1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2021-2023 Samuel Holland <samuel@sholland.org>
4 *
5 * Partly based on drivers/leds/leds-turris-omnia.c, which is:
6 * Copyright (c) 2020 by Marek Behún <kabel@kernel.org>
7 */
8
9#include <linux/bitfield.h>
10#include <linux/clk.h>
11#include <linux/delay.h>
12#include <linux/dma-mapping.h>
13#include <linux/dmaengine.h>
14#include <linux/interrupt.h>
15#include <linux/io.h>
16#include <linux/led-class-multicolor.h>
17#include <linux/leds.h>
18#include <linux/mod_devicetable.h>
19#include <linux/module.h>
20#include <linux/platform_device.h>
21#include <linux/pm.h>
22#include <linux/property.h>
23#include <linux/reset.h>
24#include <linux/spinlock.h>
25
26#define LEDC_CTRL_REG 0x0000
27#define LEDC_CTRL_REG_DATA_LENGTH GENMASK(28, 16)
28#define LEDC_CTRL_REG_RGB_MODE GENMASK(8, 6)
29#define LEDC_CTRL_REG_LEDC_EN BIT(0)
30#define LEDC_T01_TIMING_CTRL_REG 0x0004
31#define LEDC_T01_TIMING_CTRL_REG_T1H GENMASK(26, 21)
32#define LEDC_T01_TIMING_CTRL_REG_T1L GENMASK(20, 16)
33#define LEDC_T01_TIMING_CTRL_REG_T0H GENMASK(10, 6)
34#define LEDC_T01_TIMING_CTRL_REG_T0L GENMASK(5, 0)
35#define LEDC_RESET_TIMING_CTRL_REG 0x000c
36#define LEDC_RESET_TIMING_CTRL_REG_TR GENMASK(28, 16)
37#define LEDC_RESET_TIMING_CTRL_REG_LED_NUM GENMASK(9, 0)
38#define LEDC_DATA_REG 0x0014
39#define LEDC_DMA_CTRL_REG 0x0018
40#define LEDC_DMA_CTRL_REG_DMA_EN BIT(5)
41#define LEDC_DMA_CTRL_REG_FIFO_TRIG_LEVEL GENMASK(4, 0)
42#define LEDC_INT_CTRL_REG 0x001c
43#define LEDC_INT_CTRL_REG_GLOBAL_INT_EN BIT(5)
44#define LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN BIT(1)
45#define LEDC_INT_CTRL_REG_TRANS_FINISH_INT_EN BIT(0)
46#define LEDC_INT_STS_REG 0x0020
47#define LEDC_INT_STS_REG_FIFO_WLW GENMASK(15, 10)
48#define LEDC_INT_STS_REG_FIFO_CPUREQ_INT BIT(1)
49#define LEDC_INT_STS_REG_TRANS_FINISH_INT BIT(0)
50
51#define LEDC_FIFO_DEPTH 32U
52#define LEDC_MAX_LEDS 1024
53#define LEDC_CHANNELS_PER_LED 3 /* RGB */
54
55#define LEDS_TO_BYTES(n) ((n) * sizeof(u32))
56
57struct sun50i_a100_ledc_led {
58 struct led_classdev_mc mc_cdev;
59 struct mc_subled subled_info[LEDC_CHANNELS_PER_LED];
60 u32 addr;
61};
62
63#define to_ledc_led(mc) container_of(mc, struct sun50i_a100_ledc_led, mc_cdev)
64
65struct sun50i_a100_ledc_timing {
66 u32 t0h_ns;
67 u32 t0l_ns;
68 u32 t1h_ns;
69 u32 t1l_ns;
70 u32 treset_ns;
71};
72
73struct sun50i_a100_ledc {
74 struct device *dev;
75 void __iomem *base;
76 struct clk *bus_clk;
77 struct clk *mod_clk;
78 struct reset_control *reset;
79
80 u32 *buffer;
81 struct dma_chan *dma_chan;
82 dma_addr_t dma_handle;
83 unsigned int pio_length;
84 unsigned int pio_offset;
85
86 spinlock_t lock;
87 unsigned int next_length;
88 bool xfer_active;
89
90 u32 format;
91 struct sun50i_a100_ledc_timing timing;
92
93 u32 max_addr;
94 u32 num_leds;
95 struct sun50i_a100_ledc_led leds[] __counted_by(num_leds);
96};
97
98static int sun50i_a100_ledc_dma_xfer(struct sun50i_a100_ledc *priv, unsigned int length)
99{
100 struct dma_async_tx_descriptor *desc;
101 dma_cookie_t cookie;
102
103 desc = dmaengine_prep_slave_single(chan: priv->dma_chan, buf: priv->dma_handle,
104 LEDS_TO_BYTES(length), dir: DMA_MEM_TO_DEV, flags: 0);
105 if (!desc)
106 return -ENOMEM;
107
108 cookie = dmaengine_submit(desc);
109 if (dma_submit_error(cookie))
110 return -EIO;
111
112 dma_async_issue_pending(chan: priv->dma_chan);
113
114 return 0;
115}
116
117static void sun50i_a100_ledc_pio_xfer(struct sun50i_a100_ledc *priv, unsigned int fifo_used)
118{
119 unsigned int burst, length, offset;
120 u32 control;
121
122 length = priv->pio_length;
123 offset = priv->pio_offset;
124 burst = min(length, LEDC_FIFO_DEPTH - fifo_used);
125
126 iowrite32_rep(port: priv->base + LEDC_DATA_REG, buf: priv->buffer + offset, count: burst);
127
128 if (burst < length) {
129 priv->pio_length = length - burst;
130 priv->pio_offset = offset + burst;
131
132 if (!offset) {
133 control = readl(addr: priv->base + LEDC_INT_CTRL_REG);
134 control |= LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN;
135 writel(val: control, addr: priv->base + LEDC_INT_CTRL_REG);
136 }
137 } else {
138 /* Disable the request IRQ once all data is written. */
139 control = readl(addr: priv->base + LEDC_INT_CTRL_REG);
140 control &= ~LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN;
141 writel(val: control, addr: priv->base + LEDC_INT_CTRL_REG);
142 }
143}
144
145static void sun50i_a100_ledc_start_xfer(struct sun50i_a100_ledc *priv, unsigned int length)
146{
147 bool use_dma = false;
148 u32 control;
149
150 if (priv->dma_chan && length > LEDC_FIFO_DEPTH) {
151 int ret;
152
153 ret = sun50i_a100_ledc_dma_xfer(priv, length);
154 if (ret)
155 dev_warn(priv->dev, "Failed to set up DMA (%d), using PIO\n", ret);
156 else
157 use_dma = true;
158 }
159
160 /* The DMA trigger level must be at least the burst length. */
161 control = FIELD_PREP(LEDC_DMA_CTRL_REG_DMA_EN, use_dma) |
162 FIELD_PREP_CONST(LEDC_DMA_CTRL_REG_FIFO_TRIG_LEVEL, LEDC_FIFO_DEPTH / 2);
163 writel(val: control, addr: priv->base + LEDC_DMA_CTRL_REG);
164
165 control = readl(addr: priv->base + LEDC_CTRL_REG);
166 control &= ~LEDC_CTRL_REG_DATA_LENGTH;
167 control |= FIELD_PREP(LEDC_CTRL_REG_DATA_LENGTH, length) | LEDC_CTRL_REG_LEDC_EN;
168 writel(val: control, addr: priv->base + LEDC_CTRL_REG);
169
170 if (!use_dma) {
171 /* The FIFO is empty when starting a new transfer. */
172 unsigned int fifo_used = 0;
173
174 priv->pio_length = length;
175 priv->pio_offset = 0;
176
177 sun50i_a100_ledc_pio_xfer(priv, fifo_used);
178 }
179}
180
181static irqreturn_t sun50i_a100_ledc_irq(int irq, void *data)
182{
183 struct sun50i_a100_ledc *priv = data;
184 u32 status;
185
186 status = readl(addr: priv->base + LEDC_INT_STS_REG);
187
188 if (status & LEDC_INT_STS_REG_TRANS_FINISH_INT) {
189 unsigned int next_length;
190
191 spin_lock(lock: &priv->lock);
192
193 /* If another transfer is queued, dequeue and start it. */
194 next_length = priv->next_length;
195 if (next_length)
196 priv->next_length = 0;
197 else
198 priv->xfer_active = false;
199
200 spin_unlock(lock: &priv->lock);
201
202 if (next_length)
203 sun50i_a100_ledc_start_xfer(priv, length: next_length);
204 } else if (status & LEDC_INT_STS_REG_FIFO_CPUREQ_INT) {
205 /* Continue the current transfer. */
206 sun50i_a100_ledc_pio_xfer(priv, FIELD_GET(LEDC_INT_STS_REG_FIFO_WLW, status));
207 }
208
209 /* Clear the W1C status bits. */
210 writel(val: status, addr: priv->base + LEDC_INT_STS_REG);
211
212 return IRQ_HANDLED;
213}
214
215static void sun50i_a100_ledc_brightness_set(struct led_classdev *cdev,
216 enum led_brightness brightness)
217{
218 struct sun50i_a100_ledc *priv = dev_get_drvdata(dev: cdev->dev->parent);
219 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(led_cdev: cdev);
220 struct sun50i_a100_ledc_led *led = to_ledc_led(mc_cdev);
221 unsigned int next_length;
222 unsigned long flags;
223 bool xfer_active;
224
225 led_mc_calc_color_components(mcled_cdev: mc_cdev, brightness);
226
227 priv->buffer[led->addr] = led->subled_info[0].brightness << 16 |
228 led->subled_info[1].brightness << 8 |
229 led->subled_info[2].brightness;
230
231 spin_lock_irqsave(&priv->lock, flags);
232
233 /* Start, enqueue, or extend an enqueued transfer, as appropriate. */
234 next_length = max(priv->next_length, led->addr + 1);
235 xfer_active = priv->xfer_active;
236 if (xfer_active)
237 priv->next_length = next_length;
238 else
239 priv->xfer_active = true;
240
241 spin_unlock_irqrestore(lock: &priv->lock, flags);
242
243 if (!xfer_active)
244 sun50i_a100_ledc_start_xfer(priv, length: next_length);
245}
246
247static const char *const sun50i_a100_ledc_formats[] = {
248 "rgb", "rbg", "grb", "gbr", "brg", "bgr",
249};
250
251static int sun50i_a100_ledc_parse_format(struct device *dev,
252 struct sun50i_a100_ledc *priv)
253{
254 const char *format = "grb";
255 u32 i;
256
257 device_property_read_string(dev, propname: "allwinner,pixel-format", val: &format);
258
259 for (i = 0; i < ARRAY_SIZE(sun50i_a100_ledc_formats); i++) {
260 if (!strcmp(format, sun50i_a100_ledc_formats[i])) {
261 priv->format = i;
262 return 0;
263 }
264 }
265
266 return dev_err_probe(dev, err: -EINVAL, fmt: "Bad pixel format '%s'\n", format);
267}
268
269static void sun50i_a100_ledc_set_format(struct sun50i_a100_ledc *priv)
270{
271 u32 control;
272
273 control = readl(addr: priv->base + LEDC_CTRL_REG);
274 control &= ~LEDC_CTRL_REG_RGB_MODE;
275 control |= FIELD_PREP(LEDC_CTRL_REG_RGB_MODE, priv->format);
276 writel(val: control, addr: priv->base + LEDC_CTRL_REG);
277}
278
279static const struct sun50i_a100_ledc_timing sun50i_a100_ledc_default_timing = {
280 .t0h_ns = 336,
281 .t0l_ns = 840,
282 .t1h_ns = 882,
283 .t1l_ns = 294,
284 .treset_ns = 300000,
285};
286
287static int sun50i_a100_ledc_parse_timing(struct device *dev,
288 struct sun50i_a100_ledc *priv)
289{
290 struct sun50i_a100_ledc_timing *timing = &priv->timing;
291
292 *timing = sun50i_a100_ledc_default_timing;
293
294 device_property_read_u32(dev, propname: "allwinner,t0h-ns", val: &timing->t0h_ns);
295 device_property_read_u32(dev, propname: "allwinner,t0l-ns", val: &timing->t0l_ns);
296 device_property_read_u32(dev, propname: "allwinner,t1h-ns", val: &timing->t1h_ns);
297 device_property_read_u32(dev, propname: "allwinner,t1l-ns", val: &timing->t1l_ns);
298 device_property_read_u32(dev, propname: "allwinner,treset-ns", val: &timing->treset_ns);
299
300 return 0;
301}
