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linux/drivers/leds/leds-ktd2692.c
Arnd Bergmann cbe99c538d leds: ktd2692: avoid harmless maybe-uninitialized warning 
gcc gets confused about the control flow in ktd2692_parse_dt(), causing
it to warn about what seems like a potential bug:

drivers/leds/leds-ktd2692.c: In function 'ktd2692_probe':
drivers/leds/leds-ktd2692.c:244:15: error: '*((void *)&led_cfg+8)' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/leds/leds-ktd2692.c:225:7: error: 'led_cfg.flash_max_microamp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/leds/leds-ktd2692.c:232:3: error: 'led_cfg.movie_max_microamp' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The code is fine, and slightly reworking it in an equivalent way lets
gcc figure that out too, which gets rid of the warning.

Fixes: 77e7915b15 ("leds: ktd2692: Add missing of_node_put")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
2017-01-26 21:16:38 +01:00

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/*
* LED driver : leds-ktd2692.c
*
* Copyright (C) 2015 Samsung Electronics
* Ingi Kim <ingi2.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/delay.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/led-class-flash.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
/* Value related the movie mode */
#define KTD2692_MOVIE_MODE_CURRENT_LEVELS 16
#define KTD2692_MM_TO_FL_RATIO(x) ((x) / 3)
#define KTD2962_MM_MIN_CURR_THRESHOLD_SCALE 8
/* Value related the flash mode */
#define KTD2692_FLASH_MODE_TIMEOUT_LEVELS 8
#define KTD2692_FLASH_MODE_TIMEOUT_DISABLE 0
#define KTD2692_FLASH_MODE_CURR_PERCENT(x) (((x) * 16) / 100)
/* Macro for getting offset of flash timeout */
#define GET_TIMEOUT_OFFSET(timeout, step) ((timeout) / (step))
/* Base register address */
#define KTD2692_REG_LVP_BASE 0x00
#define KTD2692_REG_FLASH_TIMEOUT_BASE 0x20
#define KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE 0x40
#define KTD2692_REG_MOVIE_CURRENT_BASE 0x60
#define KTD2692_REG_FLASH_CURRENT_BASE 0x80
#define KTD2692_REG_MODE_BASE 0xA0
/* Set bit coding time for expresswire interface */
#define KTD2692_TIME_RESET_US 700
#define KTD2692_TIME_DATA_START_TIME_US 10
#define KTD2692_TIME_HIGH_END_OF_DATA_US 350
#define KTD2692_TIME_LOW_END_OF_DATA_US 10
#define KTD2692_TIME_SHORT_BITSET_US 4
#define KTD2692_TIME_LONG_BITSET_US 12
/* KTD2692 default length of name */
#define KTD2692_NAME_LENGTH 20
enum ktd2692_bitset {
KTD2692_LOW = 0,
KTD2692_HIGH,
};
/* Movie / Flash Mode Control */
enum ktd2692_led_mode {
KTD2692_MODE_DISABLE = 0, /* default */
KTD2692_MODE_MOVIE,
KTD2692_MODE_FLASH,
};
struct ktd2692_led_config_data {
/* maximum LED current in movie mode */
u32 movie_max_microamp;
/* maximum LED current in flash mode */
u32 flash_max_microamp;
/* maximum flash timeout */
u32 flash_max_timeout;
/* max LED brightness level */
enum led_brightness max_brightness;
};
struct ktd2692_context {
/* Related LED Flash class device */
struct led_classdev_flash fled_cdev;
/* secures access to the device */
struct mutex lock;
struct regulator *regulator;
struct gpio_desc *aux_gpio;
struct gpio_desc *ctrl_gpio;
enum ktd2692_led_mode mode;
enum led_brightness torch_brightness;
};
static struct ktd2692_context *fled_cdev_to_led(
struct led_classdev_flash *fled_cdev)
{
return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
}
static void ktd2692_expresswire_start(struct ktd2692_context *led)
{
gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
udelay(KTD2692_TIME_DATA_START_TIME_US);
}
static void ktd2692_expresswire_reset(struct ktd2692_context *led)
{
gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
udelay(KTD2692_TIME_RESET_US);
}
static void ktd2692_expresswire_end(struct ktd2692_context *led)
{
gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
}
static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
{
/*
* The Low Bit(0) and High Bit(1) is based on a time detection
* algorithm between time low and time high
* Time_(L_LB) : Low time of the Low Bit(0)
* Time_(H_LB) : High time of the LOW Bit(0)
* Time_(L_HB) : Low time of the High Bit(1)
* Time_(H_HB) : High time of the High Bit(1)
*
* It can be simplified to:
* Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
* High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
* HIGH ___ ____ _.. _________ ___
* |_________| |_.. |____| |__|
* LOW <L_LB> <H_LB> <L_HB> <H_HB>
* [ Low Bit (0) ] [ High Bit(1) ]
*/
if (bit) {
gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
udelay(KTD2692_TIME_SHORT_BITSET_US);
gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
udelay(KTD2692_TIME_LONG_BITSET_US);
} else {
gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
udelay(KTD2692_TIME_LONG_BITSET_US);
gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
udelay(KTD2692_TIME_SHORT_BITSET_US);
}
}
static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
{
int i;
ktd2692_expresswire_start(led);
for (i = 7; i >= 0; i--)
ktd2692_expresswire_set_bit(led, value & BIT(i));
ktd2692_expresswire_end(led);
}
static int ktd2692_led_brightness_set(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
mutex_lock(&led->lock);
if (brightness == LED_OFF) {
led->mode = KTD2692_MODE_DISABLE;
gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
} else {
ktd2692_expresswire_write(led, brightness |
KTD2692_REG_MOVIE_CURRENT_BASE);
led->mode = KTD2692_MODE_MOVIE;
}
ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
mutex_unlock(&led->lock);
