[PATCH] driver core: property: support for generic property

[Heikki Krogerus]

This extends the unified device property interface by adding
"Generic Property" to it for cases where device tree or ACPI
are not being used.

That makes the unified device property interface cover also
most of the cases where information is extracted from custom
platform_data in the drivers. So if before we had to check
separately is there custom platform_data for a driver:

	if (pdata)
		bar = pdata->bar;
	else
		device_property_read_u32(dev, "foo", &bar);

we can now drop that check and simply always use the unified
device property interface.

That makes it possible to drop a lot of boiler plate from
the drivers, plus quite a few header files under
include/linux/ describing those driver specific platform
data structures can be removed.

Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
---
 drivers/base/property.c  | 135 ++++++++++++++++++++++++++++++++++++++++++-----
 include/linux/device.h   |   3 ++
 include/linux/property.h |  17 ++++++
 3 files changed, 143 insertions(+), 12 deletions(-)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index c458458..4ea6d27 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -15,6 +15,108 @@
 #include <linux/acpi.h>
 #include <linux/of.h>
 
+static struct dev_gen_prop *dev_prop_get(struct device *dev, const char *name)
+{
+	struct dev_gen_prop *prop;
+
+	if (!dev->gen_prop)
+		return NULL;
+
+	for (prop = dev->gen_prop; prop->name; prop++)
+		if (!strcmp(name, prop->name))
+			return prop;
+	return NULL;
+}
+
+static int dev_prop_copy_array_u8(u8 *src, u8 *val, size_t nval)
+{
+	int i;
+
+	for (i = 0; i < nval; i++)
+		val[i] = src[i];
+	return 0;
+}
+
+static int dev_prop_copy_array_u16(u16 *src, u16 *val, size_t nval)
+{
+	int i;
+
+	for (i = 0; i < nval; i++)
+		val[i] = src[i];
+	return 0;
+}
+
+static int dev_prop_copy_array_u32(u32 *src, u32 *val, size_t nval)
+{
+	int i;
+
+	for (i = 0; i < nval; i++)
+		val[i] = src[i];
+	return 0;
+}
+
+static int dev_prop_copy_array_u64(u64 *src, u64 *val, size_t nval)
+{
+	int i;
+
+	for (i = 0; i < nval; i++)
+		val[i] = src[i];
+	return 0;
+}
+
+static int dev_prop_copy_array_string(const char **src, const char **val,
+				      size_t nval)
+{
+	int i;
+
+	for (i = 0; i < nval; i++)
+		val[i] = src[i];
+	return 0;
+}
+
+static int dev_prop_read_array(struct device *dev, const char *name,
+			       enum dev_prop_type type, void *val, size_t nval)
+{
+	struct dev_gen_prop *prop;
+	int ret = 0;
+
+	prop = dev_prop_get(dev, name);
+	if (!prop)
+		return -ENODATA;
+
+	if (prop->type != type)
+		return -EPROTO;
+
+	if (prop->nval < nval)
+		return -EOVERFLOW;
+
+	switch (prop->type) {
+	case DEV_PROP_U8:
+		ret = dev_prop_copy_array_u8((u8 *)prop->num, (u8 *)val,
+					     nval);
+		break;
+	case DEV_PROP_U16:
+		ret = dev_prop_copy_array_u16((u16 *)prop->num, (u16 *)val,
+					      nval);
+		break;
+	case DEV_PROP_U32:
+		ret = dev_prop_copy_array_u32((u32 *)prop->num, (u32 *)val,
+					      nval);
+		break;
+	case DEV_PROP_U64:
+		ret = dev_prop_copy_array_u64(prop->num, (u64 *)val, nval);
+		break;
+	case DEV_PROP_STRING:
+		ret = dev_prop_copy_array_string(prop->str,
+						 (const char **)val, nval);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+
 /**
  * device_property_present - check if a property of a device is present
  * @dev: Device whose property is being checked
@@ -26,8 +128,9 @@ bool device_property_present(struct device *dev, const char *propname)
 {
 	if (IS_ENABLED(CONFIG_OF) && dev->of_node)
 		return of_property_read_bool(dev->of_node, propname);
-
-	return !acpi_dev_prop_get(ACPI_COMPANION(dev), propname, NULL);
+	if (ACPI_HANDLE(dev))
+		return !acpi_dev_prop_get(ACPI_COMPANION(dev), propname, NULL);
+	return !!dev_prop_get(dev, propname);
 }
 EXPORT_SYMBOL_GPL(device_property_present);
 
