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-moxtet.c (4178B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 *  Turris Mox Moxtet GPIO expander
      4 *
      5 *  Copyright (C) 2018 Marek Behún <kabel@kernel.org>
      6 */
      7
      8#include <linux/bitops.h>
      9#include <linux/gpio/driver.h>
     10#include <linux/moxtet.h>
     11#include <linux/module.h>
     12
     13#define MOXTET_GPIO_NGPIOS	12
     14#define MOXTET_GPIO_INPUTS	4
     15
     16struct moxtet_gpio_desc {
     17	u16 in_mask;
     18	u16 out_mask;
     19};
     20
     21static const struct moxtet_gpio_desc descs[] = {
     22	[TURRIS_MOX_MODULE_SFP] = {
     23		.in_mask = GENMASK(2, 0),
     24		.out_mask = GENMASK(5, 4),
     25	},
     26};
     27
     28struct moxtet_gpio_chip {
     29	struct device			*dev;
     30	struct gpio_chip		gpio_chip;
     31	const struct moxtet_gpio_desc	*desc;
     32};
     33
     34static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
     35{
     36	struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
     37	int ret;
     38
     39	if (chip->desc->in_mask & BIT(offset)) {
     40		ret = moxtet_device_read(chip->dev);
     41	} else if (chip->desc->out_mask & BIT(offset)) {
     42		ret = moxtet_device_written(chip->dev);
     43		if (ret >= 0)
     44			ret <<= MOXTET_GPIO_INPUTS;
     45	} else {
     46		return -EINVAL;
     47	}
     48
     49	if (ret < 0)
     50		return ret;
     51
     52	return !!(ret & BIT(offset));
     53}
     54
     55static void moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
     56				  int val)
     57{
     58	struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
     59	int state;
     60
     61	state = moxtet_device_written(chip->dev);
     62	if (state < 0)
     63		return;
     64
     65	offset -= MOXTET_GPIO_INPUTS;
     66
     67	if (val)
     68		state |= BIT(offset);
     69	else
     70		state &= ~BIT(offset);
     71
     72	moxtet_device_write(chip->dev, state);
     73}
     74
     75static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
     76{
     77	struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
     78
     79	/* All lines are hard wired to be either input or output, not both. */
     80	if (chip->desc->in_mask & BIT(offset))
     81		return GPIO_LINE_DIRECTION_IN;
     82	else if (chip->desc->out_mask & BIT(offset))
     83		return GPIO_LINE_DIRECTION_OUT;
     84	else
     85		return -EINVAL;
     86}
     87
     88static int moxtet_gpio_direction_input(struct gpio_chip *gc,
     89				       unsigned int offset)
     90{
     91	struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
     92
     93	if (chip->desc->in_mask & BIT(offset))
     94		return 0;
     95	else if (chip->desc->out_mask & BIT(offset))
     96		return -ENOTSUPP;
     97	else
     98		return -EINVAL;
     99}
    100
    101static int moxtet_gpio_direction_output(struct gpio_chip *gc,
    102					unsigned int offset, int val)
    103{
    104	struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
    105
    106	if (chip->desc->out_mask & BIT(offset))
    107		moxtet_gpio_set_value(gc, offset, val);
    108	else if (chip->desc->in_mask & BIT(offset))
    109		return -ENOTSUPP;
    110	else
    111		return -EINVAL;
    112
    113	return 0;
    114}
    115
    116static int moxtet_gpio_probe(struct device *dev)
    117{
    118	struct moxtet_gpio_chip *chip;
    119	struct device_node *nc = dev->of_node;
    120	int id;
    121
    122	id = to_moxtet_device(dev)->id;
    123
    124	if (id >= ARRAY_SIZE(descs)) {
    125		dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n",
    126			nc, id);
    127		return -ENOTSUPP;
    128	}
    129
    130	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
    131	if (!chip)
    132		return -ENOMEM;
    133
    134	chip->dev = dev;
    135	chip->gpio_chip.parent = dev;
    136	chip->desc = &descs[id];
    137
    138	dev_set_drvdata(dev, chip);
    139
    140	chip->gpio_chip.label = dev_name(dev);
    141	chip->gpio_chip.get_direction = moxtet_gpio_get_direction;
    142	chip->gpio_chip.direction_input = moxtet_gpio_direction_input;
    143	chip->gpio_chip.direction_output = moxtet_gpio_direction_output;
    144	chip->gpio_chip.get = moxtet_gpio_get_value;
    145	chip->gpio_chip.set = moxtet_gpio_set_value;
    146	chip->gpio_chip.base = -1;
    147
    148	chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS;
    149
    150	chip->gpio_chip.can_sleep = true;
    151	chip->gpio_chip.owner = THIS_MODULE;
    152
    153	return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip);
    154}
    155
    156static const struct of_device_id moxtet_gpio_dt_ids[] = {
    157	{ .compatible = "cznic,moxtet-gpio", },
    158	{},
    159};
    160MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids);
    161
    162static const enum turris_mox_module_id moxtet_gpio_module_table[] = {
    163	TURRIS_MOX_MODULE_SFP,
    164	0,
    165};
    166
    167static struct moxtet_driver moxtet_gpio_driver = {
    168	.driver = {
    169		.name		= "moxtet-gpio",
    170		.of_match_table	= moxtet_gpio_dt_ids,
    171		.probe		= moxtet_gpio_probe,
    172	},
    173	.id_table = moxtet_gpio_module_table,
    174};
    175module_moxtet_driver(moxtet_gpio_driver);
    176
    177MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
    178MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander");
    179MODULE_LICENSE("GPL v2");