From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCHv2 1/7] of: Add support for reading a u32 from a multi-value property. Date: Mon, 15 Apr 2013 11:12:53 +0100 Message-ID: <20130415101253.C22ED3E0AA8@localhost> References: <1364015633-18580-1-git-send-email-linux@prisktech.co.nz> <1364015633-18580-2-git-send-email-linux@prisktech.co.nz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1364015633-18580-2-git-send-email-linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Tony Prisk , Linus Walleij Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org, vt8500-wm8505-linux-kernel-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Sat, 23 Mar 2013 18:13:47 +1300, Tony Prisk wrote: > This patch adds an of_property_read_u32_index() function to allow > reading a single indexed u32 value from a property containing multiple > u32 values. > > Signed-off-by: Tony Prisk > --- > cc: Grant Likely > cc: Rob Herring > cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org > > Hi Rob/Grant, > After a review of my pinctrl driver, it was suggested that one of the helper > functions be moved into the OF subsystem. Could you review and ack this patch > if you're happy with it. Hey Tony, Instead of implementing this as a sparate function, this should be done as an extension to the of_proprety_read_u32_array() interface, just like how of_property_read_u32() is implemented. It will result in less code that way. So, rename of_property_read_u32_array() to __of_property_read_u32() and add a 'index' argument to it. Then of_property_read_u32_index() can be implemented as: static inline int of_property_read_u32_index(const struct device_node *np, const char *propname, int index, u32 *out_value) { return __of_property_read_u32(np, propname, index, 1, out_value); } And the new of_property_read_u32_array() becomes: static inline int of_property_read_u32_array(const struct device_node *np, const char *propname, int sz, u32 *out_value) { return __of_property_read_u32(np, propname, 0, sz, out_value); } g. > Regards > Tony P > > drivers/of/base.c | 33 +++++++++++++++++++++++++++++++++ > include/linux/of.h | 9 +++++++++ > 2 files changed, 42 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 321d3ef..7dc001e 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -746,6 +746,39 @@ struct device_node *of_find_node_by_phandle(phandle handle) > EXPORT_SYMBOL(of_find_node_by_phandle); > > /** > + * of_property_read_u32_index - Find and read a u32 from a multi-value property. > + * > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * @index: index of the u32 in the list of values > + * @out_value: pointer to return value, modified only if no error. > + * > + * Search for a property in a device node and read nth 32-bit value from > + * it. Returns 0 on success, -EINVAL if the property does not exist, > + * -ENODATA if property does not have a value, and -EOVERFLOW if the > + * property data isn't large enough. > + * > + * The out_value is modified only if a valid u32 value can be decoded. > + */ > +int of_property_read_u32_index(const struct device_node *np, > + const char *propname, > + u32 index, u32 *out_value) > +{ > + struct property *prop = of_find_property(np, propname, NULL); > + > + if (!prop) > + return -EINVAL; > + if (!prop->value) > + return -ENODATA; > + if ((index * sizeof(*out_value)) > prop->length) > + return -EOVERFLOW; > + > + *out_value = be32_to_cpup(((__be32 *)prop->value) + index); > + return 0; > +} > +EXPORT_SYMBOL_GPL(of_property_read_u32_index); > + > +/** > * 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 a0f1292..c0747a4 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -235,6 +235,9 @@ extern struct device_node *of_find_node_with_property( > extern struct property *of_find_property(const struct device_node *np, > const char *name, > int *lenp); > +extern int of_property_read_u32_index(const struct device_node *np, > + const char *propname, > + u32 index, u32 *out_value); > 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, > @@ -394,6 +397,12 @@ static inline struct device_node *of_find_compatible_node( > return NULL; > } > > +static inline int of_property_read_u32_index(const struct device_node *np, > + const char *propname, u32 index, u32 *out_value) > +{ > + return -ENOSYS; > +} > + > static inline int of_property_read_u8_array(const struct device_node *np, > const char *propname, u8 *out_values, size_t sz) > { > -- > 1.7.9.5 > -- Grant Likely, B.Sc, P.Eng. 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