Re: [PATCH] drivers: misc: add gpio wakeup driver

[Daniel Mack <zonque@gmail.com>]

Hi Fabio,

On 01.10.2013 16:01, Fabio Estevam wrote:
> On Tue, Oct 1, 2013 at 10:55 AM, Daniel Mack <zonque@gmail.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@gmail.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@gmail.com>");
>> +MODULE_DESCRIPTION("Driver to wake up systems from GPIOs");
>> +MODULE_ALIAS("platform:gpio-wakeup");
>> --
>> 1.8.3.1
>>
>> --
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