1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Rockchip Successive Approximation Register (SAR) A/D Converter
4  * Copyright (C) 2014 ROCKCHIP, Inc.
5  */
6 
7 #include <linux/bitfield.h>
8 #include <linux/module.h>
9 #include <linux/mutex.h>
10 #include <linux/platform_device.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/of.h>
14 #include <linux/clk.h>
15 #include <linux/completion.h>
16 #include <linux/delay.h>
17 #include <linux/reset.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/trigger_consumer.h>
22 #include <linux/iio/triggered_buffer.h>
23 
24 #define SARADC_DATA			0x00
25 
26 #define SARADC_STAS			0x04
27 #define SARADC_STAS_BUSY		BIT(0)
28 
29 #define SARADC_CTRL			0x08
30 #define SARADC_CTRL_IRQ_STATUS		BIT(6)
31 #define SARADC_CTRL_IRQ_ENABLE		BIT(5)
32 #define SARADC_CTRL_POWER_CTRL		BIT(3)
33 #define SARADC_CTRL_CHN_MASK		0x7
34 
35 #define SARADC_DLY_PU_SOC		0x0c
36 #define SARADC_DLY_PU_SOC_MASK		0x3f
37 
38 #define SARADC_TIMEOUT			msecs_to_jiffies(100)
39 #define SARADC_MAX_CHANNELS		8
40 
41 /* v2 registers */
42 #define SARADC2_CONV_CON		0x000
43 #define SARADC_T_PD_SOC			0x004
44 #define SARADC_T_DAS_SOC		0x00c
45 #define SARADC2_END_INT_EN		0x104
46 #define SARADC2_ST_CON			0x108
47 #define SARADC2_STATUS			0x10c
48 #define SARADC2_END_INT_ST		0x110
49 #define SARADC2_DATA_BASE		0x120
50 
51 #define SARADC2_EN_END_INT		BIT(0)
52 #define SARADC2_START			BIT(4)
53 #define SARADC2_SINGLE_MODE		BIT(5)
54 
55 #define SARADC2_CONV_CHANNELS GENMASK(3, 0)
56 
57 struct rockchip_saradc;
58 
59 struct rockchip_saradc_data {
60 	const struct iio_chan_spec	*channels;
61 	int				num_channels;
62 	unsigned long			clk_rate;
63 	void (*start)(struct rockchip_saradc *info, int chn);
64 	int (*read)(struct rockchip_saradc *info);
65 	void (*power_down)(struct rockchip_saradc *info);
66 };
67 
68 struct rockchip_saradc {
69 	void __iomem		*regs;
70 	struct clk		*pclk;
71 	struct clk		*clk;
72 	struct completion	completion;
73 	struct regulator	*vref;
74 	/* lock to protect against multiple access to the device */
75 	struct mutex		lock;
76 	int			uv_vref;
77 	struct reset_control	*reset;
78 	const struct rockchip_saradc_data *data;
79 	u16			last_val;
80 	const struct iio_chan_spec *last_chan;
81 	struct notifier_block nb;
82 };
83 
84 static void rockchip_saradc_reset_controller(struct reset_control *reset);
85 
86 static void rockchip_saradc_start_v1(struct rockchip_saradc *info, int chn)
87 {
88 	/* 8 clock periods as delay between power up and start cmd */
89 	writel_relaxed(8, info->regs + SARADC_DLY_PU_SOC);
90 	/* Select the channel to be used and trigger conversion */
91 	writel(SARADC_CTRL_POWER_CTRL | (chn & SARADC_CTRL_CHN_MASK) |
92 	       SARADC_CTRL_IRQ_ENABLE, info->regs + SARADC_CTRL);
93 }
94 
95 static void rockchip_saradc_start_v2(struct rockchip_saradc *info, int chn)
96 {
97 	int val;
98 
99 	if (info->reset)
100 		rockchip_saradc_reset_controller(info->reset);
