ar71xx: add LED driver NU801

The MR18 uses a 3-channel 16-bit PWM Constant Current Driver
for its status LED.

Signed-off-by: Chris R Blake <chrisrblake93@gmail.com>

SVN-Revision: 47848

2 files changed, 434 insertions, 0 deletions

diff --git a/target/linux/ar71xx/files/drivers/leds/leds-nu801.c b/target/linux/ar71xx/files/drivers/leds/leds-nu801.c
new file mode 100644
index 0000000000..0dfc015653
--- /dev/null
+++ b/target/linux/ar71xx/files/drivers/leds/leds-nu801.c
@@ -0,0 +1,396 @@
+/*
+ * LED driver for NU801
+ *
+ * Kevin Paul Herbert
+ * Copyright (c) 2012, Meraki, Inc.
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
+#include <linux/leds-nu801.h>
+
+#include <asm/gpio.h>
+#include <linux/of_gpio.h>
+
+#define MAX_NAME_LENGTH 24
+#define NUM_COLORS 3
+
+static const char * const led_nu801_colors[] = { "blue", "green", "red" };
+
+struct led_nu801_led_data {
+	struct led_classdev cdev;
+	struct led_nu801_data *controller;
+	enum led_brightness level;
+	char name[MAX_NAME_LENGTH];
+};
+
+struct led_nu801_data {
+	unsigned cki;
+	unsigned sdi;
+	int lei;
+	struct delayed_work work;
+	struct led_nu801_led_data *led_chain;
+	int num_leds;
+	const char *device_name;
+	const char *name;
+	u32 ndelay;
+	atomic_t pending;
+};
+
+static void led_nu801_work(struct work_struct *work)
+{
+	struct led_nu801_data	*controller =
+		container_of(work, struct led_nu801_data, work.work);
+	struct led_nu801_led_data *led;
+	u16 bit;
+	u16 brightness;
+	int index;
+
+	for (index = 0; index < controller->num_leds; index++) {
+		led = &controller->led_chain[index];
+		brightness = led->level << 8; /* To do: gamma correction */
+		for (bit = 0x8000; bit; bit = bit >> 1) {
+			gpio_set_value(controller->sdi,
+				       (brightness & bit) != 0);
+			gpio_set_value(controller->cki, 1);
+			if (unlikely(((index == (controller->num_leds - 1)) &&
+				      (bit == 1) &&
+				      (controller->lei < 0)))) {
+				udelay(600);
+			} else {
+				ndelay(controller->ndelay);
+			}
+			gpio_set_value(controller->cki, 0);
+			ndelay(controller->ndelay);
+		}
+	}
+	if (controller->lei >= 0) {
+		gpio_set_value(controller->lei, 1);
+		ndelay(controller->ndelay);
+		gpio_set_value(controller->lei, 0);
+	}
+	atomic_set(&controller->pending, 1);
+}
+
+static void led_nu801_set(struct led_classdev *led_cdev,
+			  enum led_brightness value)
+{
+	struct led_nu801_led_data *led_dat =
+		container_of(led_cdev, struct led_nu801_led_data, cdev);
+	struct led_nu801_data *controller = led_dat->controller;
+
+	if (led_dat->level != value) {
+		led_dat->level = value;
+		if (atomic_dec_and_test(&controller->pending))
+			schedule_delayed_work(&led_dat->controller->work,
+					      (HZ/1000) + 1);
+	}
+}
+
+static int __init led_nu801_create(struct led_nu801_data *controller,
+				    struct device *parent,
+				    int index,
+				    enum led_brightness brightness,
+#ifdef CONFIG_LEDS_TRIGGERS
+				    const char *default_trigger,
+#endif
+				    const char *color)
+{
+	struct led_nu801_led_data *led = &controller->led_chain[index];
+	int ret;
+
+	scnprintf(led->name, sizeof(led->name), "%s:%s:%s%d",
+		  controller->device_name, color, controller->name,
+		  (controller->num_leds - (index + 1)) / NUM_COLORS);
+	led->cdev.name = led->name;
+	led->cdev.brightness_set = led_nu801_set;
+#ifdef CONFIG_LEDS_TRIGGERS
+	led->cdev.default_trigger = default_trigger;
+#endif
+	led->level = brightness;
+	led->controller = controller;
+	ret = led_classdev_register(parent, &led->cdev);
+	if (ret < 0)
+		goto err;
+
+	return 0;
+
+err:
+	kfree(led);
+	return ret;
+}
+
+static int __init
+led_nu801_create_chain(const struct led_nu801_template *template,
+			struct led_nu801_data *controller,
+			struct device *parent)
+{
+	int ret;
+	int index;
+
+	controller->cki = template->cki;
