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-rw-r--r--Documentation/hwmon/lm7379
-rw-r--r--drivers/hwmon/lm73.c97
2 files changed, 165 insertions, 11 deletions
diff --git a/Documentation/hwmon/lm73 b/Documentation/hwmon/lm73
new file mode 100644
index 0000000..782b3e1
--- /dev/null
+++ b/Documentation/hwmon/lm73
@@ -0,0 +1,79 @@
+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: Guillaume Ligneul <guillaume.ligneul@gmail.com>
+Documentation: Chris Verges <kg4ysn@gmail.com>
+
+
+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..14
+ 0.125 28 15..28
+ 0.0625 56 29..56
+ 0.03125 112 57..infinity
+ --------------------------------------
+
+The following examples show how the 'update_interval' attribute can be
+used to change the conversion time:
+
+ $ echo 0 > update_interval
+ $ cat update_interval
+ 14
+ $ cat temp1_input
+ 24250
+
+ $ echo 22 > update_interval
+ $ cat update_interval
+ 28
+ $ cat temp1_input
+ 24125
+
+ $ echo 56 > update_interval
+ $ cat update_interval
+ 56
+ $ cat temp1_input
+ 24062
+
+ $ echo 85 > update_interval
+ $ cat 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.
diff --git a/drivers/hwmon/lm73.c b/drivers/hwmon/lm73.c
index dad83fe..0b19f03 100644
--- a/drivers/hwmon/lm73.c
+++ b/drivers/hwmon/lm73.c
@@ -39,8 +39,24 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
#define LM73_TEMP_MIN (-256000 / 250)
#define LM73_TEMP_MAX (255750 / 250)
-/*-----------------------------------------------------------------------*/
+#define LM73_CTRL_RES_SHIFT 5
+#define LM73_CTRL_RES_MASK (BIT(5) | BIT(6))
+#define LM73_CTRL_TO_MASK BIT(7)
+
+static const unsigned short lm73_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 */
+};
+
+struct lm73_data {
+ struct device *hwmon_dev;
+ struct mutex lock;
+ u8 ctrl; /* control register value */
+};
+/*-----------------------------------------------------------------------*/
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
@@ -78,6 +94,51 @@ 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);
+ struct lm73_data *data = i2c_get_clientdata(client);
+ unsigned long convrate;
+ s32 err;
+ int res = 0;
+
+ err = kstrtoul(buf, 10, &convrate);
+ if (err < 0)
+ return err;
+
+ /*
+ * Convert the desired conversion rate into register bits.
+ * res is already initialized, and everything past the second-to-last
+ * value in the array is treated as belonging to the last value
+ * in the array.
+ */
+ while (res < (ARRAY_SIZE(lm73_convrates) - 1) &&
+ convrate > lm73_convrates[res])
+ res++;
+
+ mutex_lock(&data->lock);
+ data->ctrl &= LM73_CTRL_TO_MASK;
+ data->ctrl |= res << LM73_CTRL_RES_SHIFT;
+ err = i2c_smbus_write_byte_data(client, LM73_REG_CTRL, data->ctrl);
+ mutex_unlock(&data->lock);
+
+ 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);
+ struct lm73_data *data = i2c_get_clientdata(client);
+ int res;
+
+ res = (data->ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT;
+ return scnprintf(buf, PAGE_SIZE, "%hu\n", lm73_convrates[res]);
+}
/*-----------------------------------------------------------------------*/
@@ -89,13 +150,14 @@ 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(update_interval, S_IWUSR | S_IRUGO,
+ show_convrate, set_convrate, 0);
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_update_interval.dev_attr.attr,
NULL
};
@@ -110,23 +172,36 @@ static const struct attribute_group lm73_group = {
static int
lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
- struct device *hwmon_dev;
int status;
+ struct lm73_data *data;
+ int ctrl;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct lm73_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, data);
+ mutex_init(&data->lock);
+
+ ctrl = i2c_smbus_read_byte_data(client, LM73_REG_CTRL);
+ if (ctrl < 0)
+ return ctrl;
+ data->ctrl = ctrl;
/* Register sysfs hooks */
status = sysfs_create_group(&client->dev.kobj, &lm73_group);
if (status)
return status;
- hwmon_dev = hwmon_device_register(&client->dev);
- if (IS_ERR(hwmon_dev)) {
- status = PTR_ERR(hwmon_dev);
+ data->hwmon_dev = hwmon_device_register(&client->dev);
+ if (IS_ERR(data->hwmon_dev)) {
+ status = PTR_ERR(data->hwmon_dev);
goto exit_remove;
}
- i2c_set_clientdata(client, hwmon_dev);
dev_info(&client->dev, "%s: sensor '%s'\n",
- dev_name(hwmon_dev), client->name);
+ dev_name(data->hwmon_dev), client->name);
return 0;
@@ -137,9 +212,9 @@ exit_remove:
static int lm73_remove(struct i2c_client *client)
{
- struct device *hwmon_dev = i2c_get_clientdata(client);
+ struct lm73_data *data = i2c_get_clientdata(client);
- hwmon_device_unregister(hwmon_dev);
+ hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &lm73_group);
return 0;
}