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 int j; 61 u16 val = ((i + 1) % 2) ? idata->pulse : idata->space; 62 63 if (len + buffer[i] >= IR_SPI_MAX_BUFSIZE) 64 return -EINVAL; 65 66 /* 67 * the first value in buffer is a pulse, so that 0, 2, 4, ... 68 * contain a pulse duration. On the contrary, 1, 3, 5, ... 69 * contain a space duration. 70 */ 71 val = (i % 2) ? idata->space : idata->pulse; 72 for (j = 0; j < buffer[i]; j++) 73 idata->tx_buf[len++] = val; 74 } 75 76 memset(&xfer, 0, sizeof(xfer)); 77 78 xfer.speed_hz = idata->freq; 79 xfer.len = len * sizeof(*idata->tx_buf); 80 xfer.tx_buf = idata->tx_buf; 81 82 ret = regulator_enable(idata->regulator); 83 if (ret) 84 return ret; 85 86 ret = spi_sync_transfer(idata->spi, &xfer, 1); 87 if (ret) 88 dev_err(&idata->spi->dev, "unable to deliver the signal\n"); 89 90 regulator_disable(idata->regulator); 91 92 return ret ? ret : count; 93 } 94 95 static int ir_spi_set_tx_carrier(struct rc_dev *dev, u32 carrier) 96 { 97 struct ir_spi_data *idata = dev->priv; 98 99 if (!carrier) 100 return -EINVAL; 101 102 idata->freq = carrier; 103 104 return 0; 105 } 106 107 static int ir_spi_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle) 108 { 109 struct ir_spi_data *idata = dev->priv; 110 111 if (duty_cycle >= 90) 112 idata->pulse = IR_SPI_PULSE_DC_90; 113 else if (duty_cycle >= 80) 114 idata->pulse = IR_SPI_PULSE_DC_80; 115 else if (duty_cycle >= 75) 116 idata->pulse = IR_SPI_PULSE_DC_75; 117 else if (duty_cycle >= 70) 118 idata->pulse = IR_SPI_PULSE_DC_70; 119 else if (duty_cycle >= 60) 120 idata->pulse = IR_SPI_PULSE_DC_60; 121 else 122 idata->pulse = IR_SPI_PULSE_DC_50; 123 124 if (idata->negated) { 125 idata->pulse = ~idata->pulse; 126 idata->space = 0xffff; 127 } else { 128 idata->space = 0; 129 } 130 131 return 0; 132 } 133 134 static int ir_spi_probe(struct spi_device *spi) 135 { 136 int ret; 137 u8 dc; 138 struct ir_spi_data *idata; 139 140 idata = devm_kzalloc(&spi->dev, sizeof(*idata), GFP_KERNEL); 141 if (!idata) 142 return -ENOMEM; 143 144 idata->regulator = devm_regulator_get(&spi->dev, "irda_regulator"); 145 if (IS_ERR(idata->regulator)) 146 return PTR_ERR(idata->regulator); 147 148 idata->rc = devm_rc_allocate_device(&spi->dev, RC_DRIVER_IR_RAW_TX); 149 if (!idata->rc) 150 return -ENOMEM; 151 152 idata->rc->tx_ir = ir_spi_tx; 153 idata->rc->s_tx_carrier = ir_spi_set_tx_carrier; 154 idata->rc->s_tx_duty_cycle = ir_spi_set_duty_cycle; 155 idata->rc->driver_name = IR_SPI_DRIVER_NAME; 156 idata->rc->priv = idata; 157 idata->spi = spi; 158 159 idata->negated = of_property_read_bool(spi->dev.of_node, 160 "led-active-low"); 161 ret = of_property_read_u8(spi->dev.of_node, "duty-cycle", &dc); 162 if (ret) 163 dc = 50; 164 165 /* ir_spi_set_duty_cycle cannot fail, 166 * it returns int to be compatible with the 167 * rc->s_tx_duty_cycle function 168 */ 169 ir_spi_set_duty_cycle(idata->rc, dc); 170 171 idata->freq = IR_SPI_DEFAULT_FREQUENCY; 172 173 return devm_rc_register_device(&spi->dev, idata->rc); 174 } 175 176 static int ir_spi_remove(struct spi_device *spi) 177 { 178 return 0; 179 } 180 181 static const struct of_device_id ir_spi_of_match[] = { 182 { .compatible = "ir-spi-led" }, 183 {}, 184 }; 185 186 static struct spi_driver ir_spi_driver = { 187 .probe = ir_spi_probe, 188 .remove = ir_spi_remove, 189 .driver = { 190 .name = IR_SPI_DRIVER_NAME, 191 .of_match_table = ir_spi_of_match, 192 }, 193 }; 194 195 module_spi_driver(ir_spi_driver); 196 197 MODULE_AUTHOR("Andi Shyti <andi.shyti@samsung.com>"); 198 MODULE_DESCRIPTION("SPI IR LED"); 199 MODULE_LICENSE("GPL v2"); 200