* Re: [PATCHv2 1/7] of: Add support for reading a u32 from a multi-value property.
[not found] ` <1364015633-18580-2-git-send-email-linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org>
@ 2013-04-15 10:12 ` Grant Likely
0 siblings, 0 replies; 2+ messages in thread
From: Grant Likely @ 2013-04-15 10:12 UTC (permalink / raw)
To: Tony Prisk, Linus Walleij
Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
rob.herring-bsGFqQB8/DxBDgjK7y7TUQ,
vt8500-wm8505-linux-kernel-/JYPxA39Uh5TLH3MbocFFw,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r
On Sat, 23 Mar 2013 18:13:47 +1300, Tony Prisk <linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org> 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 <linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org>
> ---
> cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
> cc: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
> 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.
Secret Lab Technologies, Ltd.
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