1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Focaltech TouchPad PS/2 mouse driver
4 *
5 * Copyright (c) 2014 Red Hat Inc.
6 * Copyright (c) 2014 Mathias Gottschlag <mgottschlag@gmail.com>
7 *
8 * Red Hat authors:
9 *
10 * Hans de Goede <hdegoede@redhat.com>
11 */
12
13
14#include <linux/device.h>
15#include <linux/libps2.h>
16#include <linux/input/mt.h>
17#include <linux/serio.h>
18#include <linux/slab.h>
19#include "psmouse.h"
20#include "focaltech.h"
21
22static const char * const focaltech_pnp_ids[] = {
23	"FLT0101",
24	"FLT0102",
25	"FLT0103",
26	NULL
27};
28
29/*
30 * Even if the kernel is built without support for Focaltech PS/2 touchpads (or
31 * when the real driver fails to recognize the device), we still have to detect
32 * them in order to avoid further detection attempts confusing the touchpad.
33 * This way it at least works in PS/2 mouse compatibility mode.
34 */
35int focaltech_detect(struct psmouse *psmouse, bool set_properties)
36{
37	if (!psmouse_matches_pnp_id(psmouse, focaltech_pnp_ids))
38		return -ENODEV;
39
40	if (set_properties) {
41		psmouse->vendor = "FocalTech";
42		psmouse->name = "Touchpad";
43	}
44
45	return 0;
46}
47
48#ifdef CONFIG_MOUSE_PS2_FOCALTECH
49
50/*
51 * Packet types - the numbers are not consecutive, so we might be missing
52 * something here.
53 */
54#define FOC_TOUCH 0x3 /* bitmap of active fingers */
55#define FOC_ABS 0x6 /* absolute position of one finger */
56#define FOC_REL 0x9 /* relative position of 1-2 fingers */
57
58#define FOC_MAX_FINGERS 5
59
60/*
61 * Current state of a single finger on the touchpad.
62 */
63struct focaltech_finger_state {
64	/* The touchpad has generated a touch event for the finger */
65	bool active;
66
67	/*
68	 * The touchpad has sent position data for the finger. The
69	 * flag is 0 when the finger is not active, and there is a
70	 * time between the first touch event for the finger and the
71	 * following absolute position packet for the finger where the
72	 * touchpad has declared the finger to be valid, but we do not
73	 * have any valid position yet.
74	 */
75	bool valid;
76
77	/*
78	 * Absolute position (from the bottom left corner) of the
79	 * finger.
80	 */
81	unsigned int x;
82	unsigned int y;
83};
84
85/*
86 * Description of the current state of the touchpad hardware.
87 */
88struct focaltech_hw_state {
89	/*
90	 * The touchpad tracks the positions of the fingers for us,
91	 * the array indices correspond to the finger indices returned
92	 * in the report packages.
93	 */
94	struct focaltech_finger_state fingers[FOC_MAX_FINGERS];
95
96	/*
97	 * Finger width 0-7 and 15 for a very big contact area.
98	 * 15 value stays until the finger is released.
99	 * Width is reported only in absolute packets.
100	 * Since hardware reports width only for last touching finger,
101	 * there is no need to store width for every specific finger,
102	 * so we keep only last value reported.
103	 */
104	unsigned int width;
105
106	/* True if the clickpad has been pressed. */
107	bool pressed;
108};
109
110struct focaltech_data {
111	unsigned int x_max, y_max;
112	struct focaltech_hw_state state;
113};
114
115static void focaltech_report_state(struct psmouse *psmouse)
116{
117	struct focaltech_data *priv = psmouse->private;
118	struct focaltech_hw_state *state = &priv->state;
119	struct input_dev *dev = psmouse->dev;
120	int i;
121
122	for (i = 0; i < FOC_MAX_FINGERS; i++) {
123		struct focaltech_finger_state *finger = &state->fingers[i];
124		bool active = finger->active && finger->valid;
125
126		input_mt_slot(dev, i);
127		input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
128		if (active) {
129			unsigned int clamped_x, clamped_y;
130			/*
131			 * The touchpad might report invalid data, so we clamp
132			 * the resulting values so that we do not confuse
133			 * userspace.
