hwmon: (nct7904) Rely on subsystem locking

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>

diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
index f1e6eda949ba237345f5e560d20ec118a8ff2125..2fa091720c79b1c66bd181290414f08c1e2c2da2 100644 (file)
--- a/drivers/hwmon/nct7904.c
+++ b/drivers/hwmon/nct7904.c
@@ -21,7 +21,6 @@
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
-#include <linux/mutex.h>
 #include <linux/hwmon.h>
 #include <linux/watchdog.h>
 
@@ -128,7 +127,6 @@ static const unsigned short normal_i2c[] = {
 struct nct7904_data {
        struct i2c_client *client;
        struct watchdog_device wdt;
-       struct mutex bank_lock;
        int bank_sel;
        u32 fanin_mask;
        u32 vsen_mask;
@@ -142,24 +140,19 @@ struct nct7904_data {
 };
 
 /* Access functions */
-static int nct7904_bank_lock(struct nct7904_data *data, unsigned int bank)
+static int nct7904_bank_select(struct nct7904_data *data, unsigned int bank)
 {
        int ret;
 
-       mutex_lock(&data->bank_lock);
        if (data->bank_sel == bank)
                return 0;
        ret = i2c_smbus_write_byte_data(data->client, BANK_SEL_REG, bank);
-       if (ret == 0)
-               data->bank_sel = bank;
-       else
+       if (ret < 0) {
                data->bank_sel = -1;
-       return ret;
-}
-
-static inline void nct7904_bank_release(struct nct7904_data *data)
-{
-       mutex_unlock(&data->bank_lock);
+               return ret;
+       }
+       data->bank_sel = bank;
+       return 0;
 }
 
 /* Read 1-byte register. Returns unsigned reg or -ERRNO on error. */
@@ -169,12 +162,10 @@ static int nct7904_read_reg(struct nct7904_data *data,
        struct i2c_client *client = data->client;
        int ret;
 
-       ret = nct7904_bank_lock(data, bank);
-       if (ret == 0)
-               ret = i2c_smbus_read_byte_data(client, reg);
-
-       nct7904_bank_release(data);
-       return ret;
+       ret = nct7904_bank_select(data, bank);
+       if (ret < 0)
+               return ret;
+       return i2c_smbus_read_byte_data(client, reg);
 }
 
 /*
@@ -187,19 +178,16 @@ static int nct7904_read_reg16(struct nct7904_data *data,
        struct i2c_client *client = data->client;
        int ret, hi;
 
-       ret = nct7904_bank_lock(data, bank);
-       if (ret == 0) {
-               ret = i2c_smbus_read_byte_data(client, reg);
-               if (ret >= 0) {
-                       hi = ret;
-                       ret = i2c_smbus_read_byte_data(client, reg + 1);
-                       if (ret >= 0)
-                               ret |= hi << 8;
-               }
-       }
-
-       nct7904_bank_release(data);
-       return ret;
+       ret = nct7904_bank_select(data, bank);
+       if (ret < 0)
+               return ret;
+       hi = i2c_smbus_read_byte_data(client, reg);
+       if (hi < 0)
+               return hi;
+       ret = i2c_smbus_read_byte_data(client, reg + 1);
+       if (ret < 0)
+               return ret;
+       return ret | (hi << 8);
 }
 
 /* Write 1-byte register. Returns 0 or -ERRNO on error. */
@@ -209,12 +197,10 @@ static int nct7904_write_reg(struct nct7904_data *data,
        struct i2c_client *client = data->client;
        int ret;
 
-       ret = nct7904_bank_lock(data, bank);
-       if (ret == 0)
-               ret = i2c_smbus_write_byte_data(client, reg, val);
-
-       nct7904_bank_release(data);
-       return ret;
+       ret = nct7904_bank_select(data, bank);
+       if (ret < 0)
+               return ret;
+       return i2c_smbus_write_byte_data(client, reg, val);
 }
 
 static int nct7904_read_fan(struct device *dev, u32 attr, int channel,
@@ -1023,7 +1009,6 @@ static int nct7904_probe(struct i2c_client *client)
                return -ENOMEM;
 
        data->client = client;
-       mutex_init(&data->bank_lock);
        data->bank_sel = -1;
 
        /* Setup sensor groups. */