--- /dev/null
+/*
+ * lm92 - Hardware monitoring driver
+ * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
+ *
+ * Based on the lm90 driver, with some ideas taken from the lm_sensors
+ * lm92 driver as well.
+ *
+ * The LM92 is a sensor chip made by National Semiconductor. It reports
+ * its own temperature with a 0.0625 deg resolution and a 0.33 deg
+ * accuracy. Complete datasheet can be obtained from National's website
+ * at:
+ * http://www.national.com/pf/LM/LM92.html
+ *
+ * This driver also supports the MAX6635 sensor chip made by Maxim.
+ * This chip is compatible with the LM92, but has a lesser accuracy
+ * (1.0 deg). Complete datasheet can be obtained from Maxim's website
+ * at:
+ * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
+ *
+ * Since the LM92 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.
+ *
+ * Support could easily be added for the National Semiconductor LM76
+ * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
+ * with the LM92.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/jiffies.h>
+
+/*
+ * The LM92 and MAX6635 have 2 two-state pins for address selection,
+ * resulting in 4 possible addresses.
+ */
+static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
+ I2C_CLIENT_END };
+
+/* The LM92 registers */
+#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
+#define LM92_REG_TEMP 0x00 /* 16-bit, RO */
+#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
+#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
+#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
+#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
+#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
+
+/*
+ * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
+ * left-justified in 16-bit registers. No rounding is done, with such
+ * a resolution it's just not worth it. Note that the MAX6635 doesn't
+ * make use of the 4 lower bits for limits (i.e. effective resolution
+ * for limits is 1 degree Celsius).
+ */
+static inline int TEMP_FROM_REG(s16 reg)
+{
+ return reg / 8 * 625 / 10;
+}
+
+static inline s16 TEMP_TO_REG(long val)
+{
+ val = clamp_val(val, -60000, 160000);
+ return val * 10 / 625 * 8;
+}
+
+/* Alarm flags are stored in the 3 LSB of the temperature register */
+static inline u8 ALARMS_FROM_REG(s16 reg)
+{
+ return reg & 0x0007;
+}
+
+enum temp_index {
+ t_input,
+ t_crit,
+ t_min,
+ t_max,
+ t_hyst,
+ t_num_regs
+};
+
+static const u8 regs[t_num_regs] = {
+ [t_input] = LM92_REG_TEMP,
+ [t_crit] = LM92_REG_TEMP_CRIT,
+ [t_min] = LM92_REG_TEMP_LOW,
+ [t_max] = LM92_REG_TEMP_HIGH,
+ [t_hyst] = LM92_REG_TEMP_HYST,
+};
+
+/* Client data (each client gets its own) */
+struct lm92_data {
+ struct i2c_client *client;
+ struct mutex update_lock;
+ char valid; /* zero until following fields are valid */
+ unsigned long last_updated; /* in jiffies */
+
+ /* registers values */
+ s16 temp[t_num_regs]; /* index with enum temp_index */
+};
+
+/*
+ * Sysfs attributes and callback functions
+ */
+
+static struct lm92_data *lm92_update_device(struct device *dev)
+{
+ struct lm92_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ int i;
+
+ mutex_lock(&data->update_lock);
+
+ if (time_after(jiffies, data->last_updated + HZ)
+ || !data->valid) {
+ dev_dbg(&client->dev, "Updating lm92 data\n");
+ for (i = 0; i < t_num_regs; i++) {
+ data->temp[i] =
+ i2c_smbus_read_word_swapped(client, regs[i]);
+ }
+ 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 *devattr,
+ char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+ struct lm92_data *data = lm92_update_device(dev);
+
+ return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
+}
+
+static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
+ const char *buf, size_t count)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+ struct lm92_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ int nr = attr->index;
+ long val;
+ int err;
+
+ err = kstrtol(buf, 10, &val);
+ if (err)
+ return err;
+
+ mutex_lock(&data->update_lock);
+ data->temp[nr] = TEMP_TO_REG(val);
+ i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
+ mutex_unlock(&data->update_lock);
+ return count;
+}
+
+static ssize_t show_temp_hyst(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+ struct lm92_data *data = lm92_update_device(dev);
+ return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
+ - TEMP_FROM_REG(data->temp[t_hyst]));
+}
+
+static ssize_t show_temp_min_hyst(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct lm92_data *data = lm92_update_device(dev);
+ return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
+ + TEMP_FROM_REG(data->temp[t_hyst]));
+}
+
+static ssize_t set_temp_hyst(struct device *dev,
+ struct device_attribute *devattr,
+ const char *buf, size_t count)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+ struct lm92_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ long val;
+ int err;
+
+ err = kstrtol(buf, 10, &val);
+ if (err)
+ return err;
+
+ val = clamp_val(val, -120000, 220000);
+ mutex_lock(&data->update_lock);
+ data->temp[t_hyst] =
+ TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
+ i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
+ data->temp[t_hyst]);
+ mutex_unlock(&data->update_lock);
+ return count;
+}
+
+static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct lm92_data *data = lm92_update_device(dev);
+ return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
+}
+
+static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ int bitnr = to_sensor_dev_attr(attr)->index;
+ struct lm92_data *data = lm92_update_device(dev);
+ return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1);
+}
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input);
+static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp,
+ t_crit);
+static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst,
+ set_temp_hyst, t_crit);
+static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp,
+ t_min);
+static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp_min_hyst, NULL);
+static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp,
+ t_max);
+static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);
+static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
+static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
+
+/*
+ * Detection and registration
+ */
+
+static void lm92_init_client(struct i2c_client *client)
+{
+ u8 config;
+
+ /* Start the conversions if needed */
+ config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
+ if (config & 0x01)
+ i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
+ config & 0xFE);
+}
+
+/*
+ * The MAX6635 has no identification register, so we have to use tricks
+ * to identify it reliably. This is somewhat slow.
