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 
34 struct 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 
45 struct 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 
rpi_ts_poll(struct input_dev * input)59 static 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 
rpi_ts_dma_cleanup(void * data)112 static 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 
rpi_ts_probe(struct platform_device * pdev)120 static 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 
210 static const struct of_device_id rpi_ts_match[] = {
211 	{ .compatible = "raspberrypi,firmware-ts", },
212 	{},
213 };
214 MODULE_DEVICE_TABLE(of, rpi_ts_match);
215 
216 static 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 };
223 module_platform_driver(rpi_ts_driver);
224 
225 MODULE_AUTHOR("Gordon Hollingworth");
226 MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
227 MODULE_DESCRIPTION("Raspberry Pi firmware based touchscreen driver");
228 MODULE_LICENSE("GPL v2");
229