[PATCH v4 0/6] Nuvoton WPCM450 clock and reset driver

[PATCH v4 0/6] Nuvoton WPCM450 clock and reset driver

[Jonathan Neuschäfer]

This series adds support for the clock and reset controller in the Nuvoton
WPCM450 SoC. This means that the clock rates for peripherals will be calculated
automatically based on the clock tree as it was preconfigured by the bootloader.
The 24 MHz dummy clock, that is currently in the devicetree, is no longer needed.
Somewhat unfortunately, this also means that there is a breaking change once
the devicetree starts relying on the clock driver, but I find it acceptable in
this case, because WPCM450 is still at a somewhat early stage.


Upstreaming plan (although other suggestions are welcome):

Once reviewed,

- The ARM/dts changes should go through Joel Stanley's bmc tree
- The clocksource/timer changes should probably go via Daniel Lezcano and TIP
- The watchdog patch should go via the watchdog tree
- The clock controller bindings and driver should go through the clk tree
- It might make sense to delay the final ARM/dts patch ("ARM: dts: wpcm450:
  Switch clocks to clock controller") until next cycle to make sure it is
  merged after the clock driver.


v4:
- Leave WDT clock running during after restart handler
- Fix reset controller initialization
- Dropped patch 2/7 (clocksource: timer-npcm7xx: Enable timer 1 clock before use),
  as it was applied by Daniel Lezcano

v3:
- https://lore.kernel.org/lkml/20220508194333.2170161-1-j.neuschaefer@gmx.net/
- Changed "refclk" string to "ref"
- Fixed some dead code in the driver
- Added clk_prepare_enable call to the watchdog restart handler
- Added a few review tags

v2:
- https://lore.kernel.org/lkml/20220429172030.398011-1-j.neuschaefer@gmx.net/
- various small improvements

v1:
- https://lore.kernel.org/lkml/20220422183012.444674-1-j.neuschaefer@gmx.net/

Jonathan Neuschäfer (6):
  dt-bindings: timer: nuvoton,npcm7xx-timer: Allow specifying all clocks
  watchdog: npcm: Enable clock if provided
  dt-bindings: clock: Add Nuvoton WPCM450 clock/reset controller
  ARM: dts: wpcm450: Add clock controller node
  clk: wpcm450: Add Nuvoton WPCM450 clock/reset controller driver
  ARM: dts: wpcm450: Switch clocks to clock controller

 .../bindings/clock/nuvoton,wpcm450-clk.yaml   |  66 ++++
 .../bindings/timer/nuvoton,npcm7xx-timer.yaml |   8 +-
 arch/arm/boot/dts/nuvoton-wpcm450.dtsi        |  29 +-
 drivers/clk/Makefile                          |   1 +
 drivers/clk/clk-wpcm450.c                     | 364 ++++++++++++++++++
 drivers/reset/Kconfig                         |   2 +-
 drivers/watchdog/npcm_wdt.c                   |  16 +
 .../dt-bindings/clock/nuvoton,wpcm450-clk.h   |  67 ++++
 8 files changed, 544 insertions(+), 9 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/clock/nuvoton,wpcm450-clk.yaml
 create mode 100644 drivers/clk/clk-wpcm450.c
 create mode 100644 include/dt-bindings/clock/nuvoton,wpcm450-clk.h

--
2.35.1

[PATCH v4 1/6] dt-bindings: timer: nuvoton,npcm7xx-timer: Allow specifying all clocks

[Jonathan Neuschäfer]

The timer module contains multiple timers. In the WPCM450 SoC, each timer
runs off a clock can be gated individually. To model this correctly, the
timer node in the devicetree needs to take multiple clock inputs.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Rob Herring <robh@kernel.org>
---

v4:
- no changes

v3:
- Add R-b tag

v2:
- no changes
---
 .../devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml  | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml b/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml
index 0cbc26a721514..023c999113c38 100644
--- a/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml
+++ b/Documentation/devicetree/bindings/timer/nuvoton,npcm7xx-timer.yaml
@@ -23,7 +23,13 @@ properties:
       - description: The timer interrupt of timer 0

   clocks:
-    maxItems: 1
+    items:
+      - description: The reference clock for timer 0
+      - description: The reference clock for timer 1
+      - description: The reference clock for timer 2
+      - description: The reference clock for timer 3
+      - description: The reference clock for timer 4
+    minItems: 1

 required:
   - compatible
--
2.35.1

[PATCH v4 2/6] watchdog: npcm: Enable clock if provided

[Jonathan Neuschäfer]

On the Nuvoton WPCM450 SoC, with its upcoming clock driver, peripheral
clocks are individually gated and ungated. Therefore, the watchdog
driver must be able to ungate the watchdog clock.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
---

v4:
- Don't disable clock in npcm_wdt_restart function

v3:
- https://lore.kernel.org/lkml/20220508194333.2170161-4-j.neuschaefer@gmx.net/
- Add enable/disable calls to npcm_wdt_restart handler
- Not applied due to the above change:  Acked-by: Guenter Roeck <linux@roeck-us.net>

v2:
- https://lore.kernel.org/lkml/20220429172030.398011-4-j.neuschaefer@gmx.net/
- Add clk_disable_unprepare call, suggested by Guenter Roeck

v1:
- https://lore.kernel.org/lkml/20220422183012.444674-4-j.neuschaefer@gmx.net/
---
 drivers/watchdog/npcm_wdt.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/watchdog/npcm_wdt.c b/drivers/watchdog/npcm_wdt.c
index 28a24caa2627c..a5dd1c2301374 100644
--- a/drivers/watchdog/npcm_wdt.c
+++ b/drivers/watchdog/npcm_wdt.c
@@ -3,6 +3,7 @@
 // Copyright (c) 2018 IBM Corp.

