[PATCH v2 0/5] gpiolib: convert ACPI gpio helpers to gpiod_ interfaces

[PATCH v2 0/5] gpiolib: convert ACPI gpio helpers to gpiod_ interfaces

[Mika Westerberg]

Hi,

This is an updated version of the patches that convert ACPI GPIO helpers to
the new gpiod_ interfaces. The previous version can be seen here:

 http://www.spinics.net/lists/linux-acpi/msg46542.html

Changes to the previous version:
 * Added check that pin is in range of available pins in acpi_get_gpiod()
 * Dropped acpi_get_gpio()
 * Added acks from Rafael and Alexandre

We still have acpi_get_gpio(d)_by_index() exported outside of gpiolib-acpi.c
but the plan is to get rid of acpi_gpio.h completely in near future.

The series is based on the latest gpiod_ patches from Alexandre Courbot and
tested on Intel Haswell machine.

Mika Westerberg (5):
  gpiolib / ACPI: move acpi_gpiochip_free_interrupts next to the request function
  gpiolib / ACPI: convert to gpiod interfaces
  gpiolib / ACPI: add ACPI support for gpiod_get_index()
  gpiolib / ACPI: allow passing GPIOF_ACTIVE_LOW for GpioInt resources
  gpiolib / ACPI: document the GPIO descriptor based interface

 Documentation/acpi/enumeration.txt |  26 ++++++--
 drivers/gpio/gpiolib-acpi.c        | 129 +++++++++++++++++++------------------
 drivers/gpio/gpiolib.c             |  20 ++++++
 include/linux/acpi_gpio.h          |  31 +++++----
 4 files changed, 127 insertions(+), 79 deletions(-)

-- 
1.8.4.rc3

[PATCH v2 1/5] gpiolib / ACPI: move acpi_gpiochip_free_interrupts next to the request function

[Mika Westerberg]

It makes more sense to have these functions close to each other. No
functional changes.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/gpio/gpiolib-acpi.c | 76 ++++++++++++++++++++++-----------------------
 1 file changed, 38 insertions(+), 38 deletions(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index f2beb72..1745ce5 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -194,6 +194,44 @@ void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 }
 EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
 
+/**
+ * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
+ * @chip:      gpio chip
+ *
+ * Free interrupts associated with the _EVT method for the given GPIO chip.
+ *
+ * The remaining ACPI event interrupts associated with the chip are freed
+ * automatically.
+ */
+void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
+{
+	acpi_handle handle;
+	acpi_status status;
+	struct list_head *evt_pins;
+	struct acpi_gpio_evt_pin *evt_pin, *ep;
+
+	if (!chip->dev || !chip->to_irq)
+		return;
+
+	handle = ACPI_HANDLE(chip->dev);
+	if (!handle)
+		return;
+
+	status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
+	if (ACPI_FAILURE(status))
+		return;
+
+	list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
+		devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
+		list_del(&evt_pin->node);
+		kfree(evt_pin);
+	}
+
+	acpi_detach_data(handle, acpi_gpio_evt_dh);
+	kfree(evt_pins);
+}
+EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);
+
 struct acpi_gpio_lookup {
 	struct acpi_gpio_info info;
 	int index;
@@ -271,41 +309,3 @@ int acpi_get_gpio_by_index(struct device *dev, int index,
 	return lookup.gpio;
 }
 EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index);
-
-/**
- * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
- * @chip:      gpio chip
- *
- * Free interrupts associated with the _EVT method for the given GPIO chip.
- *
- * The remaining ACPI event interrupts associated with the chip are freed
- * automatically.
- */
-void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
-{
-	acpi_handle handle;
-	acpi_status status;
-	struct list_head *evt_pins;
-	struct acpi_gpio_evt_pin *evt_pin, *ep;
-
-	if (!chip->dev || !chip->to_irq)
-		return;
-
-	handle = ACPI_HANDLE(chip->dev);
-	if (!handle)
-		return;
-
-	status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
-	if (ACPI_FAILURE(status))
-		return;
-
-	list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
-		devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
-		list_del(&evt_pin->node);
-		kfree(evt_pin);
-	}
-
-	acpi_detach_data(handle, acpi_gpio_evt_dh);
-	kfree(evt_pins);
-}
-EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);
-- 
1.8.4.rc3

