leds: leds-is31fl32xx: merge modifies from develop-3.10.

1. fix cpu stall issue during reboot:
   In previous code, i2c write and read is executed in function
   is31fl32xx_brightness_set,this function may be called in softirq
   context if leds are in timer or oneshot trigger, so there are
   possibilities cpu will be stalled during led operations.
   Here we just move the i2c operation to workqueue to make sure
   not in irq context.
2. fix reboot crash issue.

Change-Id: If8520528b092cf4d5c4f1c7dcf2d353acd1c9b9d
Signed-off-by: Wenping Zhang <wenping.zhang@rock-chips.com>

Author: Wenping Zhang

drivers/leds/leds-is31fl32xx.c

@@ -20,6 +20,9 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/delay.h>
+#include <linux/of_gpio.h>
+#include <linux/gpio.h>
 
 /* Used to indicate a device has no such register */
 #define IS31FL32XX_REG_NONE 0xFF
@@ -45,12 +48,16 @@ struct is31fl32xx_led_data {
 	unsigned int register_delay;
 	struct device *dev;
 	struct delayed_work register_work;
+	struct work_struct brightness_work;
+	enum led_brightness new_brightness;
 };
 
 struct is31fl32xx_priv {
 	const struct is31fl32xx_chipdef *cdef;
 	struct i2c_client *client;
 	unsigned int num_leds;
+	struct mutex led_mutex;
+	struct gpio_desc *reset_gpio;
 	struct is31fl32xx_led_data leds[0];
 };
 
@@ -205,6 +212,33 @@ static int is31fl3216_software_shutdown(struct is31fl32xx_priv *priv,
 	return is31fl32xx_write(priv, IS31FL3216_CONFIG_REG, value);
 }
 
+static void is31fl32xx_brightness_work(struct work_struct *work)
+{
+	const struct is31fl32xx_led_data *led_data =
+			container_of(work,
+				     struct is31fl32xx_led_data,
+				     brightness_work);
+	const struct is31fl32xx_chipdef *cdef = led_data->priv->cdef;
+	u8 pwm_register_offset;
+	int ret;
+
+	dev_dbg(led_data->cdev.dev, "%s: %d\n",
+		__func__, led_data->new_brightness);
+	mutex_lock(&led_data->priv->led_mutex);
+	/* NOTE: led_data->channel is 1-based */
+	if (cdef->pwm_registers_reversed)
+		pwm_register_offset = cdef->channels - led_data->channel;
+	else
+		pwm_register_offset = led_data->channel - 1;
+
+	ret = is31fl32xx_write(led_data->priv,
+			       cdef->pwm_register_base + pwm_register_offset,
+			       led_data->new_brightness);
+
+	is31fl32xx_write(led_data->priv, cdef->pwm_update_reg, 0);
+	mutex_unlock(&led_data->priv->led_mutex);
+}
+
 /*
  * NOTE: A mutex is not needed in this function because:
  * - All referenced data is read-only after probe()
@@ -229,29 +263,11 @@ static int is31fl3216_software_shutdown(struct is31fl32xx_priv *priv,
 static void is31fl32xx_brightness_set(struct led_classdev *led_cdev,
 				     enum led_brightness brightness)
 {
-	const struct is31fl32xx_led_data *led_data =
+	struct is31fl32xx_led_data *led_data =
 		container_of(led_cdev, struct is31fl32xx_led_data, cdev);
-	const struct is31fl32xx_chipdef *cdef = led_data->priv->cdef;
-	u8 pwm_register_offset;
-	int ret;
-
-	dev_dbg(led_cdev->dev, "%s: %d\n", __func__, brightness);
-
-	/* NOTE: led_data->channel is 1-based */
-	if (cdef->pwm_registers_reversed)
-		pwm_register_offset = cdef->channels - led_data->channel;
-	else
-		pwm_register_offset = led_data->channel - 1;
-
-	ret = is31fl32xx_write(led_data->priv,
-			       cdef->pwm_register_base + pwm_register_offset,
-			       brightness);
-	if (ret)
-		dev_err(led_cdev->dev,
-			"set brightness %d for led[%d] failed\n",
-			brightness, pwm_register_offset);
 