134			 */
135			clamped_x = clamp(finger->x, 0U, priv->x_max);
136			clamped_y = clamp(finger->y, 0U, priv->y_max);
137			input_report_abs(dev, ABS_MT_POSITION_X, clamped_x);
138			input_report_abs(dev, ABS_MT_POSITION_Y,
139					 priv->y_max - clamped_y);
140			input_report_abs(dev, ABS_TOOL_WIDTH, state->width);
141		}
142	}
143	input_mt_report_pointer_emulation(dev, true);
144
145	input_report_key(dev, BTN_LEFT, state->pressed);
146	input_sync(dev);
147}
148
149static void focaltech_process_touch_packet(struct psmouse *psmouse,
150					   unsigned char *packet)
151{
152	struct focaltech_data *priv = psmouse->private;
153	struct focaltech_hw_state *state = &priv->state;
154	unsigned char fingers = packet[1];
155	int i;
156
157	state->pressed = (packet[0] >> 4) & 1;
158
159	/* the second byte contains a bitmap of all fingers touching the pad */
160	for (i = 0; i < FOC_MAX_FINGERS; i++) {
161		state->fingers[i].active = fingers & 0x1;
162		if (!state->fingers[i].active) {
163			/*
164			 * Even when the finger becomes active again, we still
165			 * will have to wait for the first valid position.
166			 */
167			state->fingers[i].valid = false;
168		}
169		fingers >>= 1;
170	}
171}
172
173static void focaltech_process_abs_packet(struct psmouse *psmouse,
174					 unsigned char *packet)
175{
176	struct focaltech_data *priv = psmouse->private;
177	struct focaltech_hw_state *state = &priv->state;
178	unsigned int finger;
179
180	finger = (packet[1] >> 4) - 1;
181	if (finger >= FOC_MAX_FINGERS) {
182		psmouse_err(psmouse, "Invalid finger in abs packet: %d\n",
183			    finger);
184		return;
185	}
186
187	state->pressed = (packet[0] >> 4) & 1;
188
189	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
190	state->fingers[finger].y = (packet[3] << 8) | packet[4];
191	state->width = packet[5] >> 4;
192	state->fingers[finger].valid = true;
193}
194
195static void focaltech_process_rel_packet(struct psmouse *psmouse,
196					 unsigned char *packet)
197{
198	struct focaltech_data *priv = psmouse->private;
199	struct focaltech_hw_state *state = &priv->state;
200	int finger1, finger2;
201
202	state->pressed = packet[0] >> 7;
203	finger1 = ((packet[0] >> 4) & 0x7) - 1;
204	if (finger1 < FOC_MAX_FINGERS) {
205		state->fingers[finger1].x += (s8)packet[1];
206		state->fingers[finger1].y += (s8)packet[2];
207	} else {
208		psmouse_err(psmouse, "First finger in rel packet invalid: %d\n",
209			    finger1);
210	}
211
212	/*
213	 * If there is an odd number of fingers, the last relative
214	 * packet only contains one finger. In this case, the second
215	 * finger index in the packet is 0 (we subtract 1 in the lines
216	 * above to create array indices, so the finger will overflow
217	 * and be above FOC_MAX_FINGERS).
218	 */
219	finger2 = ((packet[3] >> 4) & 0x7) - 1;
220	if (finger2 < FOC_MAX_FINGERS) {
221		state->fingers[finger2].x += (s8)packet[4];
222		state->fingers[finger2].y += (s8)packet[5];
223	}
224}
225
226static void focaltech_process_packet(struct psmouse *psmouse)
227{
228	unsigned char *packet = psmouse->packet;
229
230	switch (packet[0] & 0xf) {
231	case FOC_TOUCH:
232		focaltech_process_touch_packet(psmouse, packet);
233		break;
234
235	case FOC_ABS:
236		focaltech_process_abs_packet(psmouse, packet);
237		break;
238
239	case FOC_REL:
240		focaltech_process_rel_packet(psmouse, packet);
241		break;
242
243	default:
244		psmouse_err(psmouse, "Unknown packet type: %02x\n", packet[0]);
245		break;
246	}
247
248	focaltech_report_state(psmouse);
249}
250
251static psmouse_ret_t focaltech_process_byte(struct psmouse *psmouse)
252{
253	if (psmouse->pktcnt >= 6) { /* Full packet received */
254		focaltech_process_packet(psmouse);
255		return PSMOUSE_FULL_PACKET;
256	}
257
258	/*
259	 * We might want to do some validation of the data here, but
260	 * we do not know the protocol well enough
261	 */
262	return PSMOUSE_GOOD_DATA;
263}
264
265static int focaltech_switch_protocol(struct psmouse *psmouse)
266{
267	struct ps2dev *ps2dev = &psmouse->ps2dev;
268	unsigned char param[3];
269
270	param[0] = 0;
271	if (ps2_command(ps2dev, param, 0x10f8))
272		return -EIO;
273
274	if (ps2_command(ps2dev, param, 0x10f8))
275		return -EIO;
276
277	if (ps2_command(ps2dev, param, 0x10f8))
278		return -EIO;
279
280	param[0] = 1;
281	if (ps2_command(ps2dev, param, 0x10f8))
282		return -EIO;
283
284	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
285		return -EIO;
286
287	if (ps2_command(ps2dev, param, PSMOUSE_CMD_ENABLE))
288		return -EIO;
289
290	return 0;
291}
292
293static void focaltech_reset(struct psmouse *psmouse)
294{
295	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
296	psmouse_reset(psmouse);
297}
298
299static void focaltech_disconnect(struct psmouse *psmouse)
300{
301	focaltech_reset(psmouse);
302	kfree(psmouse->private);
303	psmouse->private = NULL;
304}
305
306static int focaltech_reconnect(struct psmouse *psmouse)
307{
308	int error;
309
310	focaltech_reset(psmouse);
311
312	error = focaltech_switch_protocol(psmouse);
313	if (error) {
314		psmouse_err(psmouse, "Unable to initialize the device\n");
315		return error;
316	}
317
318	return 0;
319}
320
321static void focaltech_set_input_params(struct psmouse *psmouse)
322{
323	struct input_dev *dev = psmouse->dev;
324	struct focaltech_data *priv = psmouse->private;
325
326	/*
327	 * Undo part of setup done for us by psmouse core since touchpad
328	 * is not a relative device.