Re: [PATCH v2 1/5] gpiolib / ACPI: move acpi_gpiochip_free_interrupts next to the request function

[Linus Walleij]

On Thu, Oct 10, 2013 at 10:01 AM, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:

> It makes more sense to have these functions close to each other. No
> functional changes.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

So I've applied this first patch, and I'm just waiting for Alexandre's
ACK on the remaining patches concerning gpiod so we get this
100% right.

Yours,
Linus Walleij

Re: [PATCH v2 1/5] gpiolib / ACPI: move acpi_gpiochip_free_interrupts next to the request function

[Alexandre Courbot]

On Fri, Oct 11, 2013 at 4:00 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Thu, Oct 10, 2013 at 10:01 AM, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
>
>> It makes more sense to have these functions close to each other. No
>> functional changes.
>>
>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> So I've applied this first patch, and I'm just waiting for Alexandre's
> ACK on the remaining patches concerning gpiod so we get this
> 100% right.

I think I'm ok with Mika's patches, however I need to send you a new
version of gpiod. I wanted to finish documentation first, but maybe
that can come slightly after so you can at least go ahead with both
series?

Re: [PATCH v2 1/5] gpiolib / ACPI: move acpi_gpiochip_free_interrupts next to the request function

[Linus Walleij]

On Fri, Oct 11, 2013 at 6:42 PM, Alexandre Courbot <gnurou@gmail.com> wrote:
> On Fri, Oct 11, 2013 at 4:00 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
>> On Thu, Oct 10, 2013 at 10:01 AM, Mika Westerberg
>> <mika.westerberg@linux.intel.com> wrote:
>>
>>> It makes more sense to have these functions close to each other. No
>>> functional changes.
>>>
>>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>
>> So I've applied this first patch, and I'm just waiting for Alexandre's
>> ACK on the remaining patches concerning gpiod so we get this
>> 100% right.
>
> I think I'm ok with Mika's patches, however I need to send you a new
> version of gpiod. I wanted to finish documentation first, but maybe
> that can come slightly after so you can at least go ahead with both
> series?

The important thing right now is to get it in a testable form I think?
So that I can throw it at the autobuilder and it gets included into
linux-next as that comes back online.

So give me whatever you have ... BTW is this series dependent on
yours to go in first? Sorry for not seeing the details here...

Yours,
Linus Walleij

Re: [PATCH v2 1/5] gpiolib / ACPI: move acpi_gpiochip_free_interrupts next to the request function

[Mika Westerberg]

On Mon, Oct 14, 2013 at 08:58:05AM +0200, Linus Walleij wrote:
> On Fri, Oct 11, 2013 at 6:42 PM, Alexandre Courbot <gnurou@gmail.com> wrote:
> > On Fri, Oct 11, 2013 at 4:00 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> >> On Thu, Oct 10, 2013 at 10:01 AM, Mika Westerberg
> >> <mika.westerberg@linux.intel.com> wrote:
> >>
> >>> It makes more sense to have these functions close to each other. No
> >>> functional changes.
> >>>
> >>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> >>> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >>
> >> So I've applied this first patch, and I'm just waiting for Alexandre's
> >> ACK on the remaining patches concerning gpiod so we get this
> >> 100% right.
> >
> > I think I'm ok with Mika's patches, however I need to send you a new
> > version of gpiod. I wanted to finish documentation first, but maybe
> > that can come slightly after so you can at least go ahead with both
> > series?
> 
> The important thing right now is to get it in a testable form I think?
> So that I can throw it at the autobuilder and it gets included into
> linux-next as that comes back online.
> 
> So give me whatever you have ... BTW is this series dependent on
> yours to go in first? Sorry for not seeing the details here...

