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-polldev.h>
 20#include <linux/input/touchscreen.h>
 21#include <soc/bcm2835/raspberrypi-firmware.h>
 22
 23#define RPI_TS_DEFAULT_WIDTH	800
 24#define RPI_TS_DEFAULT_HEIGHT	480
 25
 26#define RPI_TS_MAX_SUPPORTED_POINTS	10
 27
 28#define RPI_TS_FTS_TOUCH_DOWN		0
 29#define RPI_TS_FTS_TOUCH_CONTACT	2
 30
 31#define RPI_TS_POLL_INTERVAL		17	/* 60fps */
 32
 33#define RPI_TS_NPOINTS_REG_INVALIDATE	99
 34
 35struct rpi_ts {
 36	struct platform_device *pdev;
 37	struct input_polled_dev *poll_dev;
 38	struct touchscreen_properties prop;
 39
 40	void __iomem *fw_regs_va;
 41	dma_addr_t fw_regs_phys;
 42
 43	int known_ids;
 44};
 45
 46struct rpi_ts_regs {
 47	u8 device_mode;
 48	u8 gesture_id;
 49	u8 num_points;
 50	struct rpi_ts_touch {
 51		u8 xh;
 52		u8 xl;
 53		u8 yh;
 54		u8 yl;
 55		u8 pressure; /* Not supported */
 56		u8 area;     /* Not supported */
 57	} point[RPI_TS_MAX_SUPPORTED_POINTS];
 58};
 59
 60static void rpi_ts_poll(struct input_polled_dev *dev)
 61{
 62	struct input_dev *input = dev->input;
 63	struct rpi_ts *ts = dev->private;
 64	struct rpi_ts_regs regs;
 65	int modified_ids = 0;
 66	long released_ids;
 67	int event_type;
 68	int touchid;
 69	int x, y;
 70	int i;
 71
 72	memcpy_fromio(&regs, ts->fw_regs_va, sizeof(regs));
 73	/*
 74	 * We poll the memory based register copy of the touchscreen chip using
 75	 * the number of points register to know whether the copy has been
 76	 * updated (we write 99 to the memory copy, the GPU will write between
 77	 * 0 - 10 points)
 78	 */
 79	iowrite8(RPI_TS_NPOINTS_REG_INVALIDATE,
 80		 ts->fw_regs_va + offsetof(struct rpi_ts_regs, num_points));
 81
 82	if (regs.num_points == RPI_TS_NPOINTS_REG_INVALIDATE ||
 83	    (regs.num_points == 0 && ts->known_ids == 0))
 84		return;
 85
 86	for (i = 0; i < regs.num_points; i++) {
 87		x = (((int)regs.point[i].xh & 0xf) << 8) + regs.point[i].xl;
 88		y = (((int)regs.point[i].yh & 0xf) << 8) + regs.point[i].yl;
 89		touchid = (regs.point[i].yh >> 4) & 0xf;
 90		event_type = (regs.point[i].xh >> 6) & 0x03;
 91
 92		modified_ids |= BIT(touchid);
 93
 94		if (event_type == RPI_TS_FTS_TOUCH_DOWN ||
 95		    event_type == RPI_TS_FTS_TOUCH_CONTACT) {
 96			input_mt_slot(input, touchid);
 97			input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
 98			touchscreen_report_pos(input, &ts->prop, x, y, true);
 99		}
100	}
101
102	released_ids = ts->known_ids & ~modified_ids;
103	for_each_set_bit(i, &released_ids, RPI_TS_MAX_SUPPORTED_POINTS) {
104		input_mt_slot(input, i);
105		input_mt_report_slot_state(input, MT_TOOL_FINGER, 0);
106		modified_ids &= ~(BIT(i));
107	}
108	ts->known_ids = modified_ids;
109
110	input_mt_sync_frame(input);
111	input_sync(input);
112}
113
114static void rpi_ts_dma_cleanup(void *data)
115{
116	struct rpi_ts *ts = data;
117	struct device *dev = &ts->pdev->dev;
118
119	dma_free_coherent(dev, PAGE_SIZE, ts->fw_regs_va, ts->fw_regs_phys);
120}
121
