dt-bindings: soc: samsung: Add Exynos USI

Add USI bindings documentation and header file. Those are taken from
Linux kernel [1,2], but the documentation was reworked a bit to only
describe the compatibles that will be supported in U-Boot soon.

[1] Documentation/devicetree/bindings/soc/samsung/exynos-usi.yaml
[2] include/dt-bindings/soc/samsung,exynos-usi.h

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

diff --git a/doc/device-tree-bindings/soc/samsung/exynos-usi.yaml b/doc/device-tree-bindings/soc/samsung/exynos-usi.yaml
new file mode 100644 (file)
index 0000000..8e6423f
--- /dev/null
+++ b/doc/device-tree-bindings/soc/samsung/exynos-usi.yaml
@@ -0,0 +1,162 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/samsung/exynos-usi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung's Exynos USI (Universal Serial Interface)
+
+maintainers:
+  - Sam Protsenko <semen.protsenko@linaro.org>
+
+description: |
+  USI IP-core provides selectable serial protocol (UART, SPI or High-Speed I2C).
+  USI shares almost all internal circuits within each protocol, so only one
+  protocol can be chosen at a time. USI is modeled as a node with zero or more
+  child nodes, each representing a serial sub-node device. The mode setting
+  selects which particular function will be used.
+
+properties:
+  $nodename:
+    pattern: "^usi@[0-9a-f]+$"
+
+  compatible:
+    enum:
+      - samsung,exynos850-usi
+
+  reg: true
+
+  clocks: true
+
+  clock-names: true
+
+  ranges: true
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 1
+
+  samsung,sysreg:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      - items:
+          - description: phandle to System Register syscon node
+          - description: offset of SW_CONF register for this USI controller
+    description:
+      Should be phandle/offset pair. The phandle to System Register syscon node
+      (for the same domain where this USI controller resides) and the offset
+      of SW_CONF register for this USI controller.
+
+  samsung,mode:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Selects USI function (which serial protocol to use). Refer to
+      <include/dt-bindings/soc/samsung,exynos-usi.h> for valid USI mode values.
+
+  samsung,clkreq-on:
+    type: boolean
+    description:
+      Enable this property if underlying protocol requires the clock to be
+      continuously provided without automatic gating. As suggested by SoC
+      manual, it should be set in case of SPI/I2C slave, UART Rx and I2C
+      multi-master mode. Usually this property is needed if USI mode is set
+      to "UART".
+
+      This property is optional.
+
+patternProperties:
+  "^i2c@[0-9a-f]+$":
+    $ref: /schemas/i2c/i2c-exynos5.yaml
+    description: Child node describing underlying I2C
+
+  "^serial@[0-9a-f]+$":
+    $ref: /schemas/serial/samsung_uart.yaml
+    description: Child node describing underlying UART/serial
+
+  "^spi@[0-9a-f]+$":
+    $ref: /schemas/spi/samsung,spi.yaml
+    description: Child node describing underlying SPI
+
+required:
+  - compatible
+  - ranges
+  - "#address-cells"
+  - "#size-cells"
+  - samsung,sysreg
+  - samsung,mode
+
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - samsung,exynos850-usi
+
+then:
+  properties:
+    reg:
+      maxItems: 1
+
+    clocks:
+      items:
+        - description: Bus (APB) clock
+        - description: Operating clock for UART/SPI/I2C protocol
+
+    clock-names:
+      items:
+        - const: pclk
+        - const: ipclk
+
+  required:
+    - reg
+    - clocks
+    - clock-names
+
+else:
+  properties:
+    reg: false
+    clocks: false
+    clock-names: false
+    samsung,clkreq-on: false
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/soc/samsung,exynos-usi.h>
+
+    usi0: usi@138200c0 {
+        compatible = "samsung,exynos850-usi";
+        reg = <0x138200c0 0x20>;
+        samsung,sysreg = <&sysreg_peri 0x1010>;
+        samsung,mode = <USI_V2_UART>;
+        samsung,clkreq-on; /* needed for UART mode */
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges;
+        clocks = <&cmu_peri 32>, <&cmu_peri 31>;
+        clock-names = "pclk", "ipclk";
+
+        serial_0: serial@13820000 {
+            compatible = "samsung,exynos850-uart";
+            reg = <0x13820000 0xc0>;
+            interrupts = <GIC_SPI 227 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&cmu_peri 32>, <&cmu_peri 31>;
+            clock-names = "uart", "clk_uart_baud0";
+            status = "disabled";
+        };
+
+        hsi2c_0: i2c@13820000 {
+            compatible = "samsung,exynosautov9-hsi2c";
+            reg = <0x13820000 0xc0>;
+            interrupts = <GIC_SPI 227 IRQ_TYPE_LEVEL_HIGH>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+            clocks = <&cmu_peri 31>, <&cmu_peri 32>;
+            clock-names = "hsi2c", "hsi2c_pclk";
+            status = "disabled";
+        };
+    };

diff --git a/include/dt-bindings/soc/samsung,exynos-usi.h b/include/dt-bindings/soc/samsung,exynos-usi.h
new file mode 100644 (file)
index 0000000..a01af16
--- /dev/null
+++ b/include/dt-bindings/soc/samsung,exynos-usi.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/*
+ * Copyright (c) 2021 Linaro Ltd.
+ * Author: Sam Protsenko <semen.protsenko@linaro.org>
+ *
+ * Device Tree bindings for Samsung Exynos USI (Universal Serial Interface).
+ */
+
+#ifndef __DT_BINDINGS_SAMSUNG_EXYNOS_USI_H
+#define __DT_BINDINGS_SAMSUNG_EXYNOS_USI_H
+
+#define USI_V2_NONE            0
+#define USI_V2_UART            1
+#define USI_V2_SPI             2
+#define USI_V2_I2C             3
+
+#endif /* __DT_BINDINGS_SAMSUNG_EXYNOS_USI_H */