 #include <linux/bitops.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -43,6 +44,7 @@
 struct npcm_wdt {
 	struct watchdog_device  wdd;
 	void __iomem		*reg;
+	struct clk		*clk;
 };

 static inline struct npcm_wdt *to_npcm_wdt(struct watchdog_device *wdd)
@@ -66,6 +68,9 @@ static int npcm_wdt_start(struct watchdog_device *wdd)
 	struct npcm_wdt *wdt = to_npcm_wdt(wdd);
 	u32 val;

+	if (wdt->clk)
+		clk_prepare_enable(wdt->clk);
+
 	if (wdd->timeout < 2)
 		val = 0x800;
 	else if (wdd->timeout < 3)
@@ -100,6 +105,9 @@ static int npcm_wdt_stop(struct watchdog_device *wdd)

 	writel(0, wdt->reg);

+	if (wdt->clk)
+		clk_disable_unprepare(wdt->clk);
+
 	return 0;
 }

@@ -147,6 +155,10 @@ static int npcm_wdt_restart(struct watchdog_device *wdd,
 {
 	struct npcm_wdt *wdt = to_npcm_wdt(wdd);

+	/* For reset, we start the WDT clock and leave it running. */
+	if (wdt->clk)
+		clk_prepare_enable(wdt->clk);
+
 	writel(NPCM_WTR | NPCM_WTRE | NPCM_WTE, wdt->reg);
 	udelay(1000);

@@ -191,6 +203,10 @@ static int npcm_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(wdt->reg))
 		return PTR_ERR(wdt->reg);

+	wdt->clk = devm_clk_get_optional(&pdev->dev, NULL);
+	if (IS_ERR(wdt->clk))
+		return PTR_ERR(wdt->clk);
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return irq;
--
2.35.1

[PATCH v4 3/6] dt-bindings: clock: Add Nuvoton WPCM450 clock/reset controller

[Jonathan Neuschäfer]

The Nuvoton WPCM450 SoC has a combined clock and reset controller.
Add a devicetree binding for it, as well as definitions for the bit
numbers used by it.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---

v4:
- Add R-b tag

v3:
- Change clock-output-names and clock-names from "refclk" to "ref", suggested
  by Krzysztof Kozlowski

v2:
- https://lore.kernel.org/lkml/20220429172030.398011-5-j.neuschaefer@gmx.net/
- Various improvements, suggested by Krzysztof Kozlowski

v1:
- https://lore.kernel.org/lkml/20220422183012.444674-5-j.neuschaefer@gmx.net/
---
 .../bindings/clock/nuvoton,wpcm450-clk.yaml   | 66 ++++++++++++++++++
 .../dt-bindings/clock/nuvoton,wpcm450-clk.h   | 67 +++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/nuvoton,wpcm450-clk.yaml
 create mode 100644 include/dt-bindings/clock/nuvoton,wpcm450-clk.h

