bytes, as 3 bytes MUST be written
+ * @nb_bytes: number of bytes to be written (2 for DS18S20, 3 otherwise)
+ *
+ * Return: 0 if success, -kernel error code otherwise
+ */
+static int write_scratchpad(struct w1_slave *sl, const u8 *data, u8 nb_bytes);
+
+/**
+ * copy_scratchpad() - Copy the content of scratchpad in device EEPROM
+ * @sl: slave involved
+ *
+ * Return: 0 if success, -kernel error code otherwise
+ */
+static int copy_scratchpad(struct w1_slave *sl);
+
+/**
+ * recall_eeprom() - Restore EEPROM data to device RAM
+ * @sl: slave involved
+ *
+ * Return: 0 if success, -kernel error code otherwise
+ */
+static int recall_eeprom(struct w1_slave *sl);
+
+/**
+ * read_powermode() - Query the power mode of the slave
+ * @sl: slave to retrieve the power mode
+ *
+ * Ask the device to get its power mode (external or parasite)
+ * and store the power status in the &struct w1_therm_family_data.
+ *
+ * Return:
+ * * 0 parasite powered device
+ * * 1 externally powered device
+ * * <0 kernel error code
+ */
+static int read_powermode(struct w1_slave *sl);
+
+/**
+ * trigger_bulk_read() - function to trigger a bulk read on the bus
+ * @dev_master: the device master of the bus
+ *
+ * Send a SKIP ROM follow by a CONVERT T command on the bus.
+ * It also set the status flag in each slave &struct w1_therm_family_data
+ * to signal that a conversion is in progress.
+ *
+ * Return: 0 if success, -kernel error code otherwise
+ */
+static int trigger_bulk_read(struct w1_master *dev_master);
+
+/* Sysfs interface declaration */
+
+static ssize_t w1_slave_show(struct device *device,
+	struct device_attribute *attr, char *buf);
+
+static ssize_t w1_slave_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size);
+
+static ssize_t w1_seq_show(struct device *device,
+	struct device_attribute *attr, char *buf);
+
+static ssize_t temperature_show(struct device *device,
+	struct device_attribute *attr, char *buf);
+
+static ssize_t ext_power_show(struct device *device,
+	struct device_attribute *attr, char *buf);
+
+static ssize_t resolution_show(struct device *device,
+	struct device_attribute *attr, char *buf);
+
+static ssize_t resolution_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size);
+
+static ssize_t eeprom_cmd_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size);
+
+static ssize_t alarms_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size);
+
+static ssize_t alarms_show(struct device *device,
+	struct device_attribute *attr, char *buf);
+
+static ssize_t therm_bulk_read_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size);
+
+static ssize_t therm_bulk_read_show(struct device *device,
+	struct device_attribute *attr, char *buf);
+
+static ssize_t conv_time_show(struct device *device,
+			      struct device_attribute *attr, char *buf);
+
+static ssize_t conv_time_store(struct device *device,
+			       struct device_attribute *attr, const char *buf,
+			       size_t size);
+
+static ssize_t features_show(struct device *device,
+			      struct device_attribute *attr, char *buf);
+
+static ssize_t features_store(struct device *device,
+			       struct device_attribute *attr, const char *buf,
+			       size_t size);
+/* Attributes declarations */
+
+static DEVICE_ATTR_RW(w1_slave);
+static DEVICE_ATTR_RO(w1_seq);
+static DEVICE_ATTR_RO(temperature);
+static DEVICE_ATTR_RO(ext_power);
+static DEVICE_ATTR_RW(resolution);
+static DEVICE_ATTR_WO(eeprom_cmd);
+static DEVICE_ATTR_RW(alarms);
+static DEVICE_ATTR_RW(conv_time);
+static DEVICE_ATTR_RW(features);
+
+static DEVICE_ATTR_RW(therm_bulk_read); /* attribut at master level */
+
+/* Interface Functions declaration */
+
+/**
+ * w1_therm_add_slave() - Called when a new slave is discovered
+ * @sl: slave just discovered by the master.
+ *
+ * Called by the master when the slave is discovered on the bus. Used to
+ * initialize slave state before the beginning of any communication.
+ *
+ * Return: 0 - If success, negative kernel code otherwise
+ */
+static int w1_therm_add_slave(struct w1_slave *sl);
+
+/**
+ * w1_therm_remove_slave() - Called when a slave is removed
+ * @sl: slave to be removed.
+ *
+ * Called by the master when the slave is considered not to be on the bus
+ * anymore. Used to free memory.
+ */
+static void w1_therm_remove_slave(struct w1_slave *sl);
+
+/* Family attributes */
+
+static struct attribute *w1_therm_attrs[] = {
+	&dev_attr_w1_slave.attr,
+	&dev_attr_temperature.attr,
+	&dev_attr_ext_power.attr,
+	&dev_attr_resolution.attr,
+	&dev_attr_eeprom_cmd.attr,
+	&dev_attr_alarms.attr,
+	&dev_attr_conv_time.attr,
+	&dev_attr_features.attr,
+	NULL,
+};
+
+static struct attribute *w1_ds18s20_attrs[] = {
+	&dev_attr_w1_slave.attr,
+	&dev_attr_temperature.attr,
+	&dev_attr_ext_power.attr,
+	&dev_attr_eeprom_cmd.attr,
+	&dev_attr_alarms.attr,
+	&dev_attr_conv_time.attr,
+	&dev_attr_features.attr,
+	NULL,
+};
+
+static struct attribute *w1_ds28ea00_attrs[] = {
+	&dev_attr_w1_slave.attr,
+	&dev_attr_w1_seq.attr,
+	&dev_attr_temperature.attr,
+	&dev_attr_ext_power.attr,
+	&dev_attr_resolution.attr,
+	&dev_attr_eeprom_cmd.attr,
+	&dev_attr_alarms.attr,
+	&dev_attr_conv_time.attr,
+	&dev_attr_features.attr,
+	NULL,
+};
+
+/* Attribute groups */
+
+ATTRIBUTE_GROUPS(w1_therm);
+ATTRIBUTE_GROUPS(w1_ds18s20);
+ATTRIBUTE_GROUPS(w1_ds28ea00);
+
+#if IS_REACHABLE(CONFIG_HWMON)
+static int w1_read_temp(struct device *dev, u32 attr, int channel,
+			long *val);
+
+static umode_t w1_is_visible(const void *_data, enum hwmon_sensor_types type,
+			     u32 attr, int channel)
+{
+	return attr == hwmon_temp_input ? 0444 : 0;
+}
+
+static int w1_read(struct device *dev, enum hwmon_sensor_types type,
+		   u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_temp:
+		return w1_read_temp(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static const u32 w1_temp_config[] = {
+	HWMON_T_INPUT,
+	0
+};
+
+static const struct hwmon_channel_info w1_temp = {
+	.type = hwmon_temp,
+	.config = w1_temp_config,
+};
+
+static const struct hwmon_channel_info * const w1_info[] = {
+	&w1_temp,
+	NULL
+};
+
+static const struct hwmon_ops w1_hwmon_ops = {
+	.is_visible = w1_is_visible,
+	.read = w1_read,
+};
+
+static const struct hwmon_chip_info w1_chip_info = {
+	.ops = &w1_hwmon_ops,
+	.info = w1_info,
+};
+#define W1_CHIPINFO	(&w1_chip_info)
