diff options
Diffstat (limited to 'drivers/input/misc/pcf8574_keypad.c')
| -rw-r--r-- | drivers/input/misc/pcf8574_keypad.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/drivers/input/misc/pcf8574_keypad.c b/drivers/input/misc/pcf8574_keypad.c new file mode 100644 index 000000000..cfd6640e4 --- /dev/null +++ b/drivers/input/misc/pcf8574_keypad.c @@ -0,0 +1,221 @@ +// 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 void 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); +} + +#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"); |