[PATCH v7 0/2] riscv: pwm: sophgo: add pwm support for CV1800

[PATCH v7 0/2] riscv: pwm: sophgo: add pwm support for CV1800

[Jingbao Qiu]

The Sophgo CV1800 chip provides a set of four independent
PWM channel outputs.
This series adds PWM controller support for Sophgo cv1800.

Changes since v6:
- add detailed Limitations
- using BIT(n) instead BIT(0) << n
- use 0 instead of disable macro
- modify OE judgment criteria
- add devm_regmap_init_mmio error message
- delete unused variable

v6: https://lore.kernel.org/all/20240406063413.3334639-1-qiujingbao.dlmu@gmail.com/

Changes since v5:
- delete the OE function because we plan to use the counter subsystem
  instead of capture, so there is no need to reuse this code.
- fix set polarity reverse error.

v5: https://lore.kernel.org/all/20240314100131.323540-1-qiujingbao.dlmu@gmail.com/

Changes since v4:
- drop filename
- fix macro
- optimize cv1800_pwm_set_polarity()
- optimize cv1800_pwm_set_oe()
- add comment for cv1800_pwm_set_oe()
- use ticks replace tem
- fix duty_cycle larger than period_val
- use devm_clk_rate_exclusive_get() replace
  clk_rate_exclusive_get()
- map linux polarity to register polarity 

v4: https://lore.kernel.org/all/20240304085933.1246964-1-qiujingbao.dlmu@gmail.com/

datasheet Link: https://github.com/milkv-duo/duo-files/blob/main/duo/datasheet/CV1800B-CV1801B-Preliminary-Datasheet-full-en.pdf
page 614

Changes since v3:
- use macro instead of npwm number
- add support for polarity feature
- add support for Output-Enable/OE feature

v3: https://lore.kernel.org/all/20240223082014.109385-1-qiujingbao.dlmu@gmail.com/

Changes since v2:
- use 0x08 instead of macro
- split if statements based on conditions
- in order to round up, first calculate the
  number of high-level cycles, then subtract
  it from the PERIOD to obtain the number of HLPERIOD
- use new pwmchip_alloc() API instead of old style

v2: https://lore.kernel.org/all/20240212121729.1086718-1-qiujingbao.dlmu@gmail.com/

Changes since v1:
- drop full stop from subject
- re-order maintainers and description
- pass checkpatch.pl --strict
- fix naming errors
- add "Limitations" section
- use a driver specific prefix for all defines
- using bool instead u32 in cv1800_pwm_enable
- check and set state->polarity
- use mul_u64_u64_div_u64
- use clk_rate_exclusive_get(), balance with clk_rate_exclusive_put()
- using macro definitions instead of shift operations
- remove shift operation on 0
- use priv replace cv_pwm
- hardcode npwm
- set atomic to true
- remove MODULE_ALIAS

v1: https://lore.kernel.org/all/20240207055856.672184-1-qiujingbao.dlmu@gmail.com/

Jingbao Qiu (2):
  dt-bindings: pwm: sophgo: add pwm for Sophgo CV1800 series SoC
  pwm: sophgo: add pwm support for Sophgo CV1800 SoC

 .../bindings/pwm/sophgo,cv1800-pwm.yaml       |  45 +++
 drivers/pwm/Kconfig                           |  10 +
 drivers/pwm/Makefile                          |   1 +
 drivers/pwm/pwm-cv1800.c                      | 293 ++++++++++++++++++
 4 files changed, 349 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
 create mode 100644 drivers/pwm/pwm-cv1800.c


base-commit: 32c44e1fa921aebf8a5ef9f778534a30aab39313
-- 
2.25.1

[PATCH v7 1/2] dt-bindings: pwm: sophgo: add pwm for Sophgo CV1800 series SoC

[Jingbao Qiu]

Add devicetree binding to describe the PWM for Sophgo CV1800 SoC.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
---
 .../bindings/pwm/sophgo,cv1800-pwm.yaml       | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml

diff --git a/Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml b/Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
new file mode 100644
index 000000000000..b5b819d780f1
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/sophgo,cv1800-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo CV1800 PWM controller
+
+maintainers:
+  - Jingbao Qiu <qiujingbao.dlmu@gmail.com>
+
+description:
+  The chip provides a set of four independent PWM channel outputs.
+
+allOf:
+  - $ref: pwm.yaml#
+
+properties:
+  compatible:
+    const: sophgo,cv1800-pwm
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 3
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    pwm0: pwm@3060000 {
+        compatible = "sophgo,cv1800-pwm";
+        reg = <0x3060000 0x1000>;
+        clocks = <&clk 60>;
+        #pwm-cells = <3>;
+    };
-- 
2.25.1

[PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Jingbao Qiu]

Implement the PWM driver for CV1800.

