drivers/input/misc/dm355evm_keys.c

   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  */
  28 struct dm355evm_keys {
  29         struct input_dev        *input;
  30         struct device           *dev;
  31 };
  32
  33 /* These initial keycodes can be remapped */
  34 static 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  */
  99 static 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
 170 static 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  */
 230 static struct platform_driver dm355evm_keys_driver = {
 231         .probe          = dm355evm_keys_probe,
 232         .driver         = {
 233                 .name   = "dm355evm_keys",
 234         },
 235 };
 236 module_platform_driver(dm355evm_keys_driver);
 237
 238 MODULE_LICENSE("GPL");