forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
193 lines
4.3 KiB
193 lines
4.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* Copyright (C) 2017 Sean Young <[email protected]> |
|
*/ |
|
|
|
#include <linux/kernel.h> |
|
#include <linux/module.h> |
|
#include <linux/gpio/consumer.h> |
|
#include <linux/delay.h> |
|
#include <linux/slab.h> |
|
#include <linux/of.h> |
|
#include <linux/platform_device.h> |
|
#include <media/rc-core.h> |
|
|
|
#define DRIVER_NAME "gpio-ir-tx" |
|
#define DEVICE_NAME "GPIO IR Bit Banging Transmitter" |
|
|
|
struct gpio_ir { |
|
struct gpio_desc *gpio; |
|
unsigned int carrier; |
|
unsigned int duty_cycle; |
|
}; |
|
|
|
static const struct of_device_id gpio_ir_tx_of_match[] = { |
|
{ .compatible = "gpio-ir-tx", }, |
|
{ }, |
|
}; |
|
MODULE_DEVICE_TABLE(of, gpio_ir_tx_of_match); |
|
|
|
static int gpio_ir_tx_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle) |
|
{ |
|
struct gpio_ir *gpio_ir = dev->priv; |
|
|
|
gpio_ir->duty_cycle = duty_cycle; |
|
|
|
return 0; |
|
} |
|
|
|
static int gpio_ir_tx_set_carrier(struct rc_dev *dev, u32 carrier) |
|
{ |
|
struct gpio_ir *gpio_ir = dev->priv; |
|
|
|
if (carrier > 500000) |
|
return -EINVAL; |
|
|
|
gpio_ir->carrier = carrier; |
|
|
|
return 0; |
|
} |
|
|
|
static void gpio_ir_tx_unmodulated(struct gpio_ir *gpio_ir, uint *txbuf, |
|
uint count) |
|
{ |
|
ktime_t edge; |
|
s32 delta; |
|
int i; |
|
|
|
local_irq_disable(); |
|
|
|
edge = ktime_get(); |
|
|
|
for (i = 0; i < count; i++) { |
|
gpiod_set_value(gpio_ir->gpio, !(i % 2)); |
|
|
|
edge = ktime_add_us(edge, txbuf[i]); |
|
delta = ktime_us_delta(edge, ktime_get()); |
|
if (delta > 0) |
|
udelay(delta); |
|
} |
|
|
|
gpiod_set_value(gpio_ir->gpio, 0); |
|
} |
|
|
|
static void gpio_ir_tx_modulated(struct gpio_ir *gpio_ir, uint *txbuf, |
|
uint count) |
|
{ |
|
ktime_t edge; |
|
/* |
|
* delta should never exceed 0.5 seconds (IR_MAX_DURATION) and on |
|
* m68k ndelay(s64) does not compile; so use s32 rather than s64. |
|
*/ |
|
s32 delta; |
|
int i; |
|
unsigned int pulse, space; |
|
|
|
/* Ensure the dividend fits into 32 bit */ |
|
pulse = DIV_ROUND_CLOSEST(gpio_ir->duty_cycle * (NSEC_PER_SEC / 100), |
|
gpio_ir->carrier); |
|
space = DIV_ROUND_CLOSEST((100 - gpio_ir->duty_cycle) * |
|
(NSEC_PER_SEC / 100), gpio_ir->carrier); |
|
|
|
local_irq_disable(); |
|
|
|
edge = ktime_get(); |
|
|
|
for (i = 0; i < count; i++) { |
|
if (i % 2) { |
|
// space |
|
edge = ktime_add_us(edge, txbuf[i]); |
|
delta = ktime_us_delta(edge, ktime_get()); |
|
if (delta > 0) |
|
udelay(delta); |
|
} else { |
|
// pulse |
|
ktime_t last = ktime_add_us(edge, txbuf[i]); |
|
|
|
while (ktime_before(ktime_get(), last)) { |
|
gpiod_set_value(gpio_ir->gpio, 1); |
|
edge = ktime_add_ns(edge, pulse); |
|
delta = ktime_to_ns(ktime_sub(edge, |
|
ktime_get())); |
|
if (delta > 0) |
|
ndelay(delta); |
|
gpiod_set_value(gpio_ir->gpio, 0); |
|
edge = ktime_add_ns(edge, space); |
|
delta = ktime_to_ns(ktime_sub(edge, |
|
ktime_get())); |
|
if (delta > 0) |
|
ndelay(delta); |
|
} |
|
|
|
edge = last; |
|
} |
|
} |
|
} |
|
|
|
static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf, |
|
unsigned int count) |
|
{ |
|
struct gpio_ir *gpio_ir = dev->priv; |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
if (gpio_ir->carrier) |
|
gpio_ir_tx_modulated(gpio_ir, txbuf, count); |
|
else |
|
gpio_ir_tx_unmodulated(gpio_ir, txbuf, count); |
|
local_irq_restore(flags); |
|
|
|
return count; |
|
} |
|
|
|
static int gpio_ir_tx_probe(struct platform_device *pdev) |
|
{ |
|
struct gpio_ir *gpio_ir; |
|
struct rc_dev *rcdev; |
|
int rc; |
|
|
|
gpio_ir = devm_kmalloc(&pdev->dev, sizeof(*gpio_ir), GFP_KERNEL); |
|
if (!gpio_ir) |
|
return -ENOMEM; |
|
|
|
rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX); |
|
if (!rcdev) |
|
return -ENOMEM; |
|
|
|
gpio_ir->gpio = devm_gpiod_get(&pdev->dev, NULL, GPIOD_OUT_LOW); |
|
if (IS_ERR(gpio_ir->gpio)) { |
|
if (PTR_ERR(gpio_ir->gpio) != -EPROBE_DEFER) |
|
dev_err(&pdev->dev, "Failed to get gpio (%ld)\n", |
|
PTR_ERR(gpio_ir->gpio)); |
|
return PTR_ERR(gpio_ir->gpio); |
|
} |
|
|
|
rcdev->priv = gpio_ir; |
|
rcdev->driver_name = DRIVER_NAME; |
|
rcdev->device_name = DEVICE_NAME; |
|
rcdev->tx_ir = gpio_ir_tx; |
|
rcdev->s_tx_duty_cycle = gpio_ir_tx_set_duty_cycle; |
|
rcdev->s_tx_carrier = gpio_ir_tx_set_carrier; |
|
|
|
gpio_ir->carrier = 38000; |
|
gpio_ir->duty_cycle = 50; |
|
|
|
rc = devm_rc_register_device(&pdev->dev, rcdev); |
|
if (rc < 0) |
|
dev_err(&pdev->dev, "failed to register rc device\n"); |
|
|
|
return rc; |
|
} |
|
|
|
static struct platform_driver gpio_ir_tx_driver = { |
|
.probe = gpio_ir_tx_probe, |
|
.driver = { |
|
.name = DRIVER_NAME, |
|
.of_match_table = of_match_ptr(gpio_ir_tx_of_match), |
|
}, |
|
}; |
|
module_platform_driver(gpio_ir_tx_driver); |
|
|
|
MODULE_DESCRIPTION("GPIO IR Bit Banging Transmitter"); |
|
MODULE_AUTHOR("Sean Young <[email protected]>"); |
|
MODULE_LICENSE("GPL");
|
|
|