1/*
  2 * Touchscreen driver for the TS-4800 board
  3 *
  4 * Copyright (c) 2015 - Savoir-faire Linux
  5 *
  6 * This file is licensed under the terms of the GNU General Public
  7 * License version 2. This program is licensed "as is" without any
  8 * warranty of any kind, whether express or implied.
  9 */
 10
 11#include <linux/bitops.h>
 12#include <linux/input.h>
 13#include <linux/input-polldev.h>
 14#include <linux/io.h>
 15#include <linux/kernel.h>
 16#include <linux/mfd/syscon.h>
 17#include <linux/module.h>
 18#include <linux/of.h>
 19#include <linux/platform_device.h>
 20#include <linux/regmap.h>
 21
 22/* polling interval in ms */
 23#define POLL_INTERVAL		3
 24
 25#define DEBOUNCE_COUNT		1
 26
 27/* sensor values are 12-bit wide */
 28#define MAX_12BIT		((1 << 12) - 1)
 29
 30#define PENDOWN_MASK		0x1
 31
 32#define X_OFFSET		0x0
 33#define Y_OFFSET		0x2
 34
 35struct ts4800_ts {
 36	struct input_polled_dev *poll_dev;
 37	struct device           *dev;
 38	char                    phys[32];
 39
 40	void __iomem            *base;
 41	struct regmap           *regmap;
 42	unsigned int            reg;
 43	unsigned int            bit;
 44
 45	bool                    pendown;
 46	int                     debounce;
 47};
 48
 49static void ts4800_ts_open(struct input_polled_dev *dev)
 50{
 51	struct ts4800_ts *ts = dev->private;
 52	int ret;
 53
 54	ts->pendown = false;
 55	ts->debounce = DEBOUNCE_COUNT;
 56
 57	ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
 58	if (ret)
 59		dev_warn(ts->dev, "Failed to enable touchscreen\n");
 60}
 61
 62static void ts4800_ts_close(struct input_polled_dev *dev)
 63{
 64	struct ts4800_ts *ts = dev->private;
 65	int ret;
 66
 67	ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
 68	if (ret)
 69		dev_warn(ts->dev, "Failed to disable touchscreen\n");
 70
 71}
 72
 73static void ts4800_ts_poll(struct input_polled_dev *dev)
 74{
 75	struct input_dev *input_dev = dev->input;
 76	struct ts4800_ts *ts = dev->private;
 77	u16 last_x = readw(ts->base + X_OFFSET);
 78	u16 last_y = readw(ts->base + Y_OFFSET);
 79	bool pendown = last_x & PENDOWN_MASK;
 80
 81	if (pendown) {
 82		if (ts->debounce) {
 83			ts->debounce--;
 84			return;
 85		}
 86
 87		if (!ts->pendown) {
 88			input_report_key(input_dev, BTN_TOUCH, 1);
 89			ts->pendown = true;
 90		}
 91
 92		last_x = ((~last_x) >> 4) & MAX_12BIT;
 93		last_y = ((~last_y) >> 4) & MAX_12BIT;
 94
 95		input_report_abs(input_dev, ABS_X, last_x);
 96		input_report_abs(input_dev, ABS_Y, last_y);
 97		input_sync(input_dev);
 98	} else if (ts->pendown) {
 99		ts->pendown = false;
100		ts->debounce = DEBOUNCE_COUNT;
101		input_report_key(input_dev, BTN_TOUCH, 0);
102		input_sync(input_dev);
103	}
104}
105
106static int ts4800_parse_dt(struct platform_device *pdev,
107			   struct ts4800_ts *ts)
108{
109	struct device *dev = &pdev->dev;
110	struct device_node *np = dev->of_node;
111	struct device_node *syscon_np;
112	u32 reg, bit;
113	int error;
114
115	syscon_np = of_parse_phandle(np, "syscon", 0);
116	if (!syscon_np) {
117		dev_err(dev, "no syscon property\n");
118		return -ENODEV;
119	}
120
121	error = of_property_read_u32_index(np, "syscon", 1, &reg);
122	if (error < 0) {
123		dev_err(dev, "no offset in syscon\n");
124		return error;
125	}
126
127	ts->reg = reg;
128
129	error = of_property_read_u32_index(np, "syscon", 2, &bit);
130	if (error < 0) {
131		dev_err(dev, "no bit in syscon\n");
132		return error;
133	}
134
135	ts->bit = BIT(bit);
136
137	ts->regmap = syscon_node_to_regmap(syscon_np);
138	if (IS_ERR(ts->regmap)) {
139		dev_err(dev, "cannot get parent's regmap\n");
140		return PTR_ERR(ts->regmap);
141	}
142
143	return 0;
144}
145
146static int ts4800_ts_probe(struct platform_device *pdev)
147{
148	struct input_polled_dev *poll_dev;
149	struct ts4800_ts *ts;
150	struct resource *res;
151	int error;
152
153	ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
154	if (!ts)
155		return -ENOMEM;
156
157	error = ts4800_parse_dt(pdev, ts);
158	if (error)
159		return error;
160
161	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
162	ts->base = devm_ioremap_resource(&pdev->dev, res);
163	if (IS_ERR(ts->base))
164		return PTR_ERR(ts->base);
165
166	poll_dev = devm_input_allocate_polled_device(&pdev->dev);
167	if (!poll_dev)
168		return -ENOMEM;
169
170	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
171	ts->poll_dev = poll_dev;
172	ts->dev = &pdev->dev;
173
174	poll_dev->private = ts;
175	poll_dev->poll_interval = POLL_INTERVAL;
176	poll_dev->open = ts4800_ts_open;
177	poll_dev->close = ts4800_ts_close;
178	poll_dev->poll = ts4800_ts_poll;
179
180	poll_dev->input->name = "TS-4800 Touchscreen";
181	poll_dev->input->phys = ts->phys;
182
183	input_set_capability(poll_dev->input, EV_KEY, BTN_TOUCH);
184	input_set_abs_params(poll_dev->input, ABS_X, 0, MAX_12BIT, 0, 0);
185	input_set_abs_params(poll_dev->input, ABS_Y, 0, MAX_12BIT, 0, 0);
186
187	error = input_register_polled_device(poll_dev);
188	if (error) {
189		dev_err(&pdev->dev,
190			"Unabled to register polled input device (%d)\n",
191			error);
192		return error;
193	}
194
195	return 0;
196}
197
198static const struct of_device_id ts4800_ts_of_match[] = {
199	{ .compatible = "technologic,ts4800-ts", },
200	{ },
201};
202MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
203
204static struct platform_driver ts4800_ts_driver = {
205	.driver = {
206		.name = "ts4800-ts",
207		.of_match_table = ts4800_ts_of_match,
208	},
209	.probe = ts4800_ts_probe,
210};
211module_platform_driver(ts4800_ts_driver);
212
213MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
214MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
215MODULE_LICENSE("GPL v2");
216MODULE_ALIAS("platform:ts4800_ts");