1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Driver for BCM6358 memory-mapped LEDs, based on leds-syscon.c
  4 *
  5 * Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com>
  6 */
  7#include <linux/delay.h>
  8#include <linux/io.h>
  9#include <linux/leds.h>
 10#include <linux/module.h>
 11#include <linux/of.h>
 12#include <linux/platform_device.h>
 13#include <linux/spinlock.h>
 14
 15#define BCM6358_REG_MODE		0x0
 16#define BCM6358_REG_CTRL		0x4
 17
 18#define BCM6358_SLED_CLKDIV_MASK	3
 19#define BCM6358_SLED_CLKDIV_1		0
 20#define BCM6358_SLED_CLKDIV_2		1
 21#define BCM6358_SLED_CLKDIV_4		2
 22#define BCM6358_SLED_CLKDIV_8		3
 23
 24#define BCM6358_SLED_POLARITY		BIT(2)
 25#define BCM6358_SLED_BUSY		BIT(3)
 26
 27#define BCM6358_SLED_MAX_COUNT		32
 28#define BCM6358_SLED_WAIT		100
 29
 30/**
 31 * struct bcm6358_led - state container for bcm6358 based LEDs
 32 * @cdev: LED class device for this LED
 33 * @mem: memory resource
 34 * @lock: memory lock
 35 * @pin: LED pin number
 36 * @active_low: LED is active low
 37 */
 38struct bcm6358_led {
 39	struct led_classdev cdev;
 40	void __iomem *mem;
 41	spinlock_t *lock;
 42	unsigned long pin;
 43	bool active_low;
 44};
 45
 46static void bcm6358_led_write(void __iomem *reg, unsigned long data)
 47{
 48#ifdef CONFIG_CPU_BIG_ENDIAN
 49	iowrite32be(data, reg);
 50#else
 51	writel(data, reg);
 52#endif
 53}
 54
 55static unsigned long bcm6358_led_read(void __iomem *reg)
 56{
 57#ifdef CONFIG_CPU_BIG_ENDIAN
 58	return ioread32be(reg);
 59#else
 60	return readl(reg);
 61#endif
 62}
 63
 64static unsigned long bcm6358_led_busy(void __iomem *mem)
 65{
 66	unsigned long val;
 67
 68	while ((val = bcm6358_led_read(mem + BCM6358_REG_CTRL)) &
 69		BCM6358_SLED_BUSY)
 70		udelay(BCM6358_SLED_WAIT);
 71
 72	return val;
 73}
 74
 75static void bcm6358_led_set(struct led_classdev *led_cdev,
 76			    enum led_brightness value)
 77{
 78	struct bcm6358_led *led =
 79		container_of(led_cdev, struct bcm6358_led, cdev);
 80	unsigned long flags, val;
 81
 82	spin_lock_irqsave(led->lock, flags);
 83	bcm6358_led_busy(led->mem);
 84	val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
 85	if ((led->active_low && value == LED_OFF) ||
 86	    (!led->active_low && value != LED_OFF))
 87		val |= BIT(led->pin);
 88	else
 89		val &= ~(BIT(led->pin));
 90	bcm6358_led_write(led->mem + BCM6358_REG_MODE, val);
 91	spin_unlock_irqrestore(led->lock, flags);
 92}
 93
 94static int bcm6358_led(struct device *dev, struct device_node *nc, u32 reg,
 95		       void __iomem *mem, spinlock_t *lock)
 96{
 97	struct bcm6358_led *led;
 98	const char *state;
 99	int rc;
100
101	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
102	if (!led)
103		return -ENOMEM;
104
105	led->pin = reg;
106	led->mem = mem;
107	led->lock = lock;
108
109	if (of_property_read_bool(nc, "active-low"))
110		led->active_low = true;
111
112	led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name;
113	led->cdev.default_trigger = of_get_property(nc,
114						    "linux,default-trigger",
115						    NULL);
116
117	if (!of_property_read_string(nc, "default-state", &state)) {
118		if (!strcmp(state, "on")) {
119			led->cdev.brightness = LED_FULL;
120		} else if (!strcmp(state, "keep")) {
121			unsigned long val;
122			val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
123			val &= BIT(led->pin);
124			if ((led->active_low && !val) ||
125			    (!led->active_low && val))
126				led->cdev.brightness = LED_FULL;
127			else
128				led->cdev.brightness = LED_OFF;
129		} else {
130			led->cdev.brightness = LED_OFF;
131		}
132	} else {
133		led->cdev.brightness = LED_OFF;
134	}
135
136	bcm6358_led_set(&led->cdev, led->cdev.brightness);
137
138	led->cdev.brightness_set = bcm6358_led_set;
139
140	rc = led_classdev_register(dev, &led->cdev);
141	if (rc < 0)
142		return rc;
143
144	dev_dbg(dev, "registered LED %s\n", led->cdev.name);
145
146	return 0;
147}
148
149static int bcm6358_leds_probe(struct platform_device *pdev)
150{
151	struct device *dev = &pdev->dev;
152	struct device_node *np = pdev->dev.of_node;
153	struct device_node *child;
154	void __iomem *mem;
155	spinlock_t *lock; /* memory lock */
156	unsigned long val;
157	u32 clk_div;
158
159	mem = devm_platform_ioremap_resource(pdev, 0);
160	if (IS_ERR(mem))
161		return PTR_ERR(mem);
162
163	lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
164	if (!lock)
165		return -ENOMEM;
166
167	spin_lock_init(lock);
168
169	val = bcm6358_led_busy(mem);
170	val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
171	if (of_property_read_bool(np, "brcm,clk-dat-low"))
172		val |= BCM6358_SLED_POLARITY;
173	of_property_read_u32(np, "brcm,clk-div", &clk_div);
174	switch (clk_div) {
175	case 8:
176		val |= BCM6358_SLED_CLKDIV_8;
177		break;
178	case 4:
179		val |= BCM6358_SLED_CLKDIV_4;
180		break;
181	case 2:
182		val |= BCM6358_SLED_CLKDIV_2;
183		break;
184	default:
185		val |= BCM6358_SLED_CLKDIV_1;
186		break;
187	}
188	bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
189
190	for_each_available_child_of_node(np, child) {
191		int rc;
192		u32 reg;
193
194		if (of_property_read_u32(child, "reg", &reg))
195			continue;
196
197		if (reg >= BCM6358_SLED_MAX_COUNT) {
198			dev_err(dev, "invalid LED (%u >= %d)\n", reg,
199				BCM6358_SLED_MAX_COUNT);
200			continue;
201		}
202
203		rc = bcm6358_led(dev, child, reg, mem, lock);
204		if (rc < 0) {
205			of_node_put(child);
206			return rc;
207		}
208	}
209
210	return 0;
211}
212
213static const struct of_device_id bcm6358_leds_of_match[] = {
214	{ .compatible = "brcm,bcm6358-leds", },
215	{ },
216};
217MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
218
219static struct platform_driver bcm6358_leds_driver = {
220	.probe = bcm6358_leds_probe,
221	.driver = {
222		.name = "leds-bcm6358",
223		.of_match_table = bcm6358_leds_of_match,
224	},
225};
226
227module_platform_driver(bcm6358_leds_driver);
228
229MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
230MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
231MODULE_LICENSE("GPL v2");
232MODULE_ALIAS("platform:leds-bcm6358");