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", ®))
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