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linux/drivers/leds/leds-max8997.c
Johan Hovold 35c164998e leds: max8997: fix attribute-creation race 
Use the attribute groups of the led-class to create the mode attribute
during probe in order to avoid racing with userspace.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-06-25 15:24:03 -07:00

318 lines
7.9 KiB
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/*
* leds-max8997.c - LED class driver for MAX8997 LEDs.
*
* Copyright (C) 2011 Samsung Electronics
* Donggeun Kim <dg77.kim@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/leds.h>
#include <linux/mfd/max8997.h>
#include <linux/mfd/max8997-private.h>
#include <linux/platform_device.h>
#define MAX8997_LED_FLASH_SHIFT 3
#define MAX8997_LED_FLASH_CUR_MASK 0xf8
#define MAX8997_LED_MOVIE_SHIFT 4
#define MAX8997_LED_MOVIE_CUR_MASK 0xf0
#define MAX8997_LED_FLASH_MAX_BRIGHTNESS 0x1f
#define MAX8997_LED_MOVIE_MAX_BRIGHTNESS 0xf
#define MAX8997_LED_NONE_MAX_BRIGHTNESS 0
#define MAX8997_LED0_FLASH_MASK 0x1
#define MAX8997_LED0_FLASH_PIN_MASK 0x5
#define MAX8997_LED0_MOVIE_MASK 0x8
#define MAX8997_LED0_MOVIE_PIN_MASK 0x28
#define MAX8997_LED1_FLASH_MASK 0x2
#define MAX8997_LED1_FLASH_PIN_MASK 0x6
#define MAX8997_LED1_MOVIE_MASK 0x10
#define MAX8997_LED1_MOVIE_PIN_MASK 0x30
#define MAX8997_LED_BOOST_ENABLE_MASK (1 << 6)
struct max8997_led {
struct max8997_dev *iodev;
struct led_classdev cdev;
bool enabled;
int id;
enum max8997_led_mode led_mode;
struct mutex mutex;
};
static void max8997_led_set_mode(struct max8997_led *led,
enum max8997_led_mode mode)
{
int ret;
struct i2c_client *client = led->iodev->i2c;
u8 mask = 0, val;
switch (mode) {
case MAX8997_FLASH_MODE:
mask = MAX8997_LED1_FLASH_MASK | MAX8997_LED0_FLASH_MASK;
val = led->id ?
MAX8997_LED1_FLASH_MASK : MAX8997_LED0_FLASH_MASK;
led->cdev.max_brightness = MAX8997_LED_FLASH_MAX_BRIGHTNESS;
break;
case MAX8997_MOVIE_MODE:
mask = MAX8997_LED1_MOVIE_MASK | MAX8997_LED0_MOVIE_MASK;
val = led->id ?
MAX8997_LED1_MOVIE_MASK : MAX8997_LED0_MOVIE_MASK;
led->cdev.max_brightness = MAX8997_LED_MOVIE_MAX_BRIGHTNESS;
break;
case MAX8997_FLASH_PIN_CONTROL_MODE:
mask = MAX8997_LED1_FLASH_PIN_MASK |
MAX8997_LED0_FLASH_PIN_MASK;
val = led->id ?
MAX8997_LED1_FLASH_PIN_MASK : MAX8997_LED0_FLASH_PIN_MASK;
led->cdev.max_brightness = MAX8997_LED_FLASH_MAX_BRIGHTNESS;
break;
case MAX8997_MOVIE_PIN_CONTROL_MODE:
mask = MAX8997_LED1_MOVIE_PIN_MASK |
MAX8997_LED0_MOVIE_PIN_MASK;
val = led->id ?
MAX8997_LED1_MOVIE_PIN_MASK : MAX8997_LED0_MOVIE_PIN_MASK;
led->cdev.max_brightness = MAX8997_LED_MOVIE_MAX_BRIGHTNESS;
break;
default:
led->cdev.max_brightness = MAX8997_LED_NONE_MAX_BRIGHTNESS;
break;
}
if (mask) {
ret = max8997_update_reg(client, MAX8997_REG_LEN_CNTL, val,
mask);
if (ret)
dev_err(led->iodev->dev,
"failed to update register(%d)\n", ret);
}
led->led_mode = mode;
}
static void max8997_led_enable(struct max8997_led *led, bool enable)
{
int ret;
struct i2c_client *client = led->iodev->i2c;
u8 val = 0, mask = MAX8997_LED_BOOST_ENABLE_MASK;
if (led->enabled == enable)
return;
val = enable ? MAX8997_LED_BOOST_ENABLE_MASK : 0;
ret = max8997_update_reg(client, MAX8997_REG_BOOST_CNTL, val, mask);
if (ret)
dev_err(led->iodev->dev,
"failed to update register(%d)\n", ret);
led->enabled = enable;
}
static void max8997_led_set_current(struct max8997_led *led,
enum led_brightness value)
{
int ret;
struct i2c_client *client = led->iodev->i2c;
u8 val = 0, mask = 0, reg = 0;
switch (led->led_mode) {
case MAX8997_FLASH_MODE:
case MAX8997_FLASH_PIN_CONTROL_MODE:
val = value << MAX8997_LED_FLASH_SHIFT;
mask = MAX8997_LED_FLASH_CUR_MASK;
reg = led->id ? MAX8997_REG_FLASH2_CUR : MAX8997_REG_FLASH1_CUR;
break;
case MAX8997_MOVIE_MODE:
case MAX8997_MOVIE_PIN_CONTROL_MODE:
val = value << MAX8997_LED_MOVIE_SHIFT;
mask = MAX8997_LED_MOVIE_CUR_MASK;
reg = MAX8997_REG_MOVIE_CUR;
