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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gpio-tpic2810.c (3991B)

      1/*
      2 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
      3 *	Andrew F. Davis <afd@ti.com>
      4 *
      5 * This program is free software; you can redistribute it and/or
      6 * modify it under the terms of the GNU General Public License version 2 as
      7 * published by the Free Software Foundation.
      8 *
      9 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
     10 * kind, whether expressed or implied; without even the implied warranty
     11 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     12 * GNU General Public License version 2 for more details.
     13 */
     14
     15#include <linux/gpio/driver.h>
     16#include <linux/i2c.h>
     17#include <linux/module.h>
     18#include <linux/mutex.h>
     19
     20#define TPIC2810_WS_COMMAND 0x44
     21
     22/**
     23 * struct tpic2810 - GPIO driver data
     24 * @chip: GPIO controller chip
     25 * @client: I2C device pointer
     26 * @buffer: Buffer for device register
     27 * @lock: Protects write sequences
     28 */
     29struct tpic2810 {
     30	struct gpio_chip chip;
     31	struct i2c_client *client;
     32	u8 buffer;
     33	struct mutex lock;
     34};
     35
     36static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value);
     37
     38static int tpic2810_get_direction(struct gpio_chip *chip,
     39				  unsigned offset)
     40{
     41	/* This device always output */
     42	return GPIO_LINE_DIRECTION_OUT;
     43}
     44
     45static int tpic2810_direction_input(struct gpio_chip *chip,
     46				    unsigned offset)
     47{
     48	/* This device is output only */
     49	return -EINVAL;
     50}
     51
     52static int tpic2810_direction_output(struct gpio_chip *chip,
     53				     unsigned offset, int value)
     54{
     55	/* This device always output */
     56	tpic2810_set(chip, offset, value);
     57	return 0;
     58}
     59
     60static void tpic2810_set_mask_bits(struct gpio_chip *chip, u8 mask, u8 bits)
     61{
     62	struct tpic2810 *gpio = gpiochip_get_data(chip);
     63	u8 buffer;
     64	int err;
     65
     66	mutex_lock(&gpio->lock);
     67
     68	buffer = gpio->buffer & ~mask;
     69	buffer |= (mask & bits);
     70
     71	err = i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,
     72					buffer);
     73	if (!err)
     74		gpio->buffer = buffer;
     75
     76	mutex_unlock(&gpio->lock);
     77}
     78
     79static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value)
     80{
     81	tpic2810_set_mask_bits(chip, BIT(offset), value ? BIT(offset) : 0);
     82}
     83
     84static void tpic2810_set_multiple(struct gpio_chip *chip, unsigned long *mask,
     85				  unsigned long *bits)
     86{
     87	tpic2810_set_mask_bits(chip, *mask, *bits);
     88}
     89
     90static const struct gpio_chip template_chip = {
     91	.label			= "tpic2810",
     92	.owner			= THIS_MODULE,
     93	.get_direction		= tpic2810_get_direction,
     94	.direction_input	= tpic2810_direction_input,
     95	.direction_output	= tpic2810_direction_output,
     96	.set			= tpic2810_set,
     97	.set_multiple		= tpic2810_set_multiple,
     98	.base			= -1,
     99	.ngpio			= 8,
    100	.can_sleep		= true,
    101};
    102
    103static const struct of_device_id tpic2810_of_match_table[] = {
    104	{ .compatible = "ti,tpic2810" },
    105	{ /* sentinel */ }
    106};
    107MODULE_DEVICE_TABLE(of, tpic2810_of_match_table);
    108
    109static int tpic2810_probe(struct i2c_client *client,
    110			  const struct i2c_device_id *id)
    111{
    112	struct tpic2810 *gpio;
    113	int ret;
    114
    115	gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
    116	if (!gpio)
    117		return -ENOMEM;
    118
    119	i2c_set_clientdata(client, gpio);
    120
    121	gpio->chip = template_chip;
    122	gpio->chip.parent = &client->dev;
    123
    124	gpio->client = client;
    125
    126	mutex_init(&gpio->lock);
    127
    128	ret = gpiochip_add_data(&gpio->chip, gpio);
    129	if (ret < 0) {
    130		dev_err(&client->dev, "Unable to register gpiochip\n");
    131		return ret;
    132	}
    133
    134	return 0;
    135}
    136
    137static int tpic2810_remove(struct i2c_client *client)
    138{
    139	struct tpic2810 *gpio = i2c_get_clientdata(client);
    140
    141	gpiochip_remove(&gpio->chip);
    142
    143	return 0;
    144}
    145
    146static const struct i2c_device_id tpic2810_id_table[] = {
    147	{ "tpic2810", },
    148	{ /* sentinel */ }
    149};
    150MODULE_DEVICE_TABLE(i2c, tpic2810_id_table);
    151
    152static struct i2c_driver tpic2810_driver = {
    153	.driver = {
    154		.name = "tpic2810",
    155		.of_match_table = tpic2810_of_match_table,
    156	},
    157	.probe = tpic2810_probe,
    158	.remove = tpic2810_remove,
    159	.id_table = tpic2810_id_table,
    160};
    161module_i2c_driver(tpic2810_driver);
    162
    163MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
    164MODULE_DESCRIPTION("TPIC2810 8-Bit LED Driver GPIO Driver");
    165MODULE_LICENSE("GPL v2");