[PATCH 15/29] hwmon: (aht10) Rely on subsystem locking

[Guenter Roeck <linux@roeck-us.net>]

Attribute access is now serialized in the hardware monitoring core,
so locking in the driver code is no longer necessary. Drop it.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/aht10.c | 24 +++---------------------
 1 file changed, 3 insertions(+), 21 deletions(-)

diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c
index d1c55e2eb479..8b90b661c393 100644
--- a/drivers/hwmon/aht10.c
+++ b/drivers/hwmon/aht10.c
@@ -60,8 +60,6 @@ MODULE_DEVICE_TABLE(i2c, aht10_id);
 /**
  *   struct aht10_data - All the data required to operate an AHT10/AHT20 chip
  *   @client: the i2c client associated with the AHT10/AHT20
- *   @lock: a mutex that is used to prevent parallel access to the
- *          i2c client
  *   @min_poll_interval: the minimum poll interval
  *                   While the poll rate limit is not 100% necessary,
  *                   the datasheet recommends that a measurement
@@ -81,11 +79,6 @@ MODULE_DEVICE_TABLE(i2c, aht10_id);
 
 struct aht10_data {
 	struct i2c_client *client;
-	/*
-	 * Prevent simultaneous access to the i2c
-	 * client and previous_poll_time
-	 */
-	struct mutex lock;
 	ktime_t min_poll_interval;
 	ktime_t previous_poll_time;
 	int temperature;
@@ -168,32 +161,24 @@ static int aht10_read_values(struct aht10_data *data)
 	u8 raw_data[AHT20_MEAS_SIZE];
 	struct i2c_client *client = data->client;
 
-	mutex_lock(&data->lock);
-	if (!aht10_polltime_expired(data)) {
-		mutex_unlock(&data->lock);
+	if (!aht10_polltime_expired(data))
 		return 0;
-	}
 
 	res = i2c_master_send(client, cmd_meas, sizeof(cmd_meas));
-	if (res < 0) {
-		mutex_unlock(&data->lock);
+	if (res < 0)
 		return res;
-	}
 
 	usleep_range(AHT10_MEAS_DELAY, AHT10_MEAS_DELAY + AHT10_DELAY_EXTRA);
 
 	res = i2c_master_recv(client, raw_data, data->meas_size);
 	if (res != data->meas_size) {
-		mutex_unlock(&data->lock);
 		if (res >= 0)
 			return -ENODATA;
 		return res;
 	}
 
-	if (data->crc8 && crc8_check(raw_data, data->meas_size)) {
-		mutex_unlock(&data->lock);
+	if (data->crc8 && crc8_check(raw_data, data->meas_size))
 		return -EIO;
-	}
 
 	hum =   ((u32)raw_data[1] << 12u) |
 		((u32)raw_data[2] << 4u) |
@@ -210,7 +195,6 @@ static int aht10_read_values(struct aht10_data *data)
 	data->humidity = hum;
 	data->previous_poll_time = ktime_get_boottime();
 
-	mutex_unlock(&data->lock);
 	return 0;
 }
 
@@ -358,8 +342,6 @@ static int aht10_probe(struct i2c_client *client)
 		break;
 	}
 
-	mutex_init(&data->lock);
-
 	res = aht10_init(data);
 	if (res < 0)
 		return res;
-- 
2.45.2