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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Aaron Lu <aaron.lu@intel.com>,
	devicetree@vger.kernel.org, Alexandre Courbot <gnurou@gmail.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Bryan Wu <cooloney@gmail.com>,
	Grant Likely <grant.likely@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Darren Hart <dvhart@linux.intel.com>,
	Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH 11/13] gpio: Support for unified device properties interface
Date: Tue, 07 Oct 2014 02:18:08 +0200	[thread overview]
Message-ID: <2052507.JjE2hdgEYc@vostro.rjw.lan> (raw)
In-Reply-To: <2660541.BycO7TFnA2@vostro.rjw.lan>

From: Mika Westerberg <mika.westerberg@linux.intel.com>

Some drivers need to deal with only firmware representation of its
GPIOs. An example would be a GPIO button array driver where each button
is described as a separate firmware node in device tree. Typically these
child nodes do not have physical representation in the Linux device
model.

In order to help device drivers to handle such firmware child nodes we
add dev[m]_get_named_gpiod_from_child() that takes a child firmware
node pointer as its second argument (the first one is the parent device
itself), finds the GPIO using whatever is the underlying firmware
method, and requests the GPIO properly.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/gpio/devres.c         | 34 ++++++++++++++++++++++++++
 drivers/gpio/gpiolib.c        | 56 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/gpio/consumer.h |  5 ++++
 3 files changed, 95 insertions(+)

diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
index 954b9f6..a1f7e55 100644
--- a/drivers/gpio/devres.c
+++ b/drivers/gpio/devres.c
@@ -109,6 +109,40 @@ struct gpio_desc *__must_check __devm_gpiod_get_index(struct device *dev,
 EXPORT_SYMBOL(__devm_gpiod_get_index);
 
 /**
+ * devm_get_named_gpiod_from_child - managed dev_get_named_gpiod_from_child()
+ * @dev:	GPIO consumer
+ * @child:	firmware node (child of @dev)
+ * @propname:	name of the firmware property
+ * @index:	index of the GPIO in the property value in case of many
+ *
+ * GPIO descriptors returned from this function are automatically disposed on
+ * driver detach.
+ */
+struct gpio_desc *devm_get_named_gpiod_from_child(struct device *dev, void *child,
+						  const char *propname, int index)
+{
+	struct gpio_desc **dr;
+	struct gpio_desc *desc;
+
+	dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
+			  GFP_KERNEL);
+	if (!dr)
+		return ERR_PTR(-ENOMEM);
+
+	desc = dev_get_named_gpiod_from_child(dev, child, propname, index);
+	if (IS_ERR(desc)) {
+		devres_free(dr);
+		return desc;
+	}
+
+	*dr = desc;
+	devres_add(dev, dr);
+
+	return desc;
+}
+EXPORT_SYMBOL(devm_get_named_gpiod_from_child);
+
+/**
  * devm_gpiod_get_index_optional - Resource-managed gpiod_get_index_optional()
  * @dev: GPIO consumer
  * @con_id: function within the GPIO consumer
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 4c86601..344bc12 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1717,6 +1717,62 @@ struct gpio_desc *__must_check __gpiod_get_index(struct device *dev,
 EXPORT_SYMBOL_GPL(__gpiod_get_index);
 
 /**
+ * dev_get_named_gpiod_from_child - obtain a GPIO from firmware node
+ * @dev:	parent device
+ * @child:	firmware node (child of @dev)
+ * @propname:	name of the firmware property
+ * @idx:	index of the GPIO in the property value in case of many
+ *
+ * This function can be used for drivers that get their configuration
+ * from firmware in such a way that some properties are described as child
+ * nodes for the parent device in DT or ACPI.
+ *
+ * Function properly finds the corresponding GPIO using whatever is the
+ * underlying firmware interface and then makes sure that the GPIO
+ * descriptor is requested before it is returned to the caller.
+ *
+ * In case of error an ERR_PTR() is returned.
+ */
+struct gpio_desc *dev_get_named_gpiod_from_child(struct device *dev, void *child,
+						 const char *propname, int index)
+{
+	struct gpio_desc *desc = ERR_PTR(-ENODEV);
+	bool active_low = false;
+	int ret;
+
+	if (!child)
+		return ERR_PTR(-EINVAL);
+
+	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
+		enum of_gpio_flags flags;
+
+		desc = of_get_named_gpiod_flags(child, propname, index, &flags);
+		if (!IS_ERR(desc))
+			active_low = flags & OF_GPIO_ACTIVE_LOW;
+	} else if (ACPI_COMPANION(dev)) {
+		struct acpi_gpio_info info;
+
+		desc = acpi_get_gpiod_by_index(child, propname, index, &info);
+		if (!IS_ERR(desc))
+			active_low = info.active_low;
+	}
+
+	if (IS_ERR(desc))
+		return desc;
+
+	ret = gpiod_request(desc, NULL);
+	if (ret)
+		return ERR_PTR(ret);
+
+	/* Only value flag can be set from both DT and ACPI is active_low */
+	if (active_low)
+		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(dev_get_named_gpiod_from_child);
+
+/**
  * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO
  *                            function
  * @dev: GPIO consumer, can be NULL for system-global GPIOs
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 12f146f..033d2fd 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -94,6 +94,11 @@ int gpiod_to_irq(const struct gpio_desc *desc);
 struct gpio_desc *gpio_to_desc(unsigned gpio);
 int desc_to_gpio(const struct gpio_desc *desc);
 
+/* Child properties interface */
+struct gpio_desc *dev_get_named_gpiod_from_child(struct device *dev, void *child,
+						 const char *propname, int index);
+struct gpio_desc *devm_get_named_gpiod_from_child(struct device *dev, void *child,
+						  const char *propname, int index);
 #else /* CONFIG_GPIOLIB */
 
 static inline struct gpio_desc *__must_check __gpiod_get(struct device *dev,
-- 
1.9.3



  parent reply	other threads:[~2014-10-07  0:00 UTC|newest]

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-07  0:10 [PATCH v4 00/13] Add ACPI _DSD and unified device properties support Rafael J. Wysocki
2014-10-07  0:12 ` [PATCH 01/13] ACPI: Add support for device specific properties Rafael J. Wysocki
2014-10-13 12:47   ` Grant Likely
2014-10-07  0:12 ` [PATCH 02/13] Driver core: Unified device properties interface for platform firmware Rafael J. Wysocki
2014-10-07  0:13 ` [PATCH 03/13] ACPI: Allow drivers to match using Device Tree compatible property Rafael J. Wysocki
2014-10-14 13:38   ` Grant Likely
2014-10-07  0:14 ` [PATCH 04/13] ACPI: Document ACPI device specific properties Rafael J. Wysocki
2014-10-13 12:41   ` Grant Likely
2014-10-14  9:42     ` Mika Westerberg
2014-10-07  0:14 ` [PATCH 05/13] misc: at25: Make use of device property API Rafael J. Wysocki
2014-10-07  9:10   ` Geert Uytterhoeven
2014-10-07  9:32     ` Mika Westerberg
2014-10-07  0:15 ` [PATCH 06/13] gpio / ACPI: Add support for _DSD device properties Rafael J. Wysocki
2014-10-14 13:44   ` Grant Likely
2014-10-15  8:46     ` Mika Westerberg
2014-10-07  0:15 ` [PATCH 07/13] gpio: sch: Consolidate core and resume banks Rafael J. Wysocki
2014-10-07  0:16 ` [PATCH 08/13] leds: leds-gpio: Add support for GPIO descriptors Rafael J. Wysocki
2014-10-07  0:16 ` [PATCH 09/12] input: gpio_keys_polled - " Rafael J. Wysocki
2014-10-07 17:29   ` Dmitry Torokhov
2014-10-07  0:17 ` [PATCH 10/13] Driver core: Child node properties for devices Rafael J. Wysocki
2014-10-07  0:18 ` Rafael J. Wysocki [this message]
2014-10-07 10:22   ` [PATCH 11/13] gpio: Support for unified device properties interface Alexandre Courbot
2014-10-07 10:40     ` Mika Westerberg
2014-10-07 10:52       ` Alexandre Courbot
2014-10-08  0:09         ` Rafael J. Wysocki
2014-10-08  2:55           ` Alexandre Courbot
2014-10-08 14:01             ` Rafael J. Wysocki
2014-10-07  0:18 ` [PATCH 12/13] leds: leds-gpio: Make use of device property API Rafael J. Wysocki
2014-10-08 14:04   ` Rafael J. Wysocki
2014-10-08 17:47     ` Bryan Wu
2014-10-08 22:02       ` Rafael J. Wysocki
2014-10-07  0:19 ` [PATCH 13/13] input: gpio_keys_polled - " Rafael J. Wysocki
2014-10-07 17:30   ` Dmitry Torokhov
2014-10-07  0:39 ` [PATCH v4 00/13] Add ACPI _DSD and unified device properties support Rafael J. Wysocki
2014-10-07  2:28 ` Greg Kroah-Hartman
2014-10-15 13:04 ` David Woodhouse
2014-10-15 13:15   ` Mark Rutland
2014-10-15 13:28     ` David Woodhouse
2014-10-15 13:42       ` Mark Rutland
2014-10-15 14:08         ` David Woodhouse
2014-10-15 14:46           ` Darren Hart
2014-10-15 15:11             ` David Woodhouse
2014-10-15 15:17             ` Mark Rutland
2014-10-15 15:43               ` Darren Hart
2014-10-16 10:05                 ` Rafael J. Wysocki
2014-10-16 14:55                 ` David Woodhouse
2014-10-18  8:37                   ` Grant Likely
2014-10-18  8:39                   ` Grant Likely
