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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Raspberry Pi firmware based touchscreen driver
4 *
5 * Copyright (C) 2015, 2017 Raspberry Pi
6 * Copyright (C) 2018 Nicolas Saenz Julienne <[email protected]>
7 */
8
9#include <linux/io.h>
10#include <linux/of.h>
11#include <linux/slab.h>
12#include <linux/device.h>
13#include <linux/module.h>
14#include <linux/bitops.h>
15#include <linux/dma-mapping.h>
16#include <linux/platform_device.h>
17#include <linux/input.h>
18#include <linux/input/mt.h>
19#include <linux/input/touchscreen.h>
20#include <soc/bcm2835/raspberrypi-firmware.h>
21
22#define RPI_TS_DEFAULT_WIDTH 800
23#define RPI_TS_DEFAULT_HEIGHT 480
24
25#define RPI_TS_MAX_SUPPORTED_POINTS 10
26
27#define RPI_TS_FTS_TOUCH_DOWN 0
28#define RPI_TS_FTS_TOUCH_CONTACT 2
29
30#define RPI_TS_POLL_INTERVAL 17 /* 60fps */
31
32#define RPI_TS_NPOINTS_REG_INVALIDATE 99
33
34struct rpi_ts {
35 struct platform_device *pdev;
36 struct input_dev *input;
37 struct touchscreen_properties prop;
38
39 void __iomem *fw_regs_va;
40 dma_addr_t fw_regs_phys;
41
42 int known_ids;
43};
44
45struct rpi_ts_regs {
46 u8 device_mode;
47 u8 gesture_id;
48 u8 num_points;
49 struct rpi_ts_touch {
50 u8 xh;
51 u8 xl;
52 u8 yh;
53 u8 yl;
54 u8 pressure; /* Not supported */
55 u8 area; /* Not supported */
56 } point[RPI_TS_MAX_SUPPORTED_POINTS];
57};
58
59static void rpi_ts_poll(struct input_dev *input)
60{
61 struct rpi_ts *ts = input_get_drvdata(input);
62 struct rpi_ts_regs regs;
63 int modified_ids = 0;
64 long released_ids;
65 int event_type;
66 int touchid;
67 int x, y;
68 int i;
69
70 memcpy_fromio(&regs, ts->fw_regs_va, sizeof(regs));
71 /*
72 * We poll the memory based register copy of the touchscreen chip using
73 * the number of points register to know whether the copy has been
74 * updated (we write 99 to the memory copy, the GPU will write between
75 * 0 - 10 points)
76 */
77 iowrite8(RPI_TS_NPOINTS_REG_INVALIDATE,
78 ts->fw_regs_va + offsetof(struct rpi_ts_regs, num_points));
79
80 if (regs.num_points == RPI_TS_NPOINTS_REG_INVALIDATE ||
81 (regs.num_points == 0 && ts->known_ids == 0))
82 return;
83
84 for (i = 0; i < regs.num_points; i++) {
85 x = (((int)regs.point[i].xh & 0xf) << 8) + regs.point[i].xl;
86 y = (((int)regs.point[i].yh & 0xf) << 8) + regs.point[i].yl;
87 touchid = (regs.point[i].yh >> 4) & 0xf;
88 event_type = (regs.point[i].xh >> 6) & 0x03;
89
90 modified_ids |= BIT(touchid);
91
92 if (event_type == RPI_TS_FTS_TOUCH_DOWN ||
93 event_type == RPI_TS_FTS_TOUCH_CONTACT) {
94 input_mt_slot(input, touchid);
95 input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
96 touchscreen_report_pos(input, &ts->prop, x, y, true);
97 }
98 }
99
100 released_ids = ts->known_ids & ~modified_ids;
101 for_each_set_bit(i, &released_ids, RPI_TS_MAX_SUPPORTED_POINTS) {
102 input_mt_slot(input, i);
103 input_mt_report_slot_inactive(input);
104 modified_ids &= ~(BIT(i));
105 }
106 ts->known_ids = modified_ids;
107
108 input_mt_sync_frame(input);
109 input_sync(input);
110}
111
112static void rpi_ts_dma_cleanup(void *data)
113{
114 struct rpi_ts *ts = data;
