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