Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / hwmon / emc2103.c
diff --git a/kernel/drivers/hwmon/emc2103.c b/kernel/drivers/hwmon/emc2103.c
new file mode 100644 (file)
index 0000000..952fe69
--- /dev/null
@@ -0,0 +1,693 @@
+/*
+ * emc2103.c - Support for SMSC EMC2103
+ * Copyright (c) 2010 SMSC
+ *
+ * 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 scanned */
+static const unsigned short normal_i2c[] = { 0x2E, I2C_CLIENT_END };
+
+static const u8 REG_TEMP[4] = { 0x00, 0x02, 0x04, 0x06 };
+static const u8 REG_TEMP_MIN[4] = { 0x3c, 0x38, 0x39, 0x3a };
+static const u8 REG_TEMP_MAX[4] = { 0x34, 0x30, 0x31, 0x32 };
+
+#define REG_CONF1              0x20
+#define REG_TEMP_MAX_ALARM     0x24
+#define REG_TEMP_MIN_ALARM     0x25
+#define REG_FAN_CONF1          0x42
+#define REG_FAN_TARGET_LO      0x4c
+#define REG_FAN_TARGET_HI      0x4d
+#define REG_FAN_TACH_HI                0x4e
+#define REG_FAN_TACH_LO                0x4f
+#define REG_PRODUCT_ID         0xfd
+#define REG_MFG_ID             0xfe
+
+/* equation 4 from datasheet: rpm = (3932160 * multipler) / count */
+#define FAN_RPM_FACTOR         3932160
+
+/*
+ * 2103-2 and 2103-4's 3rd temperature sensor can be connected to two diodes
+ * in anti-parallel mode, and in this configuration both can be read
+ * independently (so we have 4 temperature inputs).  The device can't
+ * detect if it's connected in this mode, so we have to manually enable
+ * it.  Default is to leave the device in the state it's already in (-1).
+ * This parameter allows APD mode to be optionally forced on or off
+ */
+static int apd = -1;
+module_param(apd, bint, 0);
+MODULE_PARM_DESC(init, "Set to zero to disable anti-parallel diode mode");
+
+struct temperature {
+       s8      degrees;
+       u8      fraction;       /* 0-7 multiples of 0.125 */
+};
+
+struct emc2103_data {
+       struct i2c_client       *client;
+       const struct            attribute_group *groups[4];
+       struct mutex            update_lock;
+       bool                    valid;          /* registers are valid */
+       bool                    fan_rpm_control;
+       int                     temp_count;     /* num of temp sensors */
+       unsigned long           last_updated;   /* in jiffies */
+       struct temperature      temp[4];        /* internal + 3 external */
+       s8                      temp_min[4];    /* no fractional part */
+       s8                      temp_max[4];    /* no fractional part */
+       u8                      temp_min_alarm;
+       u8                      temp_max_alarm;
+       u8                      fan_multiplier;
+       u16                     fan_tach;
+       u16                     fan_target;
+};
+
+static int read_u8_from_i2c(struct i2c_client *client, u8 i2c_reg, u8 *output)
+{
+       int status = i2c_smbus_read_byte_data(client, i2c_reg);
+       if (status < 0) {
+               dev_warn(&client->dev, "reg 0x%02x, err %d\n",
+                       i2c_reg, status);
+       } else {
+               *output = status;
+       }
+       return status;
+}
+
+static void read_temp_from_i2c(struct i2c_client *client, u8 i2c_reg,
+                              struct temperature *temp)
+{
+       u8 degrees, fractional;
+
+       if (read_u8_from_i2c(client, i2c_reg, &degrees) < 0)
+               return;
+