302
303static void sun50i_a100_ledc_set_timing(struct sun50i_a100_ledc *priv)
304{
305 const struct sun50i_a100_ledc_timing *timing = &priv->timing;
306 unsigned long mod_freq = clk_get_rate(clk: priv->mod_clk);
307 u32 cycle_ns;
308 u32 control;
309
310 if (!mod_freq)
311 return;
312
313 cycle_ns = NSEC_PER_SEC / mod_freq;
314 control = FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T1H, timing->t1h_ns / cycle_ns) |
315 FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T1L, timing->t1l_ns / cycle_ns) |
316 FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T0H, timing->t0h_ns / cycle_ns) |
317 FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T0L, timing->t0l_ns / cycle_ns);
318 writel(val: control, addr: priv->base + LEDC_T01_TIMING_CTRL_REG);
319
320 control = FIELD_PREP(LEDC_RESET_TIMING_CTRL_REG_TR, timing->treset_ns / cycle_ns) |
321 FIELD_PREP(LEDC_RESET_TIMING_CTRL_REG_LED_NUM, priv->max_addr);
322 writel(val: control, addr: priv->base + LEDC_RESET_TIMING_CTRL_REG);
323}
324
325static int sun50i_a100_ledc_resume(struct device *dev)
326{
327 struct sun50i_a100_ledc *priv = dev_get_drvdata(dev);
328 int ret;
329
330 ret = reset_control_deassert(rstc: priv->reset);
331 if (ret)
332 return ret;
333
334 ret = clk_prepare_enable(clk: priv->bus_clk);
335 if (ret)
336 goto err_assert_reset;
337
338 ret = clk_prepare_enable(clk: priv->mod_clk);
339 if (ret)
340 goto err_disable_bus_clk;
341
342 sun50i_a100_ledc_set_format(priv);
343 sun50i_a100_ledc_set_timing(priv);
344
345 writel(LEDC_INT_CTRL_REG_GLOBAL_INT_EN | LEDC_INT_CTRL_REG_TRANS_FINISH_INT_EN,
346 addr: priv->base + LEDC_INT_CTRL_REG);
347
348 return 0;
349
350err_disable_bus_clk:
351 clk_disable_unprepare(clk: priv->bus_clk);
352err_assert_reset:
353 reset_control_assert(rstc: priv->reset);
354
355 return ret;
356}
357
358static int sun50i_a100_ledc_suspend(struct device *dev)
359{
360 struct sun50i_a100_ledc *priv = dev_get_drvdata(dev);
361
362 /* Wait for all transfers to complete. */
363 for (;;) {
364 unsigned long flags;
365 bool xfer_active;
366
367 spin_lock_irqsave(&priv->lock, flags);
368 xfer_active = priv->xfer_active;
369 spin_unlock_irqrestore(lock: &priv->lock, flags);
370 if (!xfer_active)
371 break;
372
373 msleep(msecs: 1);
374 }
375
376 clk_disable_unprepare(clk: priv->mod_clk);
377 clk_disable_unprepare(clk: priv->bus_clk);
378 reset_control_assert(rstc: priv->reset);
379
380 return 0;
381}
382
383static void sun50i_a100_ledc_dma_cleanup(void *data)
384{
385 struct sun50i_a100_ledc *priv = data;
386
387 dma_release_channel(chan: priv->dma_chan);
388}
389
390static int sun50i_a100_ledc_probe(struct platform_device *pdev)
391{
392 struct dma_slave_config dma_cfg = {};
393 struct led_init_data init_data = {};
394 struct sun50i_a100_ledc_led *led;
395 struct device *dev = &pdev->dev;
396 struct sun50i_a100_ledc *priv;
397 struct fwnode_handle *child;
398 struct resource *mem;
399 u32 max_addr = 0;
400 u32 num_leds = 0;
401 int irq, ret;
402
403 /*
404 * The maximum LED address must be known in sun50i_a100_ledc_resume() before
405 * class device registration, so parse and validate the subnodes up front.