diff --git a/Documentation/devicetree/bindings/clock/nuvoton,wpcm450-clk.yaml b/Documentation/devicetree/bindings/clock/nuvoton,wpcm450-clk.yaml
new file mode 100644
index 0000000000000..525024a58df4c
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/nuvoton,wpcm450-clk.yaml
@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/nuvoton,wpcm450-clk.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton WPCM450 clock controller
+
+maintainers:
+  - Jonathan Neuschäfer <j.neuschaefer@gmx.net>
+
+description:
+  The clock controller of the Nuvoton WPCM450 SoC supplies clocks and resets to
+  the rest of the chip.
+
+properties:
+  compatible:
+    const: nuvoton,wpcm450-clk
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Reference clock oscillator (should be 48 MHz)
+
+  clock-names:
+    items:
+      - const: ref
+
+  '#clock-cells':
+    const: 1
+
+  '#reset-cells':
+    const: 1
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - '#clock-cells'
+
+examples:
+  - |
+    #include <dt-bindings/clock/nuvoton,wpcm450-clk.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    refclk: clock-48mhz {
+      /* 48 MHz reference oscillator */
+      compatible = "fixed-clock";
+      clock-output-names = "ref";
+      clock-frequency = <48000000>;
+      #clock-cells = <0>;
+    };
+
+    clk: clock-controller@b0000200 {
+      reg = <0xb0000200 0x100>;
+      compatible = "nuvoton,wpcm450-clk";
+      clocks = <&refclk>;
+      clock-names = "ref";
+      #clock-cells = <1>;
+      #reset-cells = <1>;
+    };
diff --git a/include/dt-bindings/clock/nuvoton,wpcm450-clk.h b/include/dt-bindings/clock/nuvoton,wpcm450-clk.h
new file mode 100644
index 0000000000000..86e1c895921b7
--- /dev/null
+++ b/include/dt-bindings/clock/nuvoton,wpcm450-clk.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+
+#ifndef _DT_BINDINGS_CLOCK_NUVOTON_WPCM450_CLK_H
+#define _DT_BINDINGS_CLOCK_NUVOTON_WPCM450_CLK_H
+
+/* Clocks based on CLKEN bits */
+#define WPCM450_CLK_FIU            0
+#define WPCM450_CLK_XBUS           1
+#define WPCM450_CLK_KCS            2
+#define WPCM450_CLK_SHM            4
+#define WPCM450_CLK_USB1           5
+#define WPCM450_CLK_EMC0           6
+#define WPCM450_CLK_EMC1           7
+#define WPCM450_CLK_USB0           8
+#define WPCM450_CLK_PECI           9
+#define WPCM450_CLK_AES           10
+#define WPCM450_CLK_UART0         11
+#define WPCM450_CLK_UART1         12
+#define WPCM450_CLK_SMB2          13
+#define WPCM450_CLK_SMB3          14
+#define WPCM450_CLK_SMB4          15
+#define WPCM450_CLK_SMB5          16
+#define WPCM450_CLK_HUART         17
+#define WPCM450_CLK_PWM           18
+#define WPCM450_CLK_TIMER0        19
+#define WPCM450_CLK_TIMER1        20
+#define WPCM450_CLK_TIMER2        21
+#define WPCM450_CLK_TIMER3        22
+#define WPCM450_CLK_TIMER4        23
+#define WPCM450_CLK_MFT0          24
+#define WPCM450_CLK_MFT1          25
+#define WPCM450_CLK_WDT           26
+#define WPCM450_CLK_ADC           27
+#define WPCM450_CLK_SDIO          28
+#define WPCM450_CLK_SSPI          29
+#define WPCM450_CLK_SMB0          30
+#define WPCM450_CLK_SMB1          31
+
+/* Other clocks */
+#define WPCM450_CLK_USBPHY        32
+
+#define WPCM450_NUM_CLKS          33
+
+/* Resets based on IPSRST bits */
+#define WPCM450_RESET_FIU          0
+#define WPCM450_RESET_EMC0         6
+#define WPCM450_RESET_EMC1         7
+#define WPCM450_RESET_USB0         8
+#define WPCM450_RESET_USB1         9
+#define WPCM450_RESET_AES_PECI    10
+#define WPCM450_RESET_UART        11
+#define WPCM450_RESET_MC          12
+#define WPCM450_RESET_SMB2        13
+#define WPCM450_RESET_SMB3        14
+#define WPCM450_RESET_SMB4        15
+#define WPCM450_RESET_SMB5        16
+#define WPCM450_RESET_PWM         18
+#define WPCM450_RESET_TIMER       19
+#define WPCM450_RESET_ADC         27
+#define WPCM450_RESET_SDIO        28
+#define WPCM450_RESET_SSPI        29
+#define WPCM450_RESET_SMB0        30
+#define WPCM450_RESET_SMB1        31
+
+#define WPCM450_NUM_RESETS        32
+
+#endif /* _DT_BINDINGS_CLOCK_NUVOTON_WPCM450_CLK_H */
--
2.35.1

[PATCH v4 4/6] ARM: dts: wpcm450: Add clock controller node

[Jonathan Neuschäfer]

This declares the clock controller and the necessary 48 Mhz reference
clock in the WPCM450 device. Switching devices over to the clock
controller is intentionally done in a separate patch to give time for
the clock controller driver to land.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
---

v4:
- no changes

v3:
- Change clock-output-names and clock-names from "refclk" to "ref"

v2:
- https://lore.kernel.org/lkml/20220429172030.398011-6-j.neuschaefer@gmx.net/
- no changes
---
 arch/arm/boot/dts/nuvoton-wpcm450.dtsi | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arm/boot/dts/nuvoton-wpcm450.dtsi b/arch/arm/boot/dts/nuvoton-wpcm450.dtsi
index b9b669cd632f1..332cc222c7dc5 100644
--- a/arch/arm/boot/dts/nuvoton-wpcm450.dtsi
+++ b/arch/arm/boot/dts/nuvoton-wpcm450.dtsi
@@ -37,6 +37,14 @@ clk24m: clock-24mhz {
 		#clock-cells = <0>;
 	};

+	refclk: clock-48mhz {
+		/* 48 MHz reference oscillator */
+		compatible = "fixed-clock";
+		clock-output-names = "ref";
+		clock-frequency = <48000000>;
+		#clock-cells = <0>;
+	};
+
 	soc {
 		compatible = "simple-bus";
 		#address-cells = <1>;
@@ -49,6 +57,15 @@ gcr: syscon@b0000000 {
 			reg = <0xb0000000 0x200>;
 		};

