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 }; 189 190 static struct spi_driver ir_spi_driver = { 191 .probe = ir_spi_probe, 192 .remove = ir_spi_remove, 193 .driver = { 194 .name = IR_SPI_DRIVER_NAME, 195 .of_match_table = ir_spi_of_match, 196 }, 197 }; 198 199 module_spi_driver(ir_spi_driver); 200 201 MODULE_AUTHOR("Andi Shyti <andi.shyti@samsung.com>"); 202 MODULE_DESCRIPTION("SPI IR LED"); 203 MODULE_LICENSE("GPL v2"); 204