[Resend,V2] dt: add helper function to read u8 & u16 variables & arrays

Message ID 64c5278ebdec503f83e9b7002bf13affb7f3260f.1351225085.git.viresh.kumar@linaro.org
State Accepted
Headers show

Commit Message

Viresh Kumar Oct. 26, 2012, 4:20 a.m.
This adds following helper routines:
- of_property_read_u8_array()
- of_property_read_u16_array()
- of_property_read_u8()
- of_property_read_u16()

First two actually share most of the code with of_property_read_u32_array(), so
the common part is taken out into a macro, which can be used by all three
*_array() routines.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V1->V2:
-----
- Use typeof() in of_property_read_array() macro instead of passing type to it

 drivers/of/base.c  | 73 +++++++++++++++++++++++++++++++++++++++++++-----------
 include/linux/of.h | 30 ++++++++++++++++++++++
 2 files changed, 89 insertions(+), 14 deletions(-)

Comments

Viresh Kumar Nov. 6, 2012, 11:08 a.m. | #1
On 26 October 2012 09:50, Viresh Kumar <viresh.kumar@linaro.org> wrote:

> This adds following helper routines:
> - of_property_read_u8_array()
> - of_property_read_u16_array()
> - of_property_read_u8()
> - of_property_read_u16()
>
> First two actually share most of the code with
> of_property_read_u32_array(), so
> the common part is taken out into a macro, which can be used by all three
> *_array() routines.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>

Ping!!
Rob Herring Nov. 6, 2012, 2:18 p.m. | #2
On 10/25/2012 11:20 PM, Viresh Kumar wrote:
> This adds following helper routines:
> - of_property_read_u8_array()
> - of_property_read_u16_array()
> - of_property_read_u8()
> - of_property_read_u16()
> 
> First two actually share most of the code with of_property_read_u32_array(), so
> the common part is taken out into a macro, which can be used by all three
> *_array() routines.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> V1->V2:
> -----
> - Use typeof() in of_property_read_array() macro instead of passing type to it
> 
>  drivers/of/base.c  | 73 +++++++++++++++++++++++++++++++++++++++++++-----------
>  include/linux/of.h | 30 ++++++++++++++++++++++
>  2 files changed, 89 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index af3b22a..039e178 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -670,6 +670,64 @@ struct device_node *of_find_node_by_phandle(phandle handle)
>  }
>  EXPORT_SYMBOL(of_find_node_by_phandle);
>  
> +#define of_property_read_array(_np, _pname, _out, _sz)			\
> +	struct property *_prop = of_find_property(_np, _pname, NULL);	\
> +	const __be32 *_val;						\
> +									\
> +	if (!_prop)							\
> +		return -EINVAL;						\
> +	if (!_prop->value)						\
> +		return -ENODATA;					\
> +	if ((_sz * sizeof(*_out)) > _prop->length)			\
> +		return -EOVERFLOW;					\
> +									\
> +	_val = _prop->value;						\
> +	while (_sz--)							\
> +		*_out++ = (typeof(*_out))be32_to_cpup(_val++);		\

This will not work. You are incrementing _out by 1, 2, or 4 bytes, but
_val is always incremented by 4 bytes.

According to the dtc commit adding this feature, the values are packed:

With this patch the following property assignment:

    property = /bits/ 16 <0x1234 0x5678 0x0 0xffff>;

is equivalent to:

    property = <0x12345678 0x0000ffff>;


> +	return 0;
> +
> +/**
> + * 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.
> + * @propname:	name of the property to be searched.
> + * @out_value:	pointer to return value, modified only if return value is 0.
> + *

Missing sz

> + * Search for a property in a device node and read 8-bit value(s) 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 u8 value can be decoded.
> + */
> +int of_property_read_u8_array(const struct device_node *np,
> +			const char *propname, u8 *out_values, size_t sz)
> +{
> +	of_property_read_array(np, propname, out_values, sz);
> +}
> +EXPORT_SYMBOL_GPL(of_property_read_u8_array);
> +
> +/**
> + * of_property_read_u16_array - Find and read an array of u16 from a property.
> + *
> + * @np:		device node from which the property value is to be read.
> + * @propname:	name of the property to be searched.
> + * @out_value:	pointer to return value, modified only if return value is 0.
> + *

Ditto.

