![Grazvydas Ignotas](/assets/img/avatar_default.png)
gpiolib now has debounce support added in .35, so let's make use of it. This allows to use hardware GPIO debouncing on some platforms like OMAP. In case gpiolib debounce setup fails for some GPIO, the driver will fall back to timer based debouncing, which is what it used before. Signed-off-by: Grazvydas Ignotas <notasas@gmail.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
627 lines
16 KiB
C
627 lines
16 KiB
C
/*
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* Driver for keys on GPIO lines capable of generating interrupts.
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*
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* Copyright 2005 Phil Blundell
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/sched.h>
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#include <linux/pm.h>
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#include <linux/slab.h>
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#include <linux/sysctl.h>
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#include <linux/proc_fs.h>
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <linux/input.h>
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#include <linux/gpio_keys.h>
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#include <linux/workqueue.h>
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#include <linux/gpio.h>
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struct gpio_button_data {
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struct gpio_keys_button *button;
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struct input_dev *input;
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struct timer_list timer;
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struct work_struct work;
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int timer_debounce; /* in msecs */
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bool disabled;
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};
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struct gpio_keys_drvdata {
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struct input_dev *input;
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struct mutex disable_lock;
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unsigned int n_buttons;
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struct gpio_button_data data[0];
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};
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/*
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* SYSFS interface for enabling/disabling keys and switches:
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*
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* There are 4 attributes under /sys/devices/platform/gpio-keys/
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* keys [ro] - bitmap of keys (EV_KEY) which can be
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* disabled
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* switches [ro] - bitmap of switches (EV_SW) which can be
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* disabled
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* disabled_keys [rw] - bitmap of keys currently disabled
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* disabled_switches [rw] - bitmap of switches currently disabled
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*
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* Userland can change these values and hence disable event generation
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* for each key (or switch). Disabling a key means its interrupt line
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* is disabled.
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*
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* For example, if we have following switches set up as gpio-keys:
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* SW_DOCK = 5
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* SW_CAMERA_LENS_COVER = 9
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* SW_KEYPAD_SLIDE = 10
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* SW_FRONT_PROXIMITY = 11
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* This is read from switches:
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* 11-9,5
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* Next we want to disable proximity (11) and dock (5), we write:
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* 11,5
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* to file disabled_switches. Now proximity and dock IRQs are disabled.
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* This can be verified by reading the file disabled_switches:
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* 11,5
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* If we now want to enable proximity (11) switch we write:
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* 5
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* to disabled_switches.
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*
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* We can disable only those keys which don't allow sharing the irq.
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*/
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/**
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* get_n_events_by_type() - returns maximum number of events per @type
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* @type: type of button (%EV_KEY, %EV_SW)
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*
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* Return value of this function can be used to allocate bitmap
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* large enough to hold all bits for given type.
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*/
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static inline int get_n_events_by_type(int type)
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{
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BUG_ON(type != EV_SW && type != EV_KEY);
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return (type == EV_KEY) ? KEY_CNT : SW_CNT;
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}
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/**
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* gpio_keys_disable_button() - disables given GPIO button
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* @bdata: button data for button to be disabled
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*
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* Disables button pointed by @bdata. This is done by masking
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* IRQ line. After this function is called, button won't generate
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* input events anymore. Note that one can only disable buttons
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* that don't share IRQs.
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*
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* Make sure that @bdata->disable_lock is locked when entering
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* this function to avoid races when concurrent threads are
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* disabling buttons at the same time.
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*/
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static void gpio_keys_disable_button(struct gpio_button_data *bdata)
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{
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if (!bdata->disabled) {
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/*
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* Disable IRQ and possible debouncing timer.
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*/
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disable_irq(gpio_to_irq(bdata->button->gpio));
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if (bdata->timer_debounce)
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del_timer_sync(&bdata->timer);
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bdata->disabled = true;
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}
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}
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/**
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* gpio_keys_enable_button() - enables given GPIO button
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* @bdata: button data for button to be disabled
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*
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* Enables given button pointed by @bdata.
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*
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* Make sure that @bdata->disable_lock is locked when entering
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* this function to avoid races with concurrent threads trying
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* to enable the same button at the same time.
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*/
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static void gpio_keys_enable_button(struct gpio_button_data *bdata)
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{
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if (bdata->disabled) {
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enable_irq(gpio_to_irq(bdata->button->gpio));
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bdata->disabled = false;
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}
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}
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/**
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* gpio_keys_attr_show_helper() - fill in stringified bitmap of buttons
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* @ddata: pointer to drvdata
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* @buf: buffer where stringified bitmap is written
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* @type: button type (%EV_KEY, %EV_SW)
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* @only_disabled: does caller want only those buttons that are
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* currently disabled or all buttons that can be
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* disabled
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*
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* This function writes buttons that can be disabled to @buf. If
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* @only_disabled is true, then @buf contains only those buttons
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* that are currently disabled. Returns 0 on success or negative
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* errno on failure.
