Input: add dm355evm_keys driver

Simple input driver support for the events reported by the
MSP430 firmware on the DM355 EVM.  Verified using the RC5
remote included with the kit; docs weren't quite right.

Some of the keycode selections might need improvement; they
can be remapped, so there's at least a runtime workaround.
(I also suspect Linux may someday merit more generic support
for RC5 based remote controls.)

These events don't distinguish key press vs release events,
so this reports both and then skips the next event if it's
identical.  The RC5 remote codes include a "toggle" bit that
can help detect autorepeated keys; but this driver doesn't
bother with those nuances.

This driver relies on the drivers/mfd/dm355evm_msp.c code
for core features, including sharing I2C access to this
firmware with GPIO, LED, and RTC support.

[dtor@mail.ru: fix error unwindng path in probe()]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/misc/Kconfig

@@ -260,4 +260,13 @@ config INPUT_RB532_BUTTON
 	  To compile this driver as a module, choose M here: the
 	  module will be called rb532_button.
 
+config INPUT_DM355EVM
+	tristate "TI DaVinci DM355 EVM Keypad and IR Remote"
+	depends on MFD_DM355EVM_MSP
+	help
+	  Supports the pushbuttons and IR remote used with
+	  the DM355 EVM board.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called dm355evm_keys.
 endif

drivers/input/misc/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_INPUT_ATI_REMOTE2)		+= ati_remote2.o
 obj-$(CONFIG_INPUT_ATLAS_BTNS)		+= atlas_btns.o
 obj-$(CONFIG_INPUT_CM109)		+= cm109.o
 obj-$(CONFIG_INPUT_COBALT_BTNS)		+= cobalt_btns.o
+obj-$(CONFIG_INPUT_DM355EVM)		+= dm355evm_keys.o
 obj-$(CONFIG_HP_SDC_RTC)		+= hp_sdc_rtc.o
 obj-$(CONFIG_INPUT_IXP4XX_BEEPER)	+= ixp4xx-beeper.o
 obj-$(CONFIG_INPUT_KEYSPAN_REMOTE)	+= keyspan_remote.o

