1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * STMicroelectronics STMPE811 Touchscreen Driver
4  *
5  * (C) 2010 Luotao Fu <l.fu@pengutronix.de>
6  * All rights reserved.
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/sched.h>
12 #include <linux/interrupt.h>
13 #include <linux/device.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/input.h>
17 #include <linux/slab.h>
18 #include <linux/delay.h>
19 #include <linux/i2c.h>
20 #include <linux/workqueue.h>
21 
22 #include <linux/mfd/stmpe.h>
23 
24 /* Register layouts and functionalities are identical on all stmpexxx variants
25  * with touchscreen controller
26  */
27 #define STMPE_REG_INT_STA		0x0B
28 #define STMPE_REG_TSC_CTRL		0x40
29 #define STMPE_REG_TSC_CFG		0x41
30 #define STMPE_REG_FIFO_TH		0x4A
31 #define STMPE_REG_FIFO_STA		0x4B
32 #define STMPE_REG_FIFO_SIZE		0x4C
33 #define STMPE_REG_TSC_DATA_XYZ		0x52
34 #define STMPE_REG_TSC_FRACTION_Z	0x56
35 #define STMPE_REG_TSC_I_DRIVE		0x58
36 
37 #define OP_MOD_XYZ			0
38 
39 #define STMPE_TSC_CTRL_TSC_EN		(1<<0)
40 
41 #define STMPE_FIFO_STA_RESET		(1<<0)
42 
43 #define STMPE_IRQ_TOUCH_DET		0
44 
45 #define STMPE_TS_NAME			"stmpe-ts"
46 #define XY_MASK				0xfff
47 
48 /**
49  * struct stmpe_touch - stmpe811 touch screen controller state
50  * @stmpe: pointer back to STMPE MFD container
51  * @idev: registered input device
52  * @work: a work item used to scan the device
53  * @dev: a pointer back to the MFD cell struct device*
54  * @ave_ctrl: Sample average control
55  * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
56  * @touch_det_delay: Touch detect interrupt delay
57  * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
58  * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
59  * recommended is 3
60  * @settling: Panel driver settling time
61  * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
62  * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
63  * recommended is 2
64  * @fraction_z: Length of the fractional part in z
65  * (fraction_z ([0..7]) = Count of the fractional part)
66  * recommended is 7
67  * @i_drive: current limit value of the touchscreen drivers
68  * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
69  */
70 struct stmpe_touch {
71 	struct stmpe *stmpe;
72 	struct input_dev *idev;
73 	struct delayed_work work;
74 	struct device *dev;
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, msecs_to_jiffies(50));
168 
169 	return IRQ_HANDLED;
170 }
171 
172 static int stmpe_init_hw(struct stmpe_touch *ts)
173 {
174 	int ret;
175 	u8 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 	ret = stmpe811_adc_common_init(stmpe);
186 	if (ret) {
187 		stmpe_disable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
188 		return ret;
189 	}
190 
191 	tsc_cfg = STMPE_AVE_CTRL(ts->ave_ctrl) |
192 		  STMPE_DET_DELAY(ts->touch_det_delay) |
193 		  STMPE_SETTLING(ts->settling);
194 	tsc_cfg_mask = STMPE_AVE_CTRL(0xff) | STMPE_DET_DELAY(0xff) |
195 		       STMPE_SETTLING(0xff);
196 
197 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
198 	if (ret) {
199 		dev_err(dev, "Could not config touch\n");
200 		return ret;
201 	}
202 
203 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
204 			STMPE_FRACTION_Z(0xff), STMPE_FRACTION_Z(ts->fraction_z));
205 	if (ret) {
206 		dev_err(dev, "Could not config touch\n");
207 		return ret;
208 	}
209 
210 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
211 			STMPE_I_DRIVE(0xff), STMPE_I_DRIVE(ts->i_drive));
212 	if (ret) {
213 		dev_err(dev, "Could not config touch\n");
214 		return ret;
215 	}
216 
217 	/* set FIFO to 1 for single point reading */
218 	ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
219 	if (ret) {
220 		dev_err(dev, "Could not set FIFO\n");
221 		return ret;
222 	}
223 
224 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
225 			STMPE_OP_MODE(0xff), STMPE_OP_MODE(OP_MOD_XYZ));
226 	if (ret) {
227 		dev_err(dev, "Could not set mode\n");
228 		return ret;
229 	}
230 
231 	return 0;
232 }
233 
234 static int stmpe_ts_open(struct input_dev *dev)
235 {
