From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [RFC PATCH 1/4] acpi: property: Introduce helper acpi_dev_get_reference_device() Date: Wed, 2 Dec 2015 11:20:39 +0200 Message-ID: <20151202092039.GL1593@lahna.fi.intel.com> References: <1449047368-5768-1-git-send-email-wangkefeng.wang@huawei.com> <1449047368-5768-2-git-send-email-wangkefeng.wang@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga09.intel.com ([134.134.136.24]:53708 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756789AbbLBJVQ (ORCPT ); Wed, 2 Dec 2015 04:21:16 -0500 Content-Disposition: inline In-Reply-To: <1449047368-5768-2-git-send-email-wangkefeng.wang@huawei.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Kefeng Wang Cc: "Rafael J. Wysocki" , Arnd Bergmann , Hanjun Guo , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org On Wed, Dec 02, 2015 at 05:09:25PM +0800, Kefeng Wang wrote: > Like of_parse_phandle() helper function to read and parse a phandle property > and return a pointer to the resulting device_node, introduce helper function > acpi_dev_get_reference_device() to read and parse a device properties(used in > _DSD method) and return a pointer to the resulting acpi_device. > > Signed-off-by: Kefeng Wang > --- > drivers/acpi/property.c | 23 +++++++++++++++++++++++ > include/linux/acpi.h | 7 +++++++ > 2 files changed, 30 insertions(+) > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c > index 88f4306..e2e7754 100644 > --- a/drivers/acpi/property.c > +++ b/drivers/acpi/property.c > @@ -398,6 +398,29 @@ int acpi_dev_get_property(struct acpi_device *adev, const char *name, > } > EXPORT_SYMBOL_GPL(acpi_dev_get_property); > > +/** > + * acpi_dev_get_reference_device - return the acpi_device referenced > + * @adev: ACPI device to get the property from. > + * @name: Name of the property. > + * @index: Index of the reference to return > + * > + * Returns referenced ACPI device pointer, or NULL if not found > + */ > +struct acpi_device *acpi_dev_get_reference_device(struct acpi_device *adev, > + const char *name, size_t index) > +{ > + struct acpi_reference_args args; > + int ret; > + > + ret = acpi_node_get_property_reference(acpi_fwnode_handle(adev), name, index, &args); > + > + if (ret) > + return NULL; > + > + return args.adev; > +} > +EXPORT_SYMBOL(acpi_dev_get_reference_device); This wrapper looks pretty useless honestly. Why not use acpi_node_get_property_reference() directly if you need to get the device reference? Also you should use EXPORT_SYMBOL_GPL() here.