+#else
+#define W1_CHIPINFO	NULL
+#endif
+
+/* Family operations */
+
+static const struct w1_family_ops w1_therm_fops = {
+	.add_slave	= w1_therm_add_slave,
+	.remove_slave	= w1_therm_remove_slave,
+	.groups		= w1_therm_groups,
+	.chip_info	= W1_CHIPINFO,
+};
+
+static const struct w1_family_ops w1_ds18s20_fops = {
+	.add_slave	= w1_therm_add_slave,
+	.remove_slave	= w1_therm_remove_slave,
+	.groups		= w1_ds18s20_groups,
+	.chip_info	= W1_CHIPINFO,
+};
+
+static const struct w1_family_ops w1_ds28ea00_fops = {
+	.add_slave	= w1_therm_add_slave,
+	.remove_slave	= w1_therm_remove_slave,
+	.groups		= w1_ds28ea00_groups,
+	.chip_info	= W1_CHIPINFO,
+};
+
+/* Family binding operations struct */
+
+static struct w1_family w1_therm_family_DS18S20 = {
+	.fid = W1_THERM_DS18S20,
+	.fops = &w1_ds18s20_fops,
+};
+
+static struct w1_family w1_therm_family_DS18B20 = {
+	.fid = W1_THERM_DS18B20,
+	.fops = &w1_therm_fops,
+};
+
+static struct w1_family w1_therm_family_DS1822 = {
+	.fid = W1_THERM_DS1822,
+	.fops = &w1_therm_fops,
+};
+
+static struct w1_family w1_therm_family_DS28EA00 = {
+	.fid = W1_THERM_DS28EA00,
+	.fops = &w1_ds28ea00_fops,
+};
+
+static struct w1_family w1_therm_family_DS1825 = {
+	.fid = W1_THERM_DS1825,
+	.fops = &w1_therm_fops,
+};
+
+/* Device dependent func */
+
+static inline int w1_DS18B20_convert_time(struct w1_slave *sl)
+{
+	int ret;
+
+	if (!sl->family_data)
+		return -ENODEV;	/* device unknown */
+
+	if (SLAVE_CONV_TIME_OVERRIDE(sl) != CONV_TIME_DEFAULT)
+		return SLAVE_CONV_TIME_OVERRIDE(sl);
+
+	/* Return the conversion time, depending on resolution,
+	 * select maximum conversion time among all compatible devices
+	 */
+	switch (SLAVE_RESOLUTION(sl)) {
+	case 9:
+		ret = 95;
+		break;
+	case 10:
+		ret = 190;
+		break;
+	case 11:
+		ret = 375;
+		break;
+	case 12:
+		ret = 750;
+		break;
+	case 13:
+		ret = 850;  /* GX20MH01 only. Datasheet says 500ms, but that's not enough. */
+		break;
+	case 14:
+		ret = 1600; /* GX20MH01 only. Datasheet says 1000ms - not enough */
+		break;
+	default:
+		ret = 750;
+	}
+	return ret;
+}
+
+static inline int w1_DS18S20_convert_time(struct w1_slave *sl)
+{
+	if (!sl->family_data)
+		return -ENODEV;	/* device unknown */
+
+	if (SLAVE_CONV_TIME_OVERRIDE(sl) == CONV_TIME_DEFAULT)
+		return 750; /* default for DS18S20 */
+	else
+		return SLAVE_CONV_TIME_OVERRIDE(sl);
+}
+
+static inline int w1_DS1825_convert_time(struct w1_slave *sl)
+{
+	int ret;
+
+	if (!sl->family_data)
+		return -ENODEV;	/* device unknown */
+
+	if (SLAVE_CONV_TIME_OVERRIDE(sl) != CONV_TIME_DEFAULT)
+		return SLAVE_CONV_TIME_OVERRIDE(sl);
+
+	/* Return the conversion time, depending on resolution,
+	 * select maximum conversion time among all compatible devices
+	 */
+	switch (SLAVE_RESOLUTION(sl)) {
+	case 9:
+		ret = 95;
+		break;
+	case 10:
+		ret = 190;
+		break;
+	case 11:
+		ret = 375;
+		break;
+	case 12:
+		ret = 750;
+		break;
+	case 14:
+		ret = 100; /* MAX31850 only. Datasheet says 100ms  */
+		break;
+	default:
+		ret = 750;
+	}
+	return ret;
+}
+
+static inline int w1_DS18B20_write_data(struct w1_slave *sl,
+				const u8 *data)
+{
+	return write_scratchpad(sl, data, 3);
+}
+
+static inline int w1_DS18S20_write_data(struct w1_slave *sl,
+				const u8 *data)
+{
+	/* No config register */
+	return write_scratchpad(sl, data, 2);
+}
+
+static inline int w1_DS18B20_set_resolution(struct w1_slave *sl, int val)
+{
+	int ret;
+	struct therm_info info, info2;
+
+	/* DS18B20 resolution is 9 to 12 bits */
+	/* GX20MH01 resolution is 9 to 14 bits */
+	/* MAX31850 resolution is fixed 14 bits */
+	if (val < W1_THERM_RESOLUTION_MIN || val > W1_THERM_RESOLUTION_MAX)
+		return -EINVAL;
+
+	/* Calc bit value from resolution */
+	val = (val - W1_THERM_RESOLUTION_MIN) << W1_THERM_RESOLUTION_SHIFT;
+
+	/*
+	 * Read the scratchpad to change only the required bits
+	 * (bit5 & bit 6 from byte 4)
+	 */
+	ret = read_scratchpad(sl, &info);
+
+	if (ret)
+		return ret;
+
+
+	info.rom[4] &= ~W1_THERM_RESOLUTION_MASK;
+	info.rom[4] |= val;
+
+	/* Write data in the device RAM */
+	ret = w1_DS18B20_write_data(sl, info.rom + 2);
+	if (ret)
+		return ret;
+
+	/* Have to read back the resolution to verify an actual value
+	 * GX20MH01 and DS18B20 are indistinguishable by family number, but resolutions differ
+	 * Some DS18B20 clones don't support resolution change
+	 */
+	ret = read_scratchpad(sl, &info2);
+	if (ret)
+		/* Scratchpad read fail */
+		return ret;
+
+	if ((info2.rom[4] & W1_THERM_RESOLUTION_MASK) == (info.rom[4] & W1_THERM_RESOLUTION_MASK))
+		return 0;
+
+	/* Resolution verify error */
+	return -EIO;
+}
+
+static inline int w1_DS18B20_get_resolution(struct w1_slave *sl)
+{
+	int ret;
+	int resolution;
+	struct therm_info info;
+
+	ret = read_scratchpad(sl, &info);
+
+	if (ret)
+		return ret;
+
+	resolution = ((info.rom[4] & W1_THERM_RESOLUTION_MASK) >> W1_THERM_RESOLUTION_SHIFT)
+		+ W1_THERM_RESOLUTION_MIN;
+	/* GX20MH01 has one special case:
+	 *   >=14 means 14 bits when getting resolution from bit value.
+	 * MAX31850 delivers fixed 15 and has 14 bits.
+	 * Other devices have no more then 12 bits.
+	 */
+	if (resolution > W1_THERM_RESOLUTION_MAX)
+		resolution = W1_THERM_RESOLUTION_MAX;
+
+	return resolution;
+}
+
+/**
+ * w1_DS18B20_convert_temp() - temperature computation for DS18B20
+ * @rom: data read from device RAM (8 data bytes + 1 CRC byte)
+ *
+ * Can be called for any DS18B20 compliant device.
+ *
+ * Return: value in millidegrees Celsius.
+ */
+static inline int w1_DS18B20_convert_temp(u8 rom[9])
+{
+	u16 bv;
+	s16 t;
+
+	/* Signed 16-bit value to unsigned, cpu order */
+	bv = le16_to_cpup((__le16 *)rom);
+
+	/* Config register bit R2 = 1 - GX20MH01 in 13 or 14 bit resolution mode */
+	if (rom[4] & 0x80) {
+		/* Insert two temperature bits from config register */
+		/* Avoid arithmetic shift of signed value */
+		bv = (bv << 2) | (rom[4] & 3);
+		t = (s16) bv;	/* Degrees, lowest bit is 2^-6 */
+		return (int)t * 1000 / 64;	/* Sign-extend to int; millidegrees */
+	}
+	t = (s16)bv;	/* Degrees, lowest bit is 2^-4 */
+	return (int)t * 1000 / 16;	/* Sign-extend to int; millidegrees */
+}
+
+/**
+ * w1_DS18S20_convert_temp() - temperature computation for DS18S20
+ * @rom: data read from device RAM (8 data bytes + 1 CRC byte)
+ *
+ * Can be called for any DS18S20 compliant device.
