From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-path: From: Nicolin Chen To: jdelvare@suse.com, linux@roeck-us.net Cc: linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/5] hwmon: (ina3221) Serialize sysfs ABI accesses Date: Tue, 16 Oct 2018 18:24:24 -0700 Message-Id: <20181017012426.26958-4-nicoleotsuka@gmail.com> In-Reply-To: <20181017012426.26958-1-nicoleotsuka@gmail.com> References: <20181017012426.26958-1-nicoleotsuka@gmail.com> List-ID: This change adds a mutex to serialize accesses of sysfs attributes. This is required when polling CVRF bit of the MASK/ENABLE register because this bit is cleared on a read of this MASK/ENABLE register or a write to CONFIG register, which means that this bit might be accidentally cleared by reading other fields like alert flags. So this patch adds a mutex lock to protect the write() and read() callbacks. The read_string() callback won't need the lock since it just returns the label without touching any hardware register. Signed-off-by: Nicolin Chen --- drivers/hwmon/ina3221.c | 51 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 45 insertions(+), 6 deletions(-) diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c index 3e98b59108ee..5fc375bf6635 100644 --- a/drivers/hwmon/ina3221.c +++ b/drivers/hwmon/ina3221.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -94,12 +95,14 @@ struct ina3221_input { * @regmap: Register map of the device * @fields: Register fields of the device * @inputs: Array of channel input source specific structures + * @lock: mutex lock to serialize sysfs attribute accesses * @reg_config: Register value of INA3221_CONFIG */ struct ina3221_data { struct regmap *regmap; struct regmap_field *fields[F_MAX_FIELDS]; struct ina3221_input inputs[INA3221_NUM_CHANNELS]; + struct mutex lock; u32 reg_config; }; @@ -261,29 +264,53 @@ static int ina3221_write_enable(struct device *dev, int channel, bool enable) static int ina3221_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) { + struct ina3221_data *ina = dev_get_drvdata(dev); + int ret; + + mutex_lock(&ina->lock); + switch (type) { case hwmon_in: /* 0-align channel ID */ - return ina3221_read_in(dev, attr, channel - 1, val); + ret = ina3221_read_in(dev, attr, channel - 1, val); + break; case hwmon_curr: - return ina3221_read_curr(dev, attr, channel, val); + ret = ina3221_read_curr(dev, attr, channel, val); + break; default: - return -EOPNOTSUPP; + ret = -EOPNOTSUPP; + break; } + + mutex_unlock(&ina->lock); + + return ret; } static int ina3221_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) { + struct ina3221_data *ina = dev_get_drvdata(dev); + int ret; + + mutex_lock(&ina->lock); + switch (type) { case hwmon_in: /* 0-align channel ID */ - return ina3221_write_enable(dev, channel - 1, val); + ret = ina3221_write_enable(dev, channel - 1, val); + break; case hwmon_curr: - return ina3221_write_curr(dev, attr, channel, val); + ret = ina3221_write_curr(dev, attr, channel, val); + break; default: - return -EOPNOTSUPP; + ret = -EOPNOTSUPP; + break; } + + mutex_unlock(&ina->lock); + + return ret; } static int ina3221_read_string(struct device *dev, enum hwmon_sensor_types type, @@ -578,6 +605,7 @@ static int ina3221_probe(struct i2c_client *client, if (ret) return ret; + mutex_init(&ina->lock); dev_set_drvdata(dev, ina); hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, ina, @@ -585,12 +613,22 @@ static int ina3221_probe(struct i2c_client *client, ina3221_groups); if (IS_ERR(hwmon_dev)) { dev_err(dev, "Unable to register hwmon device\n"); + mutex_destroy(&ina->lock); return PTR_ERR(hwmon_dev); } return 0; } +static int ina3221_remove(struct i2c_client *client) +{ + struct ina3221_data *ina = dev_get_drvdata(&client->dev); + + mutex_destroy(&ina->lock); + + return 0; +} + static int __maybe_unused ina3221_suspend(struct device *dev) { struct ina3221_data *ina = dev_get_drvdata(dev); @@ -659,6 +697,7 @@ MODULE_DEVICE_TABLE(i2c, ina3221_ids); static struct i2c_driver ina3221_i2c_driver = { .probe = ina3221_probe, + .remove = ina3221_remove, .driver = { .name = INA3221_DRIVER_NAME, .of_match_table = ina3221_of_match_table, -- 2.17.1