v4.19.13 snapshot.
diff --git a/drivers/hwmon/ds1621.c b/drivers/hwmon/ds1621.c
new file mode 100644
index 0000000..5c317fc
--- /dev/null
+++ b/drivers/hwmon/ds1621.c
@@ -0,0 +1,409 @@
+/*
+ * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
+ *	      monitoring
+ * Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
+ * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
+ * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
+ * the help of Jean Delvare <jdelvare@suse.de>
+ *
+ * The DS1621 device is a digital temperature/thermometer with 9-bit
+ * resolution, a thermal alarm output (Tout), and user-defined minimum
+ * and maximum temperature thresholds (TH and TL).
+ *
+ * The DS1625, DS1631, DS1721, and DS1731 are pin compatible with the DS1621
+ * and similar in operation, with slight variations as noted in the device
+ * datasheets (please refer to www.maximintegrated.com for specific
+ * device information).
+ *
+ * Since the DS1621 was the first chipset supported by this driver,
+ * most comments will refer to this chipset, but are actually general
+ * and concern all supported chipsets, unless mentioned otherwise.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/sysfs.h>
+#include <linux/kernel.h>
+
+/* Supported devices */
+enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };
+
+/* Insmod parameters */
+static int polarity = -1;
+module_param(polarity, int, 0);
+MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
+
+/*
+ * The Configuration/Status register
+ *
+ * - DS1621:
+ *   7    6    5    4    3    2    1    0
+ * |Done|THF |TLF |NVB | X  | X  |POL |1SHOT|
+ *
+ * - DS1625:
+ *   7    6    5    4    3    2    1    0
+ * |Done|THF |TLF |NVB | 1  | 0  |POL |1SHOT|
+ *
+ * - DS1631, DS1731:
+ *   7    6    5    4    3    2    1    0
+ * |Done|THF |TLF |NVB | R1 | R0 |POL |1SHOT|
+ *
+ * - DS1721:
+ *   7    6    5    4    3    2    1    0
+ * |Done| X  | X  | U  | R1 | R0 |POL |1SHOT|
+ *
+ * Where:
+ * - 'X' is Reserved
+ * - 'U' is Undefined
+ */
+#define DS1621_REG_CONFIG_NVB		0x10
+#define DS1621_REG_CONFIG_RESOL		0x0C
+#define DS1621_REG_CONFIG_POLARITY	0x02
+#define DS1621_REG_CONFIG_1SHOT		0x01
+#define DS1621_REG_CONFIG_DONE		0x80
+
+#define DS1621_REG_CONFIG_RESOL_SHIFT	2
+
+/* ds1721 conversion rates: {C/LSB, time(ms), resolution bit setting} */
+static const unsigned short ds1721_convrates[] = {
+	94,	/*  9-bits (0.5,  93.75, RES[0..1] = 0 */
+	188,	/* 10-bits (0.25, 187.5, RES[0..1] = 1 */
+	375,	/* 11-bits (0.125,  375, RES[0..1] = 2 */
+	750,	/* 12-bits (0.0625, 750, RES[0..1] = 3 */
+};
+
+#define DS1621_CONVERSION_MAX	750
+#define DS1625_CONVERSION_MAX	500
+
+#define DS1621_TEMP_MAX	125000
+#define DS1621_TEMP_MIN	(-55000)
+
+/* The DS1621 temperature registers */
+static const u8 DS1621_REG_TEMP[3] = {
+	0xAA,		/* input, word, RO */
+	0xA2,		/* min, word, RW */
+	0xA1,		/* max, word, RW */
+};
+#define DS1621_REG_CONF			0xAC /* byte, RW */
+#define DS1621_COM_START		0xEE /* no data */
+#define DS1721_COM_START		0x51 /* no data */
+#define DS1621_COM_STOP			0x22 /* no data */
+
+/* The DS1621 configuration register */
+#define DS1621_ALARM_TEMP_HIGH		0x40
+#define DS1621_ALARM_TEMP_LOW		0x20
+
+/* Conversions */
+#define ALARMS_FROM_REG(val) ((val) & \
+			(DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
+
+/* Each client has this additional data */
+struct ds1621_data {
+	struct i2c_client *client;
+	struct mutex update_lock;
+	char valid;			/* !=0 if following fields are valid */
+	unsigned long last_updated;	/* In jiffies */
+	enum chips kind;		/* device type */
+
+	u16 temp[3];			/* Register values, word */