+ *
+ * Return: value in millidegrees Celsius.
+ */
+static inline int w1_DS18S20_convert_temp(u8 rom[9])
+{
+	int t, h;
+
+	if (!rom[7]) {
+		pr_debug("%s: Invalid argument for conversion\n", __func__);
+		return 0;
+	}
+
+	if (rom[1] == 0)
+		t = ((s32)rom[0] >> 1)*1000;
+	else
+		t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
+
+	t -= 250;
+	h = 1000*((s32)rom[7] - (s32)rom[6]);
+	h /= (s32)rom[7];
+	t += h;
+
+	return t;
+}
+
+/**
+ * w1_DS1825_convert_temp() - temperature computation for DS1825
+ * @rom: data read from device RAM (8 data bytes + 1 CRC byte)
+ *
+ * Can be called for any DS1825 compliant device.
+ * Is used by MAX31850, too
+ *
+ * Return: value in millidegrees Celsius.
+ */
+
+static inline int w1_DS1825_convert_temp(u8 rom[9])
+{
+	u16 bv;
+	s16 t;
+
+	/* Signed 16-bit value to unsigned, cpu order */
+	bv = le16_to_cpup((__le16 *)rom);
+
+	/* Config register bit 7 = 1 - MA31850 found, 14 bit resolution */
+	if (rom[4] & 0x80) {
+		/* Mask out bits 0 (Fault) and 1 (Reserved) */
+		/* Avoid arithmetic shift of signed value */
+		bv = (bv & 0xFFFC); /* Degrees, lowest 4 bits are 2^-1, 2^-2 and 2 zero bits */
+	}
+	t = (s16)bv;	/* Degrees, lowest bit is 2^-4 */
+	return (int)t * 1000 / 16;	/* Sign-extend to int; millidegrees */
+}
+
+/* Device capability description */
+/* GX20MH01 device shares family number and structure with DS18B20 */
+
+static struct w1_therm_family_converter w1_therm_families[] = {
+	{
+		.f				= &w1_therm_family_DS18S20,
+		.convert			= w1_DS18S20_convert_temp,
+		.get_conversion_time	= w1_DS18S20_convert_time,
+		.set_resolution		= NULL,	/* no config register */
+		.get_resolution		= NULL,	/* no config register */
+		.write_data			= w1_DS18S20_write_data,
+		.bulk_read			= true
+	},
+	{
+		.f				= &w1_therm_family_DS1822,
+		.convert			= w1_DS18B20_convert_temp,
+		.get_conversion_time	= w1_DS18B20_convert_time,
+		.set_resolution		= w1_DS18B20_set_resolution,
+		.get_resolution		= w1_DS18B20_get_resolution,
+		.write_data			= w1_DS18B20_write_data,
+		.bulk_read			= true
+	},
+	{
+		/* Also used for GX20MH01 */
+		.f				= &w1_therm_family_DS18B20,
+		.convert			= w1_DS18B20_convert_temp,
+		.get_conversion_time	= w1_DS18B20_convert_time,
+		.set_resolution		= w1_DS18B20_set_resolution,
+		.get_resolution		= w1_DS18B20_get_resolution,
+		.write_data			= w1_DS18B20_write_data,
+		.bulk_read			= true
+	},
+	{
+		.f				= &w1_therm_family_DS28EA00,
+		.convert			= w1_DS18B20_convert_temp,
+		.get_conversion_time	= w1_DS18B20_convert_time,
+		.set_resolution		= w1_DS18B20_set_resolution,
+		.get_resolution		= w1_DS18B20_get_resolution,
+		.write_data			= w1_DS18B20_write_data,
+		.bulk_read			= false
+	},
+	{
+		/* Also used for MAX31850 */
+		.f				= &w1_therm_family_DS1825,
+		.convert			= w1_DS1825_convert_temp,
+		.get_conversion_time	= w1_DS1825_convert_time,
+		.set_resolution		= w1_DS18B20_set_resolution,
+		.get_resolution		= w1_DS18B20_get_resolution,
+		.write_data			= w1_DS18B20_write_data,
+		.bulk_read			= true
+	}
+};
+
+/* Helpers Functions */
+
+/**
+ * device_family() - Retrieve a pointer on &struct w1_therm_family_converter
+ * @sl: slave to retrieve the device specific structure
+ *
+ * Return: pointer to the slaves's family converter, NULL if not known
+ */
+static struct w1_therm_family_converter *device_family(struct w1_slave *sl)
+{
+	struct w1_therm_family_converter *ret = NULL;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
+		if (w1_therm_families[i].f->fid == sl->family->fid) {
+			ret = &w1_therm_families[i];
+			break;
+		}
+	}
+	return ret;
+}
+
+/**
+ * bus_mutex_lock() - Acquire the mutex
+ * @lock: w1 bus mutex to acquire
+ *
+ * It try to acquire the mutex W1_THERM_MAX_TRY times and wait
+ * W1_THERM_RETRY_DELAY between 2 attempts.
+ *
+ * Return: true is mutex is acquired and lock, false otherwise
+ */
+static inline bool bus_mutex_lock(struct mutex *lock)
+{
+	int max_trying = W1_THERM_MAX_TRY;
+
+	/* try to acquire the mutex, if not, sleep retry_delay before retry) */
+	while (mutex_lock_interruptible(lock) != 0 && max_trying > 0) {
+		unsigned long sleep_rem;
+
+		sleep_rem = msleep_interruptible(W1_THERM_RETRY_DELAY);
+		if (!sleep_rem)
+			max_trying--;
+	}
+
+	if (!max_trying)
+		return false;	/* Didn't acquire the bus mutex */
+
+	return true;
+}
+
+/**
+ * check_family_data() - Check if family data and specific functions are present
+ * @sl: W1 device data
+ *
+ * Return: 0 - OK, negative value - error
+ */
+static int check_family_data(struct w1_slave *sl)
+{
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(&sl->dev,
+			 "%s: Device is not supported by the driver\n", __func__);
+		return -EINVAL;  /* No device family */
+	}
+	return 0;
+}
+
+/**
+ * bulk_read_support() - check if slave support bulk read
+ * @sl: device to check the ability
+ *
+ * Return: true if bulk read is supported, false if not or error
+ */
+static inline bool bulk_read_support(struct w1_slave *sl)
+{
+	if (SLAVE_SPECIFIC_FUNC(sl))
+		return SLAVE_SPECIFIC_FUNC(sl)->bulk_read;
+
+	dev_info(&sl->dev,
+		"%s: Device not supported by the driver\n", __func__);
+
+	return false;  /* No device family */
+}
+
+/**
+ * conversion_time() - get the Tconv for the slave
+ * @sl: device to get the conversion time
+ *
+ * On device supporting resolution settings, conversion time depend
+ * on the resolution setting. This helper function get the slave timing,
+ * depending on its current setting.
+ *
+ * Return: conversion time in ms, negative values are kernel error code
+ */
+static inline int conversion_time(struct w1_slave *sl)
+{
+	if (SLAVE_SPECIFIC_FUNC(sl))
+		return SLAVE_SPECIFIC_FUNC(sl)->get_conversion_time(sl);
+
+	dev_info(&sl->dev,
+		"%s: Device not supported by the driver\n", __func__);
+
+	return -ENODEV;  /* No device family */
+}
+
+/**
+ * temperature_from_RAM() - Convert the read info to temperature
+ * @sl: device that sent the RAM data
+ * @rom: read value on the slave device RAM
+ *
+ * Device dependent, the function bind the correct computation method.
