The LM73 also supports a basic over-temperature indicator. When the
measured temperature goes above the high temperature limit, temp1_max,
the alarm is triggered. When it drops below the low temperature limit,
temp1_min, the alarm is ended.
Full details on use of these mechanisms are described in
Documentation/hwmon/lm73.
Signed-off-by: Chris Verges <kg4ysn@xxxxxxxxx>
---
Documentation/hwmon/lm73 | 108 +++++++++++++++
drivers/hwmon/lm73.c | 263
+++++++++++++++++++++++++++++++++++-
include/linux/platform_data/lm73.h | 38 ++++++
3 files changed, 405 insertions(+), 4 deletions(-)
create mode 100644 Documentation/hwmon/lm73
create mode 100644 include/linux/platform_data/lm73.h
diff --git a/Documentation/hwmon/lm73 b/Documentation/hwmon/lm73
new file mode 100644
index 0000000..24dfd8a
--- /dev/null
+++ b/Documentation/hwmon/lm73
@@ -0,0 +1,108 @@
+Kernel driver lm73
+==================
+
+Supported chips:
+ * Texas Instruments LM73
+ Prefix: 'lm73'
+ Addresses scanned: I2C 0x48, 0x49, 0x4a, 0x4c, 0x4d, and 0x4e
+ Datasheet: Publicly available at the Texas Instruments website
+ http://www.ti.com/product/lm73
+
+Author: Chris Verges <kg4ysn@xxxxxxxxx>
+
+
+Description
+-----------
+
+The LM73 is a digital temperature sensor. All temperature values are
+given in degrees Celsius.
+
+Measurement Resolution Support
+------------------------------
+
+The LM73 supports four resolutions, defined in terms of degrees C per
+LSB: 0.25, 0.125, 0.0625, and 0.3125. Changing the resolution mode
+affects the conversion time of the LM73's analog-to-digital converter.
+From userspace, the desired resolution can be specified as a function of
+conversion time via the 'update_interval' sysfs attribute for the
+device. This attribute will normalize ranges of input values to the
+maximum times defined for the resolution in the datasheet.
+
+ Resolution Conv. Time Input Range
+ (C/LSB) (msec) (msec)
+ --------------------------------------
+ 0.25 14 0..21
+ 0.125 28 22..42
+ 0.0625 56 43..84
+ 0.03125 112 85..infinity
+ --------------------------------------
+
+The following examples show how the 'update_interval' attribute can be
+used to change the conversion time:
+
+ $ echo 0 > temp1_update_interval
+ $ cat temp1_update_interval
+ 14
+ $ cat temp1_input
+ 24250
+
+ $ echo 36 > temp1_update_interval
+ $ cat temp1_update_interval
+ 28
+ $ cat temp1_input
+ 24125
+
+ $ echo 56 > temp1_update_interval
+ $ cat temp1_update_interval
+ 56
+ $ cat temp1_input
+ 24062
+
+ $ echo 85 > temp1_update_interval
+ $ cat temp1_update_interval
+ 112
+ $ cat temp1_input
+ 24031
+
+As shown here, the lm73 driver automatically adjusts any user input for
+'update_interval' via a step function. Reading back the
+'update_interval' value after a write operation will confirm the
+conversion time actively in use.
+
+Mathematically, the resolution can be derived from the conversion time
+via the following function:
+
+ g(x) = 0.250 * [log(x/14) / log(2)]
+
+where 'x' is the output from 'update_interval' and 'g(x)' is the
+resolution in degrees C per LSB.
+
+Alarm Support
+-------------
+
+The LM73 features a simple over-temperature alarm mechanism. This
+feature is exposed via the sysfs attributes and (optionally) via
+platform device interrupt handling hooks.
+
+The primary attribute is 'temp1_alarm.' When the measured temperature
+exceeds the value stored in 'temp1_max', the alarm triggers. When the
+measured temperature drops below the value stored in 'temp1_min', the
+alarm is cleared. The alarm can also be cleared by writing a '0' to the
+'temp1_alarm' attribute.
+
+The attributes 'temp1_max_alarm' and 'temp1_min_alarm' are flags
+provided by the LM73 that indicate whether the measured temperature has
+passed the 'temp1_max' and 'temp1_min' thresholds, respectively. These
+values _must_ be read to clear the registers on the LM73.
+
+If the lm73 driver is provided a struct lm73_platform_data during
+initialization, interrupt handling is enabled. The platform must define
+the IRQ number and IRQ flags at a minimum, and can optionally also
+define a callback function to supplement the IRQ handler provided by the
+lm73 driver. This internal IRQ handler enables use of epoll() on the
+'temp1_alarm' attribute via the sysfs_notify() method.
