[PATCH 3/5] dt-bindings: clk: Add Baikal-T1 System Devices CCU bindings
From: Sergey.Semin
Date: Fri Mar 06 2020 - 08:01:05 EST
From: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
Aside from providing an individual reference clocks for AXI-bus the
Baikal-T1 CCU dividers are used to alter the PLLs output signals for
the SoC peripheral devices. These dividers are represented by means
of the SYS CCU dts-node as an ordinary clock-provider with standard
set of properties supported. In the same way as AXI-bus CCU dividers
do they can be used to reset the APB and SATA clock domains, which
also makes the SYS CCU dts-node to be a reset-controller.
Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alexey Malahov <Alexey.Malahov@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Paul Burton <paulburton@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
---
.../bindings/clock/be,bt1-ccu-sys.yaml | 169 ++++++++++++++++++
include/dt-bindings/clock/bt1-ccu.h | 24 +++
include/dt-bindings/reset/bt1-ccu.h | 4 +
3 files changed, 197 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/be,bt1-ccu-sys.yaml
diff --git a/Documentation/devicetree/bindings/clock/be,bt1-ccu-sys.yaml b/Documentation/devicetree/bindings/clock/be,bt1-ccu-sys.yaml
new file mode 100644
index 000000000000..aea09fbafc89
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/be,bt1-ccu-sys.yaml
@@ -0,0 +1,169 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2019 - 2020 BAIKAL ELECTRONICS, JSC
+#
+# Baikal-T1 System Devices Clocks Control Unit Device Tree Bindings.
+#
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/be,bt1-ccu-sys.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Baikal-T1 System Devices Clock Control Unit
+
+maintainers:
+ - Serge Semin <fancer.lancer@xxxxxxxxx>
+
+description: |
+ Clocks Control Unit is the core of Baikal-T1 SoC responsible for the chip
+ subsystems clocking and resetting. The CCU is connected with an external
+ fixed rate oscillator, which signal is transformed into clocks of various
+ frequencies and then propagated to either individual IP-blocks or to groups
+ of blocks (clock domains). The transformation is done by means of an embedded
+ into CCU PLLs and gateable/non-gateable dividers. APB-bus divider register
+ provides a specific flag to initiate the full APB clock domain reset, so
+ causing each sub-device reset. Baikal-T1 CCU is logically divided into the
+ next components:
+ 1) External oscillator (normally XTAL's 25 MHz crystal oscillator, but
+ in general can provide any frequency supported by the CCU PLLs).
+ 2) PLLs clocks generators (PLLs).
+ 3) AXI-bus clock dividers (AXI).
+ 4) System devices reference clock dividers (SYS) - described in this bindings
+ file.
+ which are connected with each other as shown on the next figure:
+ +---------------+
+ | Baikal-T1 CCU |
+ | +----+------|- MIPS P5600 cores
+ | +-|PLLs|------|- DDR controller
+ | | +----+ |
+ +----+ | | | | |
+ |XTAL|--|-+ | | +---+-|
+ +----+ | | | +-|AXI|-|- AXI-bus
+ | | | +---+-|
+ | | | |
+ | | +----+---+-|- APB-bus
+ | +-------|SYS|-|- Low-speed Devices
+ | +---+-|- High-speed Devices
+ +---------------+
+ Each sub-block is represented as a separate dts-node and has an individual
+ driver to be bound with.
+
+ In order to create signals of wide range frequencies the external oscillator
+ output is primarily connected to a set of CCU PLLs. The PLLs CLKOUT is then
+ either directly connected with the corresponding clocks consumer (like P5600
+ cores or DDR controller) or passed over a CCU divider to create a signal
+ required for the clock domain. The dividers have the following structure
+ +--------------+
+ CLKIN --|->+----+ 1|\ |
+ SETCLK--|--|/DIV|->| | |
+ CLKDIV--|--| | | |-|->CLKLOUT
+ LOCK----|--+----+ | | |
+ | |/ |
+ | | |
+ EN------|-----------+ |
+ RST-----|--------------|->RSTOUT
+ +--------------+
+ where CLKIN is the reference clock coming either from XTAL or from a CCU PLL,
+ SETCLK - a command to update the output clock in accordance with a set
+ divider, CLKDIV - clocks divider, LOCK - a signal of the output clock
+ stabilization, EN - enable/disable the divider block, RST/RSTOUT - reset
+ clocks domain signal. Depending on the consumer IP-core peculiarities the
+ dividers may lack of some functionality depicted on the figure above (like
+ EN, CLKDIV/LOCK/SETCLK or RST). In this case the corresponding clock provider
+ just doesn't expose either switching functions, or the rate configuration, or
+ both of them.
+
+ The clock dividers, which output clock is then consumed by the SoC individual
+ devices, are united into a single clocks provider called System Devices CCU.
+ The System Devices CCU dts-node uses the common clock bindings [1] with no
+ custom properties. The list of exported clocks and reset signals can be found
+ in the files: 'dt-bindings/clock/bt1-ccu.h' and
+ 'dt-bindings/reset/bt1-ccu.h'.
+
+ [1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+allOf:
+ - $ref: /schemas/clock/clock.yaml#
+
+properties:
+ compatible:
+ const: be,bt1-ccu-sys
+
+ reg:
+ items:
+ - description: System Devices CCU sub-block base address.
