added error handling so if lm80_update_device fails
an error is returned when reading the value through sysfs
This is closely modeled after the way this is handled in ltc4261
Note: if update gets an error, this error is returned for all
registers and no further reads are done.
If a register is not accessible most likely the whole device
is broken or disconnected and it is definitely interesting to know.
Note2: I added a macro to read and handle errors. This was felt to
be the simplest. If someone feels it should be done using a
subroutine, be my guest.
Signed-off-by: Frans Meulenbroeks <fransmeulenbroeks@xxxxxxxxx>
---
patch is against the hwmon staging tree
git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git
as retrieved on jan 2, 2012
drivers/hwmon/lm80.c | 97 ++++++++++++++++++++++++++++++++++---------------
1 files changed, 67 insertions(+), 30 deletions(-)
diff --git a/drivers/hwmon/lm80.c b/drivers/hwmon/lm80.c
index 18a0e6c..5283b27 100644
--- a/drivers/hwmon/lm80.c
+++ b/drivers/hwmon/lm80.c
@@ -168,6 +168,8 @@ static ssize_t show_in_##suffix(struct device *dev, struct device_attribute *att
{ \
int nr = to_sensor_dev_attr(attr)->index; \
struct lm80_data *data = lm80_update_device(dev); \
+ if (IS_ERR(data)) \
+ return PTR_ERR(data); \
return sprintf(buf, "%d\n", IN_FROM_REG(data->value[nr])); \
}
show_in(min, in_min)
@@ -197,6 +199,8 @@ static ssize_t show_fan_##suffix(struct device *dev, struct device_attribute *at
{ \
int nr = to_sensor_dev_attr(attr)->index; \
struct lm80_data *data = lm80_update_device(dev); \
+ if (IS_ERR(data)) \
+ return PTR_ERR(data); \
return sprintf(buf, "%d\n", FAN_FROM_REG(data->value[nr], \
DIV_FROM_REG(data->fan_div[nr]))); \
}
@@ -208,6 +212,8 @@ static ssize_t show_fan_div(struct device *dev, struct device_attribute *attr,
{
int nr = to_sensor_dev_attr(attr)->index;
struct lm80_data *data = lm80_update_device(dev);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
return sprintf(buf, "%d\n", DIV_FROM_REG(data->fan_div[nr]));
}
@@ -271,6 +277,8 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr,
static ssize_t show_temp_input1(struct device *dev, struct device_attribute *attr, char *buf)
{
struct lm80_data *data = lm80_update_device(dev);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
return sprintf(buf, "%ld\n", TEMP_FROM_REG(data->temp));
}
@@ -278,6 +286,8 @@ static ssize_t show_temp_input1(struct device *dev, struct device_attribute *att
static ssize_t show_temp_##suffix(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
struct lm80_data *data = lm80_update_device(dev); \
+ if (IS_ERR(data)) \
+ return PTR_ERR(data); \
return sprintf(buf, "%d\n", TEMP_LIMIT_FROM_REG(data->value)); \
}
show_temp(hot_max, temp_hot_max);
@@ -308,6 +318,8 @@ static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm80_data *data = lm80_update_device(dev);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
return sprintf(buf, "%u\n", data->alarms);
}
@@ -316,6 +328,8 @@ static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
{
int bitnr = to_sensor_dev_attr(attr)->index;
struct lm80_data *data = lm80_update_device(dev);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
}
@@ -544,55 +558,78 @@ static void lm80_init_client(struct i2c_client *client)
lm80_write_value(client, LM80_REG_CONFIG, 0x01);
}
+/*
+ Note: safe_lm80_read_value is a helper macro for lm80_update_device
+ It reads a value using lm80_read_value and jumps to abort
+ in case of an error.
