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Date: Mon, 1 Dec 2014 10:21:40 -0800
From: Sören Brinkmann <soren.brinkmann@...inx.com>
To: Linus Walleij <linus.walleij@...aro.org>,
Alexandre Courbot <gnurou@...il.com>
CC: Jonathan Corbet <corbet@....net>, <linux-kernel@...r.kernel.org>,
<linux-api@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
<linux-doc@...r.kernel.org>
Subject: Re: [PATCH v3] gpio: lib-sysfs: Add 'wakeup' attribute
Another month past. Any updates on this?
Thanks,
Sören
On Mon, 2014-10-27 at 11:30AM -0700, Soren Brinkmann wrote:
> Add an attribute 'wakeup' to the GPIO sysfs interface which allows
> marking/unmarking a GPIO as wake IRQ.
> The file 'wakeup' is created in each exported GPIOs directory, if an IRQ
> is associated with that GPIO and the irqchip implements set_wake().
> Writing 'enabled' to that file will enable wake for that GPIO, while
> writing 'disabled' will disable wake.
> Reading that file will return either 'disabled' or 'enabled' depening on
> the currently set flag for the GPIO's IRQ.
>
> Signed-off-by: Soren Brinkmann <soren.brinkmann@...inx.com>
> Reviewed-by: Alexandre Courbot <acourbot@...dia.com>
> ---
> v3:
> - add documentation
> v2:
> - fix error path to unlock mutex before return
>
> As additional reference, these are the email threads of the v2 and v1
> submission:
> https://lkml.org/lkml/2014/10/13/481
> https://lkml.org/lkml/2014/9/4/496
> ---
> Documentation/ABI/testing/sysfs-gpio | 1 +
> Documentation/gpio/sysfs.txt | 8 ++++
> drivers/gpio/gpiolib-sysfs.c | 77 +++++++++++++++++++++++++++++++++---
> 3 files changed, 80 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-gpio b/Documentation/ABI/testing/sysfs-gpio
> index 80f4c94c7bef..4cc7f4b3f724 100644
> --- a/Documentation/ABI/testing/sysfs-gpio
> +++ b/Documentation/ABI/testing/sysfs-gpio
> @@ -20,6 +20,7 @@ Description:
> /value ... always readable, writes fail for input GPIOs
> /direction ... r/w as: in, out (default low); write: high, low
> /edge ... r/w as: none, falling, rising, both
> + /wakeup ... r/w as: enabled, disabled
> /gpiochipN ... for each gpiochip; #N is its first GPIO
> /base ... (r/o) same as N
> /label ... (r/o) descriptive, not necessarily unique
> diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt
> index c2c3a97f8ff7..f703377d528f 100644
> --- a/Documentation/gpio/sysfs.txt
> +++ b/Documentation/gpio/sysfs.txt
> @@ -97,6 +97,14 @@ and have the following read/write attributes:
> for "rising" and "falling" edges will follow this
> setting.
>
> + "wakeup" ... reads as either "enabled" or "disabled". Write these
> + strings to set/clear the 'wakeup' flag of the IRQ associated
> + with this GPIO. If the IRQ has the 'wakeup' flag set, it can
> + wake the system from sleep states.
> +
> + This file exists only if the pin can generate interrupts and
> + the driver implements the required infrastructure.
> +
> GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the
> controller implementing GPIOs starting at #42) and have the following
> read-only attributes:
> diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
> index 5f2150b619a7..7588b6d5ba94 100644
> --- a/drivers/gpio/gpiolib-sysfs.c
> +++ b/drivers/gpio/gpiolib-sysfs.c
> @@ -286,6 +286,58 @@ found:
>
> static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
>
> +static ssize_t gpio_wakeup_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + ssize_t status;
> + const struct gpio_desc *desc = dev_get_drvdata(dev);
> + int irq = gpiod_to_irq(desc);
> + struct irq_desc *irq_desc = irq_to_desc(irq);
> +
> + mutex_lock(&sysfs_lock);
> +
> + if (irqd_is_wakeup_set(&irq_desc->irq_data))
> + status = sprintf(buf, "enabled\n");
> + else
> + status = sprintf(buf, "disabled\n");
> +
> + mutex_unlock(&sysfs_lock);
> +
> + return status;
> +}
> +
> +static ssize_t gpio_wakeup_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t size)
> +{
> + int ret;
> + unsigned int on;
> + struct gpio_desc *desc = dev_get_drvdata(dev);
> + int irq = gpiod_to_irq(desc);
> +
> + mutex_lock(&sysfs_lock);
> +
> + if (sysfs_streq("enabled", buf)) {
> + on = true;
> + } else if (sysfs_streq("disabled", buf)) {
> + on = false;
> + } else {
> + mutex_unlock(&sysfs_lock);
> + return -EINVAL;
> + }
> +
> + ret = irq_set_irq_wake(irq, on);
> +
> + mutex_unlock(&sysfs_lock);
> +
> + if (ret)
> + pr_warn("%s: failed to %s wake\n", __func__,
> + on ? "enable" : "disable");
> +
> + return size;
> +}
> +
> +static DEVICE_ATTR(wakeup, 0644, gpio_wakeup_show, gpio_wakeup_store);
> +
> static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
> int value)
> {
> @@ -526,7 +578,7 @@ static struct class gpio_class = {
> int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
> {
> unsigned long flags;
> - int status;
> + int status, irq;
> const char *ioname = NULL;
> struct device *dev;
> int offset;
> @@ -582,11 +634,24 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
> goto fail_unregister_device;
> }
>
> - if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
> - !test_bit(FLAG_IS_OUT, &desc->flags))) {
> - status = device_create_file(dev, &dev_attr_edge);
> - if (status)
> - goto fail_unregister_device;
> + irq = gpiod_to_irq(desc);
> + if (irq >= 0) {
> + struct irq_desc *irq_desc = irq_to_desc(irq);
> + struct irq_chip *irqchip = irq_desc_get_chip(irq_desc);
> +
> + if (direction_may_change ||
> + !test_bit(FLAG_IS_OUT, &desc->flags)) {
> + status = device_create_file(dev, &dev_attr_edge);
> + if (status)
> + goto fail_unregister_device;
> + }
> +
> + if (irqchip->flags & IRQCHIP_SKIP_SET_WAKE ||
> + irqchip->irq_set_wake) {
> + status = device_create_file(dev, &dev_attr_wakeup);
> + if (status)
> + goto fail_unregister_device;
> + }
> }
>
> set_bit(FLAG_EXPORT, &desc->flags);
> --
> 2.1.2.1.g5e69ed6
>
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