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");