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*/
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static ssize_t gpio_keys_attr_show_helper(struct gpio_keys_drvdata *ddata,
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char *buf, unsigned int type,
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bool only_disabled)
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{
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int n_events = get_n_events_by_type(type);
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unsigned long *bits;
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ssize_t ret;
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int i;
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bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
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if (!bits)
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return -ENOMEM;
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for (i = 0; i < ddata->n_buttons; i++) {
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struct gpio_button_data *bdata = &ddata->data[i];
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if (bdata->button->type != type)
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continue;
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if (only_disabled && !bdata->disabled)
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continue;
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__set_bit(bdata->button->code, bits);
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}
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ret = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events);
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buf[ret++] = '\n';
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buf[ret] = '\0';
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kfree(bits);
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return ret;
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}
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/**
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* gpio_keys_attr_store_helper() - enable/disable buttons based on given bitmap
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* @ddata: pointer to drvdata
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* @buf: buffer from userspace that contains stringified bitmap
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* @type: button type (%EV_KEY, %EV_SW)
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*
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* This function parses stringified bitmap from @buf and disables/enables
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* GPIO buttons accordinly. Returns 0 on success and negative error
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* on failure.
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*/
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static ssize_t gpio_keys_attr_store_helper(struct gpio_keys_drvdata *ddata,
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const char *buf, unsigned int type)
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{
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int n_events = get_n_events_by_type(type);
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unsigned long *bits;
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ssize_t error;
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int i;
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bits = kcalloc(BITS_TO_LONGS(n_events), sizeof(*bits), GFP_KERNEL);
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if (!bits)
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return -ENOMEM;
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error = bitmap_parselist(buf, bits, n_events);
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if (error)
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goto out;
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/* First validate */
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for (i = 0; i < ddata->n_buttons; i++) {
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struct gpio_button_data *bdata = &ddata->data[i];
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if (bdata->button->type != type)
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continue;
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if (test_bit(bdata->button->code, bits) &&
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!bdata->button->can_disable) {
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error = -EINVAL;
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goto out;
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}
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}
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mutex_lock(&ddata->disable_lock);
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for (i = 0; i < ddata->n_buttons; i++) {
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struct gpio_button_data *bdata = &ddata->data[i];
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if (bdata->button->type != type)
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continue;
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if (test_bit(bdata->button->code, bits))
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gpio_keys_disable_button(bdata);
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else
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gpio_keys_enable_button(bdata);
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}
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mutex_unlock(&ddata->disable_lock);
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out:
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kfree(bits);
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return error;
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}
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#define ATTR_SHOW_FN(name, type, only_disabled) \
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static ssize_t gpio_keys_show_##name(struct device *dev, \
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struct device_attribute *attr, \
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char *buf) \
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{ \
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struct platform_device *pdev = to_platform_device(dev); \
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struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
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\
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return gpio_keys_attr_show_helper(ddata, buf, \
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type, only_disabled); \
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}
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ATTR_SHOW_FN(keys, EV_KEY, false);
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ATTR_SHOW_FN(switches, EV_SW, false);
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ATTR_SHOW_FN(disabled_keys, EV_KEY, true);
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ATTR_SHOW_FN(disabled_switches, EV_SW, true);
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/*
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* ATTRIBUTES:
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*
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* /sys/devices/platform/gpio-keys/keys [ro]
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* /sys/devices/platform/gpio-keys/switches [ro]
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*/
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static DEVICE_ATTR(keys, S_IRUGO, gpio_keys_show_keys, NULL);
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static DEVICE_ATTR(switches, S_IRUGO, gpio_keys_show_switches, NULL);
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#define ATTR_STORE_FN(name, type) \
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static ssize_t gpio_keys_store_##name(struct device *dev, \
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struct device_attribute *attr, \
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const char *buf, \
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size_t count) \
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{ \
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struct platform_device *pdev = to_platform_device(dev); \
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struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev); \
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ssize_t error; \
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\
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error = gpio_keys_attr_store_helper(ddata, buf, type); \
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if (error) \
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return error; \
