/*
   * dm355evm_keys.c - support buttons and IR remote on DM355 EVM board
   *
   * Copyright (c) 2008 by David Brownell
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/input.h>
  #include <linux/input/sparse-keymap.h>
  #include <linux/platform_device.h>
  #include <linux/interrupt.h>
  
  #include <linux/i2c/dm355evm_msp.h>
  #include <linux/module.h>
  
  
  /*
   * The MSP430 firmware on the DM355 EVM monitors on-board pushbuttons
   * and an IR receptor used for the remote control.  When any key is
   * pressed, or its autorepeat kicks in, an event is sent.  This driver
   * read those events from the small (32 event) queue and reports them.
   *
   * Note that physically there can only be one of these devices.
   *
   * This driver was tested with firmware revision A4.
   */
  struct dm355evm_keys {
  	struct input_dev	*input;
  	struct device		*dev;
  	int			irq;
  };
  
  /* These initial keycodes can be remapped */
  static const struct key_entry dm355evm_keys[] = {
  	/*
  	 * Pushbuttons on the EVM board ... note that the labels for these
  	 * are SW10/SW11/etc on the PC board.  The left/right orientation
  	 * comes only from the firmware's documentation, and presumes the
  	 * power connector is immediately in front of you and the IR sensor
  	 * is to the right.  (That is, rotate the board counter-clockwise
  	 * by 90 degrees from the SW10/etc and "DM355 EVM" labels.)
  	 */
  	{ KE_KEY, 0x00d8, { KEY_OK } },		/* SW12 */
  	{ KE_KEY, 0x00b8, { KEY_UP } },		/* SW13 */
  	{ KE_KEY, 0x00e8, { KEY_DOWN } },	/* SW11 */
  	{ KE_KEY, 0x0078, { KEY_LEFT } },	/* SW14 */
  	{ KE_KEY, 0x00f0, { KEY_RIGHT } },	/* SW10 */
  
  	/*
  	 * IR buttons ... codes assigned to match the universal remote
  	 * provided with the EVM (Philips PM4S) using DVD code 0020.
  	 *
  	 * These event codes match firmware documentation, but other
  	 * remote controls could easily send more RC5-encoded events.
  	 * The PM4S manual was used in several cases to help select
  	 * a keycode reflecting the intended usage.
  	 *
  	 * RC5 codes are 14 bits, with two start bits (0x3 prefix)
  	 * and a toggle bit (masked out below).
  	 */
  	{ KE_KEY, 0x300c, { KEY_POWER } },	/* NOTE: docs omit this */
  	{ KE_KEY, 0x3000, { KEY_NUMERIC_0 } },
  	{ KE_KEY, 0x3001, { KEY_NUMERIC_1 } },
  	{ KE_KEY, 0x3002, { KEY_NUMERIC_2 } },
  	{ KE_KEY, 0x3003, { KEY_NUMERIC_3 } },
  	{ KE_KEY, 0x3004, { KEY_NUMERIC_4 } },
  	{ KE_KEY, 0x3005, { KEY_NUMERIC_5 } },
  	{ KE_KEY, 0x3006, { KEY_NUMERIC_6 } },
  	{ KE_KEY, 0x3007, { KEY_NUMERIC_7 } },
  	{ KE_KEY, 0x3008, { KEY_NUMERIC_8 } },
  	{ KE_KEY, 0x3009, { KEY_NUMERIC_9 } },
  	{ KE_KEY, 0x3022, { KEY_ENTER } },
  	{ KE_KEY, 0x30ec, { KEY_MODE } },	/* "tv/vcr/..." */
  	{ KE_KEY, 0x300f, { KEY_SELECT } },	/* "info" */
  	{ KE_KEY, 0x3020, { KEY_CHANNELUP } },	/* "up" */
  	{ KE_KEY, 0x302e, { KEY_MENU } },	/* "in/out" */
  	{ KE_KEY, 0x3011, { KEY_VOLUMEDOWN } },	/* "left" */
  	{ KE_KEY, 0x300d, { KEY_MUTE } },	/* "ok" */
  	{ KE_KEY, 0x3010, { KEY_VOLUMEUP } },	/* "right" */
  	{ KE_KEY, 0x301e, { KEY_SUBTITLE } },	/* "cc" */
  	{ KE_KEY, 0x3021, { KEY_CHANNELDOWN } },/* "down" */
  	{ KE_KEY, 0x3022, { KEY_PREVIOUS } },
  	{ KE_KEY, 0x3026, { KEY_SLEEP } },
  	{ KE_KEY, 0x3172, { KEY_REWIND } },	/* NOTE: docs wrongly say 0x30ca */
  	{ KE_KEY, 0x3175, { KEY_PLAY } },
  	{ KE_KEY, 0x3174, { KEY_FASTFORWARD } },
  	{ KE_KEY, 0x3177, { KEY_RECORD } },
  	{ KE_KEY, 0x3176, { KEY_STOP } },
  	{ KE_KEY, 0x3169, { KEY_PAUSE } },
  };
  
  /*
   * Because we communicate with the MSP430 using I2C, and all I2C calls
   * in Linux sleep, we use a threaded IRQ handler.  The IRQ itself is
   * active low, but we go through the GPIO controller so we can trigger
   * on falling edges and not worry about enabling/disabling the IRQ in
   * the keypress handling path.
   */
  static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
  {
  	static u16 last_event;
  	struct dm355evm_keys *keys = _keys;
  	const struct key_entry *ke;
  	unsigned int keycode;
  	int status;
  	u16 event;
  
