1/*
2 * STMicroelectronics STMPE811 Touchscreen Driver
3 *
4 * (C) 2010 Luotao Fu <l.fu@pengutronix.de>
5 * All rights reserved.
6 *
7 *  This program is free software; you can redistribute  it and/or modify it
8 *  under  the terms of  the GNU General  Public License as published by the
9 *  Free Software Foundation;  either version 2 of the  License, or (at your
10 *  option) any later version.
11 *
12 */
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/sched.h>
17#include <linux/interrupt.h>
18#include <linux/device.h>
19#include <linux/of.h>
20#include <linux/platform_device.h>
21#include <linux/input.h>
22#include <linux/slab.h>
23#include <linux/delay.h>
24#include <linux/i2c.h>
25#include <linux/workqueue.h>
26
27#include <linux/mfd/stmpe.h>
28
29/* Register layouts and functionalities are identical on all stmpexxx variants
30 * with touchscreen controller
31 */
32#define STMPE_REG_INT_STA		0x0B
33#define STMPE_REG_ADC_CTRL1		0x20
34#define STMPE_REG_ADC_CTRL2		0x21
35#define STMPE_REG_TSC_CTRL		0x40
36#define STMPE_REG_TSC_CFG		0x41
37#define STMPE_REG_FIFO_TH		0x4A
38#define STMPE_REG_FIFO_STA		0x4B
39#define STMPE_REG_FIFO_SIZE		0x4C
40#define STMPE_REG_TSC_DATA_XYZ		0x52
41#define STMPE_REG_TSC_FRACTION_Z	0x56
42#define STMPE_REG_TSC_I_DRIVE		0x58
43
44#define OP_MOD_XYZ			0
45
46#define STMPE_TSC_CTRL_TSC_EN		(1<<0)
47
48#define STMPE_FIFO_STA_RESET		(1<<0)
49
50#define STMPE_IRQ_TOUCH_DET		0
51
52#define SAMPLE_TIME(x)			((x & 0xf) << 4)
53#define MOD_12B(x)			((x & 0x1) << 3)
54#define REF_SEL(x)			((x & 0x1) << 1)
55#define ADC_FREQ(x)			(x & 0x3)
56#define AVE_CTRL(x)			((x & 0x3) << 6)
57#define DET_DELAY(x)			((x & 0x7) << 3)
58#define SETTLING(x)			(x & 0x7)
59#define FRACTION_Z(x)			(x & 0x7)
60#define I_DRIVE(x)			(x & 0x1)
61#define OP_MODE(x)			((x & 0x7) << 1)
62
63#define STMPE_TS_NAME			"stmpe-ts"
64#define XY_MASK				0xfff
65
66struct stmpe_touch {
67	struct stmpe *stmpe;
68	struct input_dev *idev;
69	struct delayed_work work;
70	struct device *dev;
71	u8 sample_time;
72	u8 mod_12b;
73	u8 ref_sel;
74	u8 adc_freq;
75	u8 ave_ctrl;
76	u8 touch_det_delay;
77	u8 settling;
78	u8 fraction_z;
79	u8 i_drive;
80};
81
82static int __stmpe_reset_fifo(struct stmpe *stmpe)
83{
84	int ret;
85
86	ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
87			STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
88	if (ret)
89		return ret;
90
91	return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
92			STMPE_FIFO_STA_RESET, 0);
93}
94
95static void stmpe_work(struct work_struct *work)
96{
97	int int_sta;
98	u32 timeout = 40;
99
100	struct stmpe_touch *ts =
101	    container_of(work, struct stmpe_touch, work.work);
102
103	int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
104
105	/*
106	 * touch_det sometimes get desasserted or just get stuck. This appears
107	 * to be a silicon bug, We still have to clearify this with the
108	 * manufacture. As a workaround We release the key anyway if the
109	 * touch_det keeps coming in after 4ms, while the FIFO contains no value
110	 * during the whole time.