+       if (read_u8_from_i2c(client, i2c_reg + 1, &fractional) < 0)
+               return;
+
+       temp->degrees = degrees;
+       temp->fraction = (fractional & 0xe0) >> 5;
+}
+
+static void read_fan_from_i2c(struct i2c_client *client, u16 *output,
+                             u8 hi_addr, u8 lo_addr)
+{
+       u8 high_byte, lo_byte;
+
+       if (read_u8_from_i2c(client, hi_addr, &high_byte) < 0)
+               return;
+
+       if (read_u8_from_i2c(client, lo_addr, &lo_byte) < 0)
+               return;
+
+       *output = ((u16)high_byte << 5) | (lo_byte >> 3);
+}
+
+static void write_fan_target_to_i2c(struct i2c_client *client, u16 new_target)
+{
+       u8 high_byte = (new_target & 0x1fe0) >> 5;
+       u8 low_byte = (new_target & 0x001f) << 3;
+       i2c_smbus_write_byte_data(client, REG_FAN_TARGET_LO, low_byte);
+       i2c_smbus_write_byte_data(client, REG_FAN_TARGET_HI, high_byte);
+}
+
+static void read_fan_config_from_i2c(struct i2c_client *client)
+
+{
+       struct emc2103_data *data = i2c_get_clientdata(client);
+       u8 conf1;
+
+       if (read_u8_from_i2c(client, REG_FAN_CONF1, &conf1) < 0)
+               return;
+
+       data->fan_multiplier = 1 << ((conf1 & 0x60) >> 5);
+       data->fan_rpm_control = (conf1 & 0x80) != 0;
+}
+
+static struct emc2103_data *emc2103_update_device(struct device *dev)
+{
+       struct emc2103_data *data = dev_get_drvdata(dev);
+       struct i2c_client *client = data->client;
+
+       mutex_lock(&data->update_lock);
+
+       if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+           || !data->valid) {
+               int i;
+
+               for (i = 0; i < data->temp_count; i++) {
+                       read_temp_from_i2c(client, REG_TEMP[i], &data->temp[i]);
+                       read_u8_from_i2c(client, REG_TEMP_MIN[i],
+                               &data->temp_min[i]);
+                       read_u8_from_i2c(client, REG_TEMP_MAX[i],
+                               &data->temp_max[i]);
+               }
+
+               read_u8_from_i2c(client, REG_TEMP_MIN_ALARM,
+                       &data->temp_min_alarm);
+               read_u8_from_i2c(client, REG_TEMP_MAX_ALARM,
+                       &data->temp_max_alarm);
+
+               read_fan_from_i2c(client, &data->fan_tach,
+                       REG_FAN_TACH_HI, REG_FAN_TACH_LO);
+               read_fan_from_i2c(client, &data->fan_target,
+                       REG_FAN_TARGET_HI, REG_FAN_TARGET_LO);
+               read_fan_config_from_i2c(client);
+
+               data->last_updated = jiffies;
+               data->valid = true;
+       }
+
+       mutex_unlock(&data->update_lock);
+
+       return data;
+}
+
+static ssize_t
+show_temp(struct device *dev, struct device_attribute *da, char *buf)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = emc2103_update_device(dev);
+       int millidegrees = data->temp[nr].degrees * 1000
+               + data->temp[nr].fraction * 125;
+       return sprintf(buf, "%d\n", millidegrees);
+}
+
+static ssize_t
+show_temp_min(struct device *dev, struct device_attribute *da, char *buf)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = emc2103_update_device(dev);
+       int millidegrees = data->temp_min[nr] * 1000;
+       return sprintf(buf, "%d\n", millidegrees);
+}
+
+static ssize_t
