hwmon: add support for JEDEC JC 42.4 compliant temperature sensors
Guenter Roeck [Tue, 10 Aug 2010 00:21:08 +0000 (17:21 -0700)]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/hwmon/jc42 [new file with mode: 0644]
MAINTAINERS
drivers/hwmon/Kconfig
drivers/hwmon/Makefile
drivers/hwmon/jc42.c [new file with mode: 0644]

diff --git a/Documentation/hwmon/jc42 b/Documentation/hwmon/jc42
new file mode 100644 (file)
index 0000000..0e76ef1
--- /dev/null
@@ -0,0 +1,97 @@
+Kernel driver jc42
+==================
+
+Supported chips:
+  * Analog Devices ADT7408
+    Prefix: 'adt7408'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+       http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf
+  * IDT TSE2002B3, TS3000B3
+    Prefix: 'tse2002b3', 'ts3000b3'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+       http://www.idt.com/products/getdoc.cfm?docid=18715691
+       http://www.idt.com/products/getdoc.cfm?docid=18715692
+  * Maxim MAX6604
+    Prefix: 'max6604'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+       http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
+  * Microchip MCP9805, MCP98242, MCP98243, MCP9843
+    Prefixes: 'mcp9805', 'mcp98242', 'mcp98243', 'mcp9843'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+       http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf
+       http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf
+       http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf
+  * NXP Semiconductors SE97, SE97B
+    Prefix: 'se97'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+       http://www.nxp.com/documents/data_sheet/SE97.pdf
+       http://www.nxp.com/documents/data_sheet/SE97B.pdf
+  * NXP Semiconductors SE98
+    Prefix: 'se98'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+       http://www.nxp.com/documents/data_sheet/SE98.pdf
+  * ON Semiconductor CAT34TS02, CAT6095
+    Prefix: 'cat34ts02', 'cat6095'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheet:
+       http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
+       http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
+  * ST Microelectronics STTS424, STTS424E02
+    Prefix: 'stts424'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+       http://www.st.com/stonline/products/literature/ds/13447/stts424.pdf
+       http://www.st.com/stonline/products/literature/ds/13448/stts424e02.pdf
+  * JEDEC JC 42.4 compliant temperature sensor chips
+    Prefix: 'jc42'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheet: -
+
+Author:
+       Guenter Roeck <guenter.roeck@ericsson.com>
+
+
+Description
+-----------
+
+This driver implements support for JEDEC JC 42.4 compliant temperature sensors.
+The driver auto-detects the chips listed above, but can be manually instantiated
+to support other JC 42.4 compliant chips.
+
+Example: the following will load the driver for a generic JC 42.4 compliant
+temperature sensor at address 0x18 on I2C bus #1:
+
+# modprobe jc42
+# echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device
+
+A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
+and critical temperature can be configured. There are alarms for high, low,
+and critical thresholds.
+
+There is also an hysteresis to control the thresholds for resetting alarms.
+Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
+3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
+limits. The chip supports only a single register to configure the hysteresis,
+which applies to all limits. This register can be written by writing into
+temp1_crit_hyst. Other hysteresis attributes are read-only.
+
+Sysfs entries
+-------------
+
+temp1_input            Temperature (RO)
+temp1_min              Minimum temperature (RW)
+temp1_max              Maximum temperature (RW)
+temp1_crit             Critical high temperature (RW)
+
+temp1_crit_hyst                Critical hysteresis temperature (RW)
+temp1_max_hyst         Maximum hysteresis temperature (RO)
+
+temp1_min_alarm                Temperature low alarm
+temp1_max_alarm                Temperature high alarm
+temp1_crit_alarm       Temperature critical alarm
index caacbcc..c8a0a39 100644 (file)
@@ -3211,6 +3211,13 @@ F:       Documentation/video4linux/*.ivtv
 F:     drivers/media/video/ivtv/
 F:     include/linux/ivtv*
 
+JC42.4 TEMPERATURE SENSOR DRIVER
+M:     Guenter Roeck <linux@roeck-us.net>
+L:     lm-sensors@lm-sensors.org
+S:     Maintained
+F:     drivers/hwmon/jc42.c
+F:     Documentation/hwmon/jc42
+
 JFS FILESYSTEM
 M:     Dave Kleikamp <shaggy@linux.vnet.ibm.com>
 L:     jfs-discussion@lists.sourceforge.net
index c80ba49..b0de75c 100644 (file)
@@ -463,6 +463,17 @@ config SENSORS_JZ4740
          This driver can also be build as a module. If so, the module will be
          called jz4740-hwmon.
