[PATCH v5 0/3] device property: Add fwnode_get_name() helper

[PATCH v5 0/3] device property: Add fwnode_get_name() helper

[Heikki Krogerus]

Hi,

There are no changes compared to v4. I'm resending because of the
extra patch in v4. Sorry for that. This was the v4 cover letter:

I'm now returning -EOVERFLOW if the buffer is not big enough as
proposed by Andy.

This is the cover letter from v3:

This is the third version of my proposal for this helper. The
second version can be checked here:
https://lkml.org/lkml/2018/11/8/1005

I'm now passing the length as proposed by both Rob and Andy. I'm also
leaving the .get_named_child_node fwnode op untouched.

--
heikki

Heikki Krogerus (3):
  device property: Introduce fwnode_get_name()
  ACPI: property: Add acpi_fwnode_name()
  of/property: Add of_fwnode_name()

 drivers/acpi/property.c  | 28 ++++++++++++++++++++++++++++
 drivers/base/property.c  | 36 ++++++++++++++++++++++++++++++++++++
 drivers/of/property.c    | 13 +++++++++++++
 include/linux/fwnode.h   |  3 +++
 include/linux/property.h |  2 ++
 5 files changed, 82 insertions(+)

-- 
2.19.2

[PATCH v5 1/3] device property: Introduce fwnode_get_name()

[Heikki Krogerus]

This helper returns the name of the node. The name is
primarily expected to be returned from a new fwnode
operation meant for this purpose, but when no name is
returned, the helper will also attempt to read a device
property "name".

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/base/property.c  | 36 ++++++++++++++++++++++++++++++++++++
 include/linux/fwnode.h   |  3 +++
 include/linux/property.h |  2 ++
 3 files changed, 41 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 240ab5230ff6..8bd35b44d9ec 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -1156,6 +1156,42 @@ void fwnode_handle_put(struct fwnode_handle *fwnode)
 }
 EXPORT_SYMBOL_GPL(fwnode_handle_put);
 
+/**
+ * fwnode_get_name - Copy the name of an fwnode to a buffer
+ * @fwnode: Pointer to the node
+ * @buf: Buffer where the name is copied to
+ * @len: Size of the buffer
+ *
+ * Copies the node name of @fwnode to @buf. The routine attempts to first use
+ * the get_name fwnode op of @fwnode, and if it fails, the routine attempts to
+ * read a property "name".
+ *
+ * NOTE: @buf must be large enough to accommodate the name and trailing '\0'.
+ *
+ * Returns 0 on success or errno in case of an error.
+ */
+int fwnode_get_name(const struct fwnode_handle *fwnode, char *buf, size_t len)
+{
+	const char *name;
+	int ret;
+
+	ret = fwnode_call_int_op(fwnode, get_name, buf, len);
+	if (ret == 0 || ret == -EOVERFLOW)
+		return ret;
+
+	ret = fwnode_call_int_op(fwnode, property_read_string_array,
+				 "name", &name, 1);
+	if (ret)
+		return ret;
+
+	if (len < strlen(name) + 1)
+		return -EOVERFLOW;
+
+	sprintf(buf, "%s", name);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_name);
+
 /**
  * fwnode_device_is_available - check if a device is available for use
  * @fwnode: Pointer to the fwnode of the device.
diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index faebf0ca0686..a211b55a5da1 100644
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -52,6 +52,7 @@ struct fwnode_reference_args {
  * struct fwnode_operations - Operations for fwnode interface
  * @get: Get a reference to an fwnode.
  * @put: Put a reference to an fwnode.
+ * @get_name: Get the name of an fwnode
  * @device_get_match_data: Return the device driver match data.
  * @property_present: Return true if a property is present.
  * @property_read_integer_array: Read an array of integer properties. Return
@@ -72,6 +73,8 @@ struct fwnode_reference_args {
 struct fwnode_operations {
 	struct fwnode_handle *(*get)(struct fwnode_handle *fwnode);
 	void (*put)(struct fwnode_handle *fwnode);
+	int (*get_name)(const struct fwnode_handle *fwnode, char *buf,
+			size_t len);
 	bool (*device_is_available)(const struct fwnode_handle *fwnode);
 	const void *(*device_get_match_data)(const struct fwnode_handle *fwnode,
 					     const struct device *dev);
diff --git a/include/linux/property.h b/include/linux/property.h
index ac8a1ebc4c1b..e77f08f49c48 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -109,6 +109,8 @@ struct fwnode_handle *device_get_named_child_node(struct device *dev,
 struct fwnode_handle *fwnode_handle_get(struct fwnode_handle *fwnode);
 void fwnode_handle_put(struct fwnode_handle *fwnode);
 