+	u8 conf;			/* Register encoding, combined */
+	u8 zbits;			/* Resolution encoded as number of
+					 * zero bits */
+	u16 update_interval;		/* Conversion rate in milliseconds */
+};
+
+static inline int DS1621_TEMP_FROM_REG(u16 reg)
+{
+	return DIV_ROUND_CLOSEST(((s16)reg / 16) * 625, 10);
+}
+
+/*
+ * TEMP: 0.001C/bit (-55C to +125C)
+ * REG:
+ *  - 1621, 1625: 0.5C/bit, 7 zero-bits
+ *  - 1631, 1721, 1731: 0.0625C/bit, 4 zero-bits
+ */
+static inline u16 DS1621_TEMP_TO_REG(long temp, u8 zbits)
+{
+	temp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);
+	temp = DIV_ROUND_CLOSEST(temp * (1 << (8 - zbits)), 1000) << zbits;
+	return temp;
+}
+
+static void ds1621_init_client(struct ds1621_data *data,
+			       struct i2c_client *client)
+{
+	u8 conf, new_conf, sreg, resol;
+
+	new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
+	/* switch to continuous conversion mode */
+	new_conf &= ~DS1621_REG_CONFIG_1SHOT;
+
+	/* setup output polarity */
+	if (polarity == 0)
+		new_conf &= ~DS1621_REG_CONFIG_POLARITY;
+	else if (polarity == 1)
+		new_conf |= DS1621_REG_CONFIG_POLARITY;
+
+	if (conf != new_conf)
+		i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
+
+	switch (data->kind) {
+	case ds1625:
+		data->update_interval = DS1625_CONVERSION_MAX;
+		data->zbits = 7;
+		sreg = DS1621_COM_START;
+		break;
+	case ds1631:
+	case ds1721:
+	case ds1731:
+		resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
+			 DS1621_REG_CONFIG_RESOL_SHIFT;
+		data->update_interval = ds1721_convrates[resol];
+		data->zbits = 7 - resol;
+		sreg = DS1721_COM_START;
+		break;
+	default:
+		data->update_interval = DS1621_CONVERSION_MAX;
+		data->zbits = 7;
+		sreg = DS1621_COM_START;
+		break;
+	}
+
+	/* start conversion */
+	i2c_smbus_write_byte(client, sreg);
+}
+
+static struct ds1621_data *ds1621_update_client(struct device *dev)
+{
+	struct ds1621_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	u8 new_conf;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + data->update_interval) ||
+	    !data->valid) {
+		int i;
+
+		dev_dbg(&client->dev, "Starting ds1621 update\n");
+
+		data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
+
+		for (i = 0; i < ARRAY_SIZE(data->temp); i++)
+			data->temp[i] = i2c_smbus_read_word_swapped(client,
+							 DS1621_REG_TEMP[i]);
+
+		/* reset alarms if necessary */
+		new_conf = data->conf;
+		if (data->temp[0] > data->temp[1])	/* input > min */
+			new_conf &= ~DS1621_ALARM_TEMP_LOW;
+		if (data->temp[0] < data->temp[2])	/* input < max */
+			new_conf &= ~DS1621_ALARM_TEMP_HIGH;
+		if (data->conf != new_conf)
+			i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
+						  new_conf);
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->update_lock);
+
+	return data;
+}
+
+static ssize_t show_temp(struct device *dev, struct device_attribute *da,
+			 char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ds1621_data *data = ds1621_update_client(dev);
+	return sprintf(buf, "%d\n",
+		       DS1621_TEMP_FROM_REG(data->temp[attr->index]));
+}
+
+static ssize_t set_temp(struct device *dev, struct device_attribute *da,
+			const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ds1621_data *data = dev_get_drvdata(dev);
+	long val;
+	int err;
+
+	err = kstrtol(buf, 10, &val);
+	if (err)
+		return err;
+
+	mutex_lock(&data->update_lock);
+	data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);
+	i2c_smbus_write_word_swapped(data->client, DS1621_REG_TEMP[attr->index],
+				     data->temp[attr->index]);
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+static ssize_t alarms_show(struct device *dev, struct device_attribute *da,
+			   char *buf)
+{