+show_temp_max(struct device *dev, struct device_attribute *da, char *buf)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = emc2103_update_device(dev);
+       int millidegrees = data->temp_max[nr] * 1000;
+       return sprintf(buf, "%d\n", millidegrees);
+}
+
+static ssize_t
+show_temp_fault(struct device *dev, struct device_attribute *da, char *buf)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = emc2103_update_device(dev);
+       bool fault = (data->temp[nr].degrees == -128);
+       return sprintf(buf, "%d\n", fault ? 1 : 0);
+}
+
+static ssize_t
+show_temp_min_alarm(struct device *dev, struct device_attribute *da, char *buf)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = emc2103_update_device(dev);
+       bool alarm = data->temp_min_alarm & (1 << nr);
+       return sprintf(buf, "%d\n", alarm ? 1 : 0);
+}
+
+static ssize_t
+show_temp_max_alarm(struct device *dev, struct device_attribute *da, char *buf)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = emc2103_update_device(dev);
+       bool alarm = data->temp_max_alarm & (1 << nr);
+       return sprintf(buf, "%d\n", alarm ? 1 : 0);
+}
+
+static ssize_t set_temp_min(struct device *dev, struct device_attribute *da,
+                           const char *buf, size_t count)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = dev_get_drvdata(dev);
+       struct i2c_client *client = data->client;
+       long val;
+
+       int result = kstrtol(buf, 10, &val);
+       if (result < 0)
+               return result;
+
+       val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), -63, 127);
+
+       mutex_lock(&data->update_lock);
+       data->temp_min[nr] = val;
+       i2c_smbus_write_byte_data(client, REG_TEMP_MIN[nr], val);
+       mutex_unlock(&data->update_lock);
+
+       return count;
+}
+
+static ssize_t set_temp_max(struct device *dev, struct device_attribute *da,
+                           const char *buf, size_t count)
+{
+       int nr = to_sensor_dev_attr(da)->index;
+       struct emc2103_data *data = dev_get_drvdata(dev);
+       struct i2c_client *client = data->client;
+       long val;
+
+       int result = kstrtol(buf, 10, &val);
+       if (result < 0)
+               return result;
+
+       val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), -63, 127);
+
+       mutex_lock(&data->update_lock);
+       data->temp_max[nr] = val;
+       i2c_smbus_write_byte_data(client, REG_TEMP_MAX[nr], val);
+       mutex_unlock(&data->update_lock);
+
+       return count;
+}
+
+static ssize_t
+show_fan(struct device *dev, struct device_attribute *da, char *buf)
+{
+       struct emc2103_data *data = emc2103_update_device(dev);
+       int rpm = 0;
+       if (data->fan_tach != 0)
+               rpm = (FAN_RPM_FACTOR * data->fan_multiplier) / data->fan_tach;
+       return sprintf(buf, "%d\n", rpm);
+}
+
+static ssize_t
+show_fan_div(struct device *dev, struct device_attribute *da, char *buf)
+{
+       struct emc2103_data *data = emc2103_update_device(dev);
+       int fan_div = 8 / data->fan_multiplier;
+       return sprintf(buf, "%d\n", fan_div);
+}
+
+/*
+ * Note: we also update the fan target here, because its value is
+ * determined in part by the fan clock divider.  This follows the principle
+ * of least surprise; the user doesn't expect the fan target to change just
+ * because the divider changed.
