1/*
  2 * Freescale i.MX6UL touchscreen controller driver
  3 *
  4 * Copyright (C) 2015 Freescale Semiconductor, Inc.
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License version 2 as
  8 * published by the Free Software Foundation.
  9 */
 10
 11#include <linux/errno.h>
 12#include <linux/kernel.h>
 13#include <linux/module.h>
 14#include <linux/gpio/consumer.h>
 15#include <linux/input.h>
 16#include <linux/slab.h>
 17#include <linux/completion.h>
 18#include <linux/delay.h>
 19#include <linux/of.h>
 20#include <linux/interrupt.h>
 21#include <linux/platform_device.h>
 22#include <linux/clk.h>
 23#include <linux/io.h>
 24#include <linux/log2.h>
 25
 26/* ADC configuration registers field define */
 27#define ADC_AIEN		(0x1 << 7)
 28#define ADC_CONV_DISABLE	0x1F
 29#define ADC_AVGE		(0x1 << 5)
 30#define ADC_CAL			(0x1 << 7)
 31#define ADC_CALF		0x2
 32#define ADC_12BIT_MODE		(0x2 << 2)
 33#define ADC_CONV_MODE_MASK	(0x3 << 2)
 34#define ADC_IPG_CLK		0x00
 35#define ADC_INPUT_CLK_MASK	0x3
 36#define ADC_CLK_DIV_8		(0x03 << 5)
 37#define ADC_CLK_DIV_MASK	(0x3 << 5)
 38#define ADC_SHORT_SAMPLE_MODE	(0x0 << 4)
 39#define ADC_SAMPLE_MODE_MASK	(0x1 << 4)
 40#define ADC_HARDWARE_TRIGGER	(0x1 << 13)
 41#define ADC_AVGS_SHIFT		14
 42#define ADC_AVGS_MASK		(0x3 << 14)
 43#define SELECT_CHANNEL_4	0x04
 44#define SELECT_CHANNEL_1	0x01
 45#define DISABLE_CONVERSION_INT	(0x0 << 7)
 46
 47/* ADC registers */
 48#define REG_ADC_HC0		0x00
 49#define REG_ADC_HC1		0x04
 50#define REG_ADC_HC2		0x08
 51#define REG_ADC_HC3		0x0C
 52#define REG_ADC_HC4		0x10
 53#define REG_ADC_HS		0x14
 54#define REG_ADC_R0		0x18
 55#define REG_ADC_CFG		0x2C
 56#define REG_ADC_GC		0x30
 57#define REG_ADC_GS		0x34
 58
 59#define ADC_TIMEOUT		msecs_to_jiffies(100)
 60
 61/* TSC registers */
 62#define REG_TSC_BASIC_SETING	0x00
 63#define REG_TSC_PRE_CHARGE_TIME	0x10
 64#define REG_TSC_FLOW_CONTROL	0x20
 65#define REG_TSC_MEASURE_VALUE	0x30
 66#define REG_TSC_INT_EN		0x40
 67#define REG_TSC_INT_SIG_EN	0x50
 68#define REG_TSC_INT_STATUS	0x60
 69#define REG_TSC_DEBUG_MODE	0x70
 70#define REG_TSC_DEBUG_MODE2	0x80
 71
 72/* TSC configuration registers field define */
 73#define DETECT_4_WIRE_MODE	(0x0 << 4)
 74#define AUTO_MEASURE		0x1
 75#define MEASURE_SIGNAL		0x1
 76#define DETECT_SIGNAL		(0x1 << 4)
 77#define VALID_SIGNAL		(0x1 << 8)
 78#define MEASURE_INT_EN		0x1
 79#define MEASURE_SIG_EN		0x1
 80#define VALID_SIG_EN		(0x1 << 8)
 81#define DE_GLITCH_2		(0x2 << 29)
 82#define START_SENSE		(0x1 << 12)
 83#define TSC_DISABLE		(0x1 << 16)
 84#define DETECT_MODE		0x2
 85
 86struct imx6ul_tsc {
 87	struct device *dev;
 88	struct input_dev *input;
 89	void __iomem *tsc_regs;
 90	void __iomem *adc_regs;
 91	struct clk *tsc_clk;
 92	struct clk *adc_clk;
 93	struct gpio_desc *xnur_gpio;
 94
 95	u32 measure_delay_time;
 96	u32 pre_charge_time;
 97	bool average_enable;
 98	u32 average_select;
 99
100	struct completion completion;
101};
102
103/*
104 * TSC module need ADC to get the measure value. So
105 * before config TSC, we should initialize ADC module.