115 struct device *dev = &ts->pdev->dev;
116
117 dma_free_coherent(dev, PAGE_SIZE, ts->fw_regs_va, ts->fw_regs_phys);
118}
119
120static int rpi_ts_probe(struct platform_device *pdev)
121{
122 struct device *dev = &pdev->dev;
123 struct device_node *np = dev->of_node;
124 struct input_dev *input;
125 struct rpi_firmware *fw;
126 struct rpi_ts *ts;
127 u32 touchbuf;
128 int error;
129
130 struct device_node *fw_node __free(device_node) = of_get_parent(np);
131 if (!fw_node) {
132 dev_err(dev, "Missing firmware node\n");
133 return -ENOENT;
134 }
135
136 fw = devm_rpi_firmware_get(&pdev->dev, fw_node);
137 if (!fw)
138 return -EPROBE_DEFER;
139
140 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
141 if (!ts)
142 return -ENOMEM;
143 ts->pdev = pdev;
144
145 ts->fw_regs_va = dma_alloc_coherent(dev, PAGE_SIZE, &ts->fw_regs_phys,
146 GFP_KERNEL);
147 if (!ts->fw_regs_va) {
148 dev_err(dev, "failed to dma_alloc_coherent\n");
149 return -ENOMEM;
150 }
151
152 error = devm_add_action_or_reset(dev, rpi_ts_dma_cleanup, ts);
153 if (error) {
154 dev_err(dev, "failed to devm_add_action_or_reset, %d\n", error);
155 return error;
156 }
157
158 touchbuf = (u32)ts->fw_regs_phys;
159 error = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF,
160 &touchbuf, sizeof(touchbuf));
161 if (error || touchbuf != 0) {
162 dev_warn(dev, "Failed to set touchbuf, %d\n", error);
163 return error;
164 }
165
166 input = devm_input_allocate_device(dev);
167 if (!input) {
168 dev_err(dev, "Failed to allocate input device\n");
169 return -ENOMEM;
170 }
171
172 ts->input = input;
173 input_set_drvdata(input, ts);
174
175 input->name = "raspberrypi-ts";
176 input->id.bustype = BUS_HOST;
177
178 input_set_abs_params(input, ABS_MT_POSITION_X, 0,
179 RPI_TS_DEFAULT_WIDTH, 0, 0);
180 input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
181 RPI_TS_DEFAULT_HEIGHT, 0, 0);
182 touchscreen_parse_properties(input, true, &ts->prop);
183
184 error = input_mt_init_slots(input, RPI_TS_MAX_SUPPORTED_POINTS,
185 INPUT_MT_DIRECT);
186 if (error) {
187 dev_err(dev, "could not init mt slots, %d\n", error);
188 return error;
189 }
190
191 error = input_setup_polling(input, rpi_ts_poll);
192 if (error) {
193 dev_err(dev, "could not set up polling mode, %d\n", error);
194 return error;
195 }
196
197 input_set_poll_interval(input, RPI_TS_POLL_INTERVAL);
198
199 error = input_register_device(input);
200 if (error) {
201 dev_err(dev, "could not register input device, %d\n", error);
202 return error;
203 }
204
205 return 0;
206}
207
208static const struct of_device_id rpi_ts_match[] = {
209 { .compatible = "raspberrypi,firmware-ts", },
210 {},
211};
212MODULE_DEVICE_TABLE(of, rpi_ts_match);
213
214static struct platform_driver rpi_ts_driver = {
215 .driver = {
216 .name = "raspberrypi-ts",
217 .of_match_table = rpi_ts_match,
218 },
219 .probe = rpi_ts_probe,
220};
221module_platform_driver(rpi_ts_driver);
222
223MODULE_AUTHOR("Gordon Hollingworth");
224MODULE_AUTHOR("Nicolas Saenz Julienne <[email protected]>");
225MODULE_DESCRIPTION("Raspberry Pi firmware based touchscreen driver");
226MODULE_LICENSE("GPL v2");