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/*
* Touchscreen driver for the TS-4800 board
*
* Copyright (c) 2015 - Savoir-faire Linux
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/bitops.h>
#include <linux/input.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
/* polling interval in ms */
#define POLL_INTERVAL 3
#define DEBOUNCE_COUNT 1
/* sensor values are 12-bit wide */
#define MAX_12BIT ((1 << 12) - 1)
#define PENDOWN_MASK 0x1
#define X_OFFSET 0x0
#define Y_OFFSET 0x2
struct ts4800_ts {
struct input_dev *input;
struct device *dev;
char phys[32];
void __iomem *base;
struct regmap *regmap;
unsigned int reg;
unsigned int bit;
bool pendown;
int debounce;
};
static int ts4800_ts_open(struct input_dev *input_dev)
{
struct ts4800_ts *ts = input_get_drvdata(input_dev);
int error;
ts->pendown = false;
ts->debounce = DEBOUNCE_COUNT;
error = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
if (error) {
dev_warn(ts->dev, "Failed to enable touchscreen: %d\n", error);
return error;
}
return 0;
}
static void ts4800_ts_close(struct input_dev *input_dev)
{
struct ts4800_ts *ts = input_get_drvdata(input_dev);
int ret;
ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
if (ret)
dev_warn(ts->dev, "Failed to disable touchscreen\n");
}
static void ts4800_ts_poll(struct input_dev *input_dev)
{
struct ts4800_ts *ts = input_get_drvdata(input_dev);
u16 last_x = readw(ts->base + X_OFFSET);
u16 last_y = readw(ts->base + Y_OFFSET);
bool pendown = last_x & PENDOWN_MASK;
if (pendown) {
if (ts->debounce) {
ts->debounce--;
return;
}
if (!ts->pendown) {
input_report_key(input_dev, BTN_TOUCH, 1);
ts->pendown = true;
}
last_x = ((~last_x) >> 4) & MAX_12BIT;
last_y = ((~last_y) >> 4) & MAX_12BIT;
input_report_abs(input_dev, ABS_X, last_x);
input_report_abs(input_dev, ABS_Y, last_y);
input_sync(input_dev);
} else if (ts->pendown) {
ts->pendown = false;
ts->debounce = DEBOUNCE_COUNT;
input_report_key(input_dev, BTN_TOUCH, 0);
input_sync(input_dev);
}
}
static int ts4800_parse_dt(struct platform_device *pdev,
struct ts4800_ts *ts)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct device_node *syscon_np;
u32 reg, bit;
int error;
syscon_np = of_parse_phandle(np, "syscon", 0);
if (!syscon_np) {
dev_err(dev, "no syscon property\n");
return -ENODEV;
}
ts->regmap = syscon_node_to_regmap(syscon_np);
of_node_put(syscon_np);
if (IS_ERR(ts->regmap)) {
dev_err(dev, "cannot get parent's regmap\n");
return PTR_ERR(ts->regmap);
}
error = of_property_read_u32_index(np, "syscon", 1, ®);
if (error < 0) {
dev_err(dev, "no offset in syscon\n");
return error;
}
ts->reg = reg;
error = of_property_read_u32_index(np, "syscon", 2, &bit);
if (error < 0) {
dev_err(dev, "no bit in syscon\n");
return error;
}
ts->bit = BIT(bit);
return 0;
}
static int ts4800_ts_probe(struct platform_device *pdev)
{
struct input_dev *input_dev;
struct ts4800_ts *ts;
int error;
ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
if (!ts)
return -ENOMEM;
error = ts4800_parse_dt(pdev, ts);
if (error)
return error;
ts->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(ts->base))
return PTR_ERR(ts->base);
input_dev = devm_input_allocate_device(&pdev->dev);
if (!input_dev)
return -ENOMEM;
snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
ts->input = input_dev;
ts->dev = &pdev->dev;
input_set_drvdata(input_dev, ts);
input_dev->name = "TS-4800 Touchscreen";
input_dev->phys = ts->phys;
input_dev->open = ts4800_ts_open;
input_dev->close = ts4800_ts_close;
input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
error = input_setup_polling(input_dev, ts4800_ts_poll);
if (error) {
dev_err(&pdev->dev, "Unable to set up polling: %d\n", error);
return error;
}
input_set_poll_interval(input_dev, POLL_INTERVAL);
error = input_register_device(input_dev);
if (error) {
dev_err(&pdev->dev,
"Unable to register input device: %d\n", error);
return error;
}
return 0;
}
static const struct of_device_id ts4800_ts_of_match[] = {
{ .compatible = "technologic,ts4800-ts", },
{ },
};
MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
static struct platform_driver ts4800_ts_driver = {
.driver = {
.name = "ts4800-ts",
.of_match_table = ts4800_ts_of_match,
},
.probe = ts4800_ts_probe,
};
module_platform_driver(ts4800_ts_driver);
MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:ts4800_ts");
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