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
  18 struct 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
  26 static 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
  61 static 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
 129 static const struct i2c_device_id dir685_tk_id[] = {
 130         { "dir685tk", 0 },
 131         { }
 132 };
 133 MODULE_DEVICE_TABLE(i2c, dir685_tk_id);
 134
 135 #ifdef CONFIG_OF
 136 static const struct of_device_id dir685_tk_of_match[] = {
 137         { .compatible = "dlink,dir685-touchkeys" },
 138         {},
 139 };
 140 MODULE_DEVICE_TABLE(of, dir685_tk_of_match);
 141 #endif
 142
 143 static struct i2c_driver dir685_tk_i2c_driver = {
 144         .driver = {
 145                 .name   = "dlink-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 };
 151 module_i2c_driver(dir685_tk_i2c_driver);
 152
 153 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 154 MODULE_DESCRIPTION("D-Link DIR-685 touchkeys driver");
 155 MODULE_LICENSE("GPL");