101 
102 	writel_relaxed(0xc, info->regs + SARADC_T_DAS_SOC);
103 	writel_relaxed(0x20, info->regs + SARADC_T_PD_SOC);
104 	val = FIELD_PREP(SARADC2_EN_END_INT, 1);
105 	val |= SARADC2_EN_END_INT << 16;
106 	writel_relaxed(val, info->regs + SARADC2_END_INT_EN);
107 	val = FIELD_PREP(SARADC2_START, 1) |
108 	      FIELD_PREP(SARADC2_SINGLE_MODE, 1) |
109 	      FIELD_PREP(SARADC2_CONV_CHANNELS, chn);
110 	val |= (SARADC2_START | SARADC2_SINGLE_MODE | SARADC2_CONV_CHANNELS) << 16;
111 	writel(val, info->regs + SARADC2_CONV_CON);
112 }
113 
114 static void rockchip_saradc_start(struct rockchip_saradc *info, int chn)
115 {
116 	info->data->start(info, chn);
117 }
118 
119 static int rockchip_saradc_read_v1(struct rockchip_saradc *info)
120 {
121 	return readl_relaxed(info->regs + SARADC_DATA);
122 }
123 
124 static int rockchip_saradc_read_v2(struct rockchip_saradc *info)
125 {
126 	int offset;
127 
128 	/* Clear irq */
129 	writel_relaxed(0x1, info->regs + SARADC2_END_INT_ST);
130 
131 	offset = SARADC2_DATA_BASE + info->last_chan->channel * 0x4;
132 
133 	return readl_relaxed(info->regs + offset);
134 }
135 
136 static int rockchip_saradc_read(struct rockchip_saradc *info)
137 {
138 	return info->data->read(info);
139 }
140 
141 static void rockchip_saradc_power_down_v1(struct rockchip_saradc *info)
142 {
143 	writel_relaxed(0, info->regs + SARADC_CTRL);
144 }
145 
146 static void rockchip_saradc_power_down(struct rockchip_saradc *info)
147 {
148 	if (info->data->power_down)
149 		info->data->power_down(info);
150 }
151 
152 static int rockchip_saradc_conversion(struct rockchip_saradc *info,
153 				      struct iio_chan_spec const *chan)
154 {
155 	reinit_completion(&info->completion);
156 
157 	info->last_chan = chan;
158 	rockchip_saradc_start(info, chan->channel);
159 
160 	if (!wait_for_completion_timeout(&info->completion, SARADC_TIMEOUT))
161 		return -ETIMEDOUT;
162 
163 	return 0;
164 }
165 
166 static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
167 				    struct iio_chan_spec const *chan,
168 				    int *val, int *val2, long mask)
169 {
170 	struct rockchip_saradc *info = iio_priv(indio_dev);
171 	int ret;
172 
173 	switch (mask) {
174 	case IIO_CHAN_INFO_RAW:
175 		mutex_lock(&info->lock);
176 
177 		ret = rockchip_saradc_conversion(info, chan);
178 		if (ret) {
179 			rockchip_saradc_power_down(info);
180 			mutex_unlock(&info->lock);
181 			return ret;
182 		}
183 
184 		*val = info->last_val;
185 		mutex_unlock(&info->lock);
186 		return IIO_VAL_INT;
187 	case IIO_CHAN_INFO_SCALE:
188 		*val = info->uv_vref / 1000;
189 		*val2 = chan->scan_type.realbits;
190 		return IIO_VAL_FRACTIONAL_LOG2;
191 	default:
192 		return -EINVAL;
193 	}
194 }
195 
196 static irqreturn_t rockchip_saradc_isr(int irq, void *dev_id)
197 {
198 	struct rockchip_saradc *info = dev_id;
199 
200 	/* Read value */
201 	info->last_val = rockchip_saradc_read(info);
202 	info->last_val &= GENMASK(info->last_chan->scan_type.realbits - 1, 0);
203 
204 	rockchip_saradc_power_down(info);
205 
206 	complete(&info->completion);
207 
208 	return IRQ_HANDLED;
209 }
210 
211 static const struct iio_info rockchip_saradc_iio_info = {
212 	.read_raw = rockchip_saradc_read_raw,
213 };
214 
215 #define SARADC_CHANNEL(_index, _id, _res) {			\
216 	.type = IIO_VOLTAGE,					\
217 	.indexed = 1,						\
218 	.channel = _index,					\
219 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
220 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
221 	.datasheet_name = _id,					\
222 	.scan_index = _index,					\
223 	.scan_type = {						\
224 		.sign = 'u',					\
225 		.realbits = _res,				\
226 		.storagebits = 16,				\
227 		.endianness = IIO_CPU,				\
228 	},							\
229 }
230 
231 static const struct iio_chan_spec rockchip_saradc_iio_channels[] = {
232 	SARADC_CHANNEL(0, "adc0", 10),
233 	SARADC_CHANNEL(1, "adc1", 10),
234 	SARADC_CHANNEL(2, "adc2", 10),
235 };
236 
237 static const struct rockchip_saradc_data saradc_data = {
238 	.channels = rockchip_saradc_iio_channels,
239 	.num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels),
240 	.clk_rate = 1000000,
241 	.start = rockchip_saradc_start_v1,
242 	.read = rockchip_saradc_read_v1,
243 	.power_down = rockchip_saradc_power_down_v1,
244 };
245 
246 static const struct iio_chan_spec rockchip_rk3066_tsadc_iio_channels[] = {
247 	SARADC_CHANNEL(0, "adc0", 12),
248 	SARADC_CHANNEL(1, "adc1", 12),
249 };
250 
251 static const struct rockchip_saradc_data rk3066_tsadc_data = {
252 	.channels = rockchip_rk3066_tsadc_iio_channels,
253 	.num_channels = ARRAY_SIZE(rockchip_rk3066_tsadc_iio_channels),
254 	.clk_rate = 50000,
255 	.start = rockchip_saradc_start_v1,
256 	.read = rockchip_saradc_read_v1,
257 	.power_down = rockchip_saradc_power_down_v1,
258 };
259 
260 static const struct iio_chan_spec rockchip_rk3399_saradc_iio_channels[] = {
261 	SARADC_CHANNEL(0, "adc0", 10),
262 	SARADC_CHANNEL(1, "adc1", 10),
263 	SARADC_CHANNEL(2, "adc2", 10),
264 	SARADC_CHANNEL(3, "adc3", 10),
265 	SARADC_CHANNEL(4, "adc4", 10),
266 	SARADC_CHANNEL(5, "adc5", 10),
267 };
268 
269 static const struct rockchip_saradc_data rk3399_saradc_data = {
270 	.channels = rockchip_rk3399_saradc_iio_channels,
271 	.num_channels = ARRAY_SIZE(rockchip_rk3399_saradc_iio_channels),
272 	.clk_rate = 1000000,
273 	.start = rockchip_saradc_start_v1,
274 	.read = rockchip_saradc_read_v1,
275 	.power_down = rockchip_saradc_power_down_v1,
276 };
277 
278 static const struct iio_chan_spec rockchip_rk3568_saradc_iio_channels[] = {
279 	SARADC_CHANNEL(0, "adc0", 10),
280 	SARADC_CHANNEL(1, "adc1", 10),
281 	SARADC_CHANNEL(2, "adc2", 10),
282 	SARADC_CHANNEL(3, "adc3", 10),
283 	SARADC_CHANNEL(4, "adc4", 10),
284 	SARADC_CHANNEL(5, "adc5", 10),
285 	SARADC_CHANNEL(6, "adc6", 10),
286 	SARADC_CHANNEL(7, "adc7", 10),
287 };
288 
289 static const struct rockchip_saradc_data rk3568_saradc_data = {
290 	.channels = rockchip_rk3568_saradc_iio_channels,
291 	.num_channels = ARRAY_SIZE(rockchip_rk3568_saradc_iio_channels),
292 	.clk_rate = 1000000,
293 	.start = rockchip_saradc_start_v1,
294 	.read = rockchip_saradc_read_v1,
295 	.power_down = rockchip_saradc_power_down_v1,
296 };
297 
298 static const struct iio_chan_spec rockchip_rk3588_saradc_iio_channels[] = {
299 	SARADC_CHANNEL(0, "adc0", 12),
300 	SARADC_CHANNEL(1, "adc1", 12),
301 	SARADC_CHANNEL(2, "adc2", 12),
302 	SARADC_CHANNEL(3, "adc3", 12),
303 	SARADC_CHANNEL(4, "adc4", 12),
304 	SARADC_CHANNEL(5, "adc5", 12),
305 	SARADC_CHANNEL(6, "adc6", 12),
306 	SARADC_CHANNEL(7, "adc7", 12),
307 };
308 
309 static const struct rockchip_saradc_data rk3588_saradc_data = {
310 	.channels = rockchip_rk3588_saradc_iio_channels,
311 	.num_channels = ARRAY_SIZE(rockchip_rk3588_saradc_iio_channels),
312 	.clk_rate = 1000000,
313 	.start = rockchip_saradc_start_v2,
314 	.read = rockchip_saradc_read_v2,
315 };
316 
317 static const struct of_device_id rockchip_saradc_match[] = {
318 	{
319 		.compatible = "rockchip,saradc",
320 		.data = &saradc_data,
321 	}, {
322 		.compatible = "rockchip,rk3066-tsadc",
323 		.data = &rk3066_tsadc_data,
324 	}, {
325 		.compatible = "rockchip,rk3399-saradc",
326 		.data = &rk3399_saradc_data,
327 	}, {
328 		.compatible = "rockchip,rk3568-saradc",
329 		.data = &rk3568_saradc_data,
330 	}, {
331 		.compatible = "rockchip,rk3588-saradc",
332 		.data = &rk3588_saradc_data,
333 	},
334 	{},
335 };
336 MODULE_DEVICE_TABLE(of, rockchip_saradc_match);
337 
338 /*
339  * Reset SARADC Controller.
340  */
341 static void rockchip_saradc_reset_controller(struct reset_control *reset)
342 {
343 	reset_control_assert(reset);
344 	usleep_range(10, 20);
345 	reset_control_deassert(reset);
346 }
347 
348 static void rockchip_saradc_regulator_disable(void *data)
349 {
350 	struct rockchip_saradc *info = data;
351 
352 	regulator_disable(info->vref);
353 }
354 
355 static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p)
356 {
357 	struct iio_poll_func *pf = p;
358 	struct iio_dev *i_dev = pf->indio_dev;
359 	struct rockchip_saradc *info = iio_priv(i_dev);
360 	/*
361 	 * @values: each channel takes an u16 value
362 	 * @timestamp: will be 8-byte aligned automatically
363 	 */
364 	struct {
365 		u16 values[SARADC_MAX_CHANNELS];
366 		int64_t timestamp;
367 	} data;
368 	int ret;
369 	int i, j = 0;
370 
371 	mutex_lock(&info->lock);
372 
373 	for_each_set_bit(i, i_dev->active_scan_mask, i_dev->masklength) {
374 		const struct iio_chan_spec *chan = &i_dev->channels[i];
375 
376 		ret = rockchip_saradc_conversion(info, chan);
377 		if (ret) {
378 			rockchip_saradc_power_down(info);
379 			goto out;
380 		}
381 
382 		data.values[j] = info->last_val;
383 		j++;
384 	}
385 
386 	iio_push_to_buffers_with_timestamp(i_dev, &data, iio_get_time_ns(i_dev));
387 out:
388 	mutex_unlock(&info->lock);
389 
390 	iio_trigger_notify_done(i_dev->trig);
391 
392 	return IRQ_HANDLED;
393 }
394 
395 static int rockchip_saradc_volt_notify(struct notifier_block *nb,
396 				       unsigned long event, void *data)
397 {
398 	struct rockchip_saradc *info =
399 			container_of(nb, struct rockchip_saradc, nb);
400 
401 	if (event & REGULATOR_EVENT_VOLTAGE_CHANGE)
402 		info->uv_vref = (unsigned long)data;
403 
404 	return NOTIFY_OK;
405 }
406 
407 static void rockchip_saradc_regulator_unreg_notifier(void *data)
408 {
409 	struct rockchip_saradc *info = data;
410 
411 	regulator_unregister_notifier(info->vref, &info->nb);
412 }
413 
414 static int rockchip_saradc_probe(struct platform_device *pdev)
415 {
416 	const struct rockchip_saradc_data *match_data;
417 	struct rockchip_saradc *info = NULL;
418 	struct device_node *np = pdev->dev.of_node;
419 	struct iio_dev *indio_dev = NULL;
420 	int ret;
421 	int irq;
422 
423 	if (!np)
424 		return -ENODEV;
425 
426 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
427 	if (!indio_dev)
428 		return dev_err_probe(&pdev->dev, -ENOMEM,
429 				     "failed allocating iio device\n");
430 
431 	info = iio_priv(indio_dev);
432 
433 	match_data = of_device_get_match_data(&pdev->dev);
434 	if (!match_data)
435 		return dev_err_probe(&pdev->dev, -ENODEV,
436 				     "failed to match device\n");
437 
438 	info->data = match_data;
439 
440 	/* Sanity check for possible later IP variants with more channels */
441 	if (info->data->num_channels > SARADC_MAX_CHANNELS)
442 		return dev_err_probe(&pdev->dev, -EINVAL,
443 				     "max channels exceeded");
444 
445 	info->regs = devm_platform_ioremap_resource(pdev, 0);
446 	if (IS_ERR(info->regs))
447 		return PTR_ERR(info->regs);
448 
449 	/*
450 	 * The reset should be an optional property, as it should work
451 	 * with old devicetrees as well
452 	 */
453 	info->reset = devm_reset_control_get_exclusive(&pdev->dev,
454 						       "saradc-apb");
455 	if (IS_ERR(info->reset)) {
456 		ret = PTR_ERR(info->reset);
457 		if (ret != -ENOENT)
458 			return dev_err_probe(&pdev->dev, ret,
459 					     "failed to get saradc-apb\n");
460 
461 		dev_dbg(&pdev->dev, "no reset control found\n");
462 		info->reset = NULL;
463 	}
464 
465 	init_completion(&info->completion);
466 
467 	irq = platform_get_irq(pdev, 0);
468 	if (irq < 0)
469 		return irq;
470 
471 	ret = devm_request_irq(&pdev->dev, irq, rockchip_saradc_isr,
472 			       0, dev_name(&pdev->dev), info);
473 	if (ret < 0) {
474 		dev_err(&pdev->dev, "failed requesting irq %d\n", irq);
475 		return ret;
476 	}
477 
478 	info->vref = devm_regulator_get(&pdev->dev, "vref");
479 	if (IS_ERR(info->vref))
480 		return dev_err_probe(&pdev->dev, PTR_ERR(info->vref),
481 				     "failed to get regulator\n");
482 
483 	if (info->reset)
484 		rockchip_saradc_reset_controller(info->reset);
485 
486 	/*
487 	 * Use a default value for the converter clock.
488 	 * This may become user-configurable in the future.
489 	 */
490 	ret = clk_set_rate(info->clk, info->data->clk_rate);
491 	if (ret < 0)
492 		return dev_err_probe(&pdev->dev, ret,
493 				     "failed to set adc clk rate\n");
494 
495 	ret = regulator_enable(info->vref);
496 	if (ret < 0)
497 		return dev_err_probe(&pdev->dev, ret,
498 				     "failed to enable vref regulator\n");
499 
500 	ret = devm_add_action_or_reset(&pdev->dev,
501 				       rockchip_saradc_regulator_disable, info);
502 	if (ret)
503 		return dev_err_probe(&pdev->dev, ret,
504 				     "failed to register devm action\n");
505 
506 	ret = regulator_get_voltage(info->vref);
507 	if (ret < 0)
508 		return ret;
509 
510 	info->uv_vref = ret;
511 
512 	info->pclk = devm_clk_get_enabled(&pdev->dev, "apb_pclk");
513 	if (IS_ERR(info->pclk))
514 		return dev_err_probe(&pdev->dev, PTR_ERR(info->pclk),
515 				     "failed to get pclk\n");
516 
517 	info->clk = devm_clk_get_enabled(&pdev->dev, "saradc");
518 	if (IS_ERR(info->clk))
519 		return dev_err_probe(&pdev->dev, PTR_ERR(info->clk),
520 				     "failed to get adc clock\n");
521 
522 	platform_set_drvdata(pdev, indio_dev);
523 
524 	indio_dev->name = dev_name(&pdev->dev);
525 	indio_dev->info = &rockchip_saradc_iio_info;
526 	indio_dev->modes = INDIO_DIRECT_MODE;
527 
528 	indio_dev->channels = info->data->channels;
529 	indio_dev->num_channels = info->data->num_channels;
530 	ret = devm_iio_triggered_buffer_setup(&indio_dev->dev, indio_dev, NULL,
531 					      rockchip_saradc_trigger_handler,
532 					      NULL);
533 	if (ret)
534 		return ret;
535 
536 	info->nb.notifier_call = rockchip_saradc_volt_notify;
537 	ret = regulator_register_notifier(info->vref, &info->nb);
538 	if (ret)
539 		return ret;
540 
541 	ret = devm_add_action_or_reset(&pdev->dev,
542 				       rockchip_saradc_regulator_unreg_notifier,
543 				       info);
544 	if (ret)
545 		return ret;
546 
547 	mutex_init(&info->lock);
548 
549 	return devm_iio_device_register(&pdev->dev, indio_dev);
550 }
551 
552 static int rockchip_saradc_suspend(struct device *dev)
553 {
554 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
555 	struct rockchip_saradc *info = iio_priv(indio_dev);
556 
557 	clk_disable_unprepare(info->clk);
558 	clk_disable_unprepare(info->pclk);
559 	regulator_disable(info->vref);
560 
561 	return 0;
562 }
563 
564 static int rockchip_saradc_resume(struct device *dev)
565 {
566 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
567 	struct rockchip_saradc *info = iio_priv(indio_dev);
568 	int ret;
569 
570 	ret = regulator_enable(info->vref);
571 	if (ret)
572 		return ret;
573 
574 	ret = clk_prepare_enable(info->pclk);
575 	if (ret)
576 		return ret;
577 
578 	ret = clk_prepare_enable(info->clk);
579 	if (ret)
580 		clk_disable_unprepare(info->pclk);
581 
582 	return ret;
583 }
584 
585 static DEFINE_SIMPLE_DEV_PM_OPS(rockchip_saradc_pm_ops,
586 				rockchip_saradc_suspend,
587 				rockchip_saradc_resume);
588 
589 static struct platform_driver rockchip_saradc_driver = {
590 	.probe		= rockchip_saradc_probe,
591 	.driver		= {
592 		.name	= "rockchip-saradc",
593 		.of_match_table = rockchip_saradc_match,
594 		.pm	= pm_sleep_ptr(&rockchip_saradc_pm_ops),
595 	},
596 };
597 
598 module_platform_driver(rockchip_saradc_driver);
599 
600 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
601 MODULE_DESCRIPTION("Rockchip SARADC driver");
602 MODULE_LICENSE("GPL v2");
603