1/*
  2 *  Driver for Ntrig/Microsoft Touchscreens over SPI
  3 *
  4 *  Copyright (c) 2016 Red Hat Inc.
  5 */
  6
  7/*
  8 * This program is free software; you can redistribute it and/or modify it
  9 * under the terms of the GNU General Public License as published by the Free
 10 * Software Foundation; version 2 of the License.
 11 */
 12
 13#include <linux/kernel.h>
 14
 15#include <linux/delay.h>
 16#include <linux/gpio/consumer.h>
 17#include <linux/input.h>
 18#include <linux/input/mt.h>
 19#include <linux/interrupt.h>
 20#include <linux/module.h>
 21#include <linux/slab.h>
 22#include <linux/spi/spi.h>
 23#include <linux/acpi.h>
 24
 25#include <asm/unaligned.h>
 26
 27#define SURFACE3_PACKET_SIZE	264
 28
 29#define SURFACE3_REPORT_TOUCH	0xd2
 30#define SURFACE3_REPORT_PEN	0x16
 31
 32struct surface3_ts_data {
 33	struct spi_device *spi;
 34	struct gpio_desc *gpiod_rst[2];
 35	struct input_dev *input_dev;
 36	struct input_dev *pen_input_dev;
 37	int pen_tool;
 38
 39	u8 rd_buf[SURFACE3_PACKET_SIZE]		____cacheline_aligned;
 40};
 41
 42struct surface3_ts_data_finger {
 43	u8 status;
 44	__le16 tracking_id;
 45	__le16 x;
 46	__le16 cx;
 47	__le16 y;
 48	__le16 cy;
 49	__le16 width;
 50	__le16 height;
 51	u32 padding;
 52} __packed;
 53
 54struct surface3_ts_data_pen {
 55	u8 status;
 56	__le16 x;
 57	__le16 y;
 58	__le16 pressure;
 59	u8 padding;
 60} __packed;
 61
 62static int surface3_spi_read(struct surface3_ts_data *ts_data)
 63{
 64	struct spi_device *spi = ts_data->spi;
 65
 66	memset(ts_data->rd_buf, 0, sizeof(ts_data->rd_buf));
 67	return spi_read(spi, ts_data->rd_buf, sizeof(ts_data->rd_buf));
 68}
 69
 70static void surface3_spi_report_touch(struct surface3_ts_data *ts_data,
 71				   struct surface3_ts_data_finger *finger)
 72{
 73	int st = finger->status & 0x01;
 74	int slot;
 75
 76	slot = input_mt_get_slot_by_key(ts_data->input_dev,
 77				get_unaligned_le16(&finger->tracking_id));
 78	if (slot < 0)
 79		return;
 80
 81	input_mt_slot(ts_data->input_dev, slot);
 82	input_mt_report_slot_state(ts_data->input_dev, MT_TOOL_FINGER, st);
 83	if (st) {
 84		input_report_abs(ts_data->input_dev,
 85				 ABS_MT_POSITION_X,
 86				 get_unaligned_le16(&finger->x));
 87		input_report_abs(ts_data->input_dev,
 88				 ABS_MT_POSITION_Y,
 89				 get_unaligned_le16(&finger->y));
 90		input_report_abs(ts_data->input_dev,
 91				 ABS_MT_WIDTH_MAJOR,
 92				 get_unaligned_le16(&finger->width));
 93		input_report_abs(ts_data->input_dev,
 94				 ABS_MT_WIDTH_MINOR,
 95				 get_unaligned_le16(&finger->height));
 96	}
 97}
 98
 99static void surface3_spi_process_touch(struct surface3_ts_data *ts_data, u8 *data)
100{
101	u16 timestamp;
102	unsigned int i;
103	timestamp = get_unaligned_le16(&data[15]);
104
105	for (i = 0; i < 13; i++) {
106		struct surface3_ts_data_finger *finger;
107
108		finger = (struct surface3_ts_data_finger *)&data[17 +
109				i * sizeof(struct surface3_ts_data_finger)];
110
111		/*
112		 * When bit 5 of status is 1, it marks the end of the report:
113		 * - touch present: 0xe7
114		 * - touch released: 0xe4
115		 * - nothing valuable: 0xff
116		 */
117		if (finger->status & 0x10)
118			break;
119
120		surface3_spi_report_touch(ts_data, finger);
121	}
122
123	input_mt_sync_frame(ts_data->input_dev);
124	input_sync(ts_data->input_dev);
125}
126
127static void surface3_spi_report_pen(struct surface3_ts_data *ts_data,
128				    struct surface3_ts_data_pen *pen)
129{
130	struct input_dev *dev = ts_data->pen_input_dev;
131	int st = pen->status;
132	int prox = st & 0x01;
133	int rubber = st & 0x18;
134	int tool = (prox && rubber) ? BTN_TOOL_RUBBER : BTN_TOOL_PEN;
135
136	/* fake proximity out to switch tools */
137	if (ts_data->pen_tool != tool) {
138		input_report_key(dev, ts_data->pen_tool, 0);
139		input_sync(dev);
