1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Driver for BCM6328 memory-mapped LEDs, based on leds-syscon.c
4  *
5  * Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com>
6  * Copyright 2015 Jonas Gorski <jogo@openwrt.org>
7  */
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 BCM6328_REG_INIT		0x00
16 #define BCM6328_REG_MODE_HI		0x04
17 #define BCM6328_REG_MODE_LO		0x08
18 #define BCM6328_REG_HWDIS		0x0c
19 #define BCM6328_REG_STROBE		0x10
20 #define BCM6328_REG_LNKACTSEL_HI	0x14
21 #define BCM6328_REG_LNKACTSEL_LO	0x18
22 #define BCM6328_REG_RBACK		0x1c
23 #define BCM6328_REG_SERMUX		0x20
24 
25 #define BCM6328_LED_MAX_COUNT		24
26 #define BCM6328_LED_DEF_DELAY		500
27 
28 #define BCM6328_LED_BLINK_DELAYS	2
29 #define BCM6328_LED_BLINK_MS		20
30 
31 #define BCM6328_LED_BLINK_MASK		0x3f
32 #define BCM6328_LED_BLINK1_SHIFT	0
33 #define BCM6328_LED_BLINK1_MASK		(BCM6328_LED_BLINK_MASK << \
34 					 BCM6328_LED_BLINK1_SHIFT)
35 #define BCM6328_LED_BLINK2_SHIFT	6
36 #define BCM6328_LED_BLINK2_MASK		(BCM6328_LED_BLINK_MASK << \
37 					 BCM6328_LED_BLINK2_SHIFT)
38 #define BCM6328_SERIAL_LED_EN		BIT(12)
39 #define BCM6328_SERIAL_LED_MUX		BIT(13)
40 #define BCM6328_SERIAL_LED_CLK_NPOL	BIT(14)
41 #define BCM6328_SERIAL_LED_DATA_PPOL	BIT(15)
42 #define BCM6328_SERIAL_LED_SHIFT_DIR	BIT(16)
43 #define BCM6328_LED_SHIFT_TEST		BIT(30)
44 #define BCM6328_LED_TEST		BIT(31)
45 #define BCM6328_INIT_MASK		(BCM6328_SERIAL_LED_EN | \
46 					 BCM6328_SERIAL_LED_MUX | \
47 					 BCM6328_SERIAL_LED_CLK_NPOL | \
48 					 BCM6328_SERIAL_LED_DATA_PPOL | \
49 					 BCM6328_SERIAL_LED_SHIFT_DIR)
50 
51 #define BCM6328_LED_MODE_MASK		3
52 #define BCM6328_LED_MODE_ON		0
53 #define BCM6328_LED_MODE_BLINK1		1
54 #define BCM6328_LED_MODE_BLINK2		2
55 #define BCM6328_LED_MODE_OFF		3
56 #define BCM6328_LED_SHIFT(X)		((X) << 1)
57 
58 /**
59  * struct bcm6328_led - state container for bcm6328 based LEDs
60  * @cdev: LED class device for this LED
61  * @mem: memory resource
62  * @lock: memory lock
63  * @pin: LED pin number
64  * @blink_leds: blinking LEDs
65  * @blink_delay: blinking delay
66  * @active_low: LED is active low
67  */
68 struct bcm6328_led {
69 	struct led_classdev cdev;
70 	void __iomem *mem;
71 	spinlock_t *lock;
72 	unsigned long pin;
73 	unsigned long *blink_leds;
74 	unsigned long *blink_delay;
75 	bool active_low;
76 };
77 
bcm6328_led_write(void __iomem * reg,unsigned long data)78 static void bcm6328_led_write(void __iomem *reg, unsigned long data)
79 {
80 #ifdef CONFIG_CPU_BIG_ENDIAN
81 	iowrite32be(data, reg);
82 #else
83 	writel(data, reg);
84 #endif
85 }
86 
bcm6328_led_read(void __iomem * reg)87 static unsigned long bcm6328_led_read(void __iomem *reg)
88 {
89 #ifdef CONFIG_CPU_BIG_ENDIAN
90 	return ioread32be(reg);
91 #else
92 	return readl(reg);
93 #endif
94 }
95 
96 /**
97  * LEDMode 64 bits / 24 LEDs
98  * bits [31:0] -> LEDs 8-23
99  * bits [47:32] -> LEDs 0-7
100  * bits [63:48] -> unused
101  */
bcm6328_pin2shift(unsigned long pin)102 static unsigned long bcm6328_pin2shift(unsigned long pin)
