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From:   Samuel Holland <samuel@sholland.org>
To:     Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Rob Herring <robh+dt@kernel.org>
Cc:     Samuel Holland <samuel@sholland.org>, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-sunxi@lists.linux.dev
Subject: [PATCH 1/2] regulator: dt-bindings: Add Allwinner D1 LDOs
Date:   Sun, 31 Jul 2022 23:47:57 -0500
Message-Id: <20220801044758.12679-1-samuel@sholland.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The Allwinner D1 SoC contains two pairs of in-package LDOs. One pair is
for general purpose use. LDOA generally powers the board's 1.8 V rail.
LDOB generally powers the in-package DRAM, where applicable.

The other pair of LDOs powers the analog power domains inside the SoC,
including the audio codec, thermal sensor, and ADCs. These LDOs require
a 0.9 V bandgap voltage reference. The calibration value for the voltage
reference is stored in an eFuse, accessed via an NVMEM cell.

Neither LDO control register is in its own MMIO range; instead, each
regulator device relies on a syscon exported by some "host" device node.
Getting the register via a syscon avoids a dependency on the subsystem/
driver for that host device (e.g. a functioning thermal sensor should
not depend on having the audio codec driver loaded).

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

 .../allwinner,sun20i-d1-analog-ldos.yaml      | 77 +++++++++++++++++++
 .../allwinner,sun20i-d1-system-ldos.yaml      | 55 +++++++++++++
 2 files changed, 132 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-analog-ldos.yaml
 create mode 100644 Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-system-ldos.yaml

diff --git a/Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-analog-ldos.yaml b/Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-analog-ldos.yaml
new file mode 100644
index 000000000000..df648c56123d
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-analog-ldos.yaml
@@ -0,0 +1,77 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/allwinner,sun20i-d1-analog-ldos.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner D1 Analog LDOs
+
+description:
+  Allwinner D1 contains a set of LDOs which are designed to supply analog power
+  inside and outside the SoC. They are controlled by a register within the audio
+  codec MMIO space, but which is not part of the audio codec clock/reset domain,
+  and so is exposed as a syscon.
+
+maintainers:
+  - Samuel Holland <samuel@sholland.org>
+
+properties:
+  compatible:
+    enum:
+      - allwinner,sun20i-d1-analog-ldos
+
+  nvmem-cells:
+    items:
+      - description: NVMEM cell for the calibrated bandgap reference trim value
+
+  nvmem-cell-names:
+    items:
+      - const: bg_trim
+
+  syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: phandle of the device containing the power register
+
+patternProperties:
+  "^(aldo|hpldo)$":
+    type: object
+    $ref: regulator.yaml#
+
+required:
+  - compatible
+  - nvmem-cells
+  - nvmem-cell-names
+  - syscon
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    sid: efuse {
+        #address-cells = <1>;
+        #size-cells = <1>;
+
+        bg_trim: bg-trim@28 {
+            reg = <0x28 0x4>;
+            bits = <16, 8>;
+        };
+    };
+
+    ldos-analog {
+        compatible = "allwinner,sun20i-d1-analog-ldos";
+        nvmem-cells = <&bg_trim>;
+        nvmem-cell-names = "bg_trim";
+        syscon = <&codec>;
+
+        reg_aldo: aldo {
+            regulator-min-microvolt = <1800000>;
+            regulator-max-microvolt = <1800000>;
+        };
+
+        reg_hpldo: hpldo {
+            regulator-min-microvolt = <1800000>;
+            regulator-max-microvolt = <1800000>;
+        };
+    };
+
+...
diff --git a/Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-system-ldos.yaml b/Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-system-ldos.yaml
new file mode 100644
index 000000000000..13b2e8c84f1d
--- /dev/null
+++ b/Documentation/devicetree/bindings/regulator/allwinner,sun20i-d1-system-ldos.yaml
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/allwinner,sun20i-d1-system-ldos.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner D1 System LDOs
+
+description:
+  Allwinner D1 contains a pair of general-purpose LDOs which are designed to
+  supply power inside and outside the SoC. They are controlled by a register
+  within the system controller MMIO space.
+
+maintainers:
+  - Samuel Holland <samuel@sholland.org>
+
+properties:
+  compatible:
+    enum:
+      - allwinner,sun20i-d1-system-ldos
+
+  syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: phandle of the device containing the LDO control register
+
+patternProperties:
+  "^(ldoa|ldob)$":
+    type: object
+    $ref: regulator.yaml#
+
+required:
+  - compatible
+  - syscon
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    ldos-system {
+        compatible = "allwinner,sun20i-d1-system-ldos";
+        syscon = <&syscon>;
+
+        reg_ldoa: ldoa {
+            regulator-min-microvolt = <1800000>;
+            regulator-max-microvolt = <1800000>;
+        };
+
+        reg_ldob: ldob {
+            regulator-name = "vcc-dram";
+            regulator-min-microvolt = <1500000>;
+            regulator-max-microvolt = <1500000>;
+        };
+    };
+
+...
-- 
2.35.1