1/*
  2 * dm355evm_keys.c - support buttons and IR remote on DM355 EVM board
  3 *
  4 * Copyright (c) 2008 by David Brownell
  5 *
  6 * This program is free software; you can redistribute it and/or
  7 * modify it under the terms of the GNU General Public License
  8 * as published by the Free Software Foundation; either version
  9 * 2 of the License, or (at your option) any later version.
 10 */
 11#include <linux/kernel.h>
 12#include <linux/slab.h>
 13#include <linux/input.h>
 14#include <linux/input/sparse-keymap.h>
 15#include <linux/platform_device.h>
 16#include <linux/interrupt.h>
 17
 18#include <linux/mfd/dm355evm_msp.h>
 19#include <linux/module.h>
 20
 21
 22/*
 23 * The MSP430 firmware on the DM355 EVM monitors on-board pushbuttons
 24 * and an IR receptor used for the remote control.  When any key is
 25 * pressed, or its autorepeat kicks in, an event is sent.  This driver
 26 * read those events from the small (32 event) queue and reports them.
 27 *
 28 * Note that physically there can only be one of these devices.
 29 *
 30 * This driver was tested with firmware revision A4.
 31 */
 32struct dm355evm_keys {
 33	struct input_dev	*input;
 34	struct device		*dev;
 35};
 36
 37/* These initial keycodes can be remapped */
 38static const struct key_entry dm355evm_keys[] = {
 39	/*
 40	 * Pushbuttons on the EVM board ... note that the labels for these
 41	 * are SW10/SW11/etc on the PC board.  The left/right orientation
 42	 * comes only from the firmware's documentation, and presumes the
 43	 * power connector is immediately in front of you and the IR sensor
 44	 * is to the right.  (That is, rotate the board counter-clockwise
 45	 * by 90 degrees from the SW10/etc and "DM355 EVM" labels.)
 46	 */
 47	{ KE_KEY, 0x00d8, { KEY_OK } },		/* SW12 */
 48	{ KE_KEY, 0x00b8, { KEY_UP } },		/* SW13 */
 49	{ KE_KEY, 0x00e8, { KEY_DOWN } },	/* SW11 */
 50	{ KE_KEY, 0x0078, { KEY_LEFT } },	/* SW14 */
 51	{ KE_KEY, 0x00f0, { KEY_RIGHT } },	/* SW10 */
 52
 53	/*
 54	 * IR buttons ... codes assigned to match the universal remote
 55	 * provided with the EVM (Philips PM4S) using DVD code 0020.
 56	 *
 57	 * These event codes match firmware documentation, but other
 58	 * remote controls could easily send more RC5-encoded events.
 59	 * The PM4S manual was used in several cases to help select
 60	 * a keycode reflecting the intended usage.
 61	 *
 62	 * RC5 codes are 14 bits, with two start bits (0x3 prefix)
 63	 * and a toggle bit (masked out below).
 64	 */
 65	{ KE_KEY, 0x300c, { KEY_POWER } },	/* NOTE: docs omit this */
 66	{ KE_KEY, 0x3000, { KEY_NUMERIC_0 } },
 67	{ KE_KEY, 0x3001, { KEY_NUMERIC_1 } },
 68	{ KE_KEY, 0x3002, { KEY_NUMERIC_2 } },
 69	{ KE_KEY, 0x3003, { KEY_NUMERIC_3 } },
 70	{ KE_KEY, 0x3004, { KEY_NUMERIC_4 } },
 71	{ KE_KEY, 0x3005, { KEY_NUMERIC_5 } },
 72	{ KE_KEY, 0x3006, { KEY_NUMERIC_6 } },
 73	{ KE_KEY, 0x3007, { KEY_NUMERIC_7 } },
 74	{ KE_KEY, 0x3008, { KEY_NUMERIC_8 } },
 75	{ KE_KEY, 0x3009, { KEY_NUMERIC_9 } },
 76	{ KE_KEY, 0x3022, { KEY_ENTER } },
 77	{ KE_KEY, 0x30ec, { KEY_MODE } },	/* "tv/vcr/..." */
 78	{ KE_KEY, 0x300f, { KEY_SELECT } },	/* "info" */
 79	{ KE_KEY, 0x3020, { KEY_CHANNELUP } },	/* "up" */
 80	{ KE_KEY, 0x302e, { KEY_MENU } },	/* "in/out" */
 81	{ KE_KEY, 0x3011, { KEY_VOLUMEDOWN } },	/* "left" */
 82	{ KE_KEY, 0x300d, { KEY_MUTE } },	/* "ok" */
 83	{ KE_KEY, 0x3010, { KEY_VOLUMEUP } },	/* "right" */
 84	{ KE_KEY, 0x301e, { KEY_SUBTITLE } },	/* "cc" */
 85	{ KE_KEY, 0x3021, { KEY_CHANNELDOWN } },/* "down" */
 86	{ KE_KEY, 0x3022, { KEY_PREVIOUS } },
 87	{ KE_KEY, 0x3026, { KEY_SLEEP } },
 88	{ KE_KEY, 0x3172, { KEY_REWIND } },	/* NOTE: docs wrongly say 0x30ca */
 89	{ KE_KEY, 0x3175, { KEY_PLAY } },
 90	{ KE_KEY, 0x3174, { KEY_FASTFORWARD } },
 91	{ KE_KEY, 0x3177, { KEY_RECORD } },
 92	{ KE_KEY, 0x3176, { KEY_STOP } },
 93	{ KE_KEY, 0x3169, { KEY_PAUSE } },
 94};
 95
 96/*
 97 * Because we communicate with the MSP430 using I2C, and all I2C calls
 98 * in Linux sleep, we use a threaded IRQ handler.  The IRQ itself is
 99 * active low, but we go through the GPIO controller so we can trigger
100 * on falling edges and not worry about enabling/disabling the IRQ in
101 * the keypress handling path.