+int fwnode_get_name(const struct fwnode_handle *fwnode, char *name, size_t len);
+
 int fwnode_irq_get(struct fwnode_handle *fwnode, unsigned int index);
 
 unsigned int device_get_child_node_count(struct device *dev);
-- 
2.19.2

[PATCH v5 2/3] ACPI: property: Add acpi_fwnode_name()

[Heikki Krogerus]

This implements the get_name fwnode op for ACPI.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/acpi/property.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index 8c7c4583b52d..c24cf02e9214 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -1219,6 +1219,33 @@ acpi_graph_get_remote_endpoint(const struct fwnode_handle *__fwnode)
 	return acpi_graph_get_child_prop_value(fwnode, "endpoint", endpoint_nr);
 }
 
+static int
+acpi_fwnode_get_name(const struct fwnode_handle *fwnode, char *buf, size_t len)
+{
+	struct acpi_buffer buffer;
+	acpi_status status;
+
+	if (is_acpi_data_node(fwnode)) {
+		if (len < strlen(to_acpi_data_node(fwnode)->name) + 1)
+			return -EOVERFLOW;
+		sprintf(buf, "%s", to_acpi_data_node(fwnode)->name);
+		return 0;
+	}
+
+	if (len < ACPI_NAME_SIZE + 1)
+		return -EOVERFLOW;
+
+	buffer.length = ACPI_NAME_SIZE + 1;
+	buffer.pointer = buf;
+
+	status = acpi_get_name(to_acpi_device_node(fwnode)->handle,
+			       ACPI_SINGLE_NAME, &buffer);
+	if (ACPI_FAILURE(status))
+		return -ENXIO;
+
+	return 0;
+}
+
 static bool acpi_fwnode_device_is_available(const struct fwnode_handle *fwnode)
 {
 	if (!is_acpi_device_node(fwnode))
@@ -1310,6 +1337,7 @@ acpi_fwnode_device_get_match_data(const struct fwnode_handle *fwnode,
 
 #define DECLARE_ACPI_FWNODE_OPS(ops) \
 	const struct fwnode_operations ops = {				\
+		.get_name = acpi_fwnode_get_name,			\
 		.device_is_available = acpi_fwnode_device_is_available, \
 		.device_get_match_data = acpi_fwnode_device_get_match_data, \
 		.property_present = acpi_fwnode_property_present,	\
-- 
2.19.2

[PATCH v5 3/3] of/property: Add of_fwnode_name()

[Heikki Krogerus]

This implements get_name fwnode op for DT.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/of/property.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index f46828e3b082..403bc9cbbaf4 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -823,6 +823,18 @@ static void of_fwnode_put(struct fwnode_handle *fwnode)
 	of_node_put(to_of_node(fwnode));
 }
 
+static int of_fwnode_get_name(const struct fwnode_handle *fwnode, char *buf,
+			      size_t len)
+{
+	const struct device_node *node = to_of_node(fwnode);
+
+	if (len < snprintf(NULL, 0, "%pOFn", node) + 1)
+		return -EOVERFLOW;
+
+	sprintf(buf, "%pOFn", node);
+	return 0;
+}
+
 static bool of_fwnode_device_is_available(const struct fwnode_handle *fwnode)
 {
 	return of_device_is_available(to_of_node(fwnode));
@@ -987,6 +999,7 @@ of_fwnode_device_get_match_data(const struct fwnode_handle *fwnode,
 const struct fwnode_operations of_fwnode_ops = {
 	.get = of_fwnode_get,
 	.put = of_fwnode_put,
+	.get_name = of_fwnode_get_name,
 	.device_is_available = of_fwnode_device_is_available,
 	.device_get_match_data = of_fwnode_device_get_match_data,
 	.property_present = of_fwnode_property_present,
-- 
2.19.2

Re: [PATCH v5 1/3] device property: Introduce fwnode_get_name()

[Rob Herring]

