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 <nsaenzjulienne@suse.de>
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 device_node *fw_node;
126	struct rpi_firmware *fw;
127	struct rpi_ts *ts;
128	u32 touchbuf;
129	int error;
130
131	fw_node = of_get_parent(np);
132	if (!fw_node) {
133		dev_err(dev, "Missing firmware node\n");
134		return -ENOENT;
135	}
136
137	fw = devm_rpi_firmware_get(&pdev->dev, fw_node);
138	of_node_put(fw_node);
139	if (!fw)
140		return -EPROBE_DEFER;
141
142	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
143	if (!ts)
144		return -ENOMEM;
145	ts->pdev = pdev;
146
147	ts->fw_regs_va = dma_alloc_coherent(dev, PAGE_SIZE, &ts->fw_regs_phys,
148					    GFP_KERNEL);
149	if (!ts->fw_regs_va) {
150		dev_err(dev, "failed to dma_alloc_coherent\n");
151		return -ENOMEM;
152	}
153
154	error = devm_add_action_or_reset(dev, rpi_ts_dma_cleanup, ts);
155	if (error) {
156		dev_err(dev, "failed to devm_add_action_or_reset, %d\n", error);
157		return error;
158	}
159
160	touchbuf = (u32)ts->fw_regs_phys;
161	error = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF,
162				      &touchbuf, sizeof(touchbuf));
163	if (error || touchbuf != 0) {
164		dev_warn(dev, "Failed to set touchbuf, %d\n", error);
165		return error;
166	}
167
168	input = devm_input_allocate_device(dev);
169	if (!input) {
170		dev_err(dev, "Failed to allocate input device\n");
171		return -ENOMEM;
172	}
173
174	ts->input = input;
175	input_set_drvdata(input, ts);
176
177	input->name = "raspberrypi-ts";
178	input->id.bustype = BUS_HOST;
179
180	input_set_abs_params(input, ABS_MT_POSITION_X, 0,
181			     RPI_TS_DEFAULT_WIDTH, 0, 0);
182	input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
183			     RPI_TS_DEFAULT_HEIGHT, 0, 0);
184	touchscreen_parse_properties(input, true, &ts->prop);
185
186	error = input_mt_init_slots(input, RPI_TS_MAX_SUPPORTED_POINTS,
187				    INPUT_MT_DIRECT);
188	if (error) {
189		dev_err(dev, "could not init mt slots, %d\n", error);
190		return error;
191	}
192
193	error = input_setup_polling(input, rpi_ts_poll);
194	if (error) {
195		dev_err(dev, "could not set up polling mode, %d\n", error);
196		return error;
197	}
198
199	input_set_poll_interval(input, RPI_TS_POLL_INTERVAL);
200
201	error = input_register_device(input);
202	if (error) {
203		dev_err(dev, "could not register input device, %d\n", error);
204		return error;
205	}
206
207	return 0;
208}
209
210static const struct of_device_id rpi_ts_match[] = {
211	{ .compatible = "raspberrypi,firmware-ts", },
212	{},
213};
214MODULE_DEVICE_TABLE(of, rpi_ts_match);
215
216static struct platform_driver rpi_ts_driver = {
217	.driver = {
218		.name = "raspberrypi-ts",
219		.of_match_table = rpi_ts_match,
220	},
221	.probe = rpi_ts_probe,
222};
223module_platform_driver(rpi_ts_driver);
224
225MODULE_AUTHOR("Gordon Hollingworth");
226MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
227MODULE_DESCRIPTION("Raspberry Pi firmware based touchscreen driver");
228MODULE_LICENSE("GPL v2");
229