Signed-off-by: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
---
 drivers/pwm/Kconfig      |  10 ++
 drivers/pwm/Makefile     |   1 +
 drivers/pwm/pwm-cv1800.c | 293 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 304 insertions(+)
 create mode 100644 drivers/pwm/pwm-cv1800.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 1dd7921194f5..3869ca022aeb 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -182,6 +182,16 @@ config PWM_CROS_EC
 	  PWM driver for exposing a PWM attached to the ChromeOS Embedded
 	  Controller.
 
+config PWM_CV1800
+	tristate "Sophgo CV1800 PWM driver"
+	depends on ARCH_SOPHGO || COMPILE_TEST
+	help
+	  Generic PWM framework driver for the Sophgo CV1800 series
+	  SoCs.
+
+	  To compile this driver as a module, build the dependecies
+	  as modules, this will be called pwm-cv1800.
+
 config PWM_DWC_CORE
 	tristate
 	depends on HAS_IOMEM
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 90913519f11a..6295e2259efc 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_PWM_CLK)		+= pwm-clk.o
 obj-$(CONFIG_PWM_CLPS711X)	+= pwm-clps711x.o
 obj-$(CONFIG_PWM_CRC)		+= pwm-crc.o
 obj-$(CONFIG_PWM_CROS_EC)	+= pwm-cros-ec.o
+obj-$(CONFIG_PWM_CV1800)	+= pwm-cv1800.o
 obj-$(CONFIG_PWM_DWC_CORE)	+= pwm-dwc-core.o
 obj-$(CONFIG_PWM_DWC)		+= pwm-dwc.o
 obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
diff --git a/drivers/pwm/pwm-cv1800.c b/drivers/pwm/pwm-cv1800.c
new file mode 100644
index 000000000000..d487af637198
--- /dev/null
+++ b/drivers/pwm/pwm-cv1800.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Sophgo CV1800 PWM driver
+ * Author: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
+ *
+ * Limitations:
+ * - The hardware emits the inactive level when disabled.
+ * - This pwm device supports dynamic loading of PWM parameters. When PWMSTART
+ *   is written from 0 to 1, the register value (HLPERIODn, PERIODn) will be
+ *   temporarily stored inside the PWM. If you want to dynamically change the
+ *   waveform during PWM output, after writing the new value to HLPERIODn and
+ *   PERIODn, write 1 and then 0 to PWMUPDATE[n] to make the new value effective.
+ * - Supports up to Rate/2 output, and the lowest is about Rate/(2^30-1).
+ * - By setting HLPERIODn to 0, can produce 100% duty cycle.
+ * - This hardware could support inverted polarity. By default, the value of the
+ *   POLARITY register is 0x0. This means that HLPERIOD represents the number
+ *   of low level beats.
+ * - This hardware supports input mode and output mode, implemented through the
+ *   Output-Enable/OE register. However, this driver has not yet implemented
+ *   capture callback.
+ */
+
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+
+#define PWM_CV1800_HLPERIOD_BASE    0x00
+#define PWM_CV1800_PERIOD_BASE      0x04
+#define PWM_CV1800_POLARITY         0x40
+#define PWM_CV1800_START            0x44
+#define PWM_CV1800_DONE             0x48
+#define PWM_CV1800_UPDATE           0x4c
+#define PWM_CV1800_OE               0xd0
+
+#define PWM_CV1800_HLPERIOD(n)      (PWM_CV1800_HLPERIOD_BASE + ((n)*0x08))
+#define PWM_CV1800_PERIOD(n)        (PWM_CV1800_PERIOD_BASE + ((n)*0x08))
+
+#define PWM_CV1800_UPDATE_MASK(n)   BIT(n)
+#define PWM_CV1800_OE_MASK(n)       BIT(n)
+#define PWM_CV1800_START_MASK(n)    BIT(n)
+#define PWM_CV1800_POLARITY_MASK(n) BIT(n)
+
+#define PWM_CV1800_MAXPERIOD        0x3fffffff
+#define PWM_CV1800_MINPERIOD        2
+#define PWM_CV1800_CHANNELS         4
+#define PWM_CV1800_PERIOD_RESET     BIT(1)
+#define PWM_CV1800_HLPERIOD_RESET   BIT(0)
