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
57 struct 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
65 struct 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
73 struct 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
sun50i_a100_ledc_dma_xfer(struct sun50i_a100_ledc * priv,unsigned int length)98 static 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(priv->dma_chan, priv->dma_handle,
104 LEDS_TO_BYTES(length), DMA_MEM_TO_DEV, 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(priv->dma_chan);
113
114 return 0;
115 }
116
sun50i_a100_ledc_pio_xfer(struct sun50i_a100_ledc * priv,unsigned int fifo_used)117 static 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(priv->base + LEDC_DATA_REG, priv->buffer + offset, 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(priv->base + LEDC_INT_CTRL_REG);
134 control |= LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN;
135 writel(control, priv->base + LEDC_INT_CTRL_REG);
136 }
137 } else {
138 /* Disable the request IRQ once all data is written. */
139 control = readl(priv->base + LEDC_INT_CTRL_REG);
140 control &= ~LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN;
141 writel(control, priv->base + LEDC_INT_CTRL_REG);
142 }
143 }
144
sun50i_a100_ledc_start_xfer(struct sun50i_a100_ledc * priv,unsigned int length)145 static 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(control, priv->base + LEDC_DMA_CTRL_REG);
164
165 control = readl(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(control, 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
sun50i_a100_ledc_irq(int irq,void * data)181 static 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(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(&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(&priv->lock);
201
202 if (next_length)
203 sun50i_a100_ledc_start_xfer(priv, 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(status, priv->base + LEDC_INT_STS_REG);
211
212 return IRQ_HANDLED;
213 }
214
sun50i_a100_ledc_brightness_set(struct led_classdev * cdev,enum led_brightness brightness)215 static 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(cdev->dev->parent);
219 struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(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(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(&priv->lock, flags);
242
243 if (!xfer_active)
244 sun50i_a100_ledc_start_xfer(priv, next_length);
245 }
246
247 static const char *const sun50i_a100_ledc_formats[] = {
248 "rgb", "rbg", "grb", "gbr", "brg", "bgr",
249 };
250
sun50i_a100_ledc_parse_format(struct device * dev,struct sun50i_a100_ledc * priv)251 static int sun50i_a100_ledc_parse_format(struct device *dev,
252 struct sun50i_a100_ledc *priv)
253 {
254 const char *format = "grb";
255 int i;
256
257 device_property_read_string(dev, "allwinner,pixel-format", &format);
258
259 i = match_string(sun50i_a100_ledc_formats, ARRAY_SIZE(sun50i_a100_ledc_formats), format);
260 if (i < 0)
261 return dev_err_probe(dev, i, "Bad pixel format '%s'\n", format);
262
263 priv->format = i;
264 return 0;
265 }
266
sun50i_a100_ledc_set_format(struct sun50i_a100_ledc * priv)267 static void sun50i_a100_ledc_set_format(struct sun50i_a100_ledc *priv)
268 {
269 u32 control;
270
271 control = readl(priv->base + LEDC_CTRL_REG);
272 control &= ~LEDC_CTRL_REG_RGB_MODE;
273 control |= FIELD_PREP(LEDC_CTRL_REG_RGB_MODE, priv->format);
274 writel(control, priv->base + LEDC_CTRL_REG);
275 }
276
277 static const struct sun50i_a100_ledc_timing sun50i_a100_ledc_default_timing = {
278 .t0h_ns = 336,
279 .t0l_ns = 840,
280 .t1h_ns = 882,
281 .t1l_ns = 294,
282 .treset_ns = 300000,
283 };
284
sun50i_a100_ledc_parse_timing(struct device * dev,struct sun50i_a100_ledc * priv)285 static int sun50i_a100_ledc_parse_timing(struct device *dev,
