[PATCH v4 13/24] fpga: region: add compat_id support

[Wu Hao]

This patch introduces a compat_id member and sysfs interface for each
fpga-region, e.g userspace applications could read the compat_id
from the sysfs interface for compatibility checking before PR.

Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
---
 Documentation/ABI/testing/sysfs-class-fpga-region |  5 +++++
 drivers/fpga/fpga-region.c                        | 19 +++++++++++++++++++
 include/linux/fpga/fpga-region.h                  | 13 +++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-fpga-region

diff --git a/Documentation/ABI/testing/sysfs-class-fpga-region b/Documentation/ABI/testing/sysfs-class-fpga-region
new file mode 100644
index 0000000..419d930
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-fpga-region
@@ -0,0 +1,5 @@
+What:		/sys/class/fpga_region/<region>/compat_id
+Date:		February 2018
+KernelVersion:	4.16
+Contact:	Wu Hao <hao.wu@xxxxxxxxx>
+Description:	FPGA region id for compatibility check.
diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index 660a91b..babec96 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -162,6 +162,24 @@ int fpga_region_program_fpga(struct fpga_region *region)
 }
 EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
 
+static ssize_t compat_id_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct fpga_region *region = to_fpga_region(dev);
+
+	return sprintf(buf, "%016llx%016llx\n",
+		       (unsigned long long)region->compat_id.id_h,
+		       (unsigned long long)region->compat_id.id_l);
+}
+
+static DEVICE_ATTR_RO(compat_id);
+
+static struct attribute *fpga_region_attrs[] = {
+	&dev_attr_compat_id.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(fpga_region);
+
 int fpga_region_register(struct fpga_region *region)
 {
 	struct device *dev = region->parent;
@@ -226,6 +244,7 @@ static int __init fpga_region_init(void)
 	if (IS_ERR(fpga_region_class))
 		return PTR_ERR(fpga_region_class);
 
+	fpga_region_class->dev_groups = fpga_region_groups;
 	fpga_region_class->dev_release = fpga_region_dev_release;
 
 	return 0;
diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
index 423c87e..bf97dcc 100644
--- a/include/linux/fpga/fpga-region.h
+++ b/include/linux/fpga/fpga-region.h
@@ -6,6 +6,17 @@
 #include <linux/fpga/fpga-bridge.h>
 
 /**
+ * struct fpga_region_compat_id - FPGA Region id for compatibility check
+ *
+ * @id_h: high 64bit of the compat_id
+ * @id_l: low 64bit of the compat_id
+ */
+struct fpga_region_compat_id {
+	u64 id_h;
+	u64 id_l;
+};
+
+/**
  * struct fpga_region - FPGA Region structure
  * @dev: FPGA Region device
  * @parent: parent device
@@ -13,6 +24,7 @@
  * @bridge_list: list of FPGA bridges specified in region
  * @mgr: FPGA manager
  * @info: FPGA image info
+ * @compat_id: FPGA region id for compatibility check.
  * @priv: private data
  * @get_bridges: optional function to get bridges to a list
  * @groups: optional attribute groups.
@@ -24,6 +36,7 @@ struct fpga_region {
 	struct list_head bridge_list;
 	struct fpga_manager *mgr;
 	struct fpga_image_info *info;
+	struct fpga_region_compat_id compat_id;
 	void *priv;
 	int (*get_bridges)(struct fpga_region *region);
 	const struct attribute_group **groups;
-- 
2.7.4