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"); 157