1// SPDX-License-Identifier: GPL-2.0-only
  2
  3#include <linux/bits.h>
  4#include <linux/delay.h>
  5#include <linux/i2c.h>
  6#include <linux/input.h>
  7#include <linux/input/mt.h>
  8#include <linux/input/touchscreen.h>
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/property.h>
 12#include <linux/regulator/consumer.h>
 13
 14#define IST3038C_HIB_ACCESS		(0x800B << 16)
 15#define IST3038C_DIRECT_ACCESS		BIT(31)
 16#define IST3038C_REG_CHIPID		0x40001000
 17#define IST3038C_REG_HIB_BASE		0x30000100
 18#define IST3038C_REG_TOUCH_STATUS	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS)
 19#define IST3038C_REG_TOUCH_COORD	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS | 0x8)
 20#define IST3038C_REG_INTR_MESSAGE	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS | 0x4)
 21#define IST3038C_WHOAMI			0x38c
 22#define IST3038C_CHIP_ON_DELAY_MS	60
 23#define IST3038C_I2C_RETRY_COUNT	3
 24#define IST3038C_MAX_FINGER_NUM		10
 25#define IST3038C_X_MASK			GENMASK(23, 12)
 26#define IST3038C_X_SHIFT		12
 27#define IST3038C_Y_MASK			GENMASK(11, 0)
 28#define IST3038C_AREA_MASK		GENMASK(27, 24)
 29#define IST3038C_AREA_SHIFT		24
 30#define IST3038C_FINGER_COUNT_MASK	GENMASK(15, 12)
 31#define IST3038C_FINGER_COUNT_SHIFT	12
 32#define IST3038C_FINGER_STATUS_MASK	GENMASK(9, 0)
 33
 34struct imagis_ts {
 35	struct i2c_client *client;
 36	struct input_dev *input_dev;
 37	struct touchscreen_properties prop;
 38	struct regulator_bulk_data supplies[2];
 39};
 40
 41static int imagis_i2c_read_reg(struct imagis_ts *ts,
 42			       unsigned int reg, u32 *data)
 43{
 44	__be32 ret_be;
 45	__be32 reg_be = cpu_to_be32(reg);
 46	struct i2c_msg msg[] = {
 47		{
 48			.addr = ts->client->addr,
 49			.flags = 0,
 50			.buf = (unsigned char *)&reg_be,
 51			.len = sizeof(reg_be),
 52		}, {
 53			.addr = ts->client->addr,
 54			.flags = I2C_M_RD,
 55			.buf = (unsigned char *)&ret_be,
 56			.len = sizeof(ret_be),
 57		},
 58	};
 59	int ret, error;
 60	int retry = IST3038C_I2C_RETRY_COUNT;
 61
 62	/* Retry in case the controller fails to respond */
 63	do {
 64		ret = i2c_transfer(ts->client->adapter, msg, ARRAY_SIZE(msg));
 65		if (ret == ARRAY_SIZE(msg)) {
 66			*data = be32_to_cpu(ret_be);
 67			return 0;
 68		}
 69
 70		error = ret < 0 ? ret : -EIO;
 71		dev_err(&ts->client->dev,
 72			"%s - i2c_transfer failed: %d (%d)\n",
 73			__func__, error, ret);
 74	} while (--retry);
 75
 76	return error;
 77}
 78
 79static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 80{
 81	struct imagis_ts *ts = dev_id;
 82	u32 intr_message, finger_status;
 83	unsigned int finger_count, finger_pressed;
 84	int i;
 85	int error;
 86
 87	error = imagis_i2c_read_reg(ts, IST3038C_REG_INTR_MESSAGE,
 88				    &intr_message);
 89	if (error) {
 90		dev_err(&ts->client->dev,
 91			"failed to read the interrupt message: %d\n", error);
 92		goto out;
 93	}
 94
 95	finger_count = (intr_message & IST3038C_FINGER_COUNT_MASK) >>
 96				IST3038C_FINGER_COUNT_SHIFT;
 97	if (finger_count > IST3038C_MAX_FINGER_NUM) {
 98		dev_err(&ts->client->dev,
 99			"finger count %d is more than maximum supported\n",
100			finger_count);
101		goto out;
102	}
103
104	finger_pressed = intr_message & IST3038C_FINGER_STATUS_MASK;
105
106	for (i = 0; i < finger_count; i++) {