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\
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return count; \
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}
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ATTR_STORE_FN(disabled_keys, EV_KEY);
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ATTR_STORE_FN(disabled_switches, EV_SW);
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/*
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* ATTRIBUTES:
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*
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* /sys/devices/platform/gpio-keys/disabled_keys [rw]
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* /sys/devices/platform/gpio-keys/disables_switches [rw]
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*/
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static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO,
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gpio_keys_show_disabled_keys,
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gpio_keys_store_disabled_keys);
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static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO,
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gpio_keys_show_disabled_switches,
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gpio_keys_store_disabled_switches);
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static struct attribute *gpio_keys_attrs[] = {
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&dev_attr_keys.attr,
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&dev_attr_switches.attr,
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&dev_attr_disabled_keys.attr,
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&dev_attr_disabled_switches.attr,
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NULL,
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};
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static struct attribute_group gpio_keys_attr_group = {
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.attrs = gpio_keys_attrs,
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};
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static void gpio_keys_report_event(struct gpio_button_data *bdata)
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{
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struct gpio_keys_button *button = bdata->button;
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struct input_dev *input = bdata->input;
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unsigned int type = button->type ?: EV_KEY;
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int state = (gpio_get_value(button->gpio) ? 1 : 0) ^ button->active_low;
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input_event(input, type, button->code, !!state);
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input_sync(input);
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}
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static void gpio_keys_work_func(struct work_struct *work)
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{
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struct gpio_button_data *bdata =
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container_of(work, struct gpio_button_data, work);
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gpio_keys_report_event(bdata);
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}
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static void gpio_keys_timer(unsigned long _data)
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{
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struct gpio_button_data *data = (struct gpio_button_data *)_data;
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schedule_work(&data->work);
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}
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static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
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{
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struct gpio_button_data *bdata = dev_id;
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struct gpio_keys_button *button = bdata->button;
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BUG_ON(irq != gpio_to_irq(button->gpio));
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if (bdata->timer_debounce)
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mod_timer(&bdata->timer,
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jiffies + msecs_to_jiffies(bdata->timer_debounce));
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else
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schedule_work(&bdata->work);
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return IRQ_HANDLED;
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}
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static int __devinit gpio_keys_setup_key(struct platform_device *pdev,
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struct gpio_button_data *bdata,
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struct gpio_keys_button *button)
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{
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char *desc = button->desc ? button->desc : "gpio_keys";
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struct device *dev = &pdev->dev;
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unsigned long irqflags;
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int irq, error;
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setup_timer(&bdata->timer, gpio_keys_timer, (unsigned long)bdata);
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INIT_WORK(&bdata->work, gpio_keys_work_func);
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error = gpio_request(button->gpio, desc);
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if (error < 0) {
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dev_err(dev, "failed to request GPIO %d, error %d\n",
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button->gpio, error);
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goto fail2;
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}
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error = gpio_direction_input(button->gpio);
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if (error < 0) {
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dev_err(dev, "failed to configure"
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" direction for GPIO %d, error %d\n",
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button->gpio, error);
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goto fail3;
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}
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if (button->debounce_interval) {
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error = gpio_set_debounce(button->gpio,
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button->debounce_interval * 1000);
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/* use timer if gpiolib doesn't provide debounce */
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if (error < 0)
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bdata->timer_debounce = button->debounce_interval;
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}
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irq = gpio_to_irq(button->gpio);
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if (irq < 0) {
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error = irq;
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dev_err(dev, "Unable to get irq number for GPIO %d, error %d\n",
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button->gpio, error);
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goto fail3;
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}
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irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
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/*
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* If platform has specified that the button can be disabled,
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* we don't want it to share the interrupt line.
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*/
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if (!button->can_disable)
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irqflags |= IRQF_SHARED;
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error = request_irq(irq, gpio_keys_isr, irqflags, desc, bdata);
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if (error) {
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dev_err(dev, "Unable to claim irq %d; error %d\n",
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irq, error);
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goto fail3;
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}
