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/input/touchscreen.h>
18 #include <linux/slab.h>
19 #include <linux/delay.h>
20 #include <linux/i2c.h>
21 #include <linux/workqueue.h>
22 
23 #include <linux/mfd/stmpe.h>
24 
25 /* Register layouts and functionalities are identical on all stmpexxx variants
26  * with touchscreen controller
27  */
28 #define STMPE_REG_INT_STA		0x0B
29 #define STMPE_REG_TSC_CTRL		0x40
30 #define STMPE_REG_TSC_CFG		0x41
31 #define STMPE_REG_FIFO_TH		0x4A
32 #define STMPE_REG_FIFO_STA		0x4B
33 #define STMPE_REG_FIFO_SIZE		0x4C
34 #define STMPE_REG_TSC_DATA_XYZ		0x52
35 #define STMPE_REG_TSC_FRACTION_Z	0x56
36 #define STMPE_REG_TSC_I_DRIVE		0x58
37 
38 #define OP_MOD_XYZ			0
39 
40 #define STMPE_TSC_CTRL_TSC_EN		(1<<0)
41 
42 #define STMPE_FIFO_STA_RESET		(1<<0)
43 
44 #define STMPE_IRQ_TOUCH_DET		0
45 
46 #define STMPE_TS_NAME			"stmpe-ts"
47 #define XY_MASK				0xfff
48 
49 /**
50  * struct stmpe_touch - stmpe811 touch screen controller state
51  * @stmpe: pointer back to STMPE MFD container
52  * @idev: registered input device
53  * @work: a work item used to scan the device
54  * @dev: a pointer back to the MFD cell struct device*
55  * @prop: Touchscreen properties
56  * @ave_ctrl: Sample average control
57  * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
58  * @touch_det_delay: Touch detect interrupt delay
59  * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
60  * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
61  * recommended is 3
62  * @settling: Panel driver settling time
63  * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
64  * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
65  * recommended is 2
66  * @fraction_z: Length of the fractional part in z
67  * (fraction_z ([0..7]) = Count of the fractional part)
68  * recommended is 7
69  * @i_drive: current limit value of the touchscreen drivers
70  * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
71  */
72 struct stmpe_touch {
73 	struct stmpe *stmpe;
74 	struct input_dev *idev;
75 	struct delayed_work work;
76 	struct device *dev;
77 	struct touchscreen_properties prop;
78 	u8 ave_ctrl;
79 	u8 touch_det_delay;
80 	u8 settling;
81 	u8 fraction_z;
82 	u8 i_drive;
83 };
84 
85 static int __stmpe_reset_fifo(struct stmpe *stmpe)
86 {
87 	int ret;
88 
89 	ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
90 			STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
91 	if (ret)
92 		return ret;
93 
94 	return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
95 			STMPE_FIFO_STA_RESET, 0);
96 }
97 
98 static void stmpe_work(struct work_struct *work)
99 {
100 	int int_sta;
101 	u32 timeout = 40;
102 
103 	struct stmpe_touch *ts =
104 	    container_of(work, struct stmpe_touch, work.work);
105 
106 	int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
107 
108 	/*
109 	 * touch_det sometimes get desasserted or just get stuck. This appears
110 	 * to be a silicon bug, We still have to clearify this with the
111 	 * manufacture. As a workaround We release the key anyway if the
112 	 * touch_det keeps coming in after 4ms, while the FIFO contains no value
113 	 * during the whole time.
114 	 */
115 	while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
116 		timeout--;
117 		int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
118 		udelay(100);
119 	}
120 
121 	/* reset the FIFO before we report release event */
122 	__stmpe_reset_fifo(ts->stmpe);
123 
124 	input_report_abs(ts->idev, ABS_PRESSURE, 0);
125 	input_report_key(ts->idev, BTN_TOUCH, 0);
126 	input_sync(ts->idev);
127 }
128 
129 static irqreturn_t stmpe_ts_handler(int irq, void *data)
130 {
131 	u8 data_set[4];
132 	int x, y, z;
133 	struct stmpe_touch *ts = data;
134 
135 	/*
136 	 * Cancel scheduled polling for release if we have new value
137 	 * available. Wait if the polling is already running.