+
+Finally, the LM73 can set the polarity of the ALERT interrupt to either
+active-high or active-low (default). If the platform desired the
+polarity to be switched to active-high, it can declare this in the
+struct lm73_platform_data used during initialization.
diff --git a/drivers/hwmon/lm73.c b/drivers/hwmon/lm73.c
index 7272176..4acb0e2 100644
--- a/drivers/hwmon/lm73.c
+++ b/drivers/hwmon/lm73.c
@@ -20,7 +20,8 @@
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
-
+#include <linux/interrupt.h>
+#include <linux/platform_data/lm73.h>
/* Addresses scanned */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
@@ -39,8 +40,91 @@ static const unsigned short normal_i2c[] = {
0x48, 0x49, 0x4a, 0x4c,
#define LM73_TEMP_MIN (-40)
#define LM73_TEMP_MAX 150
+#define LM73_CTRL_RES_SHIFT 5
+#define LM73_CTRL_RES_SIZE 2
+#define LM73_CTRL_RES_MASK \
+ (((1 << LM73_CTRL_RES_SIZE) - 1) << LM73_CTRL_RES_SHIFT)
+
+#define LM73_CTRL_ALERT_SHIFT 3
+#define LM73_CTRL_ALERT_SIZE 1
+#define LM73_CTRL_ALERT_MASK \
+ (((1 << LM73_CTRL_ALERT_SIZE) - 1) << LM73_CTRL_ALERT_SHIFT)
+
+#define LM73_CTRL_HI_SHIFT 2
+#define LM73_CTRL_HI_SIZE 1
+#define LM73_CTRL_HI_MASK \
+ (((1 << LM73_CTRL_HI_SIZE) - 1) << LM73_CTRL_HI_SHIFT)
+
+#define LM73_CTRL_LO_SHIFT 1
+#define LM73_CTRL_LO_SIZE 1
+#define LM73_CTRL_LO_MASK \
+ (((1 << LM73_CTRL_LO_SIZE) - 1) << LM73_CTRL_LO_SHIFT)
+
+#define LM73_CTRL_HILO_MASK \
+ (LM73_CTRL_HI_MASK | LM73_CTRL_LO_MASK)
+
+#define LM73_CONF_POL_SHIFT 4
+#define LM73_CONF_POL_SIZE 1
+#define LM73_CONF_POL_MASK \
+ (((1 << LM73_CONF_POL_SIZE) - 1) << LM73_CONF_POL_SHIFT)
+
+#define LM73_CONF_RESET_SHIFT 3
+#define LM73_CONF_RESET_SIZE 1
+#define LM73_CONF_RESET_MASK \
+ (((1 << LM73_CONF_RESET_SIZE) - 1) << LM73_CONF_RESET_SHIFT)
+
+#define SCALE_150_PERCENT(x) ((x) + (x)/2)
+
+static const unsigned short lm73_valid_convrates[] = {
+ 14, /* 11-bits (0.25000 C/LSB): RES1 Bit = 0, RES0 Bit = 0 */
+ 28, /* 12-bits (0.12500 C/LSB): RES1 Bit = 0, RES0 Bit = 1 */
+ 56, /* 13-bits (0.06250 C/LSB): RES1 Bit = 1, RES0 Bit = 0 */
+ 112, /* 14-bits (0.03125 C/LSB): RES1 Bit = 1, RES0 Bit = 1 */
+};
+
/*-----------------------------------------------------------------------*/
+/* utility functions */
+
+static inline s32 lm73_read(struct i2c_client *client, u8 reg)
+{
+ return i2c_smbus_read_byte_data(client, reg);
+}
+
+static inline s32 lm73_write(struct i2c_client *client, u8 reg,
+ u8 clear, u8 enable)
+{
+ s32 tmp = lm73_read(client, reg);
+ u8 value;
+ if (tmp < 0)
+ return tmp;
+ value = tmp;
+ value &= ~clear;
+ value |= enable;
+ return i2c_smbus_write_byte_data(client, reg, value);
+}
+
+static inline s32 lm73_write_conf(struct i2c_client *client, u8 clear,
+ u8 enable)
+{
+ /* always clear bits 1:0 and set bit 6 */
+ enable &= ~(3 << 0);
+ return lm73_write(client, LM73_REG_CONF,
+ clear | (3 << 0),
+ enable | (1 << 6));
+}
+