+ *
+ * Return: temperature in 1/1000degC, 0 on error.
+ */
+static inline int temperature_from_RAM(struct w1_slave *sl, u8 rom[9])
+{
+	if (SLAVE_SPECIFIC_FUNC(sl))
+		return SLAVE_SPECIFIC_FUNC(sl)->convert(rom);
+
+	dev_info(&sl->dev,
+		"%s: Device not supported by the driver\n", __func__);
+
+	return 0;  /* No device family */
+}
+
+/**
+ * int_to_short() - Safe casting of int to short
+ *
+ * @i: integer to be converted to short
+ *
+ * Device register use 1 byte to store signed integer.
+ * This helper function convert the int in a signed short,
+ * using the min/max values that device can measure as limits.
+ * min/max values are defined by macro.
+ *
+ * Return: a short in the range of min/max value
+ */
+static inline s8 int_to_short(int i)
+{
+	/* Prepare to cast to short by eliminating out of range values */
+	i = clamp(i, MIN_TEMP, MAX_TEMP);
+	return (s8) i;
+}
+
+/* Interface Functions */
+
+static int w1_therm_add_slave(struct w1_slave *sl)
+{
+	struct w1_therm_family_converter *sl_family_conv;
+
+	/* Allocate memory */
+	sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
+		GFP_KERNEL);
+	if (!sl->family_data)
+		return -ENOMEM;
+
+	atomic_set(THERM_REFCNT(sl->family_data), 1);
+
+	/* Get a pointer to the device specific function struct */
+	sl_family_conv = device_family(sl);
+	if (!sl_family_conv) {
+		kfree(sl->family_data);
+		return -ENODEV;
+	}
+	/* save this pointer to the device structure */
+	SLAVE_SPECIFIC_FUNC(sl) = sl_family_conv;
+
+	if (bulk_read_support(sl)) {
+		/*
+		 * add the sys entry to trigger bulk_read
+		 * at master level only the 1st time
+		 */
+		if (!bulk_read_device_counter) {
+			int err = device_create_file(&sl->master->dev,
+				&dev_attr_therm_bulk_read);
+
+			if (err)
+				dev_warn(&sl->dev,
+				"%s: Device has been added, but bulk read is unavailable. err=%d\n",
+				__func__, err);
+		}
+		/* Increment the counter */
+		bulk_read_device_counter++;
+	}
+
+	/* Getting the power mode of the device {external, parasite} */
+	SLAVE_POWERMODE(sl) = read_powermode(sl);
+
+	if (SLAVE_POWERMODE(sl) < 0) {
+		/* no error returned as device has been added */
+		dev_warn(&sl->dev,
+			"%s: Device has been added, but power_mode may be corrupted. err=%d\n",
+			 __func__, SLAVE_POWERMODE(sl));
+	}
+
+	/* Getting the resolution of the device */
+	if (SLAVE_SPECIFIC_FUNC(sl)->get_resolution) {
+		SLAVE_RESOLUTION(sl) =
+			SLAVE_SPECIFIC_FUNC(sl)->get_resolution(sl);
+		if (SLAVE_RESOLUTION(sl) < 0) {
+			/* no error returned as device has been added */
+			dev_warn(&sl->dev,
+				"%s:Device has been added, but resolution may be corrupted. err=%d\n",
+				__func__, SLAVE_RESOLUTION(sl));
+		}
+	}
+
+	/* Finally initialize convert_triggered flag */
+	SLAVE_CONVERT_TRIGGERED(sl) = 0;
+
+	return 0;
+}
+
+static void w1_therm_remove_slave(struct w1_slave *sl)
+{
+	int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data));
+
+	if (bulk_read_support(sl)) {
+		bulk_read_device_counter--;
+		/* Delete the entry if no more device support the feature */
+		if (!bulk_read_device_counter)
+			device_remove_file(&sl->master->dev,
+				&dev_attr_therm_bulk_read);
+	}
+
+	while (refcnt) {
+		msleep(1000);
+		refcnt = atomic_read(THERM_REFCNT(sl->family_data));
+	}
+	kfree(sl->family_data);
+	sl->family_data = NULL;
+}
+
+/* Hardware Functions */
+
+/* Safe version of reset_select_slave - avoid using the one in w_io.c */
+static int reset_select_slave(struct w1_slave *sl)
+{
+	u8 match[9] = { W1_MATCH_ROM, };
+	u64 rn = le64_to_cpu(*((u64 *)&sl->reg_num));
+
+	if (w1_reset_bus(sl->master))
+		return -ENODEV;
+
+	memcpy(&match[1], &rn, 8);
+	w1_write_block(sl->master, match, 9);
+
+	return 0;
+}
+
+/**
+ * w1_poll_completion - Poll for operation completion, with timeout
+ * @dev_master: the device master of the bus
+ * @tout_ms: timeout in milliseconds
+ *
+ * The device is answering 0's while an operation is in progress and 1's after it completes
+ * Timeout may happen if the previous command was not recognised due to a line noise
+ *
+ * Return: 0 - OK, negative error - timeout
+ */
+static int w1_poll_completion(struct w1_master *dev_master, int tout_ms)
+{
+	int i;
+
+	for (i = 0; i < tout_ms/W1_POLL_PERIOD; i++) {
+		/* Delay is before poll, for device to recognize a command */
+		msleep(W1_POLL_PERIOD);
+
+		/* Compare all 8 bits to mitigate a noise on the bus */
+		if (w1_read_8(dev_master) == 0xFF)
+			break;
+	}
+	if (i == tout_ms/W1_POLL_PERIOD)
+		return -EIO;
+
+	return 0;
+}
+
+static int convert_t(struct w1_slave *sl, struct therm_info *info)
+{
+	struct w1_master *dev_master = sl->master;
+	int max_trying = W1_THERM_MAX_TRY;
+	int t_conv;
+	int ret = -ENODEV;
+	bool strong_pullup;
+
+	if (!sl->family_data)
+		goto error;
+
+	strong_pullup = (w1_strong_pullup == 2 ||
+					(!SLAVE_POWERMODE(sl) &&
+					w1_strong_pullup));
+
+	if (strong_pullup && SLAVE_FEATURES(sl) & W1_THERM_POLL_COMPLETION) {
+		dev_warn(&sl->dev,
+			"%s: Disabling W1_THERM_POLL_COMPLETION in parasite power mode.\n",
+			__func__);
+		SLAVE_FEATURES(sl) &= ~W1_THERM_POLL_COMPLETION;
+	}
+
+	/* get conversion duration device and id dependent */
+	t_conv = conversion_time(sl);
+
+	memset(info->rom, 0, sizeof(info->rom));
+
+	/* prevent the slave from going away in sleep */
+	atomic_inc(THERM_REFCNT(sl->family_data));
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto dec_refcnt;
+	}
+
+	while (max_trying-- && ret) { /* ret should be 0 */
+
+		info->verdict = 0;
+		info->crc = 0;
+		/* safe version to select slave */
+		if (!reset_select_slave(sl)) {
+			unsigned long sleep_rem;
+
+			/* 750ms strong pullup (or delay) after the convert */
+			if (strong_pullup)
+				w1_next_pullup(dev_master, t_conv);
+
+			w1_write_8(dev_master, W1_CONVERT_TEMP);
+
+			if (SLAVE_FEATURES(sl) & W1_THERM_POLL_COMPLETION) {
+				ret = w1_poll_completion(dev_master, W1_POLL_CONVERT_TEMP);
+				if (ret) {
+					dev_dbg(&sl->dev, "%s: Timeout\n", __func__);
+					goto mt_unlock;
+				}
+				mutex_unlock(&dev_master->bus_mutex);
+			} else if (!strong_pullup) { /*no device need pullup */
+				sleep_rem = msleep_interruptible(t_conv);
+				if (sleep_rem != 0) {
+					ret = -EINTR;
+					goto mt_unlock;
+				}
+				mutex_unlock(&dev_master->bus_mutex);
+			} else { /*some device need pullup */
+				mutex_unlock(&dev_master->bus_mutex);
+				sleep_rem = msleep_interruptible(t_conv);
+				if (sleep_rem != 0) {
+					ret = -EINTR;
+					goto dec_refcnt;
+				}
+			}
+			ret = read_scratchpad(sl, info);
+
+			/* If enabled, check for conversion success */
+			if ((SLAVE_FEATURES(sl) & W1_THERM_CHECK_RESULT) &&
+				(info->rom[6] == 0xC) &&
+				((info->rom[1] == 0x5 && info->rom[0] == 0x50) ||
+				(info->rom[1] == 0x7 && info->rom[0] == 0xFF))
+			) {
+				/* Invalid reading (scratchpad byte 6 = 0xC)
+				 * due to insufficient conversion time
+				 * or power failure.
