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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ltc1660.c (6177B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC
      4 *
      5 * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
      6 */
      7#include <linux/bitops.h>
      8#include <linux/iio/iio.h>
      9#include <linux/iio/sysfs.h>
     10#include <linux/init.h>
     11#include <linux/module.h>
     12#include <linux/regulator/consumer.h>
     13#include <linux/regmap.h>
     14#include <linux/spi/spi.h>
     15
     16#define LTC1660_REG_WAKE	0x0
     17#define LTC1660_REG_DAC_A	0x1
     18#define LTC1660_REG_DAC_B	0x2
     19#define LTC1660_REG_DAC_C	0x3
     20#define LTC1660_REG_DAC_D	0x4
     21#define LTC1660_REG_DAC_E	0x5
     22#define LTC1660_REG_DAC_F	0x6
     23#define LTC1660_REG_DAC_G	0x7
     24#define LTC1660_REG_DAC_H	0x8
     25#define LTC1660_REG_SLEEP	0xe
     26
     27#define LTC1660_NUM_CHANNELS	8
     28
     29static const struct regmap_config ltc1660_regmap_config = {
     30	.reg_bits = 4,
     31	.val_bits = 12,
     32};
     33
     34enum ltc1660_supported_device_ids {
     35	ID_LTC1660,
     36	ID_LTC1665,
     37};
     38
     39struct ltc1660_priv {
     40	struct spi_device *spi;
     41	struct regmap *regmap;
     42	struct regulator *vref_reg;
     43	unsigned int value[LTC1660_NUM_CHANNELS];
     44	unsigned int vref_mv;
     45};
     46
     47static int ltc1660_read_raw(struct iio_dev *indio_dev,
     48		struct iio_chan_spec const *chan,
     49		int *val,
     50		int *val2,
     51		long mask)
     52{
     53	struct ltc1660_priv *priv = iio_priv(indio_dev);
     54
     55	switch (mask) {
     56	case IIO_CHAN_INFO_RAW:
     57		*val = priv->value[chan->channel];
     58		return IIO_VAL_INT;
     59	case IIO_CHAN_INFO_SCALE:
     60		*val = regulator_get_voltage(priv->vref_reg);
     61		if (*val < 0) {
     62			dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n",
     63					*val);
     64			return *val;
     65		}
     66
     67		/* Convert to mV */
     68		*val /= 1000;
     69		*val2 = chan->scan_type.realbits;
     70		return IIO_VAL_FRACTIONAL_LOG2;
     71	default:
     72		return -EINVAL;
     73	}
     74}
     75
     76static int ltc1660_write_raw(struct iio_dev *indio_dev,
     77		struct iio_chan_spec const *chan,
     78		int val,
     79		int val2,
     80		long mask)
     81{
     82	struct ltc1660_priv *priv = iio_priv(indio_dev);
     83	int ret;
     84
     85	switch (mask) {
     86	case IIO_CHAN_INFO_RAW:
     87		if (val2 != 0)
     88			return -EINVAL;
     89
     90		if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
     91			return -EINVAL;
     92
     93		ret = regmap_write(priv->regmap, chan->channel,
     94					(val << chan->scan_type.shift));
     95		if (!ret)
     96			priv->value[chan->channel] = val;
     97
     98		return ret;
     99	default:
    100		return -EINVAL;
    101	}
    102}
    103
    104#define LTC1660_CHAN(chan, bits) {			\
    105	.type = IIO_VOLTAGE,				\
    106	.indexed = 1,					\
    107	.output = 1,					\
    108	.channel = chan,				\
    109	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
    110	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
    111	.scan_type = {					\
    112		.sign = 'u',				\
    113		.realbits = (bits),			\
    114		.storagebits = 16,			\
    115		.shift = 12 - (bits),			\
    116	},						\
    117}
    118
    119#define  LTC1660_OCTAL_CHANNELS(bits) {			\
    120		LTC1660_CHAN(LTC1660_REG_DAC_A, bits),	\
    121		LTC1660_CHAN(LTC1660_REG_DAC_B, bits),	\
    122		LTC1660_CHAN(LTC1660_REG_DAC_C, bits),	\
    123		LTC1660_CHAN(LTC1660_REG_DAC_D, bits),	\
    124		LTC1660_CHAN(LTC1660_REG_DAC_E, bits),	\
    125		LTC1660_CHAN(LTC1660_REG_DAC_F, bits),	\
    126		LTC1660_CHAN(LTC1660_REG_DAC_G, bits),	\
    127		LTC1660_CHAN(LTC1660_REG_DAC_H, bits),	\
    128}
    129
    130static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = {
    131	[ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10),
    132	[ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8),
    133};
    134
    135static const struct iio_info ltc1660_info = {
    136	.read_raw = &ltc1660_read_raw,
    137	.write_raw = &ltc1660_write_raw,
    138};
    139
    140static int __maybe_unused ltc1660_suspend(struct device *dev)
    141{
    142	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
    143						to_spi_device(dev)));
    144	return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00);
    145}
    146
    147static int __maybe_unused ltc1660_resume(struct device *dev)
    148{
    149	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
    150						to_spi_device(dev)));
    151	return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00);
    152}
    153static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume);
    154
    155static int ltc1660_probe(struct spi_device *spi)
    156{
    157	struct iio_dev *indio_dev;
    158	struct ltc1660_priv *priv;
    159	const struct spi_device_id *id = spi_get_device_id(spi);
    160	int ret;
    161
    162	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
    163	if (indio_dev == NULL)
    164		return -ENOMEM;
    165
    166	priv = iio_priv(indio_dev);
    167	priv->regmap = devm_regmap_init_spi(spi, &ltc1660_regmap_config);
    168	if (IS_ERR(priv->regmap)) {
    169		dev_err(&spi->dev, "failed to register spi regmap %ld\n",
    170			PTR_ERR(priv->regmap));
    171		return PTR_ERR(priv->regmap);
    172	}
    173
    174	priv->vref_reg = devm_regulator_get(&spi->dev, "vref");
    175	if (IS_ERR(priv->vref_reg))
    176		return dev_err_probe(&spi->dev, PTR_ERR(priv->vref_reg),
    177				     "vref regulator not specified\n");
    178
    179	ret = regulator_enable(priv->vref_reg);
    180	if (ret) {
    181		dev_err(&spi->dev, "failed to enable vref regulator: %d\n",
    182				ret);
    183		return ret;
    184	}
    185
    186	priv->spi = spi;
    187	spi_set_drvdata(spi, indio_dev);
    188	indio_dev->info = &ltc1660_info;
    189	indio_dev->modes = INDIO_DIRECT_MODE;
    190	indio_dev->channels = ltc1660_channels[id->driver_data];
    191	indio_dev->num_channels = LTC1660_NUM_CHANNELS;
    192	indio_dev->name = id->name;
    193
    194	ret = iio_device_register(indio_dev);
    195	if (ret) {
    196		dev_err(&spi->dev, "failed to register iio device: %d\n",
    197				ret);
    198		goto error_disable_reg;
    199	}
    200
    201	return 0;
    202
    203error_disable_reg:
    204	regulator_disable(priv->vref_reg);
    205
    206	return ret;
    207}
    208
    209static void ltc1660_remove(struct spi_device *spi)
    210{
    211	struct iio_dev *indio_dev = spi_get_drvdata(spi);
    212	struct ltc1660_priv *priv = iio_priv(indio_dev);
    213
    214	iio_device_unregister(indio_dev);
    215	regulator_disable(priv->vref_reg);
    216}
    217
    218static const struct of_device_id ltc1660_dt_ids[] = {
    219	{ .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
    220	{ .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
    221	{ /* sentinel */ }
    222};
    223MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
    224
    225static const struct spi_device_id ltc1660_id[] = {
    226	{"ltc1660", ID_LTC1660},
    227	{"ltc1665", ID_LTC1665},
    228	{ /* sentinel */ }
    229};
    230MODULE_DEVICE_TABLE(spi, ltc1660_id);
    231
    232static struct spi_driver ltc1660_driver = {
    233	.driver = {
    234		.name = "ltc1660",
    235		.of_match_table = ltc1660_dt_ids,
    236		.pm = &ltc1660_pm_ops,
    237	},
    238	.probe	= ltc1660_probe,
    239	.remove = ltc1660_remove,
    240	.id_table = ltc1660_id,
    241};
    242module_spi_driver(ltc1660_driver);
    243
    244MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
    245MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
    246MODULE_LICENSE("GPL v2");