On Wed, Nov 28, 2018 at 02:59:50PM +0300, Heikki Krogerus wrote:
> This helper returns the name of the node. The name is
> primarily expected to be returned from a new fwnode
> operation meant for this purpose, but when no name is
> returned, the helper will also attempt to read a device
> property "name".
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/base/property.c  | 36 ++++++++++++++++++++++++++++++++++++
>  include/linux/fwnode.h   |  3 +++
>  include/linux/property.h |  2 ++
>  3 files changed, 41 insertions(+)
> 
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index 240ab5230ff6..8bd35b44d9ec 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -1156,6 +1156,42 @@ void fwnode_handle_put(struct fwnode_handle *fwnode)
>  }
>  EXPORT_SYMBOL_GPL(fwnode_handle_put);
>  
> +/**
> + * fwnode_get_name - Copy the name of an fwnode to a buffer
> + * @fwnode: Pointer to the node
> + * @buf: Buffer where the name is copied to
> + * @len: Size of the buffer
> + *
> + * Copies the node name of @fwnode to @buf. The routine attempts to first use
> + * the get_name fwnode op of @fwnode, and if it fails, the routine attempts to
> + * read a property "name".
> + *
> + * NOTE: @buf must be large enough to accommodate the name and trailing '\0'.
> + *
> + * Returns 0 on success or errno in case of an error.
> + */
> +int fwnode_get_name(const struct fwnode_handle *fwnode, char *buf, size_t len)
> +{
> +	const char *name;
> +	int ret;
> +
> +	ret = fwnode_call_int_op(fwnode, get_name, buf, len);
> +	if (ret == 0 || ret == -EOVERFLOW)
> +		return ret;
> +
> +	ret = fwnode_call_int_op(fwnode, property_read_string_array,
> +				 "name", &name, 1);

Do you expect this to work on DT? It does today, but I plan to change 
that. 'name' is a fake property on FDT.

Again, I think this is all working at too low of a level. Name is used 
either for matching or an informational string. For matching, this 
should remain firmware specific. For imformational strings, 
device_node.full_name works.

Rob

Re: [PATCH v5 1/3] device property: Introduce fwnode_get_name()

[Heikki Krogerus]

On Fri, Dec 07, 2018 at 11:24:27AM -0600, Rob Herring wrote:
> On Wed, Nov 28, 2018 at 02:59:50PM +0300, Heikki Krogerus wrote:
> > This helper returns the name of the node. The name is
> > primarily expected to be returned from a new fwnode
> > operation meant for this purpose, but when no name is
> > returned, the helper will also attempt to read a device
> > property "name".
> > 
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > ---
> >  drivers/base/property.c  | 36 ++++++++++++++++++++++++++++++++++++
> >  include/linux/fwnode.h   |  3 +++
> >  include/linux/property.h |  2 ++
> >  3 files changed, 41 insertions(+)
> > 
> > diff --git a/drivers/base/property.c b/drivers/base/property.c
> > index 240ab5230ff6..8bd35b44d9ec 100644
> > --- a/drivers/base/property.c
> > +++ b/drivers/base/property.c
> > @@ -1156,6 +1156,42 @@ void fwnode_handle_put(struct fwnode_handle *fwnode)
> >  }
> >  EXPORT_SYMBOL_GPL(fwnode_handle_put);
> >  
> > +/**
> > + * fwnode_get_name - Copy the name of an fwnode to a buffer
> > + * @fwnode: Pointer to the node
> > + * @buf: Buffer where the name is copied to
> > + * @len: Size of the buffer
> > + *
> > + * Copies the node name of @fwnode to @buf. The routine attempts to first use
> > + * the get_name fwnode op of @fwnode, and if it fails, the routine attempts to
> > + * read a property "name".
> > + *
> > + * NOTE: @buf must be large enough to accommodate the name and trailing '\0'.
> > + *
> > + * Returns 0 on success or errno in case of an error.
> > + */
> > +int fwnode_get_name(const struct fwnode_handle *fwnode, char *buf, size_t len)
> > +{
> > +	const char *name;
> > +	int ret;
> > +
> > +	ret = fwnode_call_int_op(fwnode, get_name, buf, len);
> > +	if (ret == 0 || ret == -EOVERFLOW)
> > +		return ret;
> > +
> > +	ret = fwnode_call_int_op(fwnode, property_read_string_array,
> > +				 "name", &name, 1);
> 
> Do you expect this to work on DT? It does today, but I plan to change 
> that. 'name' is a fake property on FDT.
> 
> Again, I think this is all working at too low of a level. Name is used 
> either for matching or an informational string. For matching, this 
> should remain firmware specific. For imformational strings, 
> device_node.full_name works.

OK, I'll remove call.

thanks,

-- 
heikki