LXR linux/drivers/input/keyboard/dlink-dir685-touchkeys.c

   1/*
   2 * D-Link DIR-685 router I2C-based Touchkeys input driver
   3 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   4 *
   5 * This is a one-off touchkey controller based on the Cypress Semiconductor
   6 * CY8C214 MCU with some firmware in its internal 8KB flash. The circuit
   7 * board inside the router is named E119921
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/i2c.h>
  12#include <linux/interrupt.h>
  13#include <linux/delay.h>
  14#include <linux/input.h>
  15#include <linux/slab.h>
  16#include <linux/bitops.h>
  17
  18struct dir685_touchkeys {
  19        struct device           *dev;
  20        struct i2c_client       *client;
  21        struct input_dev        *input;
  22        unsigned long           cur_key;
  23        u16                     codes[7];
  24};
  25
  26static irqreturn_t dir685_tk_irq_thread(int irq, void *data)
  27{
  28        struct dir685_touchkeys *tk = data;
  29        const int num_bits = min_t(int, ARRAY_SIZE(tk->codes), 16);
  30        unsigned long changed;
  31        u8 buf[6];
  32        unsigned long key;
  33        int i;
  34        int err;
  35
  36        memset(buf, 0, sizeof(buf));
  37        err = i2c_master_recv(tk->client, buf, sizeof(buf));
  38        if (err != sizeof(buf)) {
  39                dev_err(tk->dev, "short read %d\n", err);
  40                return IRQ_HANDLED;
  41        }
  42
  43        dev_dbg(tk->dev, "IN: %*ph\n", (int)sizeof(buf), buf);
  44        key = be16_to_cpup((__be16 *) &buf[4]);
  45
  46        /* Figure out if any bits went high or low since last message */
  47        changed = tk->cur_key ^ key;
  48        for_each_set_bit(i, &changed, num_bits) {
  49                dev_dbg(tk->dev, "key %d is %s\n", i,
  50                        test_bit(i, &key) ? "down" : "up");
  51                input_report_key(tk->input, tk->codes[i], test_bit(i, &key));
  52        }
  53
  54        /* Store currently down keys */
  55        tk->cur_key = key;
  56        input_sync(tk->input);
  57
  58        return IRQ_HANDLED;
  59}
  60
  61static int dir685_tk_probe(struct i2c_client *client,
  62                           const struct i2c_device_id *id)
  63{
  64        struct dir685_touchkeys *tk;
  65        struct device *dev = &client->dev;
  66        u8 bl_data[] = { 0xa7, 0x40 };
  67        int err;
  68        int i;
  69
  70        tk = devm_kzalloc(&client->dev, sizeof(*tk), GFP_KERNEL);
  71        if (!tk)
  72                return -ENOMEM;
  73
  74        tk->input = devm_input_allocate_device(dev);
  75        if (!tk->input)
  76                return -ENOMEM;
  77
  78        tk->client = client;
  79        tk->dev = dev;
  80
  81        tk->input->keycodesize = sizeof(u16);
  82        tk->input->keycodemax = ARRAY_SIZE(tk->codes);
  83        tk->input->keycode = tk->codes;
  84        tk->codes[0] = KEY_UP;
  85        tk->codes[1] = KEY_DOWN;
  86        tk->codes[2] = KEY_LEFT;
  87        tk->codes[3] = KEY_RIGHT;
  88        tk->codes[4] = KEY_ENTER;
  89        tk->codes[5] = KEY_WPS_BUTTON;
  90        /*
  91         * This key appears in the vendor driver, but I have
  92         * not been able to activate it.
  93         */
  94        tk->codes[6] = KEY_RESERVED;
  95
  96        __set_bit(EV_KEY, tk->input->evbit);
  97        for (i = 0; i < ARRAY_SIZE(tk->codes); i++)
  98                __set_bit(tk->codes[i], tk->input->keybit);
  99        __clear_bit(KEY_RESERVED, tk->input->keybit);
 100
 101        tk->input->name = "D-Link DIR-685 touchkeys";
 102        tk->input->id.bustype = BUS_I2C;
 103
 104        err = input_register_device(tk->input);
 105        if (err)
 106                return err;
 107
 108        /* Set the brightness to max level */
 109        err = i2c_master_send(client, bl_data, sizeof(bl_data));
 110        if (err != sizeof(bl_data))
 111                dev_warn(tk->dev, "error setting brightness level\n");
 112
 113        if (!client->irq) {
 114                dev_err(dev, "no IRQ on the I2C device\n");
 115                return -ENODEV;
 116        }
 117        err = devm_request_threaded_irq(dev, client->irq,
 118                                        NULL, dir685_tk_irq_thread,
 119                                        IRQF_ONESHOT,
 120                                        "dir685-tk", tk);
 121        if (err) {
 122                dev_err(dev, "can't request IRQ\n");
 123                return err;
 124        }
 125
 126        return 0;
 127}
 128
 129static const struct i2c_device_id dir685_tk_id[] = {
 130        { "dir685tk", 0 },
 131        { }
 132};
 133MODULE_DEVICE_TABLE(i2c, dir685_tk_id);
 134
 135#ifdef CONFIG_OF
 136static const struct of_device_id dir685_tk_of_match[] = {
 137        { .compatible = "dlink,dir685-touchkeys" },
 138        {},
 139};
 140MODULE_DEVICE_TABLE(of, dir685_tk_of_match);
 141#endif
 142
 143static struct i2c_driver dir685_tk_i2c_driver = {
 144        .driver = {
 145                .name   = "dlin-dir685-touchkeys",
 146                .of_match_table = of_match_ptr(dir685_tk_of_match),
 147        },
 148        .probe          = dir685_tk_probe,
 149        .id_table       = dir685_tk_id,
 150};
 151module_i2c_driver(dir685_tk_i2c_driver);
 152
 153MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 154MODULE_DESCRIPTION("D-Link DIR-685 touchkeys driver");
 155MODULE_LICENSE("GPL");
 156