122static int rpi_ts_probe(struct platform_device *pdev)
123{
124	struct device *dev = &pdev->dev;
125	struct device_node *np = dev->of_node;
126	struct input_polled_dev *poll_dev;
127	struct device_node *fw_node;
128	struct rpi_firmware *fw;
129	struct input_dev *input;
130	struct rpi_ts *ts;
131	u32 touchbuf;
132	int error;
133
134	fw_node = of_get_parent(np);
135	if (!fw_node) {
136		dev_err(dev, "Missing firmware node\n");
137		return -ENOENT;
138	}
139
140	fw = rpi_firmware_get(fw_node);
141	of_node_put(fw_node);
142	if (!fw)
143		return -EPROBE_DEFER;
144
145	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
146	if (!ts)
147		return -ENOMEM;
148	ts->pdev = pdev;
149
150	ts->fw_regs_va = dma_alloc_coherent(dev, PAGE_SIZE, &ts->fw_regs_phys,
151					    GFP_KERNEL);
152	if (!ts->fw_regs_va) {
153		dev_err(dev, "failed to dma_alloc_coherent\n");
154		return -ENOMEM;
155	}
156
157	error = devm_add_action_or_reset(dev, rpi_ts_dma_cleanup, ts);
158	if (error) {
159		dev_err(dev, "failed to devm_add_action_or_reset, %d\n", error);
160		return error;
161	}
162
163
164	touchbuf = (u32)ts->fw_regs_phys;
165	error = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF,
166				      &touchbuf, sizeof(touchbuf));
167
168	if (error || touchbuf != 0) {
169		dev_warn(dev, "Failed to set touchbuf, %d\n", error);
170		return error;
171	}
172
173	poll_dev = devm_input_allocate_polled_device(dev);
174	if (!poll_dev) {
175		dev_err(dev, "Failed to allocate input device\n");
176		return -ENOMEM;
177	}
178	ts->poll_dev = poll_dev;
179	input = poll_dev->input;
180
181	input->name = "raspberrypi-ts";
182	input->id.bustype = BUS_HOST;
183	poll_dev->poll_interval = RPI_TS_POLL_INTERVAL;
184	poll_dev->poll = rpi_ts_poll;
185	poll_dev->private = ts;
186
187	input_set_abs_params(input, ABS_MT_POSITION_X, 0,
188			     RPI_TS_DEFAULT_WIDTH, 0, 0);
189	input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
190			     RPI_TS_DEFAULT_HEIGHT, 0, 0);
191	touchscreen_parse_properties(input, true, &ts->prop);
192
193	error = input_mt_init_slots(input, RPI_TS_MAX_SUPPORTED_POINTS,
194				    INPUT_MT_DIRECT);
195	if (error) {
196		dev_err(dev, "could not init mt slots, %d\n", error);
197		return error;
198	}
199
200	error = input_register_polled_device(poll_dev);
201	if (error) {
202		dev_err(dev, "could not register input device, %d\n", error);
203		return error;
204	}
205
206	return 0;
207}
208
209static const struct of_device_id rpi_ts_match[] = {
210	{ .compatible = "raspberrypi,firmware-ts", },
211	{},
212};
213MODULE_DEVICE_TABLE(of, rpi_ts_match);
214
215static struct platform_driver rpi_ts_driver = {
216	.driver = {
217		.name   = "raspberrypi-ts",
218		.of_match_table = rpi_ts_match,
219	},
220	.probe          = rpi_ts_probe,
221};
222module_platform_driver(rpi_ts_driver);
223
224MODULE_AUTHOR("Gordon Hollingworth");
225MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
226MODULE_DESCRIPTION("Raspberry Pi firmware based touchscreen driver");
227MODULE_LICENSE("GPL v2");