drm/doc: Add amdgpu hwmon/power documentation (v2)

Document the hwmon and power control interfaces exposed
by the amdgpu driver.

v2: use section rather than chapter for now

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Documentation/gpu/amdgpu.rst

@@ -61,3 +61,56 @@ Interrupt Handling
 
 .. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
    :internal:
+
+GPU Power/Thermal Controls and Monitoring
+=========================================
+
+This section covers hwmon and power/thermal controls.
+
+HWMON Interfaces
+----------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+   :doc: hwmon
+
+GPU sysfs Power State Interfaces
+--------------------------------
+
+GPU power controls are exposed via sysfs files.
+
+power_dpm_state
+~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+   :doc: power_dpm_state
+
+power_dpm_force_performance_level
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+   :doc: power_dpm_force_performance_level
+
+pp_table
+~~~~~~~~
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+   :doc: pp_table
+
+pp_od_clk_voltage
+~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+   :doc: pp_od_clk_voltage
+
+pp_dpm_sclk pp_dpm_mclk pp_dpm_pcie
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+   :doc: pp_dpm_sclk pp_dpm_mclk pp_dpm_pcie
+
+pp_power_profile_mode
+~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+   :doc: pp_power_profile_mode
+