return 0;
}
static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
bool state)
{
struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
struct led_flash_setting *timeout = &fled_cdev->timeout;
u32 flash_tm_reg;
mutex_lock(&led->lock);
if (state) {
flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
ktd2692_expresswire_write(led, flash_tm_reg
| KTD2692_REG_FLASH_TIMEOUT_BASE);
led->mode = KTD2692_MODE_FLASH;
gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
} else {
led->mode = KTD2692_MODE_DISABLE;
gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
}
ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
fled_cdev->led_cdev.brightness = LED_OFF;
led->mode = KTD2692_MODE_DISABLE;
mutex_unlock(&led->lock);
return 0;
}
static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
u32 timeout)
{
return 0;
}
static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
{
u32 offset, step;
u32 movie_current_microamp;
offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
/ KTD2692_MOVIE_MODE_CURRENT_LEVELS;
do {
movie_current_microamp = step * offset;
offset--;
} while ((movie_current_microamp > cfg->movie_max_microamp) &&
(offset > 0));
cfg->max_brightness = offset;
}
static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
struct ktd2692_led_config_data *cfg)
{
struct led_flash_setting *setting;
setting = &fled_cdev->timeout;
setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
setting->max = cfg->flash_max_timeout;
setting->step = cfg->flash_max_timeout
/ (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
setting->val = cfg->flash_max_timeout;
}
static void ktd2692_setup(struct ktd2692_context *led)
{
led->mode = KTD2692_MODE_DISABLE;
ktd2692_expresswire_reset(led);
gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
ktd2692_expresswire_write(led, (KTD2962_MM_MIN_CURR_THRESHOLD_SCALE - 1)
| KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
| KTD2692_REG_FLASH_CURRENT_BASE);
}
static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
struct ktd2692_led_config_data *cfg)
{
struct device_node *np = dev->of_node;
struct device_node *child_node;
int ret;
if (!dev->of_node)
return -ENXIO;
led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
if (ret) {
dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
return ret;
}
led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
ret = PTR_ERR_OR_ZERO(led->aux_gpio);
if (ret) {
dev_err(dev, "cannot get aux-gpios %d\n", ret);
return ret;
}
led->regulator = devm_regulator_get(dev, "vin");
if (IS_ERR(led->regulator))
led->regulator = NULL;
if (led->regulator) {
ret = regulator_enable(led->regulator);
if (ret)
dev_err(dev, "Failed to enable supply: %d\n", ret);
}
child_node = of_get_next_available_child(np, NULL);
if (!child_node) {
dev_err(dev, "No DT child node found for connected LED.\n");
return -EINVAL;
}
led->fled_cdev.led_cdev.name =
of_get_property(child_node, "label", NULL) ? : child_node->name;
ret = of_property_read_u32(child_node, "led-max-microamp",
&cfg->movie_max_microamp);
if (ret) {
dev_err(dev, "failed to parse led-max-microamp\n");
goto err_parse_dt;
}
ret = of_property_read_u32(child_node, "flash-max-microamp",
&cfg->flash_max_microamp);
if (ret) {
dev_err(dev, "failed to parse flash-max-microamp\n");
goto err_parse_dt;
}
ret = of_property_read_u32(child_node, "flash-max-timeout-us",
&cfg->flash_max_timeout);
if (ret) {
dev_err(dev, "failed to parse flash-max-timeout-us\n");
goto err_parse_dt;
}
err_parse_dt:
of_node_put(child_node);
return ret;
}
static const struct led_flash_ops flash_ops = {
.strobe_set = ktd2692_led_flash_strobe_set,
.timeout_set = ktd2692_led_flash_timeout_set,
};
static int ktd2692_probe(struct platform_device *pdev)
{
struct ktd2692_context *led;
struct led_classdev *led_cdev;
struct led_classdev_flash *fled_cdev;
struct ktd2692_led_config_data led_cfg;
int ret;
led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
if (!led)
return -ENOMEM;
fled_cdev = &led->fled_cdev;
led_cdev = &fled_cdev->led_cdev;
ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
if (ret)
return ret;
ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
ktd2692_init_movie_current_max(&led_cfg);
fled_cdev->ops = &flash_ops;
led_cdev->max_brightness = led_cfg.max_brightness;
led_cdev->brightness_set_blocking = ktd2692_led_brightness_set;
led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
mutex_init(&led->lock);
platform_set_drvdata(pdev, led);
ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
if (ret) {
dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
mutex_destroy(&led->lock);
return ret;
}
ktd2692_setup(led);
return 0;
}
static int ktd2692_remove(struct platform_device *pdev)
{
struct ktd2692_context *led = platform_get_drvdata(pdev);
int ret;
led_classdev_flash_unregister(&led->fled_cdev);
if (led->regulator) {
ret = regulator_disable(led->regulator);
if (ret)
dev_err(&pdev->dev,
"Failed to disable supply: %d\n", ret);
}
mutex_destroy(&led->lock);
return 0;
}
static const struct of_device_id ktd2692_match[] = {
{ .compatible = "kinetic,ktd2692", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, ktd2692_match);
static struct platform_driver ktd2692_driver = {
.driver = {
.name = "ktd2692",
.of_match_table = ktd2692_match,
},
.probe = ktd2692_probe,
.remove = ktd2692_remove,
};
module_platform_driver(ktd2692_driver);
MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
MODULE_LICENSE("GPL v2");
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