+				 */
+				ret = -EIO;
+			}
+
+			goto dec_refcnt;
+		}
+
+	}
+
+mt_unlock:
+	mutex_unlock(&dev_master->bus_mutex);
+dec_refcnt:
+	atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+	return ret;
+}
+
+static int conv_time_measure(struct w1_slave *sl, int *conv_time)
+{
+	struct therm_info inf,
+		*info = &inf;
+	struct w1_master *dev_master = sl->master;
+	int max_trying = W1_THERM_MAX_TRY;
+	int ret = -ENODEV;
+	bool strong_pullup;
+
+	if (!sl->family_data)
+		goto error;
+
+	strong_pullup = (w1_strong_pullup == 2 ||
+		(!SLAVE_POWERMODE(sl) &&
+		w1_strong_pullup));
+
+	if (strong_pullup) {
+		pr_info("%s: Measure with strong_pullup is not supported.\n", __func__);
+		return -EINVAL;
+	}
+
+	memset(info->rom, 0, sizeof(info->rom));
+
+	/* prevent the slave from going away in sleep */
+	atomic_inc(THERM_REFCNT(sl->family_data));
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto dec_refcnt;
+	}
+
+	while (max_trying-- && ret) { /* ret should be 0 */
+		info->verdict = 0;
+		info->crc = 0;
+		/* safe version to select slave */
+		if (!reset_select_slave(sl)) {
+			int j_start, j_end;
+
+			/*no device need pullup */
+			w1_write_8(dev_master, W1_CONVERT_TEMP);
+
+			j_start = jiffies;
+			ret = w1_poll_completion(dev_master, W1_POLL_CONVERT_TEMP);
+			if (ret) {
+				dev_dbg(&sl->dev, "%s: Timeout\n", __func__);
+				goto mt_unlock;
+			}
+			j_end = jiffies;
+			/* 1.2x increase for variation and changes over temperature range */
+			*conv_time = jiffies_to_msecs(j_end-j_start)*12/10;
+			pr_debug("W1 Measure complete, conv_time = %d, HZ=%d.\n",
+				*conv_time, HZ);
+			if (*conv_time <= CONV_TIME_MEASURE) {
+				ret = -EIO;
+				goto mt_unlock;
+			}
+			mutex_unlock(&dev_master->bus_mutex);
+			ret = read_scratchpad(sl, info);
+			goto dec_refcnt;
+		}
+
+	}
+mt_unlock:
+	mutex_unlock(&dev_master->bus_mutex);
+dec_refcnt:
+	atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+	return ret;
+}
+
+static int read_scratchpad(struct w1_slave *sl, struct therm_info *info)
+{
+	struct w1_master *dev_master = sl->master;
+	int max_trying = W1_THERM_MAX_TRY;
+	int ret = -ENODEV;
+
+	info->verdict = 0;
+
+	if (!sl->family_data)
+		goto error;
+
+	memset(info->rom, 0, sizeof(info->rom));
+
+	/* prevent the slave from going away in sleep */
+	atomic_inc(THERM_REFCNT(sl->family_data));
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto dec_refcnt;
+	}
+
+	while (max_trying-- && ret) { /* ret should be 0 */
+		/* safe version to select slave */
+		if (!reset_select_slave(sl)) {
+			u8 nb_bytes_read;
+
+			w1_write_8(dev_master, W1_READ_SCRATCHPAD);
+
+			nb_bytes_read = w1_read_block(dev_master, info->rom, 9);
+			if (nb_bytes_read != 9) {
+				dev_warn(&sl->dev,
+					"w1_read_block(): returned %u instead of 9.\n",
+					nb_bytes_read);
+				ret = -EIO;
+			}
+
+			info->crc = w1_calc_crc8(info->rom, 8);
+
+			if (info->rom[8] == info->crc) {
+				info->verdict = 1;
+				ret = 0;
+			} else
+				ret = -EIO; /* CRC not checked */
+		}
+
+	}
+	mutex_unlock(&dev_master->bus_mutex);
+
+dec_refcnt:
+	atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+	return ret;
+}
+
+static int write_scratchpad(struct w1_slave *sl, const u8 *data, u8 nb_bytes)
+{
+	struct w1_master *dev_master = sl->master;
+	int max_trying = W1_THERM_MAX_TRY;
+	int ret = -ENODEV;
+
+	if (!sl->family_data)
+		goto error;
+
+	/* prevent the slave from going away in sleep */
+	atomic_inc(THERM_REFCNT(sl->family_data));
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto dec_refcnt;
+	}
+
+	while (max_trying-- && ret) { /* ret should be 0 */
+		/* safe version to select slave */
+		if (!reset_select_slave(sl)) {
+			w1_write_8(dev_master, W1_WRITE_SCRATCHPAD);
+			w1_write_block(dev_master, data, nb_bytes);
+			ret = 0;
+		}
+	}
+	mutex_unlock(&dev_master->bus_mutex);
+
+dec_refcnt:
+	atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+	return ret;
+}
+
+static int copy_scratchpad(struct w1_slave *sl)
+{
+	struct w1_master *dev_master = sl->master;
+	int max_trying = W1_THERM_MAX_TRY;
+	int t_write, ret = -ENODEV;
+	bool strong_pullup;
+
+	if (!sl->family_data)
+		goto error;
+
+	t_write = W1_THERM_EEPROM_WRITE_DELAY;
+	strong_pullup = (w1_strong_pullup == 2 ||
+					(!SLAVE_POWERMODE(sl) &&
+					w1_strong_pullup));
+
+	/* prevent the slave from going away in sleep */
+	atomic_inc(THERM_REFCNT(sl->family_data));
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto dec_refcnt;
+	}
+
+	while (max_trying-- && ret) { /* ret should be 0 */
+		/* safe version to select slave */
+		if (!reset_select_slave(sl)) {
+			unsigned long sleep_rem;
+
+			/* 10ms strong pullup (or delay) after the convert */
+			if (strong_pullup)
+				w1_next_pullup(dev_master, t_write);
+
+			w1_write_8(dev_master, W1_COPY_SCRATCHPAD);
+
+			if (strong_pullup) {
+				sleep_rem = msleep_interruptible(t_write);
+				if (sleep_rem != 0) {
+					ret = -EINTR;
+					goto mt_unlock;
+				}
+			}
+			ret = 0;
+		}
+
+	}
+
+mt_unlock:
+	mutex_unlock(&dev_master->bus_mutex);
+dec_refcnt:
+	atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+	return ret;
+}
+
+static int recall_eeprom(struct w1_slave *sl)
+{
+	struct w1_master *dev_master = sl->master;
+	int max_trying = W1_THERM_MAX_TRY;
+	int ret = -ENODEV;
+
+	if (!sl->family_data)
+		goto error;
+
+	/* prevent the slave from going away in sleep */
+	atomic_inc(THERM_REFCNT(sl->family_data));
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto dec_refcnt;
+	}
+
+	while (max_trying-- && ret) { /* ret should be 0 */
+		/* safe version to select slave */
+		if (!reset_select_slave(sl)) {
+
+			w1_write_8(dev_master, W1_RECALL_EEPROM);
+			ret = w1_poll_completion(dev_master, W1_POLL_RECALL_EEPROM);
+		}
+
+	}
+
+	mutex_unlock(&dev_master->bus_mutex);
+
+dec_refcnt:
+	atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+	return ret;
+}
+
+static int read_powermode(struct w1_slave *sl)
+{
+	struct w1_master *dev_master = sl->master;
+	int max_trying = W1_THERM_MAX_TRY;
+	int  ret = -ENODEV;
+
+	if (!sl->family_data)
+		goto error;
+
+	/* prevent the slave from going away in sleep */
+	atomic_inc(THERM_REFCNT(sl->family_data));
