From patchwork Fri Nov 20 08:40:55 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Torokhov X-Patchwork-Id: 61612 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id nAK8fG0g023583 for ; Fri, 20 Nov 2009 08:41:16 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750715AbZKTIkz (ORCPT ); Fri, 20 Nov 2009 03:40:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751661AbZKTIkz (ORCPT ); Fri, 20 Nov 2009 03:40:55 -0500 Received: from mail-pz0-f171.google.com ([209.85.222.171]:55502 "EHLO mail-pz0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750715AbZKTIky (ORCPT ); Fri, 20 Nov 2009 03:40:54 -0500 Received: by pzk1 with SMTP id 1so2260613pzk.33 for ; Fri, 20 Nov 2009 00:41:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:date:from:to:cc:subject :message-id:references:mime-version:content-type:content-disposition :in-reply-to:user-agent; bh=MGJf9At2D3vTfkMXvfFdDjXF+l1TiN4ySdcQmNo8tM8=; b=lPvO5XUUlrCH4PmBeXjJvjFubZSNUIRsWOv6nkywGQ/pR3QAuybe9XmScaMX5ObQi2 pmKFXZkOgxXcbjSIddLI1hzQDxhwOBStXIpW6S3N1RH7U7uiLMUHXU43yhEBBsxci7aG XEYR+oOfKw7SqsM4D/jWOMZ+sdTh1oYSMhIV0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=RvilkUocNNcASNFioUMZ6JZbXQMfvgPyx8XlfKYklJEpWJQKFhKpkWMlmYk3PqFMgu PErDaYlwCJnEu4LRKmsgBHo5629upLkoqa7f3Eu8BtbNjLTDVgPKhgEddxxg+lkucKQW peohdK4oLdOsGMdE+N57J9+12FcLTU5qe74DI= Received: by 10.114.236.28 with SMTP id j28mr1681804wah.162.1258706460070; Fri, 20 Nov 2009 00:41:00 -0800 (PST) Received: from mailhub.coreip.homeip.net (c-24-6-153-137.hsd1.ca.comcast.net [24.6.153.137]) by mx.google.com with ESMTPS id 22sm816032pzk.14.2009.11.20.00.40.57 (version=TLSv1/SSLv3 cipher=RC4-MD5); Fri, 20 Nov 2009 00:40:58 -0800 (PST) Date: Fri, 20 Nov 2009 00:40:55 -0800 From: Dmitry Torokhov To: Mika Westerberg Cc: linux-input@vger.kernel.org Subject: Re: [PATCH 2/2] Input: gpio-keys: added support for disabling gpios through sysfs Message-ID: <20091120084054.GC3009@core.coreip.homeip.net> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c index 113d187..3e534db 100644 --- a/drivers/input/keyboard/gpio_keys.c +++ b/drivers/input/keyboard/gpio_keys.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -30,13 +31,299 @@ struct gpio_button_data { struct input_dev *input; struct timer_list timer; struct work_struct work; + bool can_disable; + bool disabled; }; struct gpio_keys_drvdata { struct input_dev *input; + struct mutex disable_lock; + unsigned int n_buttons; 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. + * + * Note that we allow user to specify other bits that are allowed (as + * long as she doesn't try to use bits higher than KEY_CNT or SW_CNT). + * User can disable bunch of keys for example like this: + * echo 0-600 > disabled_keys + * and we only disable those keys that can be disabled. + * + * We can disable only those keys who have specified 'exclusive_irq = 1' + * in their platform data (e.g shared IRQs cannot be disabled). + */ + +/** + * 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 inline int get_n_events_by_type(int type) +{ + BUG_ON(type != EV_SW && type != EV_KEY); + + return (type == EV_KEY) ? KEY_CNT : SW_CNT; +} + +/** + * 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) +{ + BUG_ON(bdata->button->exclusive_irq == 0); + + if (!bdata->disabled) { + /* + * Disable IRQ and possible debouncing timer. + */ + disable_irq(gpio_to_irq(bdata->button->gpio)); + if (bdata->button->debounce_interval) + del_timer_sync(&bdata->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(gpio_to_irq(bdata->button->gpio)); + 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->n_buttons; i++) { + struct gpio_button_data *bdata = &ddata->data[i]; + + if (bdata->button->type != type) + continue; + + if (only_disabled && !bdata->disabled) + continue; + + __set_bit(bdata->button->code, bits); + } + + ret = bitmap_scnlistprintf(buf, PAGE_SIZE - 2, bits, n_events); + 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 accordinly. 