+		clk: clock-controller@b0000200 {
+			compatible = "nuvoton,wpcm450-clk";
+			reg = <0xb0000200 0x100>;
+			clocks = <&refclk>;
+			clock-names = "ref";
+			#clock-cells = <1>;
+			#reset-cells = <1>;
+		};
+
 		serial0: serial@b8000000 {
 			compatible = "nuvoton,wpcm450-uart";
 			reg = <0xb8000000 0x20>;
--
2.35.1

[PATCH v4 5/6] clk: wpcm450: Add Nuvoton WPCM450 clock/reset controller driver

[Jonathan Neuschäfer]

This driver implements the following features w.r.t. the clock and reset
controller in the WPCM450 SoC:

- It calculates the rates for all clocks managed by the clock controller
- It leaves the clock tree mostly unchanged, except that it enables/
  disables clock gates based on usage.
- It exposes the reset lines managed by the controller using the
  Generic Reset Controller subsystem

NOTE: If the driver and the corresponding devicetree node are present,
      the driver will disable "unused" clocks. This is problem until
      the clock relations are properly declared in the devicetree (in a
      later patch). Until then, the clk_ignore_unused kernel parameter
      can be used as a workaround.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
---

v4:
- Fix reset controller initialization

v3:
- https://lore.kernel.org/lkml/20220508194333.2170161-7-j.neuschaefer@gmx.net/
- Change reference clock name from "refclk" to "ref"
- Remove unused variable in return path of wpcm450_clk_register_pll
- Remove unused divisor tables

v2:
- https://lore.kernel.org/lkml/20220429172030.398011-7-j.neuschaefer@gmx.net/
- no changes
---
 drivers/clk/Makefile      |   1 +
 drivers/clk/clk-wpcm450.c | 364 ++++++++++++++++++++++++++++++++++++++
 drivers/reset/Kconfig     |   2 +-
 3 files changed, 366 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/clk-wpcm450.c

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index d5db170d38d2d..d6737e6d62feb 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_ARCH_VT8500)		+= clk-vt8500.o
 obj-$(CONFIG_COMMON_CLK_RS9_PCIE)	+= clk-renesas-pcie.o
 obj-$(CONFIG_COMMON_CLK_VC5)		+= clk-versaclock5.o
 obj-$(CONFIG_COMMON_CLK_WM831X)		+= clk-wm831x.o
+obj-$(CONFIG_ARCH_WPCM450)		+= clk-wpcm450.o
 obj-$(CONFIG_COMMON_CLK_XGENE)		+= clk-xgene.o