+#define PWM_CV1800_REG_ENABLE(n)    BIT(n)
+
+struct cv1800_pwm {
+	struct regmap *map;
+	struct clk *clk;
+	unsigned long clk_rate;
+};
+
+static inline struct cv1800_pwm *to_cv1800_pwm_dev(struct pwm_chip *chip)
+{
+	return pwmchip_get_drvdata(chip);
+}
+
+static const struct regmap_config cv1800_pwm_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static int cv1800_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
+			     bool enable)
+{
+	struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+	u32 pwm_enable, state;
+
+	regmap_read(priv->map, PWM_CV1800_START, &pwm_enable);
+	pwm_enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
+
+	/*
+	 * If the parameters are changed during runtime, Register needs
+	 * to be updated to take effect.
+	 */
+	if (pwm_enable && enable) {
+		regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
+				   PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
+				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+		regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
+				   PWM_CV1800_UPDATE_MASK(pwm->hwpwm), 0);
+	} else if (!pwm_enable && enable) {
+		regmap_update_bits(priv->map, PWM_CV1800_START,
+				   PWM_CV1800_START_MASK(pwm->hwpwm),
+				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+	} else if (pwm_enable && !enable) {
+		regmap_update_bits(priv->map, PWM_CV1800_START,
+				   PWM_CV1800_START_MASK(pwm->hwpwm), 0);
+	}
+
+	/* check and set OE/Output-Enable mode */
+	regmap_read(priv->map, PWM_CV1800_OE, &state);
+
+	if ((state & BIT(pwm->hwpwm)) && enable)
+		regmap_update_bits(priv->map, PWM_CV1800_OE,
+				   PWM_CV1800_OE_MASK(pwm->hwpwm),
+				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
+
+	return 0;
+}
+
+static void cv1800_pwm_set_polarity(struct pwm_chip *chip,
+				    struct pwm_device *pwm,
+				    enum pwm_polarity polarity)
+{
+	struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+	u32 config_polarity = 0;
+
+	if (pwm->state.enabled)
+		cv1800_pwm_enable(chip, pwm, !pwm->state.enabled);
+
+	if (polarity == PWM_POLARITY_NORMAL)
+		config_polarity = PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
+
+	regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
+			   PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
+			   config_polarity);
+}
+
+static int cv1800_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
+{
+	struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+	u32 period_val, hlperiod_val;
+	u64 ticks;
+
+	if (state->polarity != pwm->state.polarity)
+		cv1800_pwm_set_polarity(chip, pwm, state->polarity);
+
+	/*
+	 * This hardware use PERIOD and HLPERIOD registers to represent PWM waves.
+	 *
+	 * The meaning of PERIOD is how many clock cycles (from the clock source)
+	 * are used to represent PWM waves.
+	 * PERIOD = rate(MHz) / target(MHz)
+	 * PERIOD = period(ns) * rate(Hz) / NSEC_PER_SEC
+	 */
+	ticks = mul_u64_u64_div_u64(state->period, priv->clk_rate,
+				    NSEC_PER_SEC);
+	if (ticks < PWM_CV1800_MINPERIOD)
+		return -EINVAL;
+
+	if (ticks > PWM_CV1800_MAXPERIOD)
+		ticks = PWM_CV1800_MAXPERIOD;
+	period_val = (u32)ticks;
+
+	/*
+	 * After mapping, hlperiod represents the same polarity as duty.
+	 * HLPERIOD = rate(MHz) / duty(MHz)
+	 * HLPERIOD = duty(ns) * rate(Hz) / NSEC_PER_SEC
+	 */
+	ticks = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
+				    NSEC_PER_SEC);
+	if (ticks > period_val)
+		ticks = period_val;
+	hlperiod_val = (u32)ticks;
+
+	regmap_write(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), period_val);
