LXR linux/drivers/media/rc/ir-spi.c

   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 int ir_spi_remove(struct spi_device *spi)
 156{
 157        return 0;
 158}
 159
 160static const struct of_device_id ir_spi_of_match[] = {
 161        { .compatible = "ir-spi-led" },
 162        {},
 163};
 164MODULE_DEVICE_TABLE(of, ir_spi_of_match);
 165
 166static struct spi_driver ir_spi_driver = {
 167        .probe = ir_spi_probe,
 168        .remove = ir_spi_remove,
 169        .driver = {
 170                .name = IR_SPI_DRIVER_NAME,
 171                .of_match_table = ir_spi_of_match,
 172        },
 173};
 174
 175module_spi_driver(ir_spi_driver);
 176
 177MODULE_AUTHOR("Andi Shyti <andi@etezian.org>");
 178MODULE_DESCRIPTION("SPI IR LED");
 179MODULE_LICENSE("GPL v2");
 180