+	controller->sdi = template->sdi;
+	controller->lei = template->lei;
+	controller->num_leds = template->num_leds * 3;
+	controller->device_name = template->device_name;
+	controller->name = template->name;
+	controller->ndelay = template->ndelay;
+	atomic_set(&controller->pending, 1);
+
+	controller->led_chain = kzalloc(sizeof(struct led_nu801_led_data) *
+					controller->num_leds, GFP_KERNEL);
+
+	if (!controller->led_chain)
+		return -ENOMEM;
+
+	ret = gpio_request(controller->cki, template->name);
+	if (ret < 0)
+		goto err_free_chain;
+
+	ret = gpio_request(controller->sdi, template->name);
+	if (ret < 0)
+		goto err_ret_cki;
+
+	if (controller->lei >= 0) {
+		ret = gpio_request(controller->lei, template->name);
+		if (ret < 0)
+			goto err_ret_sdi;
+		ret = gpio_direction_output(controller->lei, 0);
+		if (ret < 0)
+			goto err_ret_lei;
+	}
+
+	ret = gpio_direction_output(controller->cki, 0);
+	if (ret < 0)
+		goto err_ret_lei;
+
+	ret = gpio_direction_output(controller->sdi, 0);
+	if (ret < 0)
+		goto err_ret_lei;
+
+	for (index = 0; index < controller->num_leds; index++) {
+		ret = led_nu801_create(controller, parent, index,
+			template->init_brightness
+			[index % NUM_COLORS],
+#ifdef CONFIG_LEDS_TRIGGERS
+			template->default_trigger,
+#endif
+			template->led_colors[index % NUM_COLORS] ?
+			template->led_colors[index % NUM_COLORS] :
+			led_nu801_colors[index % NUM_COLORS]);
+		if (ret < 0)
+			goto err_ret_sdi;
+	}
+
+	INIT_DELAYED_WORK(&controller->work, led_nu801_work);
+	schedule_delayed_work(&controller->work, 0);
+
+	return 0;
+
+err_ret_lei:
+	if (controller->lei >= 0)
+		gpio_free(controller->lei);
+err_ret_sdi:
+	gpio_free(controller->sdi);
+err_ret_cki:
+	gpio_free(controller->cki);
+err_free_chain:
+	kfree(controller->led_chain);
+
+	return ret;
+}
+
+static void led_nu801_delete_chain(struct led_nu801_data *controller)
+{
+	struct led_nu801_led_data *led_chain;
+	struct led_nu801_led_data *led;
+	int index;
+	int num_leds;
+
+	led_chain = controller->led_chain;
+	controller->led_chain = 0;
+	num_leds = controller->num_leds;
+	controller->num_leds = 0;
+	cancel_delayed_work_sync(&controller->work);
+
+	for (index = 0; index < num_leds; index++) {
+		led = &led_chain[index];
+		led_classdev_unregister(&led->cdev);
+	}
+
+	gpio_free(controller->cki);
+	gpio_free(controller->sdi);
+	if (controller->lei >= 0)
+		gpio_free(controller->lei);
+
+	kfree(led_chain);
+}
+
+static struct led_nu801_data * __init
+leds_nu801_create_of(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node, *child;
+	struct led_nu801_data *controllers;
+	int count = 0, ret;
+	int i = 0;
+
+	for_each_child_of_node(np, child)
+		count++;
+	if (!count)
+		return NULL;
+
+	controllers = kzalloc(sizeof(struct led_nu801_data) * count,
+			      GFP_KERNEL);
+	if (!controllers)
+		return NULL;
+
+	for_each_child_of_node(np, child) {
+		const char *state;
+		struct led_nu801_template template = {};
+		struct device_node *colors;
+		int jj;
+
+		template.cki = of_get_named_gpio_flags(child, "cki", 0, NULL);
+		template.sdi = of_get_named_gpio_flags(child, "sdi", 0, NULL);
+		if (of_find_property(child, "lei", NULL)) {
+			template.lei = of_get_named_gpio_flags(child, "lei",
+							       0, NULL);
+		} else {
+			template.lei = -1;
+		}
+		of_property_read_u32(child, "ndelay", &template.ndelay);
+		of_property_read_u32(child, "num_leds", &template.num_leds);
+		template.name = of_get_property(child, "label", NULL) ? :
+			child->name;
+		template.default_trigger = of_get_property(child,
+			"default-trigger", NULL);
+
+		jj = 0;
+		for_each_child_of_node(child, colors) {
+			template.led_colors[jj] = of_get_property(colors,
+				 "label", NULL);
+			state = of_get_property(colors, "state", NULL);
+			if (!strncmp(state, "off", 3))