+	regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
+
+	cv1800_pwm_enable(chip, pwm, state->enabled);
+
+	return 0;
+}
+
+static int cv1800_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_state *state)
+{
+	struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
+	u32 period_val, hlperiod_val;
+	u64 period_ns = 0, duty_ns = 0;
+	u32 enable = 0, polarity = 0;
+
+	regmap_read(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), &period_val);
+	regmap_read(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), &hlperiod_val);
+
+	if (period_val != PWM_CV1800_PERIOD_RESET ||
+	    hlperiod_val != PWM_CV1800_HLPERIOD_RESET) {
+		period_ns = DIV_ROUND_UP_ULL(period_val * NSEC_PER_SEC,
+					     priv->clk_rate);
+		duty_ns = DIV_ROUND_UP_ULL(hlperiod_val * NSEC_PER_SEC,
+					   priv->clk_rate);
+
+		regmap_read(priv->map, PWM_CV1800_START, &enable);
+		enable &= PWM_CV1800_START_MASK(pwm->hwpwm);
+
+		regmap_read(priv->map, PWM_CV1800_POLARITY, &polarity);
+		polarity &= PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
+	}
+
+	state->period = period_ns;
+	state->duty_cycle = duty_ns;
+	state->enabled = enable;
+
+	/*
+	 * To ensure that duty and hlperiod represent the same polarity
+	 * the following mapping needs to be completed.
+	 *
+	 * |----------|------------|------------|-----------|
+	 * |  Linux   |  register  |    duty    | register  |
+	 * | polarity |  polarity  |            | hlperiod  |
+	 * |----------|------------|------------|-----------|
+	 * |    1     |      0     | low level  | low level |
+	 * |----------|------------|------------|-----------|
+	 * |    0     |      1     | high level | high level|
+	 * |----------|------------|------------|-----------|
+	 */
+	state->polarity = polarity ? PWM_POLARITY_NORMAL :
+					   PWM_POLARITY_INVERSED;
+
+	return 0;
+}
+
+static const struct pwm_ops cv1800_pwm_ops = {
+	.apply = cv1800_pwm_apply,
+	.get_state = cv1800_pwm_get_state,
+};
+
+static int cv1800_pwm_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cv1800_pwm *priv;
+	struct pwm_chip *chip;
+	void __iomem *base;
+	int ret;
+
+	chip = devm_pwmchip_alloc(dev, PWM_CV1800_CHANNELS, sizeof(*priv));
+	if (!chip)
+		return PTR_ERR(chip);
+	priv = to_cv1800_pwm_dev(chip);
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	priv->map = devm_regmap_init_mmio(&pdev->dev, base,
+					  &cv1800_pwm_regmap_config);
+	if (IS_ERR(priv->map)) {
+		dev_err(dev, "Couldn't create PWM regmap\n");
+		return PTR_ERR(priv->map);
+	}
+
+	priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
+				     "clk not found\n");
+
+	ret = devm_clk_rate_exclusive_get(dev, priv->clk);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "failed to get exclusive rate\n");
+
+	priv->clk_rate = clk_get_rate(priv->clk);
+	if (!priv->clk_rate)
+		return dev_err_probe(&pdev->dev, -EINVAL,
+				     "Invalid clock rate: %lu\n",
+				     priv->clk_rate);
+
+	chip->ops = &cv1800_pwm_ops;
+
+	ret = devm_pwmchip_add(dev, chip);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
+
+	return 0;
+}
+
+static const struct of_device_id cv1800_pwm_dt_ids[] = {
+	{ .compatible = "sophgo,cv1800-pwm" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, cv1800_pwm_dt_ids);
+
+static struct platform_driver cv1800_pwm_driver = {
+	.probe = cv1800_pwm_probe,
+	.driver	= {
+		.name = "cv1800-pwm",
+		.of_match_table = cv1800_pwm_dt_ids,
+	},
+};
+module_platform_driver(cv1800_pwm_driver);
+
+MODULE_AUTHOR("Jingbao Qiu");
+MODULE_DESCRIPTION("Sophgo cv1800 PWM Driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1

