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* [PATCH v3 0/4] clk: Add Baikal-T1 SoC Clock Control Unit support
@ 2020-05-26 22:20 Serge Semin
  2020-05-26 22:20 ` [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding Serge Semin
                   ` (3 more replies)
  0 siblings, 4 replies; 11+ messages in thread
From: Serge Semin @ 2020-05-26 22:20 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Stephen Boyd, Michael Turquette
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Maxim Kaurkin,
	Pavel Parkhomenko, Ramil Zaripov, Ekaterina Skachko,
	Vadim Vlasov, Alexey Kolotnikov, Arnd Bergmann, Rob Herring,
	linux-clk, linux-mips, devicetree, linux-kernel

Stephen, Michael, the merge window is upon us, please review/merge in/whatever
this patchset.

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 PLLs and
gateable/non-gateable, fixed/variable dividers embedded into the CCU. There
are five PLLs to create a clock for the MIPS P5600 cores, the embedded DDR
controller, SATA, Ethernet and PCIe domains. The last three PLLs CLKOUT are
then passed over CCU dividers to create signals required for the target clock
domains: individual AXI and APB bus clocks, SoC devices reference clocks.
The CCU divider registers may also provide a way to reset the target devices
state.

So this patchset introduces the Baikal-T1 clock and reset drivers of CCU
PLLs, AXI-bus clock dividers and system devices clock dividers.

This patchset is rebased and tested on the mainline Linux kernel 5.7-rc4:
0e698dfa2822 ("Linux 5.7-rc4")
tag: v5.7-rc4

Changelog v2:
- Rearrange the SoBs.
- Discard comments in the binding files headers.
- Add dual GPL/BSD license to the bindings.
- Add spaces around the ASCII-graphics in the bindings description.
- Discard redundant dt objects check against "/schemas/clock/clock.yaml#"
  schema.
- Discard redundant descriptions of the "#clock-cells" and "#reset-cells"
  properties in dt bindings schema.
- Discard "reg" property since the CCU dividers DT nodes are supposed be
  children of the syscon-compatible system controller node.
- Remove "clock-output-names" property support.
- Replace "additionalProperties: false" with "unevaluatedProperties: false"
  in the bindings.
- Lowercase the nodes name in the binding examples.
- Use "clock-controller" node name suffix in the binding examples.
- Remove unnecessary comments in the clocks and resets dt-binding header
  files.
- Don't enable the CCU clock drivers by default for COMPILE_TEST config.
- Make sure the CCU drivers depend on OF kernel config only when built for
  Baikal-T1-based platform.
- Fix spelling in the CCU PLL and Dividers kernel configs description.
- Replace lock delay and frequency calculation macros with inline functions.
- Use 64-bits arithmetics in the CCU PLL frequency calculation function.
- Use FIELD_{GET,PREP}() macro instead of handwritten field setters and
  getters.
- Discard CLK_IGNORE_UNUSED flag setting. It's redundant since CLK_IS_CRITICAL
  is enough for cases when it's appropriate.
- Comment out the CLK_IS_CRITICAL flag settings.
- Discard !pll and !div tests from ccu_pll_hw_unregister() and ccu_div_get_clk_id()
  methods respectively.
- Discard alive probe messages.
- Convert the drivers to using syscon regmap instead of direct IO methods,
  since now the PLLs DT node is supposed to be a sub-node of the Baikal-T1
  System Controller node.
- Add DebugFS nodes in RO-mode by default.

Link: https://lore.kernel.org/linux-clk/20200506222300.30895-1-Sergey.Semin@baikalelectronics.ru/
Changelog v3:
- Get the reg property back to the DT bindings even though the driver is
  using the parental syscon regmap.
- The DT schema will live separately from the system controller, but the
  corresponding sub-node of the later DT schema will $ref this one.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Maxim Kaurkin <Maxim.Kaurkin@baikalelectronics.ru>
Cc: Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>
Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Cc: Ekaterina Skachko <Ekaterina.Skachko@baikalelectronics.ru>
Cc: Vadim Vlasov <V.Vlasov@baikalelectronics.ru>
Cc: Alexey Kolotnikov <Alexey.Kolotnikov@baikalelectronics.ru>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-clk@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Serge Semin (4):
  dt-bindings: clk: Add Baikal-T1 CCU PLLs binding
  dt-bindings: clk: Add Baikal-T1 CCU Dividers binding
  clk: Add Baikal-T1 CCU PLLs driver
  clk: Add Baikal-T1 CCU Dividers driver

 .../bindings/clock/baikal,bt1-ccu-div.yaml    | 188 ++++++
 .../bindings/clock/baikal,bt1-ccu-pll.yaml    | 131 ++++
 drivers/clk/Kconfig                           |   1 +
 drivers/clk/Makefile                          |   1 +
 drivers/clk/baikal-t1/Kconfig                 |  42 ++
 drivers/clk/baikal-t1/Makefile                |   3 +
 drivers/clk/baikal-t1/ccu-div.c               | 602 ++++++++++++++++++
 drivers/clk/baikal-t1/ccu-div.h               | 110 ++++
 drivers/clk/baikal-t1/ccu-pll.c               | 558 ++++++++++++++++
 drivers/clk/baikal-t1/ccu-pll.h               |  64 ++
 drivers/clk/baikal-t1/clk-ccu-div.c           | 487 ++++++++++++++
 drivers/clk/baikal-t1/clk-ccu-pll.c           | 204 ++++++
 include/dt-bindings/clock/bt1-ccu.h           |  48 ++
 include/dt-bindings/reset/bt1-ccu.h           |  25 +
 14 files changed, 2464 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/baikal,bt1-ccu-div.yaml
 create mode 100644 Documentation/devicetree/bindings/clock/baikal,bt1-ccu-pll.yaml
 create mode 100644 drivers/clk/baikal-t1/Kconfig
 create mode 100644 drivers/clk/baikal-t1/Makefile
 create mode 100644 drivers/clk/baikal-t1/ccu-div.c
 create mode 100644 drivers/clk/baikal-t1/ccu-div.h
 create mode 100644 drivers/clk/baikal-t1/ccu-pll.c
 create mode 100644 drivers/clk/baikal-t1/ccu-pll.h
 create mode 100644 drivers/clk/baikal-t1/clk-ccu-div.c
 create mode 100644 drivers/clk/baikal-t1/clk-ccu-pll.c
 create mode 100644 include/dt-bindings/clock/bt1-ccu.h
 create mode 100644 include/dt-bindings/reset/bt1-ccu.h

-- 
2.26.2


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding
  2020-05-26 22:20 [PATCH v3 0/4] clk: Add Baikal-T1 SoC Clock Control Unit support Serge Semin
@ 2020-05-26 22:20 ` Serge Semin
  2020-05-29 17:54   ` Rob Herring
  2020-05-30 18:14   ` Stephen Boyd
  2020-05-26 22:20 ` [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding Serge Semin
                   ` (2 subsequent siblings)
  3 siblings, 2 replies; 11+ messages in thread
From: Serge Semin @ 2020-05-26 22:20 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Stephen Boyd, Michael Turquette, Rob Herring
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	linux-mips, linux-clk, devicetree, linux-kernel

Baikal-T1 Clocks Control Unit is responsible for transformation of a
signal coming from an external oscillator into clocks of various
frequencies to propagate them then to the corresponding clocks
consumers (either individual IP-blocks or clock domains). In order
to create a set of high-frequency clocks the external signal is
firstly handled by the embedded into CCU PLLs. So the corresponding
dts-node is just a normal clock-provider node with standard set of
properties. Note as being part of the Baikal-T1 System Controller its
DT node is supposed to be a child the system controller node.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-mips@vger.kernel.org

---

Changelog v2:
- Rearrange the SoBs.
- Discard comments in the bindings file header.
- Add dual GPL/BSD license.
- Add spaces around the ASCII-graphics in the binding description.
- Remove reference to Documentation/devicetree/bindings/clock/clock-bindings.txt
  file.
- Discard redundant object check against "/schemas/clock/clock.yaml#" schema.
- Discard redundant descriptions of the "#clock-cells" property.
- Remove "reg" property since from now the clock DT node is supposed to be
  a child of the syscon-compatible system controller node.
- Remove "clock-output-names" property support.
- Replace "additionalProperties: false" with "unevaluatedProperties: false".
- Lowercase the nodes name in the examples.
- Use "clock-controller" node name suffix in the examples.
- Remove unnecessary comments in the clocks dt-bindings header file.

Changelog v3:
- Get the reg property back even though the driver is using the parental
  syscon regmap.
- The DT schema will live separately from the system controller, but the
  corresponding sub-node of the later DT schema will $ref this one.
---
 .../bindings/clock/baikal,bt1-ccu-pll.yaml    | 131 ++++++++++++++++++
 include/dt-bindings/clock/bt1-ccu.h           |  16 +++
 2 files changed, 147 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/baikal,bt1-ccu-pll.yaml
 create mode 100644 include/dt-bindings/clock/bt1-ccu.h

diff --git a/Documentation/devicetree/bindings/clock/baikal,bt1-ccu-pll.yaml b/Documentation/devicetree/bindings/clock/baikal,bt1-ccu-pll.yaml
new file mode 100644
index 000000000000..97131bfa6f87
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/baikal,bt1-ccu-pll.yaml
@@ -0,0 +1,131 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/baikal,bt1-ccu-pll.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Baikal-T1 Clock Control Unit PLL
+
+maintainers:
+  - Serge Semin <fancer.lancer@gmail.com>
+
+description: |
+  Clocks Control Unit is the core of Baikal-T1 SoC System Controller
+  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 PLLs and gateable/non-gateable dividers embedded into the CCU.
+  It's 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) - described in this binding file.
+  3) AXI-bus clock dividers (AXI).
+  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 CCU 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. There are five PLLs
+  to create a clock for the MIPS P5600 cores, the embedded DDR controller,
+  SATA, Ethernet and PCIe domains. The last three domains though named by the
+  biggest system interfaces in fact include nearly all of the rest SoC
+  peripherals. Each of the PLLs is based on True Circuits TSMC CLN28HPM core
+  with an interface wrapper (so called safe PLL' clocks switcher) to simplify
+  the PLL configuration procedure. The PLLs work as depicted on the next
+  diagram:
+
+      +--------------------------+
+      |                          |
+      +-->+---+    +---+   +---+ |  +---+   0|\
+  CLKF--->|/NF|--->|PFD|...|VCO|-+->|/OD|--->| |
+          +---+ +->+---+   +---+ /->+---+    | |--->CLKOUT
+  CLKOD---------C----------------+          1| |
+       +--------C--------------------------->|/
+       |        |                             ^
+  Rclk-+->+---+ |                             |
+  CLKR--->|/NR|-+                             |
+          +---+                               |
+  BYPASS--------------------------------------+
+  BWADJ--->
+
+  where Rclk is the reference clock coming  from XTAL, NR - reference clock
+  divider, NF - PLL clock multiplier, OD - VCO output clock divider, CLKOUT -
+  output clock, BWADJ is the PLL bandwidth adjustment parameter. At this moment
+  the binding supports the PLL dividers configuration in accordance with a
+  requested rate, while bypassing and bandwidth adjustment settings can be
+  added in future if it gets to be necessary.
+
+  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 CCU PLL dts-node uses the common clock bindings with no custom
+  parameters. The list of exported clocks can be found in
+  'include/dt-bindings/clock/bt1-ccu.h'. Since CCU PLL is a part of the
+  Baikal-T1 SoC System Controller its DT node is supposed to be a child of
+  later one.
+
+properties:
+  compatible:
+    const: baikal,bt1-ccu-pll
+
+  reg:
+    maxItems: 1
+
+  "#clock-cells":
+    const: 1
+
+  clocks:
+    description: External reference clock
+    maxItems: 1
+
+  clock-names:
+    const: ref_clk
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - "#clock-cells"
+  - clocks
+  - clock-names
+
+examples:
+  # Clock Control Unit PLL node:
+  - |
+    clock-controller@1f04d000 {
+      compatible = "baikal,bt1-ccu-pll";
+      reg = <0x1f04d000 0x028>;
+      #clock-cells = <1>;
+
+      clocks = <&clk25m>;
+      clock-names = "ref_clk";
+    };
+  # Required external oscillator:
+  - |
+    clk25m: clock-oscillator-25m {
+      compatible = "fixed-clock";
+      #clock-cells = <0>;
+      clock-frequency  = <25000000>;
+      clock-output-names = "clk25m";
+    };
+...
diff --git a/include/dt-bindings/clock/bt1-ccu.h b/include/dt-bindings/clock/bt1-ccu.h
new file mode 100644
index 000000000000..931a4bea67c0
--- /dev/null
+++ b/include/dt-bindings/clock/bt1-ccu.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Baikal-T1 CCU clock indices
+ */
+#ifndef __DT_BINDINGS_CLOCK_BT1_CCU_H
+#define __DT_BINDINGS_CLOCK_BT1_CCU_H
+
+#define CCU_CPU_PLL			0
+#define CCU_SATA_PLL			1
+#define CCU_DDR_PLL			2
+#define CCU_PCIE_PLL			3
+#define CCU_ETH_PLL			4
+
+#endif /* __DT_BINDINGS_CLOCK_BT1_CCU_H */
-- 
2.26.2


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding
  2020-05-26 22:20 [PATCH v3 0/4] clk: Add Baikal-T1 SoC Clock Control Unit support Serge Semin
  2020-05-26 22:20 ` [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding Serge Semin
@ 2020-05-26 22:20 ` Serge Semin
  2020-05-29 17:55   ` Rob Herring
  2020-05-30 18:14   ` Stephen Boyd
  2020-05-26 22:20 ` [PATCH v3 3/4] clk: Add Baikal-T1 CCU PLLs driver Serge Semin
  2020-05-26 22:20 ` [PATCH v3 4/4] clk: Add Baikal-T1 CCU Dividers driver Serge Semin
  3 siblings, 2 replies; 11+ messages in thread
From: Serge Semin @ 2020-05-26 22:20 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Stephen Boyd, Michael Turquette,
	Rob Herring, Philipp Zabel
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	linux-mips, linux-clk, devicetree, linux-kernel

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. The second block dividers alter the PLLs output signals to be then
consumed by SoC peripheral devices. Both block DT nodes are ordinary
clock-providers with standard set of properties supported. But in addition
to that each clock provider can be used to reset the corresponding clock
domain. This makes the AXI-bus and System Devices CCU DT nodes to be also
reset-providers.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-mips@vger.kernel.org

---

Changelog v2:
- Rearrange the SoBs.
- Combine AXI-bus and System Devices CCU bindings into a single file.
- Discard comments in the bindings file header.
- Add dual GPL/BSD license.
- Add spaces around the ASCII-graphics in the binding description.
- Remove reference to Documentation/devicetree/bindings/clock/clock-bindings.txt
  file.
- Discard redundant object check against "/schemas/clock/clock.yaml#" schema.
- Discard redundant descriptions of "#clock-cells" and "#reset-cells"
  properties.
- Discard "reg" property since the CCU dividers DT nodes are supposed be
  children of the syscon-compatible system controller node.
- Remove "clock-output-names" property support.
- Replace "additionalProperties: false" with "unevaluatedProperties: false".
- Lowercase the nodes name in the examples.
- Use "clock-controller" node name suffix in the examples.
- Remove unnecessary comments in the clocks and resets dt-binding header
  files.
- Discard label definitions in the examples.