+ */
+static ssize_t set_fan_div(struct device *dev, struct device_attribute *da,
+                          const char *buf, size_t count)
+{
+       struct emc2103_data *data = emc2103_update_device(dev);
+       struct i2c_client *client = data->client;
+       int new_range_bits, old_div = 8 / data->fan_multiplier;
+       long new_div;
+
+       int status = kstrtol(buf, 10, &new_div);
+       if (status < 0)
+               return status;
+
+       if (new_div == old_div) /* No change */
+               return count;
+
+       switch (new_div) {
+       case 1:
+               new_range_bits = 3;
+               break;
+       case 2:
+               new_range_bits = 2;
+               break;
+       case 4:
+               new_range_bits = 1;
+               break;
+       case 8:
+               new_range_bits = 0;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       mutex_lock(&data->update_lock);
+
+       status = i2c_smbus_read_byte_data(client, REG_FAN_CONF1);
+       if (status < 0) {
+               dev_dbg(&client->dev, "reg 0x%02x, err %d\n",
+                       REG_FAN_CONF1, status);
+               mutex_unlock(&data->update_lock);
+               return status;
+       }
+       status &= 0x9F;
+       status |= (new_range_bits << 5);
+       i2c_smbus_write_byte_data(client, REG_FAN_CONF1, status);
+
+       data->fan_multiplier = 8 / new_div;
+
+       /* update fan target if high byte is not disabled */
+       if ((data->fan_target & 0x1fe0) != 0x1fe0) {
+               u16 new_target = (data->fan_target * old_div) / new_div;
+               data->fan_target = min(new_target, (u16)0x1fff);
+               write_fan_target_to_i2c(client, data->fan_target);
+       }
+
+       /* invalidate data to force re-read from hardware */
+       data->valid = false;
+
+       mutex_unlock(&data->update_lock);
+       return count;
+}
+
+static ssize_t
+show_fan_target(struct device *dev, struct device_attribute *da, char *buf)
+{
+       struct emc2103_data *data = emc2103_update_device(dev);
+       int rpm = 0;
+
+       /* high byte of 0xff indicates disabled so return 0 */
+       if ((data->fan_target != 0) && ((data->fan_target & 0x1fe0) != 0x1fe0))
+               rpm = (FAN_RPM_FACTOR * data->fan_multiplier)
+                       / data->fan_target;
+
+       return sprintf(buf, "%d\n", rpm);
+}
+
+static ssize_t set_fan_target(struct device *dev, struct device_attribute *da,
+                             const char *buf, size_t count)
+{
+       struct emc2103_data *data = emc2103_update_device(dev);
+       struct i2c_client *client = data->client;
+       unsigned long rpm_target;
+
+       int result = kstrtoul(buf, 10, &rpm_target);
+       if (result < 0)
+               return result;
+
+       /* Datasheet states 16384 as maximum RPM target (table 3.2) */
+       rpm_target = clamp_val(rpm_target, 0, 16384);
+
+       mutex_lock(&data->update_lock);
+
+       if (rpm_target == 0)
+               data->fan_target = 0x1fff;
+       else
+               data->fan_target = clamp_val(
+                       (FAN_RPM_FACTOR * data->fan_multiplier) / rpm_target,
+                       0, 0x1fff);
+
+       write_fan_target_to_i2c(client, data->fan_target);
+
+       mutex_unlock(&data->update_lock);
+       return count;
+}
+
+static ssize_t
+show_fan_fault(struct device *dev, struct device_attribute *da, char *buf)
+{
+       struct emc2103_data *data = emc2103_update_device(dev);
+       bool fault = ((data->fan_tach & 0x1fe0) == 0x1fe0);
+       return sprintf(buf, "%d\n", fault ? 1 : 0);
+}
+
+static ssize_t
+show_pwm_enable(struct device *dev, struct device_attribute *da, char *buf)
+{
+       struct emc2103_data *data = emc2103_update_device(dev);
+       return sprintf(buf, "%d\n", data->fan_rpm_control ? 3 : 0);
+}
+
+static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *da,
+                             const char *buf, size_t count)
+{
+       struct emc2103_data *data = dev_get_drvdata(dev);
+       struct i2c_client *client = data->client;
+       long new_value;
+       u8 conf_reg;
+
+       int result = kstrtol(buf, 10, &new_value);
+       if (result < 0)
+               return result;
+
+       mutex_lock(&data->update_lock);
+       switch (new_value) {
+       case 0:
+               data->fan_rpm_control = false;
+               break;
+       case 3:
+               data->fan_rpm_control = true;