Re: [PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Uwe Kleine-König]

[-- Attachment #1: Type: text/plain, Size: 9495 bytes --]

Hello,

On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
> [...]
> diff --git a/drivers/pwm/pwm-cv1800.c b/drivers/pwm/pwm-cv1800.c
> new file mode 100644
> index 000000000000..d487af637198
> --- /dev/null
> +++ b/drivers/pwm/pwm-cv1800.c
> @@ -0,0 +1,293 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Sophgo CV1800 PWM driver
> + * Author: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
> + *
> + * Limitations:
> + * - The hardware emits the inactive level when disabled.
> + * - This pwm device supports dynamic loading of PWM parameters. When PWMSTART
> + *   is written from 0 to 1, the register value (HLPERIODn, PERIODn) will be
> + *   temporarily stored inside the PWM. If you want to dynamically change the
> + *   waveform during PWM output, after writing the new value to HLPERIODn and
> + *   PERIODn, write 1 and then 0 to PWMUPDATE[n] to make the new value effective.

	To change polarity, the hardware has to be stopped though.

> + * - Supports up to Rate/2 output, and the lowest is about Rate/(2^30-1).

Rate = input clock rate?

> + * - By setting HLPERIODn to 0, can produce 100% duty cycle.
> + * - This hardware could support inverted polarity. By default, the value of the
> + *   POLARITY register is 0x0. This means that HLPERIOD represents the number
> + *   of low level beats.
> + * - This hardware supports input mode and output mode, implemented through the
> + *   Output-Enable/OE register. However, this driver has not yet implemented
> + *   capture callback.

> + */
> +
> +#include <linux/clk.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/regmap.h>
> +
> +#define PWM_CV1800_HLPERIOD_BASE    0x00
> +#define PWM_CV1800_PERIOD_BASE      0x04
> +#define PWM_CV1800_POLARITY         0x40
> +#define PWM_CV1800_START            0x44
> +#define PWM_CV1800_DONE             0x48
> +#define PWM_CV1800_UPDATE           0x4c
> +#define PWM_CV1800_OE               0xd0
> +
> +#define PWM_CV1800_HLPERIOD(n)      (PWM_CV1800_HLPERIOD_BASE + ((n)*0x08))
> +#define PWM_CV1800_PERIOD(n)        (PWM_CV1800_PERIOD_BASE + ((n)*0x08))

I suggest to drop the ..._BASE defines and hardcode the 0 and 4
respectively in the definition of PWM_CV1800_HLPERIOD and
PWM_CV1800_PERIOD. Also please use spaces around the multiplication *.

> +#define PWM_CV1800_UPDATE_MASK(n)   BIT(n)
> +#define PWM_CV1800_OE_MASK(n)       BIT(n)
> +#define PWM_CV1800_START_MASK(n)    BIT(n)
> +#define PWM_CV1800_POLARITY_MASK(n) BIT(n)
> +
> +#define PWM_CV1800_MAXPERIOD        0x3fffffff
> +#define PWM_CV1800_MINPERIOD        2
> +#define PWM_CV1800_CHANNELS         4
> +#define PWM_CV1800_PERIOD_RESET     BIT(1)

This is strange, the PWM_CV1800_PERIOD can be programmed with values >=
PWM_CV1800_MINPERIOD; if you program 2, you use period ==
PWM_CV1800_PERIOD_RESET.

> +#define PWM_CV1800_HLPERIOD_RESET   BIT(0)
> +#define PWM_CV1800_REG_ENABLE(n)    BIT(n)
> +
> +struct cv1800_pwm {
> +	struct regmap *map;
> +	struct clk *clk;
> +	unsigned long clk_rate;
> +};
> +
> +static inline struct cv1800_pwm *to_cv1800_pwm_dev(struct pwm_chip *chip)
> +{
> +	return pwmchip_get_drvdata(chip);
> +}
> +
> +static const struct regmap_config cv1800_pwm_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +};
> +
> +static int cv1800_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm,
> +			     bool enable)
> +{
> +	struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> +	u32 pwm_enable, state;
> +
> +	regmap_read(priv->map, PWM_CV1800_START, &pwm_enable);
> +	pwm_enable &= PWM_CV1800_START_MASK(pwm->hwpwm);

This value tells if the HW is enabled, right. Maybe rename the variable
to pwm_enabled (or pwm_is_enabled).

