litmus-rt-tegra.git - LITMUS^RT and MC^2 V0 support for the NVIDIA Tegra 3 SoC

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Diffstat (limited to 'drivers/char/mxser.c')

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1 files changed, 2 insertions, 1 deletions


diff --git a/drivers/char/mxser.c b/drivers/char/mxser.c index 8beef50f95a..04776691541 100644 --- a/drivers/char/mxser.c +++ b/drivers/char/mxser.c
@@ -14,7 +14,8 @@
14	* (at your option) any later version.	14	* (at your option) any later version.
15	*	15	*
16	* Fed through a cleanup, indent and remove of non 2.6 code by Alan Cox	16	* Fed through a cleanup, indent and remove of non 2.6 code by Alan Cox
17	* <alan@redhat.com>. The original 1.8 code is available on www.moxa.com.	17	* <alan@lxorguk.ukuu.org.uk>. The original 1.8 code is available on
		18	* www.moxa.com.
18	* - Fixed x86_64 cleanness	19	* - Fixed x86_64 cleanness
19	*/	20	*/
20		21

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/*
 * Driver for keys on GPIO lines capable of generating interrupts.
 *
 * Copyright 2005 Phil Blundell
 * Copyright 2010, 2011 David Jander <david@protonic.nl>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/gpio_keys.h>
#include <linux/workqueue.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/spinlock.h>

struct gpio_button_data {
	const struct gpio_keys_button *button;
	struct input_dev *input;
	struct gpio_desc *gpiod;

	unsigned short *code;

	struct timer_list release_timer;
	unsigned int release_delay;	/* in msecs, for IRQ-only buttons */

	struct delayed_work work;
	unsigned int software_debounce;	/* in msecs, for GPIO-driven buttons */

	unsigned int irq;
	spinlock_t lock;
	bool disabled;
	bool key_pressed;
};

struct gpio_keys_drvdata {
	const struct gpio_keys_platform_data *pdata;
	struct input_dev *input;
	struct mutex disable_lock;
	unsigned short *keymap;
	struct gpio_button_data data[0];
};

/*
 * SYSFS interface for enabling/disabling keys and switches:
 *
 * There are 4 attributes under /sys/devices/platform/gpio-keys/
 *	keys [ro]              - bitmap of keys (EV_KEY) which can be
 *	                         disabled
 *	switches [ro]          - bitmap of switches (EV_SW) which can be
 *	                         disabled
 *	disabled_keys [rw]     - bitmap of keys currently disabled
 *	disabled_switches [rw] - bitmap of switches currently disabled
 *
 * Userland can change these values and hence disable event generation
 * for each key (or switch). Disabling a key means its interrupt line
 * is disabled.
 *
 * For example, if we have following switches set up as gpio-keys:
 *	SW_DOCK = 5
 *	SW_CAMERA_LENS_COVER = 9
 *	SW_KEYPAD_SLIDE = 10
 *	SW_FRONT_PROXIMITY = 11
 * This is read from switches:
 *	11-9,5
 * Next we want to disable proximity (11) and dock (5), we write:
 *	11,5
 * to file disabled_switches. Now proximity and dock IRQs are disabled.
 * This can be verified by reading the file disabled_switches:
 *	11,5
 * If we now want to enable proximity (11) switch we write:
 *	5
 * to disabled_switches.
 *
 * We can disable only those keys which don't allow sharing the irq.
 */

/**
 * get_n_events_by_type() - returns maximum number of events per @type
 * @type: type of button (%EV_KEY, %EV_SW)
 *
 * Return value of this function can be used to allocate bitmap
 * large enough to hold all bits for given type.
 */
static int get_n_events_by_type(int type)
{
	BUG_ON(type != EV_SW && type != EV_KEY);

	return (type == EV_KEY) ? KEY_CNT : SW_CNT;
}

/**
 * get_bm_events_by_type() - returns bitmap of supported events per @type
 * @input: input device from which bitmap is retrieved
 * @type: type of button (%EV_KEY, %EV_SW)
 *
 * Return value of this function can be used to allocate bitmap
 * large enough to hold all bits for given type.
 */
static const unsigned long *get_bm_events_by_type(struct input_dev *dev,
						  int type)
{
	BUG_ON(type != EV_SW && type != EV_KEY);

	return (type == EV_KEY) ? dev->keybit : dev->swbit;
}

/**
 * gpio_keys_disable_button() - disables given GPIO button
 * @bdata: button data for button to be disabled
 *
 * Disables button pointed by @bdata. This is done by masking
 * IRQ line. After this function is called, button won't generate
 * input events anymore. Note that one can only disable buttons
 * that don't share IRQs.
 *
 * Make sure that @bdata->disable_lock is locked when entering
 * this function to avoid races when concurrent threads are
 * disabling buttons at the same time.
 */
static void gpio_keys_disable_button(struct gpio_button_data *bdata)
{
	if (!bdata->disabled) {
		/*
		 * Disable IRQ and associated timer/work structure.
		 */
		disable_irq(bdata->irq);

		if (bdata->gpiod)
			cancel_delayed_work_sync(&bdata->work);
		else
			del_timer_sync(&bdata->release_timer);

		bdata->disabled = true;
	}
}

/**
 * gpio_keys_enable_button() - enables given GPIO button
 * @bdata: button data for button to be disabled
 *
 * Enables given button pointed by @bdata.
 *
 * Make sure that @bdata->disable_lock is locked when entering
 * this function to avoid races with concurrent threads trying
 * to enable the same button at the same time.
 */
static void gpio_keys_enable_button(struct gpio_button_data *bdata)
{
	if (bdata->disabled) {
		enable_irq(bdata->irq);
		bdata->disabled = false;
	}
}