@@ -55,8 +158,11 @@ EXPORT_SYMBOL_GPL(fwnode_property_present);
 	IS_ENABLED(CONFIG_OF) && _dev_->of_node ? \
 		(OF_DEV_PROP_READ_ARRAY(_dev_->of_node, _propname_, _type_, \
 					_val_, _nval_)) : \
-		acpi_dev_prop_read(ACPI_COMPANION(_dev_), _propname_, \
-				   _proptype_, _val_, _nval_)
+		ACPI_HANDLE(_dev_) ? \
+			acpi_dev_prop_read(ACPI_COMPANION(_dev_), _propname_, \
+					   _proptype_, _val_, _nval_) : \
+			dev_prop_read_array(_dev_, _propname_, _proptype_, \
+					   _val_, _nval_)
 
 /**
  * device_property_read_u8_array - return a u8 array property of a device
@@ -169,10 +275,13 @@ EXPORT_SYMBOL_GPL(device_property_read_u64_array);
 int device_property_read_string_array(struct device *dev, const char *propname,
 				      const char **val, size_t nval)
 {
-	return IS_ENABLED(CONFIG_OF) && dev->of_node ?
-		of_property_read_string_array(dev->of_node, propname, val, nval) :
-		acpi_dev_prop_read(ACPI_COMPANION(dev), propname,
-				   DEV_PROP_STRING, val, nval);
+	if (IS_ENABLED(CONFIG_OF) && dev->of_node)
+		return of_property_read_string_array(dev->of_node, propname,
+						     val, nval);
+	if (ACPI_HANDLE(dev))
+		return acpi_dev_prop_read(ACPI_COMPANION(dev), propname,
+					  DEV_PROP_STRING, val, nval);
+	return dev_prop_read_array(dev, propname, DEV_PROP_STRING, val, nval);
 }
 EXPORT_SYMBOL_GPL(device_property_read_string_array);
 
@@ -193,10 +302,12 @@ EXPORT_SYMBOL_GPL(device_property_read_string_array);
 int device_property_read_string(struct device *dev, const char *propname,
 				const char **val)
 {
-	return IS_ENABLED(CONFIG_OF) && dev->of_node ?
-		of_property_read_string(dev->of_node, propname, val) :
-		acpi_dev_prop_read(ACPI_COMPANION(dev), propname,
-				   DEV_PROP_STRING, val, 1);
+	if (IS_ENABLED(CONFIG_OF) && dev->of_node)
+		return of_property_read_string(dev->of_node, propname, val);
+	if (ACPI_HANDLE(dev))
+		return acpi_dev_prop_read(ACPI_COMPANION(dev), propname,
+					  DEV_PROP_STRING, val, 1);
+	return dev_prop_read_array(dev, propname, DEV_PROP_STRING, val, 1);
 }
 EXPORT_SYMBOL_GPL(device_property_read_string);
 
diff --git a/include/linux/device.h b/include/linux/device.h
index fb50673..738dc25 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -27,6 +27,7 @@
 #include <linux/ratelimit.h>
 #include <linux/uidgid.h>
 #include <linux/gfp.h>
+#include <linux/property.h>
 #include <asm/device.h>
 
 struct device;
@@ -704,6 +705,7 @@ struct acpi_dev_node {
  * @archdata:	For arch-specific additions.
  * @of_node:	Associated device tree node.
  * @acpi_node:	Associated ACPI device node.
+ * @gen_prop:	Generic device property
  * @devt:	For creating the sysfs "dev".
  * @id:		device instance
  * @devres_lock: Spinlock to protect the resource of the device.
@@ -780,6 +782,7 @@ struct device {
 
 	struct device_node	*of_node; /* associated device tree node */
 	struct acpi_dev_node	acpi_node; /* associated ACPI device node */
+	struct dev_gen_prop	*gen_prop; /* generic device property */
 
 	dev_t			devt;	/* dev_t, creates the sysfs "dev" */
 	u32			id;	/* device instance */
diff --git a/include/linux/property.h b/include/linux/property.h
index a6a3d98..44e875f 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -26,6 +26,23 @@ enum dev_prop_type {
 	DEV_PROP_MAX,
 };
 
+/**
+ * struct dev_gen_prop - Generic Device Property
+ * @name: property name
+ * @nval: number of elements in the array
+ * @str: value array of strings
+ * @num: value array of numbers
+ *
+ * Used when of_node and acpi_node are missing.
+ */
+struct dev_gen_prop {
+	enum dev_prop_type type;
+	const char *name;
+	size_t nval;
+	const char **str;
+	u64 *num;
+};
+
 bool device_property_present(struct device *dev, const char *propname);
 int device_property_read_u8_array(struct device *dev, const char *propname,
 				  u8 *val, size_t nval);
-- 
2.1.4


--Nq2Wo0NMKNjxTN9z--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/