103 {
104 	if (pin < 8)
105 		return pin + 16; /* LEDs 0-7 (bits 47:32) */
106 	else
107 		return pin - 8; /* LEDs 8-23 (bits 31:0) */
108 }
109 
bcm6328_led_mode(struct bcm6328_led * led,unsigned long value)110 static void bcm6328_led_mode(struct bcm6328_led *led, unsigned long value)
111 {
112 	void __iomem *mode;
113 	unsigned long val, shift;
114 
115 	shift = bcm6328_pin2shift(led->pin);
116 	if (shift / 16)
117 		mode = led->mem + BCM6328_REG_MODE_HI;
118 	else
119 		mode = led->mem + BCM6328_REG_MODE_LO;
120 
121 	val = bcm6328_led_read(mode);
122 	val &= ~(BCM6328_LED_MODE_MASK << BCM6328_LED_SHIFT(shift % 16));
123 	val |= (value << BCM6328_LED_SHIFT(shift % 16));
124 	bcm6328_led_write(mode, val);
125 }
126 
bcm6328_led_set(struct led_classdev * led_cdev,enum led_brightness value)127 static void bcm6328_led_set(struct led_classdev *led_cdev,
128 			    enum led_brightness value)
129 {
130 	struct bcm6328_led *led =
131 		container_of(led_cdev, struct bcm6328_led, cdev);
132 	unsigned long flags;
133 
134 	spin_lock_irqsave(led->lock, flags);
135 
136 	/* Remove LED from cached HW blinking intervals */
137 	led->blink_leds[0] &= ~BIT(led->pin);
138 	led->blink_leds[1] &= ~BIT(led->pin);
139 
140 	/* Set LED on/off */
141 	if ((led->active_low && value == LED_OFF) ||
142 	    (!led->active_low && value != LED_OFF))
143 		bcm6328_led_mode(led, BCM6328_LED_MODE_ON);
144 	else
145 		bcm6328_led_mode(led, BCM6328_LED_MODE_OFF);
146 
147 	spin_unlock_irqrestore(led->lock, flags);
148 }
149 
bcm6328_blink_delay(unsigned long delay)150 static unsigned long bcm6328_blink_delay(unsigned long delay)
151 {
152 	unsigned long bcm6328_delay;
153 
154 	bcm6328_delay = delay + BCM6328_LED_BLINK_MS / 2;
155 	bcm6328_delay = bcm6328_delay / BCM6328_LED_BLINK_MS;
156 	if (bcm6328_delay == 0)
157 		bcm6328_delay = 1;
158 
159 	return bcm6328_delay;
160 }
161 
bcm6328_blink_set(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)162 static int bcm6328_blink_set(struct led_classdev *led_cdev,
163 			     unsigned long *delay_on, unsigned long *delay_off)
164 {
165 	struct bcm6328_led *led =
166 		container_of(led_cdev, struct bcm6328_led, cdev);
167 	unsigned long delay, flags;
168 	int rc;
169 
170 	if (!*delay_on)
171 		*delay_on = BCM6328_LED_DEF_DELAY;
172 	if (!*delay_off)
173 		*delay_off = BCM6328_LED_DEF_DELAY;
174 
175 	delay = bcm6328_blink_delay(*delay_on);
176 	if (delay != bcm6328_blink_delay(*delay_off)) {
177 		dev_dbg(led_cdev->dev,
178 			"fallback to soft blinking (delay_on != delay_off)\n");
179 		return -EINVAL;
180 	}
181 
182 	if (delay > BCM6328_LED_BLINK_MASK) {
183 		dev_dbg(led_cdev->dev,
184 			"fallback to soft blinking (delay > %ums)\n",
185 			BCM6328_LED_BLINK_MASK * BCM6328_LED_BLINK_MS);
186 		return -EINVAL;
187 	}
188 
189 	spin_lock_irqsave(led->lock, flags);
190 	/*
191 	 * Check if any of the two configurable HW blinking intervals is
192 	 * available:
193 	 *   1. No LEDs assigned to the HW blinking interval.