Changelog v3:
- Get the reg property back even though the driver is using the parental
  syscon regmap.
- The DT schema will live separately from the system controller, but the
  corresponding sub-node of the later DT schema will $ref this one.
---
 .../bindings/clock/baikal,bt1-ccu-div.yaml    | 188 ++++++++++++++++++
 include/dt-bindings/clock/bt1-ccu.h           |  32 +++
 include/dt-bindings/reset/bt1-ccu.h           |  25 +++
 3 files changed, 245 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/baikal,bt1-ccu-div.yaml
 create mode 100644 include/dt-bindings/reset/bt1-ccu.h

diff --git a/Documentation/devicetree/bindings/clock/baikal,bt1-ccu-div.yaml b/Documentation/devicetree/bindings/clock/baikal,bt1-ccu-div.yaml
new file mode 100644
index 000000000000..2821425ee445
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/baikal,bt1-ccu-div.yaml
@@ -0,0 +1,188 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/baikal,bt1-ccu-div.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Baikal-T1 Clock Control Unit Dividers
+
+maintainers:
+  - Serge Semin <fancer.lancer@gmail.com>
+
+description: |
+  Clocks Control Unit is the core of Baikal-T1 SoC System Controller
+  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. The
+  later ones are described in this binding. 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 binding file.
+  4) System devices reference clock dividers (SYS) - described in this binding
+     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 DT 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 or System Device 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 CCU PLLs or from an
+  external clock oscillator, 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 clock dividers, which output clock is then consumed by the SoC individual
+  devices, are united into a single clocks provider called System Devices CCU.
+  Similarly the dividers with output clocks utilized as AXI-bus reference clocks
+  are called AXI-bus CCU. Both of them use the common clock bindings with no
+  custom properties. The list of exported clocks and reset signals can be found
+  in the files: 'include/dt-bindings/clock/bt1-ccu.h' and
+  'include/dt-bindings/reset/bt1-ccu.h'. Since System Devices and AXI-bus CCU
+  are a part of the Baikal-T1 SoC System Controller their DT nodes are supposed
+  to be a children of later one.
+
+if:
+  properties:
+    compatible:
+      contains:
+        const: baikal,bt1-ccu-axi
+
+then:
+  properties:
+    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
+
+else:
+  properties:
+    clocks:
+      items:
+        - description: 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
+
+properties:
+  compatible:
+    enum:
+      - baikal,bt1-ccu-axi
+      - baikal,bt1-ccu-sys
+
+  reg:
+    maxItems: 1
+
+  "#clock-cells":
+    const: 1
+
+  "#reset-cells":
+    const: 1
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - "#clock-cells"
+  - clocks
+  - clock-names
+
+examples:
+  # AXI-bus Clock Control Unit node:
+  - |
+    #include <dt-bindings/clock/bt1-ccu.h>
+
+    clock-controller@1f04d030 {
+      compatible = "baikal,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";
+    };
+  # System Devices Clock Control Unit node:
+  - |
+    #include <dt-bindings/clock/bt1-ccu.h>
+
+    clock-controller@1f04d060 {
+      compatible = "baikal,bt1-ccu-sys";
+      reg = <0x1f04d060 0x0a0>;
+      #clock-cells = <1>;
+      #reset-cells = <1>;
+
+      clocks = <&clk25m>,
+               <&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";
+    };
+  # Required Clock Control Unit PLL node:
+  - |
+    ccu_pll: clock-controller@1f04d000 {
+      compatible = "baikal,bt1-ccu-pll";
+      reg = <0x1f04d000 0x028>;
+      #clock-cells = <1>;
+
+      clocks = <&clk25m>;
+      clock-names = "ref_clk";
+    };
+...
diff --git a/include/dt-bindings/clock/bt1-ccu.h b/include/dt-bindings/clock/bt1-ccu.h
index 931a4bea67c0..5f166d27a00a 100644
--- a/include/dt-bindings/clock/bt1-ccu.h
+++ b/include/dt-bindings/clock/bt1-ccu.h
@@ -13,4 +13,36 @@
 #define CCU_PCIE_PLL			3
 #define CCU_ETH_PLL			4
 
+#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
+
+#define CCU_SYS_SATA_REF_CLK		0
+#define CCU_SYS_APB_CLK			1
+#define CCU_SYS_GMAC0_TX_CLK		2
+#define CCU_SYS_GMAC0_PTP_CLK		3
+#define CCU_SYS_GMAC1_TX_CLK		4
+#define CCU_SYS_GMAC1_PTP_CLK		5
+#define CCU_SYS_XGMAC_REF_CLK		6
+#define CCU_SYS_XGMAC_PTP_CLK		7
+#define CCU_SYS_USB_CLK			8
+#define CCU_SYS_PVT_CLK			9
+#define CCU_SYS_HWA_CLK			10
+#define CCU_SYS_UART_CLK		11
+#define CCU_SYS_I2C1_CLK		12
+#define CCU_SYS_I2C2_CLK		13
+#define CCU_SYS_GPIO_CLK		14
+#define CCU_SYS_TIMER0_CLK		15
+#define CCU_SYS_TIMER1_CLK		16
+#define CCU_SYS_TIMER2_CLK		17
+#define CCU_SYS_WDT_CLK			18
+
 #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..3578e83026bc
--- /dev/null
+++ b/include/dt-bindings/reset/bt1-ccu.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Baikal-T1 CCU reset indices
+ */
+#ifndef __DT_BINDINGS_RESET_BT1_CCU_H
+#define __DT_BINDINGS_RESET_BT1_CCU_H
+
+#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
+
+#define CCU_SYS_SATA_REF_RST		0
+#define CCU_SYS_APB_RST			1
+
+#endif /* __DT_BINDINGS_RESET_BT1_CCU_H */
-- 
2.26.2


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v3 3/4] clk: Add Baikal-T1 CCU PLLs driver
  2020-05-26 22:20 [PATCH v3 0/4] clk: Add Baikal-T1 SoC Clock Control Unit support Serge Semin
  2020-05-26 22:20 ` [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding Serge Semin
  2020-05-26 22:20 ` [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding Serge Semin
@ 2020-05-26 22:20 ` Serge Semin
  2020-05-30 18:14   ` Stephen Boyd
  2020-05-26 22:20 ` [PATCH v3 4/4] clk: Add Baikal-T1 CCU Dividers driver Serge Semin
  3 siblings, 1 reply; 11+ messages in thread
From: Serge Semin @ 2020-05-26 22:20 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Stephen Boyd, Michael Turquette
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	Rob Herring, linux-mips, devicetree, linux-kernel, linux-clk

Baikal-T1 is supposed to be supplied with a high-frequency external
oscillator. But in order to create signals suitable for each IP-block
embedded into the SoC the oscillator output is primarily connected to
a set of CCU PLLs. There are five of them to create clocks for the MIPS
P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains.
The last three domains though named by the biggest system interfaces in
fact include nearly all of the rest SoC peripherals. Each of the PLLs is
based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper
(so called safe PLL' clocks switcher) to simplify the PLL configuration
procedure.

This driver creates the of-based hardware clocks to use them then in
the corresponding subsystems. In order to simplify the driver code we
split the functionality up into the PLLs clocks operations and hardware
clocks declaration/registration procedures.

Even though the PLLs are based on the same IP-core, they may have some
differences. In particular, some CCU PLLs support the output clock change
without gating them (like CPU or PCIe PLLs), while the others don't, some
CCU PLLs are critical and aren't supposed to be gated. In order to cover
all of these cases the hardware clocks driver is designed with an
info-descriptor pattern. So there are special static descriptors declared
for each PLL, which is then used to create a hardware clock with proper
operations. Additionally debugfs-files are provided for each PLL' field
to make sure the implemented rate-PLLs-dividers calculation algorithm is
correct.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org

---

Changelog v2:
- Rearrange the SoBs.
- Don't enable the CCU clock drivers by default for COMPILE_TEST config.
- Make sure the CCU drivers depend on OF kernel config only when built for
  Baikal-T1-based platform.
- Fix spelling in the CCU PLL kernel config description.
- Replace lock delay and frequency calculation macro with inline functions.
- Use 64-bits arithmetics in the PLL output frequency calculation method.
- Use readl_poll_timeout_atomic() to poll the PLL lock state.
- Use FIELD_{GET,PREP}() macro instead of handwritten field setters and
  getters.
- Discard CLK_IGNORE_UNUSED flag setting. It's redundant since CLK_IS_CRITICAL
  is enough for cases when it's appropriate.
- Don't declare private copies of the Common Clock Flags.
- Comment out the CLK_IS_CRITICAL flag settings.
- Discard !pll test in ccu_pll_hw_unregister() method.
- Discard ccu_pll_get_clk_id() method. Use not-null check instead of FFs-
  based invalid ID value.
- Discard alive probe message.
- Remove "clock-output-names" property support.
- Convert the driver to using syscon regmap instead of direct IO methods,
  since now the PLLs DT node is supposed to be a sub-node of the Baikal-T1
  System Controller node.
- Add DebugFS nodes in RO-mode by default.
---
 drivers/clk/Kconfig                 |   1 +
 drivers/clk/Makefile                |   1 +
 drivers/clk/baikal-t1/Kconfig       |  30 ++
 drivers/clk/baikal-t1/Makefile      |   2 +
 drivers/clk/baikal-t1/ccu-pll.c     | 558 ++++++++++++++++++++++++++++
 drivers/clk/baikal-t1/ccu-pll.h     |  64 ++++
 drivers/clk/baikal-t1/clk-ccu-pll.c | 204 ++++++++++
 7 files changed, 860 insertions(+)
 create mode 100644 drivers/clk/baikal-t1/Kconfig
 create mode 100644 drivers/clk/baikal-t1/Makefile
 create mode 100644 drivers/clk/baikal-t1/ccu-pll.c
 create mode 100644 drivers/clk/baikal-t1/ccu-pll.h
 create mode 100644 drivers/clk/baikal-t1/clk-ccu-pll.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index bcb257baed06..b32da34ebcf9 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -341,6 +341,7 @@ config COMMON_CLK_FIXED_MMIO
 
