hwmon: (lm73) Add 'update_interval' attribute
The LM73 supports four A/D conversion resolutions. The default used by
the existing lm73 driver is the chip's default, 11-bit (0.25 C/LSB).
This patch enables changing of this resolution from userspace via the
update_interval sysfs attribute. Full details on usage are included in
Documentation/hwmon/lm73.
Signed-off-by: Chris Verges <kg4ysn@gmail.com>
[linux@roeck-us.net: cleanup]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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 @@
#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 @@
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 @@
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 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 @@
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;
}