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  */
38 struct 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 
bcm6358_led_write(void __iomem * reg,unsigned long data)46 static 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 
bcm6358_led_read(void __iomem * reg)55 static 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 
bcm6358_led_busy(void __iomem * mem)64 static 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 
bcm6358_led_set(struct led_classdev * led_cdev,enum led_brightness value)75 static 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 
bcm6358_led(struct device * dev,struct device_node * nc,u32 reg,void __iomem * mem,spinlock_t * lock)94 static int bcm6358_led(struct device *dev, struct device_node *nc, u32 reg,
95 		       void __iomem *mem, spinlock_t *lock)
96 {
97 	struct led_init_data init_data = {};
98 	struct bcm6358_led *led;
99 	enum led_default_state state;
100 	unsigned long val;
101 	int rc;
102 
103 	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
104 	if (!led)
105 		return -ENOMEM;
106 
107 	led->pin = reg;
108 	led->mem = mem;
109 	led->lock = lock;
110 
111 	if (of_property_read_bool(nc, "active-low"))
112 		led->active_low = true;
113 
114 	init_data.fwnode = of_fwnode_handle(nc);
115 
116 	state = led_init_default_state_get(init_data.fwnode);
117 	switch (state) {
118 	case LEDS_DEFSTATE_ON:
119 		led->cdev.brightness = LED_FULL;
120 		break;
121 	case LEDS_DEFSTATE_KEEP:
122 		val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
123 		val &= BIT(led->pin);
124 		if ((led->active_low && !val) || (!led->active_low && val))
125 			led->cdev.brightness = LED_FULL;
126 		else
127 			led->cdev.brightness = LED_OFF;
128 		break;
129 	default:
130 		led->cdev.brightness = LED_OFF;
131 	}
132 
133 	bcm6358_led_set(&led->cdev, led->cdev.brightness);
134 
135 	led->cdev.brightness_set = bcm6358_led_set;
136 
137 	rc = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
138 	if (rc < 0)
139 		return rc;
140 
141 	dev_dbg(dev, "registered LED %s\n", led->cdev.name);
142 
143 	return 0;
144 }
145 
bcm6358_leds_probe(struct platform_device * pdev)146 static int bcm6358_leds_probe(struct platform_device *pdev)
147 {
148 	struct device *dev = &pdev->dev;
149 	struct device_node *np = dev_of_node(&pdev->dev);
150 	struct device_node *child;
151 	void __iomem *mem;
152 	spinlock_t *lock; /* memory lock */
153 	unsigned long val;
154 	u32 clk_div;
155 
156 	mem = devm_platform_ioremap_resource(pdev, 0);
157 	if (IS_ERR(mem))
158 		return PTR_ERR(mem);
159 
160 	lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
161 	if (!lock)
162 		return -ENOMEM;
163 
164 	spin_lock_init(lock);
165 
166 	val = bcm6358_led_busy(mem);
167 	val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
168 	if (of_property_read_bool(np, "brcm,clk-dat-low"))
169 		val |= BCM6358_SLED_POLARITY;
170 	of_property_read_u32(np, "brcm,clk-div", &clk_div);
171 	switch (clk_div) {
172 	case 8:
173 		val |= BCM6358_SLED_CLKDIV_8;
174 		break;
175 	case 4:
176 		val |= BCM6358_SLED_CLKDIV_4;
177 		break;
178 	case 2:
179 		val |= BCM6358_SLED_CLKDIV_2;
180 		break;
181 	default:
182 		val |= BCM6358_SLED_CLKDIV_1;
183 		break;
184 	}
185 	bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
186 
187 	for_each_available_child_of_node(np, child) {
188 		int rc;
189 		u32 reg;
190 
191 		if (of_property_read_u32(child, "reg", &reg))
192 			continue;
193 
194 		if (reg >= BCM6358_SLED_MAX_COUNT) {
195 			dev_err(dev, "invalid LED (%u >= %d)\n", reg,
196 				BCM6358_SLED_MAX_COUNT);
197 			continue;
198 		}
199 
200 		rc = bcm6358_led(dev, child, reg, mem, lock);
201 		if (rc < 0) {
202 			of_node_put(child);
203 			return rc;
204 		}
205 	}
206 
207 	return 0;
208 }
209 
210 static const struct of_device_id bcm6358_leds_of_match[] = {
211 	{ .compatible = "brcm,bcm6358-leds", },
212 	{ },
213 };
214 MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
215 
216 static struct platform_driver bcm6358_leds_driver = {
217 	.probe = bcm6358_leds_probe,
218 	.driver = {
219 		.name = "leds-bcm6358",
220 		.of_match_table = bcm6358_leds_of_match,
221 	},
222 };
223 
224 module_platform_driver(bcm6358_leds_driver);
225 
226 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
227 MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
228 MODULE_LICENSE("GPL v2");
229 MODULE_ALIAS("platform:leds-bcm6358");
230