 source "drivers/clk/actions/Kconfig"
 source "drivers/clk/analogbits/Kconfig"
+source "drivers/clk/baikal-t1/Kconfig"
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
 source "drivers/clk/imgtec/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index f4169cc2fd31..1496045d4e01 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -75,6 +75,7 @@ obj-y					+= analogbits/
 obj-$(CONFIG_COMMON_CLK_AT91)		+= at91/
 obj-$(CONFIG_ARCH_ARTPEC)		+= axis/
 obj-$(CONFIG_ARC_PLAT_AXS10X)		+= axs10x/
+obj-$(CONFIG_CLK_BAIKAL_T1)		+= baikal-t1/
 obj-y					+= bcm/
 obj-$(CONFIG_ARCH_BERLIN)		+= berlin/
 obj-$(CONFIG_ARCH_DAVINCI)		+= davinci/
diff --git a/drivers/clk/baikal-t1/Kconfig b/drivers/clk/baikal-t1/Kconfig
new file mode 100644
index 000000000000..00398ee916dc
--- /dev/null
+++ b/drivers/clk/baikal-t1/Kconfig
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config CLK_BAIKAL_T1
+	bool "Baikal-T1 Clocks Control Unit interface"
+	depends on (MIPS_BAIKAL_T1 && OF) || COMPILE_TEST
+	default MIPS_BAIKAL_T1
+	help
+	  Clocks Control Unit is the core of Baikal-T1 SoC System Controller
+	  responsible for the chip subsystems clocking and resetting. It
+	  consists of multiple global clock domains, which can be reset by
+	  means of the CCU control registers. These domains and devices placed
+	  in them are fed with clocks generated by a hierarchy of PLLs,
+	  configurable and fixed clock dividers. Enable this option to be able
+	  to select Baikal-T1 CCU PLLs and Dividers drivers.
+
+if CLK_BAIKAL_T1
+
+config CLK_BT1_CCU_PLL
+	bool "Baikal-T1 CCU PLLs support"
+	select MFD_SYSCON
+	default MIPS_BAIKAL_T1
+	help
+	  Enable this to support the PLLs embedded into the Baikal-T1 SoC
+	  System Controller. These are five PLLs placed at the root of the
+	  clocks hierarchy, right after an external reference oscillator
+	  (normally of 25MHz). They are used to generate high frequency
+	  signals, which are either directly wired to the consumers (like
+	  CPUs, DDR, etc.) or passed over the clock dividers to be only
+	  then used as an individual reference clock of a target device.
+
+endif
diff --git a/drivers/clk/baikal-t1/Makefile b/drivers/clk/baikal-t1/Makefile
new file mode 100644
index 000000000000..4a612bbacc37
--- /dev/null
+++ b/drivers/clk/baikal-t1/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_CLK_BT1_CCU_PLL) += ccu-pll.o clk-ccu-pll.o
diff --git a/drivers/clk/baikal-t1/ccu-pll.c b/drivers/clk/baikal-t1/ccu-pll.c
new file mode 100644
index 000000000000..758393122d2f
--- /dev/null
+++ b/drivers/clk/baikal-t1/ccu-pll.c
@@ -0,0 +1,558 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Authors:
+ *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
+ *   Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
+ *
+ * Baikal-T1 CCU PLL interface driver
+ */
+
+#define pr_fmt(fmt) "bt1-ccu-pll: " fmt
+
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/limits.h>
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include <linux/regmap.h>
+#include <linux/iopoll.h>
+#include <linux/time64.h>
+#include <linux/rational.h>
+#include <linux/debugfs.h>
+
+#include "ccu-pll.h"
+
+#define CCU_PLL_CTL			0x000
+#define CCU_PLL_CTL_EN			BIT(0)
+#define CCU_PLL_CTL_RST			BIT(1)
+#define CCU_PLL_CTL_CLKR_FLD		2
+#define CCU_PLL_CTL_CLKR_MASK		GENMASK(7, CCU_PLL_CTL_CLKR_FLD)
+#define CCU_PLL_CTL_CLKF_FLD		8
+#define CCU_PLL_CTL_CLKF_MASK		GENMASK(20, CCU_PLL_CTL_CLKF_FLD)
+#define CCU_PLL_CTL_CLKOD_FLD		21
+#define CCU_PLL_CTL_CLKOD_MASK		GENMASK(24, CCU_PLL_CTL_CLKOD_FLD)
+#define CCU_PLL_CTL_BYPASS		BIT(30)
+#define CCU_PLL_CTL_LOCK		BIT(31)
+#define CCU_PLL_CTL1			0x004
+#define CCU_PLL_CTL1_BWADJ_FLD		3
+#define CCU_PLL_CTL1_BWADJ_MASK		GENMASK(14, CCU_PLL_CTL1_BWADJ_FLD)
+
+#define CCU_PLL_LOCK_CHECK_RETRIES	50
+
+#define CCU_PLL_NR_MAX \
+	((CCU_PLL_CTL_CLKR_MASK >> CCU_PLL_CTL_CLKR_FLD) + 1)
+#define CCU_PLL_NF_MAX \
+	((CCU_PLL_CTL_CLKF_MASK >> (CCU_PLL_CTL_CLKF_FLD + 1)) + 1)
+#define CCU_PLL_OD_MAX \
+	((CCU_PLL_CTL_CLKOD_MASK >> CCU_PLL_CTL_CLKOD_FLD) + 1)
+#define CCU_PLL_NB_MAX \
+	((CCU_PLL_CTL1_BWADJ_MASK >> CCU_PLL_CTL1_BWADJ_FLD) + 1)
+#define CCU_PLL_FDIV_MIN		427000UL
+#define CCU_PLL_FDIV_MAX		3500000000UL
+#define CCU_PLL_FOUT_MIN		200000000UL
+#define CCU_PLL_FOUT_MAX		2500000000UL
+#define CCU_PLL_FVCO_MIN		700000000UL
+#define CCU_PLL_FVCO_MAX		3500000000UL
+#define CCU_PLL_CLKOD_FACTOR		2
+
+static inline unsigned long ccu_pll_lock_delay_us(unsigned long ref_clk,
+						  unsigned long nr)
+{
+	u64 us = 500ULL * nr * USEC_PER_SEC;
+
+	do_div(us, ref_clk);
+
+	return us;
+}
+
+static inline unsigned long ccu_pll_calc_freq(unsigned long ref_clk,
+					      unsigned long nr,
+					      unsigned long nf,
+					      unsigned long od)
+{
+	u64 tmp = ref_clk;
+
+	do_div(tmp, nr);
+	tmp *= nf;
+	do_div(tmp, od);
+
+	return tmp;
+}
+
+static int ccu_pll_reset(struct ccu_pll *pll, unsigned long ref_clk,
+			 unsigned long nr)
+{
+	unsigned long ud, ut;
+	u32 val;
+
+	ud = ccu_pll_lock_delay_us(ref_clk, nr);
+	ut = ud * CCU_PLL_LOCK_CHECK_RETRIES;
+
+	regmap_update_bits(pll->sys_regs, pll->reg_ctl,
+			   CCU_PLL_CTL_RST, CCU_PLL_CTL_RST);
+
+	return regmap_read_poll_timeout_atomic(pll->sys_regs, pll->reg_ctl, val,
+					       val & CCU_PLL_CTL_LOCK, ud, ut);
+}
+
+static int ccu_pll_enable(struct clk_hw *hw)
+{
+	struct clk_hw *parent_hw = clk_hw_get_parent(hw);
+	struct ccu_pll *pll = to_ccu_pll(hw);
+	unsigned long flags;
+	u32 val = 0;
+	int ret;
+
+	if (!parent_hw) {
+		pr_err("Can't enable '%s' with no parent", clk_hw_get_name(hw));
+		return -EINVAL;
+	}
+
+	regmap_read(pll->sys_regs, pll->reg_ctl, &val);
+	if (val & CCU_PLL_CTL_EN)
+		return 0;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	regmap_write(pll->sys_regs, pll->reg_ctl, val | CCU_PLL_CTL_EN);
+	ret = ccu_pll_reset(pll, clk_hw_get_rate(parent_hw),
+			    FIELD_GET(CCU_PLL_CTL_CLKR_MASK, val) + 1);
+	spin_unlock_irqrestore(&pll->lock, flags);
+	if (ret)
+		pr_err("PLL '%s' reset timed out\n", clk_hw_get_name(hw));
+
+	return ret;
+}
+
+static void ccu_pll_disable(struct clk_hw *hw)
+{
+	struct ccu_pll *pll = to_ccu_pll(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	regmap_update_bits(pll->sys_regs, pll->reg_ctl, CCU_PLL_CTL_EN, 0);
+	spin_unlock_irqrestore(&pll->lock, flags);
+}
+
+static int ccu_pll_is_enabled(struct clk_hw *hw)
+{
+	struct ccu_pll *pll = to_ccu_pll(hw);
+	u32 val = 0;
+
+	regmap_read(pll->sys_regs, pll->reg_ctl, &val);
+
+	return !!(val & CCU_PLL_CTL_EN);
+}
+
+static unsigned long ccu_pll_recalc_rate(struct clk_hw *hw,
+					 unsigned long parent_rate)
+{
+	struct ccu_pll *pll = to_ccu_pll(hw);
+	unsigned long nr, nf, od;
+	u32 val = 0;
+
+	regmap_read(pll->sys_regs, pll->reg_ctl, &val);
+	nr = FIELD_GET(CCU_PLL_CTL_CLKR_MASK, val) + 1;
+	nf = FIELD_GET(CCU_PLL_CTL_CLKF_MASK, val) + 1;
+	od = FIELD_GET(CCU_PLL_CTL_CLKOD_MASK, val) + 1;
+
+	return ccu_pll_calc_freq(parent_rate, nr, nf, od);
+}
+
+static void ccu_pll_calc_factors(unsigned long rate, unsigned long parent_rate,
+				 unsigned long *nr, unsigned long *nf,
+				 unsigned long *od)
+{
+	unsigned long err, freq, min_err = ULONG_MAX;
+	unsigned long num, denom, n1, d1, nri;
+	unsigned long nr_max, nf_max, od_max;
+
+	/*
+	 * Make sure PLL is working with valid input signal (Fdiv). If
+	 * you want to speed the function up just reduce CCU_PLL_NR_MAX.
+	 * This will cause a worse approximation though.
+	 */
+	nri = (parent_rate / CCU_PLL_FDIV_MAX) + 1;
+	nr_max = min(parent_rate / CCU_PLL_FDIV_MIN, CCU_PLL_NR_MAX);
+
+	/*
+	 * Find a closest [nr;nf;od] vector taking into account the
+	 * limitations like: 1) 700MHz <= Fvco <= 3.5GHz, 2) PLL Od is
+	 * either 1 or even number within the acceptable range (alas 1s
+	 * is also excluded by the next loop).
+	 */
+	for (; nri <= nr_max; ++nri) {
+		/* Use Od factor to fulfill the limitation 2). */
+		num = CCU_PLL_CLKOD_FACTOR * rate;
+		denom = parent_rate / nri;
+
+		/*
+		 * Make sure Fvco is within the acceptable range to fulfill
+		 * the condition 1). Note due to the CCU_PLL_CLKOD_FACTOR value
+		 * the actual upper limit is also divided by that factor.
+		 * It's not big problem for us since practically there is no
+		 * need in clocks with that high frequency.
+		 */
+		nf_max = min(CCU_PLL_FVCO_MAX / denom, CCU_PLL_NF_MAX);
+		od_max = CCU_PLL_OD_MAX / CCU_PLL_CLKOD_FACTOR;
+
+		/*
+		 * Bypass the out-of-bound values, which can't be properly
+		 * handled by the rational fraction approximation algorithm.
+		 */
+		if (num / denom >= nf_max) {
+			n1 = nf_max;
+			d1 = 1;
+		} else if (denom / num >= od_max) {
+			n1 = 1;
+			d1 = od_max;
+		} else {
+			rational_best_approximation(num, denom, nf_max, od_max,
+						    &n1, &d1);
+		}
+
+		/* Select the best approximation of the target rate. */
+		freq = ccu_pll_calc_freq(parent_rate, nri, n1, d1);
+		err = abs((int64_t)freq - num);
+		if (err < min_err) {
+			min_err = err;
+			*nr = nri;
+			*nf = n1;
+			*od = CCU_PLL_CLKOD_FACTOR * d1;
+		}
+	}
+}
+
+static long ccu_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long *parent_rate)
+{
+	unsigned long nr = 1, nf = 1, od = 1;
+
+	ccu_pll_calc_factors(rate, *parent_rate, &nr, &nf, &od);
+
+	return ccu_pll_calc_freq(*parent_rate, nr, nf, od);
+}
+
+/*
+ * This method is used for PLLs, which support the on-the-fly dividers
+ * adjustment. So there is no need in gating such clocks.
+ */
+static int ccu_pll_set_rate_reset(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct ccu_pll *pll = to_ccu_pll(hw);
+	unsigned long nr, nf, od;
+	unsigned long flags;
+	u32 mask, val;
+	int ret;
+
+	ccu_pll_calc_factors(rate, parent_rate, &nr, &nf, &od);
+
+	mask = CCU_PLL_CTL_CLKR_MASK | CCU_PLL_CTL_CLKF_MASK |
+	       CCU_PLL_CTL_CLKOD_MASK;
+	val = FIELD_PREP(CCU_PLL_CTL_CLKR_MASK, nr - 1) |
+	      FIELD_PREP(CCU_PLL_CTL_CLKF_MASK, nf - 1) |
+	      FIELD_PREP(CCU_PLL_CTL_CLKOD_MASK, od - 1);
+
+	spin_lock_irqsave(&pll->lock, flags);
+	regmap_update_bits(pll->sys_regs, pll->reg_ctl, mask, val);
+	ret = ccu_pll_reset(pll, parent_rate, nr);
+	spin_unlock_irqrestore(&pll->lock, flags);
+	if (ret)
+		pr_err("PLL '%s' reset timed out\n", clk_hw_get_name(hw));
+
+	return ret;
+}
+
+/*
+ * This method is used for PLLs, which don't support the on-the-fly dividers
+ * adjustment. So the corresponding clocks are supposed to be gated first.
+ */
+static int ccu_pll_set_rate_norst(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct ccu_pll *pll = to_ccu_pll(hw);
+	unsigned long nr, nf, od;
+	unsigned long flags;
+	u32 mask, val;
+
+	ccu_pll_calc_factors(rate, parent_rate, &nr, &nf, &od);
+
+	/*
+	 * Disable PLL if it was enabled by default or left enabled by the
+	 * system bootloader.
+	 */
+	mask = CCU_PLL_CTL_CLKR_MASK | CCU_PLL_CTL_CLKF_MASK |
+	       CCU_PLL_CTL_CLKOD_MASK | CCU_PLL_CTL_EN;
+	val = FIELD_PREP(CCU_PLL_CTL_CLKR_MASK, nr - 1) |
+	      FIELD_PREP(CCU_PLL_CTL_CLKF_MASK, nf - 1) |
+	      FIELD_PREP(CCU_PLL_CTL_CLKOD_MASK, od - 1);
+
+	spin_lock_irqsave(&pll->lock, flags);
+	regmap_update_bits(pll->sys_regs, pll->reg_ctl, mask, val);
+	spin_unlock_irqrestore(&pll->lock, flags);
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+struct ccu_pll_dbgfs_bit {
+	struct ccu_pll *pll;
+	const char *name;
+	unsigned int reg;
+	u32 mask;
+};
+
+struct ccu_pll_dbgfs_fld {
+	struct ccu_pll *pll;
+	const char *name;
+	unsigned int reg;
+	unsigned int lsb;
+	u32 mask;
+	u32 min;
+	u32 max;
+};
+
+#define CCU_PLL_DBGFS_BIT_ATTR(_name, _reg, _mask)	\
+	{						\
+		.name = _name,				\
+		.reg = _reg,				\
+		.mask = _mask				\
+	}
+
+#define CCU_PLL_DBGFS_FLD_ATTR(_name, _reg, _lsb, _mask, _min, _max)	\
+	{								\
+		.name = _name,						\
+		.reg = _reg,						\
+		.lsb = _lsb,						\
+		.mask = _mask,						\
+		.min = _min,						\
+		.max = _max						\
+	}
+
+static const struct ccu_pll_dbgfs_bit ccu_pll_bits[] = {
+	CCU_PLL_DBGFS_BIT_ATTR("pll_en", CCU_PLL_CTL, CCU_PLL_CTL_EN),
+	CCU_PLL_DBGFS_BIT_ATTR("pll_rst", CCU_PLL_CTL, CCU_PLL_CTL_RST),
+	CCU_PLL_DBGFS_BIT_ATTR("pll_bypass", CCU_PLL_CTL, CCU_PLL_CTL_BYPASS),
+	CCU_PLL_DBGFS_BIT_ATTR("pll_lock", CCU_PLL_CTL, CCU_PLL_CTL_LOCK)
+};
+
+#define CCU_PLL_DBGFS_BIT_NUM	ARRAY_SIZE(ccu_pll_bits)
+
+static const struct ccu_pll_dbgfs_fld ccu_pll_flds[] = {
+	CCU_PLL_DBGFS_FLD_ATTR("pll_nr", CCU_PLL_CTL, CCU_PLL_CTL_CLKR_FLD,