102 */
103static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
104{
105	static u16 last_event;
106	struct dm355evm_keys *keys = _keys;
107	const struct key_entry *ke;
108	unsigned int keycode;
109	int status;
110	u16 event;
111
112	/* For simplicity we ignore INPUT_COUNT and just read
113	 * events until we get the "queue empty" indicator.
114	 * Reading INPUT_LOW decrements the count.
115	 */
116	for (;;) {
117		status = dm355evm_msp_read(DM355EVM_MSP_INPUT_HIGH);
118		if (status < 0) {
119			dev_dbg(keys->dev, "input high err %d\n",
120					status);
121			break;
122		}
123		event = status << 8;
124
125		status = dm355evm_msp_read(DM355EVM_MSP_INPUT_LOW);
126		if (status < 0) {
127			dev_dbg(keys->dev, "input low err %d\n",
128					status);
129			break;
130		}
131		event |= status;
132		if (event == 0xdead)
133			break;
134
135		/* Press and release a button:  two events, same code.
136		 * Press and hold (autorepeat), then release: N events
137		 * (N > 2), same code.  For RC5 buttons the toggle bits
138		 * distinguish (for example) "1-autorepeat" from "1 1";
139		 * but PCB buttons don't support that bit.
140		 *
141		 * So we must synthesize release events.  We do that by
142		 * mapping events to a press/release event pair; then
143		 * to avoid adding extra events, skip the second event
144		 * of each pair.
145		 */
146		if (event == last_event) {
147			last_event = 0;
148			continue;
149		}
150		last_event = event;
151
152		/* ignore the RC5 toggle bit */
153		event &= ~0x0800;
154
155		/* find the key, or report it as unknown */
156		ke = sparse_keymap_entry_from_scancode(keys->input, event);
157		keycode = ke ? ke->keycode : KEY_UNKNOWN;
158		dev_dbg(keys->dev,
159			"input event 0x%04x--> keycode %d\n",
160			event, keycode);
161
162		/* report press + release */
163		input_report_key(keys->input, keycode, 1);
164		input_sync(keys->input);
165		input_report_key(keys->input, keycode, 0);
166		input_sync(keys->input);
167	}
168
169	return IRQ_HANDLED;
170}
171
172/*----------------------------------------------------------------------*/
173
174static int dm355evm_keys_probe(struct platform_device *pdev)
175{
176	struct dm355evm_keys	*keys;
177	struct input_dev	*input;
178	int			irq;
179	int			error;
180
181	keys = devm_kzalloc(&pdev->dev, sizeof (*keys), GFP_KERNEL);
182	if (!keys)
183		return -ENOMEM;
184
185	input = devm_input_allocate_device(&pdev->dev);
186	if (!input)
187		return -ENOMEM;
188
189	keys->dev = &pdev->dev;
190	keys->input = input;
191
192	input->name = "DM355 EVM Controls";
193	input->phys = "dm355evm/input0";
194
195	input->id.bustype = BUS_I2C;
196	input->id.product = 0x0355;
197	input->id.version = dm355evm_msp_read(DM355EVM_MSP_FIRMREV);
198
199	error = sparse_keymap_setup(input, dm355evm_keys, NULL);
200	if (error)
201		return error;
202
203	/* REVISIT:  flush the event queue? */
204
205	/* set up "threaded IRQ handler" */
206	irq = platform_get_irq(pdev, 0);
207	if (irq < 0)
208		return irq;
209
210	error = devm_request_threaded_irq(&pdev->dev, irq,
211					  NULL, dm355evm_keys_irq,
212					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
213					  dev_name(&pdev->dev), keys);
214	if (error)
215		return error;
216
217	/* register */
218	error = input_register_device(input);
219	if (error)
220		return error;
221
222	return 0;
223}
224
225/* REVISIT:  add suspend/resume when DaVinci supports it.  The IRQ should
226 * be able to wake up the system.  When device_may_wakeup(&pdev->dev), call
227 * enable_irq_wake() on suspend, and disable_irq_wake() on resume.
228 */
229
230/*
231 * I2C is used to talk to the MSP430, but this platform device is
232 * exposed by an MFD driver that manages I2C communications.
233 */
234static struct platform_driver dm355evm_keys_driver = {
235	.probe		= dm355evm_keys_probe,
236	.driver		= {
237		.name	= "dm355evm_keys",
238	},
239};
240module_platform_driver(dm355evm_keys_driver);
241
242MODULE_LICENSE("GPL");