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 */
70struct 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
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 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
234static 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
247static 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
257static 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
285static 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
349static 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
358static 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};
365module_platform_driver(stmpe_ts_driver);
366
367static const struct of_device_id stmpe_ts_ids[] = {
368	{ .compatible = "st,stmpe-ts", },
369	{ },
370};
371MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
372
373MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
374MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
375MODULE_LICENSE("GPL");
376