Correct, this series depends on Alexandre's patches.

Re: [PATCH v2 1/5] gpiolib / ACPI: move acpi_gpiochip_free_interrupts next to the request function

[Alexandre Courbot]

On Sun, Oct 13, 2013 at 11:58 PM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> On Fri, Oct 11, 2013 at 6:42 PM, Alexandre Courbot <gnurou@gmail.com> wrote:
>> On Fri, Oct 11, 2013 at 4:00 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
>>> On Thu, Oct 10, 2013 at 10:01 AM, Mika Westerberg
>>> <mika.westerberg@linux.intel.com> wrote:
>>>
>>>> It makes more sense to have these functions close to each other. No
>>>> functional changes.
>>>>
>>>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>>> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>
>>> So I've applied this first patch, and I'm just waiting for Alexandre's
>>> ACK on the remaining patches concerning gpiod so we get this
>>> 100% right.
>>
>> I think I'm ok with Mika's patches, however I need to send you a new
>> version of gpiod. I wanted to finish documentation first, but maybe
>> that can come slightly after so you can at least go ahead with both
>> series?
>
> The important thing right now is to get it in a testable form I think?
> So that I can throw it at the autobuilder and it gets included into
> linux-next as that comes back online.
>
> So give me whatever you have ... BTW is this series dependent on
> yours to go in first? Sorry for not seeing the details here...

Yes it is. I have sent you the v2 of my series last Friday (+ one fix
to squash into 3/3).

[PATCH v2 2/5] gpiolib / ACPI: convert to gpiod interfaces

[Mika Westerberg]

The new GPIO descriptor based interface is now preferred over the old
integer based one. This patch converts the ACPI GPIO helpers to use this
new interface internally. In addition to that provide compatibility
function acpi_get_gpio_by_index() that converts the returned GPIO
descriptor to an integer.

We also drop acpi_get_gpio() as it is not used anywhere outside
gpiolib-acpi and even there we use acpi_get_gpiod() instead.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpio/gpiolib-acpi.c | 51 ++++++++++++++++++++++-----------------------
 include/linux/acpi_gpio.h   | 29 ++++++++++++++++----------
 2 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 1745ce5..03187d0 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -11,7 +11,7 @@
  */
 
 #include <linux/errno.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/export.h>
 #include <linux/acpi_gpio.h>
 #include <linux/acpi.h>
@@ -33,14 +33,15 @@ static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
 }
 
 /**
- * acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number usable with GPIO API
+ * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
  * @path:	ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
  * @pin:	ACPI GPIO pin number (0-based, controller-relative)
  *
- * Returns GPIO number to use with Linux generic GPIO API, or errno error value
+ * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
+ * error value
  */
 
-int acpi_get_gpio(char *path, int pin)
+static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
 {
 	struct gpio_chip *chip;
 	acpi_handle handle;
@@ -48,18 +49,17 @@ int acpi_get_gpio(char *path, int pin)
 
 	status = acpi_get_handle(NULL, path, &handle);
 	if (ACPI_FAILURE(status))
-		return -ENODEV;
+		return ERR_PTR(-ENODEV);
 
 	chip = gpiochip_find(handle, acpi_gpiochip_find);
 	if (!chip)
-		return -ENODEV;
+		return ERR_PTR(-ENODEV);
 
-	if (!gpio_is_valid(chip->base + pin))
-		return -EINVAL;
+	if (pin < 0 || pin > chip->ngpio)
+		return ERR_PTR(-EINVAL);
 
-	return chip->base + pin;
+	return gpio_to_desc(chip->base + pin);
 }
-EXPORT_SYMBOL_GPL(acpi_get_gpio);
 
 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
 {
@@ -235,7 +235,7 @@ EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);
 struct acpi_gpio_lookup {
 	struct acpi_gpio_info info;
 	int index;
-	int gpio;
+	struct gpio_desc *desc;
 	int n;
 };
 