+               break;
+       default:
+               count = -EINVAL;
+               goto err;
+       }
+
+       result = read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg);
+       if (result) {
+               count = result;
+               goto err;
+       }
+
+       if (data->fan_rpm_control)
+               conf_reg |= 0x80;
+       else
+               conf_reg &= ~0x80;
+
+       i2c_smbus_write_byte_data(client, REG_FAN_CONF1, conf_reg);
+err:
+       mutex_unlock(&data->update_lock);
+       return count;
+}
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO | S_IWUSR, show_temp_min,
+       set_temp_min, 0);
+static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO | S_IWUSR, show_temp_max,
+       set_temp_max, 0);
+static SENSOR_DEVICE_ATTR(temp1_fault, S_IRUGO, show_temp_fault, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_temp_min_alarm,
+       NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_temp_max_alarm,
+       NULL, 0);
+
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO | S_IWUSR, show_temp_min,
+       set_temp_min, 1);
+static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO | S_IWUSR, show_temp_max,
+       set_temp_max, 1);
+static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_temp_fault, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_temp_min_alarm,
+       NULL, 1);
+static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_temp_max_alarm,
+       NULL, 1);
+
+static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_min, S_IRUGO | S_IWUSR, show_temp_min,
+       set_temp_min, 2);
+static SENSOR_DEVICE_ATTR(temp3_max, S_IRUGO | S_IWUSR, show_temp_max,
+       set_temp_max, 2);
+static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_temp_fault, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_temp_min_alarm,
+       NULL, 2);
+static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_temp_max_alarm,
+       NULL, 2);
+
+static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_min, S_IRUGO | S_IWUSR, show_temp_min,
+       set_temp_min, 3);
+static SENSOR_DEVICE_ATTR(temp4_max, S_IRUGO | S_IWUSR, show_temp_max,
+       set_temp_max, 3);
+static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_temp_fault, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_min_alarm, S_IRUGO, show_temp_min_alarm,
+       NULL, 3);
+static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_temp_max_alarm,
+       NULL, 3);
+
+static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
+static DEVICE_ATTR(fan1_div, S_IRUGO | S_IWUSR, show_fan_div, set_fan_div);
+static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_fan_target,
+       set_fan_target);
+static DEVICE_ATTR(fan1_fault, S_IRUGO, show_fan_fault, NULL);
+
+static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR, show_pwm_enable,
+       set_pwm_enable);
+
+/* sensors present on all models */
+static struct attribute *emc2103_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_fault.dev_attr.attr,
+       &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+       &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+       &sensor_dev_attr_temp2_input.dev_attr.attr,
+       &sensor_dev_attr_temp2_min.dev_attr.attr,
+       &sensor_dev_attr_temp2_max.dev_attr.attr,
+       &sensor_dev_attr_temp2_fault.dev_attr.attr,
+       &sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
+       &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
+       &dev_attr_fan1_input.attr,
+       &dev_attr_fan1_div.attr,
+       &dev_attr_fan1_target.attr,
+       &dev_attr_fan1_fault.attr,
+       &dev_attr_pwm1_enable.attr,
+       NULL
+};
+
+/* extra temperature sensors only present on 2103-2 and 2103-4 */
+static struct attribute *emc2103_attributes_temp3[] = {
+       &sensor_dev_attr_temp3_input.dev_attr.attr,
+       &sensor_dev_attr_temp3_min.dev_attr.attr,
+       &sensor_dev_attr_temp3_max.dev_attr.attr,
+       &sensor_dev_attr_temp3_fault.dev_attr.attr,
+       &sensor_dev_attr_temp3_min_alarm.dev_attr.attr,
+       &sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
+       NULL
+};
+
+/* extra temperature sensors only present on 2103-2 and 2103-4 in APD mode */
+static struct attribute *emc2103_attributes_temp4[] = {
+       &sensor_dev_attr_temp4_input.dev_attr.attr,
+       &sensor_dev_attr_temp4_min.dev_attr.attr,
+       &sensor_dev_attr_temp4_max.dev_attr.attr,
