linux/drivers/input/misc/dm355evm_keys.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * dm355evm_keys.c - support buttons and IR remote on DM355 EVM board
   4 *
   5 * Copyright (c) 2008 by David Brownell
   6 */
   7#include <linux/kernel.h>
   8#include <linux/slab.h>
   9#include <linux/input.h>
  10#include <linux/input/sparse-keymap.h>
  11#include <linux/platform_device.h>
  12#include <linux/interrupt.h>
  13
  14#include <linux/mfd/dm355evm_msp.h>
  15#include <linux/module.h>
  16
  17
  18/*
  19 * The MSP430 firmware on the DM355 EVM monitors on-board pushbuttons
  20 * and an IR receptor used for the remote control.  When any key is
  21 * pressed, or its autorepeat kicks in, an event is sent.  This driver
  22 * read those events from the small (32 event) queue and reports them.
  23 *
  24 * Note that physically there can only be one of these devices.
  25 *
  26 * This driver was tested with firmware revision A4.
  27 */
  28struct dm355evm_keys {
  29        struct input_dev        *input;
  30        struct device           *dev;
  31};
  32
  33/* These initial keycodes can be remapped */
  34static const struct key_entry dm355evm_keys[] = {
  35        /*
  36         * Pushbuttons on the EVM board ... note that the labels for these
  37         * are SW10/SW11/etc on the PC board.  The left/right orientation
  38         * comes only from the firmware's documentation, and presumes the
  39         * power connector is immediately in front of you and the IR sensor
  40         * is to the right.  (That is, rotate the board counter-clockwise
  41         * by 90 degrees from the SW10/etc and "DM355 EVM" labels.)
  42         */
  43        { KE_KEY, 0x00d8, { KEY_OK } },         /* SW12 */
  44        { KE_KEY, 0x00b8, { KEY_UP } },         /* SW13 */
  45        { KE_KEY, 0x00e8, { KEY_DOWN } },       /* SW11 */
  46        { KE_KEY, 0x0078, { KEY_LEFT } },       /* SW14 */
  47        { KE_KEY, 0x00f0, { KEY_RIGHT } },      /* SW10 */
  48
  49        /*
  50         * IR buttons ... codes assigned to match the universal remote
  51         * provided with the EVM (Philips PM4S) using DVD code 0020.
  52         *
  53         * These event codes match firmware documentation, but other
  54         * remote controls could easily send more RC5-encoded events.
  55         * The PM4S manual was used in several cases to help select
  56         * a keycode reflecting the intended usage.
  57         *
  58         * RC5 codes are 14 bits, with two start bits (0x3 prefix)
  59         * and a toggle bit (masked out below).
  60         */
  61        { KE_KEY, 0x300c, { KEY_POWER } },      /* NOTE: docs omit this */
  62        { KE_KEY, 0x3000, { KEY_NUMERIC_0 } },
  63        { KE_KEY, 0x3001, { KEY_NUMERIC_1 } },
  64        { KE_KEY, 0x3002, { KEY_NUMERIC_2 } },
  65        { KE_KEY, 0x3003, { KEY_NUMERIC_3 } },
  66        { KE_KEY, 0x3004, { KEY_NUMERIC_4 } },
  67        { KE_KEY, 0x3005, { KEY_NUMERIC_5 } },
  68        { KE_KEY, 0x3006, { KEY_NUMERIC_6 } },
  69        { KE_KEY, 0x3007, { KEY_NUMERIC_7 } },
  70        { KE_KEY, 0x3008, { KEY_NUMERIC_8 } },
  71        { KE_KEY, 0x3009, { KEY_NUMERIC_9 } },
  72        { KE_KEY, 0x3022, { KEY_ENTER } },
  73        { KE_KEY, 0x30ec, { KEY_MODE } },       /* "tv/vcr/..." */
  74        { KE_KEY, 0x300f, { KEY_SELECT } },     /* "info" */
  75        { KE_KEY, 0x3020, { KEY_CHANNELUP } },  /* "up" */
  76        { KE_KEY, 0x302e, { KEY_MENU } },       /* "in/out" */
  77        { KE_KEY, 0x3011, { KEY_VOLUMEDOWN } }, /* "left" */
  78        { KE_KEY, 0x300d, { KEY_MUTE } },       /* "ok" */
  79        { KE_KEY, 0x3010, { KEY_VOLUMEUP } },   /* "right" */
  80        { KE_KEY, 0x301e, { KEY_SUBTITLE } },   /* "cc" */
  81        { KE_KEY, 0x3021, { KEY_CHANNELDOWN } },/* "down" */
  82        { KE_KEY, 0x3022, { KEY_PREVIOUS } },
  83        { KE_KEY, 0x3026, { KEY_SLEEP } },
  84        { KE_KEY, 0x3172, { KEY_REWIND } },     /* NOTE: docs wrongly say 0x30ca */
  85        { KE_KEY, 0x3175, { KEY_PLAY } },
  86        { KE_KEY, 0x3174, { KEY_FASTFORWARD } },
  87        { KE_KEY, 0x3177, { KEY_RECORD } },
  88        { KE_KEY, 0x3176, { KEY_STOP } },
  89        { KE_KEY, 0x3169, { KEY_PAUSE } },
  90};
  91
  92/*
  93 * Because we communicate with the MSP430 using I2C, and all I2C calls
  94 * in Linux sleep, we use a threaded IRQ handler.  The IRQ itself is
  95 * active low, but we go through the GPIO controller so we can trigger
  96 * on falling edges and not worry about enabling/disabling the IRQ in
  97 * the keypress handling path.
