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 */
imx6ul_adc_init(struct imx6ul_tsc * tsc)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 */
imx6ul_tsc_channel_config(struct imx6ul_tsc * tsc)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 */
imx6ul_tsc_set(struct imx6ul_tsc * tsc)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
imx6ul_tsc_init(struct imx6ul_tsc * tsc)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
imx6ul_tsc_disable(struct imx6ul_tsc * tsc)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. */
tsc_wait_detect_mode(struct imx6ul_tsc * tsc)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
tsc_irq_fn(int irq,void * dev_id)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
adc_irq_fn(int irq,void * dev_id)303 static irqreturn_t adc_irq_fn(int irq, void *dev_id)
304 {
305 struct imx6ul_tsc *tsc = dev_id;
306 u32 coco;
307 u32 value;
308
309 coco = readl(tsc->adc_regs + REG_ADC_HS);
310 if (coco & 0x01) {
311 value = readl(tsc->adc_regs + REG_ADC_R0);
312 complete(&tsc->completion);
313 }
314
315 return IRQ_HANDLED;
316 }
317
imx6ul_tsc_open(struct input_dev * input_dev)318 static int imx6ul_tsc_open(struct input_dev *input_dev)
319 {
320 struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
321 int err;
322
323 err = clk_prepare_enable(tsc->adc_clk);
324 if (err) {
325 dev_err(tsc->dev,
326 "Could not prepare or enable the adc clock: %d\n",
327 err);
328 return err;
329 }
330
331 err = clk_prepare_enable(tsc->tsc_clk);
332 if (err) {
333 dev_err(tsc->dev,
334 "Could not prepare or enable the tsc clock: %d\n",
335 err);
336 goto disable_adc_clk;
337 }
338
339 err = imx6ul_tsc_init(tsc);
340 if (err)
341 goto disable_tsc_clk;
342
343 return 0;
344
345 disable_tsc_clk:
346 clk_disable_unprepare(tsc->tsc_clk);
347 disable_adc_clk:
348 clk_disable_unprepare(tsc->adc_clk);
349 return err;
350 }
351
imx6ul_tsc_close(struct input_dev * input_dev)352 static void imx6ul_tsc_close(struct input_dev *input_dev)
353 {
354 struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
355
356 imx6ul_tsc_disable(tsc);
357
358 clk_disable_unprepare(tsc->tsc_clk);
359 clk_disable_unprepare(tsc->adc_clk);
360 }
361
imx6ul_tsc_probe(struct platform_device * pdev)362 static int imx6ul_tsc_probe(struct platform_device *pdev)
363 {
364 struct device_node *np = pdev->dev.of_node;
365 struct imx6ul_tsc *tsc;
366 struct input_dev *input_dev;
367 int err;
368 int tsc_irq;
369 int adc_irq;
370 u32 average_samples;
371
372 tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
373 if (!tsc)
374 return -ENOMEM;
375
376 input_dev = devm_input_allocate_device(&pdev->dev);
377 if (!input_dev)
378 return -ENOMEM;
379
380 input_dev->name = "iMX6UL Touchscreen Controller";
381 input_dev->id.bustype = BUS_HOST;
382
383 input_dev->open = imx6ul_tsc_open;
384 input_dev->close = imx6ul_tsc_close;
385
386 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
387 input_set_abs_params(input_dev, ABS_X, 0, 0xFFF, 0, 0);
388 input_set_abs_params(input_dev, ABS_Y, 0, 0xFFF, 0, 0);
389
390 input_set_drvdata(input_dev, tsc);
391
392 tsc->dev = &pdev->dev;
393 tsc->input = input_dev;
394 init_completion(&tsc->completion);
395
396 tsc->xnur_gpio = devm_gpiod_get(&pdev->dev, "xnur", GPIOD_IN);
397 if (IS_ERR(tsc->xnur_gpio)) {
398 err = PTR_ERR(tsc->xnur_gpio);
399 dev_err(&pdev->dev,
400 "failed to request GPIO tsc_X- (xnur): %d\n", err);
401 return err;
402 }
403
404 tsc->tsc_regs = devm_platform_ioremap_resource(pdev, 0);
405 if (IS_ERR(tsc->tsc_regs)) {
406 err = PTR_ERR(tsc->tsc_regs);
407 dev_err(&pdev->dev, "failed to remap tsc memory: %d\n", err);
408 return err;
409 }
410
411 tsc->adc_regs = devm_platform_ioremap_resource(pdev, 1);
412 if (IS_ERR(tsc->adc_regs)) {
413 err = PTR_ERR(tsc->adc_regs);
414 dev_err(&pdev->dev, "failed to remap adc memory: %d\n", err);
415 return err;
416 }
417
418 tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");
419 if (IS_ERR(tsc->tsc_clk)) {
420 err = PTR_ERR(tsc->tsc_clk);
