input/keyboard/dlink-dir685-touchkeys.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * D-Link DIR-685 router I2C-based Touchkeys input driver
0004  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
0005  *
0006  * This is a one-off touchkey controller based on the Cypress Semiconductor
0007  * CY8C214 MCU with some firmware in its internal 8KB flash. The circuit
0008  * board inside the router is named E119921
0009  */
0010
0011 #include <linux/module.h>
0012 #include <linux/i2c.h>
0013 #include <linux/interrupt.h>
0014 #include <linux/delay.h>
0015 #include <linux/input.h>
0016 #include <linux/slab.h>
0017 #include <linux/bitops.h>
0018
0019 struct dir685_touchkeys {
0020     struct device       *dev;
0021     struct i2c_client   *client;
0022     struct input_dev    *input;
0023     unsigned long       cur_key;
0024     u16         codes[7];
0025 };
0026
0027 static irqreturn_t dir685_tk_irq_thread(int irq, void *data)
0028 {
0029     struct dir685_touchkeys *tk = data;
0030     const int num_bits = min_t(int, ARRAY_SIZE(tk->codes), 16);
0031     unsigned long changed;
0032     u8 buf[6];
0033     unsigned long key;
0034     int i;
0035     int err;
0036
0037     memset(buf, 0, sizeof(buf));
0038     err = i2c_master_recv(tk->client, buf, sizeof(buf));
0039     if (err != sizeof(buf)) {
0040         dev_err(tk->dev, "short read %d\n", err);
0041         return IRQ_HANDLED;
0042     }
0043
0044     dev_dbg(tk->dev, "IN: %*ph\n", (int)sizeof(buf), buf);
0045     key = be16_to_cpup((__be16 *) &buf[4]);
0046
0047     /* Figure out if any bits went high or low since last message */
0048     changed = tk->cur_key ^ key;
0049     for_each_set_bit(i, &changed, num_bits) {
0050         dev_dbg(tk->dev, "key %d is %s\n", i,
0051             test_bit(i, &key) ? "down" : "up");
0052         input_report_key(tk->input, tk->codes[i], test_bit(i, &key));
0053     }
0054
0055     /* Store currently down keys */
0056     tk->cur_key = key;
0057     input_sync(tk->input);
0058
0059     return IRQ_HANDLED;
0060 }
0061
0062 static int dir685_tk_probe(struct i2c_client *client,
0063                const struct i2c_device_id *id)
0064 {
0065     struct dir685_touchkeys *tk;
0066     struct device *dev = &client->dev;
0067     u8 bl_data[] = { 0xa7, 0x40 };
0068     int err;
0069     int i;
0070
0071     tk = devm_kzalloc(&client->dev, sizeof(*tk), GFP_KERNEL);
0072     if (!tk)
0073         return -ENOMEM;
0074
0075     tk->input = devm_input_allocate_device(dev);
0076     if (!tk->input)
0077         return -ENOMEM;
0078
0079     tk->client = client;
0080     tk->dev = dev;
0081
0082     tk->input->keycodesize = sizeof(u16);
0083     tk->input->keycodemax = ARRAY_SIZE(tk->codes);
0084     tk->input->keycode = tk->codes;
0085     tk->codes[0] = KEY_UP;
0086     tk->codes[1] = KEY_DOWN;
0087     tk->codes[2] = KEY_LEFT;
0088     tk->codes[3] = KEY_RIGHT;
0089     tk->codes[4] = KEY_ENTER;
0090     tk->codes[5] = KEY_WPS_BUTTON;
0091     /*
0092      * This key appears in the vendor driver, but I have
0093      * not been able to activate it.
0094      */
0095     tk->codes[6] = KEY_RESERVED;
0096
0097     __set_bit(EV_KEY, tk->input->evbit);
0098     for (i = 0; i < ARRAY_SIZE(tk->codes); i++)
0099         __set_bit(tk->codes[i], tk->input->keybit);
0100     __clear_bit(KEY_RESERVED, tk->input->keybit);
0101
0102     tk->input->name = "D-Link DIR-685 touchkeys";
0103     tk->input->id.bustype = BUS_I2C;
0104
0105     err = input_register_device(tk->input);
0106     if (err)
0107         return err;
0108
0109     /* Set the brightness to max level */
0110     err = i2c_master_send(client, bl_data, sizeof(bl_data));
0111     if (err != sizeof(bl_data))
0112         dev_warn(tk->dev, "error setting brightness level\n");
0113
0114     if (!client->irq) {
0115         dev_err(dev, "no IRQ on the I2C device\n");
0116         return -ENODEV;
0117     }
0118     err = devm_request_threaded_irq(dev, client->irq,
0119                     NULL, dir685_tk_irq_thread,
0120                     IRQF_ONESHOT,
0121                     "dir685-tk", tk);
0122     if (err) {
0123         dev_err(dev, "can't request IRQ\n");
0124         return err;
0125     }
0126
0127     return 0;
0128 }
0129
0130 static const struct i2c_device_id dir685_tk_id[] = {
0131     { "dir685tk", 0 },
0132     { }
0133 };
0134 MODULE_DEVICE_TABLE(i2c, dir685_tk_id);
0135
0136 #ifdef CONFIG_OF
0137 static const struct of_device_id dir685_tk_of_match[] = {
0138     { .compatible = "dlink,dir685-touchkeys" },
0139     {},
0140 };
0141 MODULE_DEVICE_TABLE(of, dir685_tk_of_match);
0142 #endif
0143
0144 static struct i2c_driver dir685_tk_i2c_driver = {
0145     .driver = {
0146         .name   = "dlink-dir685-touchkeys",
0147         .of_match_table = of_match_ptr(dir685_tk_of_match),
0148     },
0149     .probe      = dir685_tk_probe,
0150     .id_table   = dir685_tk_id,
0151 };
0152 module_i2c_driver(dir685_tk_i2c_driver);
0153
0154 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
0155 MODULE_DESCRIPTION("D-Link DIR-685 touchkeys driver");
0156 MODULE_LICENSE("GPL");