diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst index 037b69c23cb5..1d7f1397a827 100644 --- a/Documentation/hwmon/hwmon-kernel-api.rst +++ b/Documentation/hwmon/hwmon-kernel-api.rst @@ -42,6 +42,9 @@ register/unregister functions:: char *devm_hwmon_sanitize_name(struct device *dev, const char *name); + void hwmon_lock(struct device *dev); + void hwmon_unlock(struct device *dev); + hwmon_device_register_with_info registers a hardware monitoring device. It creates the standard sysfs attributes in the hardware monitoring core, letting the driver focus on reading from and writing to the chip instead @@ -79,6 +82,13 @@ devm_hwmon_sanitize_name is the resource managed version of hwmon_sanitize_name; the memory will be freed automatically on device removal. +When using ``[devm_]hwmon_device_register_with_info()`` to register the +hardware monitoring device, accesses using the associated access functions +are serialised by the hardware monitoring core. If a driver needs locking +for other functions such as interrupt handlers or for attributes which are +fully implemented in the driver, hwmon_lock() and hwmon_unlock() can be used +to ensure that calls to those functions are serialized. + Using devm_hwmon_device_register_with_info() -------------------------------------------- diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c index 2e17f3a4c59b..0b4bdcd33c7b 100644 --- a/drivers/hwmon/hwmon.c +++ b/drivers/hwmon/hwmon.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -36,6 +37,7 @@ struct hwmon_device { const char *label; struct device dev; const struct hwmon_chip_info *chip; + struct mutex lock; struct list_head tzdata; struct attribute_group group; const struct attribute_group **groups; @@ -165,6 +167,8 @@ static int hwmon_thermal_get_temp(struct thermal_zone_device *tz, int *temp) int ret; long t; + guard(mutex)(&hwdev->lock); + ret = hwdev->chip->ops->read(tdata->dev, hwmon_temp, hwmon_temp_input, tdata->index, &t); if (ret < 0) @@ -193,6 +197,8 @@ static int hwmon_thermal_set_trips(struct thermal_zone_device *tz, int low, int if (!info[i]) return 0; + guard(mutex)(&hwdev->lock); + if (info[i]->config[tdata->index] & HWMON_T_MIN) { err = chip->ops->write(tdata->dev, hwmon_temp, hwmon_temp_min, tdata->index, low); @@ -330,8 +336,6 @@ static int hwmon_attr_base(enum hwmon_sensor_types type) * attached to an i2c client device. */ -static DEFINE_MUTEX(hwmon_pec_mutex); - static int hwmon_match_device(struct device *dev, const void *data) { return dev->class == &hwmon_class; @@ -362,17 +366,16 @@ static ssize_t pec_store(struct device *dev, struct device_attribute *devattr, if (!hdev) return -ENODEV; - mutex_lock(&hwmon_pec_mutex); - /* * If there is no write function, we assume that chip specific * handling is not required. */ hwdev = to_hwmon_device(hdev); + guard(mutex)(&hwdev->lock); if (hwdev->chip->ops->write) { err = hwdev->chip->ops->write(hdev, hwmon_chip, hwmon_chip_pec, 0, val); if (err && err != -EOPNOTSUPP) - goto unlock; + goto put; } if (!val) @@ -381,8 +384,7 @@ static ssize_t pec_store(struct device *dev, struct device_attribute *devattr, client->flags |= I2C_CLIENT_PEC; err = count; -unlock: - mutex_unlock(&hwmon_pec_mutex); +put: put_device(hdev); return err; @@ -426,10 +428,13 @@ static ssize_t hwmon_attr_show(struct device *dev, struct device_attribute *devattr, char *buf) { struct hwmon_device_attribute *hattr = to_hwmon_attr(devattr); + struct hwmon_device *hwdev = to_hwmon_device(dev); s64 val64; long val; int ret; + guard(mutex)(&hwdev->lock); + ret = hattr->ops->read(dev, hattr->type, hattr->attr, hattr->index, (hattr->type == hwmon_energy64) ? (long *)&val64 : &val); if (ret < 0) @@ -449,10 +454,13 @@ static ssize_t hwmon_attr_show_string(struct device *dev, char *buf) { struct hwmon_device_attribute *hattr = to_hwmon_attr(devattr); + struct hwmon_device *hwdev = to_hwmon_device(dev); enum hwmon_sensor_types type = hattr->type; const char *s; int ret; + guard(mutex)(&hwdev->lock); + ret = hattr->ops->read_string(dev, hattr->type, hattr->attr, hattr->index, &s); if (ret < 0) @@ -469,6 +477,7 @@ static ssize_t hwmon_attr_store(struct device *dev, const char *buf, size_t count) { struct hwmon_device_attribute *hattr = to_hwmon_attr(devattr); + struct hwmon_device *hwdev = to_hwmon_device(dev); long val; int ret; @@ -476,6 +485,8 @@ static ssize_t hwmon_attr_store(struct device *dev, if (ret < 0) return ret; + guard(mutex)(&hwdev->lock); + ret = hattr->ops->write(dev, hattr->type, hattr->attr, hattr->index, val); if (ret < 0) @@ -791,6 +802,22 @@ int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type, } EXPORT_SYMBOL_GPL(hwmon_notify_event); +void hwmon_lock(struct device *dev) +{ + struct hwmon_device *hwdev = to_hwmon_device(dev); + + mutex_lock(&hwdev->lock); +} +EXPORT_SYMBOL_GPL(hwmon_lock); + +void hwmon_unlock(struct device *dev) +{ + struct hwmon_device *hwdev = to_hwmon_device(dev); + + mutex_unlock(&hwdev->lock); +} +EXPORT_SYMBOL_GPL(hwmon_unlock); + static int hwmon_num_channel_attrs(const struct hwmon_channel_info *info) { int i, n; @@ -951,6 +978,7 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata, tdev = tdev->parent; hdev->of_node = tdev ? tdev->of_node : NULL; hwdev->chip = chip; + mutex_init(&hwdev->lock); dev_set_drvdata(hdev, drvdata); dev_set_name(hdev, HWMON_ID_FORMAT, id); err = device_register(hdev); diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h index 886fc90b2d25..301a83afbd66 100644 --- a/include/linux/hwmon.h +++ b/include/linux/hwmon.h @@ -492,6 +492,9 @@ int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type, char *hwmon_sanitize_name(const char *name); char *devm_hwmon_sanitize_name(struct device *dev, const char *name); +void hwmon_lock(struct device *dev); +void hwmon_unlock(struct device *dev); + /** * hwmon_is_bad_char - Is the char invalid in a hwmon name * @ch: the char to be considered