 # please keep this section sorted lexicographically by directory path name
diff --git a/drivers/clk/clk-wpcm450.c b/drivers/clk/clk-wpcm450.c
new file mode 100644
index 0000000000000..88fe5583e009d
--- /dev/null
+++ b/drivers/clk/clk-wpcm450.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton WPCM450 clock and reset controller driver.
+ *
+ * Copyright (C) 2022 Jonathan Neuschäfer <j.neuschaefer@gmx.net>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitfield.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/reset-controller.h>
+#include <linux/reset/reset-simple.h>
+#include <linux/slab.h>
+
+#include <dt-bindings/clock/nuvoton,wpcm450-clk.h>
+
+struct wpcm450_clk_pll {
+	struct clk_hw hw;
+	void __iomem *pllcon;
+	u8 flags;
+};
+
+#define to_wpcm450_clk_pll(_hw) container_of(_hw, struct wpcm450_clk_pll, hw)
+
+#define PLLCON_FBDV	GENMASK(24, 16)
+#define PLLCON_PRST	BIT(13)
+#define PLLCON_PWDEN	BIT(12)
+#define PLLCON_OTDV	GENMASK(10, 8)
+#define PLLCON_INDV	GENMASK(5, 0)
+
+static unsigned long wpcm450_clk_pll_recalc_rate(struct clk_hw *hw,
+						 unsigned long parent_rate)
+{
+	struct wpcm450_clk_pll *pll = to_wpcm450_clk_pll(hw);
+	unsigned long fbdv, indv, otdv;
+	u64 rate;
+	u32 pllcon;
+
+	if (parent_rate == 0) {
+		pr_err("%s: parent rate is zero", __func__);
+		return 0;
+	}
+
+	pllcon = readl_relaxed(pll->pllcon);
+
+	indv = FIELD_GET(PLLCON_INDV, pllcon) + 1;
+	fbdv = FIELD_GET(PLLCON_FBDV, pllcon) + 1;
+	otdv = FIELD_GET(PLLCON_OTDV, pllcon) + 1;
+
+	rate = (u64)parent_rate * fbdv;
+	do_div(rate, indv * otdv);
+
+	return rate;
+}
+
+static int wpcm450_clk_pll_is_enabled(struct clk_hw *hw)
+{
+	struct wpcm450_clk_pll *pll = to_wpcm450_clk_pll(hw);
+	u32 pllcon;
+
+	pllcon = readl_relaxed(pll->pllcon);
+
+	return !(pllcon & PLLCON_PRST);
+}
+
+static void wpcm450_clk_pll_disable(struct clk_hw *hw)
+{
+	struct wpcm450_clk_pll *pll = to_wpcm450_clk_pll(hw);
+	u32 pllcon;
+
+	pllcon = readl_relaxed(pll->pllcon);
+	pllcon |= PLLCON_PRST | PLLCON_PWDEN;
+	writel(pllcon, pll->pllcon);
+}
+
+static const struct clk_ops wpcm450_clk_pll_ops = {
+	.recalc_rate = wpcm450_clk_pll_recalc_rate,
+	.is_enabled = wpcm450_clk_pll_is_enabled,
+	.disable = wpcm450_clk_pll_disable
+};
+
+static struct clk_hw *
+wpcm450_clk_register_pll(void __iomem *pllcon, const char *name,
+			 const char *parent_name, unsigned long flags)
+{
+	struct wpcm450_clk_pll *pll;
+	struct clk_init_data init;
+	int ret;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &wpcm450_clk_pll_ops;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+	init.flags = flags;
+
+	pll->pllcon = pllcon;
+	pll->hw.init = &init;
+
+	ret = clk_hw_register(NULL, &pll->hw);
+	if (ret) {
+		kfree(pll);
+		return ERR_PTR(ret);
+	}
+
+	return &pll->hw;
+}
+
+#define REG_CLKEN	0x00
+#define REG_CLKSEL	0x04
+#define REG_CLKDIV	0x08
+#define REG_PLLCON0	0x0c
+#define REG_PLLCON1	0x10
+#define REG_PMCON	0x14
+#define REG_IRQWAKECON	0x18
+#define REG_IRQWAKEFLAG	0x1c
+#define REG_IPSRST	0x20
+
+struct wpcm450_pll_data {
+	const char *name;
+	const char *parent_name;
+	unsigned int reg;
+	unsigned long flags;
+};
+
+static const struct wpcm450_pll_data pll_data[] = {
+	{ "pll0", "ref", REG_PLLCON0, 0 },
+	{ "pll1", "ref", REG_PLLCON1, 0 },
+};
+
+struct wpcm450_clksel_data {
+	const char *name;
+	const char *const *parent_names;
+	unsigned int num_parents;
+	const u32 *table;
+	int shift;
+	int width;
+	int index;
+	unsigned long flags;
+};
+
+static const u32 parent_table[] = { 0, 1, 2 };
+static const char *const default_parents[] = { "pll0", "pll1", "ref" };
+static const char *const huart_parents[] = { "ref", "refdiv2" };
+
+static const struct wpcm450_clksel_data clksel_data[] = {
+	{ "cpusel", default_parents, ARRAY_SIZE(default_parents),
+		parent_table, 0, 2, -1, CLK_IS_CRITICAL },
+	{ "clkout", default_parents, ARRAY_SIZE(default_parents),
+		parent_table, 2, 2, -1, 0 },
+	{ "usbphy", default_parents, ARRAY_SIZE(default_parents),
+		parent_table, 6, 2, -1, 0 },
+	{ "uartsel", default_parents, ARRAY_SIZE(default_parents),
+		parent_table, 8, 2, WPCM450_CLK_USBPHY, 0 },
+	{ "huartsel", huart_parents, ARRAY_SIZE(huart_parents),
+		parent_table, 10, 1, -1, 0 },
+};
+
+static const struct clk_div_table div_fixed2[] = {
+	{ .val = 0, .div = 2 },
+	{ }
+};
+
+struct wpcm450_clkdiv_data {
+	const char *name;
+	const char *parent_name;
+	int div_flags;
+	const struct clk_div_table *table;
+	int shift;
+	int width;
+	unsigned long flags;
+};
+
+static struct wpcm450_clkdiv_data clkdiv_data_early[] = {
+	{ "refdiv2", "ref", 0, div_fixed2, 0, 0 },
+};
+
+static const struct wpcm450_clkdiv_data clkdiv_data[] = {
+	{ "cpu", "cpusel", 0, div_fixed2, 0, 0, CLK_IS_CRITICAL },
+	{ "adcdiv", "ref", CLK_DIVIDER_POWER_OF_TWO, NULL, 28, 2, 0 },
+	{ "apb", "ahb", CLK_DIVIDER_POWER_OF_TWO, NULL, 26, 2, 0 },
+	{ "ahb", "cpu", CLK_DIVIDER_POWER_OF_TWO, NULL, 24, 2, 0 },
+	{ "uart", "uartsel", 0, NULL, 16, 4, 0 },
+	{ "ahb3", "ahb", CLK_DIVIDER_POWER_OF_TWO, NULL, 8, 2, 0 },
+};
+
+struct wpcm450_clken_data {
+	const char *name;
+	const char *parent_name;
+	int bitnum;
+	unsigned long flags;
+};
+
+static const struct wpcm450_clken_data clken_data[] = {
+	{ "fiu", "ahb3", WPCM450_CLK_FIU, 0 },
