img-ir-raw.c
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/*
* ImgTec IR Raw Decoder found in PowerDown Controller.
*
* Copyright 2010-2014 Imagination Technologies Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This ties into the input subsystem using the RC-core in raw mode. Raw IR
* signal edges are reported and decoded by generic software decoders.
*/
#include <linux/spinlock.h>
#include <media/rc-core.h>
#include "img-ir.h"
#define ECHO_TIMEOUT_MS 150 /* ms between echos */
/* must be called with priv->lock held */
static void img_ir_refresh_raw(struct img_ir_priv *priv, u32 irq_status)
{
struct img_ir_priv_raw *raw = &priv->raw;
struct rc_dev *rc_dev = priv->raw.rdev;
int multiple;
u32 ir_status;
/* find whether both rise and fall was detected */
multiple = ((irq_status & IMG_IR_IRQ_EDGE) == IMG_IR_IRQ_EDGE);
/*
* If so, we need to see if the level has actually changed.
* If it's just noise that we didn't have time to process,
* there's no point reporting it.
*/
ir_status = img_ir_read(priv, IMG_IR_STATUS) & IMG_IR_IRRXD;
if (multiple && ir_status == raw->last_status)
return;
raw->last_status = ir_status;
/* report the edge to the IR raw decoders */
if (ir_status) /* low */
ir_raw_event_store_edge(rc_dev, IR_SPACE);
else /* high */
ir_raw_event_store_edge(rc_dev, IR_PULSE);
ir_raw_event_handle(rc_dev);
}
/* called with priv->lock held */
void img_ir_isr_raw(struct img_ir_priv *priv, u32 irq_status)
{
struct img_ir_priv_raw *raw = &priv->raw;
/* check not removing */
if (!raw->rdev)
return;
img_ir_refresh_raw(priv, irq_status);
/* start / push back the echo timer */
mod_timer(&raw->timer, jiffies + msecs_to_jiffies(ECHO_TIMEOUT_MS));
}
/*
* Echo timer callback function.
* The raw decoders expect to get a final sample even if there are no edges, in
* order to be assured of the final space. If there are no edges for a certain
* time we use this timer to emit a final sample to satisfy them.
*/
static void img_ir_echo_timer(unsigned long arg)
{
struct img_ir_priv *priv = (struct img_ir_priv *)arg;
spin_lock_irq(&priv->lock);
/* check not removing */
if (priv->raw.rdev)
/*
* It's safe to pass irq_status=0 since it's only used to check
* for double edges.
*/
img_ir_refresh_raw(priv, 0);
spin_unlock_irq(&priv->lock);
}
void img_ir_setup_raw(struct img_ir_priv *priv)
{
u32 irq_en;
if (!priv->raw.rdev)
return;
/* clear and enable edge interrupts */
spin_lock_irq(&priv->lock);
irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
irq_en |= IMG_IR_IRQ_EDGE;
img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);
spin_unlock_irq(&priv->lock);
}
int img_ir_probe_raw(struct img_ir_priv *priv)
{
struct img_ir_priv_raw *raw = &priv->raw;
struct rc_dev *rdev;
int error;
/* Set up the echo timer */
setup_timer(&raw->timer, img_ir_echo_timer, (unsigned long)priv);
/* Allocate raw decoder */
raw->rdev = rdev = rc_allocate_device();
if (!rdev) {
dev_err(priv->dev, "cannot allocate raw input device\n");
return -ENOMEM;
}
rdev->priv = priv;
rdev->map_name = RC_MAP_EMPTY;
rdev->input_name = "IMG Infrared Decoder Raw";
rdev->driver_type = RC_DRIVER_IR_RAW;
/* Register raw decoder */
error = rc_register_device(rdev);
if (error) {
dev_err(priv->dev, "failed to register raw IR input device\n");
rc_free_device(rdev);
raw->rdev = NULL;
return error;
}
return 0;
}
void img_ir_remove_raw(struct img_ir_priv *priv)
{
struct img_ir_priv_raw *raw = &priv->raw;
struct rc_dev *rdev = raw->rdev;
u32 irq_en;
if (!rdev)
return;
/* switch off and disable raw (edge) interrupts */
spin_lock_irq(&priv->lock);
raw->rdev = NULL;
irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
irq_en &= ~IMG_IR_IRQ_EDGE;
img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);
img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
spin_unlock_irq(&priv->lock);
rc_unregister_device(rdev);
del_timer_sync(&raw->timer);
}