  	/* For simplicity we ignore INPUT_COUNT and just read
  	 * events until we get the "queue empty" indicator.
  	 * Reading INPUT_LOW decrements the count.
  	 */
  	for (;;) {
  		status = dm355evm_msp_read(DM355EVM_MSP_INPUT_HIGH);
  		if (status < 0) {
  			dev_dbg(keys->dev, "input high err %d
  ",
  					status);
  			break;
  		}
  		event = status << 8;
  
  		status = dm355evm_msp_read(DM355EVM_MSP_INPUT_LOW);
  		if (status < 0) {
  			dev_dbg(keys->dev, "input low err %d
  ",
  					status);
  			break;
  		}
  		event |= status;
  		if (event == 0xdead)
  			break;
  
  		/* Press and release a button:  two events, same code.
  		 * Press and hold (autorepeat), then release: N events
  		 * (N > 2), same code.  For RC5 buttons the toggle bits
  		 * distinguish (for example) "1-autorepeat" from "1 1";
  		 * but PCB buttons don't support that bit.
  		 *
  		 * So we must synthesize release events.  We do that by
  		 * mapping events to a press/release event pair; then
  		 * to avoid adding extra events, skip the second event
  		 * of each pair.
  		 */
  		if (event == last_event) {
  			last_event = 0;
  			continue;
  		}
  		last_event = event;
  
  		/* ignore the RC5 toggle bit */
  		event &= ~0x0800;
  
  		/* find the key, or report it as unknown */
  		ke = sparse_keymap_entry_from_scancode(keys->input, event);
  		keycode = ke ? ke->keycode : KEY_UNKNOWN;
  		dev_dbg(keys->dev,
  			"input event 0x%04x--> keycode %d
  ",
  			event, keycode);
  
  		/* report press + release */
  		input_report_key(keys->input, keycode, 1);
  		input_sync(keys->input);
  		input_report_key(keys->input, keycode, 0);
  		input_sync(keys->input);
  	}
  
  	return IRQ_HANDLED;
  }
  
  /*----------------------------------------------------------------------*/
  
  static int dm355evm_keys_probe(struct platform_device *pdev)
  {
  	struct dm355evm_keys	*keys;
  	struct input_dev	*input;
  	int			status;
  
  	/* allocate instance struct and input dev */
  	keys = kzalloc(sizeof *keys, GFP_KERNEL);
  	input = input_allocate_device();
  	if (!keys || !input) {
  		status = -ENOMEM;
  		goto fail1;
  	}
  
  	keys->dev = &pdev->dev;
  	keys->input = input;
  
  	/* set up "threaded IRQ handler" */
  	status = platform_get_irq(pdev, 0);
  	if (status < 0)
  		goto fail1;
  	keys->irq = status;
  
  	input_set_drvdata(input, keys);
  
  	input->name = "DM355 EVM Controls";
  	input->phys = "dm355evm/input0";
  	input->dev.parent = &pdev->dev;
  
  	input->id.bustype = BUS_I2C;
  	input->id.product = 0x0355;
  	input->id.version = dm355evm_msp_read(DM355EVM_MSP_FIRMREV);
  
  	status = sparse_keymap_setup(input, dm355evm_keys, NULL);
  	if (status)
  		goto fail1;
  
  	/* REVISIT:  flush the event queue? */
  
  	status = request_threaded_irq(keys->irq, NULL, dm355evm_keys_irq,
  				      IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
  				      dev_name(&pdev->dev), keys);
  	if (status < 0)
  		goto fail2;
  
  	/* register */
  	status = input_register_device(input);
  	if (status < 0)
  		goto fail3;
  
  	platform_set_drvdata(pdev, keys);
  
  	return 0;
  
  fail3:
  	free_irq(keys->irq, keys);
  fail2:
  	sparse_keymap_free(input);
  fail1:
  	input_free_device(input);
  	kfree(keys);
  	dev_err(&pdev->dev, "can't register, err %d
  ", status);
  
  	return status;
  }
  
  static int dm355evm_keys_remove(struct platform_device *pdev)
  {
  	struct dm355evm_keys	*keys = platform_get_drvdata(pdev);
  
  	free_irq(keys->irq, keys);
  	sparse_keymap_free(keys->input);
  	input_unregister_device(keys->input);
  	kfree(keys);
  
  	return 0;
  }
  
  /* REVISIT:  add suspend/resume when DaVinci supports it.  The IRQ should
   * be able to wake up the system.  When device_may_wakeup(&pdev->dev), call
   * enable_irq_wake() on suspend, and disable_irq_wake() on resume.
   */
  
  /*
   * I2C is used to talk to the MSP430, but this platform device is
   * exposed by an MFD driver that manages I2C communications.
   */
  static struct platform_driver dm355evm_keys_driver = {
  	.probe		= dm355evm_keys_probe,
  	.remove		= dm355evm_keys_remove,
  	.driver		= {
  		.name	= "dm355evm_keys",
  	},
  };
  module_platform_driver(dm355evm_keys_driver);
  
  MODULE_LICENSE("GPL");