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 */
72struct 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
85static 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
98static 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
129static 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
174static 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
236static 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
249static 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
259static 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
287static 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
353static void 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
360static struct platform_driver stmpe_ts_driver = {
361	.driver = {
362		.name = STMPE_TS_NAME,
363	},
364	.probe = stmpe_input_probe,
365	.remove_new = stmpe_ts_remove,
366};
367module_platform_driver(stmpe_ts_driver);
368
369static const struct of_device_id stmpe_ts_ids[] = {
370	{ .compatible = "st,stmpe-ts", },
371	{ },
372};
373MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
374
375MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
376MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
377MODULE_LICENSE("GPL");
378