406 */
407 device_for_each_child_node(dev, child) {
408 u32 addr, color;
409
410 ret = fwnode_property_read_u32(fwnode: child, propname: "reg", val: &addr);
411 if (ret || addr >= LEDC_MAX_LEDS) {
412 fwnode_handle_put(fwnode: child);
413 return dev_err_probe(dev, err: -EINVAL, fmt: "'reg' must be between 0 and %d\n",
414 LEDC_MAX_LEDS - 1);
415 }
416
417 ret = fwnode_property_read_u32(fwnode: child, propname: "color", val: &color);
418 if (ret || color != LED_COLOR_ID_RGB) {
419 fwnode_handle_put(fwnode: child);
420 return dev_err_probe(dev, err: -EINVAL, fmt: "'color' must be LED_COLOR_ID_RGB\n");
421 }
422
423 max_addr = max(max_addr, addr);
424 num_leds++;
425 }
426
427 if (!num_leds)
428 return -ENODEV;
429
430 priv = devm_kzalloc(dev, struct_size(priv, leds, num_leds), GFP_KERNEL);
431 if (!priv)
432 return -ENOMEM;
433
434 priv->dev = dev;
435 priv->max_addr = max_addr;
436 priv->num_leds = num_leds;
437 spin_lock_init(&priv->lock);
438 dev_set_drvdata(dev, data: priv);
439
440 ret = sun50i_a100_ledc_parse_format(dev, priv);
441 if (ret)
442 return ret;
443
444 ret = sun50i_a100_ledc_parse_timing(dev, priv);
445 if (ret)
446 return ret;
447
448 priv->base = devm_platform_get_and_ioremap_resource(pdev, index: 0, res: &mem);
449 if (IS_ERR(ptr: priv->base))
450 return PTR_ERR(ptr: priv->base);
451
452 priv->bus_clk = devm_clk_get(dev, id: "bus");
453 if (IS_ERR(ptr: priv->bus_clk))
454 return PTR_ERR(ptr: priv->bus_clk);
455
456 priv->mod_clk = devm_clk_get(dev, id: "mod");
457 if (IS_ERR(ptr: priv->mod_clk))
458 return PTR_ERR(ptr: priv->mod_clk);
459
460 priv->reset = devm_reset_control_get_exclusive(dev, NULL);
461 if (IS_ERR(ptr: priv->reset))
462 return PTR_ERR(ptr: priv->reset);
463
464 priv->dma_chan = dma_request_chan(dev, name: "tx");
465 if (IS_ERR(ptr: priv->dma_chan)) {
466 if (PTR_ERR(ptr: priv->dma_chan) != -ENODEV)
467 return PTR_ERR(ptr: priv->dma_chan);
468
469 priv->dma_chan = NULL;
470
471 priv->buffer = devm_kzalloc(dev, LEDS_TO_BYTES(LEDC_MAX_LEDS), GFP_KERNEL);
472 if (!priv->buffer)
473 return -ENOMEM;
474 } else {
475 ret = devm_add_action_or_reset(dev, sun50i_a100_ledc_dma_cleanup, priv);
476 if (ret)
477 return ret;
478
479 dma_cfg.dst_addr = mem->start + LEDC_DATA_REG;
480 dma_cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
481 dma_cfg.dst_maxburst = LEDC_FIFO_DEPTH / 2;
482
483 ret = dmaengine_slave_config(chan: priv->dma_chan, config: &dma_cfg);
484 if (ret)
485 return ret;
486
487 priv->buffer = dmam_alloc_attrs(dev: dmaengine_get_dma_device(chan: priv->dma_chan),
488 LEDS_TO_BYTES(LEDC_MAX_LEDS), dma_handle: &priv->dma_handle,
489 GFP_KERNEL, DMA_ATTR_WRITE_COMBINE);
490 if (!priv->buffer)
491 return -ENOMEM;
492 }
493
494 irq = platform_get_irq(pdev, 0);
495 if (irq < 0)
496 return irq;
497