break;
default:
break;
}
if (mask) {
ret = max8997_update_reg(client, reg, val, mask);
if (ret)
dev_err(led->iodev->dev,
"failed to update register(%d)\n", ret);
}
}
static void max8997_led_brightness_set(struct led_classdev *led_cdev,
enum led_brightness value)
{
struct max8997_led *led =
container_of(led_cdev, struct max8997_led, cdev);
if (value) {
max8997_led_set_current(led, value);
max8997_led_enable(led, true);
} else {
max8997_led_set_current(led, value);
max8997_led_enable(led, false);
}
}
static ssize_t max8997_led_show_mode(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
struct max8997_led *led =
container_of(led_cdev, struct max8997_led, cdev);
ssize_t ret = 0;
mutex_lock(&led->mutex);
switch (led->led_mode) {
case MAX8997_FLASH_MODE:
ret += sprintf(buf, "FLASH\n");
break;
case MAX8997_MOVIE_MODE:
ret += sprintf(buf, "MOVIE\n");
break;
case MAX8997_FLASH_PIN_CONTROL_MODE:
ret += sprintf(buf, "FLASH_PIN_CONTROL\n");
break;
case MAX8997_MOVIE_PIN_CONTROL_MODE:
ret += sprintf(buf, "MOVIE_PIN_CONTROL\n");
break;
default:
ret += sprintf(buf, "NONE\n");
break;
}
mutex_unlock(&led->mutex);
return ret;
}
static ssize_t max8997_led_store_mode(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
struct max8997_led *led =
container_of(led_cdev, struct max8997_led, cdev);
enum max8997_led_mode mode;
mutex_lock(&led->mutex);
if (!strncmp(buf, "FLASH_PIN_CONTROL", 17))
mode = MAX8997_FLASH_PIN_CONTROL_MODE;
else if (!strncmp(buf, "MOVIE_PIN_CONTROL", 17))
mode = MAX8997_MOVIE_PIN_CONTROL_MODE;
else if (!strncmp(buf, "FLASH", 5))
mode = MAX8997_FLASH_MODE;
else if (!strncmp(buf, "MOVIE", 5))
mode = MAX8997_MOVIE_MODE;
else
mode = MAX8997_NONE;
max8997_led_set_mode(led, mode);
mutex_unlock(&led->mutex);
return size;
}
static DEVICE_ATTR(mode, 0644, max8997_led_show_mode, max8997_led_store_mode);
static struct attribute *max8997_attrs[] = {
&dev_attr_mode.attr,
NULL
};
ATTRIBUTE_GROUPS(max8997);
static int max8997_led_probe(struct platform_device *pdev)
{
struct max8997_dev *iodev = dev_get_drvdata(pdev->dev.parent);
struct max8997_platform_data *pdata = dev_get_platdata(iodev->dev);
struct max8997_led *led;
char name[20];
int ret = 0;
if (pdata == NULL) {
dev_err(&pdev->dev, "no platform data\n");
return -ENODEV;
}
led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
if (led == NULL)
return -ENOMEM;
led->id = pdev->id;
snprintf(name, sizeof(name), "max8997-led%d", pdev->id);
led->cdev.name = name;
led->cdev.brightness_set = max8997_led_brightness_set;
led->cdev.flags |= LED_CORE_SUSPENDRESUME;
led->cdev.brightness = 0;
led->cdev.groups = max8997_groups;
led->iodev = iodev;
/* initialize mode and brightness according to platform_data */
if (pdata->led_pdata) {
u8 mode = 0, brightness = 0;
mode = pdata->led_pdata->mode[led->id];
brightness = pdata->led_pdata->brightness[led->id];
max8997_led_set_mode(led, pdata->led_pdata->mode[led->id]);
if (brightness > led->cdev.max_brightness)
brightness = led->cdev.max_brightness;
max8997_led_set_current(led, brightness);
led->cdev.brightness = brightness;
} else {
max8997_led_set_mode(led, MAX8997_NONE);
max8997_led_set_current(led, 0);
}
mutex_init(&led->mutex);
platform_set_drvdata(pdev, led);
ret = led_classdev_register(&pdev->dev, &led->cdev);
if (ret < 0)
return ret;
return 0;
}
static int max8997_led_remove(struct platform_device *pdev)
{
struct max8997_led *led = platform_get_drvdata(pdev);
led_classdev_unregister(&led->cdev);
return 0;
}
static struct platform_driver max8997_led_driver = {
.driver = {
.name = "max8997-led",
.owner = THIS_MODULE,
},
.probe = max8997_led_probe,
.remove = max8997_led_remove,
};
module_platform_driver(max8997_led_driver);
MODULE_AUTHOR("Donggeun Kim <dg77.kim@samsung.com>");
MODULE_DESCRIPTION("MAX8997 LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:max8997-led");
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