> + * Search for a property in a device node and read 16-bit value(s) 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 u16 value can be decoded.
> + */
> +int of_property_read_u16_array(const struct device_node *np,
> +			const char *propname, u16 *out_values, size_t sz)
> +{
> +	of_property_read_array(np, propname, out_values, sz);
> +}
> +EXPORT_SYMBOL_GPL(of_property_read_u16_array);
> +
>  /**
>   * of_property_read_u32_array - Find and read an array of 32 bit integers
>   * from a property.
> @@ -689,20 +747,7 @@ int of_property_read_u32_array(const struct device_node *np,
>  			       const char *propname, u32 *out_values,
>  			       size_t sz)
>  {
> -	struct property *prop = of_find_property(np, propname, NULL);
> -	const __be32 *val;
> -
> -	if (!prop)
> -		return -EINVAL;
> -	if (!prop->value)
> -		return -ENODATA;
> -	if ((sz * sizeof(*out_values)) > prop->length)
> -		return -EOVERFLOW;
> -
> -	val = prop->value;
> -	while (sz--)
> -		*out_values++ = be32_to_cpup(val++);
> -	return 0;
> +	of_property_read_array(np, propname, out_values, sz);
>  }
>  EXPORT_SYMBOL_GPL(of_property_read_u32_array);
>  
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 72843b7..e2d9b40 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -223,6 +223,10 @@ 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_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,
> +			const char *propname, u16 *out_values, size_t sz);
>  extern int of_property_read_u32_array(const struct device_node *np,
>  				      const char *propname,
>  				      u32 *out_values,
> @@ -357,6 +361,18 @@ static inline struct device_node *of_find_compatible_node(
>  	return NULL;
>  }
>  
> +static inline int of_property_read_u8_array(const struct device_node *np,
> +			const char *propname, u8 *out_values, size_t sz)
> +{
> +	return -ENOSYS;
> +}
> +
> +static inline int of_property_read_u16_array(const struct device_node *np,
> +			const char *propname, u16 *out_values, size_t sz)
> +{
> +	return -ENOSYS;
> +}
> +
>  static inline int of_property_read_u32_array(const struct device_node *np,
>  					     const char *propname,
>  					     u32 *out_values, size_t sz)
> @@ -463,6 +479,20 @@ static inline bool of_property_read_bool(const struct device_node *np,
>  	return prop ? true : false;
>  }
>  
> +static inline int of_property_read_u8(const struct device_node *np,
> +				       const char *propname,
> +				       u8 *out_value)
> +{
> +	return of_property_read_u8_array(np, propname, out_value, 1);
> +}
> +
> +static inline int of_property_read_u16(const struct device_node *np,
> +				       const char *propname,
> +				       u16 *out_value)
> +{
> +	return of_property_read_u16_array(np, propname, out_value, 1);
> +}
> +
>  static inline int of_property_read_u32(const struct device_node *np,
>  				       const char *propname,
>  				       u32 *out_value)
>
Viresh Kumar Nov. 6, 2012, 2:39 p.m. | #3
On 6 November 2012 19:48, Rob Herring <robherring2@gmail.com> wrote:

> > diff --git a/drivers/of/base.c b/drivers/of/base.c
>


> > +#define of_property_read_array(_np, _pname, _out, _sz)
>       \
> > +     struct property *_prop = of_find_property(_np, _pname, NULL);   \
> > +     const __be32 *_val;                                             \
> > +                                                                     \
> > +     if (!_prop)                                                     \
> > +             return -EINVAL;                                         \
> > +     if (!_prop->value)                                              \
> > +             return -ENODATA;                                        \
> > +     if ((_sz * sizeof(*_out)) > _prop->length)                      \
> > +             return -EOVERFLOW;                                      \
> > +                                                                     \
> > +     _val = _prop->value;                                            \
> > +     while (_sz--)                                                   \
> > +             *_out++ = (typeof(*_out))be32_to_cpup(_val++);          \
>
> This will not work. You are incrementing _out by 1, 2, or 4 bytes, but
> _val is always incremented by 4 bytes.
>
> According to the dtc commit adding this feature, the values are packed:
>
> With this patch the following property assignment:
>
>     property = /bits/ 16 <0x1234 0x5678 0x0 0xffff>;
>
> is equivalent to:
>
>     property = <0x12345678 0x0000ffff>;
>

Something which i haven't expected :(
I will fix and test it well for all types before sending it now.


> > +/**
> > + * 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.
> > + * @propname:        name of the property to be searched.
> > + * @out_value:       pointer to return value, modified only if return
> value is 0.
> > + *
>
> Missing sz
>

Yes for both misses.