107		error = imagis_i2c_read_reg(ts,
108					    IST3038C_REG_TOUCH_COORD + (i * 4),
109					    &finger_status);
110		if (error) {
111			dev_err(&ts->client->dev,
112				"failed to read coordinates for finger %d: %d\n",
113				i, error);
114			goto out;
115		}
116
117		input_mt_slot(ts->input_dev, i);
118		input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER,
119					   finger_pressed & BIT(i));
120		touchscreen_report_pos(ts->input_dev, &ts->prop,
121				       (finger_status & IST3038C_X_MASK) >>
122						IST3038C_X_SHIFT,
123				       finger_status & IST3038C_Y_MASK, 1);
124		input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR,
125				 (finger_status & IST3038C_AREA_MASK) >>
126					IST3038C_AREA_SHIFT);
127	}
128
129	input_mt_sync_frame(ts->input_dev);
130	input_sync(ts->input_dev);
131
132out:
133	return IRQ_HANDLED;
134}
135
136static void imagis_power_off(void *_ts)
137{
138	struct imagis_ts *ts = _ts;
139
140	regulator_bulk_disable(ARRAY_SIZE(ts->supplies), ts->supplies);
141}
142
143static int imagis_power_on(struct imagis_ts *ts)
144{
145	int error;
146
147	error = regulator_bulk_enable(ARRAY_SIZE(ts->supplies), ts->supplies);
148	if (error)
149		return error;
150
151	msleep(IST3038C_CHIP_ON_DELAY_MS);
152
153	return 0;
154}
155
156static int imagis_start(struct imagis_ts *ts)
157{
158	int error;
159
160	error = imagis_power_on(ts);
161	if (error)
162		return error;
163
164	enable_irq(ts->client->irq);
165
166	return 0;
167}
168
169static int imagis_stop(struct imagis_ts *ts)
170{
171	disable_irq(ts->client->irq);
172
173	imagis_power_off(ts);
174
175	return 0;
176}
177
178static int imagis_input_open(struct input_dev *dev)
179{
180	struct imagis_ts *ts = input_get_drvdata(dev);
181
182	return imagis_start(ts);
183}
184
185static void imagis_input_close(struct input_dev *dev)
186{
187	struct imagis_ts *ts = input_get_drvdata(dev);
188
189	imagis_stop(ts);
190}
191
192static int imagis_init_input_dev(struct imagis_ts *ts)
193{
194	struct input_dev *input_dev;
195	int error;
196
197	input_dev = devm_input_allocate_device(&ts->client->dev);
198	if (!input_dev)
199		return -ENOMEM;
200
201	ts->input_dev = input_dev;
202
203	input_dev->name = "Imagis capacitive touchscreen";
204	input_dev->phys = "input/ts";
205	input_dev->id.bustype = BUS_I2C;
206	input_dev->open = imagis_input_open;
207	input_dev->close = imagis_input_close;
208
209	input_set_drvdata(input_dev, ts);
210
211	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
212	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
213	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
214
215	touchscreen_parse_properties(input_dev, true, &ts->prop);
216	if (!ts->prop.max_x || !ts->prop.max_y) {
217		dev_err(&ts->client->dev,
218			"Touchscreen-size-x and/or touchscreen-size-y not set in dts\n");
219		return -EINVAL;
220	}
221
222	error = input_mt_init_slots(input_dev,
223				    IST3038C_MAX_FINGER_NUM,
224				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
225	if (error) {
226		dev_err(&ts->client->dev,
227			"Failed to initialize MT slots: %d", error);
228		return error;
229	}
230
231	error = input_register_device(input_dev);
232	if (error) {
233		dev_err(&ts->client->dev,
234			"Failed to register input device: %d", error);
235		return error;
