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179 lines
3.9 KiB
179 lines
3.9 KiB
// 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 <[email protected]> |
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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 int ir_spi_remove(struct spi_device *spi) |
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{ |
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return 0; |
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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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.remove = ir_spi_remove, |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("SPI IR LED"); |
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MODULE_LICENSE("GPL v2");
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