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[linux.git] / drivers / leds / leds-bcm6358.c
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
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
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
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
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
94 static 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
149 static 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         struct resource *mem_r;
155         void __iomem *mem;
156         spinlock_t *lock; /* memory lock */
157         unsigned long val;
158         u32 clk_div;
159
160         mem_r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
161         if (!mem_r)
162                 return -EINVAL;
163
164         mem = devm_ioremap_resource(dev, mem_r);
165         if (IS_ERR(mem))
166                 return PTR_ERR(mem);
167
168         lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
169         if (!lock)
170                 return -ENOMEM;
171
172         spin_lock_init(lock);
173
174         val = bcm6358_led_busy(mem);
175         val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
176         if (of_property_read_bool(np, "brcm,clk-dat-low"))
177                 val |= BCM6358_SLED_POLARITY;
178         of_property_read_u32(np, "brcm,clk-div", &clk_div);
179         switch (clk_div) {
180         case 8:
181                 val |= BCM6358_SLED_CLKDIV_8;
182                 break;
183         case 4:
184                 val |= BCM6358_SLED_CLKDIV_4;
185                 break;
186         case 2:
187                 val |= BCM6358_SLED_CLKDIV_2;
188                 break;
189         default:
190                 val |= BCM6358_SLED_CLKDIV_1;
191                 break;
192         }
193         bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
194
195         for_each_available_child_of_node(np, child) {
196                 int rc;
197                 u32 reg;
198
199                 if (of_property_read_u32(child, "reg", &reg))
200                         continue;
201
202                 if (reg >= BCM6358_SLED_MAX_COUNT) {
203                         dev_err(dev, "invalid LED (%u >= %d)\n", reg,
204                                 BCM6358_SLED_MAX_COUNT);
205                         continue;
206                 }
207
208                 rc = bcm6358_led(dev, child, reg, mem, lock);
209                 if (rc < 0) {
210                         of_node_put(child);
211                         return rc;
212                 }
213         }
214
215         return 0;
216 }
217
218 static const struct of_device_id bcm6358_leds_of_match[] = {
219         { .compatible = "brcm,bcm6358-leds", },
220         { },
221 };
222 MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
223
224 static struct platform_driver bcm6358_leds_driver = {
225         .probe = bcm6358_leds_probe,
226         .driver = {
227                 .name = "leds-bcm6358",
228                 .of_match_table = bcm6358_leds_of_match,
229         },
230 };
231
232 module_platform_driver(bcm6358_leds_driver);
233
234 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
235 MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
236 MODULE_LICENSE("GPL v2");
237 MODULE_ALIAS("platform:leds-bcm6358");