// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ImgTec IR Hardware Decoder found in PowerDown Controller.
 *
 * Copyright 2010-2014 Imagination Technologies Ltd.
 *
 * This ties into the input subsystem using the RC-core. Protocol support is
 * provided in separate modules which provide the parameters and scancode
 * translation functions to set up the hardware decoder and interpret the
 * resulting input.
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <media/rc-core.h>
#include "img-ir.h"

/* Decoders lock (only modified to preprocess them) */
static DEFINE_SPINLOCK(img_ir_decoders_lock);

static bool img_ir_decoders_preprocessed;
static struct img_ir_decoder *img_ir_decoders[] = {
#ifdef CONFIG_IR_IMG_NEC
        &img_ir_nec,
#endif
#ifdef CONFIG_IR_IMG_JVC
        &img_ir_jvc,
#endif
#ifdef CONFIG_IR_IMG_SONY
        &img_ir_sony,
#endif
#ifdef CONFIG_IR_IMG_SHARP
        &img_ir_sharp,
#endif
#ifdef CONFIG_IR_IMG_SANYO
        &img_ir_sanyo,
#endif
#ifdef CONFIG_IR_IMG_RC5
        &img_ir_rc5,
#endif
#ifdef CONFIG_IR_IMG_RC6
        &img_ir_rc6,
#endif
        NULL
};

#define IMG_IR_F_FILTER         BIT(RC_FILTER_NORMAL)   /* enable filtering */
#define IMG_IR_F_WAKE           BIT(RC_FILTER_WAKEUP)   /* enable waking */

/* code type quirks */

#define IMG_IR_QUIRK_CODE_BROKEN        0x1     /* Decode is broken */
#define IMG_IR_QUIRK_CODE_LEN_INCR      0x2     /* Bit length needs increment */
/*
 * The decoder generates rapid interrupts without actually having
 * received any new data after an incomplete IR code is decoded.
 */
#define IMG_IR_QUIRK_CODE_IRQ           0x4

/* functions for preprocessing timings, ensuring max is set */

static void img_ir_timing_preprocess(struct img_ir_timing_range *range,
                                     unsigned int unit)
{
        if (range->max < range->min)
                range->max = range->min;
        if (unit) {
                /* multiply by unit and convert to microseconds */
                range->min = (range->min*unit)/1000;
                range->max = (range->max*unit + 999)/1000; /* round up */
        }
}

static void img_ir_symbol_timing_preprocess(struct img_ir_symbol_timing *timing,
                                            unsigned int unit)
{
        img_ir_timing_preprocess(&timing->pulse, unit);
        img_ir_timing_preprocess(&timing->space, unit);
}

static void img_ir_timings_preprocess(struct img_ir_timings *timings,
                                      unsigned int unit)
{
        img_ir_symbol_timing_preprocess(&timings->ldr, unit);
        img_ir_symbol_timing_preprocess(&timings->s00, unit);
        img_ir_symbol_timing_preprocess(&timings->s01, unit);
        img_ir_symbol_timing_preprocess(&timings->s10, unit);
        img_ir_symbol_timing_preprocess(&timings->s11, unit);
        /* default s10 and s11 to s00 and s01 if no leader */
        if (unit)
                /* multiply by unit and convert to microseconds (round up) */
                timings->ft.ft_min = (timings->ft.ft_min*unit + 999)/1000;
}

/* functions for filling empty fields with defaults */

static void img_ir_timing_defaults(struct img_ir_timing_range *range,
                                   struct img_ir_timing_range *defaults)
{
        if (!range->min)
                range->min = defaults->min;
        if (!range->max)
                range->max = defaults->max;
}

static void img_ir_symbol_timing_defaults(struct img_ir_symbol_timing *timing,
                                          struct img_ir_symbol_timing *defaults)
{
        img_ir_timing_defaults(&timing->pulse, &defaults->pulse);
        img_ir_timing_defaults(&timing->space, &defaults->space);
}

static void img_ir_timings_defaults(struct img_ir_timings *timings,
                                    struct img_ir_timings *defaults)
{
        img_ir_symbol_timing_defaults(&timings->ldr, &defaults->ldr);
        img_ir_symbol_timing_defaults(&timings->s00, &defaults->s00);
        img_ir_symbol_timing_defaults(&timings->s01, &defaults->s01);
        img_ir_symbol_timing_defaults(&timings->s10, &defaults->s10);
        img_ir_symbol_timing_defaults(&timings->s11, &defaults->s11);
        if (!timings->ft.ft_min)
                timings->ft.ft_min = defaults->ft.ft_min;
}

/* functions for converting timings to register values */

/**
 * img_ir_control() - Convert control struct to control register value.
 * @control:    Control data
 *
 * Returns:     The control register value equivalent of @control.
 */
static u32 img_ir_control(const struct img_ir_control *control)
{
        u32 ctrl = control->code_type << IMG_IR_CODETYPE_SHIFT;
        if (control->decoden)
                ctrl |= IMG_IR_DECODEN;
        if (control->hdrtog)
                ctrl |= IMG_IR_HDRTOG;
        if (control->ldrdec)
                ctrl |= IMG_IR_LDRDEC;
        if (control->decodinpol)
                ctrl |= IMG_IR_DECODINPOL;
        if (control->bitorien)
                ctrl |= IMG_IR_BITORIEN;
        if (control->d1validsel)
                ctrl |= IMG_IR_D1VALIDSEL;
        if (control->bitinv)
                ctrl |= IMG_IR_BITINV;
        if (control->decodend2)
                ctrl |= IMG_IR_DECODEND2;
        if (control->bitoriend2)
                ctrl |= IMG_IR_BITORIEND2;
        if (control->bitinvd2)
                ctrl |= IMG_IR_BITINVD2;
        return ctrl;
}