138 	 */
139 	cancel_delayed_work_sync(&ts->work);
140 
141 	/*
142 	 * The FIFO sometimes just crashes and stops generating interrupts. This
143 	 * appears to be a silicon bug. We still have to clearify this with
144 	 * the manufacture. As a workaround we disable the TSC while we are
145 	 * collecting data and flush the FIFO after reading
146 	 */
147 	stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
148 				STMPE_TSC_CTRL_TSC_EN, 0);
149 
150 	stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
151 
152 	x = (data_set[0] << 4) | (data_set[1] >> 4);
153 	y = ((data_set[1] & 0xf) << 8) | data_set[2];
154 	z = data_set[3];
155 
156 	touchscreen_report_pos(ts->idev, &ts->prop, x, y, false);
157 	input_report_abs(ts->idev, ABS_PRESSURE, z);
158 	input_report_key(ts->idev, BTN_TOUCH, 1);
159 	input_sync(ts->idev);
160 
161        /* flush the FIFO after we have read out our values. */
162 	__stmpe_reset_fifo(ts->stmpe);
163 
164 	/* reenable the tsc */
165 	stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
166 			STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
167 
168 	/* start polling for touch_det to detect release */
169 	schedule_delayed_work(&ts->work, msecs_to_jiffies(50));
170 
171 	return IRQ_HANDLED;
172 }
173 
174 static int stmpe_init_hw(struct stmpe_touch *ts)
175 {
176 	int ret;
177 	u8 tsc_cfg, tsc_cfg_mask;
178 	struct stmpe *stmpe = ts->stmpe;
179 	struct device *dev = ts->dev;
180 
181 	ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
182 	if (ret) {
183 		dev_err(dev, "Could not enable clock for ADC and TS\n");
184 		return ret;
185 	}
186 
187 	ret = stmpe811_adc_common_init(stmpe);
188 	if (ret) {
189 		stmpe_disable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
190 		return ret;
191 	}
192 
193 	tsc_cfg = STMPE_AVE_CTRL(ts->ave_ctrl) |
194 		  STMPE_DET_DELAY(ts->touch_det_delay) |
195 		  STMPE_SETTLING(ts->settling);
196 	tsc_cfg_mask = STMPE_AVE_CTRL(0xff) | STMPE_DET_DELAY(0xff) |
197 		       STMPE_SETTLING(0xff);
198 
199 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
200 	if (ret) {
201 		dev_err(dev, "Could not config touch\n");
202 		return ret;
203 	}
204 
205 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
206 			STMPE_FRACTION_Z(0xff), STMPE_FRACTION_Z(ts->fraction_z));
207 	if (ret) {
208 		dev_err(dev, "Could not config touch\n");
209 		return ret;
210 	}
211 
212 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
213 			STMPE_I_DRIVE(0xff), STMPE_I_DRIVE(ts->i_drive));
214 	if (ret) {
215 		dev_err(dev, "Could not config touch\n");
216 		return ret;
217 	}
218 
219 	/* set FIFO to 1 for single point reading */
220 	ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
221 	if (ret) {
222 		dev_err(dev, "Could not set FIFO\n");
223 		return ret;
224 	}
225 
226 	ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
227 			STMPE_OP_MODE(0xff), STMPE_OP_MODE(OP_MOD_XYZ));
228 	if (ret) {
229 		dev_err(dev, "Could not set mode\n");
230 		return ret;
231 	}
232 
233 	return 0;
234 }
235 
236 static int stmpe_ts_open(struct input_dev *dev)
237 {
238 	struct stmpe_touch *ts = input_get_drvdata(dev);
239 	int ret = 0;
240 
241 	ret = __stmpe_reset_fifo(ts->stmpe);
242 	if (ret)
243 		return ret;
244 
245 	return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
246 			STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
247 }
248 
249 static void stmpe_ts_close(struct input_dev *dev)
250 {
251 	struct stmpe_touch *ts = input_get_drvdata(dev);
252 
253 	cancel_delayed_work_sync(&ts->work);
254 
255 	stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