421 dev_err(&pdev->dev, "failed getting tsc clock: %d\n", err);
422 return err;
423 }
424
425 tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");
426 if (IS_ERR(tsc->adc_clk)) {
427 err = PTR_ERR(tsc->adc_clk);
428 dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);
429 return err;
430 }
431
432 tsc_irq = platform_get_irq(pdev, 0);
433 if (tsc_irq < 0)
434 return tsc_irq;
435
436 adc_irq = platform_get_irq(pdev, 1);
437 if (adc_irq < 0)
438 return adc_irq;
439
440 err = devm_request_threaded_irq(tsc->dev, tsc_irq,
441 NULL, tsc_irq_fn, IRQF_ONESHOT,
442 dev_name(&pdev->dev), tsc);
443 if (err) {
444 dev_err(&pdev->dev,
445 "failed requesting tsc irq %d: %d\n",
446 tsc_irq, err);
447 return err;
448 }
449
450 err = devm_request_irq(tsc->dev, adc_irq, adc_irq_fn, 0,
451 dev_name(&pdev->dev), tsc);
452 if (err) {
453 dev_err(&pdev->dev,
454 "failed requesting adc irq %d: %d\n",
455 adc_irq, err);
456 return err;
457 }
458
459 err = of_property_read_u32(np, "measure-delay-time",
460 &tsc->measure_delay_time);
461 if (err)
462 tsc->measure_delay_time = 0xffff;
463
464 err = of_property_read_u32(np, "pre-charge-time",
465 &tsc->pre_charge_time);
466 if (err)
467 tsc->pre_charge_time = 0xfff;
468
469 err = of_property_read_u32(np, "touchscreen-average-samples",
470 &average_samples);
471 if (err)
472 average_samples = 1;
473
474 switch (average_samples) {
475 case 1:
476 tsc->average_enable = false;
477 tsc->average_select = 0; /* value unused; initialize anyway */
478 break;
479 case 4:
480 case 8:
481 case 16:
482 case 32:
483 tsc->average_enable = true;
484 tsc->average_select = ilog2(average_samples) - 2;
485 break;
486 default:
487 dev_err(&pdev->dev,
488 "touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
489 average_samples);
490 return -EINVAL;
491 }
492
493 err = input_register_device(tsc->input);
494 if (err) {
495 dev_err(&pdev->dev,
496 "failed to register input device: %d\n", err);
497 return err;
498 }
499
500 platform_set_drvdata(pdev, tsc);
501 return 0;
502 }
503
imx6ul_tsc_suspend(struct device * dev)504 static int __maybe_unused imx6ul_tsc_suspend(struct device *dev)
505 {
506 struct platform_device *pdev = to_platform_device(dev);
507 struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
508 struct input_dev *input_dev = tsc->input;
509
510 mutex_lock(&input_dev->mutex);
511
512 if (input_dev->users) {
513 imx6ul_tsc_disable(tsc);
514
515 clk_disable_unprepare(tsc->tsc_clk);
516 clk_disable_unprepare(tsc->adc_clk);
517 }
518
519 mutex_unlock(&input_dev->mutex);
520
521 return 0;
522 }
523
imx6ul_tsc_resume(struct device * dev)524 static int __maybe_unused imx6ul_tsc_resume(struct device *dev)
525 {
526 struct platform_device *pdev = to_platform_device(dev);
527 struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
528 struct input_dev *input_dev = tsc->input;
529 int retval = 0;
530
531 mutex_lock(&input_dev->mutex);
532
533 if (input_dev->users) {
534 retval = clk_prepare_enable(tsc->adc_clk);
535 if (retval)
536 goto out;
537
538 retval = clk_prepare_enable(tsc->tsc_clk);
539 if (retval) {
540 clk_disable_unprepare(tsc->adc_clk);
541 goto out;
542 }
543
544 retval = imx6ul_tsc_init(tsc);
545 }
546
547 out:
548 mutex_unlock(&input_dev->mutex);
549 return retval;
550 }
551
552 static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
553 imx6ul_tsc_suspend, imx6ul_tsc_resume);
554
555 static const struct of_device_id imx6ul_tsc_match[] = {
556 { .compatible = "fsl,imx6ul-tsc", },
557 { /* sentinel */ }
558 };
559 MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
560
561 static struct platform_driver imx6ul_tsc_driver = {
562 .driver = {
563 .name = "imx6ul-tsc",
564 .of_match_table = imx6ul_tsc_match,
565 .pm = &imx6ul_tsc_pm_ops,
566 },
567 .probe = imx6ul_tsc_probe,
568 };
569 module_platform_driver(imx6ul_tsc_driver);
570
571 MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");
572 MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");
573 MODULE_LICENSE("GPL v2");
574