/**
 * img_ir_timing_range_convert() - Convert microsecond range.
 * @out:        Output timing range in clock cycles with a shift.
 * @in:         Input timing range in microseconds.
 * @tolerance:  Tolerance as a fraction of 128 (roughly percent).
 * @clock_hz:   IR clock rate in Hz.
 * @shift:      Shift of output units.
 *
 * Converts min and max from microseconds to IR clock cycles, applies a
 * tolerance, and shifts for the register, rounding in the right direction.
 * Note that in and out can safely be the same object.
 */
static void img_ir_timing_range_convert(struct img_ir_timing_range *out,
                                        const struct img_ir_timing_range *in,
                                        unsigned int tolerance,
                                        unsigned long clock_hz,
                                        unsigned int shift)
{
        unsigned int min = in->min;
        unsigned int max = in->max;
        /* add a tolerance */
        min = min - (min*tolerance >> 7);
        max = max + (max*tolerance >> 7);
        /* convert from microseconds into clock cycles */
        min = min*clock_hz / 1000000;
        max = (max*clock_hz + 999999) / 1000000; /* round up */
        /* apply shift and copy to output */
        out->min = min >> shift;
        out->max = (max + ((1 << shift) - 1)) >> shift; /* round up */
}

/**
 * img_ir_symbol_timing() - Convert symbol timing struct to register value.
 * @timing:     Symbol timing data
 * @tolerance:  Timing tolerance where 0-128 represents 0-100%
 * @clock_hz:   Frequency of source clock in Hz
 * @pd_shift:   Shift to apply to symbol period
 * @w_shift:    Shift to apply to symbol width
 *
 * Returns:     Symbol timing register value based on arguments.
 */
static u32 img_ir_symbol_timing(const struct img_ir_symbol_timing *timing,
                                unsigned int tolerance,
                                unsigned long clock_hz,
                                unsigned int pd_shift,
                                unsigned int w_shift)
{
        struct img_ir_timing_range hw_pulse, hw_period;
        /* we calculate period in hw_period, then convert in place */
        hw_period.min = timing->pulse.min + timing->space.min;
        hw_period.max = timing->pulse.max + timing->space.max;
        img_ir_timing_range_convert(&hw_period, &hw_period,
                        tolerance, clock_hz, pd_shift);
        img_ir_timing_range_convert(&hw_pulse, &timing->pulse,
                        tolerance, clock_hz, w_shift);
        /* construct register value */
        return  (hw_period.max  << IMG_IR_PD_MAX_SHIFT) |
                (hw_period.min  << IMG_IR_PD_MIN_SHIFT) |
                (hw_pulse.max   << IMG_IR_W_MAX_SHIFT)  |
                (hw_pulse.min   << IMG_IR_W_MIN_SHIFT);
}

/**
 * img_ir_free_timing() - Convert free time timing struct to register value.
 * @timing:     Free symbol timing data
 * @clock_hz:   Source clock frequency in Hz
 *
 * Returns:     Free symbol timing register value.
 */
static u32 img_ir_free_timing(const struct img_ir_free_timing *timing,
                              unsigned long clock_hz)
{
        unsigned int minlen, maxlen, ft_min;
        /* minlen is only 5 bits, and round minlen to multiple of 2 */
        if (timing->minlen < 30)
                minlen = timing->minlen & -2;
        else
                minlen = 30;
        /* maxlen has maximum value of 48, and round maxlen to multiple of 2 */
        if (timing->maxlen < 48)
                maxlen = (timing->maxlen + 1) & -2;
        else
                maxlen = 48;
        /* convert and shift ft_min, rounding upwards */
        ft_min = (timing->ft_min*clock_hz + 999999) / 1000000;
        ft_min = (ft_min + 7) >> 3;
        /* construct register value */
        return  (maxlen << IMG_IR_MAXLEN_SHIFT) |
                (minlen << IMG_IR_MINLEN_SHIFT) |
                (ft_min << IMG_IR_FT_MIN_SHIFT);
}

/**
 * img_ir_free_timing_dynamic() - Update free time register value.
 * @st_ft:      Static free time register value from img_ir_free_timing.
 * @filter:     Current filter which may additionally restrict min/max len.
 *
 * Returns:     Updated free time register value based on the current filter.
 */
static u32 img_ir_free_timing_dynamic(u32 st_ft, struct img_ir_filter *filter)
{
        unsigned int minlen, maxlen, newminlen, newmaxlen;

        /* round minlen, maxlen to multiple of 2 */
        newminlen = filter->minlen & -2;
        newmaxlen = (filter->maxlen + 1) & -2;
        /* extract min/max len from register */
        minlen = (st_ft & IMG_IR_MINLEN) >> IMG_IR_MINLEN_SHIFT;
        maxlen = (st_ft & IMG_IR_MAXLEN) >> IMG_IR_MAXLEN_SHIFT;
        /* if the new values are more restrictive, update the register value */
        if (newminlen > minlen) {
                st_ft &= ~IMG_IR_MINLEN;
                st_ft |= newminlen << IMG_IR_MINLEN_SHIFT;
        }
        if (newmaxlen < maxlen) {
                st_ft &= ~IMG_IR_MAXLEN;
                st_ft |= newmaxlen << IMG_IR_MAXLEN_SHIFT;
        }
        return st_ft;
}

