1/*
  2 * Driver for BCM6358 memory-mapped LEDs, based on leds-syscon.c
  3 *
  4 * Copyright 2015 Álvaro Fernández 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#ifdef CONFIG_CPU_BIG_ENDIAN
 53	iowrite32be(data, reg);
 54#else
 55	writel(data, reg);
 56#endif
 57}
 58
 59static unsigned long bcm6358_led_read(void __iomem *reg)
 60{
 61#ifdef CONFIG_CPU_BIG_ENDIAN
 62	return ioread32be(reg);
 63#else
 64	return readl(reg);
 65#endif
 66}
 67
 68static unsigned long bcm6358_led_busy(void __iomem *mem)
 69{
 70	unsigned long val;
 71
 72	while ((val = bcm6358_led_read(mem + BCM6358_REG_CTRL)) &
 73		BCM6358_SLED_BUSY)
 74		udelay(BCM6358_SLED_WAIT);
 75
 76	return val;
 77}
 78
 79static void bcm6358_led_set(struct led_classdev *led_cdev,
 80			    enum led_brightness value)
 81{
 82	struct bcm6358_led *led =
 83		container_of(led_cdev, struct bcm6358_led, cdev);
 84	unsigned long flags, val;
 85
 86	spin_lock_irqsave(led->lock, flags);
 87	bcm6358_led_busy(led->mem);
 88	val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
 89	if ((led->active_low && value == LED_OFF) ||
 90	    (!led->active_low && value != LED_OFF))
 91		val |= BIT(led->pin);
 92	else
 93		val &= ~(BIT(led->pin));
 94	bcm6358_led_write(led->mem + BCM6358_REG_MODE, val);
 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	const char *state;
103	int rc;
104
105	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
106	if (!led)
107		return -ENOMEM;
108
109	led->pin = reg;
110	led->mem = mem;
111	led->lock = lock;
112
113	if (of_property_read_bool(nc, "active-low"))
114		led->active_low = true;
115
116	led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name;
117	led->cdev.default_trigger = of_get_property(nc,
118						    "linux,default-trigger",
119						    NULL);
120
121	if (!of_property_read_string(nc, "default-state", &state)) {
122		if (!strcmp(state, "on")) {
123			led->cdev.brightness = LED_FULL;
124		} else if (!strcmp(state, "keep")) {
125			unsigned long val;
126			val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
127			val &= BIT(led->pin);
128			if ((led->active_low && !val) ||
129			    (!led->active_low && val))
130				led->cdev.brightness = LED_FULL;
131			else
132				led->cdev.brightness = LED_OFF;
133		} else {
134			led->cdev.brightness = LED_OFF;
135		}
136	} else {
137		led->cdev.brightness = LED_OFF;
138	}
139
140	bcm6358_led_set(&led->cdev, led->cdev.brightness);
141
142	led->cdev.brightness_set = bcm6358_led_set;
143
144	rc = led_classdev_register(dev, &led->cdev);
145	if (rc < 0)
146		return rc;
147
148	dev_dbg(dev, "registered LED %s\n", led->cdev.name);
149
150	return 0;
151}
152
153static int bcm6358_leds_probe(struct platform_device *pdev)
154{
155	struct device *dev = &pdev->dev;
156	struct device_node *np = pdev->dev.of_node;
157	struct device_node *child;
158	struct resource *mem_r;
159	void __iomem *mem;
160	spinlock_t *lock; /* memory lock */
161	unsigned long val;
162	u32 clk_div;
163
164	mem_r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
165	if (!mem_r)
166		return -EINVAL;
167
168	mem = devm_ioremap_resource(dev, mem_r);
169	if (IS_ERR(mem))
170		return PTR_ERR(mem);
171
172	lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
173	if (!lock)
174		return -ENOMEM;
175
176	spin_lock_init(lock);
177
178	val = bcm6358_led_busy(mem);
179	val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
180	if (of_property_read_bool(np, "brcm,clk-dat-low"))
181		val |= BCM6358_SLED_POLARITY;
182	of_property_read_u32(np, "brcm,clk-div", &clk_div);
183	switch (clk_div) {
184	case 8:
185		val |= BCM6358_SLED_CLKDIV_8;
186		break;
187	case 4:
188		val |= BCM6358_SLED_CLKDIV_4;
189		break;
190	case 2:
191		val |= BCM6358_SLED_CLKDIV_2;
192		break;
193	default:
194		val |= BCM6358_SLED_CLKDIV_1;
195		break;
196	}
197	bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
198
199	for_each_available_child_of_node(np, child) {
200		int rc;
201		u32 reg;
202
203		if (of_property_read_u32(child, "reg", &reg))
204			continue;
205
206		if (reg >= BCM6358_SLED_MAX_COUNT) {
207			dev_err(dev, "invalid LED (%u >= %d)\n", reg,
208				BCM6358_SLED_MAX_COUNT);
209			continue;
210		}
211
212		rc = bcm6358_led(dev, child, reg, mem, lock);
213		if (rc < 0) {
214			of_node_put(child);
215			return rc;
216		}
217	}
218
219	return 0;
220}
221
222static const struct of_device_id bcm6358_leds_of_match[] = {
223	{ .compatible = "brcm,bcm6358-leds", },
224	{ },
225};
226MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
227
228static struct platform_driver bcm6358_leds_driver = {
229	.probe = bcm6358_leds_probe,
230	.driver = {
231		.name = "leds-bcm6358",
232		.of_match_table = bcm6358_leds_of_match,
233	},
234};
235
236module_platform_driver(bcm6358_leds_driver);
237
238MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
239MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
240MODULE_LICENSE("GPL v2");
241MODULE_ALIAS("platform:leds-bcm6358");