hwmon: (lm87) Restore original configuration register on removal

This means that if we have to start the monitor when probed, we also
stop it on removal.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/hwmon/lm87.c

@@ -199,6 +199,7 @@ struct lm87_data {
 	unsigned long last_updated; /* In jiffies */
 
 	u8 channel;		/* register value */
+	u8 config;		/* original register value */
 
 	u8 in[8];		/* register value */
 	u8 in_max[8];		/* register value */
@@ -832,6 +833,7 @@ static int lm87_probe(struct i2c_client *new_client,
 	sysfs_remove_group(&new_client->dev.kobj, &lm87_group);
 	sysfs_remove_group(&new_client->dev.kobj, &lm87_group_opt);
 exit_free:
+	lm87_write_value(new_client, LM87_REG_CONFIG, data->config);
 	kfree(data);
 exit:
 	return err;
@@ -840,12 +842,11 @@ static int lm87_probe(struct i2c_client *new_client,
 static void lm87_init_client(struct i2c_client *client)
 {
 	struct lm87_data *data = i2c_get_clientdata(client);
-	u8 config;
 
 	data->channel = lm87_read_value(client, LM87_REG_CHANNEL_MODE);
+	data->config = lm87_read_value(client, LM87_REG_CONFIG) & 0x6F;
 
-	config = lm87_read_value(client, LM87_REG_CONFIG);
-	if (!(config & 0x01)) {
+	if (!(data->config & 0x01)) {
 		int i;
 
 		/* Limits are left uninitialized after power-up */
@@ -869,9 +870,9 @@ static void lm87_init_client(struct i2c_client *client)
 	}
 
 	/* Make sure Start is set and INT#_Clear is clear */
-	if ((config & 0x09) != 0x01)
+	if ((data->config & 0x09) != 0x01)
 		lm87_write_value(client, LM87_REG_CONFIG,
-				 (config & 0x77) | 0x01);
+				 (data->config & 0x77) | 0x01);
 }
 
 static int lm87_remove(struct i2c_client *client)
@@ -882,6 +883,7 @@ static int lm87_remove(struct i2c_client *client)
 	sysfs_remove_group(&client->dev.kobj, &lm87_group);
 	sysfs_remove_group(&client->dev.kobj, &lm87_group_opt);
 
+	lm87_write_value(client, LM87_REG_CONFIG, data->config);
 	kfree(data);
 	return 0;
 }