+       &sensor_dev_attr_temp4_fault.dev_attr.attr,
+       &sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
+       &sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
+       NULL
+};
+
+static const struct attribute_group emc2103_group = {
+       .attrs = emc2103_attributes,
+};
+
+static const struct attribute_group emc2103_temp3_group = {
+       .attrs = emc2103_attributes_temp3,
+};
+
+static const struct attribute_group emc2103_temp4_group = {
+       .attrs = emc2103_attributes_temp4,
+};
+
+static int
+emc2103_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+       struct emc2103_data *data;
+       struct device *hwmon_dev;
+       int status, idx = 0;
+
+       if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+               return -EIO;
+
+       data = devm_kzalloc(&client->dev, sizeof(struct emc2103_data),
+                           GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       i2c_set_clientdata(client, data);
+       data->client = client;
+       mutex_init(&data->update_lock);
+
+       /* 2103-2 and 2103-4 have 3 external diodes, 2103-1 has 1 */
+       status = i2c_smbus_read_byte_data(client, REG_PRODUCT_ID);
+       if (status == 0x24) {
+               /* 2103-1 only has 1 external diode */
+               data->temp_count = 2;
+       } else {
+               /* 2103-2 and 2103-4 have 3 or 4 external diodes */
+               status = i2c_smbus_read_byte_data(client, REG_CONF1);
+               if (status < 0) {
+                       dev_dbg(&client->dev, "reg 0x%02x, err %d\n", REG_CONF1,
+                               status);
+                       return status;
+               }
+
+               /* detect current state of hardware */
+               data->temp_count = (status & 0x01) ? 4 : 3;
+
+               /* force APD state if module parameter is set */
+               if (apd == 0) {
+                       /* force APD mode off */
+                       data->temp_count = 3;
+                       status &= ~(0x01);
+                       i2c_smbus_write_byte_data(client, REG_CONF1, status);
+               } else if (apd == 1) {
+                       /* force APD mode on */
+                       data->temp_count = 4;
+                       status |= 0x01;
+                       i2c_smbus_write_byte_data(client, REG_CONF1, status);
+               }
+       }
+
+       /* sysfs hooks */
+       data->groups[idx++] = &emc2103_group;
+       if (data->temp_count >= 3)
+               data->groups[idx++] = &emc2103_temp3_group;
+       if (data->temp_count == 4)
+               data->groups[idx++] = &emc2103_temp4_group;
+
+       hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
+                                                          client->name, data,
+                                                          data->groups);
+       if (IS_ERR(hwmon_dev))
+               return PTR_ERR(hwmon_dev);
+
+       dev_info(&client->dev, "%s: sensor '%s'\n",
+                dev_name(hwmon_dev), client->name);
+
+       return 0;
+}
+
+static const struct i2c_device_id emc2103_ids[] = {
+       { "emc2103", 0, },
+       { /* LIST END */ }
+};
+MODULE_DEVICE_TABLE(i2c, emc2103_ids);
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int
+emc2103_detect(struct i2c_client *new_client, struct i2c_board_info *info)
+{
+       struct i2c_adapter *adapter = new_client->adapter;
+       int manufacturer, product;
+
+       if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+               return -ENODEV;
+
+       manufacturer = i2c_smbus_read_byte_data(new_client, REG_MFG_ID);
+       if (manufacturer != 0x5D)
+               return -ENODEV;
+
+       product = i2c_smbus_read_byte_data(new_client, REG_PRODUCT_ID);
+       if ((product != 0x24) && (product != 0x26))
+               return -ENODEV;
+
+       strlcpy(info->type, "emc2103", I2C_NAME_SIZE);
+
+       return 0;
+}
+
+static struct i2c_driver emc2103_driver = {
+       .class          = I2C_CLASS_HWMON,
+       .driver = {
+               .name   = "emc2103",
+       },
+       .probe          = emc2103_probe,
+       .id_table       = emc2103_ids,
+       .detect         = emc2103_detect,
+       .address_list   = normal_i2c,
+};
+
+module_i2c_driver(emc2103_driver);
+
+MODULE_AUTHOR("Steve Glendinning <steve.glendinning@shawell.net>");
+MODULE_DESCRIPTION("SMSC EMC2103 hwmon driver");
+MODULE_LICENSE("GPL");