 
+config SENSORS_JC42
+       tristate "JEDEC JC42.4 compliant temperature sensors"
+       help
+         If you say yes here you get support for Jedec JC42.4 compliant
+         temperature sensors. Support will include, but not be limited to,
+         ADT7408, CAT34TS02,, CAT6095, MAX6604, MCP9805, MCP98242, MCP98243,
+         MCP9843, SE97, SE98, STTS424, TSE2002B3, and TS3000B3.
+
+         This driver can also be built as a module.  If so, the module
+         will be called jc42.
+
 config SENSORS_LM63
        tristate "National Semiconductor LM63 and LM64"
        depends on I2C
index db24fa1..13d913e 100644 (file)
@@ -56,6 +56,7 @@ obj-$(CONFIG_SENSORS_I5K_AMB) += i5k_amb.o
 obj-$(CONFIG_SENSORS_IBMAEM)   += ibmaem.o
 obj-$(CONFIG_SENSORS_IBMPEX)   += ibmpex.o
 obj-$(CONFIG_SENSORS_IT87)     += it87.o
+obj-$(CONFIG_SENSORS_JC42)     += jc42.o
 obj-$(CONFIG_SENSORS_JZ4740)   += jz4740-hwmon.o
 obj-$(CONFIG_SENSORS_K8TEMP)   += k8temp.o
 obj-$(CONFIG_SENSORS_K10TEMP)  += k10temp.o
diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
new file mode 100644 (file)
index 0000000..340fc78
--- /dev/null
@@ -0,0 +1,593 @@
+/*
+ * jc42.c - driver for Jedec JC42.4 compliant temperature sensors
+ *
+ * Copyright (c) 2010  Ericsson AB.
+ *
+ * Derived from lm77.c by Andras BALI <drewie@freemail.hu>.
+ *
+ * JC42.4 compliant temperature sensors are typically used on memory modules.
+ *
+ * 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>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = {
+       0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, I2C_CLIENT_END };
+
+/* JC42 registers. All registers are 16 bit. */
+#define JC42_REG_CAP           0x00
+#define JC42_REG_CONFIG                0x01
+#define JC42_REG_TEMP_UPPER    0x02
+#define JC42_REG_TEMP_LOWER    0x03
+#define JC42_REG_TEMP_CRITICAL 0x04
+#define JC42_REG_TEMP          0x05
+#define JC42_REG_MANID         0x06
+#define JC42_REG_DEVICEID      0x07
+
+/* Status bits in temperature register */
+#define JC42_ALARM_CRIT_BIT    15
+#define JC42_ALARM_MAX_BIT     14
+#define JC42_ALARM_MIN_BIT     13
+
+/* Configuration register defines */
+#define JC42_CFG_CRIT_ONLY     (1 << 2)
+#define JC42_CFG_SHUTDOWN      (1 << 8)
+#define JC42_CFG_HYST_SHIFT    9
+#define JC42_CFG_HYST_MASK     0x03
+
+/* Capabilities */
+#define JC42_CAP_RANGE         (1 << 2)
+
+/* Manufacturer IDs */
+#define ADT_MANID              0x11d4  /* Analog Devices */
+#define MAX_MANID              0x004d  /* Maxim */
+#define IDT_MANID              0x00b3  /* IDT */
+#define MCP_MANID              0x0054  /* Microchip */
+#define NXP_MANID              0x1131  /* NXP Semiconductors */
+#define ONS_MANID              0x1b09  /* ON Semiconductor */
+#define STM_MANID              0x104a  /* ST Microelectronics */
+
+/* Supported chips */
+
+/* Analog Devices */
+#define ADT7408_DEVID          0x0801
+#define ADT7408_DEVID_MASK     0xffff
+
+/* IDT */
+#define TS3000B3_DEVID         0x2903  /* Also matches TSE2002B3 */
+#define TS3000B3_DEVID_MASK    0xffff
+
+/* Maxim */
+#define MAX6604_DEVID          0x3e00
+#define MAX6604_DEVID_MASK     0xffff
+
+/* Microchip */
+#define MCP98242_DEVID         0x2000
+#define MCP98242_DEVID_MASK    0xfffc
+
+#define MCP98243_DEVID         0x2100
+#define MCP98243_DEVID_MASK    0xfffc
+
+#define MCP9843_DEVID          0x0000  /* Also matches mcp9805 */
+#define MCP9843_DEVID_MASK     0xfffe
+
+/* NXP */
+#define SE97_DEVID             0xa200
+#define SE97_DEVID_MASK                0xfffc
+
+#define SE98_DEVID             0xa100
+#define SE98_DEVID_MASK                0xfffc
+
+/* ON Semiconductor */
+#define CAT6095_DEVID          0x0800  /* Also matches CAT34TS02 */
+#define CAT6095_DEVID_MASK     0xffe0
+
+/* ST Microelectronics */
+#define STTS424_DEVID          0x0101
+#define STTS424_DEVID_MASK     0xffff
+
+#define STTS424E_DEVID         0x0000