+				CCU_PLL_CTL_CLKR_MASK, 1, CCU_PLL_NR_MAX),
+	CCU_PLL_DBGFS_FLD_ATTR("pll_nf", CCU_PLL_CTL, CCU_PLL_CTL_CLKF_FLD,
+				CCU_PLL_CTL_CLKF_MASK, 1, CCU_PLL_NF_MAX),
+	CCU_PLL_DBGFS_FLD_ATTR("pll_od", CCU_PLL_CTL, CCU_PLL_CTL_CLKOD_FLD,
+				CCU_PLL_CTL_CLKOD_MASK, 1, CCU_PLL_OD_MAX),
+	CCU_PLL_DBGFS_FLD_ATTR("pll_nb", CCU_PLL_CTL1, CCU_PLL_CTL1_BWADJ_FLD,
+				CCU_PLL_CTL1_BWADJ_MASK, 1, CCU_PLL_NB_MAX)
+};
+
+#define CCU_PLL_DBGFS_FLD_NUM	ARRAY_SIZE(ccu_pll_flds)
+
+/*
+ * It can be dangerous to change the PLL settings behind clock framework back,
+ * therefore we don't provide any kernel config based compile time option for
+ * this feature to enable.
+ */
+#undef CCU_PLL_ALLOW_WRITE_DEBUGFS
+#ifdef CCU_PLL_ALLOW_WRITE_DEBUGFS
+
+static int ccu_pll_dbgfs_bit_set(void *priv, u64 val)
+{
+	const struct ccu_pll_dbgfs_bit *bit = priv;
+	struct ccu_pll *pll = bit->pll;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	regmap_update_bits(pll->sys_regs, pll->reg_ctl + bit->reg,
+			   bit->mask, val ? bit->mask : 0);
+	spin_unlock_irqrestore(&pll->lock, flags);
+
+	return 0;
+}
+
+static int ccu_pll_dbgfs_fld_set(void *priv, u64 val)
+{
+	struct ccu_pll_dbgfs_fld *fld = priv;
+	struct ccu_pll *pll = fld->pll;
+	unsigned long flags;
+	u32 data;
+
+	val = clamp_t(u64, val, fld->min, fld->max);
+	data = ((val - 1) << fld->lsb) & fld->mask;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	regmap_update_bits(pll->sys_regs, pll->reg_ctl + fld->reg, fld->mask,
+			   data);
+	spin_unlock_irqrestore(&pll->lock, flags);
+
+	return 0;
+}
+
+#define ccu_pll_dbgfs_mode	0644
+
+#else /* !CCU_PLL_ALLOW_WRITE_DEBUGFS */
+
+#define ccu_pll_dbgfs_bit_set	NULL
+#define ccu_pll_dbgfs_fld_set	NULL
+#define ccu_pll_dbgfs_mode	0444
+
+#endif /* !CCU_PLL_ALLOW_WRITE_DEBUGFS */
+
+static int ccu_pll_dbgfs_bit_get(void *priv, u64 *val)
+{
+	struct ccu_pll_dbgfs_bit *bit = priv;
+	struct ccu_pll *pll = bit->pll;
+	u32 data = 0;
+
+	regmap_read(pll->sys_regs, pll->reg_ctl + bit->reg, &data);
+	*val = !!(data & bit->mask);
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_pll_dbgfs_bit_fops,
+	ccu_pll_dbgfs_bit_get, ccu_pll_dbgfs_bit_set, "%llu\n");
+
+static int ccu_pll_dbgfs_fld_get(void *priv, u64 *val)
+{
+	struct ccu_pll_dbgfs_fld *fld = priv;
+	struct ccu_pll *pll = fld->pll;
+	u32 data = 0;
+
+	regmap_read(pll->sys_regs, pll->reg_ctl + fld->reg, &data);
+	*val = ((data & fld->mask) >> fld->lsb) + 1;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_pll_dbgfs_fld_fops,
+	ccu_pll_dbgfs_fld_get, ccu_pll_dbgfs_fld_set, "%llu\n");
+
+static void ccu_pll_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct ccu_pll *pll = to_ccu_pll(hw);
+	struct ccu_pll_dbgfs_bit *bits;
+	struct ccu_pll_dbgfs_fld *flds;
+	int idx;
+
+	bits = kcalloc(CCU_PLL_DBGFS_BIT_NUM, sizeof(*bits), GFP_KERNEL);
+	if (!bits)
+		return;
+
+	for (idx = 0; idx < CCU_PLL_DBGFS_BIT_NUM; ++idx) {
+		bits[idx] = ccu_pll_bits[idx];
+		bits[idx].pll = pll;
+
+		debugfs_create_file_unsafe(bits[idx].name, ccu_pll_dbgfs_mode,
+					   dentry, &bits[idx],
+					   &ccu_pll_dbgfs_bit_fops);
+	}
+
+	flds = kcalloc(CCU_PLL_DBGFS_FLD_NUM, sizeof(*flds), GFP_KERNEL);
+	if (!flds)
+		return;
+
+	for (idx = 0; idx < CCU_PLL_DBGFS_FLD_NUM; ++idx) {
+		flds[idx] = ccu_pll_flds[idx];
+		flds[idx].pll = pll;
+
+		debugfs_create_file_unsafe(flds[idx].name, ccu_pll_dbgfs_mode,
+					   dentry, &flds[idx],
+					   &ccu_pll_dbgfs_fld_fops);
+	}
+}
+
+#else /* !CONFIG_DEBUG_FS */
+
+#define ccu_pll_debug_init NULL
+
+#endif /* !CONFIG_DEBUG_FS */
+
+static const struct clk_ops ccu_pll_gate_to_set_ops = {
+	.enable = ccu_pll_enable,
+	.disable = ccu_pll_disable,
+	.is_enabled = ccu_pll_is_enabled,
+	.recalc_rate = ccu_pll_recalc_rate,
+	.round_rate = ccu_pll_round_rate,
+	.set_rate = ccu_pll_set_rate_norst,
+	.debug_init = ccu_pll_debug_init
+};
+
+static const struct clk_ops ccu_pll_straight_set_ops = {
+	.enable = ccu_pll_enable,
+	.disable = ccu_pll_disable,
+	.is_enabled = ccu_pll_is_enabled,
+	.recalc_rate = ccu_pll_recalc_rate,
+	.round_rate = ccu_pll_round_rate,
+	.set_rate = ccu_pll_set_rate_reset,
+	.debug_init = ccu_pll_debug_init
+};
+
+struct ccu_pll *ccu_pll_hw_register(const struct ccu_pll_init_data *pll_init)
+{
+	struct clk_parent_data parent_data = {0};
+	struct clk_init_data hw_init = {0};
+	struct ccu_pll *pll;
+	int ret;
+
+	if (!pll_init)
+		return ERR_PTR(-EINVAL);
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * Note since Baikal-T1 System Controller registers are MMIO-backed
+	 * we won't check the regmap IO operations return status, because it
+	 * must be zero anyway.
+	 */
+	pll->hw.init = &hw_init;
+	pll->reg_ctl = pll_init->base + CCU_PLL_CTL;
+	pll->reg_ctl1 = pll_init->base + CCU_PLL_CTL1;
+	pll->sys_regs = pll_init->sys_regs;
+	pll->id = pll_init->id;
+	spin_lock_init(&pll->lock);
+
+	hw_init.name = pll_init->name;
+	hw_init.flags = pll_init->flags;
+
+	if (hw_init.flags & CLK_SET_RATE_GATE)
+		hw_init.ops = &ccu_pll_gate_to_set_ops;
+	else
+		hw_init.ops = &ccu_pll_straight_set_ops;
+
+	if (!pll_init->parent_name) {
+		ret = -EINVAL;
+		goto err_free_pll;
+	}
+	parent_data.fw_name = pll_init->parent_name;
+	hw_init.parent_data = &parent_data;
+	hw_init.num_parents = 1;
+
+	ret = of_clk_hw_register(pll_init->np, &pll->hw);
+	if (ret)
+		goto err_free_pll;
+
+	return pll;
+
+err_free_pll:
+	kfree(pll);
+
+	return ERR_PTR(ret);
+}
+
+void ccu_pll_hw_unregister(struct ccu_pll *pll)
+{
+	clk_hw_unregister(&pll->hw);
+
+	kfree(pll);
+}
diff --git a/drivers/clk/baikal-t1/ccu-pll.h b/drivers/clk/baikal-t1/ccu-pll.h
new file mode 100644
index 000000000000..76cd9132a219
--- /dev/null
+++ b/drivers/clk/baikal-t1/ccu-pll.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Baikal-T1 CCU PLL interface driver
+ */
+#ifndef __CLK_BT1_CCU_PLL_H__
+#define __CLK_BT1_CCU_PLL_H__
+
+#include <linux/clk-provider.h>
+#include <linux/spinlock.h>
+#include <linux/regmap.h>
+#include <linux/bits.h>
+#include <linux/of.h>
+
+/*
+ * struct ccu_pll_init_data - CCU PLL initialization data
+ * @id: Clock private identifier.
+ * @name: Clocks name.
+ * @parent_name: Clocks parent name in a fw node.
+ * @base: PLL registers base address with respect to the sys_regs base.
+ * @sys_regs: Baikal-T1 System Controller registers map.
+ * @np: Pointer to the node describing the CCU PLLs.
+ * @flags: PLL clock flags.
+ */
+struct ccu_pll_init_data {
+	unsigned int id;
+	const char *name;
+	const char *parent_name;
+	unsigned int base;
+	struct regmap *sys_regs;
+	struct device_node *np;
+	unsigned long flags;
+};
+
+/*
+ * struct ccu_pll - CCU PLL descriptor
+ * @hw: clk_hw of the PLL.
+ * @id: Clock private identifier.
+ * @reg_ctl: PLL control register base.
+ * @reg_ctl1: PLL control1 register base.
+ * @sys_regs: Baikal-T1 System Controller registers map.
+ * @lock: PLL state change spin-lock.
+ */
+struct ccu_pll {
+	struct clk_hw hw;
+	unsigned int id;
+	unsigned int reg_ctl;
+	unsigned int reg_ctl1;
+	struct regmap *sys_regs;
+	spinlock_t lock;
+};
+#define to_ccu_pll(_hw) container_of(_hw, struct ccu_pll, hw)
+
+static inline struct clk_hw *ccu_pll_get_clk_hw(struct ccu_pll *pll)
+{
+	return pll ? &pll->hw : NULL;
+}
+
+struct ccu_pll *ccu_pll_hw_register(const struct ccu_pll_init_data *init);
+
+void ccu_pll_hw_unregister(struct ccu_pll *pll);
+
+#endif /* __CLK_BT1_CCU_PLL_H__ */
diff --git a/drivers/clk/baikal-t1/clk-ccu-pll.c b/drivers/clk/baikal-t1/clk-ccu-pll.c
new file mode 100644
index 000000000000..1eec8c0b8f50
--- /dev/null
+++ b/drivers/clk/baikal-t1/clk-ccu-pll.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Authors:
+ *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
+ *   Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
+ *
+ * Baikal-T1 CCU PLL clocks driver
+ */
+
+#define pr_fmt(fmt) "bt1-ccu-pll: " fmt
+
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/ioport.h>
+#include <linux/regmap.h>
+
+#include <dt-bindings/clock/bt1-ccu.h>
+
+#include "ccu-pll.h"
+
+#define CCU_CPU_PLL_BASE		0x000
+#define CCU_SATA_PLL_BASE		0x008
+#define CCU_DDR_PLL_BASE		0x010
+#define CCU_PCIE_PLL_BASE		0x018
+#define CCU_ETH_PLL_BASE		0x020
+
+#define CCU_PLL_INFO(_id, _name, _pname, _base, _flags)	\
+	{						\
+		.id = _id,				\
+		.name = _name,				\
+		.parent_name = _pname,			\
+		.base = _base,				\
+		.flags = _flags				\
+	}
+
+#define CCU_PLL_NUM			ARRAY_SIZE(pll_info)
+
+struct ccu_pll_info {
+	unsigned int id;
+	const char *name;
+	const char *parent_name;
+	unsigned int base;
+	unsigned long flags;
+};
+
+/*
+ * Mark as critical all PLLs except Ethernet one. CPU and DDR PLLs are sources
+ * of CPU cores and DDR controller reference clocks, due to which they
+ * obviously shouldn't be ever gated. SATA and PCIe PLLs are the parents of
+ * APB-bus and DDR controller AXI-bus clocks. If they are gated the system will
+ * be unusable.
+ */
+static const struct ccu_pll_info pll_info[] = {
+	CCU_PLL_INFO(CCU_CPU_PLL, "cpu_pll", "ref_clk", CCU_CPU_PLL_BASE,
+		     CLK_IS_CRITICAL),
+	CCU_PLL_INFO(CCU_SATA_PLL, "sata_pll", "ref_clk", CCU_SATA_PLL_BASE,
+		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE),
+	CCU_PLL_INFO(CCU_DDR_PLL, "ddr_pll", "ref_clk", CCU_DDR_PLL_BASE,
+		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE),
+	CCU_PLL_INFO(CCU_PCIE_PLL, "pcie_pll", "ref_clk", CCU_PCIE_PLL_BASE,
+		     CLK_IS_CRITICAL),
+	CCU_PLL_INFO(CCU_ETH_PLL, "eth_pll", "ref_clk", CCU_ETH_PLL_BASE,
+		     CLK_SET_RATE_GATE)
+};
+
+struct ccu_pll_data {
+	struct device_node *np;
+	struct regmap *sys_regs;
+	struct ccu_pll *plls[CCU_PLL_NUM];
+};
+
+static struct ccu_pll *ccu_pll_find_desc(struct ccu_pll_data *data,
+					 unsigned int clk_id)
+{
+	struct ccu_pll *pll;
+	int idx;
+
+	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
+		pll = data->plls[idx];
+		if (pll && pll->id == clk_id)
+			return pll;
+	}
+
+	return ERR_PTR(-EINVAL);
+}
+
+static struct ccu_pll_data *ccu_pll_create_data(struct device_node *np)
+{
+	struct ccu_pll_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	data->np = np;
+
+	return data;
+}
+
+static void ccu_pll_free_data(struct ccu_pll_data *data)
+{
+	kfree(data);
+}
+
+static int ccu_pll_find_sys_regs(struct ccu_pll_data *data)
+{
+	data->sys_regs = syscon_node_to_regmap(data->np->parent);
+	if (IS_ERR(data->sys_regs)) {
+		pr_err("Failed to find syscon regs for '%s'\n",
+			of_node_full_name(data->np));
+		return PTR_ERR(data->sys_regs);
+	}
+
+	return 0;
+}
+
+static struct clk_hw *ccu_pll_of_clk_hw_get(struct of_phandle_args *clkspec,
+					    void *priv)
+{
+	struct ccu_pll_data *data = priv;
+	struct ccu_pll *pll;
+	unsigned int clk_id;
+
+	clk_id = clkspec->args[0];
+	pll = ccu_pll_find_desc(data, clk_id);
+	if (IS_ERR(pll)) {
+		pr_info("Invalid PLL clock ID %d specified\n", clk_id);
+		return ERR_CAST(pll);
+	}
+
+	return ccu_pll_get_clk_hw(pll);
+}
+
+static int ccu_pll_clk_register(struct ccu_pll_data *data)
+{
+	int idx, ret;
+
+	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
+		const struct ccu_pll_info *info = &pll_info[idx];
+		struct ccu_pll_init_data init = {0};
+
+		init.id = info->id;
+		init.name = info->name;
+		init.parent_name = info->parent_name;
+		init.base = info->base;
+		init.sys_regs = data->sys_regs;
+		init.np = data->np;
+		init.flags = info->flags;
+
+		data->plls[idx] = ccu_pll_hw_register(&init);
+		if (IS_ERR(data->plls[idx])) {
+			ret = PTR_ERR(data->plls[idx]);
+			pr_err("Couldn't register PLL hw '%s'\n",
+				init.name);
+			goto err_hw_unregister;
+		}
+	}
+
+	ret = of_clk_add_hw_provider(data->np, ccu_pll_of_clk_hw_get, data);
+	if (ret) {
+		pr_err("Couldn't register PLL provider of '%s'\n",
+			of_node_full_name(data->np));
+		goto err_hw_unregister;
+	}
+
+	return 0;
+
+err_hw_unregister:
+	for (--idx; idx >= 0; --idx)
+		ccu_pll_hw_unregister(data->plls[idx]);
+
+	return ret;
+}
+
+static __init void ccu_pll_init(struct device_node *np)
+{
+	struct ccu_pll_data *data;
+	int ret;
+
+	data = ccu_pll_create_data(np);
+	if (IS_ERR(data))
+		return;
+
+	ret = ccu_pll_find_sys_regs(data);
+	if (ret)
+		goto err_free_data;
+
+	ret = ccu_pll_clk_register(data);
+	if (ret)
+		goto err_free_data;
+
+	return;
+
+err_free_data:
+	ccu_pll_free_data(data);
+}
+CLK_OF_DECLARE(ccu_pll, "baikal,bt1-ccu-pll", ccu_pll_init);
-- 
2.26.2


