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 21 struct 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 34 static 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 83 static 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 95 static 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 } 111 112 static 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 } 154 155 static int ir_spi_remove(struct spi_device *spi) 156 { 157 return 0; 158 } 159 160 static const struct of_device_id ir_spi_of_match[] = { 161 { .compatible = "ir-spi-led" }, 162 {}, 163 }; 164 MODULE_DEVICE_TABLE(of, ir_spi_of_match); 165 166 static 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 }; 174 175 module_spi_driver(ir_spi_driver); 176 177 MODULE_AUTHOR("Andi Shyti <andi@etezian.org>"); 178 MODULE_DESCRIPTION("SPI IR LED"); 179 MODULE_LICENSE("GPL v2"); 180