leds: lp5521: fix circular locking

Driver contained possibility for circular locking.

One lock is held by sysfs-core and another one by the driver itself.  This
happened when the driver created or removed sysfs entries dynamically.
There is no real need to do those operations.  Now all the sysfs entries
are created at probe and removed at removal.  Engine load sysfs entries
are now visible all the time.  However, access to the entries fails if the
engine is disabled or running.
Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Cc: Arun Murthy <arun.murthy@stericsson.com>
Reviewed-by: Ilkka Koskinen <ilkka.koskinen@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/leds/leds-lp5521.c

@@ -98,7 +98,6 @@
 #define LP5521_EXT_CLK_USED		0x08
 
 struct lp5521_engine {
-	const struct attribute_group *attributes;
 	int		id;
 	u8		mode;
 	u8		prog_page;
@@ -225,25 +224,22 @@ static int lp5521_set_led_current(struct lp5521_chip *chip, int led, u8 curr)
 		    curr);
 }
 
-static void lp5521_init_engine(struct lp5521_chip *chip,
-			const struct attribute_group *attr_group)
+static void lp5521_init_engine(struct lp5521_chip *chip)
 {
 	int i;
 	for (i = 0; i < ARRAY_SIZE(chip->engines); i++) {
 		chip->engines[i].id = i + 1;
 		chip->engines[i].engine_mask = LP5521_ENG_MASK_BASE >> (i * 2);
 		chip->engines[i].prog_page = i;
-		chip->engines[i].attributes = &attr_group[i];
 	}
 }
 
-static int lp5521_configure(struct i2c_client *client,
-			const struct attribute_group *attr_group)
+static int lp5521_configure(struct i2c_client *client)
 {
 	struct lp5521_chip *chip = i2c_get_clientdata(client);
 	int ret;
 
-	lp5521_init_engine(chip, attr_group);
+	lp5521_init_engine(chip);
 
 	/* Set all PWMs to direct control mode */
 	ret = lp5521_write(client, LP5521_REG_OP_MODE, 0x3F);
@@ -329,9 +325,6 @@ static int lp5521_detect(struct i2c_client *client)
 /* Set engine mode and create appropriate sysfs attributes, if required. */
 static int lp5521_set_mode(struct lp5521_engine *engine, u8 mode)
 {
-	struct lp5521_chip *chip = engine_to_lp5521(engine);
-	struct i2c_client *client = chip->client;
-	struct device *dev = &client->dev;
 	int ret = 0;
 
 	/* if in that mode already do nothing, except for run */
@@ -343,18 +336,10 @@ static int lp5521_set_mode(struct lp5521_engine *engine, u8 mode)
 	} else if (mode == LP5521_CMD_LOAD) {
 		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
 		lp5521_set_engine_mode(engine, LP5521_CMD_LOAD);
-
-		ret = sysfs_create_group(&dev->kobj, engine->attributes);
-		if (ret)
-			return ret;
 	} else if (mode == LP5521_CMD_DISABLED) {
 		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
 	}
 
-	/* remove load attribute from sysfs if not in load mode */
-	if (engine->mode == LP5521_CMD_LOAD && mode != LP5521_CMD_LOAD)
-		sysfs_remove_group(&dev->kobj, engine->attributes);
-
 	engine->mode = mode;
 
 	return ret;
@@ -389,7 +374,10 @@ static int lp5521_do_store_load(struct lp5521_engine *engine,
 		goto fail;
 
 	mutex_lock(&chip->lock);
-	ret = lp5521_load_program(engine, pattern);
+	if (engine->mode == LP5521_CMD_LOAD)
+		ret = lp5521_load_program(engine, pattern);
+	else
+		ret = -EINVAL;
 	mutex_unlock(&chip->lock);
 
 	if (ret) {
@@ -576,20 +564,8 @@ static struct attribute *lp5521_attributes[] = {
 	&dev_attr_engine2_mode.attr,
 	&dev_attr_engine3_mode.attr,
 	&dev_attr_selftest.attr,
-	NULL
-};
-
-static struct attribute *lp5521_engine1_attributes[] = {
 	&dev_attr_engine1_load.attr,
-	NULL
-};
-
-static struct attribute *lp5521_engine2_attributes[] = {
 	&dev_attr_engine2_load.attr,
-	NULL
-};
-
-static struct attribute *lp5521_engine3_attributes[] = {
 	&dev_attr_engine3_load.attr,
 	NULL
 };
@@ -598,12 +574,6 @@ static const struct attribute_group lp5521_group = {
 	.attrs = lp5521_attributes,
 };
 
-static const struct attribute_group lp5521_engine_group[] = {
-	{.attrs = lp5521_engine1_attributes },
-	{.attrs = lp5521_engine2_attributes },
-	{.attrs = lp5521_engine3_attributes },
-};
-
 static int lp5521_register_sysfs(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
@@ -618,12 +588,6 @@ static void lp5521_unregister_sysfs(struct i2c_client *client)
 
 	sysfs_remove_group(&dev->kobj, &lp5521_group);
 
-	for (i = 0; i <  ARRAY_SIZE(chip->engines); i++) {
-		if (chip->engines[i].mode == LP5521_CMD_LOAD)
-			sysfs_remove_group(&dev->kobj,
-					chip->engines[i].attributes);
-	}
-
 	for (i = 0; i < chip->num_leds; i++)
 		sysfs_remove_group(&chip->leds[i].cdev.dev->kobj,
 				&lp5521_led_attribute_group);
@@ -725,7 +689,7 @@ static int lp5521_probe(struct i2c_client *client,
 
 	dev_info(&client->dev, "%s programmable led chip found\n", id->name);
 
-	ret = lp5521_configure(client, lp5521_engine_group);
+	ret = lp5521_configure(client);
 	if (ret < 0) {
 		dev_err(&client->dev, "error configuring chip\n");
 		goto fail2;