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v3 4/4] clk: Add Baikal-T1 CCU Dividers driver
  2020-05-26 22:20 [PATCH v3 0/4] clk: Add Baikal-T1 SoC Clock Control Unit support Serge Semin
                   ` (2 preceding siblings ...)
  2020-05-26 22:20 ` [PATCH v3 3/4] clk: Add Baikal-T1 CCU PLLs driver Serge Semin
@ 2020-05-26 22:20 ` Serge Semin
  2020-05-30 18:14   ` Stephen Boyd
  3 siblings, 1 reply; 11+ messages in thread
From: Serge Semin @ 2020-05-26 22:20 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Stephen Boyd, Michael Turquette
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	Rob Herring, linux-mips, devicetree, linux-kernel, linux-clk

Nearly each Baikal-T1 IP-core is supposed to have a clock source
of particular frequency. But since there are greater than five
IP-blocks embedded into the SoC, the CCU PLLs can't fulfill all the
needs. Baikal-T1 CCU provides a set of fixed and configurable clock
dividers in order to generate a necessary signal for each chip
sub-block.

This driver creates the of-based hardware clocks for each divider
available in Baikal-T1 CCU. The same way as for PLLs we split the
functionality up into the clocks operations (gate, ungate, set rate,
etc) and hardware clocks declaration/registration procedures.

In accordance with the CCU documentation all its dividers are distributed
into two CCU sub-blocks: AXI-bus and system devices reference clocks.
The former sub-block is used to supply the clocks for AXI-bus interfaces
(AXI clock domains) and the later one provides the SoC IP-cores reference
clocks. Each sub-block is represented by a dedicated DT node, so they
have different compatible strings to distinguish one from another.

For some reason CCU provides the dividers of different types. Some
dividers can be gateable some can't, some are fixed while the others
are variable, some have special divider' limitations, some've got a
non-standard register layout and so on. In order to cover all of these
cases the hardware clocks driver is designed with an info-descriptor
pattern. So there are special static descriptors declared for the
dividers of each type with additional flags describing the block
peculiarity. These descriptors are then used to create hardware clocks
with proper operations.

Some CCU dividers provide a way to reset a domain they generate
a clock for. So the CCU AXI-bus and CCU system devices clock
drivers also perform the reset controller registration.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org

---

Changelog v2:
- Rearrange the SoBs.
- Alter the commit message, since CCU isn't considered as MFD anymore.
- Enable the CCU Divider clock driver by default only if MIPS_BAIKAL_T1
  config.
- Fix spelling in the CCU Dividers kernel config description.
- Replace lock delay and frequency calculation macros with inline functions.
- Replace the data field setter and getter macro with handwritten inliners.
  Alas FIELD_{GET,PREP} can't be used here due to non-constant mask.
- Discard CLK_IGNORE_UNUSED flag setting. It's redundant since CLK_IS_CRITICAL
  is enough for cases when it's appropriate.
- Don't declare private copies of the Common Clock flags. Driver specific flags
  I renamed to "features".
- Comment out the CLK_IS_CRITICAL flag settings.
- Discard !div test in ccu_div_hw_unregister() method.
- Discard ccu_div_get_clk_id() method. Use not-null check instead of FFs-based
  invalid ID value.
- Discard alive probe message.
- Remove "clock-output-names" property support.
- Convert the driver to using syscon regmap instead of direct IO methods,
  since now the PLLs DT node is supposed to be a sub-node of the Baikal-T1
  System Controller node.
- Add DebugFS nodes in RO-mode by default.
---
 drivers/clk/baikal-t1/Kconfig       |  12 +
 drivers/clk/baikal-t1/Makefile      |   1 +
 drivers/clk/baikal-t1/ccu-div.c     | 602 ++++++++++++++++++++++++++++
 drivers/clk/baikal-t1/ccu-div.h     | 110 +++++
 drivers/clk/baikal-t1/clk-ccu-div.c | 487 ++++++++++++++++++++++
 5 files changed, 1212 insertions(+)
 create mode 100644 drivers/clk/baikal-t1/ccu-div.c
 create mode 100644 drivers/clk/baikal-t1/ccu-div.h
 create mode 100644 drivers/clk/baikal-t1/clk-ccu-div.c

diff --git a/drivers/clk/baikal-t1/Kconfig b/drivers/clk/baikal-t1/Kconfig
index 00398ee916dc..03102f1094bc 100644
--- a/drivers/clk/baikal-t1/Kconfig
+++ b/drivers/clk/baikal-t1/Kconfig
@@ -27,4 +27,16 @@ config CLK_BT1_CCU_PLL
 	  CPUs, DDR, etc.) or passed over the clock dividers to be only
 	  then used as an individual reference clock of a target device.
 