+#define STTS424E_DEVID_MASK    0xfffe
+
+static u16 jc42_hysteresis[] = { 0, 1500, 3000, 6000 };
+
+struct jc42_chips {
+       u16 manid;
+       u16 devid;
+       u16 devid_mask;
+};
+
+static struct jc42_chips jc42_chips[] = {
+       { ADT_MANID, ADT7408_DEVID, ADT7408_DEVID_MASK },
+       { IDT_MANID, TS3000B3_DEVID, TS3000B3_DEVID_MASK },
+       { MAX_MANID, MAX6604_DEVID, MAX6604_DEVID_MASK },
+       { MCP_MANID, MCP98242_DEVID, MCP98242_DEVID_MASK },
+       { MCP_MANID, MCP98243_DEVID, MCP98243_DEVID_MASK },
+       { MCP_MANID, MCP9843_DEVID, MCP9843_DEVID_MASK },
+       { NXP_MANID, SE97_DEVID, SE97_DEVID_MASK },
+       { ONS_MANID, CAT6095_DEVID, CAT6095_DEVID_MASK },
+       { NXP_MANID, SE98_DEVID, SE98_DEVID_MASK },
+       { STM_MANID, STTS424_DEVID, STTS424_DEVID_MASK },
+       { STM_MANID, STTS424E_DEVID, STTS424E_DEVID_MASK },
+};
+
+/* Each client has this additional data */
+struct jc42_data {
+       struct device   *hwmon_dev;
+       struct mutex    update_lock;    /* protect register access */
+       bool            extended;       /* true if extended range supported */
+       bool            valid;
+       unsigned long   last_updated;   /* In jiffies */
+       u16             orig_config;    /* original configuration */
+       u16             config;         /* current configuration */
+       u16             temp_input;     /* Temperatures */
+       u16             temp_crit;
+       u16             temp_min;
+       u16             temp_max;
+};
+
+static int jc42_probe(struct i2c_client *client,
+                     const struct i2c_device_id *id);
+static int jc42_detect(struct i2c_client *client, struct i2c_board_info *info);
+static int jc42_remove(struct i2c_client *client);
+static int jc42_read_value(struct i2c_client *client, u8 reg);
+static int jc42_write_value(struct i2c_client *client, u8 reg, u16 value);
+
+static struct jc42_data *jc42_update_device(struct device *dev);
+
+static const struct i2c_device_id jc42_id[] = {
+       { "adt7408", 0 },
+       { "cat94ts02", 0 },
+       { "cat6095", 0 },
+       { "jc42", 0 },
+       { "max6604", 0 },
+       { "mcp9805", 0 },
+       { "mcp98242", 0 },
+       { "mcp98243", 0 },
+       { "mcp9843", 0 },
+       { "se97", 0 },
+       { "se97b", 0 },
+       { "se98", 0 },
+       { "stts424", 0 },
+       { "tse2002b3", 0 },
+       { "ts3000b3", 0 },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, jc42_id);
+
+#ifdef CONFIG_PM
+
+static int jc42_suspend(struct device *dev)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct jc42_data *data = i2c_get_clientdata(client);
+
+       data->config |= JC42_CFG_SHUTDOWN;
+       jc42_write_value(client, JC42_REG_CONFIG, data->config);
+       return 0;
+}
+
+static int jc42_resume(struct device *dev)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct jc42_data *data = i2c_get_clientdata(client);
+
+       data->config &= ~JC42_CFG_SHUTDOWN;
+       jc42_write_value(client, JC42_REG_CONFIG, data->config);
+       return 0;
+}
+
+static const struct dev_pm_ops jc42_dev_pm_ops = {
+       .suspend = jc42_suspend,
+       .resume = jc42_resume,
+};
+
+#define JC42_DEV_PM_OPS (&jc42_dev_pm_ops)
+#else
+#define JC42_DEV_PM_OPS NULL
+#endif /* CONFIG_PM */
+
+/* This is the driver that will be inserted */
+static struct i2c_driver jc42_driver = {
+       .class          = I2C_CLASS_HWMON,
+       .driver = {
+               .name   = "jc42",
+               .pm = JC42_DEV_PM_OPS,
+       },
+       .probe          = jc42_probe,
+       .remove         = jc42_remove,
+       .id_table       = jc42_id,
+       .detect         = jc42_detect,
+       .address_list   = normal_i2c,
+};
+
+#define JC42_TEMP_MIN_EXTENDED (-40000)
+#define JC42_TEMP_MIN          0
+#define JC42_TEMP_MAX          125000
+
+static u16 jc42_temp_to_reg(int temp, bool extended)