/**
 * img_ir_timings_convert() - Convert timings to register values
 * @regs:       Output timing register values
 * @timings:    Input timing data
 * @tolerance:  Timing tolerance where 0-128 represents 0-100%
 * @clock_hz:   Source clock frequency in Hz
 */
static void img_ir_timings_convert(struct img_ir_timing_regvals *regs,
                                   const struct img_ir_timings *timings,
                                   unsigned int tolerance,
                                   unsigned int clock_hz)
{
        /* leader symbol timings are divided by 16 */
        regs->ldr = img_ir_symbol_timing(&timings->ldr, tolerance, clock_hz,
                        4, 4);
        /* other symbol timings, pd fields only are divided by 2 */
        regs->s00 = img_ir_symbol_timing(&timings->s00, tolerance, clock_hz,
                        1, 0);
        regs->s01 = img_ir_symbol_timing(&timings->s01, tolerance, clock_hz,
                        1, 0);
        regs->s10 = img_ir_symbol_timing(&timings->s10, tolerance, clock_hz,
                        1, 0);
        regs->s11 = img_ir_symbol_timing(&timings->s11, tolerance, clock_hz,
                        1, 0);
        regs->ft = img_ir_free_timing(&timings->ft, clock_hz);
}

/**
 * img_ir_decoder_preprocess() - Preprocess timings in decoder.
 * @decoder:    Decoder to be preprocessed.
 *
 * Ensures that the symbol timing ranges are valid with respect to ordering, and
 * does some fixed conversion on them.
 */
static void img_ir_decoder_preprocess(struct img_ir_decoder *decoder)
{
        /* default tolerance */
        if (!decoder->tolerance)
                decoder->tolerance = 10; /* percent */
        /* and convert tolerance to fraction out of 128 */
        decoder->tolerance = decoder->tolerance * 128 / 100;

        /* fill in implicit fields */
        img_ir_timings_preprocess(&decoder->timings, decoder->unit);

        /* do the same for repeat timings if applicable */
        if (decoder->repeat) {
                img_ir_timings_preprocess(&decoder->rtimings, decoder->unit);
                img_ir_timings_defaults(&decoder->rtimings, &decoder->timings);
        }
}

/**
 * img_ir_decoder_convert() - Generate internal timings in decoder.
 * @decoder:    Decoder to be converted to internal timings.
 * @reg_timings: Timing register values.
 * @clock_hz:   IR clock rate in Hz.
 *
 * Fills out the repeat timings and timing register values for a specific clock
 * rate.
 */
static void img_ir_decoder_convert(const struct img_ir_decoder *decoder,
                                   struct img_ir_reg_timings *reg_timings,
                                   unsigned int clock_hz)
{
        /* calculate control value */
        reg_timings->ctrl = img_ir_control(&decoder->control);

        /* fill in implicit fields and calculate register values */
        img_ir_timings_convert(&reg_timings->timings, &decoder->timings,
                               decoder->tolerance, clock_hz);

        /* do the same for repeat timings if applicable */
        if (decoder->repeat)
                img_ir_timings_convert(&reg_timings->rtimings,
                                       &decoder->rtimings, decoder->tolerance,
                                       clock_hz);
}

/**
 * img_ir_write_timings() - Write timings to the hardware now
 * @priv:       IR private data
 * @regs:       Timing register values to write
 * @type:       RC filter type (RC_FILTER_*)
 *
 * Write timing register values @regs to the hardware, taking into account the
 * current filter which may impose restrictions on the length of the expected
 * data.
 */
static void img_ir_write_timings(struct img_ir_priv *priv,
                                 struct img_ir_timing_regvals *regs,
                                 enum rc_filter_type type)
{
        struct img_ir_priv_hw *hw = &priv->hw;

        /* filter may be more restrictive to minlen, maxlen */
        u32 ft = regs->ft;
        if (hw->flags & BIT(type))
                ft = img_ir_free_timing_dynamic(regs->ft, &hw->filters[type]);
        /* write to registers */
        img_ir_write(priv, IMG_IR_LEAD_SYMB_TIMING, regs->ldr);
        img_ir_write(priv, IMG_IR_S00_SYMB_TIMING, regs->s00);
        img_ir_write(priv, IMG_IR_S01_SYMB_TIMING, regs->s01);
        img_ir_write(priv, IMG_IR_S10_SYMB_TIMING, regs->s10);
        img_ir_write(priv, IMG_IR_S11_SYMB_TIMING, regs->s11);
        img_ir_write(priv, IMG_IR_FREE_SYMB_TIMING, ft);
        dev_dbg(priv->dev, "timings: ldr=%#x, s=[%#x, %#x, %#x, %#x], ft=%#x\n",
                regs->ldr, regs->s00, regs->s01, regs->s10, regs->s11, ft);
}

static void img_ir_write_filter(struct img_ir_priv *priv,
                                struct img_ir_filter *filter)
{
        if (filter) {
                dev_dbg(priv->dev, "IR filter=%016llx & %016llx\n",
                        (unsigned long long)filter->data,
                        (unsigned long long)filter->mask);
                img_ir_write(priv, IMG_IR_IRQ_MSG_DATA_LW, (u32)filter->data);
                img_ir_write(priv, IMG_IR_IRQ_MSG_DATA_UP, (u32)(filter->data
                                                                        >> 32));
                img_ir_write(priv, IMG_IR_IRQ_MSG_MASK_LW, (u32)filter->mask);
                img_ir_write(priv, IMG_IR_IRQ_MSG_MASK_UP, (u32)(filter->mask
                                                                        >> 32));
        } else {
                dev_dbg(priv->dev, "IR clearing filter\n");
                img_ir_write(priv, IMG_IR_IRQ_MSG_MASK_LW, 0);
                img_ir_write(priv, IMG_IR_IRQ_MSG_MASK_UP, 0);
        }
}

