nuc970添加led heartbeat - GPIOI2

 

Linux 驱动的注册过程：

 

https://www.cnblogs.com/haimeng2010/p/3582403.html

 

通过 Platform 机制开发发底层驱动的大致流程为: 定义platform_add_devices --> 注册platform_device --> 定义platform_add_driver --> 注册platform_driver 。

platform_device 和 platform_driver 通过.name 关联， 名字需要一样。

 

 

1.   dev.c  -- arch\arm\mach-nuc970， 添加platform_device

        

#if defined(CONFIG_LEDS_TRIGGERS) || defined(CONFIG_LEDS_TRIGGERS_MODULE)

#if defined(CONFIG_LEDS_TRIGGER_HEARTBEAT)
static struct gpio_led gpio_leds[]  = {
	{
		.name			= "led0",
		.default_trigger	= "heartbeat",
		.gpio			= NUC970_PI2,
		
	},
	
};

static struct gpio_led_platform_data gpio_led_info = {
	.leds		= gpio_leds,
	.num_leds	= ARRAY_SIZE(gpio_leds),
};

static struct platform_device leds_gpio = {
	.name	= "leds-nuc970",
	.id	= -1,
	.dev	= {
		.platform_data	= &gpio_led_info,
	},
};
#endif

#endif

 

 

2. 添加platform_driver

   leds-nuc970.c  -- drivers\leds, 

   leds-nuc970.h -- include\linux\platform_data 

 

static void nuc970_led_set(struct led_classdev *led_cdev,
			    enum led_brightness value)
{
	struct nuc970_gpio_led *led = to_gpio(led_cdev);
	struct gpio_led *pd = led->pdata;
	int state = (value ? 1 : 0);

	/* there will be a short delay between setting the output and
	 * going from output to input when using tristate. */

	pr_notice("nuc970_led_set: GPIO%d = %d\n", pd->gpio, state);
	gpio_set_value(pd->gpio, state);

	/*if (pd->flags & NUC970_LEDF_TRISTATE) {
		if (value)
			gpio_direction_output(pd->gpio, state);
		else
			gpio_direction_input(pd->gpio);
	} */
}



static int nuc970_led_probe(struct platform_device *dev)
{
	struct gpio_led_platform_data *pdata_a = dev->dev.platform_data;
	struct gpio_led *pdata;
	struct nuc970_gpio_led *led;
	int ret;

	pdata = &(pdata_a->leds[0]);
	
	led = devm_kzalloc(&dev->dev, sizeof(struct nuc970_gpio_led),
			   GFP_KERNEL);
	if (led == NULL) {
		dev_err(&dev->dev, "No memory for device\n");
		return -ENOMEM;
	}

	pr_notice("nuc970_led_probe\n");

	platform_set_drvdata(dev, led);

	led->cdev.brightness_set = nuc970_led_set;
	led->cdev.default_trigger = pdata->default_trigger;
	led->cdev.name = pdata->name;
	led->cdev.flags |= LED_CORE_SUSPENDRESUME;

	led->pdata = pdata;

	ret = devm_gpio_request(&dev->dev, pdata->gpio, "NUC970_LED");
	if (ret < 0)
		return ret;

	/* no point in having a pull-up if we are always driving */

	//s3c_gpio_setpull(pdata->gpio, S3C_GPIO_PULL_NONE);
	
	pr_notice("leds-nuc970: set(%s)(%d) output\n", pdata->name, pdata->gpio);
	gpio_direction_output(pdata->gpio, 1);

	/* register our new led device */

	ret = led_classdev_register(&dev->dev, &led->cdev);
	if (ret < 0)
		dev_err(&dev->dev, "led_classdev_register failed\n");

	return ret;
}
static struct platform_driver nuc970_led_driver = {
	.probe		= nuc970_led_probe,
	.remove		= nuc970_led_remove,
	.driver		= {
		.name		= "leds-nuc970",
		.owner		= THIS_MODULE,
	},
};

 

 

 

3. platform_driver 的 Kconfig 和 Makefile 修改

Kconfig：

config LEDS_S3C24XX
	tristate "LED Support for Samsung S3C24XX GPIO LEDs"
	depends on LEDS_CLASS
	depends on ARCH_S3C24XX
	help
	  This option enables support for LEDs connected to GPIO lines
	  on Samsung S3C24XX series CPUs, such as the S3C2410 and S3C2440.

++config LEDS_NUC970
++	tristate "LED Support for nuc970 LEDs (PI2)"
++	depends on LEDS_CLASS
++	depends on MACH_NUC970
++	default y
++	help
++	  nuc970 trigger led .

 

Makefile：

obj-$(CONFIG_LEDS_BLINKM)		+= leds-blinkm.o
++obj-$(CONFIG_LEDS_NUC970)		+= leds-nuc970.o

 

 

4. Make menuconfig

Device drivers -> LED Support->

 

 

 

5. Trigger 间隔修改（没试），

ledtrig-heartbeat.c ->

static void led_heartbeat_function(unsigned long data)