// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* ImgTec IR Raw Decoder found in PowerDown Controller.
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*
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* Copyright 2010-2014 Imagination Technologies Ltd.
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*
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* This ties into the input subsystem using the RC-core in raw mode. Raw IR
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* signal edges are reported and decoded by generic software decoders.
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*/
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#include <linux/spinlock.h>
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#include <media/rc-core.h>
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#include "img-ir.h"
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#define ECHO_TIMEOUT_MS 150 /* ms between echos */
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/* must be called with priv->lock held */
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static void img_ir_refresh_raw(struct img_ir_priv *priv, u32 irq_status)
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{
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struct img_ir_priv_raw *raw = &priv->raw;
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struct rc_dev *rc_dev = priv->raw.rdev;
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int multiple;
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u32 ir_status;
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/* find whether both rise and fall was detected */
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multiple = ((irq_status & IMG_IR_IRQ_EDGE) == IMG_IR_IRQ_EDGE);
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/*
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* If so, we need to see if the level has actually changed.
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* If it's just noise that we didn't have time to process,
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* there's no point reporting it.
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*/
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ir_status = img_ir_read(priv, IMG_IR_STATUS) & IMG_IR_IRRXD;
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if (multiple && ir_status == raw->last_status)
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return;
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raw->last_status = ir_status;
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/* report the edge to the IR raw decoders */
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if (ir_status) /* low */
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ir_raw_event_store_edge(rc_dev, false);
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else /* high */
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ir_raw_event_store_edge(rc_dev, true);
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ir_raw_event_handle(rc_dev);
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}
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/* called with priv->lock held */
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void img_ir_isr_raw(struct img_ir_priv *priv, u32 irq_status)
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{
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struct img_ir_priv_raw *raw = &priv->raw;
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/* check not removing */
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if (!raw->rdev)
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return;
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img_ir_refresh_raw(priv, irq_status);
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/* start / push back the echo timer */
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mod_timer(&raw->timer, jiffies + msecs_to_jiffies(ECHO_TIMEOUT_MS));
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}
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/*
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* Echo timer callback function.
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* The raw decoders expect to get a final sample even if there are no edges, in
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* order to be assured of the final space. If there are no edges for a certain
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* time we use this timer to emit a final sample to satisfy them.
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*/
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static void img_ir_echo_timer(struct timer_list *t)
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{
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struct img_ir_priv *priv = from_timer(priv, t, raw.timer);
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spin_lock_irq(&priv->lock);
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/* check not removing */
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if (priv->raw.rdev)
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/*
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* It's safe to pass irq_status=0 since it's only used to check
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* for double edges.
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*/
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img_ir_refresh_raw(priv, 0);
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spin_unlock_irq(&priv->lock);
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}
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void img_ir_setup_raw(struct img_ir_priv *priv)
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{
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u32 irq_en;
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if (!priv->raw.rdev)
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return;
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/* clear and enable edge interrupts */
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spin_lock_irq(&priv->lock);
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irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
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irq_en |= IMG_IR_IRQ_EDGE;
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img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
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img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);
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spin_unlock_irq(&priv->lock);
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}
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int img_ir_probe_raw(struct img_ir_priv *priv)
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{
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struct img_ir_priv_raw *raw = &priv->raw;
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struct rc_dev *rdev;
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int error;
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/* Set up the echo timer */
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timer_setup(&raw->timer, img_ir_echo_timer, 0);
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/* Allocate raw decoder */
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raw->rdev = rdev = rc_allocate_device(RC_DRIVER_IR_RAW);
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if (!rdev) {
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dev_err(priv->dev, "cannot allocate raw input device\n");
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return -ENOMEM;
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}
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rdev->priv = priv;
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rdev->map_name = RC_MAP_EMPTY;
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rdev->device_name = "IMG Infrared Decoder Raw";
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/* Register raw decoder */
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error = rc_register_device(rdev);
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if (error) {
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dev_err(priv->dev, "failed to register raw IR input device\n");
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rc_free_device(rdev);
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raw->rdev = NULL;
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return error;
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}
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return 0;
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}
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void img_ir_remove_raw(struct img_ir_priv *priv)
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{
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struct img_ir_priv_raw *raw = &priv->raw;
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struct rc_dev *rdev = raw->rdev;
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u32 irq_en;
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if (!rdev)
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return;
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/* switch off and disable raw (edge) interrupts */
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spin_lock_irq(&priv->lock);
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raw->rdev = NULL;
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irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
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irq_en &= ~IMG_IR_IRQ_EDGE;
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img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);
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img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
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spin_unlock_irq(&priv->lock);
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rc_unregister_device(rdev);
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del_timer_sync(&raw->timer);
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}
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