/* caller must have lock */
static void _img_ir_set_filter(struct img_ir_priv *priv,
                               struct img_ir_filter *filter)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        u32 irq_en, irq_on;

        irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
        if (filter) {
                /* Only use the match interrupt */
                hw->filters[RC_FILTER_NORMAL] = *filter;
                hw->flags |= IMG_IR_F_FILTER;
                irq_on = IMG_IR_IRQ_DATA_MATCH;
                irq_en &= ~(IMG_IR_IRQ_DATA_VALID | IMG_IR_IRQ_DATA2_VALID);
        } else {
                /* Only use the valid interrupt */
                hw->flags &= ~IMG_IR_F_FILTER;
                irq_en &= ~IMG_IR_IRQ_DATA_MATCH;
                irq_on = IMG_IR_IRQ_DATA_VALID | IMG_IR_IRQ_DATA2_VALID;
        }
        irq_en |= irq_on;

        img_ir_write_filter(priv, filter);
        /* clear any interrupts we're enabling so we don't handle old ones */
        img_ir_write(priv, IMG_IR_IRQ_CLEAR, irq_on);
        img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en);
}

/* caller must have lock */
static void _img_ir_set_wake_filter(struct img_ir_priv *priv,
                                    struct img_ir_filter *filter)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        if (filter) {
                /* Enable wake, and copy filter for later */
                hw->filters[RC_FILTER_WAKEUP] = *filter;
                hw->flags |= IMG_IR_F_WAKE;
        } else {
                /* Disable wake */
                hw->flags &= ~IMG_IR_F_WAKE;
        }
}

/* Callback for setting scancode filter */
static int img_ir_set_filter(struct rc_dev *dev, enum rc_filter_type type,
                             struct rc_scancode_filter *sc_filter)
{
        struct img_ir_priv *priv = dev->priv;
        struct img_ir_priv_hw *hw = &priv->hw;
        struct img_ir_filter filter, *filter_ptr = &filter;
        int ret = 0;

        dev_dbg(priv->dev, "IR scancode %sfilter=%08x & %08x\n",
                type == RC_FILTER_WAKEUP ? "wake " : "",
                sc_filter->data,
                sc_filter->mask);

        spin_lock_irq(&priv->lock);

        /* filtering can always be disabled */
        if (!sc_filter->mask) {
                filter_ptr = NULL;
                goto set_unlock;
        }

        /* current decoder must support scancode filtering */
        if (!hw->decoder || !hw->decoder->filter) {
                ret = -EINVAL;
                goto unlock;
        }

        /* convert scancode filter to raw filter */
        filter.minlen = 0;
        filter.maxlen = ~0;
        if (type == RC_FILTER_NORMAL) {
                /* guess scancode from protocol */
                ret = hw->decoder->filter(sc_filter, &filter,
                                          dev->enabled_protocols);
        } else {
                /* for wakeup user provided exact protocol variant */
                ret = hw->decoder->filter(sc_filter, &filter,
                                          1ULL << dev->wakeup_protocol);
        }
        if (ret)
                goto unlock;
        dev_dbg(priv->dev, "IR raw %sfilter=%016llx & %016llx\n",
                type == RC_FILTER_WAKEUP ? "wake " : "",
                (unsigned long long)filter.data,
                (unsigned long long)filter.mask);

set_unlock:
        /* apply raw filters */
        switch (type) {
        case RC_FILTER_NORMAL:
                _img_ir_set_filter(priv, filter_ptr);
                break;
        case RC_FILTER_WAKEUP:
                _img_ir_set_wake_filter(priv, filter_ptr);
                break;
        default:
                ret = -EINVAL;
        }

unlock:
        spin_unlock_irq(&priv->lock);
        return ret;
}

static int img_ir_set_normal_filter(struct rc_dev *dev,
                                    struct rc_scancode_filter *sc_filter)
{
        return img_ir_set_filter(dev, RC_FILTER_NORMAL, sc_filter);
}

static int img_ir_set_wakeup_filter(struct rc_dev *dev,
                                    struct rc_scancode_filter *sc_filter)
{
        return img_ir_set_filter(dev, RC_FILTER_WAKEUP, sc_filter);
}

/**
 * img_ir_set_decoder() - Set the current decoder.
 * @priv:       IR private data.
 * @decoder:    Decoder to use with immediate effect.
 * @proto:      Protocol bitmap (or 0 to use decoder->type).
 */
static void img_ir_set_decoder(struct img_ir_priv *priv,
                               const struct img_ir_decoder *decoder,
                               u64 proto)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        struct rc_dev *rdev = hw->rdev;
        u32 ir_status, irq_en;
        spin_lock_irq(&priv->lock);