106 */
107static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
108{
109	u32 adc_hc = 0;
110	u32 adc_gc;
111	u32 adc_gs;
112	u32 adc_cfg;
113	unsigned long timeout;
114
115	reinit_completion(&tsc->completion);
116
117	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
118	adc_cfg &= ~(ADC_CONV_MODE_MASK | ADC_INPUT_CLK_MASK);
119	adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;
120	adc_cfg &= ~(ADC_CLK_DIV_MASK | ADC_SAMPLE_MODE_MASK);
121	adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;
122	if (tsc->average_enable) {
123		adc_cfg &= ~ADC_AVGS_MASK;
124		adc_cfg |= (tsc->average_select) << ADC_AVGS_SHIFT;
125	}
126	adc_cfg &= ~ADC_HARDWARE_TRIGGER;
127	writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
128
129	/* enable calibration interrupt */
130	adc_hc |= ADC_AIEN;
131	adc_hc |= ADC_CONV_DISABLE;
132	writel(adc_hc, tsc->adc_regs + REG_ADC_HC0);
133
134	/* start ADC calibration */
135	adc_gc = readl(tsc->adc_regs + REG_ADC_GC);
136	adc_gc |= ADC_CAL;
137	if (tsc->average_enable)
138		adc_gc |= ADC_AVGE;
139	writel(adc_gc, tsc->adc_regs + REG_ADC_GC);
140
141	timeout = wait_for_completion_timeout
142			(&tsc->completion, ADC_TIMEOUT);
143	if (timeout == 0) {
144		dev_err(tsc->dev, "Timeout for adc calibration\n");
145		return -ETIMEDOUT;
146	}
147
148	adc_gs = readl(tsc->adc_regs + REG_ADC_GS);
149	if (adc_gs & ADC_CALF) {
150		dev_err(tsc->dev, "ADC calibration failed\n");
151		return -EINVAL;
152	}
153
154	/* TSC need the ADC work in hardware trigger */
155	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
156	adc_cfg |= ADC_HARDWARE_TRIGGER;
157	writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
158
159	return 0;
160}
161
162/*
163 * This is a TSC workaround. Currently TSC misconnect two
164 * ADC channels, this function remap channel configure for
165 * hardware trigger.
166 */
167static void imx6ul_tsc_channel_config(struct imx6ul_tsc *tsc)
168{
169	u32 adc_hc0, adc_hc1, adc_hc2, adc_hc3, adc_hc4;
170
171	adc_hc0 = DISABLE_CONVERSION_INT;
172	writel(adc_hc0, tsc->adc_regs + REG_ADC_HC0);
173
174	adc_hc1 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_4;
175	writel(adc_hc1, tsc->adc_regs + REG_ADC_HC1);
176
177	adc_hc2 = DISABLE_CONVERSION_INT;
178	writel(adc_hc2, tsc->adc_regs + REG_ADC_HC2);
179
180	adc_hc3 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_1;
181	writel(adc_hc3, tsc->adc_regs + REG_ADC_HC3);
182
183	adc_hc4 = DISABLE_CONVERSION_INT;
184	writel(adc_hc4, tsc->adc_regs + REG_ADC_HC4);
185}
186
187/*
188 * TSC setting, confige the pre-charge time and measure delay time.
189 * different touch screen may need different pre-charge time and
190 * measure delay time.
191 */
192static void imx6ul_tsc_set(struct imx6ul_tsc *tsc)
193{
194	u32 basic_setting = 0;
195	u32 start;
196
197	basic_setting |= tsc->measure_delay_time << 8;
198	basic_setting |= DETECT_4_WIRE_MODE | AUTO_MEASURE;
199	writel(basic_setting, tsc->tsc_regs + REG_TSC_BASIC_SETING);
200
201	writel(DE_GLITCH_2, tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
202
203	writel(tsc->pre_charge_time, tsc->tsc_regs + REG_TSC_PRE_CHARGE_TIME);
204	writel(MEASURE_INT_EN, tsc->tsc_regs + REG_TSC_INT_EN);
205	writel(MEASURE_SIG_EN | VALID_SIG_EN,
206		tsc->tsc_regs + REG_TSC_INT_SIG_EN);
207
208	/* start sense detection */
209	start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
210	start |= START_SENSE;
211	start &= ~TSC_DISABLE;
212	writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
213}
214
215static int imx6ul_tsc_init(struct imx6ul_tsc *tsc)
216{
217	int err;
218
219	err = imx6ul_adc_init(tsc);
220	if (err)
221		return err;
222	imx6ul_tsc_channel_config(tsc);
223	imx6ul_tsc_set(tsc);
224
225	return 0;
226}
227
228static void imx6ul_tsc_disable(struct imx6ul_tsc *tsc)
229{
230	u32 tsc_flow;
231	u32 adc_cfg;
232
233	/* TSC controller enters to idle status */
234	tsc_flow = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
235	tsc_flow |= TSC_DISABLE;
236	writel(tsc_flow, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
237
238	/* ADC controller enters to stop mode */
239	adc_cfg = readl(tsc->adc_regs + REG_ADC_HC0);
240	adc_cfg |= ADC_CONV_DISABLE;
241	writel(adc_cfg, tsc->adc_regs + REG_ADC_HC0);
242}
243
244/* Delay some time (max 2ms), wait the pre-charge done. */
245static bool tsc_wait_detect_mode(struct imx6ul_tsc *tsc)
246{
247	unsigned long timeout = jiffies + msecs_to_jiffies(2);
248	u32 state_machine;
249	u32 debug_mode2;
250
251	do {
252		if (time_after(jiffies, timeout))
253			return false;
254
255		usleep_range(200, 400);
256		debug_mode2 = readl(tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
257		state_machine = (debug_mode2 >> 20) & 0x7;
258	} while (state_machine != DETECT_MODE);
259
260	usleep_range(200, 400);
261	return true;
262}
263
264static irqreturn_t tsc_irq_fn(int irq, void *dev_id)
265{
266	struct imx6ul_tsc *tsc = dev_id;
267	u32 status;
268	u32 value;
269	u32 x, y;
270	u32 start;
271
272	status = readl(tsc->tsc_regs + REG_TSC_INT_STATUS);
273
274	/* write 1 to clear the bit measure-signal */
275	writel(MEASURE_SIGNAL | DETECT_SIGNAL,
276		tsc->tsc_regs + REG_TSC_INT_STATUS);
277
278	/* It's a HW self-clean bit. Set this bit and start sense detection */
279	start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
280	start |= START_SENSE;
281	writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
282
283	if (status & MEASURE_SIGNAL) {
284		value = readl(tsc->tsc_regs + REG_TSC_MEASURE_VALUE);
285		x = (value >> 16) & 0x0fff;
286		y = value & 0x0fff;
287
288		/*
289		 * In detect mode, we can get the xnur gpio value,
290		 * otherwise assume contact is stiull active.