2014-10-18  8:35                 ` Grant Likely
2014-10-21 21:50                   ` [PATCH v4 00/13] Add ACPI _DSD and unified device properties? support Darren Hart
2015-01-14 18:42     ` [PATCH v4 00/13] Add ACPI _DSD and unified device properties support David Woodhouse
2015-01-15  9:12       ` Rafael J. Wysocki
2014-10-17 12:01 ` [PATCH v5 00/12] " Rafael J. Wysocki
2014-10-17 12:03   ` [PATCH v5 01/12] ACPI: Add support for device specific properties Rafael J. Wysocki
2014-10-17 12:04   ` [PATCH v5 02/12] Driver core: Unified device properties interface for platform firmware Rafael J. Wysocki
2014-10-20  0:07     ` [Update][PATCH " Rafael J. Wysocki
2014-10-17 12:05   ` [PATCH v5 03/12] ACPI: Allow drivers to match using Device Tree compatible property Rafael J. Wysocki
2014-10-20 14:05     ` Grant Likely
2014-10-20 22:19       ` Rafael J. Wysocki
2014-10-17 12:07   ` [PATCH v5 04/12] misc: at25: Make use of device property API Rafael J. Wysocki
2014-10-17 12:09   ` [PATCH v5 05/12] gpio / ACPI: Add support for _DSD device properties Rafael J. Wysocki
2014-10-17 12:10   ` [PATCH v5 06/12] gpio: sch: Consolidate core and resume banks Rafael J. Wysocki
2014-10-17 12:11   ` [PATCH v5 07/12] leds: leds-gpio: Add support for GPIO descriptors Rafael J. Wysocki
2014-10-28 15:26     ` Linus Walleij
2014-10-28 21:56       ` Rafael J. Wysocki
2014-10-29  8:53         ` Mika Westerberg
2014-10-30 15:40           ` Linus Walleij
2014-10-30 16:15             ` Mika Westerberg
2014-10-31  9:41               ` Linus Walleij
2014-10-31  9:55                 ` Mika Westerberg
2014-10-30 15:34         ` Linus Walleij
2014-10-17 12:12   ` [PATCH v5 08/12] input: gpio_keys_polled - " Rafael J. Wysocki
2014-10-17 12:14   ` [PATCH v5 09/12] Driver core: Unified interface for firmware node properties Rafael J. Wysocki
2014-10-18  9:35     ` Arnd Bergmann
2014-10-19 23:30       ` Rafael J. Wysocki
2014-10-20 14:14         ` Arnd Bergmann
2014-10-18 14:55     ` Grant Likely
2014-10-19 23:46       ` Rafael J. Wysocki
2014-10-20 14:18         ` Grant Likely
2014-10-20 22:14           ` Rafael J. Wysocki
2014-10-20 14:19         ` Arnd Bergmann
2014-10-20 14:55           ` Grant Likely
2014-10-20 22:22           ` Rafael J. Wysocki
2014-10-19 22:14     ` Greg Kroah-Hartman
2014-10-19 23:31       ` Rafael J. Wysocki
2014-10-20  0:15     ` [Update][PATCH " Rafael J. Wysocki
2014-10-17 12:16   ` [PATCH v5 10/12] gpio: Support for unified device properties interface Rafael J. Wysocki
2014-10-17 18:09     ` Arnd Bergmann
2014-10-18  9:47       ` Arnd Bergmann
2014-10-19 23:58         ` Rafael J. Wysocki
2014-10-20 14:22           ` Arnd Bergmann
2014-10-20  6:12         ` Alexandre Courbot
2014-10-20 14:26           ` Arnd Bergmann
2014-10-17 12:17   ` [PATCH v5 11/12] leds: leds-gpio: Make use of device property API Rafael J. Wysocki
2014-10-17 12:18   ` [PATCH v5 12/12] input: gpio_keys_polled - " Rafael J. Wysocki
2014-10-17 12:22   ` [PATCH v5 00/12] Add ACPI _DSD and unified device properties support Rafael J. Wysocki
2014-10-17 15:40   ` Greg Kroah-Hartman
2014-10-17 19:23     ` Darren Hart
2014-10-17 21:49     ` Rafael J. Wysocki
2014-10-19 22:14       ` Greg Kroah-Hartman
2014-10-17 18:04   ` Arnd Bergmann
2014-10-17 22:50     ` Rafael J. Wysocki
2014-10-18  8:49       ` Grant Likely
2014-10-19 23:32         ` Rafael J. Wysocki

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