256 			STMPE_TSC_CTRL_TSC_EN, 0);
257 }
258 
259 static void stmpe_ts_get_platform_info(struct platform_device *pdev,
260 					struct stmpe_touch *ts)
261 {
262 	struct device_node *np = pdev->dev.of_node;
263 	u32 val;
264 
265 	if (np) {
266 		if (!of_property_read_u32(np, "st,sample-time", &val))
267 			ts->stmpe->sample_time = val;
268 		if (!of_property_read_u32(np, "st,mod-12b", &val))
269 			ts->stmpe->mod_12b = val;
270 		if (!of_property_read_u32(np, "st,ref-sel", &val))
271 			ts->stmpe->ref_sel = val;
272 		if (!of_property_read_u32(np, "st,adc-freq", &val))
273 			ts->stmpe->adc_freq = val;
274 		if (!of_property_read_u32(np, "st,ave-ctrl", &val))
275 			ts->ave_ctrl = val;
276 		if (!of_property_read_u32(np, "st,touch-det-delay", &val))
277 			ts->touch_det_delay = val;
278 		if (!of_property_read_u32(np, "st,settling", &val))
279 			ts->settling = val;
280 		if (!of_property_read_u32(np, "st,fraction-z", &val))
281 			ts->fraction_z = val;
282 		if (!of_property_read_u32(np, "st,i-drive", &val))
283 			ts->i_drive = val;
284 	}
285 }
286 
287 static int stmpe_input_probe(struct platform_device *pdev)
288 {
289 	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
290 	struct stmpe_touch *ts;
291 	struct input_dev *idev;
292 	int error;
293 	int ts_irq;
294 
295 	ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
296 	if (ts_irq < 0)
297 		return ts_irq;
298 
299 	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
300 	if (!ts)
301 		return -ENOMEM;
302 
303 	idev = devm_input_allocate_device(&pdev->dev);
304 	if (!idev)
305 		return -ENOMEM;
306 
307 	platform_set_drvdata(pdev, ts);
308 	ts->stmpe = stmpe;
309 	ts->idev = idev;
310 	ts->dev = &pdev->dev;
311 
312 	stmpe_ts_get_platform_info(pdev, ts);
313 
314 	INIT_DELAYED_WORK(&ts->work, stmpe_work);
315 
316 	error = devm_request_threaded_irq(&pdev->dev, ts_irq,
317 					  NULL, stmpe_ts_handler,
318 					  IRQF_ONESHOT, STMPE_TS_NAME, ts);
319 	if (error) {
320 		dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
321 		return error;
322 	}
323 
324 	error = stmpe_init_hw(ts);
325 	if (error)
326 		return error;
327 
328 	idev->name = STMPE_TS_NAME;
329 	idev->phys = STMPE_TS_NAME"/input0";
330 	idev->id.bustype = BUS_I2C;
331 
332 	idev->open = stmpe_ts_open;
333 	idev->close = stmpe_ts_close;
334 
335 	input_set_drvdata(idev, ts);
336 
337 	input_set_capability(idev, EV_KEY, BTN_TOUCH);
338 	input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
339 	input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
340 	input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
341 
342 	touchscreen_parse_properties(idev, false, &ts->prop);
343 
344 	error = input_register_device(idev);
345 	if (error) {
346 		dev_err(&pdev->dev, "Could not register input device\n");
347 		return error;
348 	}
349 
350 	return 0;
351 }
352 
353 static int stmpe_ts_remove(struct platform_device *pdev)
354 {
355 	struct stmpe_touch *ts = platform_get_drvdata(pdev);
356 
357 	stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
358 
359 	return 0;
360 }
361 
362 static struct platform_driver stmpe_ts_driver = {
363 	.driver = {
364 		.name = STMPE_TS_NAME,
365 	},
366 	.probe = stmpe_input_probe,
367 	.remove = stmpe_ts_remove,
368 };
369 module_platform_driver(stmpe_ts_driver);
370 
371 static const struct of_device_id stmpe_ts_ids[] = {
372 	{ .compatible = "st,stmpe-ts", },
373 	{ },
374 };
375 MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
376 
377 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
378 MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
379 MODULE_LICENSE("GPL");
380