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

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * D-Link DIR-685 router I2C-based Touchkeys input driver
   4 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   5 *
   6 * This is a one-off touchkey controller based on the Cypress Semiconductor
   7 * CY8C214 MCU with some firmware in its internal 8KB flash. The circuit
   8 * board inside the router is named E119921
   9 */
  10
  11#include <linux/module.h>
  12#include <linux/i2c.h>
  13#include <linux/interrupt.h>
  14#include <linux/delay.h>
  15#include <linux/input.h>
  16#include <linux/slab.h>
  17#include <linux/bitops.h>
  18
  19struct dir685_touchkeys {
  20        struct device           *dev;
  21        struct i2c_client       *client;
  22        struct input_dev        *input;
  23        unsigned long           cur_key;
  24        u16                     codes[7];
  25};
  26
  27static irqreturn_t dir685_tk_irq_thread(int irq, void *data)
  28{
  29        struct dir685_touchkeys *tk = data;
  30        const int num_bits = min_t(int, ARRAY_SIZE(tk->codes), 16);
  31        unsigned long changed;
  32        u8 buf[6];
  33        unsigned long key;
  34        int i;
  35        int err;
  36
  37        memset(buf, 0, sizeof(buf));
  38        err = i2c_master_recv(tk->client, buf, sizeof(buf));
  39        if (err != sizeof(buf)) {
  40                dev_err(tk->dev, "short read %d\n", err);
  41                return IRQ_HANDLED;
  42        }
  43
  44        dev_dbg(tk->dev, "IN: %*ph\n", (int)sizeof(buf), buf);
  45        key = be16_to_cpup((__be16 *) &buf[4]);
  46
  47        /* Figure out if any bits went high or low since last message */
  48        changed = tk->cur_key ^ key;
  49        for_each_set_bit(i, &changed, num_bits) {
  50                dev_dbg(tk->dev, "key %d is %s\n", i,
  51                        test_bit(i, &key) ? "down" : "up");
  52                input_report_key(tk->input, tk->codes[i], test_bit(i, &key));
  53        }
  54
  55        /* Store currently down keys */
  56        tk->cur_key = key;
  57        input_sync(tk->input);
  58
  59        return IRQ_HANDLED;
  60}
  61
  62static int dir685_tk_probe(struct i2c_client *client,
  63                           const struct i2c_device_id *id)
  64{
  65        struct dir685_touchkeys *tk;
  66        struct device *dev = &client->dev;
  67        u8 bl_data[] = { 0xa7, 0x40 };
  68        int err;
  69        int i;
  70
  71        tk = devm_kzalloc(&client->dev, sizeof(*tk), GFP_KERNEL);
  72        if (!tk)
  73                return -ENOMEM;
  74
  75        tk->input = devm_input_allocate_device(dev);
  76        if (!tk->input)
  77                return -ENOMEM;
  78
  79        tk->client = client;
  80        tk->dev = dev;
  81
  82        tk->input->keycodesize = sizeof(u16);
  83        tk->input->keycodemax = ARRAY_SIZE(tk->codes);
  84        tk->input->keycode = tk->codes;
  85        tk->codes[0] = KEY_UP;
  86        tk->codes[1] = KEY_DOWN;
  87        tk->codes[2] = KEY_LEFT;
  88        tk->codes[3] = KEY_RIGHT;
  89        tk->codes[4] = KEY_ENTER;
  90        tk->codes[5] = KEY_WPS_BUTTON;
  91        /*
  92         * This key appears in the vendor driver, but I have
  93         * not been able to activate it.
  94         */
  95        tk->codes[6] = KEY_RESERVED;
  96
  97        __set_bit(EV_KEY, tk->input->evbit);
  98        for (i = 0; i < ARRAY_SIZE(tk->codes); i++)
  99                __set_bit(tk->codes[i], tk->input->keybit);
 100        __clear_bit(KEY_RESERVED, tk->input->keybit);
 101
 102        tk->input->name = "D-Link DIR-685 touchkeys";
 103        tk->input->id.bustype = BUS_I2C;
 104
 105        err = input_register_device(tk->input);
 106        if (err)
 107                return err;
 108
 109        /* Set the brightness to max level */
 110        err = i2c_master_send(client, bl_data, sizeof(bl_data));
 111        if (err != sizeof(bl_data))
 112                dev_warn(tk->dev, "error setting brightness level\n");
 113
 114        if (!client->irq) {
 115                dev_err(dev, "no IRQ on the I2C device\n");
 116                return -ENODEV;
 117        }
 118        err = devm_request_threaded_irq(dev, client->irq,
 119                                        NULL, dir685_tk_irq_thread,
 120                                        IRQF_ONESHOT,
 121                                        "dir685-tk", tk);
 122        if (err) {
 123                dev_err(dev, "can't request IRQ\n");
 124                return err;
 125        }
 126
 127        return 0;
 128}
 129
 130static const struct i2c_device_id dir685_tk_id[] = {
 131        { "dir685tk", 0 },
 132        { }
 133};
 134MODULE_DEVICE_TABLE(i2c, dir685_tk_id);
 135
 136#ifdef CONFIG_OF
 137static const struct of_device_id dir685_tk_of_match[] = {
 138        { .compatible = "dlink,dir685-touchkeys" },
 139        {},
 140};
 141MODULE_DEVICE_TABLE(of, dir685_tk_of_match);
 142#endif
 143
 144static struct i2c_driver dir685_tk_i2c_driver = {
 145        .driver = {
 146                .name   = "dlink-dir685-touchkeys",
 147                .of_match_table = of_match_ptr(dir685_tk_of_match),
 148        },
 149        .probe          = dir685_tk_probe,
 150        .id_table       = dir685_tk_id,
 151};
 152module_i2c_driver(dir685_tk_i2c_driver);
 153
 154MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 155MODULE_DESCRIPTION("D-Link DIR-685 touchkeys driver");
 156MODULE_LICENSE("GPL");
 157