236	}
237
238	return 0;
239}
240
241static int imagis_init_regulators(struct imagis_ts *ts)
242{
243	struct i2c_client *client = ts->client;
244
245	ts->supplies[0].supply = "vdd";
246	ts->supplies[1].supply = "vddio";
247	return devm_regulator_bulk_get(&client->dev,
248				       ARRAY_SIZE(ts->supplies),
249				       ts->supplies);
250}
251
252static int imagis_probe(struct i2c_client *i2c)
253{
254	struct device *dev = &i2c->dev;
255	struct imagis_ts *ts;
256	int chip_id, error;
257
258	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
259	if (!ts)
260		return -ENOMEM;
261
262	ts->client = i2c;
263
264	error = imagis_init_regulators(ts);
265	if (error) {
266		dev_err(dev, "regulator init error: %d\n", error);
267		return error;
268	}
269
270	error = imagis_power_on(ts);
271	if (error) {
272		dev_err(dev, "failed to enable regulators: %d\n", error);
273		return error;
274	}
275
276	error = devm_add_action_or_reset(dev, imagis_power_off, ts);
277	if (error) {
278		dev_err(dev, "failed to install poweroff action: %d\n", error);
279		return error;
280	}
281
282	error = imagis_i2c_read_reg(ts,
283			IST3038C_REG_CHIPID | IST3038C_DIRECT_ACCESS,
284			&chip_id);
285	if (error) {
286		dev_err(dev, "chip ID read failure: %d\n", error);
287		return error;
288	}
289
290	if (chip_id != IST3038C_WHOAMI) {
291		dev_err(dev, "unknown chip ID: 0x%x\n", chip_id);
292		return -EINVAL;
293	}
294
295	error = devm_request_threaded_irq(dev, i2c->irq,
296					  NULL, imagis_interrupt,
297					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
298					  "imagis-touchscreen", ts);
299	if (error) {
300		dev_err(dev, "IRQ %d allocation failure: %d\n",
301			i2c->irq, error);
302		return error;
303	}
304
305	error = imagis_init_input_dev(ts);
306	if (error)
307		return error;
308
309	return 0;
310}
311
312static int imagis_suspend(struct device *dev)
313{
314	struct i2c_client *client = to_i2c_client(dev);
315	struct imagis_ts *ts = i2c_get_clientdata(client);
316	int retval = 0;
317
318	mutex_lock(&ts->input_dev->mutex);
319
320	if (input_device_enabled(ts->input_dev))
321		retval = imagis_stop(ts);
322
323	mutex_unlock(&ts->input_dev->mutex);
324
325	return retval;
326}
327
328static int imagis_resume(struct device *dev)
329{
330	struct i2c_client *client = to_i2c_client(dev);
331	struct imagis_ts *ts = i2c_get_clientdata(client);
332	int retval = 0;
333
334	mutex_lock(&ts->input_dev->mutex);
335
336	if (input_device_enabled(ts->input_dev))
337		retval = imagis_start(ts);
338
339	mutex_unlock(&ts->input_dev->mutex);
340
341	return retval;
342}
343
344static DEFINE_SIMPLE_DEV_PM_OPS(imagis_pm_ops, imagis_suspend, imagis_resume);
345
346#ifdef CONFIG_OF
347static const struct of_device_id imagis_of_match[] = {
348	{ .compatible = "imagis,ist3038c", },
349	{ },
350};
351MODULE_DEVICE_TABLE(of, imagis_of_match);
352#endif
353
354static struct i2c_driver imagis_ts_driver = {
355	.driver = {
356		.name = "imagis-touchscreen",
357		.pm = pm_sleep_ptr(&imagis_pm_ops),
358		.of_match_table = of_match_ptr(imagis_of_match),
359	},
360	.probe = imagis_probe,
361};
362
363module_i2c_driver(imagis_ts_driver);
364
365MODULE_DESCRIPTION("Imagis IST3038C Touchscreen Driver");
366MODULE_AUTHOR("Markuss Broks <markuss.broks@gmail.com>");
367MODULE_LICENSE("GPL");