+{
+       int ntemp = SENSORS_LIMIT(temp,
+                                 extended ? JC42_TEMP_MIN_EXTENDED :
+                                 JC42_TEMP_MIN, JC42_TEMP_MAX);
+
+       /* convert from 0.001 to 0.0625 resolution */
+       return (ntemp * 2 / 125) & 0x1fff;
+}
+
+static int jc42_temp_from_reg(s16 reg)
+{
+       reg &= 0x1fff;
+
+       /* sign extend register */
+       if (reg & 0x1000)
+               reg |= 0xf000;
+
+       /* convert from 0.0625 to 0.001 resolution */
+       return reg * 125 / 2;
+}
+
+/* sysfs stuff */
+
+/* read routines for temperature limits */
+#define show(value)    \
+static ssize_t show_##value(struct device *dev,                                \
+                           struct device_attribute *attr,              \
+                           char *buf)                                  \
+{                                                                      \
+       struct jc42_data *data = jc42_update_device(dev);               \
+       if (IS_ERR(data))                                               \
+               return PTR_ERR(data);                                   \
+       return sprintf(buf, "%d\n", jc42_temp_from_reg(data->value));   \
+}
+
+show(temp_input);
+show(temp_crit);
+show(temp_min);
+show(temp_max);
+
+/* read routines for hysteresis values */
+static ssize_t show_temp_crit_hyst(struct device *dev,
+                                  struct device_attribute *attr, char *buf)
+{
+       struct jc42_data *data = jc42_update_device(dev);
+       int temp, hyst;
+
+       if (IS_ERR(data))
+               return PTR_ERR(data);
+
+       temp = jc42_temp_from_reg(data->temp_crit);
+       hyst = jc42_hysteresis[(data->config >> JC42_CFG_HYST_SHIFT)
+                              & JC42_CFG_HYST_MASK];
+       return sprintf(buf, "%d\n", temp - hyst);
+}
+
+static ssize_t show_temp_max_hyst(struct device *dev,
+                                 struct device_attribute *attr, char *buf)
+{
+       struct jc42_data *data = jc42_update_device(dev);
+       int temp, hyst;
+
+       if (IS_ERR(data))
+               return PTR_ERR(data);
+
+       temp = jc42_temp_from_reg(data->temp_max);
+       hyst = jc42_hysteresis[(data->config >> JC42_CFG_HYST_SHIFT)
+                              & JC42_CFG_HYST_MASK];
+       return sprintf(buf, "%d\n", temp - hyst);
+}
+
+/* write routines */
+#define set(value, reg)        \
+static ssize_t set_##value(struct device *dev,                         \
+                          struct device_attribute *attr,               \
+                          const char *buf, size_t count)               \
+{                                                                      \
+       struct i2c_client *client = to_i2c_client(dev);                 \
+       struct jc42_data *data = i2c_get_clientdata(client);            \
+       int err, ret = count;                                           \
+       long val;                                                       \
+       if (strict_strtol(buf, 10, &val) < 0)                           \
+               return -EINVAL;                                         \
+       mutex_lock(&data->update_lock);                                 \
+       data->value = jc42_temp_to_reg(val, data->extended);            \
+       err = jc42_write_value(client, reg, data->value);               \
+       if (err < 0)                                                    \
+               ret = err;                                              \
+       mutex_unlock(&data->update_lock);                               \
+       return ret;                                                     \
+}
+
+set(temp_min, JC42_REG_TEMP_LOWER);
+set(temp_max, JC42_REG_TEMP_UPPER);
+set(temp_crit, JC42_REG_TEMP_CRITICAL);
+
+/* JC42.4 compliant chips only support four hysteresis values.
