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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ir-spi.c (3943B)

      1// SPDX-License-Identifier: GPL-2.0
      2// SPI driven IR LED device driver
      3//
      4// Copyright (c) 2016 Samsung Electronics Co., Ltd.
      5// Copyright (c) Andi Shyti <andi@etezian.org>
      6
      7#include <linux/delay.h>
      8#include <linux/fs.h>
      9#include <linux/module.h>
     10#include <linux/mutex.h>
     11#include <linux/of_gpio.h>
     12#include <linux/regulator/consumer.h>
     13#include <linux/spi/spi.h>
     14#include <media/rc-core.h>
     15
     16#define IR_SPI_DRIVER_NAME		"ir-spi"
     17
     18#define IR_SPI_DEFAULT_FREQUENCY	38000
     19#define IR_SPI_MAX_BUFSIZE		 4096
     20
     21struct ir_spi_data {
     22	u32 freq;
     23	bool negated;
     24
     25	u16 tx_buf[IR_SPI_MAX_BUFSIZE];
     26	u16 pulse;
     27	u16 space;
     28
     29	struct rc_dev *rc;
     30	struct spi_device *spi;
     31	struct regulator *regulator;
     32};
     33
     34static int ir_spi_tx(struct rc_dev *dev,
     35		     unsigned int *buffer, unsigned int count)
     36{
     37	int i;
     38	int ret;
     39	unsigned int len = 0;
     40	struct ir_spi_data *idata = dev->priv;
     41	struct spi_transfer xfer;
     42
     43	/* convert the pulse/space signal to raw binary signal */
     44	for (i = 0; i < count; i++) {
     45		unsigned int periods;
     46		int j;
     47		u16 val;
     48
     49		periods = DIV_ROUND_CLOSEST(buffer[i] * idata->freq, 1000000);
     50
     51		if (len + periods >= IR_SPI_MAX_BUFSIZE)
     52			return -EINVAL;
     53
     54		/*
     55		 * the first value in buffer is a pulse, so that 0, 2, 4, ...
     56		 * contain a pulse duration. On the contrary, 1, 3, 5, ...
     57		 * contain a space duration.
     58		 */
     59		val = (i % 2) ? idata->space : idata->pulse;
     60		for (j = 0; j < periods; j++)
     61			idata->tx_buf[len++] = val;
     62	}
     63
     64	memset(&xfer, 0, sizeof(xfer));
     65
     66	xfer.speed_hz = idata->freq * 16;
     67	xfer.len = len * sizeof(*idata->tx_buf);
     68	xfer.tx_buf = idata->tx_buf;
     69
     70	ret = regulator_enable(idata->regulator);
     71	if (ret)
     72		return ret;
     73
     74	ret = spi_sync_transfer(idata->spi, &xfer, 1);
     75	if (ret)
     76		dev_err(&idata->spi->dev, "unable to deliver the signal\n");
     77
     78	regulator_disable(idata->regulator);
     79
     80	return ret ? ret : count;
     81}
     82
     83static int ir_spi_set_tx_carrier(struct rc_dev *dev, u32 carrier)
     84{
     85	struct ir_spi_data *idata = dev->priv;
     86
     87	if (!carrier)
     88		return -EINVAL;
     89
     90	idata->freq = carrier;
     91
     92	return 0;
     93}
     94
     95static int ir_spi_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
     96{
     97	struct ir_spi_data *idata = dev->priv;
     98	int bits = (duty_cycle * 15) / 100;
     99
    100	idata->pulse = GENMASK(bits, 0);
    101
    102	if (idata->negated) {
    103		idata->pulse = ~idata->pulse;
    104		idata->space = 0xffff;
    105	} else {
    106		idata->space = 0;
    107	}
    108
    109	return 0;
    110}
    111
    112static int ir_spi_probe(struct spi_device *spi)
    113{
    114	int ret;
    115	u8 dc;
    116	struct ir_spi_data *idata;
    117
    118	idata = devm_kzalloc(&spi->dev, sizeof(*idata), GFP_KERNEL);
    119	if (!idata)
    120		return -ENOMEM;
    121
    122	idata->regulator = devm_regulator_get(&spi->dev, "irda_regulator");
    123	if (IS_ERR(idata->regulator))
    124		return PTR_ERR(idata->regulator);
    125
    126	idata->rc = devm_rc_allocate_device(&spi->dev, RC_DRIVER_IR_RAW_TX);
    127	if (!idata->rc)
    128		return -ENOMEM;
    129
    130	idata->rc->tx_ir           = ir_spi_tx;
    131	idata->rc->s_tx_carrier    = ir_spi_set_tx_carrier;
    132	idata->rc->s_tx_duty_cycle = ir_spi_set_duty_cycle;
    133	idata->rc->device_name	   = "IR SPI";
    134	idata->rc->driver_name     = IR_SPI_DRIVER_NAME;
    135	idata->rc->priv            = idata;
    136	idata->spi                 = spi;
    137
    138	idata->negated = of_property_read_bool(spi->dev.of_node,
    139							"led-active-low");
    140	ret = of_property_read_u8(spi->dev.of_node, "duty-cycle", &dc);
    141	if (ret)
    142		dc = 50;
    143
    144	/* ir_spi_set_duty_cycle cannot fail,
    145	 * it returns int to be compatible with the
    146	 * rc->s_tx_duty_cycle function
    147	 */
    148	ir_spi_set_duty_cycle(idata->rc, dc);
    149
    150	idata->freq = IR_SPI_DEFAULT_FREQUENCY;
    151
    152	return devm_rc_register_device(&spi->dev, idata->rc);
    153}
    154
    155static const struct of_device_id ir_spi_of_match[] = {
    156	{ .compatible = "ir-spi-led" },
    157	{},
    158};
    159MODULE_DEVICE_TABLE(of, ir_spi_of_match);
    160
    161static struct spi_driver ir_spi_driver = {
    162	.probe = ir_spi_probe,
    163	.driver = {
    164		.name = IR_SPI_DRIVER_NAME,
    165		.of_match_table = ir_spi_of_match,
    166	},
    167};
    168
    169module_spi_driver(ir_spi_driver);
    170
    171MODULE_AUTHOR("Andi Shyti <andi@etezian.org>");
    172MODULE_DESCRIPTION("SPI IR LED");
    173MODULE_LICENSE("GPL v2");