-	is31fl32xx_write(led_data->priv, cdef->pwm_update_reg, 0);
+	led_data->new_brightness = brightness;
+	schedule_work(&led_data->brightness_work);
 }
 
 static int is31fl32xx_reset_regs(struct is31fl32xx_priv *priv)
@@ -298,7 +314,7 @@ static int is31fl32xx_init_regs(struct is31fl32xx_priv *priv)
 
 	ret = is31fl32xx_reset_regs(priv);
 	if (ret)
-		return ret;
+		pr_err("%s, write to reset register failed\n", __func__);
 
 	/*
 	 * Set enable bit for all channels.
@@ -377,6 +393,7 @@ static int is31fl32xx_parse_child_dt(const struct device *dev,
 
 	cdev->brightness_set = is31fl32xx_brightness_set;
 
+	INIT_WORK(&led_data->brightness_work, is31fl32xx_brightness_work);
 	return 0;
 }
 
@@ -482,24 +499,39 @@ static int is31fl32xx_probe(struct i2c_client *client,
 	struct is31fl32xx_priv *priv;
 	int count;
 	int ret = 0;
+	struct gpio_desc *gpio;
 
 	of_dev_id = of_match_device(of_is31fl32xx_match, dev);
 	if (!of_dev_id)
 		return -EINVAL;
 
+	gpio = devm_gpiod_get_optional(dev,
+				       "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(gpio)) {
+		int error = PTR_ERR(gpio);
+
+		dev_err(dev, "Failed to get reset gpio: %d\n", error);
+		return -EINVAL;
+	}
+	gpiod_direction_output(gpio, 1);
+
 	cdef = of_dev_id->data;
 
 	count = of_get_child_count(dev->of_node);
-	if (!count)
+	if (!count) {
+		dev_err(dev, "count is invalid\n");
 		return -EINVAL;
+	}
 
 	priv = devm_kzalloc(dev, sizeof_is31fl32xx_priv(count),
 			    GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
+	mutex_init(&priv->led_mutex);
 	priv->client = client;
 	priv->cdef = cdef;
+	priv->reset_gpio = gpio;
 	i2c_set_clientdata(client, priv);
 
 	ret = is31fl32xx_init_regs(priv);
@@ -515,11 +547,35 @@ static int is31fl32xx_probe(struct i2c_client *client,
 
 static int is31fl32xx_remove(struct i2c_client *client)
 {
+	int i;
 	struct is31fl32xx_priv *priv = i2c_get_clientdata(client);
 
+	for (i = 0; i < priv->num_leds; i++) {
+		struct is31fl32xx_led_data *led_data =
+					&priv->leds[i];
+		cancel_delayed_work_sync(&led_data->register_work);
+		cancel_work_sync(&led_data->brightness_work);
+	}
+
 	return is31fl32xx_reset_regs(priv);
 }
 
+static void is31fl32xx_shutdown(struct i2c_client *client)
+{
+	int i;
+	struct is31fl32xx_priv *priv = i2c_get_clientdata(client);
+
+	for (i = 0; i < priv->num_leds; i++) {
+		struct is31fl32xx_led_data *led_data =
+					&priv->leds[i];
+		cancel_delayed_work_sync(&led_data->register_work);
+		cancel_work_sync(&led_data->brightness_work);
+	}
+
+	is31fl32xx_reset_regs(priv);
+	gpiod_set_value(priv->reset_gpio, 0);
+}
+
 /*
  * i2c-core (and modalias) requires that id_table be properly filled,
  * even though it is not used for DeviceTree based instantiation.
@@ -543,6 +599,7 @@ static struct i2c_driver is31fl32xx_driver = {
 	},
 	.probe		= is31fl32xx_probe,
 	.remove		= is31fl32xx_remove,
+	.shutdown	= is31fl32xx_shutdown,
 	.id_table	= is31fl32xx_id,
 };