+ * Pick best choice and go from there. */
+static ssize_t set_temp_crit_hyst(struct device *dev,
+                                 struct device_attribute *attr,
+                                 const char *buf, size_t count)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct jc42_data *data = i2c_get_clientdata(client);
+       long val;
+       int diff, hyst;
+       int err;
+       int ret = count;
+
+       if (strict_strtoul(buf, 10, &val) < 0)
+               return -EINVAL;
+
+       diff = jc42_temp_from_reg(data->temp_crit) - val;
+       hyst = 0;
+       if (diff > 0) {
+               if (diff < 2250)
+                       hyst = 1;       /* 1.5 degrees C */
+               else if (diff < 4500)
+                       hyst = 2;       /* 3.0 degrees C */
+               else
+                       hyst = 3;       /* 6.0 degrees C */
+       }
+
+       mutex_lock(&data->update_lock);
+       data->config = (data->config
+                       & ~(JC42_CFG_HYST_MASK << JC42_CFG_HYST_SHIFT))
+         | (hyst << JC42_CFG_HYST_SHIFT);
+       err = jc42_write_value(client, JC42_REG_CONFIG, data->config);
+       if (err < 0)
+               ret = err;
+       mutex_unlock(&data->update_lock);
+       return ret;
+}
+
+static ssize_t show_alarm(struct device *dev,
+                         struct device_attribute *attr, char *buf)
+{
+       u16 bit = to_sensor_dev_attr(attr)->index;
+       struct jc42_data *data = jc42_update_device(dev);
+       u16 val;
+
+       if (IS_ERR(data))
+               return PTR_ERR(data);
+
+       val = data->temp_input;
+       if (bit != JC42_ALARM_CRIT_BIT && (data->config & JC42_CFG_CRIT_ONLY))
+               val = 0;
+       return sprintf(buf, "%u\n", (val >> bit) & 1);
+}
+
+static DEVICE_ATTR(temp1_input, S_IRUGO,
+                  show_temp_input, NULL);
+static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
+                  show_temp_crit, set_temp_crit);
+static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
+                  show_temp_min, set_temp_min);
+static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
+                  show_temp_max, set_temp_max);
+
+static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
+                  show_temp_crit_hyst, set_temp_crit_hyst);
+static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
+                  show_temp_max_hyst, NULL);
+
+static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
+                         JC42_ALARM_CRIT_BIT);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
+                         JC42_ALARM_MIN_BIT);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
+                         JC42_ALARM_MAX_BIT);
+
+static struct attribute *jc42_attributes[] = {
+       &dev_attr_temp1_input.attr,
+       &dev_attr_temp1_crit.attr,
+       &dev_attr_temp1_min.attr,
+       &dev_attr_temp1_max.attr,
+       &dev_attr_temp1_crit_hyst.attr,
+       &dev_attr_temp1_max_hyst.attr,
+       &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
+       &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+       &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+       NULL
+};
+
+static const struct attribute_group jc42_group = {
+       .attrs = jc42_attributes,
+};
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int jc42_detect(struct i2c_client *new_client,
+                      struct i2c_board_info *info)
+{
+       struct i2c_adapter *adapter = new_client->adapter;
+       int i, config, cap, manid, devid;
+
+       if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+                                    I2C_FUNC_SMBUS_WORD_DATA))
+               return -ENODEV;
+
+       cap = jc42_read_value(new_client, JC42_REG_CAP);
+       config = jc42_read_value(new_client, JC42_REG_CONFIG);
+       manid = jc42_read_value(new_client, JC42_REG_MANID);
+       devid = jc42_read_value(new_client, JC42_REG_DEVICEID);
+
+       if (cap < 0 || config < 0 || manid < 0 || devid < 0)
+               return -ENODEV;
+
+       if ((cap & 0xff00) || (config & 0xf800))
+               return -ENODEV;
+
+       for (i = 0; i < ARRAY_SIZE(jc42_chips); i++) {
+               struct jc42_chips *chip = &jc42_chips[i];
+               if (manid == chip->manid &&
+                   (devid & chip->devid_mask) == chip->devid) {
