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.c (2595B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * GPIO-controlled multiplexer driver
      4 *
      5 * Copyright (C) 2017 Axentia Technologies AB
      6 *
      7 * Author: Peter Rosin <peda@axentia.se>
      8 */
      9
     10#include <linux/bitmap.h>
     11#include <linux/err.h>
     12#include <linux/gpio/consumer.h>
     13#include <linux/mod_devicetable.h>
     14#include <linux/module.h>
     15#include <linux/mux/driver.h>
     16#include <linux/platform_device.h>
     17#include <linux/property.h>
     18
     19struct mux_gpio {
     20	struct gpio_descs *gpios;
     21};
     22
     23static int mux_gpio_set(struct mux_control *mux, int state)
     24{
     25	struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
     26	DECLARE_BITMAP(values, BITS_PER_TYPE(state));
     27	u32 value = state;
     28
     29	bitmap_from_arr32(values, &value, BITS_PER_TYPE(value));
     30
     31	gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
     32				       mux_gpio->gpios->desc,
     33				       mux_gpio->gpios->info, values);
     34
     35	return 0;
     36}
     37
     38static const struct mux_control_ops mux_gpio_ops = {
     39	.set = mux_gpio_set,
     40};
     41
     42static const struct of_device_id mux_gpio_dt_ids[] = {
     43	{ .compatible = "gpio-mux", },
     44	{ /* sentinel */ }
     45};
     46MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids);
     47
     48static int mux_gpio_probe(struct platform_device *pdev)
     49{
     50	struct device *dev = &pdev->dev;
     51	struct mux_chip *mux_chip;
     52	struct mux_gpio *mux_gpio;
     53	int pins;
     54	s32 idle_state;
     55	int ret;
     56
     57	pins = gpiod_count(dev, "mux");
     58	if (pins < 0)
     59		return pins;
     60
     61	mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio));
     62	if (IS_ERR(mux_chip))
     63		return PTR_ERR(mux_chip);
     64
     65	mux_gpio = mux_chip_priv(mux_chip);
     66	mux_chip->ops = &mux_gpio_ops;
     67
     68	mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW);
     69	if (IS_ERR(mux_gpio->gpios))
     70		return dev_err_probe(dev, PTR_ERR(mux_gpio->gpios),
     71				     "failed to get gpios\n");
     72	WARN_ON(pins != mux_gpio->gpios->ndescs);
     73	mux_chip->mux->states = BIT(pins);
     74
     75	ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
     76	if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) {
     77		if (idle_state < 0 || idle_state >= mux_chip->mux->states) {
     78			dev_err(dev, "invalid idle-state %u\n", idle_state);
     79			return -EINVAL;
     80		}
     81
     82		mux_chip->mux->idle_state = idle_state;
     83	}
     84
     85	ret = devm_mux_chip_register(dev, mux_chip);
     86	if (ret < 0)
     87		return ret;
     88
     89	dev_info(dev, "%u-way mux-controller registered\n",
     90		 mux_chip->mux->states);
     91
     92	return 0;
     93}
     94
     95static struct platform_driver mux_gpio_driver = {
     96	.driver = {
     97		.name = "gpio-mux",
     98		.of_match_table	= mux_gpio_dt_ids,
     99	},
    100	.probe = mux_gpio_probe,
    101};
    102module_platform_driver(mux_gpio_driver);
    103
    104MODULE_DESCRIPTION("GPIO-controlled multiplexer driver");
    105MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
    106MODULE_LICENSE("GPL v2");