Merge branch 'baikal/drivers' into arm/drivers

These are mainly fixups for comments that collided with me
already merging v3 of the series, and one patch that I had forgotten
to pick up.

* baikal/drivers:
  bus: bt1-axi: Build the driver into the kernel
  bus: bt1-apb: Build the driver into the kernel
  bus: bt1-axi: Use sysfs_streq instead of strncmp
  bus: bt1-axi: Optimize the return points in the driver
  bus: bt1-apb: Use sysfs_streq instead of strncmp
  bus: bt1-apb: Use PTR_ERR_OR_ZERO to return from request-regs method
  bus: bt1-apb: Fix show/store callback identations
  bus: bt1-apb: Include linux/io.h
  dt-bindings: memory: Add Baikal-T1 L2-cache Control Block binding

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/memory-controllers/baikal,bt1-l2-ctl.yaml

@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/baikal,bt1-l2-ctl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Baikal-T1 L2-cache Control Block
+
+maintainers:
+  - Serge Semin <fancer.lancer@gmail.com>
+
+description: |
+  By means of the System Controller Baikal-T1 SoC exposes a few settings to
+  tune the MIPS P5600 CM2 L2 cache performance up. In particular it's possible
+  to change the Tag, Data and Way-select RAM access latencies. Baikal-T1
+  L2-cache controller block is responsible for the tuning. Its DT node is
+  supposed to be a child of the system controller.
+
+properties:
+  compatible:
+    const: baikal,bt1-l2-ctl
+
+  reg:
+    maxItems: 1
+
+  baikal,l2-ws-latency:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Cycles of latency for Way-select RAM accesses
+    default: 0
+    minimum: 0
+    maximum: 3
+
+  baikal,l2-tag-latency:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Cycles of latency for Tag RAM accesses
+    default: 0
+    minimum: 0
+    maximum: 3
+
+  baikal,l2-data-latency:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Cycles of latency for Data RAM accesses
+    default: 1
+    minimum: 0
+    maximum: 3
+
+additionalProperties: false
+
+required:
+  - compatible
+
+examples:
+  - |
+    l2@1f04d028 {
+      compatible = "baikal,bt1-l2-ctl";
+      reg = <0x1f04d028 0x004>;
+
+      baikal,l2-ws-latency = <1>;
+      baikal,l2-tag-latency = <1>;
+      baikal,l2-data-latency = <2>;
+    };
+...