291		 */
292		if (!tsc_wait_detect_mode(tsc) ||
293		    gpiod_get_value_cansleep(tsc->xnur_gpio)) {
294			input_report_key(tsc->input, BTN_TOUCH, 1);
295			input_report_abs(tsc->input, ABS_X, x);
296			input_report_abs(tsc->input, ABS_Y, y);
297		} else {
298			input_report_key(tsc->input, BTN_TOUCH, 0);
299		}
300
301		input_sync(tsc->input);
302	}
303
304	return IRQ_HANDLED;
305}
306
307static irqreturn_t adc_irq_fn(int irq, void *dev_id)
308{
309	struct imx6ul_tsc *tsc = dev_id;
310	u32 coco;
311	u32 value;
312
313	coco = readl(tsc->adc_regs + REG_ADC_HS);
314	if (coco & 0x01) {
315		value = readl(tsc->adc_regs + REG_ADC_R0);
316		complete(&tsc->completion);
317	}
318
319	return IRQ_HANDLED;
320}
321
322static int imx6ul_tsc_open(struct input_dev *input_dev)
323{
324	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
325	int err;
326
327	err = clk_prepare_enable(tsc->adc_clk);
328	if (err) {
329		dev_err(tsc->dev,
330			"Could not prepare or enable the adc clock: %d\n",
331			err);
332		return err;
333	}
334
335	err = clk_prepare_enable(tsc->tsc_clk);
336	if (err) {
337		dev_err(tsc->dev,
338			"Could not prepare or enable the tsc clock: %d\n",
339			err);
340		clk_disable_unprepare(tsc->adc_clk);
341		return err;
342	}
343
344	return imx6ul_tsc_init(tsc);
345}
346
347static void imx6ul_tsc_close(struct input_dev *input_dev)
348{
349	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
350
351	imx6ul_tsc_disable(tsc);
352
353	clk_disable_unprepare(tsc->tsc_clk);
354	clk_disable_unprepare(tsc->adc_clk);
355}
356
357static int imx6ul_tsc_probe(struct platform_device *pdev)
358{
359	struct device_node *np = pdev->dev.of_node;
360	struct imx6ul_tsc *tsc;
361	struct input_dev *input_dev;
362	struct resource *tsc_mem;
363	struct resource *adc_mem;
364	int err;
365	int tsc_irq;
366	int adc_irq;
367	u32 average_samples;
368
369	tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
370	if (!tsc)
371		return -ENOMEM;
372
373	input_dev = devm_input_allocate_device(&pdev->dev);
374	if (!input_dev)
375		return -ENOMEM;
376
377	input_dev->name = "iMX6UL Touchscreen Controller";
378	input_dev->id.bustype = BUS_HOST;
379
380	input_dev->open = imx6ul_tsc_open;
381	input_dev->close = imx6ul_tsc_close;
382
383	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
384	input_set_abs_params(input_dev, ABS_X, 0, 0xFFF, 0, 0);
385	input_set_abs_params(input_dev, ABS_Y, 0, 0xFFF, 0, 0);
386
387	input_set_drvdata(input_dev, tsc);
388
389	tsc->dev = &pdev->dev;
390	tsc->input = input_dev;
391	init_completion(&tsc->completion);
392
393	tsc->xnur_gpio = devm_gpiod_get(&pdev->dev, "xnur", GPIOD_IN);
394	if (IS_ERR(tsc->xnur_gpio)) {
395		err = PTR_ERR(tsc->xnur_gpio);
396		dev_err(&pdev->dev,
397			"failed to request GPIO tsc_X- (xnur): %d\n", err);
398		return err;
399	}
400
401	tsc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
402	tsc->tsc_regs = devm_ioremap_resource(&pdev->dev, tsc_mem);
403	if (IS_ERR(tsc->tsc_regs)) {
404		err = PTR_ERR(tsc->tsc_regs);
405		dev_err(&pdev->dev, "failed to remap tsc memory: %d\n", err);
406		return err;
407	}
408
409	adc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
410	tsc->adc_regs = devm_ioremap_resource(&pdev->dev, adc_mem);
411	if (IS_ERR(tsc->adc_regs)) {
412		err = PTR_ERR(tsc->adc_regs);
413		dev_err(&pdev->dev, "failed to remap adc memory: %d\n", err);
414		return err;
415	}
416
417	tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");
418	if (IS_ERR(tsc->tsc_clk)) {
419		err = PTR_ERR(tsc->tsc_clk);
420		dev_err(&pdev->dev, "failed getting tsc clock: %d\n", err);
421		return err;
422	}
423
424	tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");
425	if (IS_ERR(tsc->adc_clk)) {
426		err = PTR_ERR(tsc->adc_clk);
427		dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);
428		return err;
