Documentation/amdgpu: Add board info details

Add documentation for board info sysfs attribute.
Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Documentation/gpu/amdgpu/driver-misc.rst

@@ -32,6 +32,12 @@ unique_id
 .. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
    :doc: unique_id
 
+board_info
+----------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+   :doc: board_info
+
 Accelerated Processing Units (APU) Info
 ---------------------------------------
 

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -162,6 +162,22 @@ static ssize_t amdgpu_device_get_pcie_replay_count(struct device *dev,
 static DEVICE_ATTR(pcie_replay_count, 0444,
 		amdgpu_device_get_pcie_replay_count, NULL);
 
+/**
+ * DOC: board_info
+ *
+ * The amdgpu driver provides a sysfs API for giving board related information.
+ * It provides the form factor information in the format
+ *
+ *   type : form factor
+ *
+ * Possible form factor values
+ *
+ * - "cem"		- PCIE CEM card
+ * - "oam"		- Open Compute Accelerator Module
+ * - "unknown"	- Not known
+ *
+ */
+
 static ssize_t amdgpu_device_get_board_info(struct device *dev,
 					    struct device_attribute *attr,
 					    char *buf)