dt-bindings: PCI: dwc: Add clocks/resets common properties

DW PCIe RP/EP reference manuals explicit define all the clocks and reset
requirements in [1] and [2]. Seeing the DW PCIe vendor-specific
DT-bindings have already started assigning random names to the same set of
the clocks and resets lines, let's define a generic names sets and add
them to the DW PCIe common DT-schema.

Note since there are DW PCI-based vendor-specific DT-bindings with the
custom names assigned to the same clocks and resets resources we have no
much choice but to add them to the generic DT-schemas in order to have the
schemas being applicable for such devices. These names are marked as
vendor-specific and should be avoided being used in new bindings in favor
of the generic names.

[1] Synopsys DesignWare Cores PCI Express Controller Databook - DWC PCIe
Root Port, Version 5.40a, March 2019, p.55 - 78.
[2] Synopsys DesignWare Cores PCI Express Controller Databook - DWC PCIe
Endpoint, Version 5.40a, March 2019, p.58 - 81.

Link: https://lore.kernel.org/r/20221113191301.5526-12-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/snps,dw-pcie-common.yaml

@@ -58,6 +58,126 @@ properties:
     minItems: 1
     maxItems: 26
 
+  clocks:
+    description:
+      DWC PCIe reference manual explicitly defines a set of the clocks required
+      to get the controller working correctly. In general all of them can
+      be divided into two groups':' application and core clocks. Note the
+      platforms may have some of the clock sources unspecified in case if the
+      corresponding domains are fed up from a common clock source.
+    minItems: 1
+    maxItems: 7
+
+  clock-names:
+    minItems: 1
+    maxItems: 7
+    items:
+      oneOf:
+        - description:
+            Data Bus Interface (DBI) clock. Clock signal for the AXI-bus
+            interface of the Configuration-Dependent Module, which is
+            basically the set of the controller CSRs.
+          const: dbi
+        - description:
+            Application AXI-bus Master interface clock. Basically this is
+            a clock for the controller DMA interface (PCI-to-CPU).
+          const: mstr
+        - description:
+            Application AXI-bus Slave interface clock. This is a clock for
+            the CPU-to-PCI memory IO interface.
+          const: slv
+        - description:
+            Controller Core-PCS PIPE interface clock. It's normally
+            supplied by an external PCS-PHY.
+          const: pipe
+        - description:
+            Controller Primary clock. It's assumed that all controller input
+            signals (except resets) are synchronous to this clock.
+          const: core
+        - description:
+            Auxiliary clock for the controller PMC domain. The controller
+            partitioning implies having some parts to operate with this
+            clock in some power management states.
+          const: aux
+        - description:
+            Generic reference clock. In case if there are several
+            interfaces fed up with a common clock source it's advisable to
+            define it with this name (for instance pipe, core and aux can
+            be connected to a single source of the periodic signal).
+          const: ref
+        - description:
+            Clock for the PHY registers interface. Originally this is
+            a PHY-viewport-based interface, but some platform may have
+            specifically designed one.
+          const: phy_reg
+        - description:
+            Vendor-specific clock names. Consider using the generic names
+            above for new bindings.
+          oneOf:
+            - description: See native 'dbi' clock for details
+              enum: [ pcie, pcie_apb_sys, aclk_dbi ]
+            - description: See native 'mstr/slv' clock for details
+              enum: [ pcie_bus, pcie_inbound_axi, pcie_aclk, aclk_mst, aclk_slv ]
+            - description: See native 'pipe' clock for details
+              enum: [ pcie_phy, pcie_phy_ref, link ]
+            - description: See native 'aux' clock for details
+              enum: [ pcie_aux ]
+            - description: See native 'ref' clock for details.
+              enum: [ gio ]
+            - description: See nativs 'phy_reg' clock for details
+              enum: [ pcie_apb_phy, pclk ]
+
+  resets:
+    description:
+      DWC PCIe reference manual explicitly defines a set of the reset
+      signals required to be de-asserted to properly activate the controller
+      sub-parts. All of these signals can be divided into two sub-groups':'
+      application and core resets with respect to the main sub-domains they
+      are supposed to reset. Note the platforms may have some of these signals
+      unspecified in case if they are automatically handled or aggregated into
+      a comprehensive control module.
+    minItems: 1
+    maxItems: 10
+
+  reset-names:
+    minItems: 1
+    maxItems: 10
+    items:
+      oneOf:
+        - description: Data Bus Interface (DBI) domain reset
+          const: dbi
+        - description: AXI-bus Master interface reset
+          const: mstr
+        - description: AXI-bus Slave interface reset
+          const: slv
+        - description: Application-dependent interface reset
+          const: app
+        - description: Controller Non-sticky CSR flags reset
+          const: non-sticky
+        - description: Controller sticky CSR flags reset
+          const: sticky
+        - description: PIPE-interface (Core-PCS) logic reset
+          const: pipe
+        - description:
+            Controller primary reset (resets everything except PMC module)
+          const: core
+        - description: PCS/PHY block reset
+          const: phy
+        - description: PMC hot reset signal
+          const: hot
+        - description: Cold reset signal
+          const: pwr
+        - description:
+            Vendor-specific reset names. Consider using the generic names
+            above for new bindings.
+          oneOf:
+            - description: See native 'app' reset for details
+              enum: [ apps, gio, apb ]
+            - description: See native 'phy' reset for details
+              enum: [ pciephy, link ]
+            - description: See native 'pwr' reset for details
+              enum: [ turnoff ]
+
   phys:
     description:
       There can be up to the number of possible lanes PHYs specified placed in

Documentation/devicetree/bindings/pci/snps,dw-pcie-ep.yaml

@@ -180,6 +180,12 @@ examples:
       interrupts = <23>, <24>;
       interrupt-names = "dma0", "dma1";
 
+      clocks = <&sys_clk 12>, <&sys_clk 24>;
+      clock-names = "dbi", "ref";
+
+      resets = <&sys_rst 12>, <&sys_rst 24>;
+      reset-names = "dbi", "phy";
+
       phys = <&pcie_phy0>, <&pcie_phy1>, <&pcie_phy2>, <&pcie_phy3>;
       phy-names = "pcie0", "pcie1", "pcie2", "pcie3";
 

Documentation/devicetree/bindings/pci/snps,dw-pcie.yaml

@@ -195,8 +195,6 @@ properties:
       - contains:
           const: msi
 
-  clocks: true
-
 additionalProperties: true
 
 required: