From patchwork Sun Jan 6 10:10:35 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Lunn X-Patchwork-Id: 1937421 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id DC9723FED4 for ; Sun, 6 Jan 2013 10:15:09 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TrnCR-0006Kq-6S; Sun, 06 Jan 2013 10:11:27 +0000 Received: from londo.lunn.ch ([80.238.139.98]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TrnC7-0006In-S8 for linux-arm-kernel@lists.infradead.org; Sun, 06 Jan 2013 10:11:13 +0000 Received: from lunn by londo.lunn.ch with local (Exim 3.36 #1 (Debian)) id 1TrnC1-0001IF-00; Sun, 06 Jan 2013 11:11:01 +0100 From: Andrew Lunn To: linux ARM Subject: [PATCH 02/11] Power: gpio-poweroff: Fix documentation and gpio_is_valid Date: Sun, 6 Jan 2013 11:10:35 +0100 Message-Id: <1357467044-4914-3-git-send-email-andrew@lunn.ch> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1357467044-4914-1-git-send-email-andrew@lunn.ch> References: <1357467044-4914-1-git-send-email-andrew@lunn.ch> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130106_051108_560770_6A3FE7C5 X-CRM114-Status: GOOD ( 18.10 ) X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Thomas Petazzoni , Andrew Lunn , mturquette@linaro.org, Jason Cooper , Arnd Bergmann , swarren@wwwdotorg.org, Olof Johansson X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Improve the documentation to clarify level vs edge triggered power off. Improve the comments for level vs edge triggered power off. Make use of gpio_is_valid(). Reported-by: Stephen Warren Signed-off-by: Andrew Lunn --- .../devicetree/bindings/gpio/gpio-poweroff.txt | 20 ++++++++++-- drivers/power/reset/gpio-poweroff.c | 33 +++++++++----------- 2 files changed, 32 insertions(+), 21 deletions(-) diff --git a/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt b/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt index 558cdf3..d4eab92 100644 --- a/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt +++ b/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt @@ -1,4 +1,19 @@ -GPIO line that should be set high/low to power off a device +Driver a GPIO line that can be used to turn the power off. + +The driver supports both level triggered and edge triggered power off. +At driver load time, the driver will request the given gpio line and +install a pm_power_off handler. If the optional properties 'input' is +not found, the GPIO line will be driven in the inactive +state. Otherwise its configured as an input. + +When the pm_power_off is called, the gpio is configured as an output, +and drive active, so triggering a level triggered power off +condition. This will also cause an inactive->active edge condition, so +triggering positive edge triggered power off. After a delay of 100ms, +the GPIO is set to inactive, thus causing an active->inactive edge, +triggering negative edge triggered power off. After another 100ms +delay the GPIO is driver active again. If the power is still on and +the CPU still running after a 3000ms delay, a WARN_ON(1) is emitted. Required properties: - compatible : should be "gpio-poweroff". @@ -13,10 +28,9 @@ Optional properties: property is not specified, the GPIO is initialized as an output in its inactive state. - Examples: gpio-poweroff { compatible = "gpio-poweroff"; - gpios = <&gpio 4 0>; /* GPIO 4 Active Low */ + gpios = <&gpio 4 0>; }; diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c index 0491e53..adc943b 100644 --- a/drivers/power/reset/gpio-poweroff.c +++ b/drivers/power/reset/gpio-poweroff.c @@ -29,15 +29,16 @@ static int gpio_active_low; static void gpio_poweroff_do_poweroff(void) { - BUG_ON(gpio_num == -1); + BUG_ON(!gpio_is_valid(gpio_num)); - /* drive it active */ + /* drive it active, also inactive->active edge */ gpio_direction_output(gpio_num, !gpio_active_low); mdelay(100); - /* rising edge or drive inactive */ + /* drive inactive, also active->inactive edge */ gpio_set_value(gpio_num, gpio_active_low); mdelay(100); - /* falling edge */ + + /* drive it active, also inactive->active edge */ gpio_set_value(gpio_num, !gpio_active_low); /* give it some time */ @@ -60,15 +61,12 @@ static int __devinit gpio_poweroff_probe(struct platform_device *pdev) } gpio_num = of_get_gpio_flags(pdev->dev.of_node, 0, &flags); - if (gpio_num < 0) { - pr_err("%s: Could not get GPIO configuration: %d", - __func__, gpio_num); - return -ENODEV; - } + if (!gpio_is_valid(gpio_num)) + return gpio_num; + gpio_active_low = flags & OF_GPIO_ACTIVE_LOW; - if (of_get_property(pdev->dev.of_node, "input", NULL)) - input = true; + input = of_property_read_bool(pdev->dev.of_node, "input"); ret = gpio_request(gpio_num, "poweroff-gpio"); if (ret) { @@ -98,8 +96,7 @@ err: static int __devexit gpio_poweroff_remove(struct platform_device *pdev) { - if (gpio_num != -1) - gpio_free(gpio_num); + gpio_free(gpio_num); if (pm_power_off == &gpio_poweroff_do_poweroff) pm_power_off = NULL; @@ -115,15 +112,15 @@ static struct platform_driver gpio_poweroff_driver = { .probe = gpio_poweroff_probe, .remove = __devexit_p(gpio_poweroff_remove), .driver = { - .name = "poweroff-gpio", - .owner = THIS_MODULE, - .of_match_table = of_gpio_poweroff_match, - }, + .name = "poweroff-gpio", + .owner = THIS_MODULE, + .of_match_table = of_gpio_poweroff_match, + }, }; module_platform_driver(gpio_poweroff_driver); MODULE_AUTHOR("Jamie Lentin "); MODULE_DESCRIPTION("GPIO poweroff driver"); -MODULE_LICENSE("GPL"); +MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:poweroff-gpio");