@@ -246,11 +246,11 @@ static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 		return 1;
 
-	if (lookup->n++ == lookup->index && lookup->gpio < 0) {
+	if (lookup->n++ == lookup->index && !lookup->desc) {
 		const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 
-		lookup->gpio = acpi_get_gpio(agpio->resource_source.string_ptr,
-					     agpio->pin_table[0]);
+		lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
+					      agpio->pin_table[0]);
 		lookup->info.gpioint =
 			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 	}
@@ -259,24 +259,24 @@ static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 }
 
 /**
- * acpi_get_gpio_by_index() - get a GPIO number from device resources
+ * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
  * @dev: pointer to a device to get GPIO from
  * @index: index of GpioIo/GpioInt resource (starting from %0)
  * @info: info pointer to fill in (optional)
  *
  * Function goes through ACPI resources for @dev and based on @index looks
- * up a GpioIo/GpioInt resource, translates it to the Linux GPIO number,
+ * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
  * and returns it. @index matches GpioIo/GpioInt resources only so if there
  * are total %3 GPIO resources, the index goes from %0 to %2.
  *
- * If the GPIO cannot be translated or there is an error, negative errno is
+ * If the GPIO cannot be translated or there is an error an ERR_PTR is
  * returned.
  *
  * Note: if the GPIO resource has multiple entries in the pin list, this
  * function only returns the first.
  */
-int acpi_get_gpio_by_index(struct device *dev, int index,
-			   struct acpi_gpio_info *info)
+struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
+					  struct acpi_gpio_info *info)
 {
 	struct acpi_gpio_lookup lookup;
 	struct list_head resource_list;
@@ -285,27 +285,26 @@ int acpi_get_gpio_by_index(struct device *dev, int index,
 	int ret;
 
 	if (!dev)
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 
 	handle = ACPI_HANDLE(dev);
 	if (!handle || acpi_bus_get_device(handle, &adev))
-		return -ENODEV;
+		return ERR_PTR(-ENODEV);
 
 	memset(&lookup, 0, sizeof(lookup));
 	lookup.index = index;
-	lookup.gpio = -ENODEV;
 
 	INIT_LIST_HEAD(&resource_list);
 	ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
 				     &lookup);
 	if (ret < 0)
-		return ret;
+		return ERR_PTR(ret);
 
 	acpi_dev_free_resource_list(&resource_list);
 
-	if (lookup.gpio >= 0 && info)
+	if (lookup.desc && info)
 		*info = lookup.info;
 
-	return lookup.gpio;
+	return lookup.desc ? lookup.desc : ERR_PTR(-ENODEV);
 }
-EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index);
+EXPORT_SYMBOL_GPL(acpi_get_gpiod_by_index);
diff --git a/include/linux/acpi_gpio.h b/include/linux/acpi_gpio.h
index 4c120a1..b6ce601 100644
--- a/include/linux/acpi_gpio.h
+++ b/include/linux/acpi_gpio.h
@@ -2,8 +2,10 @@
 #define _LINUX_ACPI_GPIO_H_
 
 #include <linux/device.h>
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 
 /**
  * struct acpi_gpio_info - ACPI GPIO specific information
@@ -15,23 +17,18 @@ struct acpi_gpio_info {
 
 #ifdef CONFIG_GPIO_ACPI
 
-int acpi_get_gpio(char *path, int pin);
-int acpi_get_gpio_by_index(struct device *dev, int index,
-			   struct acpi_gpio_info *info);
+struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
+					  struct acpi_gpio_info *info);
 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip);
 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip);
 