+ - description: Watchdog clock divider register address in CCU.
+
+ "#clock-cells":
+ description: |
+ Clocks are referenced by the node phandle and an unique identifier
+ from 'dt-bindings/clock/bt1-ccu.h'.
+ const: 1
+
+ "#reset-cells":
+ description: |
+ CCU system devices sub-block provides a reset signal for APB and SATA
+ clock domains, which unique identifiers reside in
+ 'dt-bindings/reset/bt1-ccu.h'.
+ const: 1
+
+ clocks:
+ items:
+ - description: CCU external reference clock.
+ - description: CCU SATA PLL output clock.
+ - description: CCU PCIe PLL output clock.
+ - description: CCU Ethernet PLL output clock.
+
+ clock-names:
+ items:
+ - const: ref_clk
+ - const: sata_clk
+ - const: pcie_clk
+ - const: eth_clk
+
+ clock-output-names: true
+
+ assigned-clocks: true
+
+ assigned-clock-rates: true
+
+additionalProperties: false
+
+required:
+ - compatible
+ - reg
+ - "#clock-cells"
+ - clocks
+ - clock-names
+
+examples:
+ - |
+ #include <dt-bindings/clock/bt1-ccu.h>
+
+ ccu_sys: ccu_sys@1F04D060 {
+ compatible = "be,bt1-ccu-sys";
+ reg = <0x1F04D060 0x0A0>,
+ <0x1F04D150 0x004>;
+ #clock-cells = <1>;
+ #reset-cells = <1>;
+
+ clocks = <&osc25>,
+ <&ccu_pll CCU_SATA_PLL>,
+ <&ccu_pll CCU_PCIE_PLL>,
+ <&ccu_pll CCU_ETH_PLL>;
+ clock-names = "ref_clk", "sata_clk", "pcie_clk",
+ "eth_clk";
+
+ clock-output-names = "sys_sata_ref_clk", "sys_apb_clk",
+ "sys_gmac0_csr_clk", "sys_gmac0_tx_clk",
+ "sys_gmac0_ptp_clk", "sys_gmac1_csr_clk",
+ "sys_gmac1_tx_clk", "sys_gmac1_ptp_clk",
+ "sys_xgmac_ref_clk", "sys_xgmac_ptp_clk",
+ "sys_usb_clk", "sys_pvt_clk",
+ "sys_hwa_clk", "sys_uart_clk",
+ "sys_spi_clk", "sys_i2c1_clk",
+ "sys_i2c2_clk", "sys_gpio_clk",
+ "sys_timer0_clk", "sys_timer1_clk",
+ "sys_timer2_clk", "sys_wdt_clk";
+ };
+...
diff --git a/include/dt-bindings/clock/bt1-ccu.h b/include/dt-bindings/clock/bt1-ccu.h
index ebe723c6e0a8..4dcad1eb721f 100644
--- a/include/dt-bindings/clock/bt1-ccu.h
+++ b/include/dt-bindings/clock/bt1-ccu.h
@@ -27,4 +27,28 @@
#define CCU_AXI_HWA_CLK 9
#define CCU_AXI_SRAM_CLK 10
+/* Baikal-T1 System Devices CCU Clocks indeces. */
+#define CCU_SYS_SATA_REF_CLK 0
+#define CCU_SYS_APB_CLK 1
+#define CCU_SYS_GMAC0_CSR_CLK 2
+#define CCU_SYS_GMAC0_TX_CLK 3
+#define CCU_SYS_GMAC0_PTP_CLK 4
+#define CCU_SYS_GMAC1_CSR_CLK 5
+#define CCU_SYS_GMAC1_TX_CLK 6
+#define CCU_SYS_GMAC1_PTP_CLK 7
+#define CCU_SYS_XGMAC_REF_CLK 8
+#define CCU_SYS_XGMAC_PTP_CLK 9
+#define CCU_SYS_USB_CLK 10
+#define CCU_SYS_PVT_CLK 11
+#define CCU_SYS_HWA_CLK 12
+#define CCU_SYS_UART_CLK 13
+#define CCU_SYS_SPI_CLK 14
+#define CCU_SYS_I2C1_CLK 15
+#define CCU_SYS_I2C2_CLK 16
+#define CCU_SYS_GPIO_CLK 17
+#define CCU_SYS_TIMER0_CLK 18
+#define CCU_SYS_TIMER1_CLK 19
+#define CCU_SYS_TIMER2_CLK 20
+#define CCU_SYS_WDT_CLK 21
+
#endif /* __DT_BINDINGS_CLOCK_BT1_CCU_H */
diff --git a/include/dt-bindings/reset/bt1-ccu.h b/include/dt-bindings/reset/bt1-ccu.h
index 4de5b6bcd433..0bd8fd0edb41 100644
--- a/include/dt-bindings/reset/bt1-ccu.h
+++ b/include/dt-bindings/reset/bt1-ccu.h
@@ -20,4 +20,8 @@
#define CCU_AXI_HWA_RST 9
#define CCU_AXI_SRAM_RST 10
+/* Baikal-T1 System Devices CCU Reset indeces. */
+#define CCU_SYS_SATA_REF_RST 0
+#define CCU_SYS_APB_RST 1
+
#endif /* __DT_BINDINGS_RESET_BT1_CCU_H */
--
2.25.1