236 	struct stmpe_touch *ts = input_get_drvdata(dev);
237 	int ret = 0;
238 
239 	ret = __stmpe_reset_fifo(ts->stmpe);
240 	if (ret)
241 		return ret;
242 
243 	return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
244 			STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
245 }
246 
247 static void stmpe_ts_close(struct input_dev *dev)
248 {
249 	struct stmpe_touch *ts = input_get_drvdata(dev);
250 
251 	cancel_delayed_work_sync(&ts->work);
252 
253 	stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
254 			STMPE_TSC_CTRL_TSC_EN, 0);
255 }
256 
257 static void stmpe_ts_get_platform_info(struct platform_device *pdev,
258 					struct stmpe_touch *ts)
259 {
260 	struct device_node *np = pdev->dev.of_node;
261 	u32 val;
262 
263 	if (np) {
264 		if (!of_property_read_u32(np, "st,sample-time", &val))
265 			ts->stmpe->sample_time = val;
266 		if (!of_property_read_u32(np, "st,mod-12b", &val))
267 			ts->stmpe->mod_12b = val;
268 		if (!of_property_read_u32(np, "st,ref-sel", &val))
269 			ts->stmpe->ref_sel = val;
270 		if (!of_property_read_u32(np, "st,adc-freq", &val))
271 			ts->stmpe->adc_freq = val;
272 		if (!of_property_read_u32(np, "st,ave-ctrl", &val))
273 			ts->ave_ctrl = val;
274 		if (!of_property_read_u32(np, "st,touch-det-delay", &val))
275 			ts->touch_det_delay = val;
276 		if (!of_property_read_u32(np, "st,settling", &val))
277 			ts->settling = val;
278 		if (!of_property_read_u32(np, "st,fraction-z", &val))
279 			ts->fraction_z = val;
280 		if (!of_property_read_u32(np, "st,i-drive", &val))
281 			ts->i_drive = val;
282 	}
283 }
284 
285 static int stmpe_input_probe(struct platform_device *pdev)
286 {
287 	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
288 	struct stmpe_touch *ts;
289 	struct input_dev *idev;
290 	int error;
291 	int ts_irq;
292 
293 	ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
294 	if (ts_irq < 0)
295 		return ts_irq;
296 
297 	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
298 	if (!ts)
299 		return -ENOMEM;
300 
301 	idev = devm_input_allocate_device(&pdev->dev);
302 	if (!idev)
303 		return -ENOMEM;
304 
305 	platform_set_drvdata(pdev, ts);
306 	ts->stmpe = stmpe;
307 	ts->idev = idev;
308 	ts->dev = &pdev->dev;
309 
310 	stmpe_ts_get_platform_info(pdev, ts);
311 
312 	INIT_DELAYED_WORK(&ts->work, stmpe_work);
313 
314 	error = devm_request_threaded_irq(&pdev->dev, ts_irq,
315 					  NULL, stmpe_ts_handler,
316 					  IRQF_ONESHOT, STMPE_TS_NAME, ts);
317 	if (error) {
318 		dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
319 		return error;
320 	}
321 
322 	error = stmpe_init_hw(ts);
323 	if (error)
324 		return error;
325 
326 	idev->name = STMPE_TS_NAME;
327 	idev->phys = STMPE_TS_NAME"/input0";
328 	idev->id.bustype = BUS_I2C;
329 
330 	idev->open = stmpe_ts_open;
331 	idev->close = stmpe_ts_close;
332 
333 	input_set_drvdata(idev, ts);
334 
335 	input_set_capability(idev, EV_KEY, BTN_TOUCH);
336 	input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
337 	input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
338 	input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
339 
340 	error = input_register_device(idev);
341 	if (error) {
342 		dev_err(&pdev->dev, "Could not register input device\n");
343 		return error;
344 	}
345 
346 	return 0;
347 }
348 
349 static int stmpe_ts_remove(struct platform_device *pdev)
350 {
351 	struct stmpe_touch *ts = platform_get_drvdata(pdev);
352 
353 	stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
354 
355 	return 0;
356 }
357 
358 static struct platform_driver stmpe_ts_driver = {
359 	.driver = {
360 		.name = STMPE_TS_NAME,
361 	},
362 	.probe = stmpe_input_probe,
363 	.remove = stmpe_ts_remove,
364 };
365 module_platform_driver(stmpe_ts_driver);
366 
367 static const struct of_device_id stmpe_ts_ids[] = {
368 	{ .compatible = "st,stmpe-ts", },
369 	{ },
370 };
371 MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
372 
373 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
374 MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
375 MODULE_LICENSE("GPL");
376