+                       strlcpy(info->type, "jc42", I2C_NAME_SIZE);
+                       return 0;
+               }
+       }
+       return -ENODEV;
+}
+
+static int jc42_probe(struct i2c_client *new_client,
+                     const struct i2c_device_id *id)
+{
+       struct jc42_data *data;
+       int config, cap, err;
+
+       data = kzalloc(sizeof(struct jc42_data), GFP_KERNEL);
+       if (!data) {
+               err = -ENOMEM;
+               goto exit;
+       }
+
+       i2c_set_clientdata(new_client, data);
+       mutex_init(&data->update_lock);
+
+       cap = jc42_read_value(new_client, JC42_REG_CAP);
+       if (cap < 0) {
+               err = -EINVAL;
+               goto exit_free;
+       }
+       data->extended = !!(cap & JC42_CAP_RANGE);
+
+       config = jc42_read_value(new_client, JC42_REG_CONFIG);
+       if (config < 0) {
+               err = -EINVAL;
+               goto exit_free;
+       }
+       data->orig_config = config;
+       if (config & JC42_CFG_SHUTDOWN) {
+               config &= ~JC42_CFG_SHUTDOWN;
+               jc42_write_value(new_client, JC42_REG_CONFIG, config);
+       }
+       data->config = config;
+
+       /* Register sysfs hooks */
+       err = sysfs_create_group(&new_client->dev.kobj, &jc42_group);
+       if (err)
+               goto exit_free;
+
+       data->hwmon_dev = hwmon_device_register(&new_client->dev);
+       if (IS_ERR(data->hwmon_dev)) {
+               err = PTR_ERR(data->hwmon_dev);
+               goto exit_remove;
+       }
+
+       return 0;
+
+exit_remove:
+       sysfs_remove_group(&new_client->dev.kobj, &jc42_group);
+exit_free:
+       kfree(data);
+exit:
+       return err;
+}
+
+static int jc42_remove(struct i2c_client *client)
+{
+       struct jc42_data *data = i2c_get_clientdata(client);
+       hwmon_device_unregister(data->hwmon_dev);
+       sysfs_remove_group(&client->dev.kobj, &jc42_group);
+       if (data->config != data->orig_config)
+               jc42_write_value(client, JC42_REG_CONFIG, data->orig_config);
+       kfree(data);
+       return 0;
+}
+
+/* All registers are word-sized. */
+static int jc42_read_value(struct i2c_client *client, u8 reg)
+{
+       int ret = i2c_smbus_read_word_data(client, reg);
+       if (ret < 0)
+               return ret;
+       return swab16(ret);
+}
+
+static int jc42_write_value(struct i2c_client *client, u8 reg, u16 value)
+{
+       return i2c_smbus_write_word_data(client, reg, swab16(value));
+}
+
+static struct jc42_data *jc42_update_device(struct device *dev)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct jc42_data *data = i2c_get_clientdata(client);
+       struct jc42_data *ret = data;
+       int val;
+
+       mutex_lock(&data->update_lock);
+
+       if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+               val = jc42_read_value(client, JC42_REG_TEMP);
+               if (val < 0) {
+                       ret = ERR_PTR(val);
+                       goto abort;
+               }
+               data->temp_input = val;
+
+               val = jc42_read_value(client, JC42_REG_TEMP_CRITICAL);
+               if (val < 0) {
+                       ret = ERR_PTR(val);
+                       goto abort;
+               }
+               data->temp_crit = val;
+
+               val = jc42_read_value(client, JC42_REG_TEMP_LOWER);
+               if (val < 0) {
+                       ret = ERR_PTR(val);
+                       goto abort;
+               }
+               data->temp_min = val;
+
+               val = jc42_read_value(client, JC42_REG_TEMP_UPPER);
+               if (val < 0) {
+                       ret = ERR_PTR(val);
+                       goto abort;
+               }
+               data->temp_max = val;
+
+               data->last_updated = jiffies;
+               data->valid = true;
+       }
+abort:
+       mutex_unlock(&data->update_lock);
+       return ret;
+}
+
+static int __init sensors_jc42_init(void)
+{
+       return i2c_add_driver(&jc42_driver);
+}
+
+static void __exit sensors_jc42_exit(void)
+{
+       i2c_del_driver(&jc42_driver);
+}
+
+MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
+MODULE_DESCRIPTION("JC42 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sensors_jc42_init);
+module_exit(sensors_jc42_exit);