 #else /* CONFIG_GPIO_ACPI */
 
-static inline int acpi_get_gpio(char *path, int pin)
+static inline struct gpio_desc *
+acpi_get_gpiod_by_index(struct device *dev, int index,
+			struct acpi_gpio_info *info)
 {
-	return -ENODEV;
-}
-
-static inline int acpi_get_gpio_by_index(struct device *dev, int index,
-					 struct acpi_gpio_info *info)
-{
-	return -ENODEV;
+	return ERR_PTR(-ENOSYS);
 }
 
 static inline void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) { }
@@ -39,4 +36,14 @@ static inline void acpi_gpiochip_free_interrupts(struct gpio_chip *chip) { }
 
 #endif /* CONFIG_GPIO_ACPI */
 
+static inline int acpi_get_gpio_by_index(struct device *dev, int index,
+					 struct acpi_gpio_info *info)
+{
+	struct gpio_desc *desc = acpi_get_gpiod_by_index(dev, index, info);
+
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+	return desc_to_gpio(desc);
+}
+
 #endif /* _LINUX_ACPI_GPIO_H_ */
-- 
1.8.4.rc3

[PATCH v2 3/5] gpiolib / ACPI: add ACPI support for gpiod_get_index()

[Mika Westerberg]

gpiod_get_index() and gpiod_get() are now the new preferred way to request
GPIOs. Add support for finding the corresponding GPIO descriptor from ACPI
namespace.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpio/gpiolib.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e2a2cdd..1e099de 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -10,6 +10,7 @@
 #include <linux/seq_file.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
+#include <linux/acpi_gpio.h>
 #include <linux/idr.h>
 #include <linux/slab.h>
 
@@ -2111,6 +2112,12 @@ static struct gpio_desc *of_find_gpio(struct device *dev, const char *id,
 }
 #endif
 
+static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
+					unsigned int idx, unsigned long *flags)
+{
+	return acpi_get_gpiod_by_index(dev, idx, NULL);
+}
+
 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
 				    unsigned int idx, unsigned long *flags)
 {
@@ -2192,6 +2199,9 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
 	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
 		dev_dbg(dev, "using device tree for GPIO lookup\n");
 		desc = of_find_gpio(dev, con_id, idx, &flags);
+	} else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) {
+		dev_dbg(dev, "using ACPI for GPIO lookup\n");
+		desc = acpi_find_gpio(dev, con_id, idx, &flags);
 	} else {
 		dev_dbg(dev, "using lookup tables for GPIO lookup");
 		desc = gpiod_find(dev, con_id, idx, &flags);
-- 
1.8.4.rc3

[PATCH v2 4/5] gpiolib / ACPI: allow passing GPIOF_ACTIVE_LOW for GpioInt resources

[Mika Westerberg]

The ACPI GpioInt resources contain polarity field that is used to specify
whether the interrupt is active high or low. Since gpiolib supports
GPIOF_ACTIVE_LOW we can pass this information in the flags field in
acpi_find_gpio(), analogous to the DeviceTree version.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpio/gpiolib-acpi.c |  2 ++
 drivers/gpio/gpiolib.c      | 12 +++++++++++-
 include/linux/acpi_gpio.h   |  2 ++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 03187d0..ae0ffdc 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -253,6 +253,8 @@ static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 					      agpio->pin_table[0]);
 		lookup->info.gpioint =
 			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
+		lookup->info.active_low =
+			agpio->polarity == ACPI_ACTIVE_LOW;
 	}
 
 	return 1;
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 1e099de..b01a231 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2115,7 +2115,17 @@ static struct gpio_desc *of_find_gpio(struct device *dev, const char *id,
 static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
 					unsigned int idx, unsigned long *flags)
 {
-	return acpi_get_gpiod_by_index(dev, idx, NULL);
+	struct acpi_gpio_info info;
+	struct gpio_desc *desc;
+
+	desc = acpi_get_gpiod_by_index(dev, idx, &info);
+	if (IS_ERR(desc))
+		return desc;
+
+	if (info.gpioint && info.active_low)
+		*flags |= GPIOF_ACTIVE_LOW;
+
+	return desc;
 }
 