429	}
430
431	tsc_irq = platform_get_irq(pdev, 0);
432	if (tsc_irq < 0) {
433		dev_err(&pdev->dev, "no tsc irq resource?\n");
434		return tsc_irq;
435	}
436
437	adc_irq = platform_get_irq(pdev, 1);
438	if (adc_irq < 0) {
439		dev_err(&pdev->dev, "no adc irq resource?\n");
440		return adc_irq;
441	}
442
443	err = devm_request_threaded_irq(tsc->dev, tsc_irq,
444					NULL, tsc_irq_fn, IRQF_ONESHOT,
445					dev_name(&pdev->dev), tsc);
446	if (err) {
447		dev_err(&pdev->dev,
448			"failed requesting tsc irq %d: %d\n",
449			tsc_irq, err);
450		return err;
451	}
452
453	err = devm_request_irq(tsc->dev, adc_irq, adc_irq_fn, 0,
454				dev_name(&pdev->dev), tsc);
455	if (err) {
456		dev_err(&pdev->dev,
457			"failed requesting adc irq %d: %d\n",
458			adc_irq, err);
459		return err;
460	}
461
462	err = of_property_read_u32(np, "measure-delay-time",
463				   &tsc->measure_delay_time);
464	if (err)
465		tsc->measure_delay_time = 0xffff;
466
467	err = of_property_read_u32(np, "pre-charge-time",
468				   &tsc->pre_charge_time);
469	if (err)
470		tsc->pre_charge_time = 0xfff;
471
472	err = of_property_read_u32(np, "touchscreen-average-samples",
473				   &average_samples);
474	if (err)
475		average_samples = 1;
476
477	switch (average_samples) {
478	case 1:
479		tsc->average_enable = false;
480		tsc->average_select = 0; /* value unused; initialize anyway */
481		break;
482	case 4:
483	case 8:
484	case 16:
485	case 32:
486		tsc->average_enable = true;
487		tsc->average_select = ilog2(average_samples) - 2;
488		break;
489	default:
490		dev_err(&pdev->dev,
491			"touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
492			average_samples);
493		return -EINVAL;
494	}
495
496	err = input_register_device(tsc->input);
497	if (err) {
498		dev_err(&pdev->dev,
499			"failed to register input device: %d\n", err);
500		return err;
501	}
502
503	platform_set_drvdata(pdev, tsc);
504	return 0;
505}
506
507static int __maybe_unused imx6ul_tsc_suspend(struct device *dev)
508{
509	struct platform_device *pdev = to_platform_device(dev);
510	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
511	struct input_dev *input_dev = tsc->input;
512
513	mutex_lock(&input_dev->mutex);
514
515	if (input_dev->users) {
516		imx6ul_tsc_disable(tsc);
517
518		clk_disable_unprepare(tsc->tsc_clk);
519		clk_disable_unprepare(tsc->adc_clk);
520	}
521
522	mutex_unlock(&input_dev->mutex);
523
524	return 0;
525}
526
527static int __maybe_unused imx6ul_tsc_resume(struct device *dev)
528{
529	struct platform_device *pdev = to_platform_device(dev);
530	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
531	struct input_dev *input_dev = tsc->input;
532	int retval = 0;
533
534	mutex_lock(&input_dev->mutex);
535
536	if (input_dev->users) {
537		retval = clk_prepare_enable(tsc->adc_clk);
538		if (retval)
539			goto out;
540
541		retval = clk_prepare_enable(tsc->tsc_clk);
542		if (retval) {
543			clk_disable_unprepare(tsc->adc_clk);
544			goto out;
545		}
546
547		retval = imx6ul_tsc_init(tsc);
548	}
549
550out:
551	mutex_unlock(&input_dev->mutex);
552	return retval;
553}
554
555static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
556			 imx6ul_tsc_suspend, imx6ul_tsc_resume);
557
558static const struct of_device_id imx6ul_tsc_match[] = {
559	{ .compatible = "fsl,imx6ul-tsc", },
560	{ /* sentinel */ }
561};
562MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
563
564static struct platform_driver imx6ul_tsc_driver = {
565	.driver		= {
566		.name	= "imx6ul-tsc",
567		.of_match_table	= imx6ul_tsc_match,
568		.pm	= &imx6ul_tsc_pm_ops,
569	},
570	.probe		= imx6ul_tsc_probe,
571};
572module_platform_driver(imx6ul_tsc_driver);
573
574MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");
575MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");
576MODULE_LICENSE("GPL v2");