        /*
         * First record that the protocol is being stopped so that the end timer
         * isn't restarted while we're trying to stop it.
         */
        hw->stopping = true;

        /*
         * Release the lock to stop the end timer, since the end timer handler
         * acquires the lock and we don't want to deadlock waiting for it.
         */
        spin_unlock_irq(&priv->lock);
        del_timer_sync(&hw->end_timer);
        del_timer_sync(&hw->suspend_timer);
        spin_lock_irq(&priv->lock);

        hw->stopping = false;

        /* switch off and disable interrupts */
        img_ir_write(priv, IMG_IR_CONTROL, 0);
        irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
        img_ir_write(priv, IMG_IR_IRQ_ENABLE, irq_en & IMG_IR_IRQ_EDGE);
        img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_ALL & ~IMG_IR_IRQ_EDGE);

        /* ack any data already detected */
        ir_status = img_ir_read(priv, IMG_IR_STATUS);
        if (ir_status & (IMG_IR_RXDVAL | IMG_IR_RXDVALD2)) {
                ir_status &= ~(IMG_IR_RXDVAL | IMG_IR_RXDVALD2);
                img_ir_write(priv, IMG_IR_STATUS, ir_status);
        }

        /* always read data to clear buffer if IR wakes the device */
        img_ir_read(priv, IMG_IR_DATA_LW);
        img_ir_read(priv, IMG_IR_DATA_UP);

        /* switch back to normal mode */
        hw->mode = IMG_IR_M_NORMAL;

        /* clear the wakeup scancode filter */
        rdev->scancode_wakeup_filter.data = 0;
        rdev->scancode_wakeup_filter.mask = 0;
        rdev->wakeup_protocol = RC_PROTO_UNKNOWN;

        /* clear raw filters */
        _img_ir_set_filter(priv, NULL);
        _img_ir_set_wake_filter(priv, NULL);

        /* clear the enabled protocols */
        hw->enabled_protocols = 0;

        /* switch decoder */
        hw->decoder = decoder;
        if (!decoder)
                goto unlock;

        /* set the enabled protocols */
        if (!proto)
                proto = decoder->type;
        hw->enabled_protocols = proto;

        /* write the new timings */
        img_ir_decoder_convert(decoder, &hw->reg_timings, hw->clk_hz);
        img_ir_write_timings(priv, &hw->reg_timings.timings, RC_FILTER_NORMAL);

        /* set up and enable */
        img_ir_write(priv, IMG_IR_CONTROL, hw->reg_timings.ctrl);


unlock:
        spin_unlock_irq(&priv->lock);
}

/**
 * img_ir_decoder_compatible() - Find whether a decoder will work with a device.
 * @priv:       IR private data.
 * @dec:        Decoder to check.
 *
 * Returns:     true if @dec is compatible with the device @priv refers to.
 */
static bool img_ir_decoder_compatible(struct img_ir_priv *priv,
                                      const struct img_ir_decoder *dec)
{
        unsigned int ct;

        /* don't accept decoders using code types which aren't supported */
        ct = dec->control.code_type;
        if (priv->hw.ct_quirks[ct] & IMG_IR_QUIRK_CODE_BROKEN)
                return false;

        return true;
}

/**
 * img_ir_allowed_protos() - Get allowed protocols from global decoder list.
 * @priv:       IR private data.
 *
 * Returns:     Mask of protocols supported by the device @priv refers to.
 */
static u64 img_ir_allowed_protos(struct img_ir_priv *priv)
{
        u64 protos = 0;
        struct img_ir_decoder **decp;

        for (decp = img_ir_decoders; *decp; ++decp) {
                const struct img_ir_decoder *dec = *decp;
                if (img_ir_decoder_compatible(priv, dec))
                        protos |= dec->type;
        }
        return protos;
}

/* Callback for changing protocol using sysfs */
static int img_ir_change_protocol(struct rc_dev *dev, u64 *ir_type)
{
        struct img_ir_priv *priv = dev->priv;
        struct img_ir_priv_hw *hw = &priv->hw;
        struct rc_dev *rdev = hw->rdev;
        struct img_ir_decoder **decp;
        u64 wakeup_protocols;

        if (!*ir_type) {
                /* disable all protocols */
                img_ir_set_decoder(priv, NULL, 0);
                goto success;
        }
        for (decp = img_ir_decoders; *decp; ++decp) {
                const struct img_ir_decoder *dec = *decp;
                if (!img_ir_decoder_compatible(priv, dec))
                        continue;
                if (*ir_type & dec->type) {
                        *ir_type &= dec->type;
                        img_ir_set_decoder(priv, dec, *ir_type);
                        goto success;
                }
        }
        return -EINVAL;

success:
        /*
         * Only allow matching wakeup protocols for now, and only if filtering
         * is supported.
         */
        wakeup_protocols = *ir_type;
        if (!hw->decoder || !hw->decoder->filter)
                wakeup_protocols = 0;
        rdev->allowed_wakeup_protocols = wakeup_protocols;
        return 0;
}

/* Changes ir-core protocol device attribute */
static void img_ir_set_protocol(struct img_ir_priv *priv, u64 proto)
{
        struct rc_dev *rdev = priv->hw.rdev;

        mutex_lock(&rdev->lock);
        rdev->enabled_protocols = proto;
        rdev->allowed_wakeup_protocols = proto;
        mutex_unlock(&rdev->lock);
}

