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
  19 struct 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
  27 static 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
  62 static 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
 130 static const struct i2c_device_id dir685_tk_id[] = {
 131         { "dir685tk", 0 },
 132         { }
 133 };
 134 MODULE_DEVICE_TABLE(i2c, dir685_tk_id);
 135
 136 #ifdef CONFIG_OF
 137 static const struct of_device_id dir685_tk_of_match[] = {
 138         { .compatible = "dlink,dir685-touchkeys" },
 139         {},
 140 };
 141 MODULE_DEVICE_TABLE(of, dir685_tk_of_match);
 142 #endif
 143
 144 static 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 };
 152 module_i2c_driver(dir685_tk_i2c_driver);
 153
 154 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 155 MODULE_DESCRIPTION("D-Link DIR-685 touchkeys driver");
 156 MODULE_LICENSE("GPL");