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