174 lines
3.9 KiB
C
174 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// SPI driven IR LED device driver
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//
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// Copyright (c) 2016 Samsung Electronics Co., Ltd.
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// Copyright (c) Andi Shyti <andi@etezian.org>
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#include <linux/delay.h>
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of_gpio.h>
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#include <linux/regulator/consumer.h>
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#include <linux/spi/spi.h>
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#include <media/rc-core.h>
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#define IR_SPI_DRIVER_NAME "ir-spi"
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#define IR_SPI_DEFAULT_FREQUENCY 38000
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#define IR_SPI_MAX_BUFSIZE 4096
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struct ir_spi_data {
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u32 freq;
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bool negated;
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u16 tx_buf[IR_SPI_MAX_BUFSIZE];
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u16 pulse;
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u16 space;
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struct rc_dev *rc;
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struct spi_device *spi;
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struct regulator *regulator;
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};
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static int ir_spi_tx(struct rc_dev *dev,
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unsigned int *buffer, unsigned int count)
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{
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int i;
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int ret;
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unsigned int len = 0;
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struct ir_spi_data *idata = dev->priv;
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struct spi_transfer xfer;
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/* convert the pulse/space signal to raw binary signal */
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for (i = 0; i < count; i++) {
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unsigned int periods;
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int j;
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u16 val;
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periods = DIV_ROUND_CLOSEST(buffer[i] * idata->freq, 1000000);
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if (len + periods >= IR_SPI_MAX_BUFSIZE)
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return -EINVAL;
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/*
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* the first value in buffer is a pulse, so that 0, 2, 4, ...
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* contain a pulse duration. On the contrary, 1, 3, 5, ...
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* contain a space duration.
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*/
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val = (i % 2) ? idata->space : idata->pulse;
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for (j = 0; j < periods; j++)
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idata->tx_buf[len++] = val;
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}
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memset(&xfer, 0, sizeof(xfer));
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xfer.speed_hz = idata->freq * 16;
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xfer.len = len * sizeof(*idata->tx_buf);
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xfer.tx_buf = idata->tx_buf;
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ret = regulator_enable(idata->regulator);
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if (ret)
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return ret;
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ret = spi_sync_transfer(idata->spi, &xfer, 1);
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if (ret)
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dev_err(&idata->spi->dev, "unable to deliver the signal\n");
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regulator_disable(idata->regulator);
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return ret ? ret : count;
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}
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static int ir_spi_set_tx_carrier(struct rc_dev *dev, u32 carrier)
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{
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struct ir_spi_data *idata = dev->priv;
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if (!carrier)
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return -EINVAL;
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idata->freq = carrier;
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return 0;
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}
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static int ir_spi_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
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{
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struct ir_spi_data *idata = dev->priv;
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int bits = (duty_cycle * 15) / 100;
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idata->pulse = GENMASK(bits, 0);
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if (idata->negated) {
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idata->pulse = ~idata->pulse;
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idata->space = 0xffff;
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} else {
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idata->space = 0;
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}
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return 0;
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}
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static int ir_spi_probe(struct spi_device *spi)
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{
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int ret;
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u8 dc;
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struct ir_spi_data *idata;
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idata = devm_kzalloc(&spi->dev, sizeof(*idata), GFP_KERNEL);
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if (!idata)
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return -ENOMEM;
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idata->regulator = devm_regulator_get(&spi->dev, "irda_regulator");
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if (IS_ERR(idata->regulator))
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return PTR_ERR(idata->regulator);
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idata->rc = devm_rc_allocate_device(&spi->dev, RC_DRIVER_IR_RAW_TX);
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if (!idata->rc)
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return -ENOMEM;
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idata->rc->tx_ir = ir_spi_tx;
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idata->rc->s_tx_carrier = ir_spi_set_tx_carrier;
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idata->rc->s_tx_duty_cycle = ir_spi_set_duty_cycle;
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idata->rc->device_name = "IR SPI";
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idata->rc->driver_name = IR_SPI_DRIVER_NAME;
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idata->rc->priv = idata;
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idata->spi = spi;
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idata->negated = of_property_read_bool(spi->dev.of_node,
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"led-active-low");
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ret = of_property_read_u8(spi->dev.of_node, "duty-cycle", &dc);
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if (ret)
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dc = 50;
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/* ir_spi_set_duty_cycle cannot fail,
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* it returns int to be compatible with the
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* rc->s_tx_duty_cycle function
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*/
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ir_spi_set_duty_cycle(idata->rc, dc);
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idata->freq = IR_SPI_DEFAULT_FREQUENCY;
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return devm_rc_register_device(&spi->dev, idata->rc);
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}
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static const struct of_device_id ir_spi_of_match[] = {
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{ .compatible = "ir-spi-led" },
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{},
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};
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MODULE_DEVICE_TABLE(of, ir_spi_of_match);
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static struct spi_driver ir_spi_driver = {
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.probe = ir_spi_probe,
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.driver = {
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.name = IR_SPI_DRIVER_NAME,
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.of_match_table = ir_spi_of_match,
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},
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};
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module_spi_driver(ir_spi_driver);
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MODULE_AUTHOR("Andi Shyti <andi@etezian.org>");
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MODULE_DESCRIPTION("SPI IR LED");
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MODULE_LICENSE("GPL v2");
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