#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio_keys.h>
#include <linux/property.h>
#define DRV_NAME "gpio-keys-polled"
struct gpio_keys_button_data {
struct gpio_desc *gpiod;
int last_state;
int count;
int threshold;
};
struct gpio_keys_polled_dev {
struct input_dev *input;
struct device *dev;
const struct gpio_keys_platform_data *pdata;
unsigned long rel_axis_seen[BITS_TO_LONGS(REL_CNT)];
unsigned long abs_axis_seen[BITS_TO_LONGS(ABS_CNT)];
struct gpio_keys_button_data data[];
};
static void gpio_keys_button_event(struct input_dev *input,
const struct gpio_keys_button *button,
int state)
{
struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
unsigned int type = button->type ?: EV_KEY;
if (type == EV_REL) {
if (state) {
input_event(input, type, button->code, button->value);
__set_bit(button->code, bdev->rel_axis_seen);
}
} else if (type == EV_ABS) {
if (state) {
input_event(input, type, button->code, button->value);
__set_bit(button->code, bdev->abs_axis_seen);
}
} else {
input_event(input, type, button->code, state);
input_sync(input);
}
}
static void gpio_keys_polled_check_state(struct input_dev *input,
const struct gpio_keys_button *button,
struct gpio_keys_button_data *bdata)
{
int state;
state = gpiod_get_value_cansleep(bdata->gpiod);
if (state < 0) {
dev_err(input->dev.parent,
"failed to get gpio state: %d\n", state);
} else {
gpio_keys_button_event(input, button, state);
if (state != bdata->last_state) {
bdata->count = 0;
bdata->last_state = state;
}
}
}
static void gpio_keys_polled_poll(struct input_dev *input)
{
struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
const struct gpio_keys_platform_data *pdata = bdev->pdata;
int i;
memset(bdev->rel_axis_seen, 0, sizeof(bdev->rel_axis_seen));
memset(bdev->abs_axis_seen, 0, sizeof(bdev->abs_axis_seen));
for (i = 0; i < pdata->nbuttons; i++) {
struct gpio_keys_button_data *bdata = &bdev->data[i];
if (bdata->count < bdata->threshold) {
bdata->count++;
gpio_keys_button_event(input, &pdata->buttons[i],
bdata->last_state);
} else {
gpio_keys_polled_check_state(input, &pdata->buttons[i],
bdata);
}
}
for_each_set_bit(i, input->relbit, REL_CNT) {
if (!test_bit(i, bdev->rel_axis_seen))
input_event(input, EV_REL, i, 0);
}
for_each_set_bit(i, input->absbit, ABS_CNT) {
if (!test_bit(i, bdev->abs_axis_seen))
input_event(input, EV_ABS, i, 0);
}
input_sync(input);
}
static int gpio_keys_polled_open(struct input_dev *input)
{
struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
const struct gpio_keys_platform_data *pdata = bdev->pdata;
if (pdata->enable)
pdata->enable(bdev->dev);
return 0;
}
static void gpio_keys_polled_close(struct input_dev *input)
{
struct gpio_keys_polled_dev *bdev = input_get_drvdata(input);
const struct gpio_keys_platform_data *pdata = bdev->pdata;
if (pdata->disable)
pdata->disable(bdev->dev);
}
static struct gpio_keys_platform_data *
gpio_keys_polled_get_devtree_pdata(struct device *dev)
{
struct gpio_keys_platform_data *pdata;
struct gpio_keys_button *button;
int nbuttons;
nbuttons = device_get_child_node_count(dev);
if (nbuttons == 0)
return ERR_PTR(-EINVAL);
pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * sizeof(*button),
GFP_KERNEL);
if (!pdata)
return ERR_PTR(-ENOMEM);
button = (struct gpio_keys_button *)(pdata + 1);
pdata->buttons = button;
pdata->nbuttons = nbuttons;
pdata->rep = device_property_present(dev, "autorepeat");
device_property_read_u32(dev, "poll-interval", &pdata->poll_interval);
device_property_read_string(dev, "label", &pdata->name);
device_for_each_child_node_scoped(dev, child) {
if (fwnode_property_read_u32(child, "linux,code",
&button->code)) {
dev_err(dev, "button without keycode\n");
return ERR_PTR(-EINVAL);
}
fwnode_property_read_string(child, "label", &button->desc);
if (fwnode_property_read_u32(child, "linux,input-type",
&button->type))
button->type = EV_KEY;
if (fwnode_property_read_u32(child, "linux,input-value",
(u32 *)&button->value))
button->value = 1;
button->wakeup =
fwnode_property_read_bool(child, "wakeup-source") ||
fwnode_property_read_bool(child, "gpio-key,wakeup");
if (fwnode_property_read_u32(child, "debounce-interval",
