drivers/media/rc/ir-spi.c

   1 /*
   2  * Copyright (c) 2016 Samsung Electronics Co., Ltd.
   3  * Author: Andi Shyti <andi.shyti@samsung.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * SPI driven IR LED device driver
  10  */
  11
  12 #include <linux/delay.h>
  13 #include <linux/fs.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/of_gpio.h>
  17 #include <linux/regulator/consumer.h>
  18 #include <linux/spi/spi.h>
  19 #include <media/rc-core.h>
  20
  21 #define IR_SPI_DRIVER_NAME              "ir-spi"
  22
  23 /* pulse value for different duty cycles */
  24 #define IR_SPI_PULSE_DC_50              0xff00
  25 #define IR_SPI_PULSE_DC_60              0xfc00
  26 #define IR_SPI_PULSE_DC_70              0xf800
  27 #define IR_SPI_PULSE_DC_75              0xf000
  28 #define IR_SPI_PULSE_DC_80              0xc000
  29 #define IR_SPI_PULSE_DC_90              0x8000
  30
  31 #define IR_SPI_DEFAULT_FREQUENCY        38000
  32 #define IR_SPI_BIT_PER_WORD                 8
  33 #define IR_SPI_MAX_BUFSIZE               4096
  34
  35 struct ir_spi_data {
  36         u32 freq;
  37         u8 duty_cycle;
  38         bool negated;
  39
  40         u16 tx_buf[IR_SPI_MAX_BUFSIZE];
  41         u16 pulse;
  42         u16 space;
  43
  44         struct rc_dev *rc;
  45         struct spi_device *spi;
  46         struct regulator *regulator;
  47 };
  48
  49 static int ir_spi_tx(struct rc_dev *dev,
  50                      unsigned int *buffer, unsigned int count)
  51 {
  52         int i;
  53         int ret;
  54         unsigned int len = 0;
  55         struct ir_spi_data *idata = dev->priv;
  56         struct spi_transfer xfer;
  57
  58         /* convert the pulse/space signal to raw binary signal */
  59         for (i = 0; i < count; i++) {
  60                 unsigned int periods;
  61                 int j;
  62                 u16 val;
  63
  64                 periods = DIV_ROUND_CLOSEST(buffer[i] * idata->freq, 1000000);
  65
  66                 if (len + periods >= IR_SPI_MAX_BUFSIZE)
  67                         return -EINVAL;
  68
  69                 /*
  70                  * the first value in buffer is a pulse, so that 0, 2, 4, ...
  71                  * contain a pulse duration. On the contrary, 1, 3, 5, ...
  72                  * contain a space duration.
  73                  */
  74                 val = (i % 2) ? idata->space : idata->pulse;
  75                 for (j = 0; j < periods; j++)
  76                         idata->tx_buf[len++] = val;
  77         }
  78
  79         memset(&xfer, 0, sizeof(xfer));
  80
  81         xfer.speed_hz = idata->freq * 16;
  82         xfer.len = len * sizeof(*idata->tx_buf);
  83         xfer.tx_buf = idata->tx_buf;
  84
  85         ret = regulator_enable(idata->regulator);
  86         if (ret)
  87                 return ret;
  88
  89         ret = spi_sync_transfer(idata->spi, &xfer, 1);
  90         if (ret)
  91                 dev_err(&idata->spi->dev, "unable to deliver the signal\n");
  92
  93         regulator_disable(idata->regulator);
  94
  95         return ret ? ret : count;
  96 }
  97
  98 static int ir_spi_set_tx_carrier(struct rc_dev *dev, u32 carrier)
  99 {
 100         struct ir_spi_data *idata = dev->priv;
 101
 102         if (!carrier)
 103                 return -EINVAL;
 104
 105         idata->freq = carrier;
 106
 107         return 0;
 108 }
 109
 110 static int ir_spi_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
 111 {
 112         struct ir_spi_data *idata = dev->priv;
 113
 114         if (duty_cycle >= 90)
 115                 idata->pulse = IR_SPI_PULSE_DC_90;
 116         else if (duty_cycle >= 80)
 117                 idata->pulse = IR_SPI_PULSE_DC_80;
 118         else if (duty_cycle >= 75)
 119                 idata->pulse = IR_SPI_PULSE_DC_75;
 120         else if (duty_cycle >= 70)
 121                 idata->pulse = IR_SPI_PULSE_DC_70;
 122         else if (duty_cycle >= 60)
 123                 idata->pulse = IR_SPI_PULSE_DC_60;
 124         else
 125                 idata->pulse = IR_SPI_PULSE_DC_50;
 126
 127         if (idata->negated) {
 128                 idata->pulse = ~idata->pulse;
 129                 idata->space = 0xffff;
 130         } else {
 131                 idata->space = 0;
 132         }
 133
 134         return 0;
 135 }
 136
 137 static int ir_spi_probe(struct spi_device *spi)
 138 {
 139         int ret;
 140         u8 dc;
 141         struct ir_spi_data *idata;
 142
 143         idata = devm_kzalloc(&spi->dev, sizeof(*idata), GFP_KERNEL);
 144         if (!idata)
 145                 return -ENOMEM;
 146
 147         idata->regulator = devm_regulator_get(&spi->dev, "irda_regulator");
 148         if (IS_ERR(idata->regulator))
 149                 return PTR_ERR(idata->regulator);
 150
 151         idata->rc = devm_rc_allocate_device(&spi->dev, RC_DRIVER_IR_RAW_TX);
 152         if (!idata->rc)
 153                 return -ENOMEM;
 154
 155         idata->rc->tx_ir           = ir_spi_tx;
 156         idata->rc->s_tx_carrier    = ir_spi_set_tx_carrier;
 157         idata->rc->s_tx_duty_cycle = ir_spi_set_duty_cycle;
 158         idata->rc->device_name     = "IR SPI";
 159         idata->rc->driver_name     = IR_SPI_DRIVER_NAME;
 160         idata->rc->priv            = idata;
 161         idata->spi                 = spi;
 162
 163         idata->negated = of_property_read_bool(spi->dev.of_node,
 164                                                         "led-active-low");
 165         ret = of_property_read_u8(spi->dev.of_node, "duty-cycle", &dc);
 166         if (ret)
 167                 dc = 50;
 168
 169         /* ir_spi_set_duty_cycle cannot fail,
 170          * it returns int to be compatible with the
 171          * rc->s_tx_duty_cycle function
 172          */
 173         ir_spi_set_duty_cycle(idata->rc, dc);
 174
 175         idata->freq = IR_SPI_DEFAULT_FREQUENCY;
 176
 177         return devm_rc_register_device(&spi->dev, idata->rc);
 178 }
 179
 180 static int ir_spi_remove(struct spi_device *spi)
 181 {
 182         return 0;
 183 }
 184
 185 static const struct of_device_id ir_spi_of_match[] = {
 186         { .compatible = "ir-spi-led" },
 187         {},
 188 };
 189 MODULE_DEVICE_TABLE(of, ir_spi_of_match);
 190
 191 static struct spi_driver ir_spi_driver = {
 192         .probe = ir_spi_probe,
 193         .remove = ir_spi_remove,
 194         .driver = {
 195                 .name = IR_SPI_DRIVER_NAME,
 196                 .of_match_table = ir_spi_of_match,
 197         },
 198 };
 199
 200 module_spi_driver(ir_spi_driver);
 201
 202 MODULE_AUTHOR("Andi Shyti <andi.shyti@samsung.com>");
 203 MODULE_DESCRIPTION("SPI IR LED");
 204 MODULE_LICENSE("GPL v2");