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 
66 struct 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 
82 static 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 
95 static 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 
126 static 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, HZ / 50);
168 
169 	return IRQ_HANDLED;
170 }
171 
172 static 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 
244 static 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 
257 static 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 
267 static void stmpe_ts_get_platform_info(struct platform_device *pdev,
268 					struct stmpe_touch *ts)
269 {
270 	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
271 	struct device_node *np = pdev->dev.of_node;
272 	struct stmpe_ts_platform_data *ts_pdata = NULL;
273 
274 	ts->stmpe = stmpe;
275 
276 	if (stmpe->pdata && stmpe->pdata->ts) {
277 		ts_pdata = stmpe->pdata->ts;
278 
279 		ts->sample_time = ts_pdata->sample_time;
280 		ts->mod_12b = ts_pdata->mod_12b;
281 		ts->ref_sel = ts_pdata->ref_sel;
282 		ts->adc_freq = ts_pdata->adc_freq;
283 		ts->ave_ctrl = ts_pdata->ave_ctrl;
284 		ts->touch_det_delay = ts_pdata->touch_det_delay;
285 		ts->settling = ts_pdata->settling;
286 		ts->fraction_z = ts_pdata->fraction_z;
287 		ts->i_drive = ts_pdata->i_drive;
288 	} else if (np) {
289 		u32 val;
290 
291 		if (!of_property_read_u32(np, "st,sample-time", &val))
292 			ts->sample_time = val;
293 		if (!of_property_read_u32(np, "st,mod-12b", &val))
294 			ts->mod_12b = val;
295 		if (!of_property_read_u32(np, "st,ref-sel", &val))
296 			ts->ref_sel = val;
297 		if (!of_property_read_u32(np, "st,adc-freq", &val))
298 			ts->adc_freq = val;
299 		if (!of_property_read_u32(np, "st,ave-ctrl", &val))
300 			ts->ave_ctrl = val;
301 		if (!of_property_read_u32(np, "st,touch-det-delay", &val))
302 			ts->touch_det_delay = val;
303 		if (!of_property_read_u32(np, "st,settling", &val))
304 			ts->settling = val;
305 		if (!of_property_read_u32(np, "st,fraction-z", &val))
306 			ts->fraction_z = val;
307 		if (!of_property_read_u32(np, "st,i-drive", &val))
308 			ts->i_drive = val;
309 	}
310 }
311 
312 static int stmpe_input_probe(struct platform_device *pdev)
313 {
314 	struct stmpe_touch *ts;
315 	struct input_dev *idev;
316 	int error;
317 	int ts_irq;
318 
319 	ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
320 	if (ts_irq < 0)
321 		return ts_irq;
322 
323 	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
324 	if (!ts)
325 		return -ENOMEM;
326 
327 	idev = devm_input_allocate_device(&pdev->dev);
328 	if (!idev)
329 		return -ENOMEM;
330 
331 	platform_set_drvdata(pdev, ts);
332 	ts->idev = idev;
333 	ts->dev = &pdev->dev;
334 
335 	stmpe_ts_get_platform_info(pdev, ts);
336 
337 	INIT_DELAYED_WORK(&ts->work, stmpe_work);
338 
339 	error = devm_request_threaded_irq(&pdev->dev, ts_irq,
340 					  NULL, stmpe_ts_handler,
341 					  IRQF_ONESHOT, STMPE_TS_NAME, ts);
342 	if (error) {
343 		dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
344 		return error;
345 	}
346 
347 	error = stmpe_init_hw(ts);
348 	if (error)
349 		return error;
350 
351 	idev->name = STMPE_TS_NAME;
352 	idev->phys = STMPE_TS_NAME"/input0";
353 	idev->id.bustype = BUS_I2C;
354 	idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
355 	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
356 
357 	idev->open = stmpe_ts_open;
358 	idev->close = stmpe_ts_close;
359 
360 	input_set_drvdata(idev, ts);
361 
362 	input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
363 	input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
364 	input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
365 
366 	error = input_register_device(idev);
367 	if (error) {
368 		dev_err(&pdev->dev, "Could not register input device\n");
369 		return error;
370 	}
371 
372 	return 0;
373 }
374 
375 static int stmpe_ts_remove(struct platform_device *pdev)
376 {
377 	struct stmpe_touch *ts = platform_get_drvdata(pdev);
378 
379 	stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
380 
381 	return 0;
382 }
383 
384 static struct platform_driver stmpe_ts_driver = {
385 	.driver = {
386 		   .name = STMPE_TS_NAME,
387 		   },
388 	.probe = stmpe_input_probe,
389 	.remove = stmpe_ts_remove,
390 };
391 module_platform_driver(stmpe_ts_driver);
392 
393 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
394 MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
395 MODULE_LICENSE("GPL");
396 MODULE_ALIAS("platform:" STMPE_TS_NAME);
397