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto dec_refcnt;
+	}
+
+	while ((max_trying--) && (ret < 0)) {
+		/* safe version to select slave */
+		if (!reset_select_slave(sl)) {
+			w1_write_8(dev_master, W1_READ_PSUPPLY);
+			/*
+			 * Emit a read time slot and read only one bit,
+			 * 1 is externally powered,
+			 * 0 is parasite powered
+			 */
+			ret = w1_touch_bit(dev_master, 1);
+			/* ret should be either 1 either 0 */
+		}
+	}
+	mutex_unlock(&dev_master->bus_mutex);
+
+dec_refcnt:
+	atomic_dec(THERM_REFCNT(sl->family_data));
+error:
+	return ret;
+}
+
+static int trigger_bulk_read(struct w1_master *dev_master)
+{
+	struct w1_slave *sl = NULL; /* used to iterate through slaves */
+	int max_trying = W1_THERM_MAX_TRY;
+	int t_conv = 0;
+	int ret = -ENODEV;
+	bool strong_pullup = false;
+
+	/*
+	 * Check whether there are parasite powered device on the bus,
+	 * and compute duration of conversion for these devices
+	 * so we can apply a strong pullup if required
+	 */
+	list_for_each_entry(sl, &dev_master->slist, w1_slave_entry) {
+		if (!sl->family_data)
+			goto error;
+		if (bulk_read_support(sl)) {
+			int t_cur = conversion_time(sl);
+
+			t_conv = max(t_cur, t_conv);
+			strong_pullup = strong_pullup ||
+					(w1_strong_pullup == 2 ||
+					(!SLAVE_POWERMODE(sl) &&
+					w1_strong_pullup));
+		}
+	}
+
+	/*
+	 * t_conv is the max conversion time required on the bus
+	 * If its 0, no device support the bulk read feature
+	 */
+	if (!t_conv)
+		goto error;
+
+	if (!bus_mutex_lock(&dev_master->bus_mutex)) {
+		ret = -EAGAIN;	/* Didn't acquire the mutex */
+		goto error;
+	}
+
+	while ((max_trying--) && (ret < 0)) { /* ret should be either 0 */
+
+		if (!w1_reset_bus(dev_master)) {	/* Just reset the bus */
+			unsigned long sleep_rem;
+
+			w1_write_8(dev_master, W1_SKIP_ROM);
+
+			if (strong_pullup)	/* Apply pullup if required */
+				w1_next_pullup(dev_master, t_conv);
+
+			w1_write_8(dev_master, W1_CONVERT_TEMP);
+
+			/* set a flag to instruct that converT pending */
+			list_for_each_entry(sl,
+				&dev_master->slist, w1_slave_entry) {
+				if (bulk_read_support(sl))
+					SLAVE_CONVERT_TRIGGERED(sl) = -1;
+			}
+
+			if (strong_pullup) { /* some device need pullup */
+				sleep_rem = msleep_interruptible(t_conv);
+				if (sleep_rem != 0) {
+					ret = -EINTR;
+					goto mt_unlock;
+				}
+				mutex_unlock(&dev_master->bus_mutex);
+			} else {
+				mutex_unlock(&dev_master->bus_mutex);
+				sleep_rem = msleep_interruptible(t_conv);
+				if (sleep_rem != 0) {
+					ret = -EINTR;
+					goto set_flag;
+				}
+			}
+			ret = 0;
+			goto set_flag;
+		}
+	}
+
+mt_unlock:
+	mutex_unlock(&dev_master->bus_mutex);
+set_flag:
+	/* set a flag to register convsersion is done */
+	list_for_each_entry(sl, &dev_master->slist, w1_slave_entry) {
+		if (bulk_read_support(sl))
+			SLAVE_CONVERT_TRIGGERED(sl) = 1;
+	}
+error:
+	return ret;
+}
+
+/* Sysfs Interface definition */
+
+static ssize_t w1_slave_show(struct device *device,
+			     struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	struct therm_info info;
+	u8 *family_data = sl->family_data;
+	int ret, i;
+	ssize_t c = PAGE_SIZE;
+
+	if (bulk_read_support(sl)) {
+		if (SLAVE_CONVERT_TRIGGERED(sl) < 0) {
+			dev_dbg(device,
+				"%s: Conversion in progress, retry later\n",
+				__func__);
+			return 0;
+		} else if (SLAVE_CONVERT_TRIGGERED(sl) > 0) {
+			/* A bulk read has been issued, read the device RAM */
+			ret = read_scratchpad(sl, &info);
+			SLAVE_CONVERT_TRIGGERED(sl) = 0;
+		} else
+			ret = convert_t(sl, &info);
+	} else
+		ret = convert_t(sl, &info);
+
+	if (ret < 0) {
+		dev_dbg(device,
+			"%s: Temperature data may be corrupted. err=%d\n",
+			__func__, ret);
+		return 0;
+	}
+
+	for (i = 0; i < 9; ++i)
+		c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", info.rom[i]);
+	c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
+		      info.crc, (info.verdict) ? "YES" : "NO");
+
+	if (info.verdict)
+		memcpy(family_data, info.rom, sizeof(info.rom));
+	else
+		dev_warn(device, "%s:Read failed CRC check\n", __func__);
+
+	for (i = 0; i < 9; ++i)
+		c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
+			      ((u8 *)family_data)[i]);
+
+	c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
+			temperature_from_RAM(sl, info.rom));
+
+	ret = PAGE_SIZE - c;
+	return ret;
+}
+
+static ssize_t w1_slave_store(struct device *device,
+			      struct device_attribute *attr, const char *buf,
+			      size_t size)
+{
+	int val, ret = 0;
+	struct w1_slave *sl = dev_to_w1_slave(device);
+
+	ret = kstrtoint(buf, 10, &val); /* converting user entry to int */
+
+	if (ret) {	/* conversion error */
+		dev_info(device,
+			"%s: conversion error. err= %d\n", __func__, ret);
+		return size;	/* return size to avoid call back again */
+	}
+
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(device,
+			"%s: Device not supported by the driver\n", __func__);
+		return size;  /* No device family */
+	}
+
+	if (val == 0)	/* val=0 : trigger a EEPROM save */
+		ret = copy_scratchpad(sl);
+	else {
+		if (SLAVE_SPECIFIC_FUNC(sl)->set_resolution)
+			ret = SLAVE_SPECIFIC_FUNC(sl)->set_resolution(sl, val);
+	}
+
+	if (ret) {
+		dev_warn(device, "%s: Set resolution - error %d\n", __func__, ret);
+		/* Propagate error to userspace */
+		return ret;
+	}
+	SLAVE_RESOLUTION(sl) = val;
+	/* Reset the conversion time to default - it depends on resolution */
+	SLAVE_CONV_TIME_OVERRIDE(sl) = CONV_TIME_DEFAULT;
+
+	return size; /* always return size to avoid infinite calling */
+}
+
+static ssize_t temperature_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	struct therm_info info;
+	int ret = 0;
+
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(device,
+			"%s: Device not supported by the driver\n", __func__);
+		return 0;  /* No device family */
+	}
+
+	if (bulk_read_support(sl)) {
+		if (SLAVE_CONVERT_TRIGGERED(sl) < 0) {
+			dev_dbg(device,
+				"%s: Conversion in progress, retry later\n",
+				__func__);
+			return 0;
+		} else if (SLAVE_CONVERT_TRIGGERED(sl) > 0) {
+			/* A bulk read has been issued, read the device RAM */
+			ret = read_scratchpad(sl, &info);
+			SLAVE_CONVERT_TRIGGERED(sl) = 0;
