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Date: Tue, 01 Oct 2013 16:05:07 +0200
From: Daniel Mack <zonque@...il.com>
To: Fabio Estevam <festevam@...il.com>
CC: linux-gpio@...r.kernel.org,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Mark Brown <broonie@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] drivers: misc: add gpio wakeup driver
Hi Fabio,
On 01.10.2013 16:01, Fabio Estevam wrote:
> On Tue, Oct 1, 2013 at 10:55 AM, Daniel Mack <zonque@...il.com> wrote:
>> This patch adds a very simple driver that enables GPIO lines as wakeup
>> sources. It only operates on information passed in via DT, and depends
>
> Isn't it the same as the existing 'gpio-key,wakeup' ?
Of course, I know the gpio-input driver can provide similar
functionality. My intention was just provide a way to wake up the system
without registering an input device for signals nobody is interested in
eventually.
Don't know if that's reason enough to add a new driver though.
Thanks,
Daniel
>
>> on CONFIG_OF && CONFIG_PM_SLEEP. It can for example be used to connect
>> wake-on-LAN (WOL) signals or other electric wakeup networks.
>>
>> The driver accepts a list of GPIO nodes and claims them along with their
>> interrupt line. During suspend, the interrupts will be enabled and
>> selected as wakeup source. The driver doesn't do anything else with the
>> GPIO lines, and will ignore occured interrupts silently.
>>
>> Signed-off-by: Daniel Mack <zonque@...il.com>
>> ---
>> .../devicetree/bindings/misc/gpio-wakeup.txt | 16 ++
>> drivers/misc/Kconfig | 8 +
>> drivers/misc/Makefile | 1 +
>> drivers/misc/gpio-wakeup.c | 162 +++++++++++++++++++++
>> 4 files changed, 187 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/misc/gpio-wakeup.txt
>> create mode 100644 drivers/misc/gpio-wakeup.c
>>
>> diff --git a/Documentation/devicetree/bindings/misc/gpio-wakeup.txt b/Documentation/devicetree/bindings/misc/gpio-wakeup.txt
>> new file mode 100644
>> index 0000000..6aacd0f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/misc/gpio-wakeup.txt
>> @@ -0,0 +1,16 @@
>> +GPIO WAKEUP DRIVER BINDINGS
>> +
>> +Required:
>> +
>> + compatible: Must be "gpio-wakeup"
>> + gpios: At list of GPIO nodes that are enabled as wakeup
>> + sources.
>> +
>> +
>> +Example:
>> +
>> + wake_up {
>> + compatible = "gpio-wakeup";
>> + gpios = <&gpio0 19 0>;
>> + };
>> +
>> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
>> index 8dacd4c..c089280 100644
>> --- a/drivers/misc/Kconfig
>> +++ b/drivers/misc/Kconfig
>> @@ -528,6 +528,14 @@ config SRAM
>> the genalloc API. It is supposed to be used for small on-chip SRAM
>> areas found on many SoCs.
>>
>> +config GPIO_WAKEUP
>> + tristate "GPIO wakeup driver"
>> + depends on PM_SLEEP && OF
>> + help
>> + Say Y to build a driver that can wake up a system from GPIO
>> + lines. See Documentation/devicetree/bindings/gpio-wakeup.txt
>> + for binding details.
>> +
>> source "drivers/misc/c2port/Kconfig"
>> source "drivers/misc/eeprom/Kconfig"
>> source "drivers/misc/cb710/Kconfig"
>> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
>> index c235d5b..ee4df84 100644
>> --- a/drivers/misc/Makefile
>> +++ b/drivers/misc/Makefile
>> @@ -53,3 +53,4 @@ obj-$(CONFIG_INTEL_MEI) += mei/
>> obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/
>> obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o
>> obj-$(CONFIG_SRAM) += sram.o
>> +obj-$(CONFIG_GPIO_WAKEUP) += gpio-wakeup.o
>> diff --git a/drivers/misc/gpio-wakeup.c b/drivers/misc/gpio-wakeup.c
>> new file mode 100644
>> index 0000000..3c1ef88
>> --- /dev/null
>> +++ b/drivers/misc/gpio-wakeup.c
>> @@ -0,0 +1,162 @@
>> +/*
>> + * Driver to select GPIO lines as wakeup sources from DT.
>> + *
>> + * Copyright 2013 Daniel Mack
>> + *
>> + * 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/interrupt.h>
>> +#include <linux/irq.h>
>> +#include <linux/pm.h>
>> +#include <linux/slab.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/gpio.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/of_gpio.h>
>> +
>> +struct gpio_wakeup_priv {
>> + unsigned int count;
>> + unsigned int irq[0];
>> +};
>> +
>> +static irqreturn_t gpio_wakeup_isr(int irq, void *dev_id)
>> +{
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int gpio_wakeup_probe(struct platform_device *pdev)
>> +{
>> + int ret, count, i;
>> + struct gpio_wakeup_priv *priv;
>> + struct device *dev = &pdev->dev;
>> + struct device_node *np = dev->of_node;
>> +
>> + if (!np)
>> + return -EINVAL;
>> +
>> + count = of_gpio_count(np);
>> + if (count == 0)
>> + return -EINVAL;
>> +
>> + priv = devm_kzalloc(dev, sizeof(*priv) +
>> + sizeof(int) * count, GFP_KERNEL);
>> + if (!priv)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < count; i++) {
>> + unsigned int gpio, irq;
>> +
>> + priv->irq[i] = -EINVAL;
>> +
>> + gpio = of_get_gpio(np, i);
>> + if (gpio < 0) {
>> + dev_warn(dev, "Unable to get gpio #%d\n", i);
>> + continue;
>> + }
>> +
>> + irq = gpio_to_irq(gpio);
>> + if (irq < 0) {
>> + dev_warn(dev, "Can't map GPIO %d to an IRQ\n", gpio);
>> + continue;
>> + }
>> +
>> + ret = devm_gpio_request_one(dev, gpio, GPIOF_IN, pdev->name);
>> + if (ret < 0) {
>> + dev_warn(dev, "Unable to request GPIO %d: %d\n",
>> + gpio, ret);
>> + continue;
>> + }
>> +
>> + ret = devm_request_irq(dev, irq, gpio_wakeup_isr,
>> + IRQF_TRIGGER_RISING |
>> + IRQF_TRIGGER_FALLING,
>> + pdev->name, NULL);
>> + if (ret < 0) {
>> + dev_warn(dev, "Unable to request IRQ %d\n", irq);
>> + continue;
>> + }
>> +
>> + disable_irq(irq);
>> + priv->irq[i] = irq;
>> +
>> + dev_info(dev, "Adding GPIO %d (IRQ %d) to wakeup sources\n",
>> + gpio, irq);
>> + }
>> +
>> + priv->count = count;
>> + device_init_wakeup(dev, 1);
>> + platform_set_drvdata(pdev, priv);
>> +
>> + return 0;
>> +}
>> +
>> +static int gpio_wakeup_suspend(struct device *dev)
>> +{
>> + struct gpio_wakeup_priv *priv = dev_get_drvdata(dev);
>> + int i;
>> +
>> + for (i = 0; i < priv->count; i++)
>> + if (priv->irq[i] >= 0) {
>> + enable_irq(priv->irq[i]);
>> + enable_irq_wake(priv->irq[i]);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int gpio_wakeup_resume(struct device *dev)
>> +{
>> + struct gpio_wakeup_priv *priv = dev_get_drvdata(dev);
>> + int i;
>> +
>> + for (i = 0; i < priv->count; i++)
>> + if (priv->irq[i] >= 0) {
>> + disable_irq_wake(priv->irq[i]);
>> + disable_irq(priv->irq[i]);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static SIMPLE_DEV_PM_OPS(gpio_wakeup_pm_ops,
>> + gpio_wakeup_suspend, gpio_wakeup_resume);
>> +
>> +static struct of_device_id gpio_wakeup_of_match[] = {
>> + { .compatible = "gpio-wakeup", },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, gpio_wakeup_of_match);
>> +
>> +static struct platform_driver gpio_wakeup_driver = {
>> + .probe = gpio_wakeup_probe,
>> + .driver = {
>> + .name = "gpio-wakeup",
>> + .owner = THIS_MODULE,
>> + .pm = &gpio_wakeup_pm_ops,
>> + .of_match_table = of_match_ptr(gpio_wakeup_of_match),
>> + }
>> +};
>> +
>> +static int __init gpio_wakeup_init(void)
>> +{
>> + return platform_driver_register(&gpio_wakeup_driver);
>> +}
>> +
>> +static void __exit gpio_wakeup_exit(void)
>> +{
>> + platform_driver_unregister(&gpio_wakeup_driver);
>> +}
>> +
>> +late_initcall(gpio_wakeup_init);
>> +module_exit(gpio_wakeup_exit);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_AUTHOR("Daniel Mack <zonque@...il.com>");
>> +MODULE_DESCRIPTION("Driver to wake up systems from GPIOs");
>> +MODULE_ALIAS("platform:gpio-wakeup");
>> --
>> 1.8.3.1
>>
>> --
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