329	 */
330	__clear_bit(EV_REL, dev->evbit);
331	__clear_bit(REL_X, dev->relbit);
332	__clear_bit(REL_Y, dev->relbit);
333	__clear_bit(BTN_RIGHT, dev->keybit);
334	__clear_bit(BTN_MIDDLE, dev->keybit);
335
336	/*
337	 * Now set up our capabilities.
338	 */
339	__set_bit(EV_ABS, dev->evbit);
340	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
341	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
342	input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0);
343	input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
344	__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
345}
346
347static int focaltech_read_register(struct ps2dev *ps2dev, int reg,
348				   unsigned char *param)
349{
350	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
351		return -EIO;
352
353	param[0] = 0;
354	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
355		return -EIO;
356
357	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
358		return -EIO;
359
360	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
361		return -EIO;
362
363	param[0] = reg;
364	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
365		return -EIO;
366
367	if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
368		return -EIO;
369
370	return 0;
371}
372
373static int focaltech_read_size(struct psmouse *psmouse)
374{
375	struct ps2dev *ps2dev = &psmouse->ps2dev;
376	struct focaltech_data *priv = psmouse->private;
377	char param[3];
378
379	if (focaltech_read_register(ps2dev, 2, param))
380		return -EIO;
381
382	/* not sure whether this is 100% correct */
383	priv->x_max = (unsigned char)param[1] * 128;
384	priv->y_max = (unsigned char)param[2] * 128;
385
386	return 0;
387}
388
389static void focaltech_set_resolution(struct psmouse *psmouse,
390				     unsigned int resolution)
391{
392	/* not supported yet */
393}
394
395static void focaltech_set_rate(struct psmouse *psmouse, unsigned int rate)
396{
397	/* not supported yet */
398}
399
400static void focaltech_set_scale(struct psmouse *psmouse,
401				enum psmouse_scale scale)
402{
403	/* not supported yet */
404}
405
406int focaltech_init(struct psmouse *psmouse)
407{
408	struct focaltech_data *priv;
409	int error;
410
411	psmouse->private = priv = kzalloc(sizeof(struct focaltech_data),
412					  GFP_KERNEL);
413	if (!priv)
414		return -ENOMEM;
415
416	focaltech_reset(psmouse);
417
418	error = focaltech_read_size(psmouse);
419	if (error) {
420		psmouse_err(psmouse,
421			    "Unable to read the size of the touchpad\n");
422		goto fail;
423	}
424
425	error = focaltech_switch_protocol(psmouse);
426	if (error) {
427		psmouse_err(psmouse, "Unable to initialize the device\n");
428		goto fail;
429	}
430
431	focaltech_set_input_params(psmouse);
432
433	psmouse->protocol_handler = focaltech_process_byte;
434	psmouse->pktsize = 6;
435	psmouse->disconnect = focaltech_disconnect;
436	psmouse->reconnect = focaltech_reconnect;
437	psmouse->cleanup = focaltech_reset;
438	/* resync is not supported yet */
439	psmouse->resync_time = 0;
440	/*
441	 * rate/resolution/scale changes are not supported yet, and
442	 * the generic implementations of these functions seem to
443	 * confuse some touchpads
444	 */
445	psmouse->set_resolution = focaltech_set_resolution;
446	psmouse->set_rate = focaltech_set_rate;
447	psmouse->set_scale = focaltech_set_scale;
448
449	return 0;
450
451fail:
452	focaltech_reset(psmouse);
453	kfree(priv);
454	return error;
455}
456#endif /* CONFIG_MOUSE_PS2_FOCALTECH */
457