140		ts_data->pen_tool = tool;
141	}
142
143	input_report_key(dev, BTN_TOUCH, st & 0x12);
144
145	input_report_key(dev, ts_data->pen_tool, prox);
146
147	if (st) {
148		input_report_key(dev,
149				 BTN_STYLUS,
150				 st & 0x04);
151
152		input_report_abs(dev,
153				 ABS_X,
154				 get_unaligned_le16(&pen->x));
155		input_report_abs(dev,
156				 ABS_Y,
157				 get_unaligned_le16(&pen->y));
158		input_report_abs(dev,
159				 ABS_PRESSURE,
160				 get_unaligned_le16(&pen->pressure));
161	}
162}
163
164static void surface3_spi_process_pen(struct surface3_ts_data *ts_data, u8 *data)
165{
166	struct surface3_ts_data_pen *pen;
167
168	pen = (struct surface3_ts_data_pen *)&data[15];
169
170	surface3_spi_report_pen(ts_data, pen);
171	input_sync(ts_data->pen_input_dev);
172}
173
174static void surface3_spi_process(struct surface3_ts_data *ts_data)
175{
176	static const char header[] = {
177		0xff, 0xff, 0xff, 0xff, 0xa5, 0x5a, 0xe7, 0x7e, 0x01
178	};
179	u8 *data = ts_data->rd_buf;
180
181	if (memcmp(header, data, sizeof(header)))
182		dev_err(&ts_data->spi->dev,
183			"%s header error: %*ph, ignoring...\n",
184			__func__, (int)sizeof(header), data);
185
186	switch (data[9]) {
187	case SURFACE3_REPORT_TOUCH:
188		surface3_spi_process_touch(ts_data, data);
189		break;
190	case SURFACE3_REPORT_PEN:
191		surface3_spi_process_pen(ts_data, data);
192		break;
193	default:
194		dev_err(&ts_data->spi->dev,
195			"%s unknown packet type: %x, ignoring...\n",
196			__func__, data[9]);
197		break;
198	}
199}
200
201static irqreturn_t surface3_spi_irq_handler(int irq, void *dev_id)
202{
203	struct surface3_ts_data *data = dev_id;
204
205	if (surface3_spi_read(data))
206		return IRQ_HANDLED;
207
208	dev_dbg(&data->spi->dev, "%s received -> %*ph\n",
209		__func__, SURFACE3_PACKET_SIZE, data->rd_buf);
210	surface3_spi_process(data);
211
212	return IRQ_HANDLED;
213}
214
215static void surface3_spi_power(struct surface3_ts_data *data, bool on)
216{
217	gpiod_set_value(data->gpiod_rst[0], on);
218	gpiod_set_value(data->gpiod_rst[1], on);
219	/* let the device settle a little */
220	msleep(20);
221}
222
223/**
224 * surface3_spi_get_gpio_config - Get GPIO config from ACPI/DT
225 *
226 * @ts: surface3_spi_ts_data pointer
227 */
228static int surface3_spi_get_gpio_config(struct surface3_ts_data *data)
229{
230	int error;
231	struct device *dev;
232	struct gpio_desc *gpiod;
233	int i;
234
235	dev = &data->spi->dev;
236
237	/* Get the reset lines GPIO pin number */
238	for (i = 0; i < 2; i++) {
239		gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_OUT_LOW);
240		if (IS_ERR(gpiod)) {
241			error = PTR_ERR(gpiod);
242			if (error != -EPROBE_DEFER)
243				dev_err(dev,
244					"Failed to get power GPIO %d: %d\n",
245					i,
246					error);
247			return error;
248		}
249
250		data->gpiod_rst[i] = gpiod;
251	}
252
253	return 0;
254}
255
256static int surface3_spi_create_touch_input(struct surface3_ts_data *data)
257{
258	struct input_dev *input;
259	int error;
260
261	input = devm_input_allocate_device(&data->spi->dev);
262	if (!input)
263		return -ENOMEM;
264
265	data->input_dev = input;
266
267	input_set_abs_params(input, ABS_MT_POSITION_X, 0, 9600, 0, 0);
268	input_abs_set_res(input, ABS_MT_POSITION_X, 40);
269	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 7200, 0, 0);
270	input_abs_set_res(input, ABS_MT_POSITION_Y, 48);
271	input_set_abs_params(input, ABS_MT_WIDTH_MAJOR, 0, 1024, 0, 0);
272	input_set_abs_params(input, ABS_MT_WIDTH_MINOR, 0, 1024, 0, 0);
273	input_mt_init_slots(input, 10, INPUT_MT_DIRECT);
274
275	input->name = "Surface3 SPI Capacitive TouchScreen";
276	input->phys = "input/ts";
277	input->id.bustype = BUS_SPI;
278	input->id.vendor = 0x045e;	/* Microsoft */
279	input->id.product = 0x0001;
280	input->id.version = 0x0000;
281