/* Set up IR decoders */
static void img_ir_init_decoders(void)
{
        struct img_ir_decoder **decp;

        spin_lock(&img_ir_decoders_lock);
        if (!img_ir_decoders_preprocessed) {
                for (decp = img_ir_decoders; *decp; ++decp)
                        img_ir_decoder_preprocess(*decp);
                img_ir_decoders_preprocessed = true;
        }
        spin_unlock(&img_ir_decoders_lock);
}

#ifdef CONFIG_PM_SLEEP
/**
 * img_ir_enable_wake() - Switch to wake mode.
 * @priv:       IR private data.
 *
 * Returns:     non-zero if the IR can wake the system.
 */
static int img_ir_enable_wake(struct img_ir_priv *priv)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        int ret = 0;

        spin_lock_irq(&priv->lock);
        if (hw->flags & IMG_IR_F_WAKE) {
                /* interrupt only on a match */
                hw->suspend_irqen = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
                img_ir_write(priv, IMG_IR_IRQ_ENABLE, IMG_IR_IRQ_DATA_MATCH);
                img_ir_write_filter(priv, &hw->filters[RC_FILTER_WAKEUP]);
                img_ir_write_timings(priv, &hw->reg_timings.timings,
                                     RC_FILTER_WAKEUP);
                hw->mode = IMG_IR_M_WAKE;
                ret = 1;
        }
        spin_unlock_irq(&priv->lock);
        return ret;
}

/**
 * img_ir_disable_wake() - Switch out of wake mode.
 * @priv:       IR private data
 *
 * Returns:     1 if the hardware should be allowed to wake from a sleep state.
 *              0 otherwise.
 */
static int img_ir_disable_wake(struct img_ir_priv *priv)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        int ret = 0;

        spin_lock_irq(&priv->lock);
        if (hw->flags & IMG_IR_F_WAKE) {
                /* restore normal filtering */
                if (hw->flags & IMG_IR_F_FILTER) {
                        img_ir_write(priv, IMG_IR_IRQ_ENABLE,
                                     (hw->suspend_irqen & IMG_IR_IRQ_EDGE) |
                                     IMG_IR_IRQ_DATA_MATCH);
                        img_ir_write_filter(priv,
                                            &hw->filters[RC_FILTER_NORMAL]);
                } else {
                        img_ir_write(priv, IMG_IR_IRQ_ENABLE,
                                     (hw->suspend_irqen & IMG_IR_IRQ_EDGE) |
                                     IMG_IR_IRQ_DATA_VALID |
                                     IMG_IR_IRQ_DATA2_VALID);
                        img_ir_write_filter(priv, NULL);
                }
                img_ir_write_timings(priv, &hw->reg_timings.timings,
                                     RC_FILTER_NORMAL);
                hw->mode = IMG_IR_M_NORMAL;
                ret = 1;
        }
        spin_unlock_irq(&priv->lock);
        return ret;
}
#endif /* CONFIG_PM_SLEEP */

/* lock must be held */
static void img_ir_begin_repeat(struct img_ir_priv *priv)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        if (hw->mode == IMG_IR_M_NORMAL) {
                /* switch to repeat timings */
                img_ir_write(priv, IMG_IR_CONTROL, 0);
                hw->mode = IMG_IR_M_REPEATING;
                img_ir_write_timings(priv, &hw->reg_timings.rtimings,
                                     RC_FILTER_NORMAL);
                img_ir_write(priv, IMG_IR_CONTROL, hw->reg_timings.ctrl);
        }
}

/* lock must be held */
static void img_ir_end_repeat(struct img_ir_priv *priv)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        if (hw->mode == IMG_IR_M_REPEATING) {
                /* switch to normal timings */
                img_ir_write(priv, IMG_IR_CONTROL, 0);
                hw->mode = IMG_IR_M_NORMAL;
                img_ir_write_timings(priv, &hw->reg_timings.timings,
                                     RC_FILTER_NORMAL);
                img_ir_write(priv, IMG_IR_CONTROL, hw->reg_timings.ctrl);
        }
}

/* lock must be held */
static void img_ir_handle_data(struct img_ir_priv *priv, u32 len, u64 raw)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        const struct img_ir_decoder *dec = hw->decoder;
        int ret = IMG_IR_SCANCODE;
        struct img_ir_scancode_req request;

        request.protocol = RC_PROTO_UNKNOWN;
        request.toggle   = 0;

        if (dec->scancode)
                ret = dec->scancode(len, raw, hw->enabled_protocols, &request);
        else if (len >= 32)
                request.scancode = (u32)raw;
        else if (len < 32)
                request.scancode = (u32)raw & ((1 << len)-1);
        dev_dbg(priv->dev, "data (%u bits) = %#llx\n",
                len, (unsigned long long)raw);
        if (ret == IMG_IR_SCANCODE) {
                dev_dbg(priv->dev, "decoded scan code %#x, toggle %u\n",
                        request.scancode, request.toggle);
                rc_keydown(hw->rdev, request.protocol, request.scancode,
                           request.toggle);
                img_ir_end_repeat(priv);
        } else if (ret == IMG_IR_REPEATCODE) {
                if (hw->mode == IMG_IR_M_REPEATING) {
                        dev_dbg(priv->dev, "decoded repeat code\n");
                        rc_repeat(hw->rdev);
                } else {
                        dev_dbg(priv->dev, "decoded unexpected repeat code, ignoring\n");
                }
        } else {
                dev_dbg(priv->dev, "decode failed (%d)\n", ret);
                return;
        }