  98 */
  99static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
 100{
 101        static u16 last_event;
 102        struct dm355evm_keys *keys = _keys;
 103        const struct key_entry *ke;
 104        unsigned int keycode;
 105        int status;
 106        u16 event;
 107
 108        /* For simplicity we ignore INPUT_COUNT and just read
 109         * events until we get the "queue empty" indicator.
 110         * Reading INPUT_LOW decrements the count.
 111         */
 112        for (;;) {
 113                status = dm355evm_msp_read(DM355EVM_MSP_INPUT_HIGH);
 114                if (status < 0) {
 115                        dev_dbg(keys->dev, "input high err %d\n",
 116                                        status);
 117                        break;
 118                }
 119                event = status << 8;
 120
 121                status = dm355evm_msp_read(DM355EVM_MSP_INPUT_LOW);
 122                if (status < 0) {
 123                        dev_dbg(keys->dev, "input low err %d\n",
 124                                        status);
 125                        break;
 126                }
 127                event |= status;
 128                if (event == 0xdead)
 129                        break;
 130
 131                /* Press and release a button:  two events, same code.
 132                 * Press and hold (autorepeat), then release: N events
 133                 * (N > 2), same code.  For RC5 buttons the toggle bits
 134                 * distinguish (for example) "1-autorepeat" from "1 1";
 135                 * but PCB buttons don't support that bit.
 136                 *
 137                 * So we must synthesize release events.  We do that by
 138                 * mapping events to a press/release event pair; then
 139                 * to avoid adding extra events, skip the second event
 140                 * of each pair.
 141                 */
 142                if (event == last_event) {
 143                        last_event = 0;
 144                        continue;
 145                }
 146                last_event = event;
 147
 148                /* ignore the RC5 toggle bit */
 149                event &= ~0x0800;
 150
 151                /* find the key, or report it as unknown */
 152                ke = sparse_keymap_entry_from_scancode(keys->input, event);
 153                keycode = ke ? ke->keycode : KEY_UNKNOWN;
 154                dev_dbg(keys->dev,
 155                        "input event 0x%04x--> keycode %d\n",
 156                        event, keycode);
 157
 158                /* report press + release */
 159                input_report_key(keys->input, keycode, 1);
 160                input_sync(keys->input);
 161                input_report_key(keys->input, keycode, 0);
 162                input_sync(keys->input);
 163        }
 164
 165        return IRQ_HANDLED;
 166}
 167
 168/*----------------------------------------------------------------------*/
 169
 170static int dm355evm_keys_probe(struct platform_device *pdev)
 171{
 172        struct dm355evm_keys    *keys;
 173        struct input_dev        *input;
 174        int                     irq;
 175        int                     error;
 176
 177        keys = devm_kzalloc(&pdev->dev, sizeof (*keys), GFP_KERNEL);
 178        if (!keys)
 179                return -ENOMEM;
 180
 181        input = devm_input_allocate_device(&pdev->dev);
 182        if (!input)
 183                return -ENOMEM;
 184
 185        keys->dev = &pdev->dev;
 186        keys->input = input;
 187
 188        input->name = "DM355 EVM Controls";
 189        input->phys = "dm355evm/input0";
 190
 191        input->id.bustype = BUS_I2C;
 192        input->id.product = 0x0355;
 193        input->id.version = dm355evm_msp_read(DM355EVM_MSP_FIRMREV);
 194
 195        error = sparse_keymap_setup(input, dm355evm_keys, NULL);
 196        if (error)
 197                return error;
 198
 199        /* REVISIT:  flush the event queue? */
 200
 201        /* set up "threaded IRQ handler" */
 202        irq = platform_get_irq(pdev, 0);
 203        if (irq < 0)
 204                return irq;
 205
 206        error = devm_request_threaded_irq(&pdev->dev, irq,
 207                                          NULL, dm355evm_keys_irq,
 208                                          IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 209                                          dev_name(&pdev->dev), keys);
 210        if (error)
 211                return error;
 212
 213        /* register */
 214        error = input_register_device(input);
 215        if (error)
 216                return error;
 217
 218        return 0;
 219}
 220
 221/* REVISIT:  add suspend/resume when DaVinci supports it.  The IRQ should
 222 * be able to wake up the system.  When device_may_wakeup(&pdev->dev), call
 223 * enable_irq_wake() on suspend, and disable_irq_wake() on resume.
 224 */
 225
 226/*
 227 * I2C is used to talk to the MSP430, but this platform device is
 228 * exposed by an MFD driver that manages I2C communications.
 229 */
 230static struct platform_driver dm355evm_keys_driver = {
 231        .probe          = dm355evm_keys_probe,
 232        .driver         = {
 233                .name   = "dm355evm_keys",
 234        },
 235};
 236module_platform_driver(dm355evm_keys_driver);
 237
 238MODULE_LICENSE("GPL");
 239