/**
 * gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
 * @ddata: pointer to drvdata
 * @buf: buffer where stringified bitmap is written
 * @type: button type (%EV_KEY, %EV_SW)
 * @only_disabled: does caller want only those buttons that are
 *                 currently disabled or all buttons that can be
 *                 disabled
 *
 * This function writes buttons that can be disabled to @buf. If
 * @only_disabled is true, then @buf contains only those buttons
 * that are currently disabled. Returns 0 on success or negative
 * errno on failure.
 */
static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
					  char *buf, unsigned int type,
					  bool only_disabled)
{
	int n_events = get_n_events_by_type(type);
	unsigned long *bits;
	ssize_t ret;
	int i;

	bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
	if (!bits)
		return -ENOMEM;

	for (i = 0; i < ddata->pdata->nbuttons; i++) {
		struct gpio_button_data *bdata = &ddata->data[i];

		if (bdata->button->type != type)
			continue;

		if (only_disabled && !bdata->disabled)
			continue;

		__set_bit(*bdata->code, bits);
	}

	ret = scnprintf(buf, PAGE_SIZE - 1, "%*pbl", n_events, bits);
	buf[ret++] = '\n';
	buf[ret] = '\0';

	kfree(bits);

	return ret;
}

/**
 * gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
 * @ddata: pointer to drvdata
 * @buf: buffer from userspace that contains stringified bitmap
 * @type: button type (%EV_KEY, %EV_SW)
 *
 * This function parses stringified bitmap from @buf and disables/enables
 * GPIO buttons accordingly. Returns 0 on success and negative error
 * on failure.
 */
static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
					   const char *buf, unsigned int type)
{
	int n_events = get_n_events_by_type(type);
	const unsigned long *bitmap = get_bm_events_by_type(ddata->input, type);
	unsigned long *bits;
	ssize_t error;
	int i;

	bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
	if (!bits)
		return -ENOMEM;

	error = bitmap_parselist(buf, bits, n_events);
	if (error)
		goto out;

	/* First validate */
	if (!bitmap_subset(bits, bitmap, n_events)) {
		error = -EINVAL;
		goto out;
	}

	for (i = 0; i < ddata->pdata->nbuttons; i++) {
		struct gpio_button_data *bdata = &ddata->data[i];

		if (bdata->button->type != type)
			continue;

		if (test_bit(*bdata->code, bits) &&
		    !bdata->button->can_disable) {
			error = -EINVAL;
			goto out;
		}
	}

	mutex_lock(&ddata->disable_lock);

	for (i = 0; i < ddata->pdata->nbuttons; i++) {
		struct gpio_button_data *bdata = &ddata->data[i];

		if (bdata->button->type != type)
			continue;

		if (test_bit(*bdata->code, bits))
			gpio_keys_disable_button(bdata);
		else
			gpio_keys_enable_button(bdata);
	}

	mutex_unlock(&ddata->disable_lock);

out:
	kfree(bits);
	return error;
}

#define ATTR_SHOW_FN(name, type, only_disabled)				\
static ssize_t gpio_keys_show_##name(struct device *dev,		\
				     struct device_attribute *attr,	\
				     char *buf)				\
{									\
	struct platform_device *pdev = to_platform_device(dev);		\
	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);	\
									\
	return gpio_keys_attr_show_helper(ddata, buf,			\
					  type, only_disabled);		\
}

ATTR_SHOW_FN(keys, EV_KEY, false);
ATTR_SHOW_FN(switches, EV_SW, false);
ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
ATTR_SHOW_FN(disabled_switches, EV_SW, true);

/*
 * ATTRIBUTES:
 *
 * /sys/devices/platform/gpio-keys/keys [ro]
 * /sys/devices/platform/gpio-keys/switches [ro]
 */
static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);

#define ATTR_STORE_FN(name, type)					\
static ssize_t gpio_keys_store_##name(struct device *dev,		\
				      struct device_attribute *attr,	\
				      const char *buf,			\
				      size_t count)			\
{									\
	struct platform_device *pdev = to_platform_device(dev);		\
	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);	\
	ssize_t error;							\
									\
	error = gpio_keys_attr_store_helper(ddata, buf, type);		\
	if (error)							\
		return error;						\
									\
	return count;							\
}

ATTR_STORE_FN(disabled_keys, EV_KEY);
ATTR_STORE_FN(disabled_switches, EV_SW);

/*
 * ATTRIBUTES:
 *
 * /sys/devices/platform/gpio-keys/disabled_keys [rw]
 * /sys/devices/platform/gpio-keys/disables_switches [rw]
 */


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