+	{ "xbus", "ahb3", WPCM450_CLK_XBUS, 0 },
+	{ "kcs", "apb", WPCM450_CLK_KCS, 0 },
+	{ "shm", "ahb3", WPCM450_CLK_SHM, 0 },
+	{ "usb1", "ahb", WPCM450_CLK_USB1, 0 },
+	{ "emc0", "ahb", WPCM450_CLK_EMC0, 0 },
+	{ "emc1", "ahb", WPCM450_CLK_EMC1, 0 },
+	{ "usb0", "ahb", WPCM450_CLK_USB0, 0 },
+	{ "peci", "apb", WPCM450_CLK_PECI, 0 },
+	{ "aes", "apb", WPCM450_CLK_AES, 0 },
+	{ "uart0", "uart", WPCM450_CLK_UART0, 0 },
+	{ "uart1", "uart", WPCM450_CLK_UART1, 0 },
+	{ "smb2", "apb", WPCM450_CLK_SMB2, 0 },
+	{ "smb3", "apb", WPCM450_CLK_SMB3, 0 },
+	{ "smb4", "apb", WPCM450_CLK_SMB4, 0 },
+	{ "smb5", "apb", WPCM450_CLK_SMB5, 0 },
+	{ "huart", "huartsel", WPCM450_CLK_HUART, 0 },
+	{ "pwm", "apb", WPCM450_CLK_PWM, 0 },
+	{ "timer0", "refdiv2", WPCM450_CLK_TIMER0, 0 },
+	{ "timer1", "refdiv2", WPCM450_CLK_TIMER1, 0 },
+	{ "timer2", "refdiv2", WPCM450_CLK_TIMER2, 0 },
+	{ "timer3", "refdiv2", WPCM450_CLK_TIMER3, 0 },
+	{ "timer4", "refdiv2", WPCM450_CLK_TIMER4, 0 },
+	{ "mft0", "apb", WPCM450_CLK_MFT0, 0 },
+	{ "mft1", "apb", WPCM450_CLK_MFT1, 0 },
+	{ "wdt", "refdiv2", WPCM450_CLK_WDT, 0 },
+	{ "adc", "adcdiv", WPCM450_CLK_ADC, 0 },
+	{ "sdio", "ahb", WPCM450_CLK_SDIO, 0 },
+	{ "sspi", "apb", WPCM450_CLK_SSPI, 0 },
+	{ "smb0", "apb", WPCM450_CLK_SMB0, 0 },
+	{ "smb1", "apb", WPCM450_CLK_SMB1, 0 },
+};
+
+static DEFINE_SPINLOCK(wpcm450_clk_lock);
+
+static void __init wpcm450_clk_init(struct device_node *clk_np)
+{
+	struct clk_hw_onecell_data *clk_data;
+	static struct clk_hw **hws;
+	static struct clk_hw *hw;
+	void __iomem *clk_base;
+	int i, ret;
+	struct reset_simple_data *reset;
+
+	clk_base = of_iomap(clk_np, 0);
+	if (!clk_base) {
+		pr_err("%pOFP: failed to map registers\n", clk_np);
+		of_node_put(clk_np);
+		return;
+	}
+	of_node_put(clk_np);
+
+	clk_data = kzalloc(struct_size(clk_data, hws, WPCM450_NUM_CLKS), GFP_KERNEL);
+	if (!clk_data)
+		goto err_unmap;
+
+	clk_data->num = WPCM450_NUM_CLKS;
+	hws = clk_data->hws;
+
+	for (i = 0; i < WPCM450_NUM_CLKS; i++)
+		hws[i] = ERR_PTR(-ENOENT);
+
+	// PLLs
+	for (i = 0; i < ARRAY_SIZE(pll_data); i++) {
+		const struct wpcm450_pll_data *data = &pll_data[i];
+
+		hw = wpcm450_clk_register_pll(clk_base + data->reg, data->name,
+					      data->parent_name, data->flags);
+		if (IS_ERR(hw)) {
+			pr_info("Failed to register PLL: %pe", hw);
+			goto err_free;
+		}
+	}
+
+	// Early divisors (REF/2)
+	for (i = 0; i < ARRAY_SIZE(clkdiv_data_early); i++) {
+		const struct wpcm450_clkdiv_data *data = &clkdiv_data_early[i];
+
+		hw = clk_hw_register_divider_table(NULL, data->name, data->parent_name,
+						   data->flags, clk_base + REG_CLKDIV,
+						   data->shift, data->width, data->div_flags,
+						   data->table, &wpcm450_clk_lock);
+		if (IS_ERR(hw)) {
+			pr_err("Failed to register div table: %pe\n", hw);
+			goto err_free;
+		}
+	}
+
+	// Selects/muxes
+	for (i = 0; i < ARRAY_SIZE(clksel_data); i++) {
+		const struct wpcm450_clksel_data *data = &clksel_data[i];
+
+		hw = clk_hw_register_mux_table(NULL, data->name, data->parent_names,
+					       data->num_parents, data->flags,
+					       clk_base + REG_CLKSEL, data->shift,
+					       BIT(data->width) - 1, 0, data->table,
+					       &wpcm450_clk_lock);
+		if (IS_ERR(hw)) {
+			pr_err("Failed to register mux: %pe\n", hw);
+			goto err_free;
+		}
+		if (data->index >= 0)
+			clk_data->hws[data->index] = hw;
+	}
+
+	// Divisors
+	for (i = 0; i < ARRAY_SIZE(clkdiv_data); i++) {
+		const struct wpcm450_clkdiv_data *data = &clkdiv_data[i];
+
+		hw = clk_hw_register_divider_table(NULL, data->name, data->parent_name,
+						   data->flags, clk_base + REG_CLKDIV,
+						   data->shift, data->width, data->div_flags,
+						   data->table, &wpcm450_clk_lock);
+		if (IS_ERR(hw)) {
+			pr_err("Failed to register divider: %pe\n", hw);
+			goto err_free;
+		}
+	}
+
+	// Enables/gates
+	for (i = 0; i < ARRAY_SIZE(clken_data); i++) {
+		const struct wpcm450_clken_data *data = &clken_data[i];
+
+		hw = clk_hw_register_gate(NULL, data->name, data->parent_name, data->flags,
+					  clk_base + REG_CLKEN, data->bitnum,
+					  data->flags, &wpcm450_clk_lock);
+		if (IS_ERR(hw)) {
+			pr_err("Failed to register gate: %pe\n", hw);
+			goto err_free;
+		}
+		clk_data->hws[data->bitnum] = hw;
+	}
+
+	ret = of_clk_add_hw_provider(clk_np, of_clk_hw_onecell_get, clk_data);
+	if (ret)
+		pr_err("Failed to add DT provider: %d\n", ret);
+
+	// Reset controller
+	reset = kzalloc(sizeof(*reset), GFP_KERNEL);
+	if (!reset)
+		goto err_free;
+	reset->rcdev.owner = THIS_MODULE;
+	reset->rcdev.nr_resets = WPCM450_NUM_RESETS;
+	reset->rcdev.ops = &reset_simple_ops;
+	reset->rcdev.of_node = clk_np;
+	reset->membase = clk_base + REG_IPSRST;
+	ret = reset_controller_register(&reset->rcdev);
+	if (ret)
+		pr_err("Failed to register reset controller: %d\n", ret);
+
+	of_node_put(clk_np);
+	return;
+
+err_free:
+	kfree(clk_data->hws);
+err_unmap:
+	iounmap(clk_base);
+	of_node_put(clk_np);
+}
+
+CLK_OF_DECLARE(wpcm450_clk_init, "nuvoton,wpcm450-clk", wpcm450_clk_init);
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 93c8d07ee3280..1e9badf8878bb 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -201,7 +201,7 @@ config RESET_SCMI

