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 = "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 }; 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"); 156