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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * HID driver for UC-Logic devices not fully compliant with HID standard
4 * - tablet initialization and parameter retrieval
5 *
6 * Copyright (c) 2018 Nikolai Kondrashov
7 */
8
9/*
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 */
15
16#ifndef _HID_UCLOGIC_PARAMS_H
17#define _HID_UCLOGIC_PARAMS_H
18
19#include <linux/usb.h>
20#include <linux/hid.h>
21
22/* Types of pen in-range reporting */
23enum uclogic_params_pen_inrange {
24 /* Normal reports: zero - out of proximity, one - in proximity */
25 UCLOGIC_PARAMS_PEN_INRANGE_NORMAL = 0,
26 /* Inverted reports: zero - in proximity, one - out of proximity */
27 UCLOGIC_PARAMS_PEN_INRANGE_INVERTED,
28 /* No reports */
29 UCLOGIC_PARAMS_PEN_INRANGE_NONE,
30};
31
32/*
33 * Pen report's subreport data.
34 */
35struct uclogic_params_pen_subreport {
36 /*
37 * The value of the second byte of the pen report indicating this
38 * subreport. If zero, the subreport should be considered invalid and
39 * not matched.
40 */
41 __u8 value;
42
43 /*
44 * The ID to be assigned to the report, if the second byte of the pen
45 * report is equal to "value". Only valid if "value" is not zero.
46 */
47 __u8 id;
48};
49
50/*
51 * Tablet interface's pen input parameters.
52 *
53 * Must use declarative (descriptive) language, not imperative, to simplify
54 * understanding and maintain consistency.
55 *
56 * Noop (preserving functionality) when filled with zeroes.
57 */
58struct uclogic_params_pen {
59 /*
60 * True if pen usage is invalid for this interface and should be
61 * ignored, false otherwise.
62 */
63 bool usage_invalid;
64 /*
65 * Pointer to report descriptor part describing the pen inputs.
66 * Allocated with kmalloc. NULL if the part is not specified.
67 */
68 __u8 *desc_ptr;
69 /*
70 * Size of the report descriptor.
71 * Only valid, if "desc_ptr" is not NULL.
72 */
73 unsigned int desc_size;
74 /* Report ID, if reports should be tweaked, zero if not */
75 unsigned int id;
76 /* The list of subreports, only valid if "id" is not zero */
77 struct uclogic_params_pen_subreport subreport_list[3];
78 /* Type of in-range reporting, only valid if "id" is not zero */
79 enum uclogic_params_pen_inrange inrange;
80 /*
81 * True, if reports include fragmented high resolution coords, with
82 * high-order X and then Y bytes following the pressure field.
83 * Only valid if "id" is not zero.
84 */
85 bool fragmented_hires;
86 /*
87 * True if the pen reports tilt in bytes at offset 10 (X) and 11 (Y),
88 * and the Y tilt direction is flipped.
89 * Only valid if "id" is not zero.
90 */
91 bool tilt_y_flipped;
92};
93
94/*
95 * Parameters of frame control inputs of a tablet interface.
96 *
97 * Must use declarative (descriptive) language, not imperative, to simplify
98 * understanding and maintain consistency.
99 *
100 * Noop (preserving functionality) when filled with zeroes.
101 */
102struct uclogic_params_frame {
103 /*
104 * Pointer to report descriptor part describing the frame inputs.
105 * Allocated with kmalloc. NULL if the part is not specified.
106 */
107 __u8 *desc_ptr;
108 /*
109 * Size of the report descriptor.
110 * Only valid, if "desc_ptr" is not NULL.
111 */
112 unsigned int desc_size;
113 /*
114 * Report ID, if reports should be tweaked, zero if not.
115 */
116 unsigned int id;
117 /*
118 * The suffix to add to the input device name, if not NULL.
119 */
120 const char *suffix;
121 /*
122 * Number of the least-significant bit of the 2-bit state of a rotary
123 * encoder, in the report. Cannot point to a 2-bit field crossing a
124 * byte boundary. Zero if not present. Only valid if "id" is not zero.