111	 */
112	while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
113		timeout--;
114		int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
115		udelay(100);
116	}
117
118	/* reset the FIFO before we report release event */
119	__stmpe_reset_fifo(ts->stmpe);
120
121	input_report_abs(ts->idev, ABS_PRESSURE, 0);
122	input_report_key(ts->idev, BTN_TOUCH, 0);
123	input_sync(ts->idev);
124}
125
126static irqreturn_t stmpe_ts_handler(int irq, void *data)
127{
128	u8 data_set[4];
129	int x, y, z;
130	struct stmpe_touch *ts = data;
131
132	/*
133	 * Cancel scheduled polling for release if we have new value
134	 * available. Wait if the polling is already running.
135	 */
136	cancel_delayed_work_sync(&ts->work);
137
138	/*
139	 * The FIFO sometimes just crashes and stops generating interrupts. This
140	 * appears to be a silicon bug. We still have to clearify this with
141	 * the manufacture. As a workaround we disable the TSC while we are
142	 * collecting data and flush the FIFO after reading
143	 */
144	stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
145				STMPE_TSC_CTRL_TSC_EN, 0);
146
147	stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
148
149	x = (data_set[0] << 4) | (data_set[1] >> 4);
150	y = ((data_set[1] & 0xf) << 8) | data_set[2];
151	z = data_set[3];
152
153	input_report_abs(ts->idev, ABS_X, x);
154	input_report_abs(ts->idev, ABS_Y, y);
155	input_report_abs(ts->idev, ABS_PRESSURE, z);
156	input_report_key(ts->idev, BTN_TOUCH, 1);
157	input_sync(ts->idev);
158
159       /* flush the FIFO after we have read out our values. */
160	__stmpe_reset_fifo(ts->stmpe);
161
162	/* reenable the tsc */
163	stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
164			STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
165
166	/* start polling for touch_det to detect release */
167	schedule_delayed_work(&ts->work, msecs_to_jiffies(50));
168
169	return IRQ_HANDLED;
170}
171
172static int stmpe_init_hw(struct stmpe_touch *ts)
173{
174	int ret;
175	u8 adc_ctrl1, adc_ctrl1_mask, tsc_cfg, tsc_cfg_mask;
176	struct stmpe *stmpe = ts->stmpe;
177	struct device *dev = ts->dev;
178
179	ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
180	if (ret) {
181		dev_err(dev, "Could not enable clock for ADC and TS\n");
182		return ret;
183	}
184
185	adc_ctrl1 = SAMPLE_TIME(ts->sample_time) | MOD_12B(ts->mod_12b) |
186		REF_SEL(ts->ref_sel);
187	adc_ctrl1_mask = SAMPLE_TIME(0xff) | MOD_12B(0xff) | REF_SEL(0xff);
188
189	ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL1,
190			adc_ctrl1_mask, adc_ctrl1);
191	if (ret) {
192		dev_err(dev, "Could not setup ADC\n");
193		return ret;
194	}
195
196	ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL2,
197			ADC_FREQ(0xff), ADC_FREQ(ts->adc_freq));
198	if (ret) {
199		dev_err(dev, "Could not setup ADC\n");
200		return ret;
201	}
202
203	tsc_cfg = AVE_CTRL(ts->ave_ctrl) | DET_DELAY(ts->touch_det_delay) |
204			SETTLING(ts->settling);
205	tsc_cfg_mask = AVE_CTRL(0xff) | DET_DELAY(0xff) | SETTLING(0xff);
206
207	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
208	if (ret) {
209		dev_err(dev, "Could not config touch\n");
210		return ret;
211	}
212
213	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
214			FRACTION_Z(0xff), FRACTION_Z(ts->fraction_z));
215	if (ret) {
216		dev_err(dev, "Could not config touch\n");
217		return ret;
218	}
219
220	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
221			I_DRIVE(0xff), I_DRIVE(ts->i_drive));
222	if (ret) {
223		dev_err(dev, "Could not config touch\n");
224		return ret;
225	}
226
227	/* set FIFO to 1 for single point reading */
228	ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
229	if (ret) {
230		dev_err(dev, "Could not set FIFO\n");
231		return ret;
232	}
233
234	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
235			OP_MODE(0xff), OP_MODE(OP_MOD_XYZ));
236	if (ret) {
237		dev_err(dev, "Could not set mode\n");
238		return ret;
239	}
240
241	return 0;
242}
243