194 	 *   2. Only this LED is assigned to the HW blinking interval.
195 	 *   3. LEDs with the same delay assigned.
196 	 */
197 	if (led->blink_leds[0] == 0 ||
198 	    led->blink_leds[0] == BIT(led->pin) ||
199 	    led->blink_delay[0] == delay) {
200 		unsigned long val;
201 
202 		/* Add LED to the first HW blinking interval cache */
203 		led->blink_leds[0] |= BIT(led->pin);
204 
205 		/* Remove LED from the second HW blinking interval cache */
206 		led->blink_leds[1] &= ~BIT(led->pin);
207 
208 		/* Cache first HW blinking interval delay */
209 		led->blink_delay[0] = delay;
210 
211 		/* Update the delay for the first HW blinking interval */
212 		val = bcm6328_led_read(led->mem + BCM6328_REG_INIT);
213 		val &= ~BCM6328_LED_BLINK1_MASK;
214 		val |= (delay << BCM6328_LED_BLINK1_SHIFT);
215 		bcm6328_led_write(led->mem + BCM6328_REG_INIT, val);
216 
217 		/* Set the LED to first HW blinking interval */
218 		bcm6328_led_mode(led, BCM6328_LED_MODE_BLINK1);
219 
220 		rc = 0;
221 	} else if (led->blink_leds[1] == 0 ||
222 		   led->blink_leds[1] == BIT(led->pin) ||
223 		   led->blink_delay[1] == delay) {
224 		unsigned long val;
225 
226 		/* Remove LED from the first HW blinking interval */
227 		led->blink_leds[0] &= ~BIT(led->pin);
228 
229 		/* Add LED to the second HW blinking interval */
230 		led->blink_leds[1] |= BIT(led->pin);
231 
232 		/* Cache second HW blinking interval delay */
233 		led->blink_delay[1] = delay;
234 
235 		/* Update the delay for the second HW blinking interval */
236 		val = bcm6328_led_read(led->mem + BCM6328_REG_INIT);
237 		val &= ~BCM6328_LED_BLINK2_MASK;
238 		val |= (delay << BCM6328_LED_BLINK2_SHIFT);
239 		bcm6328_led_write(led->mem + BCM6328_REG_INIT, val);
240 
241 		/* Set the LED to second HW blinking interval */
242 		bcm6328_led_mode(led, BCM6328_LED_MODE_BLINK2);
243 
244 		rc = 0;
245 	} else {
246 		dev_dbg(led_cdev->dev,
247 			"fallback to soft blinking (delay already set)\n");
248 		rc = -EINVAL;
249 	}
250 	spin_unlock_irqrestore(led->lock, flags);
251 
252 	return rc;
253 }
254 
bcm6328_hwled(struct device * dev,struct device_node * nc,u32 reg,void __iomem * mem,spinlock_t * lock)255 static int bcm6328_hwled(struct device *dev, struct device_node *nc, u32 reg,
256 			 void __iomem *mem, spinlock_t *lock)
257 {
258 	int i, cnt;
259 	unsigned long flags, val;
260 
261 	spin_lock_irqsave(lock, flags);
262 	val = bcm6328_led_read(mem + BCM6328_REG_HWDIS);
263 	val &= ~BIT(reg);
264 	bcm6328_led_write(mem + BCM6328_REG_HWDIS, val);
265 	spin_unlock_irqrestore(lock, flags);
266 
267 	/* Only LEDs 0-7 can be activity/link controlled */
268 	if (reg >= 8)
269 		return 0;
270 
271 	cnt = of_property_count_elems_of_size(nc, "brcm,link-signal-sources",
272 					      sizeof(u32));
273 	for (i = 0; i < cnt; i++) {
274 		u32 sel;
275 		void __iomem *addr;
276 
277 		if (reg < 4)
278 			addr = mem + BCM6328_REG_LNKACTSEL_LO;
279 		else
280 			addr = mem + BCM6328_REG_LNKACTSEL_HI;
281 
282 		of_property_read_u32_index(nc, "brcm,link-signal-sources", i,
283 					   &sel);
284 
285 		if (reg / 4 != sel / 4) {