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); + 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 */ + for (i = 0; i < ddata->n_buttons; i++) { + struct gpio_button_data *bdata = &ddata->data[i]; + + if (bdata->button->type != type) + continue; + + if (test_bit(bdata->button->code, bits) && + !bdata->can_disable) { + error = -EINVAL; + goto out; + } + } + + mutex_lock(&ddata->disable_lock); + + for (i = 0; i < ddata->n_buttons; i++) { + struct gpio_button_data *bdata = &ddata->data[i]; + + if (bdata->button->type != type) + continue; + + if (test_bit(bdata->button->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] + */ +static DEVICE_ATTR(disabled_keys, S_IWUSR | S_IRUGO, + gpio_keys_show_disabled_keys, + gpio_keys_store_disabled_keys); +static DEVICE_ATTR(disabled_switches, S_IWUSR | S_IRUGO, + gpio_keys_show_disabled_switches, + gpio_keys_store_disabled_switches); + +static struct attribute *gpio_keys_attrs[] = { + &dev_attr_keys.attr, + &dev_attr_switches.attr, + &dev_attr_disabled_keys.attr, + &dev_attr_disabled_switches.attr, + NULL, +}; + +static struct attribute_group gpio_keys_attr_group = { + .attrs = gpio_keys_attrs, +}; + static void gpio_keys_report_event(struct work_struct *work) { struct gpio_button_data *bdata = @@ -73,11 +360,12 @@ static irqreturn_t gpio_keys_isr(int irq, void *dev_id) return IRQ_HANDLED; } -static int __devinit gpio_keys_setup_key(struct device *dev, +static int __devinit gpio_keys_setup_key(struct platform_device *pdev, struct gpio_button_data *bdata, struct gpio_keys_button *button) { char *desc = button->desc ? button->desc : "gpio_keys"; + struct device *dev = &pdev->dev; unsigned long irqflags; int irq, error; @@ -114,6 +402,8 @@ static int __devinit gpio_keys_setup_key(struct device *dev, */ if (!button->exclusive_irq) irqflags |= IRQF_SHARED; + else + bdata->can_disable = true; error = request_irq(irq, gpio_keys_isr, irqflags, desc, bdata); if (error) { @@ -149,6 +439,10 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev) goto fail1; } + ddata->input = input; + ddata->n_buttons = pdata->nbuttons; + mutex_init(&ddata->disable_lock); + platform_set_drvdata(pdev, ddata); input->name = pdev->name; @@ -164,8 +458,6 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev) if (pdata->rep) __set_bit(EV_REP, input->evbit); - ddata->input = input; - for (i = 0; i < pdata->nbuttons; i++) { struct gpio_keys_button *button = &pdata->buttons[i]; struct gpio_button_data *bdata = &ddata->data[i]; @@ -174,7 +466,7 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev) bdata->input = input; bdata->button = button; - error = gpio_keys_setup_key(dev, bdata, button); + error = gpio_keys_setup_key(pdev, bdata, button); if (error) goto fail2; @@ -184,17 +476,26 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev) input_set_capability(input, type, button->code); } - error = input_register_device(input); + error = sysfs_create_group(&pdev->dev.kobj, &gpio_keys_attr_group); if (error) { - dev_err(dev, "Unable to register input device, " - "error: %d\n", error); + dev_err(dev, "Unable to export keys/switches, error: %d\n", + error); goto fail2; } + error = input_register_device(input); + if (error) { + dev_err(dev, "Unable to register input device, error: %d\n", + error); + goto fail3; + } + device_init_wakeup(&pdev->dev, wakeup); return 0; + fail3: + sysfs_remove_group(&pdev->dev.kobj, &gpio_keys_attr_group); fail2: while (--i >= 0) { free_irq(gpio_to_irq(pdata->buttons[i].gpio), &ddata->data[i]); @@ -219,10 +520,13 @@ static int __devexit gpio_keys_remove(struct platform_device *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 (pdata->buttons[i].debounce_interval) del_timer_sync(&ddata->data[i].timer);