Patch

diff --git a/drivers/of/base.c b/drivers/of/base.c
index af3b22a..039e178 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -670,6 +670,64 @@  struct device_node *of_find_node_by_phandle(phandle handle)
 }
 EXPORT_SYMBOL(of_find_node_by_phandle);
 
+#define of_property_read_array(_np, _pname, _out, _sz)			\
+	struct property *_prop = of_find_property(_np, _pname, NULL);	\
+	const __be32 *_val;						\
+									\
+	if (!_prop)							\
+		return -EINVAL;						\
+	if (!_prop->value)						\
+		return -ENODATA;					\
+	if ((_sz * sizeof(*_out)) > _prop->length)			\
+		return -EOVERFLOW;					\
+									\
+	_val = _prop->value;						\
+	while (_sz--)							\
+		*_out++ = (typeof(*_out))be32_to_cpup(_val++);		\
+	return 0;
+
+/**
+ * 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.
+ * @propname:	name of the property to be searched.
+ * @out_value:	pointer to return value, modified only if return value is 0.
+ *
+ * Search for a property in a device node and read 8-bit value(s) 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 u8 value can be decoded.
+ */
+int of_property_read_u8_array(const struct device_node *np,
+			const char *propname, u8 *out_values, size_t sz)
+{
+	of_property_read_array(np, propname, out_values, sz);
+}
+EXPORT_SYMBOL_GPL(of_property_read_u8_array);
+
+/**
+ * of_property_read_u16_array - Find and read an array of u16 from a property.
+ *
+ * @np:		device node from which the property value is to be read.
+ * @propname:	name of the property to be searched.
+ * @out_value:	pointer to return value, modified only if return value is 0.
+ *
+ * Search for a property in a device node and read 16-bit value(s) 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 u16 value can be decoded.
+ */
+int of_property_read_u16_array(const struct device_node *np,
+			const char *propname, u16 *out_values, size_t sz)
+{
+	of_property_read_array(np, propname, out_values, sz);
+}
+EXPORT_SYMBOL_GPL(of_property_read_u16_array);
+
 /**
  * of_property_read_u32_array - Find and read an array of 32 bit integers
  * from a property.
@@ -689,20 +747,7 @@  int of_property_read_u32_array(const struct device_node *np,
 			       const char *propname, u32 *out_values,
 			       size_t sz)
 {
-	struct property *prop = of_find_property(np, propname, NULL);
-	const __be32 *val;
-
-	if (!prop)
-		return -EINVAL;
-	if (!prop->value)
-		return -ENODATA;
-	if ((sz * sizeof(*out_values)) > prop->length)
-		return -EOVERFLOW;
-
-	val = prop->value;
-	while (sz--)
-		*out_values++ = be32_to_cpup(val++);
-	return 0;
+	of_property_read_array(np, propname, out_values, sz);
 }
 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
 
diff --git a/include/linux/of.h b/include/linux/of.h
index 72843b7..e2d9b40 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -223,6 +223,10 @@  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_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,
+			const char *propname, u16 *out_values, size_t sz);
 extern int of_property_read_u32_array(const struct device_node *np,
 				      const char *propname,
 				      u32 *out_values,
@@ -357,6 +361,18 @@  static inline struct device_node *of_find_compatible_node(
 	return NULL;
 }
 
+static inline int of_property_read_u8_array(const struct device_node *np,
+			const char *propname, u8 *out_values, size_t sz)
+{
+	return -ENOSYS;
+}
+
+static inline int of_property_read_u16_array(const struct device_node *np,
+			const char *propname, u16 *out_values, size_t sz)
+{
+	return -ENOSYS;
+}
+
 static inline int of_property_read_u32_array(const struct device_node *np,
 					     const char *propname,
 					     u32 *out_values, size_t sz)
@@ -463,6 +479,20 @@  static inline bool of_property_read_bool(const struct device_node *np,
 	return prop ? true : false;
 }
 
+static inline int of_property_read_u8(const struct device_node *np,
+				       const char *propname,
+				       u8 *out_value)
+{
+	return of_property_read_u8_array(np, propname, out_value, 1);
+}
+
+static inline int of_property_read_u16(const struct device_node *np,
+				       const char *propname,
+				       u16 *out_value)
+{
+	return of_property_read_u16_array(np, propname, out_value, 1);
+}
+
 static inline int of_property_read_u32(const struct device_node *np,
 				       const char *propname,
 				       u32 *out_value)