286 struct sun50i_a100_ledc *priv)
287 {
288 struct sun50i_a100_ledc_timing *timing = &priv->timing;
289
290 *timing = sun50i_a100_ledc_default_timing;
291
292 device_property_read_u32(dev, "allwinner,t0h-ns", &timing->t0h_ns);
293 device_property_read_u32(dev, "allwinner,t0l-ns", &timing->t0l_ns);
294 device_property_read_u32(dev, "allwinner,t1h-ns", &timing->t1h_ns);
295 device_property_read_u32(dev, "allwinner,t1l-ns", &timing->t1l_ns);
296 device_property_read_u32(dev, "allwinner,treset-ns", &timing->treset_ns);
297
298 return 0;
299 }
300
sun50i_a100_ledc_set_timing(struct sun50i_a100_ledc * priv)301 static void sun50i_a100_ledc_set_timing(struct sun50i_a100_ledc *priv)
302 {
303 const struct sun50i_a100_ledc_timing *timing = &priv->timing;
304 unsigned long mod_freq = clk_get_rate(priv->mod_clk);
305 u32 cycle_ns;
306 u32 control;
307
308 if (!mod_freq)
309 return;
310
311 cycle_ns = NSEC_PER_SEC / mod_freq;
312 control = FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T1H, timing->t1h_ns / cycle_ns) |
313 FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T1L, timing->t1l_ns / cycle_ns) |
314 FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T0H, timing->t0h_ns / cycle_ns) |
315 FIELD_PREP(LEDC_T01_TIMING_CTRL_REG_T0L, timing->t0l_ns / cycle_ns);
316 writel(control, priv->base + LEDC_T01_TIMING_CTRL_REG);
317
318 control = FIELD_PREP(LEDC_RESET_TIMING_CTRL_REG_TR, timing->treset_ns / cycle_ns) |
319 FIELD_PREP(LEDC_RESET_TIMING_CTRL_REG_LED_NUM, priv->max_addr);
320 writel(control, priv->base + LEDC_RESET_TIMING_CTRL_REG);
321 }
322
sun50i_a100_ledc_resume(struct device * dev)323 static int sun50i_a100_ledc_resume(struct device *dev)
324 {
325 struct sun50i_a100_ledc *priv = dev_get_drvdata(dev);
326 int ret;
327
328 ret = reset_control_deassert(priv->reset);
329 if (ret)
330 return ret;
331
332 ret = clk_prepare_enable(priv->bus_clk);
333 if (ret)
334 goto err_assert_reset;
335
336 ret = clk_prepare_enable(priv->mod_clk);
337 if (ret)
338 goto err_disable_bus_clk;
339
340 sun50i_a100_ledc_set_format(priv);
341 sun50i_a100_ledc_set_timing(priv);
342
343 writel(LEDC_INT_CTRL_REG_GLOBAL_INT_EN | LEDC_INT_CTRL_REG_TRANS_FINISH_INT_EN,
344 priv->base + LEDC_INT_CTRL_REG);
345
346 return 0;
347
348 err_disable_bus_clk:
349 clk_disable_unprepare(priv->bus_clk);
350 err_assert_reset:
351 reset_control_assert(priv->reset);
352
353 return ret;
354 }
355
sun50i_a100_ledc_suspend(struct device * dev)356 static int sun50i_a100_ledc_suspend(struct device *dev)
357 {
358 struct sun50i_a100_ledc *priv = dev_get_drvdata(dev);
359
360 /* Wait for all transfers to complete. */
361 for (;;) {
362 unsigned long flags;
363 bool xfer_active;
364
365 spin_lock_irqsave(&priv->lock, flags);
366 xfer_active = priv->xfer_active;
367 spin_unlock_irqrestore(&priv->lock, flags);
368 if (!xfer_active)
369 break;
370
371 usleep_range(1000, 1100);
372 }
373
374 clk_disable_unprepare(priv->mod_clk);
375 clk_disable_unprepare(priv->bus_clk);
376 reset_control_assert(priv->reset);
377
378 return 0;
379 }
380
sun50i_a100_ledc_dma_cleanup(void * data)381 static void sun50i_a100_ledc_dma_cleanup(void *data)
382 {
383 struct sun50i_a100_ledc *priv = data;
384
385 dma_release_channel(priv->dma_chan);
386 }
387
sun50i_a100_ledc_probe(struct platform_device * pdev)388 static int sun50i_a100_ledc_probe(struct platform_device *pdev)
389 {
390 struct dma_slave_config dma_cfg = {};
391 struct led_init_data init_data = {};
392 struct sun50i_a100_ledc_led *led;
393 struct device *dev = &pdev->dev;
394 struct sun50i_a100_ledc *priv;
395 struct resource *mem;
396 u32 max_addr = 0;
397 u32 num_leds = 0;
398 int irq, ret;
399
400 /*
401 * The maximum LED address must be known in sun50i_a100_ledc_resume() before
402 * class device registration, so parse and validate the subnodes up front.