+static inline s32 lm73_write_ctrl(struct i2c_client *client, u8 clear,
+ u8 enable)
+{
+ /* always clear bits 4:3 and 0 */
+ enable &= ~((3 << 3) | (1 << 0));
+ return lm73_write(client, LM73_REG_CTRL,
+ clear | (3 << 3) | (1 << 0),
+ enable);
+}
+
+/*-----------------------------------------------------------------------*/
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
@@ -59,7 +143,9 @@ static ssize_t set_temp(struct device *dev,
struct device_attribute *da,
value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4),
(LM73_TEMP_MAX*4)) << 5;
err = i2c_smbus_write_word_swapped(client, attr->index, value);
- return (err < 0) ? err : count;
+ if (err < 0)
+ return err;
+ return count;
}
static ssize_t show_temp(struct device *dev, struct device_attribute *da,
@@ -79,6 +165,121 @@ static ssize_t show_temp(struct device *dev,
struct device_attribute *da,
return scnprintf(buf, PAGE_SIZE, "%d\n", temp);
}
+static ssize_t set_convrate(struct device *dev, struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned long convrate;
+ s32 err;
+ u8 res_bits = 0;
+
+ err = kstrtoul(buf, 10, &convrate);
+ if (err < 0)
+ return err;
+
+ /* Convert the desired conversion rate into register bits */
+ if (convrate < SCALE_150_PERCENT(lm73_valid_convrates[0]))
+ res_bits = 0;
+ else if (convrate < SCALE_150_PERCENT(lm73_valid_convrates[1]))
+ res_bits = 1;
+ else if (convrate < SCALE_150_PERCENT(lm73_valid_convrates[2]))
+ res_bits = 2;
+ else
+ res_bits = 3;
+
+ err = lm73_write_ctrl(client, LM73_CTRL_RES_MASK,
+ res_bits << LM73_CTRL_RES_SHIFT);
+ if (err < 0)
+ return err;
+
+ return count;
+}
+
+static ssize_t show_convrate(struct device *dev, struct
device_attribute *da,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ s32 ctrl;
+ u8 res_bits = 0;
+
+ /* Read existing control value */
+ ctrl = lm73_read(client, LM73_REG_CTRL);
+ if (ctrl < 0)
+ return ctrl;
+
+ res_bits = (ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT;
+ return scnprintf(buf, PAGE_SIZE, "%hu\n",
+ lm73_valid_convrates[res_bits]);
+}
+
+static ssize_t reset_alarm(struct device *dev, struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned long input;
+ s32 err;
+
+ err = kstrtoul(buf, 10, &input);
+ if (err < 0)
+ return err;
+
+ /* ignore everything but a reset request */
+ if (input)
+ return -EINVAL;
+
+ err = lm73_write_conf(client, 0, LM73_CONF_RESET_MASK);
+ if (err < 0)
+ return err;
+ return count;
+}
+
+static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ s32 ctrl;
+ s32 conf;
+
+ ctrl = lm73_read(client, LM73_REG_CTRL);
+ if (ctrl < 0)
+ return ctrl;
+
+ conf = lm73_read(client, LM73_REG_CONF);
+ if (conf < 0)
+ return conf;
+
+ /* strip out just the ALERT bit */
+ ctrl &= LM73_CTRL_ALERT_MASK;
+ ctrl >>= LM73_CTRL_ALERT_SHIFT;
+
+ /*
+ * If ALERT's polarity is active-low, the bit needs to be
+ * flipped to match the semantics of the 'alarm' attribute.