282	error = input_register_device(input);
283	if (error) {
284		dev_err(&data->spi->dev,
285			"Failed to register input device: %d", error);
286		return error;
287	}
288
289	return 0;
290}
291
292static int surface3_spi_create_pen_input(struct surface3_ts_data *data)
293{
294	struct input_dev *input;
295	int error;
296
297	input = devm_input_allocate_device(&data->spi->dev);
298	if (!input)
299		return -ENOMEM;
300
301	data->pen_input_dev = input;
302	data->pen_tool = BTN_TOOL_PEN;
303
304	__set_bit(INPUT_PROP_DIRECT, input->propbit);
305	__set_bit(INPUT_PROP_POINTER, input->propbit);
306	input_set_abs_params(input, ABS_X, 0, 9600, 0, 0);
307	input_abs_set_res(input, ABS_X, 40);
308	input_set_abs_params(input, ABS_Y, 0, 7200, 0, 0);
309	input_abs_set_res(input, ABS_Y, 48);
310	input_set_abs_params(input, ABS_PRESSURE, 0, 1024, 0, 0);
311	input_set_capability(input, EV_KEY, BTN_TOUCH);
312	input_set_capability(input, EV_KEY, BTN_STYLUS);
313	input_set_capability(input, EV_KEY, BTN_TOOL_PEN);
314	input_set_capability(input, EV_KEY, BTN_TOOL_RUBBER);
315
316	input->name = "Surface3 SPI Pen Input";
317	input->phys = "input/ts";
318	input->id.bustype = BUS_SPI;
319	input->id.vendor = 0x045e;     /* Microsoft */
320	input->id.product = 0x0002;
321	input->id.version = 0x0000;
322
323	error = input_register_device(input);
324	if (error) {
325		dev_err(&data->spi->dev,
326			"Failed to register input device: %d", error);
327		return error;
328	}
329
330	return 0;
331}
332
333static int surface3_spi_probe(struct spi_device *spi)
334{
335	struct surface3_ts_data *data;
336	int error;
337
338	/* Set up SPI*/
339	spi->bits_per_word = 8;
340	spi->mode = SPI_MODE_0;
341	error = spi_setup(spi);
342	if (error)
343		return error;
344
345	data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
346	if (!data)
347		return -ENOMEM;
348
349	data->spi = spi;
350	spi_set_drvdata(spi, data);
351
352	error = surface3_spi_get_gpio_config(data);
353	if (error)
354		return error;
355
356	surface3_spi_power(data, true);
357	surface3_spi_power(data, false);
358	surface3_spi_power(data, true);
359
360	error = surface3_spi_create_touch_input(data);
361	if (error)
362		return error;
363
364	error = surface3_spi_create_pen_input(data);
365	if (error)
366		return error;
367
368	error = devm_request_threaded_irq(&spi->dev, spi->irq,
369					  NULL, surface3_spi_irq_handler,
370					  IRQF_ONESHOT,
371					  "Surface3-irq", data);
372	if (error)
373		return error;
374
375	return 0;
376}
377
378static int __maybe_unused surface3_spi_suspend(struct device *dev)
379{
380	struct spi_device *spi = to_spi_device(dev);
381	struct surface3_ts_data *data = spi_get_drvdata(spi);
382
383	disable_irq(data->spi->irq);
384
385	surface3_spi_power(data, false);
386
387	return 0;
388}
389
390static int __maybe_unused surface3_spi_resume(struct device *dev)
391{
392	struct spi_device *spi = to_spi_device(dev);
393	struct surface3_ts_data *data = spi_get_drvdata(spi);
394
395	surface3_spi_power(data, true);
396
397	enable_irq(data->spi->irq);
398
399	return 0;
400}
401
402static SIMPLE_DEV_PM_OPS(surface3_spi_pm_ops,
403			 surface3_spi_suspend,
404			 surface3_spi_resume);
405
406#ifdef CONFIG_ACPI
407static const struct acpi_device_id surface3_spi_acpi_match[] = {
408	{ "MSHW0037", 0 },
409	{ }
410};
411MODULE_DEVICE_TABLE(acpi, surface3_spi_acpi_match);
412#endif
413
414static struct spi_driver surface3_spi_driver = {
415	.driver = {
416		.name	= "Surface3-spi",
417		.acpi_match_table = ACPI_PTR(surface3_spi_acpi_match),
418		.pm = &surface3_spi_pm_ops,
419	},
420	.probe = surface3_spi_probe,
421};
422
423module_spi_driver(surface3_spi_driver);
424
425MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
426MODULE_DESCRIPTION("Surface 3 SPI touchscreen driver");
427MODULE_LICENSE("GPL v2");