diff options
Diffstat (limited to 'drivers/media/rc/ir-spi.c')
| -rw-r--r-- | drivers/media/rc/ir-spi.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-spi.c b/drivers/media/rc/ir-spi.c new file mode 100644 index 000000000000..392441e0c116 --- /dev/null +++ b/drivers/media/rc/ir-spi.c @@ -0,0 +1,195 @@ +// 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/bits.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/math.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/property.h> +#include <linux/regulator/consumer.h> +#include <linux/spi/spi.h> +#include <linux/string.h> +#include <linux/types.h> + +#include <media/rc-core.h> + +#define IR_SPI_DRIVER_NAME "ir-spi" + +#define IR_SPI_DEFAULT_FREQUENCY 38000 +#define IR_SPI_BITS_PER_PULSE 16 + +struct ir_spi_data { + u32 freq; + bool negated; + + 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; + u16 *tx_buf; + + /* convert the pulse/space signal to raw binary signal */ + for (i = 0; i < count; i++) { + buffer[i] = DIV_ROUND_CLOSEST_ULL((u64)buffer[i] * idata->freq, + 1000000); + len += buffer[i]; + } + + tx_buf = kmalloc_array(len, sizeof(*tx_buf), GFP_KERNEL); + if (!tx_buf) + return -ENOMEM; + + len = 0; + for (i = 0; i < count; i++) { + int j; + u16 val; + + /* + * 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 < buffer[i]; j++) + tx_buf[len++] = val; + } + + memset(&xfer, 0, sizeof(xfer)); + + xfer.speed_hz = idata->freq * IR_SPI_BITS_PER_PULSE; + xfer.len = len * sizeof(*tx_buf); + xfer.tx_buf = tx_buf; + + ret = regulator_enable(idata->regulator); + if (ret) + goto err_free_tx_buf; + + 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); + +err_free_tx_buf: + + kfree(tx_buf); + + 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; + + if (carrier > idata->spi->max_speed_hz / IR_SPI_BITS_PER_PULSE) + 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) +{ + struct device *dev = &spi->dev; + int ret; + u8 dc; + struct ir_spi_data *idata; + + idata = devm_kzalloc(dev, sizeof(*idata), GFP_KERNEL); + if (!idata) + return -ENOMEM; + + idata->regulator = devm_regulator_get(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 = device_property_read_bool(dev, "led-active-low"); + ret = device_property_read_u8(dev, "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(dev, idata->rc); +} + +static const struct of_device_id ir_spi_of_match[] = { + { .compatible = "ir-spi-led" }, + {} +}; +MODULE_DEVICE_TABLE(of, ir_spi_of_match); + +static const struct spi_device_id ir_spi_ids[] = { + { "ir-spi-led" }, + {} +}; +MODULE_DEVICE_TABLE(spi, ir_spi_ids); + +static struct spi_driver ir_spi_driver = { + .probe = ir_spi_probe, + .id_table = ir_spi_ids, + .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"); |