+ */
+ if (!(conf & LM73_CONF_POL_MASK))
+ ctrl = !ctrl;
+
+ return scnprintf(buf, PAGE_SIZE, "%d\n", ctrl);
+}
+
+static ssize_t show_maxmin_alarm(struct device *dev,
+ struct device_attribute *da,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ s32 ctrl;
+
+ ctrl = lm73_read(client, LM73_REG_CTRL);
+ if (ctrl < 0)
+ return ctrl;
+
+ /* strip out just the temperature hi/lo flag */
+ ctrl >>= attr->index;
+ ctrl &= 0x1;
+
+ return scnprintf(buf, PAGE_SIZE, "%d\n", ctrl);
+}
/*-----------------------------------------------------------------------*/
@@ -90,13 +291,23 @@ static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
show_temp, set_temp, LM73_REG_MIN);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
show_temp, NULL, LM73_REG_INPUT);
-
+static SENSOR_DEVICE_ATTR(temp1_update_interval, S_IWUSR | S_IRUGO,
+ show_convrate, set_convrate, 0);
+static SENSOR_DEVICE_ATTR(temp1_alarm, S_IWUSR | S_IRUGO,
+ show_alarm, reset_alarm, 0);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
+ show_maxmin_alarm, NULL, LM73_CTRL_HI_SHIFT);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO,
+ show_maxmin_alarm, NULL, LM73_CTRL_LO_SHIFT);
static struct attribute *lm73_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
-
+ &sensor_dev_attr_temp1_update_interval.dev_attr.attr,
+ &sensor_dev_attr_temp1_alarm.dev_attr.attr,
+ &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+ &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
NULL
};
@@ -106,11 +317,25 @@ static const struct attribute_group lm73_group = {
/*-----------------------------------------------------------------------*/
+static irqreturn_t lm73_alarm_irq(int irq, void *arg)
+{
+ struct i2c_client *client = arg;
+ struct lm73_platform_data *data = client->dev.platform_data;
+
+ sysfs_notify(&client->dev.kobj, NULL, "temp1_alarm");
+ if (data && data->handler)
+ return data->handler(irq, arg);
+ return IRQ_HANDLED;
+}
+
+/*-----------------------------------------------------------------------*/
+
/* device probe and removal */
static int
lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
+ struct lm73_platform_data *data = client->dev.platform_data;
struct device *hwmon_dev;
int status;
@@ -126,6 +351,32 @@ lm73_probe(struct i2c_client *client, const
struct i2c_device_id *id)
}
i2c_set_clientdata(client, hwmon_dev);
+ if (data && data->alert_polarity_high) {
+ status = lm73_write_conf(client, 0, LM73_CONF_POL_MASK);
+ if (status < 0) {
+ dev_err(&client->dev,
+ "%s: unable to set ALERT polarity\n",
+ dev_name(hwmon_dev));
+ status = -EIO;
+ goto exit_remove;
+ }
+ }
+
+ if (data && data->use_irq) {
+ status = devm_request_irq(&client->dev,
+ data->irq,
+ lm73_alarm_irq,
+ data->irqflags,
+ dev_name(hwmon_dev),
+ client);
+ if (status < 0) {
+ dev_err(&client->dev,
+ "%s: unable to assign IRQ %d\n",
+ dev_name(hwmon_dev), data->irq);
+ goto exit_remove;
+ }
+ }
+
dev_info(&client->dev, "%s: sensor '%s'\n",
dev_name(hwmon_dev), client->name);
@@ -139,7 +390,11 @@ exit_remove:
static int lm73_remove(struct i2c_client *client)
{
struct device *hwmon_dev = i2c_get_clientdata(client);
+ struct lm73_platform_data *data = client->dev.platform_data;
+ if (data && data->use_irq)
+ devm_free_irq(&client->dev, data->use_irq,
+ data->handler);
hwmon_device_unregister(hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &lm73_group);
return 0;
diff --git a/include/linux/platform_data/lm73.h
b/include/linux/platform_data/lm73.h
new file mode 100644
index 0000000..bfe9382
--- /dev/null
+++ b/include/linux/platform_data/lm73.h
@@ -0,0 +1,38 @@
+/*
+ * LM73 Sensor driver
+ * Based on LM75
+ *
+ * Copyright (C) 2007, CenoSYS (www.cenosys.com).
+ * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
+ *
+ * Guillaume Ligneul <guillaume.ligneul@xxxxxxxxx>
+ * Adrien Demarez <adrien.demarez@xxxxxxxxxxxxxxxxx>
+ * Jeremy Laine <jeremy.laine@xxxxxxxxxxxxxxxxx>
+ *
+ * This software program is licensed subject to the GNU General
Public License
+ * (GPL).Version 2,June 1991, available at
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ */
+#ifndef _LINUX_LM73_H
+#define _LINUX_LM73_H
+
+/**
+ * struct lm73_platform_data - static configuration settings for the
+ * LM73 temperature sensor.
+ *
+ * @alert_polarity_high: 0 if ALERT is active-high, 1 if active-low
+ * @use_irq: 0 if ALERT is wired to an active interrupt pin
+ * @irq: the interrupt to use
+ * @irqflags: the interrupt flags (see IRQF_*)
+ * @handler: the platform handler function
+ */
+struct lm73_platform_data {
+ int alert_polarity_high;
+
+ int use_irq;
+ unsigned int irq;
+ unsigned long irqflags;
+ irq_handler_t handler;
+};
+
+#endif /* _LINUX_LM73_H */
--
1.7.9.5
