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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * ImgTec IR Raw Decoder found in PowerDown Controller.4 *5 * Copyright 2010-2014 Imagination Technologies Ltd.6 *7 * This ties into the input subsystem using the RC-core in raw mode. Raw IR8 * signal edges are reported and decoded by generic software decoders.9 */10 11#include <linux/spinlock.h>12#include <media/rc-core.h>13#include "img-ir.h"14 15#define ECHO_TIMEOUT_MS 150 /* ms between echos */16 17/* must be called with priv->lock held */18static void img_ir_refresh_raw(struct img_ir_priv *priv, u32 irq_status)19{20 struct img_ir_priv_raw *raw = &priv->raw;21 struct rc_dev *rc_dev = priv->raw.rdev;22 int multiple;23 u32 ir_status;24 25 /* find whether both rise and fall was detected */26 multiple = ((irq_status & IMG_IR_IRQ_EDGE) == IMG_IR_IRQ_EDGE);27 /*28 * If so, we need to see if the level has actually changed.29 * If it's just noise that we didn't have time to process,30 * there's no point reporting it.31 */32 ir_status = img_ir_read(priv, IMG_IR_STATUS) & IMG_IR_IRRXD;33 if (multiple && ir_status == raw->last_status)34 return;35 raw->last_status = ir_status;36 37 /* report the edge to the IR raw decoders */38 if (ir_status) /* low */39 ir_raw_event_store_edge(rc_dev, false);40 else /* high */41 ir_raw_event_store_edge(rc_dev, true);42 ir_raw_event_handle(rc_dev);43}44 45/* called with priv->lock held */46void img_ir_isr_raw(struct img_ir_priv *priv, u32 irq_status)47{48 struct img_ir_priv_raw *raw = &priv->raw;49 50 /* check not removing */51 if (!raw->rdev)52 return;53 54 img_ir_refresh_raw(priv, irq_status);55 56 /* start / push back the echo timer */57 mod_timer(&raw->timer, jiffies + msecs_to_jiffies(ECHO_TIMEOUT_MS));58}59 60/*61 * Echo timer callback function.62 * The raw decoders expect to get a final sample even if there are no edges, in63 * order to be assured of the final space. If there are no edges for a certain64 * time we use this timer to emit a final sample to satisfy them.65 */66static void img_ir_echo_timer(struct timer_list *t)67{68 struct img_ir_priv *priv = from_timer(priv, t, raw.timer);69 70 spin_lock_irq(&priv->lock);71 72 /* check not removing */73 if (priv->raw.rdev)74 /*75 * It's safe to pass irq_status=0 since it's only used to check76 * for double edges.77 */78 img_ir_refresh_raw(priv, 0);79 80 spin_unlock_irq(&priv->lock);81}82 83void img_ir_setup_raw(struct img_ir_priv *priv)84{85 u32 irq_en;86 87 if (!priv->raw.rdev)88 return;89 90 /* clear and enable edge interrupts */91 spin_lock_irq(&priv->lock);92 irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);93 irq_en |= IMG_IR_IRQ_EDGE;94 img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);95 img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);96 spin_unlock_irq(&priv->lock);97}98 99int img_ir_probe_raw(struct img_ir_priv *priv)100{101 struct img_ir_priv_raw *raw = &priv->raw;102 struct rc_dev *rdev;103 int error;104 105 /* Set up the echo timer */106 timer_setup(&raw->timer, img_ir_echo_timer, 0);107 108 /* Allocate raw decoder */109 raw->rdev = rdev = rc_allocate_device(RC_DRIVER_IR_RAW);110 if (!rdev) {111 dev_err(priv->dev, "cannot allocate raw input device\n");112 return -ENOMEM;113 }114 rdev->priv = priv;115 rdev->map_name = RC_MAP_EMPTY;116 rdev->device_name = "IMG Infrared Decoder Raw";117 118 /* Register raw decoder */119 error = rc_register_device(rdev);120 if (error) {121 dev_err(priv->dev, "failed to register raw IR input device\n");122 rc_free_device(rdev);123 raw->rdev = NULL;124 return error;125 }126 127 return 0;128}129 130void img_ir_remove_raw(struct img_ir_priv *priv)131{132 struct img_ir_priv_raw *raw = &priv->raw;133 struct rc_dev *rdev = raw->rdev;134 u32 irq_en;135 136 if (!rdev)137 return;138 139 /* switch off and disable raw (edge) interrupts */140 spin_lock_irq(&priv->lock);141 raw->rdev = NULL;142 irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);143 irq_en &= ~IMG_IR_IRQ_EDGE;144 img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);145 img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);146 spin_unlock_irq(&priv->lock);147 148 rc_unregister_device(rdev);149 150 del_timer_sync(&raw->timer);151}152