        /* we mustn't update the end timer while trying to stop it */
        if (dec->repeat && !hw->stopping) {
                unsigned long interval;

                img_ir_begin_repeat(priv);

                /* update timer, but allowing for 1/8th tolerance */
                interval = dec->repeat + (dec->repeat >> 3);
                mod_timer(&hw->end_timer,
                          jiffies + msecs_to_jiffies(interval));
        }
}

/* timer function to end waiting for repeat. */
static void img_ir_end_timer(struct timer_list *t)
{
        struct img_ir_priv *priv = from_timer(priv, t, hw.end_timer);

        spin_lock_irq(&priv->lock);
        img_ir_end_repeat(priv);
        spin_unlock_irq(&priv->lock);
}

/*
 * Timer function to re-enable the current protocol after it had been
 * cleared when invalid interrupts were generated due to a quirk in the
 * img-ir decoder.
 */
static void img_ir_suspend_timer(struct timer_list *t)
{
        struct img_ir_priv *priv = from_timer(priv, t, hw.suspend_timer);

        spin_lock_irq(&priv->lock);
        /*
         * Don't overwrite enabled valid/match IRQs if they have already been
         * changed by e.g. a filter change.
         */
        if ((priv->hw.quirk_suspend_irq & IMG_IR_IRQ_EDGE) ==
                                img_ir_read(priv, IMG_IR_IRQ_ENABLE))
                img_ir_write(priv, IMG_IR_IRQ_ENABLE,
                                        priv->hw.quirk_suspend_irq);
        /* enable */
        img_ir_write(priv, IMG_IR_CONTROL, priv->hw.reg_timings.ctrl);
        spin_unlock_irq(&priv->lock);
}

#ifdef CONFIG_COMMON_CLK
static void img_ir_change_frequency(struct img_ir_priv *priv,
                                    struct clk_notifier_data *change)
{
        struct img_ir_priv_hw *hw = &priv->hw;

        dev_dbg(priv->dev, "clk changed %lu HZ -> %lu HZ\n",
                change->old_rate, change->new_rate);

        spin_lock_irq(&priv->lock);
        if (hw->clk_hz == change->new_rate)
                goto unlock;
        hw->clk_hz = change->new_rate;
        /* refresh current timings */
        if (hw->decoder) {
                img_ir_decoder_convert(hw->decoder, &hw->reg_timings,
                                       hw->clk_hz);
                switch (hw->mode) {
                case IMG_IR_M_NORMAL:
                        img_ir_write_timings(priv, &hw->reg_timings.timings,
                                             RC_FILTER_NORMAL);
                        break;
                case IMG_IR_M_REPEATING:
                        img_ir_write_timings(priv, &hw->reg_timings.rtimings,
                                             RC_FILTER_NORMAL);
                        break;
#ifdef CONFIG_PM_SLEEP
                case IMG_IR_M_WAKE:
                        img_ir_write_timings(priv, &hw->reg_timings.timings,
                                             RC_FILTER_WAKEUP);
                        break;
#endif
                }
        }
unlock:
        spin_unlock_irq(&priv->lock);
}

static int img_ir_clk_notify(struct notifier_block *self, unsigned long action,
                             void *data)
{
        struct img_ir_priv *priv = container_of(self, struct img_ir_priv,
                                                hw.clk_nb);
        switch (action) {
        case POST_RATE_CHANGE:
                img_ir_change_frequency(priv, data);
                break;
        default:
                break;
        }
        return NOTIFY_OK;
}
#endif /* CONFIG_COMMON_CLK */

/* called with priv->lock held */
void img_ir_isr_hw(struct img_ir_priv *priv, u32 irq_status)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        u32 ir_status, len, lw, up;
        unsigned int ct;

        /* use the current decoder */
        if (!hw->decoder)
                return;

        ct = hw->decoder->control.code_type;

        ir_status = img_ir_read(priv, IMG_IR_STATUS);
        if (!(ir_status & (IMG_IR_RXDVAL | IMG_IR_RXDVALD2))) {
                if (!(priv->hw.ct_quirks[ct] & IMG_IR_QUIRK_CODE_IRQ) ||
                                hw->stopping)
                        return;
                /*
                 * The below functionality is added as a work around to stop
                 * multiple Interrupts generated when an incomplete IR code is
                 * received by the decoder.
                 * The decoder generates rapid interrupts without actually
                 * having received any new data. After a single interrupt it's
                 * expected to clear up, but instead multiple interrupts are
                 * rapidly generated. only way to get out of this loop is to
                 * reset the control register after a short delay.
                 */
                img_ir_write(priv, IMG_IR_CONTROL, 0);
                hw->quirk_suspend_irq = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
                img_ir_write(priv, IMG_IR_IRQ_ENABLE,
                             hw->quirk_suspend_irq & IMG_IR_IRQ_EDGE);