244static int stmpe_ts_open(struct input_dev *dev)
245{
246	struct stmpe_touch *ts = input_get_drvdata(dev);
247	int ret = 0;
248
249	ret = __stmpe_reset_fifo(ts->stmpe);
250	if (ret)
251		return ret;
252
253	return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
254			STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
255}
256
257static void stmpe_ts_close(struct input_dev *dev)
258{
259	struct stmpe_touch *ts = input_get_drvdata(dev);
260
261	cancel_delayed_work_sync(&ts->work);
262
263	stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
264			STMPE_TSC_CTRL_TSC_EN, 0);
265}
266
267static void stmpe_ts_get_platform_info(struct platform_device *pdev,
268					struct stmpe_touch *ts)
269{
270	struct device_node *np = pdev->dev.of_node;
271	u32 val;
272
273	if (np) {
274		if (!of_property_read_u32(np, "st,sample-time", &val))
275			ts->sample_time = val;
276		if (!of_property_read_u32(np, "st,mod-12b", &val))
277			ts->mod_12b = val;
278		if (!of_property_read_u32(np, "st,ref-sel", &val))
279			ts->ref_sel = val;
280		if (!of_property_read_u32(np, "st,adc-freq", &val))
281			ts->adc_freq = val;
282		if (!of_property_read_u32(np, "st,ave-ctrl", &val))
283			ts->ave_ctrl = val;
284		if (!of_property_read_u32(np, "st,touch-det-delay", &val))
285			ts->touch_det_delay = val;
286		if (!of_property_read_u32(np, "st,settling", &val))
287			ts->settling = val;
288		if (!of_property_read_u32(np, "st,fraction-z", &val))
289			ts->fraction_z = val;
290		if (!of_property_read_u32(np, "st,i-drive", &val))
291			ts->i_drive = val;
292	}
293}
294
295static int stmpe_input_probe(struct platform_device *pdev)
296{
297	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
298	struct stmpe_touch *ts;
299	struct input_dev *idev;
300	int error;
301	int ts_irq;
302
303	ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
304	if (ts_irq < 0)
305		return ts_irq;
306
307	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
308	if (!ts)
309		return -ENOMEM;
310
311	idev = devm_input_allocate_device(&pdev->dev);
312	if (!idev)
313		return -ENOMEM;
314
315	platform_set_drvdata(pdev, ts);
316	ts->stmpe = stmpe;
317	ts->idev = idev;
318	ts->dev = &pdev->dev;
319
320	stmpe_ts_get_platform_info(pdev, ts);
321
322	INIT_DELAYED_WORK(&ts->work, stmpe_work);
323
324	error = devm_request_threaded_irq(&pdev->dev, ts_irq,
325					  NULL, stmpe_ts_handler,
326					  IRQF_ONESHOT, STMPE_TS_NAME, ts);
327	if (error) {
328		dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
329		return error;
330	}
331
332	error = stmpe_init_hw(ts);
333	if (error)
334		return error;
335
336	idev->name = STMPE_TS_NAME;
337	idev->phys = STMPE_TS_NAME"/input0";
338	idev->id.bustype = BUS_I2C;
339
340	idev->open = stmpe_ts_open;
341	idev->close = stmpe_ts_close;
342
343	input_set_drvdata(idev, ts);
344
345	input_set_capability(idev, EV_KEY, BTN_TOUCH);
346	input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
347	input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
348	input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
349
350	error = input_register_device(idev);
351	if (error) {
352		dev_err(&pdev->dev, "Could not register input device\n");
353		return error;
354	}
355
356	return 0;
357}
358
359static int stmpe_ts_remove(struct platform_device *pdev)
360{
361	struct stmpe_touch *ts = platform_get_drvdata(pdev);
362
363	stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
364
365	return 0;
366}
367
368static struct platform_driver stmpe_ts_driver = {
369	.driver = {
370		.name = STMPE_TS_NAME,
371	},
372	.probe = stmpe_input_probe,
373	.remove = stmpe_ts_remove,
374};
375module_platform_driver(stmpe_ts_driver);
376
377static const struct of_device_id stmpe_ts_ids[] = {
378	{ .compatible = "st,stmpe-ts", },
379	{ },
380};
381MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
382
383MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
384MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
385MODULE_LICENSE("GPL");
386