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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adg792a.c (3650B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
      4 *
      5 * Copyright (C) 2017 Axentia Technologies AB
      6 *
      7 * Author: Peter Rosin <peda@axentia.se>
      8 */
      9
     10#include <linux/err.h>
     11#include <linux/i2c.h>
     12#include <linux/module.h>
     13#include <linux/mux/driver.h>
     14#include <linux/property.h>
     15
     16#define ADG792A_LDSW		BIT(0)
     17#define ADG792A_RESETB		BIT(1)
     18#define ADG792A_DISABLE(mux)	(0x50 | (mux))
     19#define ADG792A_DISABLE_ALL	(0x5f)
     20#define ADG792A_MUX(mux, state)	(0xc0 | (((mux) + 1) << 2) | (state))
     21#define ADG792A_MUX_ALL(state)	(0xc0 | (state))
     22
     23static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset)
     24{
     25	u8 data = ADG792A_RESETB | ADG792A_LDSW;
     26
     27	/* ADG792A_RESETB is active low, the chip resets when it is zero. */
     28	if (reset)
     29		data &= ~ADG792A_RESETB;
     30
     31	return i2c_smbus_write_byte_data(i2c, cmd, data);
     32}
     33
     34static int adg792a_set(struct mux_control *mux, int state)
     35{
     36	struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
     37	u8 cmd;
     38
     39	if (mux->chip->controllers == 1) {
     40		/* parallel mux controller operation */
     41		if (state == MUX_IDLE_DISCONNECT)
     42			cmd = ADG792A_DISABLE_ALL;
     43		else
     44			cmd = ADG792A_MUX_ALL(state);
     45	} else {
     46		unsigned int controller = mux_control_get_index(mux);
     47
     48		if (state == MUX_IDLE_DISCONNECT)
     49			cmd = ADG792A_DISABLE(controller);
     50		else
     51			cmd = ADG792A_MUX(controller, state);
     52	}
     53
     54	return adg792a_write_cmd(i2c, cmd, 0);
     55}
     56
     57static const struct mux_control_ops adg792a_ops = {
     58	.set = adg792a_set,
     59};
     60
     61static int adg792a_probe(struct i2c_client *i2c)
     62{
     63	struct device *dev = &i2c->dev;
     64	struct mux_chip *mux_chip;
     65	s32 idle_state[3];
     66	u32 cells;
     67	int ret;
     68	int i;
     69
     70	if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
     71		return -ENODEV;
     72
     73	ret = device_property_read_u32(dev, "#mux-control-cells", &cells);
     74	if (ret < 0)
     75		return ret;
     76	if (cells >= 2)
     77		return -EINVAL;
     78
     79	mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0);
     80	if (IS_ERR(mux_chip))
     81		return PTR_ERR(mux_chip);
     82
     83	mux_chip->ops = &adg792a_ops;
     84
     85	ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1);
     86	if (ret < 0)
     87		return ret;
     88
     89	ret = device_property_read_u32_array(dev, "idle-state",
     90					     (u32 *)idle_state,
     91					     mux_chip->controllers);
     92	if (ret < 0) {
     93		idle_state[0] = MUX_IDLE_AS_IS;
     94		idle_state[1] = MUX_IDLE_AS_IS;
     95		idle_state[2] = MUX_IDLE_AS_IS;
     96	}
     97
     98	for (i = 0; i < mux_chip->controllers; ++i) {
     99		struct mux_control *mux = &mux_chip->mux[i];
    100
    101		mux->states = 4;
    102
    103		switch (idle_state[i]) {
    104		case MUX_IDLE_DISCONNECT:
    105		case MUX_IDLE_AS_IS:
    106		case 0 ... 4:
    107			mux->idle_state = idle_state[i];
    108			break;
    109		default:
    110			dev_err(dev, "invalid idle-state %d\n", idle_state[i]);
    111			return -EINVAL;
    112		}
    113	}
    114
    115	ret = devm_mux_chip_register(dev, mux_chip);
    116	if (ret < 0)
    117		return ret;
    118
    119	if (cells)
    120		dev_info(dev, "3x single pole quadruple throw muxes registered\n");
    121	else
    122		dev_info(dev, "triple pole quadruple throw mux registered\n");
    123
    124	return 0;
    125}
    126
    127static const struct i2c_device_id adg792a_id[] = {
    128	{ .name = "adg792a", },
    129	{ .name = "adg792g", },
    130	{ }
    131};
    132MODULE_DEVICE_TABLE(i2c, adg792a_id);
    133
    134static const struct of_device_id adg792a_of_match[] = {
    135	{ .compatible = "adi,adg792a", },
    136	{ .compatible = "adi,adg792g", },
    137	{ }
    138};
    139MODULE_DEVICE_TABLE(of, adg792a_of_match);
    140
    141static struct i2c_driver adg792a_driver = {
    142	.driver		= {
    143		.name		= "adg792a",
    144		.of_match_table = of_match_ptr(adg792a_of_match),
    145	},
    146	.probe_new	= adg792a_probe,
    147	.id_table	= adg792a_id,
    148};
    149module_i2c_driver(adg792a_driver);
    150
    151MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
    152MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
    153MODULE_LICENSE("GPL v2");