+config CLK_BT1_CCU_DIV
+	bool "Baikal-T1 CCU Dividers support"
+	select RESET_CONTROLLER
+	select MFD_SYSCON
+	default MIPS_BAIKAL_T1
+	help
+	  Enable this to support the CCU dividers used to distribute clocks
+	  between AXI-bus and system devices coming from CCU PLLs of Baikal-T1
+	  SoC. CCU dividers can be either configurable or with fixed divider,
+	  either gateable or ungateable. Some of the CCU dividers can be as well
+	  used to reset the domains they're supplying clock to.
+
 endif
diff --git a/drivers/clk/baikal-t1/Makefile b/drivers/clk/baikal-t1/Makefile
index 4a612bbacc37..b3b9590b95ed 100644
--- a/drivers/clk/baikal-t1/Makefile
+++ b/drivers/clk/baikal-t1/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_CLK_BT1_CCU_PLL) += ccu-pll.o clk-ccu-pll.o
+obj-$(CONFIG_CLK_BT1_CCU_DIV) += ccu-div.o clk-ccu-div.o
diff --git a/drivers/clk/baikal-t1/ccu-div.c b/drivers/clk/baikal-t1/ccu-div.c
new file mode 100644
index 000000000000..26aae8eec5ec
--- /dev/null
+++ b/drivers/clk/baikal-t1/ccu-div.c
@@ -0,0 +1,602 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Authors:
+ *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
+ *   Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
+ *
+ * Baikal-T1 CCU Dividers interface driver
+ */
+
+#define pr_fmt(fmt) "bt1-ccu-div: " fmt
+
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include <linux/regmap.h>
+#include <linux/delay.h>
+#include <linux/time64.h>
+#include <linux/debugfs.h>
+
+#include "ccu-div.h"
+
+#define CCU_DIV_CTL			0x00
+#define CCU_DIV_CTL_EN			BIT(0)
+#define CCU_DIV_CTL_RST			BIT(1)
+#define CCU_DIV_CTL_SET_CLKDIV		BIT(2)
+#define CCU_DIV_CTL_CLKDIV_FLD		4
+#define CCU_DIV_CTL_CLKDIV_MASK(_width) \
+	GENMASK((_width) + CCU_DIV_CTL_CLKDIV_FLD - 1, CCU_DIV_CTL_CLKDIV_FLD)
+#define CCU_DIV_CTL_LOCK_SHIFTED	BIT(27)
+#define CCU_DIV_CTL_LOCK_NORMAL		BIT(31)
+
+#define CCU_DIV_RST_DELAY_US		1
+#define CCU_DIV_LOCK_CHECK_RETRIES	50
+
+#define CCU_DIV_CLKDIV_MIN		0
+#define CCU_DIV_CLKDIV_MAX(_mask) \
+	((_mask) >> CCU_DIV_CTL_CLKDIV_FLD)
+
+/*
+ * Use the next two methods until there are generic field setter and
+ * getter available with non-constant mask support.
+ */
+static inline u32 ccu_div_get(u32 mask, u32 val)
+{
+	return (val & mask) >> CCU_DIV_CTL_CLKDIV_FLD;
+}
+
+static inline u32 ccu_div_prep(u32 mask, u32 val)
+{
+	return (val << CCU_DIV_CTL_CLKDIV_FLD) & mask;
+}
+
+static inline unsigned long ccu_div_lock_delay_ns(unsigned long ref_clk,
+						  unsigned long div)
+{
+	u64 ns = 4ULL * (div ?: 1) * NSEC_PER_SEC;
+
+	do_div(ns, ref_clk);
+
+	return ns;
+}
+
+static inline unsigned long ccu_div_calc_freq(unsigned long ref_clk,
+					      unsigned long div)
+{
+	return ref_clk / (div ?: 1);
+}
+
+static int ccu_div_var_update_clkdiv(struct ccu_div *div,
+				     unsigned long parent_rate,
+				     unsigned long divider)
+{
+	unsigned long nd;
+	u32 val = 0;
+	u32 lock;
+	int count;
+
+	nd = ccu_div_lock_delay_ns(parent_rate, divider);
+
+	if (div->features & CCU_DIV_LOCK_SHIFTED)
+		lock = CCU_DIV_CTL_LOCK_SHIFTED;
+	else
+		lock = CCU_DIV_CTL_LOCK_NORMAL;
+
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   CCU_DIV_CTL_SET_CLKDIV, CCU_DIV_CTL_SET_CLKDIV);
+
+	/*
+	 * Until there is nsec-version of readl_poll_timeout() is available
+	 * we have to implement the next polling loop.
+	 */
+	count = CCU_DIV_LOCK_CHECK_RETRIES;
+	do {
+		ndelay(nd);
+		regmap_read(div->sys_regs, div->reg_ctl, &val);
+		if (val & lock)
+			return 0;
+	} while (--count);
+
+	return -ETIMEDOUT;
+}
+
+static int ccu_div_var_enable(struct clk_hw *hw)
+{
+	struct clk_hw *parent_hw = clk_hw_get_parent(hw);
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags;
+	u32 val = 0;
+	int ret;
+
+	if (!parent_hw) {
+		pr_err("Can't enable '%s' with no parent", clk_hw_get_name(hw));
+		return -EINVAL;
+	}
+
+	regmap_read(div->sys_regs, div->reg_ctl, &val);
+	if (val & CCU_DIV_CTL_EN)
+		return 0;
+
+	spin_lock_irqsave(&div->lock, flags);
+	ret = ccu_div_var_update_clkdiv(div, clk_hw_get_rate(parent_hw),
+					ccu_div_get(div->mask, val));
+	if (!ret)
+		regmap_update_bits(div->sys_regs, div->reg_ctl,
+				   CCU_DIV_CTL_EN, CCU_DIV_CTL_EN);
+	spin_unlock_irqrestore(&div->lock, flags);
+	if (ret)
+		pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw));
+
+	return ret;
+}
+
+static int ccu_div_gate_enable(struct clk_hw *hw)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   CCU_DIV_CTL_EN, CCU_DIV_CTL_EN);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+static void ccu_div_gate_disable(struct clk_hw *hw)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl, CCU_DIV_CTL_EN, 0);
+	spin_unlock_irqrestore(&div->lock, flags);
+}
+
+static int ccu_div_gate_is_enabled(struct clk_hw *hw)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	u32 val = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &val);
+
+	return !!(val & CCU_DIV_CTL_EN);
+}
+
+static unsigned long ccu_div_var_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long divider;
+	u32 val = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &val);
+	divider = ccu_div_get(div->mask, val);
+
+	return ccu_div_calc_freq(parent_rate, divider);
+}
+
+static inline unsigned long ccu_div_var_calc_divider(unsigned long rate,
+						     unsigned long parent_rate,
+						     unsigned int mask)
+{
+	unsigned long divider;
+
+	divider = parent_rate / rate;
+	return clamp_t(unsigned long, divider, CCU_DIV_CLKDIV_MIN,
+		       CCU_DIV_CLKDIV_MAX(mask));
+}
+
+static long ccu_div_var_round_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long *parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long divider;
+
+	divider = ccu_div_var_calc_divider(rate, *parent_rate, div->mask);
+
+	return ccu_div_calc_freq(*parent_rate, divider);
+}
+
+/*
+ * This method is used for the clock divider blocks, which support the
+ * on-the-fly rate change. So due to lacking the EN bit functionality
+ * they can't be gated before the rate adjustment.
+ */
+static int ccu_div_var_set_rate_slow(struct clk_hw *hw, unsigned long rate,
+				     unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags, divider;
+	u32 val;
+	int ret;
+
+	divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask);
+	if (divider == 1 && div->features & CCU_DIV_SKIP_ONE) {
+		divider = 0;
+	} else if (div->features & CCU_DIV_SKIP_ONE_TO_THREE) {
+		if (divider == 1 || divider == 2)
+			divider = 0;
+		else if (divider == 3)
+			divider = 4;
+	}
+
+	val = ccu_div_prep(div->mask, divider);
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, val);
+	ret = ccu_div_var_update_clkdiv(div, parent_rate, divider);
+	spin_unlock_irqrestore(&div->lock, flags);
+	if (ret)
+		pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw));
+
+	return ret;
+}
+
+/*
+ * This method is used for the clock divider blocks, which don't support
+ * the on-the-fly rate change.
+ */
+static int ccu_div_var_set_rate_fast(struct clk_hw *hw, unsigned long rate,
+				     unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	unsigned long flags, divider = 1;
+	u32 val;
+
+	divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask);
+	val = ccu_div_prep(div->mask, divider);
+
+	/*
+	 * Also disable the clock divider block if it was enabled by default
+	 * or by the bootloader.
+	 */
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   div->mask | CCU_DIV_CTL_EN, val);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+static unsigned long ccu_div_fixed_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+
+	return ccu_div_calc_freq(parent_rate, div->divider);
+}
+
+static long ccu_div_fixed_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+
+	return ccu_div_calc_freq(*parent_rate, div->divider);
+}
+
+static int ccu_div_fixed_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	return 0;
+}
+
+int ccu_div_reset_domain(struct ccu_div *div)
+{
+	unsigned long flags;
+
+	if (!div || !(div->features & CCU_DIV_RESET_DOMAIN))
+		return -EINVAL;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   CCU_DIV_CTL_RST, CCU_DIV_CTL_RST);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	/* The next delay must be enough to cover all the resets. */
+	udelay(CCU_DIV_RST_DELAY_US);
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+struct ccu_div_dbgfs_bit {
+	struct ccu_div *div;
+	const char *name;
+	u32 mask;
+};
+
+#define CCU_DIV_DBGFS_BIT_ATTR(_name, _mask) {	\
+		.name = _name,			\
+		.mask = _mask			\
+	}
+
+static const struct ccu_div_dbgfs_bit ccu_div_bits[] = {
+	CCU_DIV_DBGFS_BIT_ATTR("div_en", CCU_DIV_CTL_EN),
+	CCU_DIV_DBGFS_BIT_ATTR("div_rst", CCU_DIV_CTL_RST),
+	CCU_DIV_DBGFS_BIT_ATTR("div_bypass", CCU_DIV_CTL_SET_CLKDIV),
+	CCU_DIV_DBGFS_BIT_ATTR("div_lock", CCU_DIV_CTL_LOCK_NORMAL)
+};
+
+#define CCU_DIV_DBGFS_BIT_NUM	ARRAY_SIZE(ccu_div_bits)
+
+/*
+ * It can be dangerous to change the Divider settings behind clock framework
+ * back, therefore we don't provide any kernel config based compile time option
+ * for this feature to enable.
+ */
+#undef CCU_DIV_ALLOW_WRITE_DEBUGFS
+#ifdef CCU_DIV_ALLOW_WRITE_DEBUGFS
+
+static int ccu_div_dbgfs_bit_set(void *priv, u64 val)
+{
+	const struct ccu_div_dbgfs_bit *bit = priv;
+	struct ccu_div *div = bit->div;
+	unsigned long flags;
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl,
+			   bit->mask, val ? bit->mask : 0);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+static int ccu_div_dbgfs_var_clkdiv_set(void *priv, u64 val)
+{
+	struct ccu_div *div = priv;
+	unsigned long flags;
+	u32 data;
+
+	val = clamp_t(u64, val, CCU_DIV_CLKDIV_MIN,
+		      CCU_DIV_CLKDIV_MAX(div->mask));
+	data = ccu_div_prep(div->mask, val);
+
+	spin_lock_irqsave(&div->lock, flags);
+	regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, data);
+	spin_unlock_irqrestore(&div->lock, flags);
+
+	return 0;
+}
+
+#define ccu_div_dbgfs_mode		0644
+
+#else /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */
+
+#define ccu_div_dbgfs_bit_set		NULL
+#define ccu_div_dbgfs_var_clkdiv_set	NULL
+#define ccu_div_dbgfs_mode		0444
+
+#endif /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */
+
+static int ccu_div_dbgfs_bit_get(void *priv, u64 *val)
+{
+	const struct ccu_div_dbgfs_bit *bit = priv;
+	struct ccu_div *div = bit->div;
+	u32 data = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &data);
+	*val = !!(data & bit->mask);
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_bit_fops,
+	ccu_div_dbgfs_bit_get, ccu_div_dbgfs_bit_set, "%llu\n");
+
+static int ccu_div_dbgfs_var_clkdiv_get(void *priv, u64 *val)
+{
+	struct ccu_div *div = priv;
+	u32 data = 0;
+
+	regmap_read(div->sys_regs, div->reg_ctl, &data);
+	*val = ccu_div_get(div->mask, data);
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_var_clkdiv_fops,
+	ccu_div_dbgfs_var_clkdiv_get, ccu_div_dbgfs_var_clkdiv_set, "%llu\n");
+
+static int ccu_div_dbgfs_fixed_clkdiv_get(void *priv, u64 *val)
+{
+	struct ccu_div *div = priv;
+
+	*val = div->divider;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_fixed_clkdiv_fops,
+	ccu_div_dbgfs_fixed_clkdiv_get, NULL, "%llu\n");
+
+static void ccu_div_var_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	struct ccu_div_dbgfs_bit *bits;
+	int didx, bidx, num = 2;
+	const char *name;
+
+	num += !!(div->flags & CLK_SET_RATE_GATE) +
+		!!(div->features & CCU_DIV_RESET_DOMAIN);
+
+	bits = kcalloc(num, sizeof(*bits), GFP_KERNEL);
+	if (!bits)
+		return;
+
+	for (didx = 0, bidx = 0; bidx < CCU_DIV_DBGFS_BIT_NUM; ++bidx) {
+		name = ccu_div_bits[bidx].name;
+		if (!(div->flags & CLK_SET_RATE_GATE) &&
+		    !strcmp("div_en", name)) {
+			continue;
+		}
+
+		if (!(div->features & CCU_DIV_RESET_DOMAIN) &&
+		    !strcmp("div_rst", name)) {
+			continue;
+		}
+
+		bits[didx] = ccu_div_bits[bidx];
+		bits[didx].div = div;
+
+		if (div->features & CCU_DIV_LOCK_SHIFTED &&
+		    !strcmp("div_lock", name)) {
+			bits[didx].mask = CCU_DIV_CTL_LOCK_SHIFTED;
+		}
+
+		debugfs_create_file_unsafe(bits[didx].name, ccu_div_dbgfs_mode,
+					   dentry, &bits[didx],
+					   &ccu_div_dbgfs_bit_fops);
+		++didx;
+	}
+
+	debugfs_create_file_unsafe("div_clkdiv", ccu_div_dbgfs_mode, dentry,
+				   div, &ccu_div_dbgfs_var_clkdiv_fops);
+}
+
+static void ccu_div_gate_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+	struct ccu_div_dbgfs_bit *bit;
+
+	bit = kmalloc(sizeof(*bit), GFP_KERNEL);
+	if (!bit)
+		return;
+
+	*bit = ccu_div_bits[0];
+	bit->div = div;
+	debugfs_create_file_unsafe(bit->name, ccu_div_dbgfs_mode, dentry, bit,
+				   &ccu_div_dbgfs_bit_fops);
+
+	debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div,
+				   &ccu_div_dbgfs_fixed_clkdiv_fops);
+}
+
+static void ccu_div_fixed_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	struct ccu_div *div = to_ccu_div(hw);
+
+	debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div,
+				   &ccu_div_dbgfs_fixed_clkdiv_fops);
+}
+
+#else /* !CONFIG_DEBUG_FS */
+
+#define ccu_div_var_debug_init NULL
+#define ccu_div_gate_debug_init NULL
+#define ccu_div_fixed_debug_init NULL
+
+#endif /* !CONFIG_DEBUG_FS */
+
+static const struct clk_ops ccu_div_var_gate_to_set_ops = {
+	.enable = ccu_div_var_enable,
+	.disable = ccu_div_gate_disable,
+	.is_enabled = ccu_div_gate_is_enabled,
+	.recalc_rate = ccu_div_var_recalc_rate,
+	.round_rate = ccu_div_var_round_rate,
+	.set_rate = ccu_div_var_set_rate_fast,
+	.debug_init = ccu_div_var_debug_init
+};
+
+static const struct clk_ops ccu_div_var_nogate_ops = {
+	.recalc_rate = ccu_div_var_recalc_rate,
+	.round_rate = ccu_div_var_round_rate,
+	.set_rate = ccu_div_var_set_rate_slow,
+	.debug_init = ccu_div_var_debug_init
+};
+
+static const struct clk_ops ccu_div_gate_ops = {
+	.enable = ccu_div_gate_enable,
+	.disable = ccu_div_gate_disable,
+	.is_enabled = ccu_div_gate_is_enabled,
+	.recalc_rate = ccu_div_fixed_recalc_rate,
+	.round_rate = ccu_div_fixed_round_rate,
+	.set_rate = ccu_div_fixed_set_rate,
+	.debug_init = ccu_div_gate_debug_init
+};
+
+static const struct clk_ops ccu_div_fixed_ops = {
+	.recalc_rate = ccu_div_fixed_recalc_rate,
+	.round_rate = ccu_div_fixed_round_rate,
+	.set_rate = ccu_div_fixed_set_rate,
+	.debug_init = ccu_div_fixed_debug_init
+};
+
+struct ccu_div *ccu_div_hw_register(const struct ccu_div_init_data *div_init)
+{
+	struct clk_parent_data parent_data = {0};
+	struct clk_init_data hw_init = {0};
+	struct ccu_div *div;
+	int ret;
+
+	if (!div_init)
+		return ERR_PTR(-EINVAL);
+
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * Note since Baikal-T1 System Controller registers are MMIO-backed
+	 * we won't check the regmap IO operations return status, because it
+	 * must be zero anyway.
+	 */
+	div->hw.init = &hw_init;
+	div->id = div_init->id;
+	div->reg_ctl = div_init->base + CCU_DIV_CTL;
+	div->sys_regs = div_init->sys_regs;
+	div->flags = div_init->flags;
+	div->features = div_init->features;
+	spin_lock_init(&div->lock);
+
+	hw_init.name = div_init->name;
+	hw_init.flags = div_init->flags;
+
+	if (div_init->type == CCU_DIV_VAR) {
+		if (hw_init.flags & CLK_SET_RATE_GATE)
+			hw_init.ops = &ccu_div_var_gate_to_set_ops;
+		else
+			hw_init.ops = &ccu_div_var_nogate_ops;
+		div->mask = CCU_DIV_CTL_CLKDIV_MASK(div_init->width);
+	} else if (div_init->type == CCU_DIV_GATE) {
+		hw_init.ops = &ccu_div_gate_ops;
+		div->divider = div_init->divider;
+	} else if (div_init->type == CCU_DIV_FIXED) {
+		hw_init.ops = &ccu_div_fixed_ops;
+		div->divider = div_init->divider;
+	} else {
+		ret = -EINVAL;
+		goto err_free_div;
+	}
+
+	if (!div_init->parent_name) {
+		ret = -EINVAL;
+		goto err_free_div;
+	}
+	parent_data.fw_name = div_init->parent_name;
+	hw_init.parent_data = &parent_data;
+	hw_init.num_parents = 1;
+
+	ret = of_clk_hw_register(div_init->np, &div->hw);
+	if (ret)
+		goto err_free_div;
+
+	return div;
+
+err_free_div:
+	kfree(div);
+
+	return ERR_PTR(ret);
+}
+
+void ccu_div_hw_unregister(struct ccu_div *div)
+{
+	clk_hw_unregister(&div->hw);
+
+	kfree(div);
+}
diff --git a/drivers/clk/baikal-t1/ccu-div.h b/drivers/clk/baikal-t1/ccu-div.h
new file mode 100644
index 000000000000..795665caefbd
--- /dev/null
+++ b/drivers/clk/baikal-t1/ccu-div.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Baikal-T1 CCU Dividers interface driver
+ */
+#ifndef __CLK_BT1_CCU_DIV_H__
+#define __CLK_BT1_CCU_DIV_H__
+
+#include <linux/clk-provider.h>
+#include <linux/spinlock.h>
+#include <linux/regmap.h>
+#include <linux/bits.h>
+#include <linux/of.h>
+
+/*
+ * CCU Divider private flags
+ * @CCU_DIV_SKIP_ONE: Due to some reason divider can't be set to 1.
+ *		      It can be 0 though, which is functionally the same.