125 */
126 unsigned int re_lsb;
127 /*
128 * Offset of the Wacom-style device ID byte in the report, to be set
129 * to pad device ID (0xf), for compatibility with Wacom drivers. Zero
130 * if no changes to the report should be made. The ID byte will be set
131 * to zero whenever the byte pointed by "touch_byte" is zero, if
132 * the latter is valid. Only valid if "id" is not zero.
133 */
134 unsigned int dev_id_byte;
135 /*
136 * Offset of the touch ring/strip state byte, in the report.
137 * Zero if not present. If dev_id_byte is also valid and non-zero,
138 * then the device ID byte will be cleared when the byte pointed to by
139 * this offset is zero. Only valid if "id" is not zero.
140 */
141 unsigned int touch_byte;
142 /*
143 * The value to anchor the reversed touch ring/strip reports at.
144 * I.e. one, if the reports should be flipped without offset.
145 * Zero if no reversal should be done.
146 * Only valid if "touch_byte" is valid and not zero.
147 */
148 __s8 touch_flip_at;
149 /*
150 * Maximum value of the touch ring/strip report around which the value
151 * should be wrapped when flipping according to "touch_flip_at".
152 * The minimum valid value is considered to be one, with zero being
153 * out-of-proximity (finger lift) value.
154 * Only valid if "touch_flip_at" is valid and not zero.
155 */
156 __s8 touch_max;
157 /*
158 * Offset of the bitmap dial byte, in the report. Zero if not present.
159 * Only valid if "id" is not zero. A bitmap dial sends reports with a
160 * dedicated bit per direction: 1 means clockwise rotation, 2 means
161 * counterclockwise, as opposed to the normal 1 and -1.
162 */
163 unsigned int bitmap_dial_byte;
164};
165
166/*
167 * Tablet interface report parameters.
168 *
169 * Must use declarative (descriptive) language, not imperative, to simplify
170 * understanding and maintain consistency.
171 *
172 * When filled with zeros represents a "noop" configuration - passes all
173 * reports unchanged and lets the generic HID driver handle everything.
174 *
175 * The resulting device report descriptor is assembled from all the report
176 * descriptor parts referenced by the structure. No order of assembly should
177 * be assumed. The structure represents original device report descriptor if
178 * all the parts are NULL.
179 */
180struct uclogic_params {
181 /*
182 * True if the whole interface is invalid, false otherwise.
183 */
184 bool invalid;
185 /*
186 * Pointer to the common part of the replacement report descriptor,
187 * allocated with kmalloc. NULL if no common part is needed.
188 * Only valid, if "invalid" is false.
189 */
190 __u8 *desc_ptr;
191 /*
192 * Size of the common part of the replacement report descriptor.
193 * Only valid, if "desc_ptr" is valid and not NULL.
194 */
195 unsigned int desc_size;
196 /*
197 * Pen parameters and optional report descriptor part.
198 * Only valid, if "invalid" is false.
199 */
200 struct uclogic_params_pen pen;
201 /*
202 * The list of frame control parameters and optional report descriptor
203 * parts. Only valid, if "invalid" is false.
204 */
205 struct uclogic_params_frame frame_list[3];
206};
207
208/* Initialize a tablet interface and discover its parameters */
209extern int uclogic_params_init(struct uclogic_params *params,
210 struct hid_device *hdev);
211
212/* Get a replacement report descriptor for a tablet's interface. */
213extern int uclogic_params_get_desc(const struct uclogic_params *params,
214 __u8 **pdesc,
215 unsigned int *psize);
216
217/* Free resources used by tablet interface's parameters */
218extern void uclogic_params_cleanup(struct uclogic_params *params);
219
220/* Dump tablet interface parameters with hid_dbg() */
221extern void uclogic_params_hid_dbg(const struct hid_device *hdev,
222 const struct uclogic_params *params);
223
224#endif /* _HID_UCLOGIC_PARAMS_H */