+				template.init_brightness[jj] = LED_OFF;
+			else if (!strncmp(state, "half", 4))
+				template.init_brightness[jj] = LED_HALF;
+			else if (!strncmp(state, "full", 4))
+				template.init_brightness[jj] = LED_FULL;
+			jj++;
+		}
+
+		ret = led_nu801_create_chain(&template,
+					     &controllers[i],
+					     &pdev->dev);
+		if (ret < 0)
+			goto err;
+		i++;
+	}
+
+	return controllers;
+
+err:
+	for (i = i - 1; i >= 0; i--)
+		led_nu801_delete_chain(&controllers[i]);
+	kfree(controllers);
+	return NULL;
+}
+
+static int __init led_nu801_probe(struct platform_device *pdev)
+{
+	struct led_nu801_platform_data *pdata = pdev->dev.platform_data;
+	struct led_nu801_data *controllers;
+	int i, ret = 0;
+
+	if (!(pdata && pdata->num_controllers)) {
+		controllers = leds_nu801_create_of(pdev);
+		if (!controllers)
+			return -ENODEV;
+	}
+
+	controllers = kzalloc(sizeof(struct led_nu801_data) *
+			      pdata->num_controllers, GFP_KERNEL);
+	if (!controllers)
+		return -ENOMEM;
+
+	for (i = 0; i < pdata->num_controllers; i++) {
+		ret = led_nu801_create_chain(&pdata->template[i],
+					      &controllers[i],
+					      &pdev->dev);
+		if (ret < 0)
+			goto err;
+	}
+
+	platform_set_drvdata(pdev, controllers);
+
+	return 0;
+
+err:
+	for (i = i - 1; i >= 0; i--)
+		led_nu801_delete_chain(&controllers[i]);
+
+	kfree(controllers);
+
+	return ret;
+}
+
+static int led_nu801_remove(struct platform_device *pdev)
+{
+	int i;
+	struct led_nu801_platform_data *pdata = pdev->dev.platform_data;
+	struct led_nu801_data *controllers;
+
+	controllers = platform_get_drvdata(pdev);
+
+	for (i = 0; i < pdata->num_controllers; i++)
+		led_nu801_delete_chain(&controllers[i]);
+
+	kfree(controllers);
+
+	return 0;
+}
+
+static const struct of_device_id of_numen_leds_match[] = {
+	{ .compatible = "numen,leds-nu801", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
+
+static struct platform_driver led_nu801_driver = {
+	.probe		= led_nu801_probe,
+	.remove		= led_nu801_remove,
+	.driver		= {
+		.name	= "leds-nu801",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_numen_leds_match,
+	},
+};
+
+static int __init led_nu801_init(void)
+{
+	return platform_driver_register(&led_nu801_driver);
+}
+
+static void __exit led_nu801_exit(void)
+{
+	platform_driver_unregister(&led_nu801_driver);
+}
+
+module_init(led_nu801_init);
+module_exit(led_nu801_exit);
+
+MODULE_AUTHOR("Kevin Paul Herbert <kph@meraki.net>");
+MODULE_DESCRIPTION("NU801 LED driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:leds-nu801");
diff --git a/target/linux/ar71xx/files/include/linux/leds-nu801.h b/target/linux/ar71xx/files/include/linux/leds-nu801.h
new file mode 100644
index 0000000000..0fc310d277
--- /dev/null
+++ b/target/linux/ar71xx/files/include/linux/leds-nu801.h
@@ -0,0 +1,38 @@
+#ifndef __LEDS_NU801_H__
+#define __LEDS_NU801_H__
+
+/*
+ * Definitions for LED driver for NU801
+ *
+ * Kevin Paul Herbert
+ * Copyright (c) 2012, Meraki, Inc.
+ *
+ * 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/leds.h>
+
+struct led_nu801_template {
+	const char *device_name;	/* Name of the platform device */
+	const char *name;	/* Name of this LED chain */
+	int num_leds;		/* Number of LEDs in the chain */
+	unsigned cki;		/* GPIO pin for CKI */
+	unsigned sdi;		/* GPIO pin for SDI */
+	int lei;		/* GPIO pin for LEI; < 0 if none */
+	u32 ndelay;		/* Delay in nanoseconds */
+	enum led_brightness init_brightness[3]; /* Default rgb state */
+#ifdef CONFIG_LEDS_TRIGGERS
+	const char *default_trigger; /* default trigger */
+#endif
+	const char *led_colors[3];  /* rgb color order */
+};
+
+struct led_nu801_platform_data {
+	int num_controllers;	/* Numnber of controllers */
+	struct led_nu801_template *template; /* Template per controller */
+};
+
+#endif /* __LEDS_NU801_H__ */