+ * @CCU_DIV_SKIP_ONE_TO_THREE: For some reason divider can't be within [1,3].
+ *			       It can be either 0 or greater than 3.
+ * @CCU_DIV_LOCK_SHIFTED: Find lock-bit at non-standard position.
+ * @CCU_DIV_RESET_DOMAIN: Provide reset clock domain method.
+ */
+#define CCU_DIV_SKIP_ONE		BIT(1)
+#define CCU_DIV_SKIP_ONE_TO_THREE	BIT(2)
+#define CCU_DIV_LOCK_SHIFTED		BIT(3)
+#define CCU_DIV_RESET_DOMAIN		BIT(4)
+
+/*
+ * enum ccu_div_type - CCU Divider types
+ * @CCU_DIV_VAR: Clocks gate with variable divider.
+ * @CCU_DIV_GATE: Clocks gate with fixed divider.
+ * @CCU_DIV_FIXED: Ungateable clock with fixed divider.
+ */
+enum ccu_div_type {
+	CCU_DIV_VAR,
+	CCU_DIV_GATE,
+	CCU_DIV_FIXED
+};
+
+/*
+ * struct ccu_div_init_data - CCU Divider initialization data
+ * @id: Clocks private identifier.
+ * @name: Clocks name.
+ * @parent_name: Parent clocks name in a fw node.
+ * @base: Divider register base address with respect to the sys_regs base.
+ * @sys_regs: Baikal-T1 System Controller registers map.
+ * @np: Pointer to the node describing the CCU Dividers.
+ * @type: CCU divider type (variable, fixed with and without gate).
+ * @width: Divider width if it's variable.
+ * @divider: Divider fixed value.
+ * @flags: CCU Divider clock flags.
+ * @features: CCU Divider private features.
+ */
+struct ccu_div_init_data {
+	unsigned int id;
+	const char *name;
+	const char *parent_name;
+	unsigned int base;
+	struct regmap *sys_regs;
+	struct device_node *np;
+	enum ccu_div_type type;
+	union {
+		unsigned int width;
+		unsigned int divider;
+	};
+	unsigned long flags;
+	unsigned long features;
+};
+
+/*
+ * struct ccu_div - CCU Divider descriptor
+ * @hw: clk_hw of the divider.
+ * @id: Clock private identifier.
+ * @reg_ctl: Divider control register base address.
+ * @sys_regs: Baikal-T1 System Controller registers map.
+ * @lock: Divider state change spin-lock.
+ * @mask: Divider field mask.
+ * @divider: Divider fixed value.
+ * @flags: Divider clock flags.
+ * @features: CCU Divider private features.
+ */
+struct ccu_div {
+	struct clk_hw hw;
+	unsigned int id;
+	unsigned int reg_ctl;
+	struct regmap *sys_regs;
+	spinlock_t lock;
+	union {
+		u32 mask;
+		unsigned int divider;
+	};
+	unsigned long flags;
+	unsigned long features;
+};
+#define to_ccu_div(_hw) container_of(_hw, struct ccu_div, hw)
+
+static inline struct clk_hw *ccu_div_get_clk_hw(struct ccu_div *div)
+{
+	return div ? &div->hw : NULL;
+}
+
+struct ccu_div *ccu_div_hw_register(const struct ccu_div_init_data *init);
+
+void ccu_div_hw_unregister(struct ccu_div *div);
+
+int ccu_div_reset_domain(struct ccu_div *div);
+
+#endif /* __CLK_BT1_CCU_DIV_H__ */
diff --git a/drivers/clk/baikal-t1/clk-ccu-div.c b/drivers/clk/baikal-t1/clk-ccu-div.c
new file mode 100644
index 000000000000..3931a2d33943
--- /dev/null
+++ b/drivers/clk/baikal-t1/clk-ccu-div.c
@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Authors:
+ *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
+ *   Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
+ *
+ * Baikal-T1 CCU Dividers clock driver
+ */
+
+#define pr_fmt(fmt) "bt1-ccu-div: " fmt
+
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include <linux/reset-controller.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/ioport.h>
+#include <linux/regmap.h>
+
+#include <dt-bindings/clock/bt1-ccu.h>
+#include <dt-bindings/reset/bt1-ccu.h>
+
+#include "ccu-div.h"
+
+#define CCU_AXI_MAIN_BASE		0x030
+#define CCU_AXI_DDR_BASE		0x034
+#define CCU_AXI_SATA_BASE		0x038
+#define CCU_AXI_GMAC0_BASE		0x03C
+#define CCU_AXI_GMAC1_BASE		0x040
+#define CCU_AXI_XGMAC_BASE		0x044
+#define CCU_AXI_PCIE_M_BASE		0x048
+#define CCU_AXI_PCIE_S_BASE		0x04C
+#define CCU_AXI_USB_BASE		0x050
+#define CCU_AXI_HWA_BASE		0x054
+#define CCU_AXI_SRAM_BASE		0x058
+
+#define CCU_SYS_SATA_REF_BASE		0x060
+#define CCU_SYS_APB_BASE		0x064
+#define CCU_SYS_GMAC0_BASE		0x068
+#define CCU_SYS_GMAC1_BASE		0x06C
+#define CCU_SYS_XGMAC_BASE		0x070
+#define CCU_SYS_USB_BASE		0x074
+#define CCU_SYS_PVT_BASE		0x078
+#define CCU_SYS_HWA_BASE		0x07C
+#define CCU_SYS_UART_BASE		0x084
+#define CCU_SYS_TIMER0_BASE		0x088
+#define CCU_SYS_TIMER1_BASE		0x08C
+#define CCU_SYS_TIMER2_BASE		0x090
+#define CCU_SYS_WDT_BASE		0x150
+
+#define CCU_DIV_VAR_INFO(_id, _name, _pname, _base, _width, _flags, _features) \
+	{								\
+		.id = _id,						\
+		.name = _name,						\
+		.parent_name = _pname,					\
+		.base = _base,						\
+		.type = CCU_DIV_VAR,					\
+		.width = _width,					\
+		.flags = _flags,					\
+		.features = _features					\
+	}
+
+#define CCU_DIV_GATE_INFO(_id, _name, _pname, _base, _divider)	\
+	{							\
+		.id = _id,					\
+		.name = _name,					\
+		.parent_name = _pname,				\
+		.base = _base,					\
+		.type = CCU_DIV_GATE,				\
+		.divider = _divider				\
+	}
+
+#define CCU_DIV_FIXED_INFO(_id, _name, _pname, _divider)	\
+	{							\
+		.id = _id,					\
+		.name = _name,					\
+		.parent_name = _pname,				\
+		.type = CCU_DIV_FIXED,				\
+		.divider = _divider				\
+	}
+
+#define CCU_DIV_RST_MAP(_rst_id, _clk_id)	\
+	{					\
+		.rst_id = _rst_id,		\
+		.clk_id = _clk_id		\
+	}
+
+struct ccu_div_info {
+	unsigned int id;
+	const char *name;
+	const char *parent_name;
+	unsigned int base;
+	enum ccu_div_type type;
+	union {
+		unsigned int width;
+		unsigned int divider;
+	};
+	unsigned long flags;
+	unsigned long features;
+};
+
+struct ccu_div_rst_map {
+	unsigned int rst_id;
+	unsigned int clk_id;
+};
+
+struct ccu_div_data {
+	struct device_node *np;
+	struct regmap *sys_regs;
+
+	unsigned int divs_num;
+	const struct ccu_div_info *divs_info;
+	struct ccu_div **divs;
+
+	unsigned int rst_num;
+	const struct ccu_div_rst_map *rst_map;
+	struct reset_controller_dev rcdev;
+};
+#define to_ccu_div_data(_rcdev) container_of(_rcdev, struct ccu_div_data, rcdev)
+
+/*
+ * AXI Main Interconnect (axi_main_clk) and DDR AXI-bus (axi_ddr_clk) clocks
+ * must be left enabled in any case, since former one is responsible for
+ * clocking a bus between CPU cores and the rest of the SoC components, while
+ * the later is clocking the AXI-bus between DDR controller and the Main
+ * Interconnect. So should any of these clocks get to be disabled, the system
+ * will literally stop working. That's why we marked them as critical.
+ */
+static const struct ccu_div_info axi_info[] = {
+	CCU_DIV_VAR_INFO(CCU_AXI_MAIN_CLK, "axi_main_clk", "pcie_clk",
+			 CCU_AXI_MAIN_BASE, 4,
+			 CLK_IS_CRITICAL, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_DDR_CLK, "axi_ddr_clk", "sata_clk",
+			 CCU_AXI_DDR_BASE, 4,
+			 CLK_IS_CRITICAL | CLK_SET_RATE_GATE,
+			 CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_SATA_CLK, "axi_sata_clk", "sata_clk",
+			 CCU_AXI_SATA_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_GMAC0_CLK, "axi_gmac0_clk", "eth_clk",
+			 CCU_AXI_GMAC0_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_GMAC1_CLK, "axi_gmac1_clk", "eth_clk",
+			 CCU_AXI_GMAC1_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_XGMAC_CLK, "axi_xgmac_clk", "eth_clk",
+			 CCU_AXI_XGMAC_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_PCIE_M_CLK, "axi_pcie_m_clk", "pcie_clk",
+			 CCU_AXI_PCIE_M_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_PCIE_S_CLK, "axi_pcie_s_clk", "pcie_clk",
+			 CCU_AXI_PCIE_S_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_USB_CLK, "axi_usb_clk", "sata_clk",
+			 CCU_AXI_USB_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_HWA_CLK, "axi_hwa_clk", "sata_clk",
+			 CCU_AXI_HWA_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_AXI_SRAM_CLK, "axi_sram_clk", "eth_clk",
+			 CCU_AXI_SRAM_BASE, 4,
+			 CLK_SET_RATE_GATE, CCU_DIV_RESET_DOMAIN)
+};
+
+static const struct ccu_div_rst_map axi_rst_map[] = {
+	CCU_DIV_RST_MAP(CCU_AXI_MAIN_RST, CCU_AXI_MAIN_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_DDR_RST, CCU_AXI_DDR_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_SATA_RST, CCU_AXI_SATA_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_GMAC0_RST, CCU_AXI_GMAC0_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_GMAC1_RST, CCU_AXI_GMAC1_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_XGMAC_RST, CCU_AXI_XGMAC_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_PCIE_M_RST, CCU_AXI_PCIE_M_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_PCIE_S_RST, CCU_AXI_PCIE_S_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_USB_RST, CCU_AXI_USB_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_HWA_RST, CCU_AXI_HWA_CLK),
+	CCU_DIV_RST_MAP(CCU_AXI_SRAM_RST, CCU_AXI_SRAM_CLK)
+};
+
+/*
+ * APB-bus clock is marked as critical since it's a main communication bus
+ * for the SoC devices registers IO-operations.
+ */
+static const struct ccu_div_info sys_info[] = {
+	CCU_DIV_VAR_INFO(CCU_SYS_SATA_REF_CLK, "sys_sata_ref_clk",
+			 "sata_clk", CCU_SYS_SATA_REF_BASE, 4,
+			 CLK_SET_RATE_GATE,
+			 CCU_DIV_SKIP_ONE | CCU_DIV_LOCK_SHIFTED |
+			 CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_VAR_INFO(CCU_SYS_APB_CLK, "sys_apb_clk",
+			 "pcie_clk", CCU_SYS_APB_BASE, 5,
+			 CLK_IS_CRITICAL, CCU_DIV_RESET_DOMAIN),
+	CCU_DIV_GATE_INFO(CCU_SYS_GMAC0_TX_CLK, "sys_gmac0_tx_clk",
+			  "eth_clk", CCU_SYS_GMAC0_BASE, 5),
+	CCU_DIV_FIXED_INFO(CCU_SYS_GMAC0_PTP_CLK, "sys_gmac0_ptp_clk",
+			   "eth_clk", 10),
+	CCU_DIV_GATE_INFO(CCU_SYS_GMAC1_TX_CLK, "sys_gmac1_tx_clk",
+			  "eth_clk", CCU_SYS_GMAC1_BASE, 5),
+	CCU_DIV_FIXED_INFO(CCU_SYS_GMAC1_PTP_CLK, "sys_gmac1_ptp_clk",
+			   "eth_clk", 10),
+	CCU_DIV_GATE_INFO(CCU_SYS_XGMAC_REF_CLK, "sys_xgmac_ref_clk",
+			  "eth_clk", CCU_SYS_XGMAC_BASE, 8),
+	CCU_DIV_FIXED_INFO(CCU_SYS_XGMAC_PTP_CLK, "sys_xgmac_ptp_clk",
+			   "eth_clk", 10),
+	CCU_DIV_GATE_INFO(CCU_SYS_USB_CLK, "sys_usb_clk",
+			  "eth_clk", CCU_SYS_USB_BASE, 10),
+	CCU_DIV_VAR_INFO(CCU_SYS_PVT_CLK, "sys_pvt_clk",
+			 "ref_clk", CCU_SYS_PVT_BASE, 5,
+			 CLK_SET_RATE_GATE, 0),
+	CCU_DIV_VAR_INFO(CCU_SYS_HWA_CLK, "sys_hwa_clk",
+			 "sata_clk", CCU_SYS_HWA_BASE, 4,
+			 CLK_SET_RATE_GATE, 0),
+	CCU_DIV_VAR_INFO(CCU_SYS_UART_CLK, "sys_uart_clk",
+			 "eth_clk", CCU_SYS_UART_BASE, 17,
+			 CLK_SET_RATE_GATE, 0),
+	CCU_DIV_FIXED_INFO(CCU_SYS_I2C1_CLK, "sys_i2c1_clk",
+			   "eth_clk", 10),
+	CCU_DIV_FIXED_INFO(CCU_SYS_I2C2_CLK, "sys_i2c2_clk",
+			   "eth_clk", 10),
+	CCU_DIV_FIXED_INFO(CCU_SYS_GPIO_CLK, "sys_gpio_clk",
+			   "ref_clk", 25),
+	CCU_DIV_VAR_INFO(CCU_SYS_TIMER0_CLK, "sys_timer0_clk",
+			 "ref_clk", CCU_SYS_TIMER0_BASE, 17,
+			 CLK_SET_RATE_GATE, 0),
+	CCU_DIV_VAR_INFO(CCU_SYS_TIMER1_CLK, "sys_timer1_clk",
+			 "ref_clk", CCU_SYS_TIMER1_BASE, 17,
+			 CLK_SET_RATE_GATE, 0),
+	CCU_DIV_VAR_INFO(CCU_SYS_TIMER2_CLK, "sys_timer2_clk",
+			 "ref_clk", CCU_SYS_TIMER2_BASE, 17,
+			 CLK_SET_RATE_GATE, 0),
+	CCU_DIV_VAR_INFO(CCU_SYS_WDT_CLK, "sys_wdt_clk",
+			 "eth_clk", CCU_SYS_WDT_BASE, 17,
+			 CLK_SET_RATE_GATE, CCU_DIV_SKIP_ONE_TO_THREE)
+};
+
+static const struct ccu_div_rst_map sys_rst_map[] = {
+	CCU_DIV_RST_MAP(CCU_SYS_SATA_REF_RST, CCU_SYS_SATA_REF_CLK),
+	CCU_DIV_RST_MAP(CCU_SYS_APB_RST, CCU_SYS_APB_CLK),
+};
+
+static struct ccu_div *ccu_div_find_desc(struct ccu_div_data *data,
+					 unsigned int clk_id)
+{
+	struct ccu_div *div;
+	int idx;
+
+	for (idx = 0; idx < data->divs_num; ++idx) {
+		div = data->divs[idx];
+		if (div && div->id == clk_id)
+			return div;
+	}
+
+	return ERR_PTR(-EINVAL);
+}
+
+static int ccu_div_reset(struct reset_controller_dev *rcdev,
+			 unsigned long rst_id)
+{
+	struct ccu_div_data *data = to_ccu_div_data(rcdev);
+	const struct ccu_div_rst_map *map;
+	struct ccu_div *div;
+	int idx, ret;
+
+	for (idx = 0, map = data->rst_map; idx < data->rst_num; ++idx, ++map) {
+		if (map->rst_id == rst_id)
+			break;
+	}
+	if (idx == data->rst_num) {
+		pr_err("Invalid reset ID %lu specified\n", rst_id);
+		return -EINVAL;
+	}
+
+	div = ccu_div_find_desc(data, map->clk_id);
+	if (IS_ERR(div)) {
+		pr_err("Invalid clock ID %d in mapping\n", map->clk_id);
+		return PTR_ERR(div);
+	}
+
+	ret = ccu_div_reset_domain(div);
+	if (ret) {
+		pr_err("Reset isn't supported by divider %s\n",
+			clk_hw_get_name(ccu_div_get_clk_hw(div)));
+	}
+
+	return ret;
+}
+
+static const struct reset_control_ops ccu_div_rst_ops = {
+	.reset = ccu_div_reset,
+};
+
+static struct ccu_div_data *ccu_div_create_data(struct device_node *np)
+{
+	struct ccu_div_data *data;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	data->np = np;
+	if (of_device_is_compatible(np, "baikal,bt1-ccu-axi")) {
+		data->divs_num = ARRAY_SIZE(axi_info);
+		data->divs_info = axi_info;
+		data->rst_num = ARRAY_SIZE(axi_rst_map);
+		data->rst_map = axi_rst_map;
+	} else if (of_device_is_compatible(np, "baikal,bt1-ccu-sys")) {
+		data->divs_num = ARRAY_SIZE(sys_info);
+		data->divs_info = sys_info;
+		data->rst_num = ARRAY_SIZE(sys_rst_map);
+		data->rst_map = sys_rst_map;
+	} else {
+		pr_err("Uncompatible DT node '%s' specified\n",
+			of_node_full_name(np));
+		ret = -EINVAL;
+		goto err_kfree_data;
+	}
+
+	data->divs = kcalloc(data->divs_num, sizeof(*data->divs), GFP_KERNEL);
+	if (!data->divs) {
+		ret = -ENOMEM;
+		goto err_kfree_data;
+	}
+
+	return data;
+
+err_kfree_data:
+	kfree(data);
+
+	return ERR_PTR(ret);
+}
+
+static void ccu_div_free_data(struct ccu_div_data *data)
+{
+	kfree(data->divs);
+
+	kfree(data);
+}
+
+static int ccu_div_find_sys_regs(struct ccu_div_data *data)
+{
+	data->sys_regs = syscon_node_to_regmap(data->np->parent);
+	if (IS_ERR(data->sys_regs)) {
+		pr_err("Failed to find syscon regs for '%s'\n",
+			of_node_full_name(data->np));
+		return PTR_ERR(data->sys_regs);
+	}
+
+	return 0;
+}
+
+static struct clk_hw *ccu_div_of_clk_hw_get(struct of_phandle_args *clkspec,
+					    void *priv)
+{
+	struct ccu_div_data *data = priv;
+	struct ccu_div *div;
+	unsigned int clk_id;
+
+	clk_id = clkspec->args[0];
+	div = ccu_div_find_desc(data, clk_id);
+	if (IS_ERR(div)) {
+		pr_info("Invalid clock ID %d specified\n", clk_id);
+		return ERR_CAST(div);
+	}
+
+	return ccu_div_get_clk_hw(div);
+}
+
+static int ccu_div_clk_register(struct ccu_div_data *data)
+{
+	int idx, ret;
+
+	for (idx = 0; idx < data->divs_num; ++idx) {
+		const struct ccu_div_info *info = &data->divs_info[idx];
+		struct ccu_div_init_data init = {0};
+
+		init.id = info->id;
+		init.name = info->name;
+		init.parent_name = info->parent_name;
+		init.np = data->np;
+		init.type = info->type;
+		init.flags = info->flags;
+		init.features = info->features;
+
+		if (init.type == CCU_DIV_VAR) {
+			init.base = info->base;
+			init.sys_regs = data->sys_regs;
+			init.width = info->width;
+		} else if (init.type == CCU_DIV_GATE) {
+			init.base = info->base;
+			init.sys_regs = data->sys_regs;
+			init.divider = info->divider;
+		} else {
+			init.divider = info->divider;
+		}
+
+		data->divs[idx] = ccu_div_hw_register(&init);
+		if (IS_ERR(data->divs[idx])) {
+			ret = PTR_ERR(data->divs[idx]);
+			pr_err("Couldn't register divider '%s' hw\n",
+				init.name);
+			goto err_hw_unregister;
+		}
+	}
+
+	ret = of_clk_add_hw_provider(data->np, ccu_div_of_clk_hw_get, data);
+	if (ret) {
+		pr_err("Couldn't register dividers '%s' clock provider\n",
+			of_node_full_name(data->np));
+		goto err_hw_unregister;
+	}
+
+	return 0;
+
+err_hw_unregister:
+	for (--idx; idx >= 0; --idx)
+		ccu_div_hw_unregister(data->divs[idx]);
+
+	return ret;
+}
+
+static void ccu_div_clk_unregister(struct ccu_div_data *data)
+{
+	int idx;
+
+	of_clk_del_provider(data->np);
+
+	for (idx = 0; idx < data->divs_num; ++idx)
+		ccu_div_hw_unregister(data->divs[idx]);
+}
+
+static int ccu_div_rst_register(struct ccu_div_data *data)
+{
+	int ret;
+
+	data->rcdev.ops = &ccu_div_rst_ops;
+	data->rcdev.of_node = data->np;
+	data->rcdev.nr_resets = data->rst_num;
+
+	ret = reset_controller_register(&data->rcdev);
+	if (ret)
+		pr_err("Couldn't register divider '%s' reset controller\n",
+			of_node_full_name(data->np));
+
+	return ret;
+}
+
+static void ccu_div_init(struct device_node *np)
+{
+	struct ccu_div_data *data;
+	int ret;
+
+	data = ccu_div_create_data(np);
+	if (IS_ERR(data))
+		return;
+
+	ret = ccu_div_find_sys_regs(data);
+	if (ret)
+		goto err_free_data;
+
+	ret = ccu_div_clk_register(data);
+	if (ret)
+		goto err_free_data;
+
+	ret = ccu_div_rst_register(data);
+	if (ret)
+		goto err_clk_unregister;
+
+	return;
+
+err_clk_unregister:
+	ccu_div_clk_unregister(data);
+
+err_free_data:
+	ccu_div_free_data(data);
+
+	return;
+}
+
+CLK_OF_DECLARE(ccu_axi, "baikal,bt1-ccu-axi", ccu_div_init);
+CLK_OF_DECLARE(ccu_sys, "baikal,bt1-ccu-sys", ccu_div_init);
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 11+ messages in thread

