Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751570AbaAPSFY (ORCPT ); Thu, 16 Jan 2014 13:05:24 -0500 Received: from gloria.sntech.de ([95.129.55.99]:49282 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751004AbaAPSFU (ORCPT ); Thu, 16 Jan 2014 13:05:20 -0500 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: Mark Rutland Cc: "linux-arm-kernel@lists.infradead.org" , "arm@kernel.org" , "grant.likely@linaro.org" , Rob Herring , "devicetree@vger.kernel.org" , Philipp Zabel , "linux-kernel@vger.kernel.org" , Greg Kroah-Hartman , Pawel Moll , Stephen Warren , Ian Campbell Subject: [PATCH] of: add function to count number of u32 elements in a property Date: Thu, 16 Jan 2014 19:04:42 +0100 Message-ID: <3781679.27UF2dWtKL@phil> User-Agent: KMail/4.11.3 (Linux/3.11-2-amd64; KDE/4.11.3; x86_64; ; ) In-Reply-To: <20140116124527.GD19578@e106331-lin.cambridge.arm.com> References: <27256277.YJ687suYy5@phil> <1669323.jqjZBfkRx4@phil> <20140116124527.GD19578@e106331-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The need to know the number of array elements in a property is a common pattern. To prevent duplication of open-coded implementations add a helper function that also centralises strict sanity checking and DTB format details. Suggested-by: Mark Rutland Signed-off-by: Heiko Stuebner --- Hi Mark, did you mean it like this? I've tested it with the sram-reserve change and it made the part of the determining the number elements a lot nicer :-) drivers/of/base.c | 32 ++++++++++++++++++++++++++++++++ include/linux/of.h | 8 ++++++++ 2 files changed, 40 insertions(+) diff --git a/drivers/of/base.c b/drivers/of/base.c index f807d0e..0f40ea5 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -920,6 +920,38 @@ int of_property_read_u32_index(const struct device_node *np, EXPORT_SYMBOL_GPL(of_property_read_u32_index); /** + * of_property_count_u32_elems - Count the number of u32 values in a property + * + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * + * Search for a property in a device node and count the number of u32 elements + * in it. Returns number of elements on sucess, -EINVAL if the property does + * not exist or its length does not match a multiple of u32 and -ENODATA if the + * property does not have a value. + */ +int of_property_count_u32_elems(const struct device_node *np, + const char *propname) +{ + int elem_size = sizeof(u32); + int len; + struct property *prop = of_find_property(np, propname, &len); + + if (!prop) + return -EINVAL; + if (!prop->value) + return -ENODATA; + + if (prop->length % elem_size != 0) { + pr_err("size of %s is not a multiple of u32\n", propname); + return -EINVAL; + } + + return len / elem_size; +} +EXPORT_SYMBOL_GPL(of_property_count_u32_elems); + +/** * of_property_read_u8_array - Find and read an array of u8 from a property. * * @np: device node from which the property value is to be read. diff --git a/include/linux/of.h b/include/linux/of.h index 276c546..5794942 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -253,6 +253,8 @@ extern struct property *of_find_property(const struct device_node *np, extern int of_property_read_u32_index(const struct device_node *np, const char *propname, u32 index, u32 *out_value); +extern int of_property_count_u32_elems(const struct device_node *np, + const char *propname); extern int of_property_read_u8_array(const struct device_node *np, const char *propname, u8 *out_values, size_t sz); extern int of_property_read_u16_array(const struct device_node *np, @@ -432,6 +434,12 @@ static inline int of_property_read_u32_index(const struct device_node *np, return -ENOSYS; } +static inline int of_property_count_u32_elems(const struct device_node *np, + const char *propname) +{ + return -ENOSYS; +} + static inline int of_property_read_u8_array(const struct device_node *np, const char *propname, u8 *out_values, size_t sz) { -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/