 config RESET_SIMPLE
 	bool "Simple Reset Controller Driver" if COMPILE_TEST
-	default ARCH_ASPEED || ARCH_BCM4908 || ARCH_BITMAIN || ARCH_REALTEK || ARCH_STM32 || (ARCH_INTEL_SOCFPGA && ARM64) || ARCH_SUNXI || ARC
+	default ARCH_ASPEED || ARCH_BCM4908 || ARCH_BITMAIN || ARCH_REALTEK || ARCH_STM32 || (ARCH_INTEL_SOCFPGA && ARM64) || ARCH_SUNXI || ARC || ARCH_NPCM
 	help
 	  This enables a simple reset controller driver for reset lines that
 	  that can be asserted and deasserted by toggling bits in a contiguous,
--
2.35.1

[PATCH v4 6/6] ARM: dts: wpcm450: Switch clocks to clock controller

[Jonathan Neuschäfer]

This change is incompatible with older kernels because it requires the
clock controller driver, but I think that's acceptable because WPCM450
support is generally still in an early phase.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
---

v2-v4:
- no changes
---
 arch/arm/boot/dts/nuvoton-wpcm450.dtsi | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/arm/boot/dts/nuvoton-wpcm450.dtsi b/arch/arm/boot/dts/nuvoton-wpcm450.dtsi
index 332cc222c7dc5..439f9047ad651 100644
--- a/arch/arm/boot/dts/nuvoton-wpcm450.dtsi
+++ b/arch/arm/boot/dts/nuvoton-wpcm450.dtsi
@@ -2,6 +2,7 @@
 // Copyright 2021 Jonathan Neuschäfer

 #include <dt-bindings/interrupt-controller/irq.h>
+#include <dt-bindings/clock/nuvoton,wpcm450-clk.h>

 / {
 	compatible = "nuvoton,wpcm450";
@@ -30,13 +31,6 @@ cpu@0 {
 		};
 	};

-	clk24m: clock-24mhz {
-		/* 24 MHz dummy clock */
-		compatible = "fixed-clock";
-		clock-frequency = <24000000>;
-		#clock-cells = <0>;
-	};
-
 	refclk: clock-48mhz {
 		/* 48 MHz reference oscillator */
 		compatible = "fixed-clock";
@@ -71,7 +65,7 @@ serial0: serial@b8000000 {
 			reg = <0xb8000000 0x20>;
 			reg-shift = <2>;
 			interrupts = <7 IRQ_TYPE_LEVEL_HIGH>;
-			clocks = <&clk24m>;
+			clocks = <&clk WPCM450_CLK_UART0>;
 			pinctrl-names = "default";
 			pinctrl-0 = <&bsp_pins>;
 			status = "disabled";
@@ -82,7 +76,7 @@ serial1: serial@b8000100 {
 			reg = <0xb8000100 0x20>;
 			reg-shift = <2>;
 			interrupts = <8 IRQ_TYPE_LEVEL_HIGH>;
-			clocks = <&clk24m>;
+			clocks = <&clk WPCM450_CLK_UART1>;
 			status = "disabled";
 		};

@@ -90,14 +84,18 @@ timer0: timer@b8001000 {
 			compatible = "nuvoton,wpcm450-timer";
 			interrupts = <12 IRQ_TYPE_LEVEL_HIGH>;
 			reg = <0xb8001000 0x1c>;
-			clocks = <&clk24m>;
+			clocks = <&clk WPCM450_CLK_TIMER0>,
+				 <&clk WPCM450_CLK_TIMER1>,
+				 <&clk WPCM450_CLK_TIMER2>,
+				 <&clk WPCM450_CLK_TIMER3>,
+				 <&clk WPCM450_CLK_TIMER4>;
 		};

 		watchdog0: watchdog@b800101c {
 			compatible = "nuvoton,wpcm450-wdt";
 			interrupts = <1 IRQ_TYPE_LEVEL_HIGH>;
 			reg = <0xb800101c 0x4>;
-			clocks = <&clk24m>;
+			clocks = <&clk WPCM450_CLK_WDT>;
 		};

 		aic: interrupt-controller@b8002000 {
--
2.35.1

Re: [PATCH v4 2/6] watchdog: npcm: Enable clock if provided

[Guenter Roeck]

On Fri, Jun 10, 2022 at 09:21:37AM +0200, Jonathan Neuschäfer wrote:
> On the Nuvoton WPCM450 SoC, with its upcoming clock driver, peripheral
> clocks are individually gated and ungated. Therefore, the watchdog
> driver must be able to ungate the watchdog clock.
> 
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> 
> v4:
> - Don't disable clock in npcm_wdt_restart function
> 
> v3:
> - https://lore.kernel.org/lkml/20220508194333.2170161-4-j.neuschaefer@gmx.net/
> - Add enable/disable calls to npcm_wdt_restart handler
> - Not applied due to the above change:  Acked-by: Guenter Roeck <linux@roeck-us.net>
> 
> v2:
> - https://lore.kernel.org/lkml/20220429172030.398011-4-j.neuschaefer@gmx.net/
> - Add clk_disable_unprepare call, suggested by Guenter Roeck
> 
> v1:
> - https://lore.kernel.org/lkml/20220422183012.444674-4-j.neuschaefer@gmx.net/
> ---
>  drivers/watchdog/npcm_wdt.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> --
> 2.35.1
> 
> diff --git a/drivers/watchdog/npcm_wdt.c b/drivers/watchdog/npcm_wdt.c
> index 28a24caa2627c..a5dd1c2301374 100644
> --- a/drivers/watchdog/npcm_wdt.c
> +++ b/drivers/watchdog/npcm_wdt.c
> @@ -3,6 +3,7 @@
>  // Copyright (c) 2018 IBM Corp.
> 
>  #include <linux/bitops.h>
> +#include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/interrupt.h>
>  #include <linux/kernel.h>
> @@ -43,6 +44,7 @@
>  struct npcm_wdt {
>  	struct watchdog_device  wdd;
>  	void __iomem		*reg;
> +	struct clk		*clk;
>  };
> 
>  static inline struct npcm_wdt *to_npcm_wdt(struct watchdog_device *wdd)
> @@ -66,6 +68,9 @@ static int npcm_wdt_start(struct watchdog_device *wdd)
>  	struct npcm_wdt *wdt = to_npcm_wdt(wdd);
>  	u32 val;
> 
> +	if (wdt->clk)
> +		clk_prepare_enable(wdt->clk);
> +
>  	if (wdd->timeout < 2)
>  		val = 0x800;
>  	else if (wdd->timeout < 3)
> @@ -100,6 +105,9 @@ static int npcm_wdt_stop(struct watchdog_device *wdd)
> 
>  	writel(0, wdt->reg);
> 
> +	if (wdt->clk)
> +		clk_disable_unprepare(wdt->clk);
> +
>  	return 0;
>  }
> 
> @@ -147,6 +155,10 @@ static int npcm_wdt_restart(struct watchdog_device *wdd,
>  {
>  	struct npcm_wdt *wdt = to_npcm_wdt(wdd);
> 
> +	/* For reset, we start the WDT clock and leave it running. */
> +	if (wdt->clk)
> +		clk_prepare_enable(wdt->clk);
> +
>  	writel(NPCM_WTR | NPCM_WTRE | NPCM_WTE, wdt->reg);
>  	udelay(1000);
> 
> @@ -191,6 +203,10 @@ static int npcm_wdt_probe(struct platform_device *pdev)
>  	if (IS_ERR(wdt->reg))
>  		return PTR_ERR(wdt->reg);
> 
> +	wdt->clk = devm_clk_get_optional(&pdev->dev, NULL);
> +	if (IS_ERR(wdt->clk))
> +		return PTR_ERR(wdt->clk);
> +
>  	irq = platform_get_irq(pdev, 0);
>  	if (irq < 0)
>  		return irq;