1/*
2 * Driver for BCM6358 memory-mapped LEDs, based on leds-syscon.c
3 *
4 * Copyright 2015 ��lvaro Fern��ndez Rojas <noltari@gmail.com>
5 *
6 * This program is free software; you can redistribute  it and/or modify it
7 * under  the terms of  the GNU General  Public License as published by the
8 * Free Software Foundation;  either version 2 of the  License, or (at your
9 * option) any later version.
10 */
11#include <linux/delay.h>
12#include <linux/io.h>
13#include <linux/leds.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/platform_device.h>
17#include <linux/spinlock.h>
18
19#define BCM6358_REG_MODE		0x0
20#define BCM6358_REG_CTRL		0x4
21
22#define BCM6358_SLED_CLKDIV_MASK	3
23#define BCM6358_SLED_CLKDIV_1		0
24#define BCM6358_SLED_CLKDIV_2		1
25#define BCM6358_SLED_CLKDIV_4		2
26#define BCM6358_SLED_CLKDIV_8		3
27
28#define BCM6358_SLED_POLARITY		BIT(2)
29#define BCM6358_SLED_BUSY		BIT(3)
30
31#define BCM6358_SLED_MAX_COUNT		32
32#define BCM6358_SLED_WAIT		100
33
34/**
35 * struct bcm6358_led - state container for bcm6358 based LEDs
36 * @cdev: LED class device for this LED
37 * @mem: memory resource
38 * @lock: memory lock
39 * @pin: LED pin number
40 * @active_low: LED is active low
41 */
42struct bcm6358_led {
43	struct led_classdev cdev;
44	void __iomem *mem;
45	spinlock_t *lock;
46	unsigned long pin;
47	bool active_low;
48};
49
50static void bcm6358_led_write(void __iomem *reg, unsigned long data)
51{
52	iowrite32be(data, reg);
53}
54
55static unsigned long bcm6358_led_read(void __iomem *reg)
56{
57	return ioread32be(reg);
58}
59
60static unsigned long bcm6358_led_busy(void __iomem *mem)
61{
62	unsigned long val;
63
64	while ((val = bcm6358_led_read(mem + BCM6358_REG_CTRL)) &
65		BCM6358_SLED_BUSY)
66		udelay(BCM6358_SLED_WAIT);
67
68	return val;
69}
70
71static void bcm6358_led_mode(struct bcm6358_led *led, unsigned long value)
72{
73	unsigned long val;
74
75	bcm6358_led_busy(led->mem);
76
77	val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
78	if ((led->active_low && value == LED_OFF) ||
79	    (!led->active_low && value != LED_OFF))
80		val |= BIT(led->pin);
81	else
82		val &= ~(BIT(led->pin));
83	bcm6358_led_write(led->mem + BCM6358_REG_MODE, val);
84}
85
86static void bcm6358_led_set(struct led_classdev *led_cdev,
87			    enum led_brightness value)
88{
89	struct bcm6358_led *led =
90		container_of(led_cdev, struct bcm6358_led, cdev);
91	unsigned long flags;
92
93	spin_lock_irqsave(led->lock, flags);
94	bcm6358_led_mode(led, value);
95	spin_unlock_irqrestore(led->lock, flags);
96}
97
98static int bcm6358_led(struct device *dev, struct device_node *nc, u32 reg,
99		       void __iomem *mem, spinlock_t *lock)
100{
101	struct bcm6358_led *led;
102	unsigned long flags;
103	const char *state;
104	int rc;
105
106	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
107	if (!led)
108		return -ENOMEM;
109
110	led->pin = reg;
111	led->mem = mem;
112	led->lock = lock;
113
114	if (of_property_read_bool(nc, "active-low"))
115		led->active_low = true;
116
117	led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name;
118	led->cdev.default_trigger = of_get_property(nc,
119						    "linux,default-trigger",
120						    NULL);
121
122	spin_lock_irqsave(lock, flags);
