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