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SubjectRe: [PATCH 2/5] dt-bindings: clk: Add Baikal-T1 AXI-bus CCU bindings
On Fri, Mar 06, 2020 at 04:00:45PM +0300, Sergey.Semin@baikalelectronics.ru wrote:
> From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>
> After being gained by the CCU PLLs the signals must be transformed to
> be suitable for the clock-consumers. This is done by a set of dividers
> embedded into the CCU. A first block of dividers is used to create
> reference clocks for AXI-bus of high-speed peripheral IP-cores of the
> chip. So the AXI-bus CCU dts-node is an ordinary clock-provider with
> standard set of properties supported. But in addition to that each
> AXI-bus clock divider provide a way to reset the corresponding clock
> domain. This makes the AXI-bus CCU dts-node to be also a reset-provider.
>
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: Paul Burton <paulburton@kernel.org>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> ---
> .../bindings/clock/be,bt1-ccu-axi.yaml | 151 ++++++++++++++++++
> include/dt-bindings/clock/bt1-ccu.h | 13 ++
> include/dt-bindings/reset/bt1-ccu.h | 23 +++
> 3 files changed, 187 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/clock/be,bt1-ccu-axi.yaml
> create mode 100644 include/dt-bindings/reset/bt1-ccu.h
>
> diff --git a/Documentation/devicetree/bindings/clock/be,bt1-ccu-axi.yaml b/Documentation/devicetree/bindings/clock/be,bt1-ccu-axi.yaml
> new file mode 100644
> index 000000000000..6b1eefdead27
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/be,bt1-ccu-axi.yaml
> @@ -0,0 +1,151 @@
> +# SPDX-License-Identifier: GPL-2.0

Dual license new bindings:

(GPL-2.0-only OR BSD-2-Clause)

> +#
> +# Copyright (C) 2019 - 2020 BAIKAL ELECTRONICS, JSC
> +#
> +# Baikal-T1 AXI-bus Clocks Control Unit Device Tree Bindings.

As Stephen said, drop this. You can keep the copyright, just make it
line 2.

> +#
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/be,bt1-ccu-axi.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Baikal-T1 AXI-bus Clock Control Unit
> +
> +maintainers:
> + - Serge Semin <fancer.lancer@gmail.com>
> +
> +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. Each clock domain can be
> + also individually reset by using the domain clocks divider configuration
> + registers. 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) - described in this bindings file.
> + 4) System devices reference clock dividers (SYS).
> + 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. Some of PLLs CLKOUT are
> + then passed over CCU dividers to create signals required for the target clock
> + domain (like AXI-bus consumers). 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 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). In this case the corresponding clock provider just
> + doesn't expose either switching functions, or the rate configuration, or
> + both of them.
> +
> + The CCU AXI 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#

Drop this, not needed (clock.yaml is applied to every node).

> +
> +properties:
> + compatible:
> + const: be,bt1-ccu-axi
> +
> + reg:
> + description: AXI-bus CCU dividers sub-block base address.

Don't really need this.

> + maxItems: 1
> +
> + "#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: |
> + AXI-bus CCU sub-block provides a reset signal for each clock domain,
> + which unique identifiers are in 'dt-bindings/reset/bt1-ccu.h'.
> + const: 1
> +
> + clocks:
> + items:
> + - description: CCU SATA PLL output clock.
> + - description: CCU PCIe PLL output clock.
> + - description: CCU Ethernet PLL output clock.
> +
> + clock-names:
> + items:
> + - 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_axi: ccu_axi@1F04D030 {

clock-controller@1f04d030

> + compatible = "be,bt1-ccu-axi";
> + reg = <0x1F04D030 0x030>;
> + #clock-cells = <1>;
> + #reset-cells = <1>;
> +
> + clocks = <&ccu_pll CCU_SATA_PLL>,
> + <&ccu_pll CCU_PCIE_PLL>,
> + <&ccu_pll CCU_ETH_PLL>;
> + clock-names = "sata_clk", "pcie_clk", "eth_clk";
> +
> + clock-output-names = "axi_main_clk", "axi_ddr_clk",
> + "axi_sata_clk", "axi_gmac0_clk",
> + "axi_gmac1_clk", "axi_xgmac_clk",
> + "axi_pcie_m_clk", "axi_pcie_s_clk",
> + "axi_usb_clk", "axi_hwa_clk",
> + "axi_sram_clk";
> + };
> +...
> diff --git a/include/dt-bindings/clock/bt1-ccu.h b/include/dt-bindings/clock/bt1-ccu.h
> index 86e63162ade0..ebe723c6e0a8 100644
> --- a/include/dt-bindings/clock/bt1-ccu.h
> +++ b/include/dt-bindings/clock/bt1-ccu.h
> @@ -14,4 +14,17 @@
> #define CCU_PCIE_PLL 3
> #define CCU_ETH_PLL 4
>
> +/* Baikal-T1 AXI-bus CCU Clocks indeces. */
> +#define CCU_AXI_MAIN_CLK 0
> +#define CCU_AXI_DDR_CLK 1
> +#define CCU_AXI_SATA_CLK 2
> +#define CCU_AXI_GMAC0_CLK 3
> +#define CCU_AXI_GMAC1_CLK 4
> +#define CCU_AXI_XGMAC_CLK 5
> +#define CCU_AXI_PCIE_M_CLK 6
> +#define CCU_AXI_PCIE_S_CLK 7
> +#define CCU_AXI_USB_CLK 8
> +#define CCU_AXI_HWA_CLK 9
> +#define CCU_AXI_SRAM_CLK 10
> +
> #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
> new file mode 100644
> index 000000000000..4de5b6bcd433
> --- /dev/null
> +++ b/include/dt-bindings/reset/bt1-ccu.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2019 BAIKAL ELECTRONICS, JSC
> + *
> + * Baikal-T1 CCU reset indeces.
> + */
> +#ifndef __DT_BINDINGS_RESET_BT1_CCU_H
> +#define __DT_BINDINGS_RESET_BT1_CCU_H
> +
> +/* Baikal-T1 AXI-bus CCU Reset indeces. */
> +#define CCU_AXI_MAIN_RST 0
> +#define CCU_AXI_DDR_RST 1
> +#define CCU_AXI_SATA_RST 2
> +#define CCU_AXI_GMAC0_RST 3
> +#define CCU_AXI_GMAC1_RST 4
> +#define CCU_AXI_XGMAC_RST 5
> +#define CCU_AXI_PCIE_M_RST 6
> +#define CCU_AXI_PCIE_S_RST 7
> +#define CCU_AXI_USB_RST 8
> +#define CCU_AXI_HWA_RST 9
> +#define CCU_AXI_SRAM_RST 10
> +
> +#endif /* __DT_BINDINGS_RESET_BT1_CCU_H */
> --
> 2.25.1
>

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