* Re: [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding
  2020-05-26 22:20 ` [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding Serge Semin
@ 2020-05-29 17:54   ` Rob Herring
  2020-05-30 18:14   ` Stephen Boyd
  1 sibling, 0 replies; 11+ messages in thread
From: Rob Herring @ 2020-05-29 17:54 UTC (permalink / raw)
  To: Serge Semin
  Cc: Arnd Bergmann, linux-clk, linux-kernel, linux-mips,
	Thomas Bogendoerfer, Serge Semin, Rob Herring, Michael Turquette,
	devicetree, Alexey Malahov, Stephen Boyd

On Wed, 27 May 2020 01:20:53 +0300, Serge Semin wrote:
> Baikal-T1 Clocks Control Unit is responsible for transformation of a
> signal coming from an external oscillator into clocks of various
> frequencies to propagate them then to the corresponding clocks
> consumers (either individual IP-blocks or clock domains). In order
> to create a set of high-frequency clocks the external signal is
> firstly handled by the embedded into CCU PLLs. So the corresponding
> dts-node is just a normal clock-provider node with standard set of
> properties. Note as being part of the Baikal-T1 System Controller its
> DT node is supposed to be a child the system controller node.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: linux-mips@vger.kernel.org
> 
> ---
> 
> Changelog v2:
> - Rearrange the SoBs.
> - Discard comments in the bindings file header.
> - Add dual GPL/BSD license.
> - Add spaces around the ASCII-graphics in the binding description.
> - Remove reference to Documentation/devicetree/bindings/clock/clock-bindings.txt
>   file.
> - Discard redundant object check against "/schemas/clock/clock.yaml#" schema.
> - Discard redundant descriptions of the "#clock-cells" property.
> - Remove "reg" property since from now the clock DT node is supposed to be
>   a child of the syscon-compatible system controller node.
> - Remove "clock-output-names" property support.
> - Replace "additionalProperties: false" with "unevaluatedProperties: false".
> - Lowercase the nodes name in the examples.
> - Use "clock-controller" node name suffix in the examples.
> - Remove unnecessary comments in the clocks dt-bindings header file.
> 
> Changelog v3:
> - Get the reg property back even though the driver is using the parental
>   syscon regmap.
> - The DT schema will live separately from the system controller, but the
>   corresponding sub-node of the later DT schema will $ref this one.
> ---
>  .../bindings/clock/baikal,bt1-ccu-pll.yaml    | 131 ++++++++++++++++++
>  include/dt-bindings/clock/bt1-ccu.h           |  16 +++
>  2 files changed, 147 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/baikal,bt1-ccu-pll.yaml
>  create mode 100644 include/dt-bindings/clock/bt1-ccu.h
> 

Reviewed-by: Rob Herring <robh@kernel.org>

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding
  2020-05-26 22:20 ` [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding Serge Semin
@ 2020-05-29 17:55   ` Rob Herring
  2020-05-30 18:14   ` Stephen Boyd
  1 sibling, 0 replies; 11+ messages in thread
From: Rob Herring @ 2020-05-29 17:55 UTC (permalink / raw)
  To: Serge Semin
  Cc: linux-clk, linux-kernel, devicetree, Thomas Bogendoerfer,
	Alexey Malahov, Philipp Zabel, Stephen Boyd, Arnd Bergmann,
	linux-mips, Michael Turquette, Rob Herring, Serge Semin

On Wed, 27 May 2020 01:20:54 +0300, Serge Semin wrote:
> 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. The second block dividers alter the PLLs output signals to be then
> consumed by SoC peripheral devices. Both block DT nodes are ordinary
> clock-providers with standard set of properties supported. But in addition
> to that each clock provider can be used to reset the corresponding clock
> domain. This makes the AXI-bus and System Devices CCU DT nodes to be also
> reset-providers.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: linux-mips@vger.kernel.org
> 
> ---
> 
> Changelog v2:
> - Rearrange the SoBs.
> - Combine AXI-bus and System Devices CCU bindings into a single file.
> - Discard comments in the bindings file header.
> - Add dual GPL/BSD license.
> - Add spaces around the ASCII-graphics in the binding description.
> - Remove reference to Documentation/devicetree/bindings/clock/clock-bindings.txt
>   file.
> - Discard redundant object check against "/schemas/clock/clock.yaml#" schema.
> - Discard redundant descriptions of "#clock-cells" and "#reset-cells"
>   properties.
> - Discard "reg" property since the CCU dividers DT nodes are supposed be
>   children of the syscon-compatible system controller node.
> - Remove "clock-output-names" property support.
> - Replace "additionalProperties: false" with "unevaluatedProperties: false".
> - Lowercase the nodes name in the examples.
> - Use "clock-controller" node name suffix in the examples.
> - Remove unnecessary comments in the clocks and resets dt-binding header
>   files.
> - Discard label definitions in the examples.
> 
> Changelog v3:
> - Get the reg property back even though the driver is using the parental
>   syscon regmap.
> - The DT schema will live separately from the system controller, but the
>   corresponding sub-node of the later DT schema will $ref this one.
> ---
>  .../bindings/clock/baikal,bt1-ccu-div.yaml    | 188 ++++++++++++++++++
>  include/dt-bindings/clock/bt1-ccu.h           |  32 +++
>  include/dt-bindings/reset/bt1-ccu.h           |  25 +++
>  3 files changed, 245 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/baikal,bt1-ccu-div.yaml
>  create mode 100644 include/dt-bindings/reset/bt1-ccu.h
> 

Reviewed-by: Rob Herring <robh@kernel.org>

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding
  2020-05-26 22:20 ` [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding Serge Semin
  2020-05-29 17:54   ` Rob Herring
@ 2020-05-30 18:14   ` Stephen Boyd
  1 sibling, 0 replies; 11+ messages in thread
From: Stephen Boyd @ 2020-05-30 18:14 UTC (permalink / raw)
  To: Michael Turquette, Rob Herring, Serge Semin, Thomas Bogendoerfer
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	linux-mips, linux-clk, devicetree, linux-kernel

Quoting Serge Semin (2020-05-26 15:20:53)
> Baikal-T1 Clocks Control Unit is responsible for transformation of a
> signal coming from an external oscillator into clocks of various
> frequencies to propagate them then to the corresponding clocks
> consumers (either individual IP-blocks or clock domains). In order
> to create a set of high-frequency clocks the external signal is
> firstly handled by the embedded into CCU PLLs. So the corresponding
> dts-node is just a normal clock-provider node with standard set of
> properties. Note as being part of the Baikal-T1 System Controller its
> DT node is supposed to be a child the system controller node.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: linux-mips@vger.kernel.org
> 
> ---

Applied to clk-next

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding
  2020-05-26 22:20 ` [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding Serge Semin
  2020-05-29 17:55   ` Rob Herring
@ 2020-05-30 18:14   ` Stephen Boyd
  1 sibling, 0 replies; 11+ messages in thread
From: Stephen Boyd @ 2020-05-30 18:14 UTC (permalink / raw)
  To: Michael Turquette, Philipp Zabel, Rob Herring, Serge Semin,
	Thomas Bogendoerfer
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	linux-mips, linux-clk, devicetree, linux-kernel

Quoting Serge Semin (2020-05-26 15:20:54)
> 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. The second block dividers alter the PLLs output signals to be then
> consumed by SoC peripheral devices. Both block DT nodes are ordinary
> clock-providers with standard set of properties supported. But in addition
> to that each clock provider can be used to reset the corresponding clock
> domain. This makes the AXI-bus and System Devices CCU DT nodes to be also
> reset-providers.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: linux-mips@vger.kernel.org
> 
> ---

Applied to clk-next

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v3 3/4] clk: Add Baikal-T1 CCU PLLs driver
  2020-05-26 22:20 ` [PATCH v3 3/4] clk: Add Baikal-T1 CCU PLLs driver Serge Semin
@ 2020-05-30 18:14   ` Stephen Boyd
  0 siblings, 0 replies; 11+ messages in thread
From: Stephen Boyd @ 2020-05-30 18:14 UTC (permalink / raw)
  To: Michael Turquette, Serge Semin, Thomas Bogendoerfer
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	Rob Herring, linux-mips, devicetree, linux-kernel, linux-clk

Quoting Serge Semin (2020-05-26 15:20:55)
> Baikal-T1 is supposed to be supplied with a high-frequency external
> oscillator. But in order to create signals suitable for each IP-block
> embedded into the SoC the oscillator output is primarily connected to
> a set of CCU PLLs. There are five of them to create clocks for the MIPS
> P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains.
> The last three domains though named by the biggest system interfaces in
> fact include nearly all of the rest SoC peripherals. Each of the PLLs is
> based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper
> (so called safe PLL' clocks switcher) to simplify the PLL configuration
> procedure.
> 
> This driver creates the of-based hardware clocks to use them then in
> the corresponding subsystems. In order to simplify the driver code we
> split the functionality up into the PLLs clocks operations and hardware
> clocks declaration/registration procedures.
> 
> Even though the PLLs are based on the same IP-core, they may have some
> differences. In particular, some CCU PLLs support the output clock change
> without gating them (like CPU or PCIe PLLs), while the others don't, some
> CCU PLLs are critical and aren't supposed to be gated. In order to cover
> all of these cases the hardware clocks driver is designed with an
> info-descriptor pattern. So there are special static descriptors declared
> for each PLL, which is then used to create a hardware clock with proper
> operations. Additionally debugfs-files are provided for each PLL' field
> to make sure the implemented rate-PLLs-dividers calculation algorithm is
> correct.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: linux-mips@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> 
> ---

Applied to clk-next

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v3 4/4] clk: Add Baikal-T1 CCU Dividers driver
  2020-05-26 22:20 ` [PATCH v3 4/4] clk: Add Baikal-T1 CCU Dividers driver Serge Semin
@ 2020-05-30 18:14   ` Stephen Boyd
  0 siblings, 0 replies; 11+ messages in thread
From: Stephen Boyd @ 2020-05-30 18:14 UTC (permalink / raw)
  To: Michael Turquette, Serge Semin, Thomas Bogendoerfer
  Cc: Serge Semin, Serge Semin, Alexey Malahov, Arnd Bergmann,
	Rob Herring, linux-mips, devicetree, linux-kernel, linux-clk

Quoting Serge Semin (2020-05-26 15:20:56)
> Nearly each Baikal-T1 IP-core is supposed to have a clock source
> of particular frequency. But since there are greater than five
> IP-blocks embedded into the SoC, the CCU PLLs can't fulfill all the
> needs. Baikal-T1 CCU provides a set of fixed and configurable clock
> dividers in order to generate a necessary signal for each chip
> sub-block.
> 
> This driver creates the of-based hardware clocks for each divider
> available in Baikal-T1 CCU. The same way as for PLLs we split the
> functionality up into the clocks operations (gate, ungate, set rate,
> etc) and hardware clocks declaration/registration procedures.
> 
> In accordance with the CCU documentation all its dividers are distributed
> into two CCU sub-blocks: AXI-bus and system devices reference clocks.
> The former sub-block is used to supply the clocks for AXI-bus interfaces
> (AXI clock domains) and the later one provides the SoC IP-cores reference
> clocks. Each sub-block is represented by a dedicated DT node, so they
> have different compatible strings to distinguish one from another.
> 
> For some reason CCU provides the dividers of different types. Some
> dividers can be gateable some can't, some are fixed while the others
> are variable, some have special divider' limitations, some've got a
> non-standard register layout and so on. In order to cover all of these
> cases the hardware clocks driver is designed with an info-descriptor
> pattern. So there are special static descriptors declared for the
> dividers of each type with additional flags describing the block
> peculiarity. These descriptors are then used to create hardware clocks
> with proper operations.
> 
> Some CCU dividers provide a way to reset a domain they generate
> a clock for. So the CCU AXI-bus and CCU system devices clock
> drivers also perform the reset controller registration.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: linux-mips@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> 
> ---

Applied to clk-next

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2020-05-30 18:14 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-26 22:20 [PATCH v3 0/4] clk: Add Baikal-T1 SoC Clock Control Unit support Serge Semin
2020-05-26 22:20 ` [PATCH v3 1/4] dt-bindings: clk: Add Baikal-T1 CCU PLLs binding Serge Semin
2020-05-29 17:54   ` Rob Herring
2020-05-30 18:14   ` Stephen Boyd
2020-05-26 22:20 ` [PATCH v3 2/4] dt-bindings: clk: Add Baikal-T1 CCU Dividers binding Serge Semin
2020-05-29 17:55   ` Rob Herring
2020-05-30 18:14   ` Stephen Boyd
2020-05-26 22:20 ` [PATCH v3 3/4] clk: Add Baikal-T1 CCU PLLs driver Serge Semin
2020-05-30 18:14   ` Stephen Boyd
2020-05-26 22:20 ` [PATCH v3 4/4] clk: Add Baikal-T1 CCU Dividers driver Serge Semin
2020-05-30 18:14   ` Stephen Boyd

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