403 */
404 device_for_each_child_node_scoped(dev, child) {
405 u32 addr, color;
406
407 ret = fwnode_property_read_u32(child, "reg", &addr);
408 if (ret || addr >= LEDC_MAX_LEDS)
409 return dev_err_probe(dev, -EINVAL, "'reg' must be between 0 and %d\n",
410 LEDC_MAX_LEDS - 1);
411
412 ret = fwnode_property_read_u32(child, "color", &color);
413 if (ret || color != LED_COLOR_ID_RGB)
414 return dev_err_probe(dev, -EINVAL, "'color' must be LED_COLOR_ID_RGB\n");
415
416 max_addr = max(max_addr, addr);
417 num_leds++;
418 }
419
420 if (!num_leds)
421 return -ENODEV;
422
423 priv = devm_kzalloc(dev, struct_size(priv, leds, num_leds), GFP_KERNEL);
424 if (!priv)
425 return -ENOMEM;
426
427 priv->dev = dev;
428 priv->max_addr = max_addr;
429 priv->num_leds = num_leds;
430 spin_lock_init(&priv->lock);
431 dev_set_drvdata(dev, priv);
432
433 ret = sun50i_a100_ledc_parse_format(dev, priv);
434 if (ret)
435 return ret;
436
437 ret = sun50i_a100_ledc_parse_timing(dev, priv);
438 if (ret)
439 return ret;
440
441 priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
442 if (IS_ERR(priv->base))
443 return PTR_ERR(priv->base);
444
445 priv->bus_clk = devm_clk_get(dev, "bus");
446 if (IS_ERR(priv->bus_clk))
447 return PTR_ERR(priv->bus_clk);
448
449 priv->mod_clk = devm_clk_get(dev, "mod");
450 if (IS_ERR(priv->mod_clk))
451 return PTR_ERR(priv->mod_clk);
452
453 priv->reset = devm_reset_control_get_exclusive(dev, NULL);
454 if (IS_ERR(priv->reset))
455 return PTR_ERR(priv->reset);
456
457 priv->dma_chan = dma_request_chan(dev, "tx");
458 if (IS_ERR(priv->dma_chan)) {
459 if (PTR_ERR(priv->dma_chan) != -ENODEV)
460 return PTR_ERR(priv->dma_chan);
461
462 priv->dma_chan = NULL;
463
464 priv->buffer = devm_kzalloc(dev, LEDS_TO_BYTES(LEDC_MAX_LEDS), GFP_KERNEL);
465 if (!priv->buffer)
466 return -ENOMEM;
467 } else {
468 ret = devm_add_action_or_reset(dev, sun50i_a100_ledc_dma_cleanup, priv);
469 if (ret)
470 return ret;
471
472 dma_cfg.dst_addr = mem->start + LEDC_DATA_REG;
473 dma_cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
474 dma_cfg.dst_maxburst = LEDC_FIFO_DEPTH / 2;
475
476 ret = dmaengine_slave_config(priv->dma_chan, &dma_cfg);
477 if (ret)
478 return ret;
479
480 priv->buffer = dmam_alloc_attrs(dmaengine_get_dma_device(priv->dma_chan),
481 LEDS_TO_BYTES(LEDC_MAX_LEDS), &priv->dma_handle,
482 GFP_KERNEL, DMA_ATTR_WRITE_COMBINE);
483 if (!priv->buffer)
484 return -ENOMEM;
485 }
486
487 irq = platform_get_irq(pdev, 0);
488 if (irq < 0)
489 return irq;
490
491 ret = devm_request_irq(dev, irq, sun50i_a100_ledc_irq, 0, dev_name(dev), priv);
492 if (ret)
493 return ret;
494
495 ret = sun50i_a100_ledc_resume(dev);
496 if (ret)
497 return ret;
498
499 led = priv->leds;
500 device_for_each_child_node_scoped(dev, child) {
501 struct led_classdev *cdev;
502
503 /* The node was already validated above. */
504 fwnode_property_read_u32(child, "reg", &led->addr);
505
506 led->subled_info[0].color_index = LED_COLOR_ID_RED;
507 led->subled_info[0].channel = 0;
508 led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
509 led->subled_info[1].channel = 1;
510 led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
511 led->subled_info[2].channel = 2;
512
513 led->mc_cdev.num_colors = ARRAY_SIZE(led->subled_info);
514 led->mc_cdev.subled_info = led->subled_info;
515
516 cdev = &led->mc_cdev.led_cdev;
517 cdev->max_brightness = U8_MAX;
518 cdev->brightness_set = sun50i_a100_ledc_brightness_set;
519
520 init_data.fwnode = child;
521
522 ret = led_classdev_multicolor_register_ext(dev, &led->mc_cdev, &init_data);
523 if (ret) {
524 dev_err_probe(dev, ret, "Failed to register multicolor LED %u", led->addr);
525 while (led-- > priv->leds)
526 led_classdev_multicolor_unregister(&led->mc_cdev);
527 sun50i_a100_ledc_suspend(&pdev->dev);
528
529 return ret;
530 }
531
532 led++;
533 }
534
535 dev_info(dev, "Registered %u LEDs\n", num_leds);
536
537 return 0;
538 }
539
sun50i_a100_ledc_remove(struct platform_device * pdev)540 static void sun50i_a100_ledc_remove(struct platform_device *pdev)
541 {
542 struct sun50i_a100_ledc *priv = platform_get_drvdata(pdev);
543
544 for (u32 i = 0; i < priv->num_leds; i++)
545 led_classdev_multicolor_unregister(&priv->leds[i].mc_cdev);
546 sun50i_a100_ledc_suspend(&pdev->dev);
547 }
548
549 static const struct of_device_id sun50i_a100_ledc_of_match[] = {
550 { .compatible = "allwinner,sun50i-a100-ledc" },
551 {}
552 };
553 MODULE_DEVICE_TABLE(of, sun50i_a100_ledc_of_match);
554
555 static DEFINE_SIMPLE_DEV_PM_OPS(sun50i_a100_ledc_pm,
556 sun50i_a100_ledc_suspend,
557 sun50i_a100_ledc_resume);
558
559 static struct platform_driver sun50i_a100_ledc_driver = {
560 .probe = sun50i_a100_ledc_probe,
561 .remove = sun50i_a100_ledc_remove,
562 .shutdown = sun50i_a100_ledc_remove,
563 .driver = {
564 .name = "sun50i-a100-ledc",
565 .of_match_table = sun50i_a100_ledc_of_match,
566 .pm = pm_ptr(&sun50i_a100_ledc_pm),
567 },
568 };
569 module_platform_driver(sun50i_a100_ledc_driver);
570
571 MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
572 MODULE_DESCRIPTION("Allwinner A100 LED controller driver");
573 MODULE_LICENSE("GPL");
574