498 ret = devm_request_irq(dev, irq, handler: sun50i_a100_ledc_irq, irqflags: 0, devname: dev_name(dev), dev_id: priv);
499 if (ret)
500 return ret;
501
502 ret = sun50i_a100_ledc_resume(dev);
503 if (ret)
504 return ret;
505
506 led = priv->leds;
507 device_for_each_child_node(dev, child) {
508 struct led_classdev *cdev;
509
510 /* The node was already validated above. */
511 fwnode_property_read_u32(fwnode: child, propname: "reg", val: &led->addr);
512
513 led->subled_info[0].color_index = LED_COLOR_ID_RED;
514 led->subled_info[0].channel = 0;
515 led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
516 led->subled_info[1].channel = 1;
517 led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
518 led->subled_info[2].channel = 2;
519
520 led->mc_cdev.num_colors = ARRAY_SIZE(led->subled_info);
521 led->mc_cdev.subled_info = led->subled_info;
522
523 cdev = &led->mc_cdev.led_cdev;
524 cdev->max_brightness = U8_MAX;
525 cdev->brightness_set = sun50i_a100_ledc_brightness_set;
526
527 init_data.fwnode = child;
528
529 ret = led_classdev_multicolor_register_ext(parent: dev, mcled_cdev: &led->mc_cdev, init_data: &init_data);
530 if (ret) {
531 dev_err_probe(dev, err: ret, fmt: "Failed to register multicolor LED %u", led->addr);
532 goto err_put_child;
533 }
534
535 led++;
536 }
537
538 dev_info(dev, "Registered %u LEDs\n", num_leds);
539
540 return 0;
541
542err_put_child:
543 fwnode_handle_put(fwnode: child);
544 while (led-- > priv->leds)
545 led_classdev_multicolor_unregister(mcled_cdev: &led->mc_cdev);
546 sun50i_a100_ledc_suspend(dev: &pdev->dev);
547
548 return ret;
549}
550
551static void sun50i_a100_ledc_remove(struct platform_device *pdev)
552{
553 struct sun50i_a100_ledc *priv = platform_get_drvdata(pdev);
554
555 for (u32 i = 0; i < priv->num_leds; i++)
556 led_classdev_multicolor_unregister(mcled_cdev: &priv->leds[i].mc_cdev);
557 sun50i_a100_ledc_suspend(dev: &pdev->dev);
558}
559
560static const struct of_device_id sun50i_a100_ledc_of_match[] = {
561 { .compatible = "allwinner,sun50i-a100-ledc" },
562 {}
563};
564MODULE_DEVICE_TABLE(of, sun50i_a100_ledc_of_match);
565
566static DEFINE_SIMPLE_DEV_PM_OPS(sun50i_a100_ledc_pm,
567 sun50i_a100_ledc_suspend,
568 sun50i_a100_ledc_resume);
569
570static struct platform_driver sun50i_a100_ledc_driver = {
571 .probe = sun50i_a100_ledc_probe,
572 .remove_new = sun50i_a100_ledc_remove,
573 .shutdown = sun50i_a100_ledc_remove,
574 .driver = {
575 .name = "sun50i-a100-ledc",
576 .of_match_table = sun50i_a100_ledc_of_match,
577 .pm = pm_ptr(&sun50i_a100_ledc_pm),
578 },
579};
580module_platform_driver(sun50i_a100_ledc_driver);
581
582MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
583MODULE_DESCRIPTION("Allwinner A100 LED controller driver");
584MODULE_LICENSE("GPL");
585

source code of linux/drivers/leds/leds-sun50i-a100.c