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return 0;
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fail3:
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gpio_free(button->gpio);
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fail2:
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return error;
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}
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static int __devinit gpio_keys_probe(struct platform_device *pdev)
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{
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struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
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struct gpio_keys_drvdata *ddata;
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struct device *dev = &pdev->dev;
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struct input_dev *input;
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int i, error;
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int wakeup = 0;
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ddata = kzalloc(sizeof(struct gpio_keys_drvdata) +
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pdata->nbuttons * sizeof(struct gpio_button_data),
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GFP_KERNEL);
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input = input_allocate_device();
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if (!ddata || !input) {
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dev_err(dev, "failed to allocate state\n");
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error = -ENOMEM;
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goto fail1;
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}
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ddata->input = input;
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ddata->n_buttons = pdata->nbuttons;
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mutex_init(&ddata->disable_lock);
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platform_set_drvdata(pdev, ddata);
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input->name = pdev->name;
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input->phys = "gpio-keys/input0";
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input->dev.parent = &pdev->dev;
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input->id.bustype = BUS_HOST;
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input->id.vendor = 0x0001;
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input->id.product = 0x0001;
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input->id.version = 0x0100;
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/* Enable auto repeat feature of Linux input subsystem */
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if (pdata->rep)
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__set_bit(EV_REP, input->evbit);
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for (i = 0; i < pdata->nbuttons; i++) {
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struct gpio_keys_button *button = &pdata->buttons[i];
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struct gpio_button_data *bdata = &ddata->data[i];
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unsigned int type = button->type ?: EV_KEY;
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bdata->input = input;
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bdata->button = button;
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error = gpio_keys_setup_key(pdev, bdata, button);
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if (error)
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goto fail2;
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if (button->wakeup)
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wakeup = 1;
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input_set_capability(input, type, button->code);
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}
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error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group);
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if (error) {
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dev_err(dev, "Unable to export keys/switches, error: %d\n",
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error);
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goto fail2;
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}
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error = input_register_device(input);
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if (error) {
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dev_err(dev, "Unable to register input device, error: %d\n",
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error);
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goto fail3;
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}
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/* get current state of buttons */
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for (i = 0; i < pdata->nbuttons; i++)
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gpio_keys_report_event(&ddata->data[i]);
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input_sync(input);
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device_init_wakeup(&pdev->dev, wakeup);
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return 0;
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fail3:
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sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
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fail2:
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while (--i >= 0) {
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free_irq(gpio_to_irq(pdata->buttons[i].gpio), &ddata->data[i]);
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if (ddata->data[i].timer_debounce)
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del_timer_sync(&ddata->data[i].timer);
|
|
cancel_work_sync(&ddata->data[i].work);
|
|
gpio_free(pdata->buttons[i].gpio);
|
|
}
|
|
|
|
platform_set_drvdata(pdev, NULL);
|
|
fail1:
|
|
input_free_device(input);
|
|
kfree(ddata);
|
|
|
|
return error;
|
|
}
|
|
|
|
static int __devexit gpio_keys_remove(struct platform_device *pdev)
|
|
{
|
|
struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
|
|
struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
|
|
struct input_dev *input = ddata->input;
|
|
int i;
|
|
|
|
sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group);
|
|
|
|
device_init_wakeup(&pdev->dev, 0);
|
|
|
|
for (i = 0; i < pdata->nbuttons; i++) {
|
|
int irq = gpio_to_irq(pdata->buttons[i].gpio);
|
|
free_irq(irq, &ddata->data[i]);
|
|
if (ddata->data[i].timer_debounce)
|
|
del_timer_sync(&ddata->data[i].timer);
|
|
cancel_work_sync(&ddata->data[i].work);
|
|
gpio_free(pdata->buttons[i].gpio);
|
|
}
|
|
|
|
input_unregister_device(input);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
#ifdef CONFIG_PM
|
|
static int gpio_keys_suspend(struct device *dev)
|
|
{
|
|
struct platform_device *pdev = to_platform_device(dev);
|
|
struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
|
|
int i;
|
|
|
|
if (device_may_wakeup(&pdev->dev)) {
|
|
for (i = 0; i < pdata->nbuttons; i++) {
|
|
struct gpio_keys_button *button = &pdata->buttons[i];
|
|
if (button->wakeup) {
|
|
int irq = gpio_to_irq(button->gpio);
|
|
enable_irq_wake(irq);
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gpio_keys_resume(struct device *dev)
|
|
{
|
|
struct platform_device *pdev = to_platform_device(dev);
|
|
struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
|
|
struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
|
|
int i;
|
|
|
|
for (i = 0; i < pdata->nbuttons; i++) {
|
|
|
|
struct gpio_keys_button *button = &pdata->buttons[i];
|
|
if (button->wakeup && device_may_wakeup(&pdev->dev)) {
|
|
int irq = gpio_to_irq(button->gpio);
|
|
disable_irq_wake(irq);
|
|
}
|
|
|
|
gpio_keys_report_event(&ddata->data[i]);
|
|
}
|
|
input_sync(ddata->input);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct dev_pm_ops gpio_keys_pm_ops = {
|
|
.suspend = gpio_keys_suspend,
|
|
.resume = gpio_keys_resume,
|
|
};
|
|
#endif
|
|
|
|
static struct platform_driver gpio_keys_device_driver = {
|
|
.probe = gpio_keys_probe,
|
|
.remove = __devexit_p(gpio_keys_remove),
|
|
.driver = {
|
|
.name = "gpio-keys",
|
|
.owner = THIS_MODULE,
|
|
#ifdef CONFIG_PM
|
|
.pm = &gpio_keys_pm_ops,
|
|
#endif
|
|
}
|
|
};
|
|
|
|
static int __init gpio_keys_init(void)
|
|
{
|
|
return platform_driver_register(&gpio_keys_device_driver);
|
|
}
|
|
|
|
static void __exit gpio_keys_exit(void)
|
|
{
|
|
platform_driver_unregister(&gpio_keys_device_driver);
|
|
}
|
|
|
|
module_init(gpio_keys_init);
|
|
module_exit(gpio_keys_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
|
|
MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");
|
|
MODULE_ALIAS("platform:gpio-keys");
|