+		} else
+			ret = convert_t(sl, &info);
+	} else
+		ret = convert_t(sl, &info);
+
+	if (ret < 0) {
+		dev_dbg(device,
+			"%s: Temperature data may be corrupted. err=%d\n",
+			__func__, ret);
+		return 0;
+	}
+
+	return sprintf(buf, "%d\n", temperature_from_RAM(sl, info.rom));
+}
+
+static ssize_t ext_power_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+
+	if (!sl->family_data) {
+		dev_info(device,
+			"%s: Device not supported by the driver\n", __func__);
+		return 0;  /* No device family */
+	}
+
+	/* Getting the power mode of the device {external, parasite} */
+	SLAVE_POWERMODE(sl) = read_powermode(sl);
+
+	if (SLAVE_POWERMODE(sl) < 0) {
+		dev_dbg(device,
+			"%s: Power_mode may be corrupted. err=%d\n",
+			__func__, SLAVE_POWERMODE(sl));
+	}
+	return sprintf(buf, "%d\n", SLAVE_POWERMODE(sl));
+}
+
+static ssize_t resolution_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(device,
+			"%s: Device not supported by the driver\n", __func__);
+		return 0;  /* No device family */
+	}
+
+	/* get the correct function depending on the device */
+	SLAVE_RESOLUTION(sl) = SLAVE_SPECIFIC_FUNC(sl)->get_resolution(sl);
+	if (SLAVE_RESOLUTION(sl) < 0) {
+		dev_dbg(device,
+			"%s: Resolution may be corrupted. err=%d\n",
+			__func__, SLAVE_RESOLUTION(sl));
+	}
+
+	return sprintf(buf, "%d\n", SLAVE_RESOLUTION(sl));
+}
+
+static ssize_t resolution_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	int val;
+	int ret = 0;
+
+	ret = kstrtoint(buf, 10, &val); /* converting user entry to int */
+
+	if (ret) {	/* conversion error */
+		dev_info(device,
+			"%s: conversion error. err= %d\n", __func__, ret);
+		return size;	/* return size to avoid call back again */
+	}
+
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(device,
+			"%s: Device not supported by the driver\n", __func__);
+		return size;  /* No device family */
+	}
+
+	/*
+	 * Don't deal with the val enterd by user,
+	 * only device knows what is correct or not
+	 */
+
+	/* get the correct function depending on the device */
+	ret = SLAVE_SPECIFIC_FUNC(sl)->set_resolution(sl, val);
+
+	if (ret)
+		return ret;
+
+	SLAVE_RESOLUTION(sl) = val;
+	/* Reset the conversion time to default because it depends on resolution */
+	SLAVE_CONV_TIME_OVERRIDE(sl) = CONV_TIME_DEFAULT;
+
+	return size;
+}
+
+static ssize_t eeprom_cmd_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	int ret = -EINVAL; /* Invalid argument */
+
+	if (size == sizeof(EEPROM_CMD_WRITE)) {
+		if (!strncmp(buf, EEPROM_CMD_WRITE, sizeof(EEPROM_CMD_WRITE)-1))
+			ret = copy_scratchpad(sl);
+	} else if (size == sizeof(EEPROM_CMD_READ)) {
+		if (!strncmp(buf, EEPROM_CMD_READ, sizeof(EEPROM_CMD_READ)-1))
+			ret = recall_eeprom(sl);
+	}
+
+	if (ret)
+		dev_info(device, "%s: error in process %d\n", __func__, ret);
+
+	return size;
+}
+
+static ssize_t alarms_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	int ret;
+	s8 th = 0, tl = 0;
+	struct therm_info scratchpad;
+
+	ret = read_scratchpad(sl, &scratchpad);
+
+	if (!ret)	{
+		th = scratchpad.rom[2]; /* TH is byte 2 */
+		tl = scratchpad.rom[3]; /* TL is byte 3 */
+	} else {
+		dev_info(device,
+			"%s: error reading alarms register %d\n",
+			__func__, ret);
+	}
+
+	return sprintf(buf, "%hd %hd\n", tl, th);
+}
+
+static ssize_t alarms_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	struct therm_info info;
+	u8 new_config_register[3];	/* array of data to be written */
+	int temp, ret;
+	char *token = NULL;
+	s8 tl, th;	/* 1 byte per value + temp ring order */
+	char *p_args, *orig;
+
+	p_args = orig = kmalloc(size, GFP_KERNEL);
+	/* Safe string copys as buf is const */
+	if (!p_args) {
+		dev_warn(device,
+			"%s: error unable to allocate memory %d\n",
+			__func__, -ENOMEM);
+		return size;
+	}
+	strcpy(p_args, buf);
+
+	/* Split string using space char */
+	token = strsep(&p_args, " ");
+
+	if (!token)	{
+		dev_info(device,
+			"%s: error parsing args %d\n", __func__, -EINVAL);
+		goto free_m;
+	}
+
+	/* Convert 1st entry to int */
+	ret = kstrtoint (token, 10, &temp);
+	if (ret) {
+		dev_info(device,
+			"%s: error parsing args %d\n", __func__, ret);
+		goto free_m;
+	}
+
+	tl = int_to_short(temp);
+
+	/* Split string using space char */
+	token = strsep(&p_args, " ");
+	if (!token)	{
+		dev_info(device,
+			"%s: error parsing args %d\n", __func__, -EINVAL);
+		goto free_m;
+	}
+	/* Convert 2nd entry to int */
+	ret = kstrtoint (token, 10, &temp);
+	if (ret) {
+		dev_info(device,
+			"%s: error parsing args %d\n", __func__, ret);
+		goto free_m;
+	}
+
+	/* Prepare to cast to short by eliminating out of range values */
+	th = int_to_short(temp);
+
+	/* Reorder if required th and tl */
+	if (tl > th)
+		swap(tl, th);
+
+	/*
+	 * Read the scratchpad to change only the required bits
+	 * (th : byte 2 - tl: byte 3)
+	 */
+	ret = read_scratchpad(sl, &info);
+	if (!ret) {
+		new_config_register[0] = th;	/* Byte 2 */
+		new_config_register[1] = tl;	/* Byte 3 */
+		new_config_register[2] = info.rom[4];/* Byte 4 */
+	} else {
+		dev_info(device,
+			"%s: error reading from the slave device %d\n",
+			__func__, ret);
+		goto free_m;
+	}
+
+	/* Write data in the device RAM */
+	if (!SLAVE_SPECIFIC_FUNC(sl)) {
+		dev_info(device,
+			"%s: Device not supported by the driver %d\n",
+			__func__, -ENODEV);
+		goto free_m;
+	}
+
+	ret = SLAVE_SPECIFIC_FUNC(sl)->write_data(sl, new_config_register);
+	if (ret)
+		dev_info(device,
+			"%s: error writing to the slave device %d\n",
+			__func__, ret);
+
+free_m:
+	/* free allocated memory */
+	kfree(orig);
+
+	return size;
+}
+
+static ssize_t therm_bulk_read_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct w1_master *dev_master = dev_to_w1_master(device);
+	int ret = -EINVAL; /* Invalid argument */
+
+	if (size == sizeof(BULK_TRIGGER_CMD))
+		if (!strncmp(buf, BULK_TRIGGER_CMD,
+				sizeof(BULK_TRIGGER_CMD)-1))
+			ret = trigger_bulk_read(dev_master);
+
+	if (ret)
+		dev_info(device,
+			"%s: unable to trigger a bulk read on the bus. err=%d\n",
+			__func__, ret);
+
+	return size;
+}
+
+static ssize_t therm_bulk_read_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_master *dev_master = dev_to_w1_master(device);