 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
diff --git a/include/linux/acpi_gpio.h b/include/linux/acpi_gpio.h
index b6ce601..d875bc3 100644
--- a/include/linux/acpi_gpio.h
+++ b/include/linux/acpi_gpio.h
@@ -10,9 +10,11 @@
 /**
  * struct acpi_gpio_info - ACPI GPIO specific information
  * @gpioint: if %true this GPIO is of type GpioInt otherwise type is GpioIo
+ * @active_low: in case of @gpioint, the pin is active low
  */
 struct acpi_gpio_info {
 	bool gpioint;
+	bool active_low;
 };
 
 #ifdef CONFIG_GPIO_ACPI
-- 
1.8.4.rc3

[PATCH v2 5/5] gpiolib / ACPI: document the GPIO descriptor based interface

[Mika Westerberg]

In addition to the existing ACPI specific GPIO interface, document the new
descriptor based GPIO interface in Documentation/acpi/enumeration.txt, so
it is clear that this new interface is preferred over the ACPI specific
version.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
---
 Documentation/acpi/enumeration.txt | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index aca4e69..b994bcb 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -295,10 +295,6 @@ These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0"
 specifies the path to the controller. In order to use these GPIOs in Linux
 we need to translate them to the Linux GPIO numbers.
 
-The driver can do this by including <linux/acpi_gpio.h> and then calling
-acpi_get_gpio(path, gpio). This will return the Linux GPIO number or
-negative errno if there was no translation found.
-
 In a simple case of just getting the Linux GPIO number from device
 resources one can use acpi_get_gpio_by_index() helper function. It takes
 pointer to the device and index of the GpioIo/GpioInt descriptor in the
@@ -322,3 +318,25 @@ suitable to the gpiolib before passing them.
 
 In case of GpioInt resource an additional call to gpio_to_irq() must be
 done before calling request_irq().
+
+Note that the above API is ACPI specific and not recommended for drivers
+that need to support non-ACPI systems. The recommended way is to use
+the descriptor based GPIO interfaces. The above example looks like this
+when converted to the GPIO desc:
+
+	#include <linux/gpio/consumer.h>
+	...
+
+	struct gpio_desc *irq_desc, *power_desc;
+
+	irq_desc = gpiod_get_index(dev, NULL, 1);
+	if (IS_ERR(irq_desc))
+		/* handle error */
+
+	power_desc = gpiod_get_index(dev, NULL, 0);
+	if (IS_ERR(power_desc))
+		/* handle error */
+
+	/* Now we can use the GPIO descriptors */
+
+See also Documentation/gpio.txt.
-- 
1.8.4.rc3

Re: [PATCH v2 5/5] gpiolib / ACPI: document the GPIO descriptor based interface

[Linus Walleij]

On Thu, Oct 10, 2013 at 10:01 AM, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:

> In addition to the existing ACPI specific GPIO interface, document the new
> descriptor based GPIO interface in Documentation/acpi/enumeration.txt, so
> it is clear that this new interface is preferred over the ACPI specific
> version.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>

I've applied the last 4 of these patches now as well, on top of
Alexandre's gpiod interface. If you can, please test the result
on my "devel" branch and let's see if the autobuilder likes it too...

Yours,
Linus Walleij

Re: [PATCH v2 5/5] gpiolib / ACPI: document the GPIO descriptor based interface

[Mika Westerberg]

On Sat, Oct 19, 2013 at 11:35:39PM +0200, Linus Walleij wrote:
> On Thu, Oct 10, 2013 at 10:01 AM, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> 
> > In addition to the existing ACPI specific GPIO interface, document the new
> > descriptor based GPIO interface in Documentation/acpi/enumeration.txt, so
> > it is clear that this new interface is preferred over the ACPI specific
> > version.
> >
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
> 
> I've applied the last 4 of these patches now as well, on top of
> Alexandre's gpiod interface. If you can, please test the result
> on my "devel" branch and let's see if the autobuilder likes it too...

Just tested using your devel branch and works fine with GPIOs from ACPI
namespace.

Thanks!