+ Due to this jump and because it modifies the first arguement
+ it has to be a macro
+*/
+#define safe_lm80_read_value(var, client, reg) \
+ { \
+ status = lm80_read_value(client, reg); \
+ if (unlikely(status < 0)) { \
+ dev_dbg(dev, \
+ "LM80: Failed to read value: reg %d, error %d\n", \
+ reg, status); \
+ ret = ERR_PTR(status); \
+ data->valid = 0; \
+ goto abort; \
+ } \
+ else \
+ var = status; \
+ }
+
static struct lm80_data *lm80_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm80_data *data = i2c_get_clientdata(client);
+ struct lm80_data *ret = data;
int i;
+ int status;
+ int tmp1, tmp2;
mutex_lock(&data->update_lock);
+ if (!data->valid)
+ {
+ /* last time failed: re-initialize the LM80 chip */
+ lm80_init_client(client);
+ }
if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
dev_dbg(&client->dev, "Starting lm80 update\n");
for (i = 0; i <= 6; i++) {
- data->in[i] =
- lm80_read_value(client, LM80_REG_IN(i));
- data->in_min[i] =
- lm80_read_value(client, LM80_REG_IN_MIN(i));
- data->in_max[i] =
- lm80_read_value(client, LM80_REG_IN_MAX(i));
+ safe_lm80_read_value(data->in[i], client, LM80_REG_IN(i));
+ safe_lm80_read_value(data->in_min[i], client, LM80_REG_IN_MIN(i));
+ safe_lm80_read_value(data->in_max[i], client, LM80_REG_IN_MAX(i));
}
- data->fan[0] = lm80_read_value(client, LM80_REG_FAN1);
- data->fan_min[0] =
- lm80_read_value(client, LM80_REG_FAN_MIN(1));
- data->fan[1] = lm80_read_value(client, LM80_REG_FAN2);
- data->fan_min[1] =
- lm80_read_value(client, LM80_REG_FAN_MIN(2));
-
- data->temp =
- (lm80_read_value(client, LM80_REG_TEMP) << 8) |
- (lm80_read_value(client, LM80_REG_RES) & 0xf0);
- data->temp_os_max =
- lm80_read_value(client, LM80_REG_TEMP_OS_MAX);
- data->temp_os_hyst =
- lm80_read_value(client, LM80_REG_TEMP_OS_HYST);
- data->temp_hot_max =
- lm80_read_value(client, LM80_REG_TEMP_HOT_MAX);
- data->temp_hot_hyst =
- lm80_read_value(client, LM80_REG_TEMP_HOT_HYST);
-
- i = lm80_read_value(client, LM80_REG_FANDIV);
+ safe_lm80_read_value(data->fan[0], client, LM80_REG_FAN1);
+ safe_lm80_read_value(data->fan_min[0], client, LM80_REG_FAN_MIN(1));
+ safe_lm80_read_value(data->fan[1], client, LM80_REG_FAN2);
+ safe_lm80_read_value(data->fan_min[1], client, LM80_REG_FAN_MIN(2));
+
+ safe_lm80_read_value(tmp1, client, LM80_REG_TEMP);
+ safe_lm80_read_value(tmp2, client, LM80_REG_RES);
+ data->temp = (tmp1 << 8) | (tmp2 ^ 0xf0);
+
+ safe_lm80_read_value(data->temp_os_max, client, LM80_REG_TEMP_OS_MAX);
+ safe_lm80_read_value(data->temp_os_hyst, client, LM80_REG_TEMP_OS_HYST);
+ safe_lm80_read_value(data->temp_hot_max, client, LM80_REG_TEMP_HOT_MAX);
+ safe_lm80_read_value(data->temp_hot_hyst, client, LM80_REG_TEMP_HOT_HYST);
+
+ safe_lm80_read_value(i, client, LM80_REG_FANDIV);
data->fan_div[0] = (i >> 2) & 0x03;
data->fan_div[1] = (i >> 4) & 0x03;
- data->alarms = lm80_read_value(client, LM80_REG_ALARM1) +
- (lm80_read_value(client, LM80_REG_ALARM2) << 8);
+ safe_lm80_read_value(tmp1, client, LM80_REG_ALARM1);
+ safe_lm80_read_value(tmp2, client, LM80_REG_ALARM2);
+ data->alarms = tmp1 + (tmp2 << 8);
data->last_updated = jiffies;
data->valid = 1;
}
+abort:
mutex_unlock(&data->update_lock);
-
- return data;
+ return ret;
}
static int __init sensors_lm80_init(void)
--
1.7.0.4
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