&button->debounce_interval))
button->debounce_interval = 5;
button++;
}
return pdata;
}
static void gpio_keys_polled_set_abs_params(struct input_dev *input,
const struct gpio_keys_platform_data *pdata, unsigned int code)
{
int i, min = 0, max = 0;
for (i = 0; i < pdata->nbuttons; i++) {
const struct gpio_keys_button *button = &pdata->buttons[i];
if (button->type != EV_ABS || button->code != code)
continue;
if (button->value < min)
min = button->value;
if (button->value > max)
max = button->value;
}
input_set_abs_params(input, code, min, max, 0, 0);
}
static const struct of_device_id gpio_keys_polled_of_match[] = {
{ .compatible = "gpio-keys-polled", },
{ },
};
MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
static int gpio_keys_polled_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct fwnode_handle *child = NULL;
const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
struct gpio_keys_polled_dev *bdev;
struct input_dev *input;
int error;
int i;
if (!pdata) {
pdata = gpio_keys_polled_get_devtree_pdata(dev);
if (IS_ERR(pdata))
return PTR_ERR(pdata);
}
if (!pdata->poll_interval) {
dev_err(dev, "missing poll_interval value\n");
return -EINVAL;
}
bdev = devm_kzalloc(dev, struct_size(bdev, data, pdata->nbuttons),
GFP_KERNEL);
if (!bdev) {
dev_err(dev, "no memory for private data\n");
return -ENOMEM;
}
input = devm_input_allocate_device(dev);
if (!input) {
dev_err(dev, "no memory for input device\n");
return -ENOMEM;
}
input_set_drvdata(input, bdev);
input->name = pdata->name ?: pdev->name;
input->phys = DRV_NAME"/input0";
input->id.bustype = BUS_HOST;
input->id.vendor = 0x0001;
input->id.product = 0x0001;
input->id.version = 0x0100;
input->open = gpio_keys_polled_open;
input->close = gpio_keys_polled_close;
__set_bit(EV_KEY, input->evbit);
if (pdata->rep)
__set_bit(EV_REP, input->evbit);
for (i = 0; i < pdata->nbuttons; i++) {
const struct gpio_keys_button *button = &pdata->buttons[i];
struct gpio_keys_button_data *bdata = &bdev->data[i];
unsigned int type = button->type ?: EV_KEY;
if (button->wakeup) {
dev_err(dev, DRV_NAME " does not support wakeup\n");
fwnode_handle_put(child);
return -EINVAL;
}
if (!dev_get_platdata(dev)) {
child = device_get_next_child_node(dev, child);
if (!child) {
dev_err(dev, "missing child device node\n");
return -EINVAL;
}
bdata->gpiod = devm_fwnode_gpiod_get(dev, child,
NULL, GPIOD_IN,
button->desc);
if (IS_ERR(bdata->gpiod)) {
fwnode_handle_put(child);
return dev_err_probe(dev, PTR_ERR(bdata->gpiod),
"failed to get gpio\n");
}
} else if (gpio_is_valid(button->gpio)) {
error = devm_gpio_request_one(dev, button->gpio, GPIOF_IN,
button->desc ? : DRV_NAME);
if (error)
return dev_err_probe(dev, error,
"unable to claim gpio %u\n",
button->gpio);
bdata->gpiod = gpio_to_desc(button->gpio);
if (!bdata->gpiod) {
dev_err(dev,
"unable to convert gpio %u to descriptor\n",
button->gpio);
return -EINVAL;
}
if (button->active_low ^ gpiod_is_active_low(bdata->gpiod))
gpiod_toggle_active_low(bdata->gpiod);
}
bdata->last_state = -1;
bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
pdata->poll_interval);
input_set_capability(input, type, button->code);
if (type == EV_ABS)
gpio_keys_polled_set_abs_params(input, pdata,
button->code);
}
fwnode_handle_put(child);
bdev->input = input;
bdev->dev = dev;
bdev->pdata = pdata;
error = input_setup_polling(input, gpio_keys_polled_poll);
if (error) {
dev_err(dev, "unable to set up polling, err=%d\n", error);
return error;
}
input_set_poll_interval(input, pdata->poll_interval);
error = input_register_device(input);
if (error) {
dev_err(dev, "unable to register polled device, err=%d\n",
error);
return error;
}
for (i = 0; i < pdata->nbuttons; i++)
gpio_keys_polled_check_state(input, &pdata->buttons[i],
&bdev->data[i]);
input_sync(input);
return 0;
}
static struct platform_driver gpio_keys_polled_driver = {
.probe = gpio_keys_polled_probe,
.driver = {
.name = DRV_NAME,
.of_match_table = gpio_keys_polled_of_match,
},
};
module_platform_driver(gpio_keys_polled_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_DESCRIPTION("Polled GPIO Buttons driver");
MODULE_ALIAS("platform:" DRV_NAME);