+	struct ds1621_data *data = ds1621_update_client(dev);
+	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
+}
+
+static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
+			  char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ds1621_data *data = ds1621_update_client(dev);
+	return sprintf(buf, "%d\n", !!(data->conf & attr->index));
+}
+
+static ssize_t update_interval_show(struct device *dev,
+				    struct device_attribute *da, char *buf)
+{
+	struct ds1621_data *data = dev_get_drvdata(dev);
+	return scnprintf(buf, PAGE_SIZE, "%hu\n", data->update_interval);
+}
+
+static ssize_t update_interval_store(struct device *dev,
+				     struct device_attribute *da,
+				     const char *buf, size_t count)
+{
+	struct ds1621_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long convrate;
+	s32 err;
+	int resol = 0;
+
+	err = kstrtoul(buf, 10, &convrate);
+	if (err)
+		return err;
+
+	/* Convert rate into resolution bits */
+	while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
+	       convrate > ds1721_convrates[resol])
+		resol++;
+
+	mutex_lock(&data->update_lock);
+	data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
+	data->conf &= ~DS1621_REG_CONFIG_RESOL;
+	data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
+	i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
+	data->update_interval = ds1721_convrates[resol];
+	data->zbits = 7 - resol;
+	mutex_unlock(&data->update_lock);
+
+	return count;
+}
+
+static DEVICE_ATTR_RO(alarms);
+static DEVICE_ATTR_RW(update_interval);
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
+static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
+		DS1621_ALARM_TEMP_LOW);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
+		DS1621_ALARM_TEMP_HIGH);
+
+static struct attribute *ds1621_attributes[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_max.dev_attr.attr,
+	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+	&dev_attr_alarms.attr,
+	&dev_attr_update_interval.attr,
+	NULL
+};
+
+static umode_t ds1621_attribute_visible(struct kobject *kobj,
+					struct attribute *attr, int index)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct ds1621_data *data = dev_get_drvdata(dev);
+
+	if (attr == &dev_attr_update_interval.attr)
+		if (data->kind == ds1621 || data->kind == ds1625)
+			/* shhh, we're hiding update_interval */
+			return 0;
+	return attr->mode;
+}
+
+static const struct attribute_group ds1621_group = {
+	.attrs = ds1621_attributes,
+	.is_visible = ds1621_attribute_visible
+};
+__ATTRIBUTE_GROUPS(ds1621);
+
+static int ds1621_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct ds1621_data *data;
+	struct device *hwmon_dev;
+
+	data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
+			    GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	mutex_init(&data->update_lock);
+
+	data->kind = id->driver_data;
+	data->client = client;
+
+	/* Initialize the DS1621 chip */
+	ds1621_init_client(data, client);
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
+							   client->name, data,
+							   ds1621_groups);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ds1621_id[] = {
+	{ "ds1621", ds1621 },
+	{ "ds1625", ds1625 },
+	{ "ds1631", ds1631 },
+	{ "ds1721", ds1721 },
+	{ "ds1731", ds1731 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ds1621_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ds1621_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "ds1621",
+	},
+	.probe		= ds1621_probe,
+	.id_table	= ds1621_id,
+};
+
+module_i2c_driver(ds1621_driver);
+
+MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
+MODULE_DESCRIPTION("DS1621 driver");
+MODULE_LICENSE("GPL");