123	if (!of_property_read_string(nc, "default-state", &state)) {
124		if (!strcmp(state, "on")) {
125			led->cdev.brightness = LED_FULL;
126		} else if (!strcmp(state, "keep")) {
127			unsigned long val;
128
129			bcm6358_led_busy(led->mem);
130
131			val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
132			val &= BIT(led->pin);
133			if ((led->active_low && !val) ||
134			    (!led->active_low && val))
135				led->cdev.brightness = LED_FULL;
136			else
137				led->cdev.brightness = LED_OFF;
138		} else {
139			led->cdev.brightness = LED_OFF;
140		}
141	} else {
142		led->cdev.brightness = LED_OFF;
143	}
144	bcm6358_led_mode(led, led->cdev.brightness);
145	spin_unlock_irqrestore(lock, flags);
146
147	led->cdev.brightness_set = bcm6358_led_set;
148
149	rc = led_classdev_register(dev, &led->cdev);
150	if (rc < 0)
151		return rc;
152
153	dev_dbg(dev, "registered LED %s\n", led->cdev.name);
154
155	return 0;
156}
157
158static int bcm6358_leds_probe(struct platform_device *pdev)
159{
160	struct device *dev = &pdev->dev;
161	struct device_node *np = pdev->dev.of_node;
162	struct device_node *child;
163	struct resource *mem_r;
164	void __iomem *mem;
165	spinlock_t *lock; /* memory lock */
166	unsigned long val;
167	u32 clk_div;
168
169	mem_r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
170	if (!mem_r)
171		return -EINVAL;
172
173	mem = devm_ioremap_resource(dev, mem_r);
174	if (IS_ERR(mem))
175		return PTR_ERR(mem);
176
177	lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
178	if (!lock)
179		return -ENOMEM;
180
181	spin_lock_init(lock);
182
183	val = bcm6358_led_busy(mem);
184	val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
185	if (of_property_read_bool(np, "brcm,clk-dat-low"))
186		val |= BCM6358_SLED_POLARITY;
187	of_property_read_u32(np, "brcm,clk-div", &clk_div);
188	switch (clk_div) {
189	case 8:
190		val |= BCM6358_SLED_CLKDIV_8;
191		break;
192	case 4:
193		val |= BCM6358_SLED_CLKDIV_4;
194		break;
195	case 2:
196		val |= BCM6358_SLED_CLKDIV_2;
197		break;
198	default:
199		val |= BCM6358_SLED_CLKDIV_1;
200		break;
201	}
202	bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
203
204	for_each_available_child_of_node(np, child) {
205		int rc;
206		u32 reg;
207
208		if (of_property_read_u32(child, "reg", &reg))
209			continue;
210
211		if (reg >= BCM6358_SLED_MAX_COUNT) {
212			dev_err(dev, "invalid LED (%u >= %d)\n", reg,
213				BCM6358_SLED_MAX_COUNT);
214			continue;
215		}
216
217		rc = bcm6358_led(dev, child, reg, mem, lock);
218		if (rc < 0) {
219			of_node_put(child);
220			return rc;
221		}
222	}
223
224	return 0;
225}
226
227static const struct of_device_id bcm6358_leds_of_match[] = {
228	{ .compatible = "brcm,bcm6358-leds", },
229	{ },
230};
231MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
232
233static struct platform_driver bcm6358_leds_driver = {
234	.probe = bcm6358_leds_probe,
235	.driver = {
236		.name = "leds-bcm6358",
237		.of_match_table = bcm6358_leds_of_match,
238	},
239};
240
241module_platform_driver(bcm6358_leds_driver);
242
243MODULE_AUTHOR("��lvaro Fern��ndez Rojas <noltari@gmail.com>");
244MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
245MODULE_LICENSE("GPL v2");
246MODULE_ALIAS("platform:leds-bcm6358");
247