// SPDX-License-Identifier: GPL-2.0-or-later
|
/*
|
* Driver for a keypad w/16 buttons connected to a PCF8574 I2C I/O expander
|
*
|
* Copyright 2005-2008 Analog Devices Inc.
|
*/
|
|
#include <linux/module.h>
|
#include <linux/input.h>
|
#include <linux/interrupt.h>
|
#include <linux/i2c.h>
|
#include <linux/slab.h>
|
#include <linux/workqueue.h>
|
|
#define DRV_NAME "pcf8574_keypad"
|
|
static const unsigned char pcf8574_kp_btncode[] = {
|
[0] = KEY_RESERVED,
|
[1] = KEY_ENTER,
|
[2] = KEY_BACKSLASH,
|
[3] = KEY_0,
|
[4] = KEY_RIGHTBRACE,
|
[5] = KEY_C,
|
[6] = KEY_9,
|
[7] = KEY_8,
|
[8] = KEY_7,
|
[9] = KEY_B,
|
[10] = KEY_6,
|
[11] = KEY_5,
|
[12] = KEY_4,
|
[13] = KEY_A,
|
[14] = KEY_3,
|
[15] = KEY_2,
|
[16] = KEY_1
|
};
|
|
struct kp_data {
|
unsigned short btncode[ARRAY_SIZE(pcf8574_kp_btncode)];
|
struct input_dev *idev;
|
struct i2c_client *client;
|
char name[64];
|
char phys[32];
|
unsigned char laststate;
|
};
|
|
static short read_state(struct kp_data *lp)
|
{
|
unsigned char x, y, a, b;
|
|
i2c_smbus_write_byte(lp->client, 240);
|
x = 0xF & (~(i2c_smbus_read_byte(lp->client) >> 4));
|
|
i2c_smbus_write_byte(lp->client, 15);
|
y = 0xF & (~i2c_smbus_read_byte(lp->client));
|
|
for (a = 0; x > 0; a++)
|
x = x >> 1;
|
for (b = 0; y > 0; b++)
|
y = y >> 1;
|
|
return ((a - 1) * 4) + b;
|
}
|
|
static irqreturn_t pcf8574_kp_irq_handler(int irq, void *dev_id)
|
{
|
struct kp_data *lp = dev_id;
|
unsigned char nextstate = read_state(lp);
|
|
if (lp->laststate != nextstate) {
|
int key_down = nextstate < ARRAY_SIZE(lp->btncode);
|
unsigned short keycode = key_down ?
|
lp->btncode[nextstate] : lp->btncode[lp->laststate];
|
|
input_report_key(lp->idev, keycode, key_down);
|
input_sync(lp->idev);
|
|
lp->laststate = nextstate;
|
}
|
|
return IRQ_HANDLED;
|
}
|
|
static int pcf8574_kp_probe(struct i2c_client *client, const struct i2c_device_id *id)
|
{
|
int i, ret;
|
struct input_dev *idev;
|
struct kp_data *lp;
|
|
if (i2c_smbus_write_byte(client, 240) < 0) {
|
dev_err(&client->dev, "probe: write fail\n");
|
return -ENODEV;
|
}
|
|
lp = kzalloc(sizeof(*lp), GFP_KERNEL);
|
if (!lp)
|
return -ENOMEM;
|
|
idev = input_allocate_device();
|
if (!idev) {
|
dev_err(&client->dev, "Can't allocate input device\n");
|
ret = -ENOMEM;
|
goto fail_allocate;
|
}
|
|
lp->idev = idev;
|
lp->client = client;
|
|
idev->evbit[0] = BIT_MASK(EV_KEY);
|
idev->keycode = lp->btncode;
|
idev->keycodesize = sizeof(lp->btncode[0]);
|
idev->keycodemax = ARRAY_SIZE(lp->btncode);
|
|
for (i = 0; i < ARRAY_SIZE(pcf8574_kp_btncode); i++) {
|
if (lp->btncode[i] <= KEY_MAX) {
|
lp->btncode[i] = pcf8574_kp_btncode[i];
|
__set_bit(lp->btncode[i], idev->keybit);
|
}
|
}
|
__clear_bit(KEY_RESERVED, idev->keybit);
|
|
sprintf(lp->name, DRV_NAME);
|
sprintf(lp->phys, "kp_data/input0");
|
|
idev->name = lp->name;
|
idev->phys = lp->phys;
|
idev->id.bustype = BUS_I2C;
|
idev->id.vendor = 0x0001;
|
idev->id.product = 0x0001;
|
idev->id.version = 0x0100;
|
|
lp->laststate = read_state(lp);
|
|
ret = request_threaded_irq(client->irq, NULL, pcf8574_kp_irq_handler,
|
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
|
DRV_NAME, lp);
|
if (ret) {
|
dev_err(&client->dev, "IRQ %d is not free\n", client->irq);
|
goto fail_free_device;
|
}
|
|
ret = input_register_device(idev);
|
if (ret) {
|
dev_err(&client->dev, "input_register_device() failed\n");
|
goto fail_free_irq;
|
}
|
|
i2c_set_clientdata(client, lp);
|
return 0;
|
|
fail_free_irq:
|
free_irq(client->irq, lp);
|
fail_free_device:
|
input_free_device(idev);
|
fail_allocate:
|
kfree(lp);
|
|
return ret;
|
}
|
|
static int pcf8574_kp_remove(struct i2c_client *client)
|
{
|
struct kp_data *lp = i2c_get_clientdata(client);
|
|
free_irq(client->irq, lp);
|
|
input_unregister_device(lp->idev);
|
kfree(lp);
|
|
return 0;
|
}
|
|
#ifdef CONFIG_PM
|
static int pcf8574_kp_resume(struct device *dev)
|
{
|
struct i2c_client *client = to_i2c_client(dev);
|
|
enable_irq(client->irq);
|
|
return 0;
|
}
|
|
static int pcf8574_kp_suspend(struct device *dev)
|
{
|
struct i2c_client *client = to_i2c_client(dev);
|
|
disable_irq(client->irq);
|
|
return 0;
|
}
|
|
static const struct dev_pm_ops pcf8574_kp_pm_ops = {
|
.suspend = pcf8574_kp_suspend,
|
.resume = pcf8574_kp_resume,
|
};
|
|
#else
|
# define pcf8574_kp_resume NULL
|
# define pcf8574_kp_suspend NULL
|
#endif
|
|
static const struct i2c_device_id pcf8574_kp_id[] = {
|
{ DRV_NAME, 0 },
|
{ }
|
};
|
MODULE_DEVICE_TABLE(i2c, pcf8574_kp_id);
|
|
static struct i2c_driver pcf8574_kp_driver = {
|
.driver = {
|
.name = DRV_NAME,
|
#ifdef CONFIG_PM
|
.pm = &pcf8574_kp_pm_ops,
|
#endif
|
},
|
.probe = pcf8574_kp_probe,
|
.remove = pcf8574_kp_remove,
|
.id_table = pcf8574_kp_id,
|
};
|
|
module_i2c_driver(pcf8574_kp_driver);
|
|
MODULE_AUTHOR("Michael Hennerich");
|
MODULE_DESCRIPTION("Keypad input driver for 16 keys connected to PCF8574");
|
MODULE_LICENSE("GPL");
|
