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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max517.c (4614B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *  max517.c - Support for Maxim MAX517, MAX518 and MAX519
      4 *
      5 *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
      6 */
      7
      8#include <linux/module.h>
      9#include <linux/slab.h>
     10#include <linux/jiffies.h>
     11#include <linux/i2c.h>
     12#include <linux/err.h>
     13
     14#include <linux/iio/iio.h>
     15#include <linux/iio/sysfs.h>
     16#include <linux/iio/dac/max517.h>
     17
     18#define MAX517_DRV_NAME	"max517"
     19
     20/* Commands */
     21#define COMMAND_CHANNEL0	0x00
     22#define COMMAND_CHANNEL1	0x01 /* for MAX518 and MAX519 */
     23#define COMMAND_PD		0x08 /* Power Down */
     24
     25enum max517_device_ids {
     26	ID_MAX517,
     27	ID_MAX518,
     28	ID_MAX519,
     29	ID_MAX520,
     30	ID_MAX521,
     31};
     32
     33struct max517_data {
     34	struct i2c_client	*client;
     35	unsigned short		vref_mv[8];
     36};
     37
     38/*
     39 * channel: bit 0: channel 1
     40 *          bit 1: channel 2
     41 * (this way, it's possible to set both channels at once)
     42 */
     43static int max517_set_value(struct iio_dev *indio_dev,
     44	long val, int channel)
     45{
     46	struct max517_data *data = iio_priv(indio_dev);
     47	struct i2c_client *client = data->client;
     48	u8 outbuf[2];
     49	int res;
     50
     51	if (val < 0 || val > 255)
     52		return -EINVAL;
     53
     54	outbuf[0] = channel;
     55	outbuf[1] = val;
     56
     57	res = i2c_master_send(client, outbuf, 2);
     58	if (res < 0)
     59		return res;
     60	else if (res != 2)
     61		return -EIO;
     62	else
     63		return 0;
     64}
     65
     66static int max517_read_raw(struct iio_dev *indio_dev,
     67			   struct iio_chan_spec const *chan,
     68			   int *val,
     69			   int *val2,
     70			   long m)
     71{
     72	struct max517_data *data = iio_priv(indio_dev);
     73
     74	switch (m) {
     75	case IIO_CHAN_INFO_SCALE:
     76		/* Corresponds to Vref / 2^(bits) */
     77		*val = data->vref_mv[chan->channel];
     78		*val2 = 8;
     79		return IIO_VAL_FRACTIONAL_LOG2;
     80	default:
     81		break;
     82	}
     83	return -EINVAL;
     84}
     85
     86static int max517_write_raw(struct iio_dev *indio_dev,
     87	struct iio_chan_spec const *chan, int val, int val2, long mask)
     88{
     89	int ret;
     90
     91	switch (mask) {
     92	case IIO_CHAN_INFO_RAW:
     93		ret = max517_set_value(indio_dev, val, chan->channel);
     94		break;
     95	default:
     96		ret = -EINVAL;
     97		break;
     98	}
     99
    100	return ret;
    101}
    102
    103static int __maybe_unused max517_suspend(struct device *dev)
    104{
    105	u8 outbuf = COMMAND_PD;
    106
    107	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
    108}
    109
    110static int __maybe_unused max517_resume(struct device *dev)
    111{
    112	u8 outbuf = 0;
    113
    114	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
    115}
    116
    117static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
    118
    119static const struct iio_info max517_info = {
    120	.read_raw = max517_read_raw,
    121	.write_raw = max517_write_raw,
    122};
    123
    124#define MAX517_CHANNEL(chan) {				\
    125	.type = IIO_VOLTAGE,				\
    126	.indexed = 1,					\
    127	.output = 1,					\
    128	.channel = (chan),				\
    129	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
    130	BIT(IIO_CHAN_INFO_SCALE),			\
    131}
    132
    133static const struct iio_chan_spec max517_channels[] = {
    134	MAX517_CHANNEL(0),
    135	MAX517_CHANNEL(1),
    136	MAX517_CHANNEL(2),
    137	MAX517_CHANNEL(3),
    138	MAX517_CHANNEL(4),
    139	MAX517_CHANNEL(5),
    140	MAX517_CHANNEL(6),
    141	MAX517_CHANNEL(7),
    142};
    143
    144static int max517_probe(struct i2c_client *client,
    145			const struct i2c_device_id *id)
    146{
    147	struct max517_data *data;
    148	struct iio_dev *indio_dev;
    149	struct max517_platform_data *platform_data = client->dev.platform_data;
    150	int chan;
    151
    152	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
    153	if (!indio_dev)
    154		return -ENOMEM;
    155	data = iio_priv(indio_dev);
    156	data->client = client;
    157
    158	switch (id->driver_data) {
    159	case ID_MAX521:
    160		indio_dev->num_channels = 8;
    161		break;
    162	case ID_MAX520:
    163		indio_dev->num_channels = 4;
    164		break;
    165	case ID_MAX519:
    166	case ID_MAX518:
    167		indio_dev->num_channels = 2;
    168		break;
    169	default:  /* single channel for MAX517 */
    170		indio_dev->num_channels = 1;
    171		break;
    172	}
    173	indio_dev->channels = max517_channels;
    174	indio_dev->modes = INDIO_DIRECT_MODE;
    175	indio_dev->info = &max517_info;
    176
    177	/*
    178	 * Reference voltage on MAX518 and default is 5V, else take vref_mv
    179	 * from platform_data
    180	 */
    181	for (chan = 0; chan < indio_dev->num_channels; chan++) {
    182		if (id->driver_data == ID_MAX518 || !platform_data)
    183			data->vref_mv[chan] = 5000; /* mV */
    184		else
    185			data->vref_mv[chan] = platform_data->vref_mv[chan];
    186	}
    187
    188	return devm_iio_device_register(&client->dev, indio_dev);
    189}
    190
    191static const struct i2c_device_id max517_id[] = {
    192	{ "max517", ID_MAX517 },
    193	{ "max518", ID_MAX518 },
    194	{ "max519", ID_MAX519 },
    195	{ "max520", ID_MAX520 },
    196	{ "max521", ID_MAX521 },
    197	{ }
    198};
    199MODULE_DEVICE_TABLE(i2c, max517_id);
    200
    201static struct i2c_driver max517_driver = {
    202	.driver = {
    203		.name	= MAX517_DRV_NAME,
    204		.pm	= &max517_pm_ops,
    205	},
    206	.probe		= max517_probe,
    207	.id_table	= max517_id,
    208};
    209module_i2c_driver(max517_driver);
    210
    211MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
    212MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
    213MODULE_LICENSE("GPL");