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