286 			dev_warn(dev, "invalid link signal source\n");
287 			continue;
288 		}
289 
290 		spin_lock_irqsave(lock, flags);
291 		val = bcm6328_led_read(addr);
292 		val |= (BIT(reg % 4) << (((sel % 4) * 4) + 16));
293 		bcm6328_led_write(addr, val);
294 		spin_unlock_irqrestore(lock, flags);
295 	}
296 
297 	cnt = of_property_count_elems_of_size(nc,
298 					      "brcm,activity-signal-sources",
299 					      sizeof(u32));
300 	for (i = 0; i < cnt; i++) {
301 		u32 sel;
302 		void __iomem *addr;
303 
304 		if (reg < 4)
305 			addr = mem + BCM6328_REG_LNKACTSEL_LO;
306 		else
307 			addr = mem + BCM6328_REG_LNKACTSEL_HI;
308 
309 		of_property_read_u32_index(nc, "brcm,activity-signal-sources",
310 					   i, &sel);
311 
312 		if (reg / 4 != sel / 4) {
313 			dev_warn(dev, "invalid activity signal source\n");
314 			continue;
315 		}
316 
317 		spin_lock_irqsave(lock, flags);
318 		val = bcm6328_led_read(addr);
319 		val |= (BIT(reg % 4) << ((sel % 4) * 4));
320 		bcm6328_led_write(addr, val);
321 		spin_unlock_irqrestore(lock, flags);
322 	}
323 
324 	return 0;
325 }
326 
bcm6328_led(struct device * dev,struct device_node * nc,u32 reg,void __iomem * mem,spinlock_t * lock,unsigned long * blink_leds,unsigned long * blink_delay)327 static int bcm6328_led(struct device *dev, struct device_node *nc, u32 reg,
328 		       void __iomem *mem, spinlock_t *lock,
329 		       unsigned long *blink_leds, unsigned long *blink_delay)
330 {
331 	struct led_init_data init_data = {};
332 	struct bcm6328_led *led;
333 	const char *state;
334 	int rc;
335 
336 	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
337 	if (!led)
338 		return -ENOMEM;
339 
340 	led->pin = reg;
341 	led->mem = mem;
342 	led->lock = lock;
343 	led->blink_leds = blink_leds;
344 	led->blink_delay = blink_delay;
345 
346 	if (of_property_read_bool(nc, "active-low"))
347 		led->active_low = true;
348 
349 	if (!of_property_read_string(nc, "default-state", &state)) {
350 		if (!strcmp(state, "on")) {
351 			led->cdev.brightness = LED_FULL;
352 		} else if (!strcmp(state, "keep")) {
353 			void __iomem *mode;
354 			unsigned long val, shift;
355 
356 			shift = bcm6328_pin2shift(led->pin);
357 			if (shift / 16)
358 				mode = mem + BCM6328_REG_MODE_HI;
359 			else
360 				mode = mem + BCM6328_REG_MODE_LO;
361 
362 			val = bcm6328_led_read(mode) >>
363 			      BCM6328_LED_SHIFT(shift % 16);
364 			val &= BCM6328_LED_MODE_MASK;
365 			if ((led->active_low && val == BCM6328_LED_MODE_OFF) ||
366 			    (!led->active_low && val == BCM6328_LED_MODE_ON))
367 				led->cdev.brightness = LED_FULL;
368 			else
369 				led->cdev.brightness = LED_OFF;
370 		} else {
371 			led->cdev.brightness = LED_OFF;
372 		}
373 	} else {
374 		led->cdev.brightness = LED_OFF;
375 	}
376 
377 	bcm6328_led_set(&led->cdev, led->cdev.brightness);
378 
379 	led->cdev.brightness_set = bcm6328_led_set;
380 	led->cdev.blink_set = bcm6328_blink_set;
381 	init_data.fwnode = of_fwnode_handle(nc);
382 
383 	rc = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
384 	if (rc < 0)
385 		return rc;
386 
387 	dev_dbg(dev, "registered LED %s\n", led->cdev.name);