drivers/input/misc/dm355evm_keys.c

+/*
+ * 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/init.h>
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+
+#include <linux/i2c/dm355evm_msp.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.
+ *
+ * Because we communicate with the MSP430 using I2C, and all I2C calls
+ * in Linux sleep, we need to cons up a kind of threaded IRQ handler
+ * using a work_struct.  The IRQ is active low, but we use it through
+ * the GPIO controller so we can trigger on falling edges.
+ *
+ * Note that physically there can only be one of these devices.
+ *
+ * This driver was tested with firmware revision A4.
+ */
+struct dm355evm_keys {
+	struct work_struct	work;
+	struct input_dev	*input;
+	struct device		*dev;
+	int			irq;
+};
+
+static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
+{
+	struct dm355evm_keys	*keys = _keys;
+
+	schedule_work(&keys->work);
+	return IRQ_HANDLED;
+}
+
+/* These initial keycodes can be remapped by dm355evm_setkeycode(). */
+static struct {
+	u16	event;
+	u16	keycode;
+} 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.)
+	 */
+	{ 0x00d8, KEY_OK, },		/* SW12 */
+	{ 0x00b8, KEY_UP, },		/* SW13 */
+	{ 0x00e8, KEY_DOWN, },		/* SW11 */
+	{ 0x0078, KEY_LEFT, },		/* SW14 */
+	{ 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).
+	 */
+	{ 0x300c, KEY_POWER, },		/* NOTE: docs omit this */
+	{ 0x3000, KEY_NUMERIC_0, },
+	{ 0x3001, KEY_NUMERIC_1, },
+	{ 0x3002, KEY_NUMERIC_2, },
+	{ 0x3003, KEY_NUMERIC_3, },
+	{ 0x3004, KEY_NUMERIC_4, },
+	{ 0x3005, KEY_NUMERIC_5, },
+	{ 0x3006, KEY_NUMERIC_6, },
+	{ 0x3007, KEY_NUMERIC_7, },
+	{ 0x3008, KEY_NUMERIC_8, },
+	{ 0x3009, KEY_NUMERIC_9, },
+	{ 0x3022, KEY_ENTER, },
+	{ 0x30ec, KEY_MODE, },		/* "tv/vcr/..." */
+	{ 0x300f, KEY_SELECT, },	/* "info" */
+	{ 0x3020, KEY_CHANNELUP, },	/* "up" */
+	{ 0x302e, KEY_MENU, },		/* "in/out" */
+	{ 0x3011, KEY_VOLUMEDOWN, },	/* "left" */
+	{ 0x300d, KEY_MUTE, },		/* "ok" */
+	{ 0x3010, KEY_VOLUMEUP, },	/* "right" */
+	{ 0x301e, KEY_SUBTITLE, },	/* "cc" */
+	{ 0x3021, KEY_CHANNELDOWN, },	/* "down" */
+	{ 0x3022, KEY_PREVIOUS, },
+	{ 0x3026, KEY_SLEEP, },
+	{ 0x3172, KEY_REWIND, },	/* NOTE: docs wrongly say 0x30ca */
+	{ 0x3175, KEY_PLAY, },
+	{ 0x3174, KEY_FASTFORWARD, },
+	{ 0x3177, KEY_RECORD, },
+	{ 0x3176, KEY_STOP, },
+	{ 0x3169, KEY_PAUSE, },
+};
+
+static void dm355evm_keys_work(struct work_struct *work)
+{
+	struct dm355evm_keys	*keys;
+	int			status;
+
+	keys = container_of(work, struct dm355evm_keys, work);
+
+	/* For simplicity we ignore INPUT_COUNT and just read
+	 * events until we get the "queue empty" indicator.
+	 * Reading INPUT_LOW decrements the count.
+	 */
+	for (;;) {
+		static u16	last_event;
+		u16		event;
+		int		keycode;
+		int		i;
+
+		status = dm355evm_msp_read(DM355EVM_MSP_INPUT_HIGH);
+		if (status < 0) {
+			dev_dbg(keys->dev, "input high err %d\n",
+					status);
+			break;
+		}
+		event = status << 8;
+
+		status = dm355evm_msp_read(DM355EVM_MSP_INPUT_LOW);
+		if (status < 0) {
+			dev_dbg(keys->dev, "input low err %d\n",
+					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 leave it as unknown */
+		keycode = KEY_UNKNOWN;
+		for (i = 0; i < ARRAY_SIZE(dm355evm_keys); i++) {
+			if (dm355evm_keys[i].event != event)
+				continue;
+			keycode = dm355evm_keys[i].keycode;
+			break;
+		}
+		dev_dbg(keys->dev,
+			"input event 0x%04x--> keycode %d\n",
+			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);
+	}
+}
+
+static int dm355evm_setkeycode(struct input_dev *dev, int index, int keycode)
+{
+	u16		old_keycode;
+	unsigned	i;
+
+	if (((unsigned)index) >= ARRAY_SIZE(dm355evm_keys))
+		return -EINVAL;
+
+	old_keycode = dm355evm_keys[index].keycode;
+	dm355evm_keys[index].keycode = keycode;
+	set_bit(keycode, dev->keybit);
+
+	for (i = 0; i < ARRAY_SIZE(dm355evm_keys); i++) {
+		if (dm355evm_keys[index].keycode == old_keycode)
+			goto done;
+	}
+	clear_bit(old_keycode, dev->keybit);
+done:
+	return 0;
+}
+
+static int dm355evm_getkeycode(struct input_dev *dev, int index, int *keycode)
+{
+	if (((unsigned)index) >= ARRAY_SIZE(dm355evm_keys))
+		return -EINVAL;
+
+	return dm355evm_keys[index].keycode;
+}
+
+/*----------------------------------------------------------------------*/
+
+static int __devinit dm355evm_keys_probe(struct platform_device *pdev)
+{
+	struct dm355evm_keys	*keys;
+	struct input_dev	*input;
+	int			status;
+	int			i;
+
+	/* 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;
+	INIT_WORK(&keys->work, dm355evm_keys_work);
+
+	/* 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);
+
+	input->evbit[0] = BIT(EV_KEY);
+	for (i = 0; i < ARRAY_SIZE(dm355evm_keys); i++)
+		__set_bit(dm355evm_keys[i].keycode, input->keybit);
+
+	input->setkeycode = dm355evm_setkeycode;
+	input->getkeycode = dm355evm_getkeycode;
+
+	/* REVISIT:  flush the event queue? */
+
+	status = request_irq(keys->irq, dm355evm_keys_irq,
+			     IRQF_TRIGGER_FALLING,
+			     dev_name(&pdev->dev), keys);
+	if (status < 0)
+		goto fail1;
+
+	/* register */
+	status = input_register_device(input);
+	if (status < 0)
+		goto fail2;
+
+	platform_set_drvdata(pdev, keys);
+
+	return 0;
+
+fail2:
+	free_irq(keys->irq, keys);
+fail1:
+	input_free_device(input);
+	kfree(keys);
+	dev_err(&pdev->dev, "can't register, err %d\n", status);
+
+	return status;
+}
+
+static int __devexit dm355evm_keys_remove(struct platform_device *pdev)
+{
+	struct dm355evm_keys	*keys = platform_get_drvdata(pdev);
+
+	free_irq(keys->irq, keys);
+	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		= __devexit_p(dm355evm_keys_remove),
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "dm355evm_keys",
+	},
+};
+
+static int __init dm355evm_keys_init(void)
+{
+	return platform_driver_register(&dm355evm_keys_driver);
+}
+module_init(dm355evm_keys_init);
+
+static void __exit dm355evm_keys_exit(void)
+{
+	platform_driver_unregister(&dm355evm_keys_driver);
+}
+module_exit(dm355evm_keys_exit);
+
+MODULE_LICENSE("GPL");