                /* Timer activated to re-enable the protocol. */
                mod_timer(&hw->suspend_timer,
                          jiffies + msecs_to_jiffies(5));
                return;
        }
        ir_status &= ~(IMG_IR_RXDVAL | IMG_IR_RXDVALD2);
        img_ir_write(priv, IMG_IR_STATUS, ir_status);

        len = (ir_status & IMG_IR_RXDLEN) >> IMG_IR_RXDLEN_SHIFT;
        /* some versions report wrong length for certain code types */
        if (hw->ct_quirks[ct] & IMG_IR_QUIRK_CODE_LEN_INCR)
                ++len;

        lw = img_ir_read(priv, IMG_IR_DATA_LW);
        up = img_ir_read(priv, IMG_IR_DATA_UP);
        img_ir_handle_data(priv, len, (u64)up << 32 | lw);

}

void img_ir_setup_hw(struct img_ir_priv *priv)
{
        struct img_ir_decoder **decp;

        if (!priv->hw.rdev)
                return;

        /* Use the first available decoder (or disable stuff if NULL) */
        for (decp = img_ir_decoders; *decp; ++decp) {
                const struct img_ir_decoder *dec = *decp;
                if (img_ir_decoder_compatible(priv, dec)) {
                        img_ir_set_protocol(priv, dec->type);
                        img_ir_set_decoder(priv, dec, 0);
                        return;
                }
        }
        img_ir_set_decoder(priv, NULL, 0);
}

/**
 * img_ir_probe_hw_caps() - Probe capabilities of the hardware.
 * @priv:       IR private data.
 */
static void img_ir_probe_hw_caps(struct img_ir_priv *priv)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        /*
         * When a version of the block becomes available without these quirks,
         * they'll have to depend on the core revision.
         */
        hw->ct_quirks[IMG_IR_CODETYPE_PULSELEN]
                |= IMG_IR_QUIRK_CODE_LEN_INCR;
        hw->ct_quirks[IMG_IR_CODETYPE_BIPHASE]
                |= IMG_IR_QUIRK_CODE_IRQ;
        hw->ct_quirks[IMG_IR_CODETYPE_2BITPULSEPOS]
                |= IMG_IR_QUIRK_CODE_BROKEN;
}

int img_ir_probe_hw(struct img_ir_priv *priv)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        struct rc_dev *rdev;
        int error;

        /* Ensure hardware decoders have been preprocessed */
        img_ir_init_decoders();

        /* Probe hardware capabilities */
        img_ir_probe_hw_caps(priv);

        /* Set up the end timer */
        timer_setup(&hw->end_timer, img_ir_end_timer, 0);
        timer_setup(&hw->suspend_timer, img_ir_suspend_timer, 0);

        /* Register a clock notifier */
        if (!IS_ERR(priv->clk)) {
                hw->clk_hz = clk_get_rate(priv->clk);
#ifdef CONFIG_COMMON_CLK
                hw->clk_nb.notifier_call = img_ir_clk_notify;
                error = clk_notifier_register(priv->clk, &hw->clk_nb);
                if (error)
                        dev_warn(priv->dev,
                                 "failed to register clock notifier\n");
#endif
        } else {
                hw->clk_hz = 32768;
        }

        /* Allocate hardware decoder */
        hw->rdev = rdev = rc_allocate_device(RC_DRIVER_SCANCODE);
        if (!rdev) {
                dev_err(priv->dev, "cannot allocate input device\n");
                error = -ENOMEM;
                goto err_alloc_rc;
        }
        rdev->priv = priv;
        rdev->map_name = RC_MAP_EMPTY;
        rdev->allowed_protocols = img_ir_allowed_protos(priv);
        rdev->device_name = "IMG Infrared Decoder";
        rdev->s_filter = img_ir_set_normal_filter;
        rdev->s_wakeup_filter = img_ir_set_wakeup_filter;

        /* Register hardware decoder */
        error = rc_register_device(rdev);
        if (error) {
                dev_err(priv->dev, "failed to register IR input device\n");
                goto err_register_rc;
        }

        /*
         * Set this after rc_register_device as no protocols have been
         * registered yet.
         */
        rdev->change_protocol = img_ir_change_protocol;

        device_init_wakeup(priv->dev, 1);

        return 0;

err_register_rc:
        img_ir_set_decoder(priv, NULL, 0);
        hw->rdev = NULL;
        rc_free_device(rdev);
err_alloc_rc:
#ifdef CONFIG_COMMON_CLK
        if (!IS_ERR(priv->clk))
                clk_notifier_unregister(priv->clk, &hw->clk_nb);
#endif
        return error;
}

void img_ir_remove_hw(struct img_ir_priv *priv)
{
        struct img_ir_priv_hw *hw = &priv->hw;
        struct rc_dev *rdev = hw->rdev;
        if (!rdev)
                return;
        img_ir_set_decoder(priv, NULL, 0);
        hw->rdev = NULL;
        rc_unregister_device(rdev);
#ifdef CONFIG_COMMON_CLK
        if (!IS_ERR(priv->clk))
                clk_notifier_unregister(priv->clk, &hw->clk_nb);
#endif
}

#ifdef CONFIG_PM_SLEEP
int img_ir_suspend(struct device *dev)
{
        struct img_ir_priv *priv = dev_get_drvdata(dev);

        if (device_may_wakeup(dev) && img_ir_enable_wake(priv))
                enable_irq_wake(priv->irq);
        return 0;
}

int img_ir_resume(struct device *dev)
{
        struct img_ir_priv *priv = dev_get_drvdata(dev);

        if (device_may_wakeup(dev) && img_ir_disable_wake(priv))
                disable_irq_wake(priv->irq);
        return 0;
}
#endif  /* CONFIG_PM_SLEEP */