+ * Note that we do NOT rely on the 2 MSB of the configuration register
+ * always reading 0, as suggested by the datasheet, because it was once
+ * reported not to be true.
+ */
+static int max6635_check(struct i2c_client *client)
+{
+ u16 temp_low, temp_high, temp_hyst, temp_crit;
+ u8 conf;
+ int i;
+
+ /*
+ * No manufacturer ID register, so a read from this address will
+ * always return the last read value.
+ */
+ temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
+ if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
+ return 0;
+ temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
+ if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
+ return 0;
+
+ /* Limits are stored as integer values (signed, 9-bit). */
+ if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
+ return 0;
+ temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
+ temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
+ if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
+ return 0;
+
+ /*
+ * Registers addresses were found to cycle over 16-byte boundaries.
+ * We don't test all registers with all offsets so as to save some
+ * reads and time, but this should still be sufficient to dismiss
+ * non-MAX6635 chips.
+ */
+ conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
+ for (i = 16; i < 96; i *= 2) {
+ if (temp_hyst != i2c_smbus_read_word_data(client,
+ LM92_REG_TEMP_HYST + i - 16)
+ || temp_crit != i2c_smbus_read_word_data(client,
+ LM92_REG_TEMP_CRIT + i)
+ || temp_low != i2c_smbus_read_word_data(client,
+ LM92_REG_TEMP_LOW + i + 16)
+ || temp_high != i2c_smbus_read_word_data(client,
+ LM92_REG_TEMP_HIGH + i + 32)
+ || conf != i2c_smbus_read_byte_data(client,
+ LM92_REG_CONFIG + i))
+ return 0;
+ }
+
+ return 1;
+}
+
+static struct attribute *lm92_attrs[] = {
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ &sensor_dev_attr_temp1_crit.dev_attr.attr,
+ &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
+ &sensor_dev_attr_temp1_min.dev_attr.attr,
+ &dev_attr_temp1_min_hyst.attr,
+ &sensor_dev_attr_temp1_max.dev_attr.attr,
+ &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
+ &dev_attr_alarms.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
+};
+ATTRIBUTE_GROUPS(lm92);
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int lm92_detect(struct i2c_client *new_client,
+ struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = new_client->adapter;
+ u8 config;
+ u16 man_id;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
+ | I2C_FUNC_SMBUS_WORD_DATA))
+ return -ENODEV;
+
+ config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
+ man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
+
+ if ((config & 0xe0) == 0x00 && man_id == 0x0180)
+ pr_info("lm92: Found National Semiconductor LM92 chip\n");
+ else if (max6635_check(new_client))
+ pr_info("lm92: Found Maxim MAX6635 chip\n");
+ else
+ return -ENODEV;
+
+ strlcpy(info->type, "lm92", I2C_NAME_SIZE);
+
+ return 0;
+}
+
+static int lm92_probe(struct i2c_client *new_client,
+ const struct i2c_device_id *id)
+{
+ struct device *hwmon_dev;
+ struct lm92_data *data;
+
+ data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->client = new_client;
+ mutex_init(&data->update_lock);
+
+ /* Initialize the chipset */
+ lm92_init_client(new_client);
+
+ hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
+ new_client->name,
+ data, lm92_groups);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+
+/*
+ * Module and driver stuff
+ */
+
+static const struct i2c_device_id lm92_id[] = {
+ { "lm92", 0 },
+ /* max6635 could be added here */
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, lm92_id);
+
+static struct i2c_driver lm92_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "lm92",
+ },
+ .probe = lm92_probe,
+ .id_table = lm92_id,
+ .detect = lm92_detect,
+ .address_list = normal_i2c,
+};
+
+module_i2c_driver(lm92_driver);
+
+MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
+MODULE_DESCRIPTION("LM92/MAX6635 driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff