1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Freescale i.MX6UL touchscreen controller driver
4 //
5 // Copyright (C) 2015 Freescale Semiconductor, Inc.
6 
7 #include <linux/errno.h>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/input.h>
12 #include <linux/slab.h>
13 #include <linux/completion.h>
14 #include <linux/delay.h>
15 #include <linux/of.h>
16 #include <linux/interrupt.h>
17 #include <linux/platform_device.h>
18 #include <linux/clk.h>
19 #include <linux/io.h>
20 #include <linux/log2.h>
21 
22 /* ADC configuration registers field define */
23 #define ADC_AIEN		(0x1 << 7)
24 #define ADC_CONV_DISABLE	0x1F
25 #define ADC_AVGE		(0x1 << 5)
26 #define ADC_CAL			(0x1 << 7)
27 #define ADC_CALF		0x2
28 #define ADC_12BIT_MODE		(0x2 << 2)
29 #define ADC_CONV_MODE_MASK	(0x3 << 2)
30 #define ADC_IPG_CLK		0x00
31 #define ADC_INPUT_CLK_MASK	0x3
32 #define ADC_CLK_DIV_8		(0x03 << 5)
33 #define ADC_CLK_DIV_MASK	(0x3 << 5)
34 #define ADC_SHORT_SAMPLE_MODE	(0x0 << 4)
35 #define ADC_SAMPLE_MODE_MASK	(0x1 << 4)
36 #define ADC_HARDWARE_TRIGGER	(0x1 << 13)
37 #define ADC_AVGS_SHIFT		14
38 #define ADC_AVGS_MASK		(0x3 << 14)
39 #define SELECT_CHANNEL_4	0x04
40 #define SELECT_CHANNEL_1	0x01
41 #define DISABLE_CONVERSION_INT	(0x0 << 7)
42 
43 /* ADC registers */
44 #define REG_ADC_HC0		0x00
45 #define REG_ADC_HC1		0x04
46 #define REG_ADC_HC2		0x08
47 #define REG_ADC_HC3		0x0C
48 #define REG_ADC_HC4		0x10
49 #define REG_ADC_HS		0x14
50 #define REG_ADC_R0		0x18
51 #define REG_ADC_CFG		0x2C
52 #define REG_ADC_GC		0x30
53 #define REG_ADC_GS		0x34
54 
55 #define ADC_TIMEOUT		msecs_to_jiffies(100)
56 
57 /* TSC registers */
58 #define REG_TSC_BASIC_SETING	0x00
59 #define REG_TSC_PRE_CHARGE_TIME	0x10
60 #define REG_TSC_FLOW_CONTROL	0x20
61 #define REG_TSC_MEASURE_VALUE	0x30
62 #define REG_TSC_INT_EN		0x40
63 #define REG_TSC_INT_SIG_EN	0x50
64 #define REG_TSC_INT_STATUS	0x60
65 #define REG_TSC_DEBUG_MODE	0x70
66 #define REG_TSC_DEBUG_MODE2	0x80
67 
68 /* TSC configuration registers field define */
69 #define DETECT_4_WIRE_MODE	(0x0 << 4)
70 #define AUTO_MEASURE		0x1
71 #define MEASURE_SIGNAL		0x1
72 #define DETECT_SIGNAL		(0x1 << 4)
73 #define VALID_SIGNAL		(0x1 << 8)
74 #define MEASURE_INT_EN		0x1
75 #define MEASURE_SIG_EN		0x1
76 #define VALID_SIG_EN		(0x1 << 8)
77 #define DE_GLITCH_2		(0x2 << 29)
78 #define START_SENSE		(0x1 << 12)
79 #define TSC_DISABLE		(0x1 << 16)
80 #define DETECT_MODE		0x2
81 
82 struct imx6ul_tsc {
83 	struct device *dev;
84 	struct input_dev *input;
85 	void __iomem *tsc_regs;
86 	void __iomem *adc_regs;
87 	struct clk *tsc_clk;
88 	struct clk *adc_clk;
89 	struct gpio_desc *xnur_gpio;
90 
91 	u32 measure_delay_time;
92 	u32 pre_charge_time;
93 	bool average_enable;
94 	u32 average_select;
95 
96 	struct completion completion;
97 };
98 
99 /*
100  * TSC module need ADC to get the measure value. So
101  * before config TSC, we should initialize ADC module.
102  */
103 static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
104 {
105 	u32 adc_hc = 0;
106 	u32 adc_gc;
107 	u32 adc_gs;
108 	u32 adc_cfg;
109 	unsigned long timeout;
110 
111 	reinit_completion(&tsc->completion);
112 
113 	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
114 	adc_cfg &= ~(ADC_CONV_MODE_MASK | ADC_INPUT_CLK_MASK);
115 	adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;
116 	adc_cfg &= ~(ADC_CLK_DIV_MASK | ADC_SAMPLE_MODE_MASK);
117 	adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;
118 	if (tsc->average_enable) {
119 		adc_cfg &= ~ADC_AVGS_MASK;
120 		adc_cfg |= (tsc->average_select) << ADC_AVGS_SHIFT;
121 	}
122 	adc_cfg &= ~ADC_HARDWARE_TRIGGER;
123 	writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
124 
125 	/* enable calibration interrupt */
126 	adc_hc |= ADC_AIEN;
127 	adc_hc |= ADC_CONV_DISABLE;
128 	writel(adc_hc, tsc->adc_regs + REG_ADC_HC0);
129 
130 	/* start ADC calibration */
131 	adc_gc = readl(tsc->adc_regs + REG_ADC_GC);
132 	adc_gc |= ADC_CAL;
133 	if (tsc->average_enable)
134 		adc_gc |= ADC_AVGE;
135 	writel(adc_gc, tsc->adc_regs + REG_ADC_GC);
136 
137 	timeout = wait_for_completion_timeout
138 			(&tsc->completion, ADC_TIMEOUT);
139 	if (timeout == 0) {
140 		dev_err(tsc->dev, "Timeout for adc calibration\n");
141 		return -ETIMEDOUT;
142 	}
143 
144 	adc_gs = readl(tsc->adc_regs + REG_ADC_GS);
145 	if (adc_gs & ADC_CALF) {
146 		dev_err(tsc->dev, "ADC calibration failed\n");
147 		return -EINVAL;
148 	}
149 
150 	/* TSC need the ADC work in hardware trigger */
151 	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
152 	adc_cfg |= ADC_HARDWARE_TRIGGER;
153 	writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
154 
155 	return 0;
156 }
157 
158 /*
159  * This is a TSC workaround. Currently TSC misconnect two
160  * ADC channels, this function remap channel configure for
161  * hardware trigger.
162  */
163 static void imx6ul_tsc_channel_config(struct imx6ul_tsc *tsc)
164 {
165 	u32 adc_hc0, adc_hc1, adc_hc2, adc_hc3, adc_hc4;
166 
167 	adc_hc0 = DISABLE_CONVERSION_INT;
168 	writel(adc_hc0, tsc->adc_regs + REG_ADC_HC0);
169 
170 	adc_hc1 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_4;
171 	writel(adc_hc1, tsc->adc_regs + REG_ADC_HC1);
172 
173 	adc_hc2 = DISABLE_CONVERSION_INT;
174 	writel(adc_hc2, tsc->adc_regs + REG_ADC_HC2);
175 
176 	adc_hc3 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_1;
177 	writel(adc_hc3, tsc->adc_regs + REG_ADC_HC3);
178 
179 	adc_hc4 = DISABLE_CONVERSION_INT;
180 	writel(adc_hc4, tsc->adc_regs + REG_ADC_HC4);
181 }
182 
183 /*
184  * TSC setting, confige the pre-charge time and measure delay time.
185  * different touch screen may need different pre-charge time and
186  * measure delay time.
187  */
188 static void imx6ul_tsc_set(struct imx6ul_tsc *tsc)
189 {
190 	u32 basic_setting = 0;
191 	u32 start;
192 
193 	basic_setting |= tsc->measure_delay_time << 8;
194 	basic_setting |= DETECT_4_WIRE_MODE | AUTO_MEASURE;
195 	writel(basic_setting, tsc->tsc_regs + REG_TSC_BASIC_SETING);
196 
197 	writel(DE_GLITCH_2, tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
198 
199 	writel(tsc->pre_charge_time, tsc->tsc_regs + REG_TSC_PRE_CHARGE_TIME);
200 	writel(MEASURE_INT_EN, tsc->tsc_regs + REG_TSC_INT_EN);
201 	writel(MEASURE_SIG_EN | VALID_SIG_EN,
202 		tsc->tsc_regs + REG_TSC_INT_SIG_EN);
203 
204 	/* start sense detection */
205 	start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
206 	start |= START_SENSE;
207 	start &= ~TSC_DISABLE;
208 	writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
209 }
210 
211 static int imx6ul_tsc_init(struct imx6ul_tsc *tsc)
212 {
213 	int err;
214 
215 	err = imx6ul_adc_init(tsc);
216 	if (err)
217 		return err;
218 	imx6ul_tsc_channel_config(tsc);
219 	imx6ul_tsc_set(tsc);
220 
221 	return 0;
222 }
223 
224 static void imx6ul_tsc_disable(struct imx6ul_tsc *tsc)
225 {
226 	u32 tsc_flow;
227 	u32 adc_cfg;
228 
229 	/* TSC controller enters to idle status */
230 	tsc_flow = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
231 	tsc_flow |= TSC_DISABLE;
232 	writel(tsc_flow, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
233 
234 	/* ADC controller enters to stop mode */
235 	adc_cfg = readl(tsc->adc_regs + REG_ADC_HC0);
236 	adc_cfg |= ADC_CONV_DISABLE;
237 	writel(adc_cfg, tsc->adc_regs + REG_ADC_HC0);
238 }
239 
240 /* Delay some time (max 2ms), wait the pre-charge done. */
241 static bool tsc_wait_detect_mode(struct imx6ul_tsc *tsc)
242 {
243 	unsigned long timeout = jiffies + msecs_to_jiffies(2);
244 	u32 state_machine;
245 	u32 debug_mode2;
246 
247 	do {
248 		if (time_after(jiffies, timeout))
249 			return false;
250 
251 		usleep_range(200, 400);
252 		debug_mode2 = readl(tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
253 		state_machine = (debug_mode2 >> 20) & 0x7;
254 	} while (state_machine != DETECT_MODE);
255 
256 	usleep_range(200, 400);
257 	return true;
258 }
259 
260 static irqreturn_t tsc_irq_fn(int irq, void *dev_id)
261 {
262 	struct imx6ul_tsc *tsc = dev_id;
263 	u32 status;
264 	u32 value;
265 	u32 x, y;
266 	u32 start;
267 
268 	status = readl(tsc->tsc_regs + REG_TSC_INT_STATUS);
269 
270 	/* write 1 to clear the bit measure-signal */
271 	writel(MEASURE_SIGNAL | DETECT_SIGNAL,
272 		tsc->tsc_regs + REG_TSC_INT_STATUS);
273 
274 	/* It's a HW self-clean bit. Set this bit and start sense detection */
275 	start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
276 	start |= START_SENSE;
277 	writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
278 
279 	if (status & MEASURE_SIGNAL) {
280 		value = readl(tsc->tsc_regs + REG_TSC_MEASURE_VALUE);
281 		x = (value >> 16) & 0x0fff;
282 		y = value & 0x0fff;
283 
284 		/*
285 		 * In detect mode, we can get the xnur gpio value,
286 		 * otherwise assume contact is stiull active.
287 		 */
288 		if (!tsc_wait_detect_mode(tsc) ||
289 		    gpiod_get_value_cansleep(tsc->xnur_gpio)) {
290 			input_report_key(tsc->input, BTN_TOUCH, 1);
291 			input_report_abs(tsc->input, ABS_X, x);
292 			input_report_abs(tsc->input, ABS_Y, y);
293 		} else {
294 			input_report_key(tsc->input, BTN_TOUCH, 0);
295 		}
296 
297 		input_sync(tsc->input);
298 	}
299 
300 	return IRQ_HANDLED;
301 }
302 
303 static irqreturn_t adc_irq_fn(int irq, void *dev_id)
304 {
305 	struct imx6ul_tsc *tsc = dev_id;
306 	u32 coco;
307 
308 	coco = readl(tsc->adc_regs + REG_ADC_HS);
309 	if (coco & 0x01) {
310 		readl(tsc->adc_regs + REG_ADC_R0);
311 		complete(&tsc->completion);
312 	}
313 
314 	return IRQ_HANDLED;
315 }
316 
317 static int imx6ul_tsc_start(struct imx6ul_tsc *tsc)
318 {
319 	int err;
320 
321 	err = clk_prepare_enable(tsc->adc_clk);
322 	if (err) {
323 		dev_err(tsc->dev,
324 			"Could not prepare or enable the adc clock: %d\n",
325 			err);
326 		return err;
327 	}
328 
329 	err = clk_prepare_enable(tsc->tsc_clk);
330 	if (err) {
331 		dev_err(tsc->dev,
332 			"Could not prepare or enable the tsc clock: %d\n",
333 			err);
334 		goto disable_adc_clk;
335 	}
336 
337 	err = imx6ul_tsc_init(tsc);
338 	if (err)
339 		goto disable_tsc_clk;
340 
341 	return 0;
342 
343 disable_tsc_clk:
344 	clk_disable_unprepare(tsc->tsc_clk);
345 disable_adc_clk:
346 	clk_disable_unprepare(tsc->adc_clk);
347 	return err;
348 }
349 
350 static void imx6ul_tsc_stop(struct imx6ul_tsc *tsc)
351 {
352 	imx6ul_tsc_disable(tsc);
353 
354 	clk_disable_unprepare(tsc->tsc_clk);
355 	clk_disable_unprepare(tsc->adc_clk);
356 }
357 
358 
359 static int imx6ul_tsc_open(struct input_dev *input_dev)
360 {
361 	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
362 
363 	return imx6ul_tsc_start(tsc);
364 }
365 
366 static void imx6ul_tsc_close(struct input_dev *input_dev)
367 {
368 	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
369 
370 	imx6ul_tsc_stop(tsc);
371 }
372 
373 static int imx6ul_tsc_probe(struct platform_device *pdev)
374 {
375 	struct device_node *np = pdev->dev.of_node;
376 	struct imx6ul_tsc *tsc;
377 	struct input_dev *input_dev;
378 	int err;
379 	int tsc_irq;
380 	int adc_irq;
381 	u32 average_samples;
382 
383 	tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
384 	if (!tsc)
385 		return -ENOMEM;
386 
387 	input_dev = devm_input_allocate_device(&pdev->dev);
388 	if (!input_dev)
389 		return -ENOMEM;
390 
391 	input_dev->name = "iMX6UL Touchscreen Controller";
392 	input_dev->id.bustype = BUS_HOST;
393 
394 	input_dev->open = imx6ul_tsc_open;
395 	input_dev->close = imx6ul_tsc_close;
396 
397 	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
398 	input_set_abs_params(input_dev, ABS_X, 0, 0xFFF, 0, 0);
399 	input_set_abs_params(input_dev, ABS_Y, 0, 0xFFF, 0, 0);
400 
401 	input_set_drvdata(input_dev, tsc);
402 
403 	tsc->dev = &pdev->dev;
404 	tsc->input = input_dev;
405 	init_completion(&tsc->completion);
406 
407 	tsc->xnur_gpio = devm_gpiod_get(&pdev->dev, "xnur", GPIOD_IN);
408 	if (IS_ERR(tsc->xnur_gpio)) {
409 		err = PTR_ERR(tsc->xnur_gpio);
410 		dev_err(&pdev->dev,
411 			"failed to request GPIO tsc_X- (xnur): %d\n", err);
412 		return err;
413 	}
414 
415 	tsc->tsc_regs = devm_platform_ioremap_resource(pdev, 0);
416 	if (IS_ERR(tsc->tsc_regs)) {
417 		err = PTR_ERR(tsc->tsc_regs);
418 		dev_err(&pdev->dev, "failed to remap tsc memory: %d\n", err);
419 		return err;
420 	}
421 
422 	tsc->adc_regs = devm_platform_ioremap_resource(pdev, 1);
423 	if (IS_ERR(tsc->adc_regs)) {
424 		err = PTR_ERR(tsc->adc_regs);
425 		dev_err(&pdev->dev, "failed to remap adc memory: %d\n", err);
426 		return err;
427 	}
428 
429 	tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");
430 	if (IS_ERR(tsc->tsc_clk)) {
431 		err = PTR_ERR(tsc->tsc_clk);
432 		dev_err(&pdev->dev, "failed getting tsc clock: %d\n", err);
433 		return err;
434 	}
435 
436 	tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");
437 	if (IS_ERR(tsc->adc_clk)) {
438 		err = PTR_ERR(tsc->adc_clk);
439 		dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);
440 		return err;
441 	}
442 
443 	tsc_irq = platform_get_irq(pdev, 0);
444 	if (tsc_irq < 0)
445 		return tsc_irq;
446 
447 	adc_irq = platform_get_irq(pdev, 1);
448 	if (adc_irq < 0)
449 		return adc_irq;
450 
451 	err = devm_request_threaded_irq(tsc->dev, tsc_irq,
452 					NULL, tsc_irq_fn, IRQF_ONESHOT,
453 					dev_name(&pdev->dev), tsc);
454 	if (err) {
455 		dev_err(&pdev->dev,
456 			"failed requesting tsc irq %d: %d\n",
457 			tsc_irq, err);
458 		return err;
459 	}
460 
461 	err = devm_request_irq(tsc->dev, adc_irq, adc_irq_fn, 0,
462 				dev_name(&pdev->dev), tsc);
463 	if (err) {
464 		dev_err(&pdev->dev,
465 			"failed requesting adc irq %d: %d\n",
466 			adc_irq, err);
467 		return err;
468 	}
469 
470 	err = of_property_read_u32(np, "measure-delay-time",
471 				   &tsc->measure_delay_time);
472 	if (err)
473 		tsc->measure_delay_time = 0xffff;
474 
475 	err = of_property_read_u32(np, "pre-charge-time",
476 				   &tsc->pre_charge_time);
477 	if (err)
478 		tsc->pre_charge_time = 0xfff;
479 
480 	err = of_property_read_u32(np, "touchscreen-average-samples",
481 				   &average_samples);
482 	if (err)
483 		average_samples = 1;
484 
485 	switch (average_samples) {
486 	case 1:
487 		tsc->average_enable = false;
488 		tsc->average_select = 0; /* value unused; initialize anyway */
489 		break;
490 	case 4:
491 	case 8:
492 	case 16:
493 	case 32:
494 		tsc->average_enable = true;
495 		tsc->average_select = ilog2(average_samples) - 2;
496 		break;
497 	default:
498 		dev_err(&pdev->dev,
499 			"touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
500 			average_samples);
501 		return -EINVAL;
502 	}
503 
504 	err = input_register_device(tsc->input);
505 	if (err) {
506 		dev_err(&pdev->dev,
507 			"failed to register input device: %d\n", err);
508 		return err;
509 	}
510 
511 	platform_set_drvdata(pdev, tsc);
512 	return 0;
513 }
514 
515 static int __maybe_unused imx6ul_tsc_suspend(struct device *dev)
516 {
517 	struct platform_device *pdev = to_platform_device(dev);
518 	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
519 	struct input_dev *input_dev = tsc->input;
520 
521 	mutex_lock(&input_dev->mutex);
522 
523 	if (input_device_enabled(input_dev))
524 		imx6ul_tsc_stop(tsc);
525 
526 	mutex_unlock(&input_dev->mutex);
527 
528 	return 0;
529 }
530 
531 static int __maybe_unused imx6ul_tsc_resume(struct device *dev)
532 {
533 	struct platform_device *pdev = to_platform_device(dev);
534 	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
535 	struct input_dev *input_dev = tsc->input;
536 	int retval = 0;
537 
538 	mutex_lock(&input_dev->mutex);
539 
540 	if (input_device_enabled(input_dev))
541 		retval = imx6ul_tsc_start(tsc);
542 
543 	mutex_unlock(&input_dev->mutex);
544 
545 	return retval;
546 }
547 
548 static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
549 			 imx6ul_tsc_suspend, imx6ul_tsc_resume);
550 
551 static const struct of_device_id imx6ul_tsc_match[] = {
552 	{ .compatible = "fsl,imx6ul-tsc", },
553 	{ /* sentinel */ }
554 };
555 MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
556 
557 static struct platform_driver imx6ul_tsc_driver = {
558 	.driver		= {
559 		.name	= "imx6ul-tsc",
560 		.of_match_table	= imx6ul_tsc_match,
561 		.pm	= &imx6ul_tsc_pm_ops,
562 	},
563 	.probe		= imx6ul_tsc_probe,
564 };
565 module_platform_driver(imx6ul_tsc_driver);
566 
567 MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");
568 MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");
569 MODULE_LICENSE("GPL v2");
570