+	struct w1_slave *sl = NULL;
+	int ret = 0;
+
+	list_for_each_entry(sl, &dev_master->slist, w1_slave_entry) {
+		if (sl->family_data) {
+			if (bulk_read_support(sl)) {
+				if (SLAVE_CONVERT_TRIGGERED(sl) == -1) {
+					ret = -1;
+					goto show_result;
+				}
+				if (SLAVE_CONVERT_TRIGGERED(sl) == 1)
+					/* continue to check other slaves */
+					ret = 1;
+			}
+		}
+	}
+show_result:
+	return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t conv_time_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(device,
+			"%s: Device is not supported by the driver\n", __func__);
+		return 0;  /* No device family */
+	}
+	return sprintf(buf, "%d\n", conversion_time(sl));
+}
+
+static ssize_t conv_time_store(struct device *device,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	int val, ret = 0;
+	struct w1_slave *sl = dev_to_w1_slave(device);
+
+	if (kstrtoint(buf, 10, &val)) /* converting user entry to int */
+		return -EINVAL;
+
+	if (check_family_data(sl))
+		return -ENODEV;
+
+	if (val != CONV_TIME_MEASURE) {
+		if (val >= CONV_TIME_DEFAULT)
+			SLAVE_CONV_TIME_OVERRIDE(sl) = val;
+		else
+			return -EINVAL;
+
+	} else {
+		int conv_time;
+
+		ret = conv_time_measure(sl, &conv_time);
+		if (ret)
+			return -EIO;
+		SLAVE_CONV_TIME_OVERRIDE(sl) = conv_time;
+	}
+	return size;
+}
+
+static ssize_t features_show(struct device *device,
+			     struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(device,
+			 "%s: Device not supported by the driver\n", __func__);
+		return 0;  /* No device family */
+	}
+	return sprintf(buf, "%u\n", SLAVE_FEATURES(sl));
+}
+
+static ssize_t features_store(struct device *device,
+			      struct device_attribute *attr, const char *buf, size_t size)
+{
+	int val, ret = 0;
+	bool strong_pullup;
+	struct w1_slave *sl = dev_to_w1_slave(device);
+
+	ret = kstrtouint(buf, 10, &val); /* converting user entry to int */
+	if (ret)
+		return -EINVAL;  /* invalid number */
+
+	if ((!sl->family_data) || (!SLAVE_SPECIFIC_FUNC(sl))) {
+		dev_info(device, "%s: Device not supported by the driver\n", __func__);
+		return -ENODEV;
+	}
+
+	if ((val & W1_THERM_FEATURES_MASK) != val)
+		return -EINVAL;
+
+	SLAVE_FEATURES(sl) = val;
+
+	strong_pullup = (w1_strong_pullup == 2 ||
+			 (!SLAVE_POWERMODE(sl) &&
+			  w1_strong_pullup));
+
+	if (strong_pullup && SLAVE_FEATURES(sl) & W1_THERM_POLL_COMPLETION) {
+		dev_warn(&sl->dev,
+			 "%s: W1_THERM_POLL_COMPLETION disabled in parasite power mode.\n",
+			 __func__);
+		SLAVE_FEATURES(sl) &= ~W1_THERM_POLL_COMPLETION;
+	}
+
+	return size;
+}
+
+#if IS_REACHABLE(CONFIG_HWMON)
+static int w1_read_temp(struct device *device, u32 attr, int channel,
+			long *val)
+{
+	struct w1_slave *sl = dev_get_drvdata(device);
+	struct therm_info info;
+	int ret;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		ret = convert_t(sl, &info);
+		if (ret)
+			return ret;
+
+		if (!info.verdict) {
+			ret = -EIO;
+			return ret;
+		}
+
+		*val = temperature_from_RAM(sl, info.rom);
+		ret = 0;
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+}
+#endif
+
+#define W1_42_CHAIN	0x99
+#define W1_42_CHAIN_OFF	0x3C
+#define W1_42_CHAIN_OFF_INV	0xC3
+#define W1_42_CHAIN_ON	0x5A
+#define W1_42_CHAIN_ON_INV	0xA5
+#define W1_42_CHAIN_DONE 0x96
+#define W1_42_CHAIN_DONE_INV 0x69
+#define W1_42_COND_READ	0x0F
+#define W1_42_SUCCESS_CONFIRM_BYTE 0xAA
+#define W1_42_FINISHED_BYTE 0xFF
+static ssize_t w1_seq_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct w1_slave *sl = dev_to_w1_slave(device);
+	ssize_t c = PAGE_SIZE;
+	int i;
+	u8 ack;
+	u64 rn;
+	struct w1_reg_num *reg_num;
+	int seq = 0;
+
+	mutex_lock(&sl->master->bus_mutex);
+	/* Place all devices in CHAIN state */
+	if (w1_reset_bus(sl->master))
+		goto error;
+	w1_write_8(sl->master, W1_SKIP_ROM);
+	w1_write_8(sl->master, W1_42_CHAIN);
+	w1_write_8(sl->master, W1_42_CHAIN_ON);
+	w1_write_8(sl->master, W1_42_CHAIN_ON_INV);
+	msleep(sl->master->pullup_duration);
+
+	/* check for acknowledgment */
+	ack = w1_read_8(sl->master);
+	if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
+		goto error;
+
+	/* In case the bus fails to send 0xFF, limit */
+	for (i = 0; i <= 64; i++) {
+		if (w1_reset_bus(sl->master))
+			goto error;
+
+		w1_write_8(sl->master, W1_42_COND_READ);
+		w1_read_block(sl->master, (u8 *)&rn, 8);
+		reg_num = (struct w1_reg_num *) &rn;
+		if (reg_num->family == W1_42_FINISHED_BYTE)
+			break;
+		if (sl->reg_num.id == reg_num->id)
+			seq = i;
+
+		if (w1_reset_bus(sl->master))
+			goto error;
+
+		/* Put the device into chain DONE state */
+		w1_write_8(sl->master, W1_MATCH_ROM);
+		w1_write_block(sl->master, (u8 *)&rn, 8);
+		w1_write_8(sl->master, W1_42_CHAIN);
+		w1_write_8(sl->master, W1_42_CHAIN_DONE);
+		w1_write_8(sl->master, W1_42_CHAIN_DONE_INV);
+
+		/* check for acknowledgment */
+		ack = w1_read_8(sl->master);
+		if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
+			goto error;
+	}
+
+	/* Exit from CHAIN state */
+	if (w1_reset_bus(sl->master))
+		goto error;
+	w1_write_8(sl->master, W1_SKIP_ROM);
+	w1_write_8(sl->master, W1_42_CHAIN);
+	w1_write_8(sl->master, W1_42_CHAIN_OFF);
+	w1_write_8(sl->master, W1_42_CHAIN_OFF_INV);
+
+	/* check for acknowledgment */
+	ack = w1_read_8(sl->master);
+	if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
+		goto error;
+	mutex_unlock(&sl->master->bus_mutex);
+
+	c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq);
+	return PAGE_SIZE - c;
+error:
+	mutex_unlock(&sl->master->bus_mutex);
+	return -EIO;
+}
+
+static int __init w1_therm_init(void)
+{
+	int err, i;
+
+	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
+		err = w1_register_family(w1_therm_families[i].f);
+		if (err)
+			w1_therm_families[i].broken = 1;
+	}
+
+	return 0;
+}
+
+static void __exit w1_therm_fini(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
+		if (!w1_therm_families[i].broken)
+			w1_unregister_family(w1_therm_families[i].f);
+}
+
+module_init(w1_therm_init);
+module_exit(w1_therm_fini);
+
+MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
+MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
+MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));