cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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dlink-dir685-touchkeys.c (3929B)

      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");