388 
389 	return 0;
390 }
391 
bcm6328_leds_probe(struct platform_device * pdev)392 static int bcm6328_leds_probe(struct platform_device *pdev)
393 {
394 	struct device *dev = &pdev->dev;
395 	struct device_node *np = dev_of_node(&pdev->dev);
396 	struct device_node *child;
397 	void __iomem *mem;
398 	spinlock_t *lock; /* memory lock */
399 	unsigned long val, *blink_leds, *blink_delay;
400 
401 	mem = devm_platform_ioremap_resource(pdev, 0);
402 	if (IS_ERR(mem))
403 		return PTR_ERR(mem);
404 
405 	lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
406 	if (!lock)
407 		return -ENOMEM;
408 
409 	blink_leds = devm_kcalloc(dev, BCM6328_LED_BLINK_DELAYS,
410 				  sizeof(*blink_leds), GFP_KERNEL);
411 	if (!blink_leds)
412 		return -ENOMEM;
413 
414 	blink_delay = devm_kcalloc(dev, BCM6328_LED_BLINK_DELAYS,
415 				   sizeof(*blink_delay), GFP_KERNEL);
416 	if (!blink_delay)
417 		return -ENOMEM;
418 
419 	spin_lock_init(lock);
420 
421 	bcm6328_led_write(mem + BCM6328_REG_HWDIS, ~0);
422 	bcm6328_led_write(mem + BCM6328_REG_LNKACTSEL_HI, 0);
423 	bcm6328_led_write(mem + BCM6328_REG_LNKACTSEL_LO, 0);
424 
425 	val = bcm6328_led_read(mem + BCM6328_REG_INIT);
426 	val &= ~(BCM6328_INIT_MASK);
427 	if (of_property_read_bool(np, "brcm,serial-leds"))
428 		val |= BCM6328_SERIAL_LED_EN;
429 	if (of_property_read_bool(np, "brcm,serial-mux"))
430 		val |= BCM6328_SERIAL_LED_MUX;
431 	if (of_property_read_bool(np, "brcm,serial-clk-low"))
432 		val |= BCM6328_SERIAL_LED_CLK_NPOL;
433 	if (!of_property_read_bool(np, "brcm,serial-dat-low"))
434 		val |= BCM6328_SERIAL_LED_DATA_PPOL;
435 	if (!of_property_read_bool(np, "brcm,serial-shift-inv"))
436 		val |= BCM6328_SERIAL_LED_SHIFT_DIR;
437 	bcm6328_led_write(mem + BCM6328_REG_INIT, val);
438 
439 	for_each_available_child_of_node(np, child) {
440 		int rc;
441 		u32 reg;
442 
443 		if (of_property_read_u32(child, "reg", &reg))
444 			continue;
445 
446 		if (reg >= BCM6328_LED_MAX_COUNT) {
447 			dev_err(dev, "invalid LED (%u >= %d)\n", reg,
448 				BCM6328_LED_MAX_COUNT);
449 			continue;
450 		}
451 
452 		if (of_property_read_bool(child, "brcm,hardware-controlled"))
453 			rc = bcm6328_hwled(dev, child, reg, mem, lock);
454 		else
455 			rc = bcm6328_led(dev, child, reg, mem, lock,
456 					 blink_leds, blink_delay);
457 
458 		if (rc < 0) {
459 			of_node_put(child);
460 			return rc;
461 		}
462 	}
463 
464 	return 0;
465 }
466 
467 static const struct of_device_id bcm6328_leds_of_match[] = {
468 	{ .compatible = "brcm,bcm6328-leds", },
469 	{ },
470 };
471 MODULE_DEVICE_TABLE(of, bcm6328_leds_of_match);
472 
473 static struct platform_driver bcm6328_leds_driver = {
474 	.probe = bcm6328_leds_probe,
475 	.driver = {
476 		.name = "leds-bcm6328",
477 		.of_match_table = bcm6328_leds_of_match,
478 	},
479 };
480 
481 module_platform_driver(bcm6328_leds_driver);
482 
483 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
484 MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
485 MODULE_DESCRIPTION("LED driver for BCM6328 controllers");
486 MODULE_LICENSE("GPL v2");
487 MODULE_ALIAS("platform:leds-bcm6328");
488