> +	/*
> +	 * If the parameters are changed during runtime, Register needs
> +	 * to be updated to take effect.
> +	 */
> +	if (pwm_enable && enable) {
> +		regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> +				   PWM_CV1800_UPDATE_MASK(pwm->hwpwm),
> +				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));

I would consider

		regmap_set_bits(priv->map, PWM_CV1800_UPDATE, BIT(pwm->hwpwm));

more readable.

> +		regmap_update_bits(priv->map, PWM_CV1800_UPDATE,
> +				   PWM_CV1800_UPDATE_MASK(pwm->hwpwm), 0);

Maybe add a comment about why you modify the same bit here twice.

> +	} else if (!pwm_enable && enable) {
> +		regmap_update_bits(priv->map, PWM_CV1800_START,
> +				   PWM_CV1800_START_MASK(pwm->hwpwm),
> +				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> +	} else if (pwm_enable && !enable) {
> +		regmap_update_bits(priv->map, PWM_CV1800_START,
> +				   PWM_CV1800_START_MASK(pwm->hwpwm), 0);
> +	}

The previous construct can be (IMO) simplified by doing:

	if (!enable) {
		if (pwm_enabled)
			regmap_clear_bits(...);
		return 0;
	}

	if (pwm_enabled) {
		...
	} else {
		...
	}

(This slightly changes semantics, but that's fine.)

> +
> +	/* check and set OE/Output-Enable mode */
> +	regmap_read(priv->map, PWM_CV1800_OE, &state);
> +
> +	if ((state & BIT(pwm->hwpwm)) && enable)
> +		regmap_update_bits(priv->map, PWM_CV1800_OE,
> +				   PWM_CV1800_OE_MASK(pwm->hwpwm),
> +				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));

This looks strange. If BIT(hwpwm) is already set, set it again?!
Also if you used the caching implemented in regmap, you don't need to
make this conditional.

> +	return 0;
> +}
> +
> +static void cv1800_pwm_set_polarity(struct pwm_chip *chip,
> +				    struct pwm_device *pwm,
> +				    enum pwm_polarity polarity)
> +{
> +	struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> +	u32 config_polarity = 0;
> +
> +	if (pwm->state.enabled)
> +		cv1800_pwm_enable(chip, pwm, !pwm->state.enabled);

Using false instead of !pwm->state.enabled would be more straight
forward.

> +	if (polarity == PWM_POLARITY_NORMAL)
> +		config_polarity = PWM_CV1800_POLARITY_MASK(pwm->hwpwm);
> +
> +	regmap_update_bits(priv->map, PWM_CV1800_POLARITY,
> +			   PWM_CV1800_POLARITY_MASK(pwm->hwpwm),
> +			   config_polarity);
> +}
> +
> +static int cv1800_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> +			    const struct pwm_state *state)
> +{
> +	struct cv1800_pwm *priv = to_cv1800_pwm_dev(chip);
> +	u32 period_val, hlperiod_val;
> +	u64 ticks;
> +
> +	if (state->polarity != pwm->state.polarity)
> +		cv1800_pwm_set_polarity(chip, pwm, state->polarity);
> +
> +	/*
> +	 * This hardware use PERIOD and HLPERIOD registers to represent PWM waves.
> +	 *
> +	 * The meaning of PERIOD is how many clock cycles (from the clock source)
> +	 * are used to represent PWM waves.
> +	 * PERIOD = rate(MHz) / target(MHz)
> +	 * PERIOD = period(ns) * rate(Hz) / NSEC_PER_SEC
> +	 */
> +	ticks = mul_u64_u64_div_u64(state->period, priv->clk_rate,
> +				    NSEC_PER_SEC);
> +	if (ticks < PWM_CV1800_MINPERIOD)
> +		return -EINVAL;

If you check this before configuring the period, it won't happen that
the hw state is modified before you notice you cannot fulfill the
requested state.

> +	if (ticks > PWM_CV1800_MAXPERIOD)
> +		ticks = PWM_CV1800_MAXPERIOD;
> +	period_val = (u32)ticks;

Maybe use period_ticks instead of period_val to have a consistent
naming.

> +
> +	/*
> +	 * After mapping, hlperiod represents the same polarity as duty.
> +	 * HLPERIOD = rate(MHz) / duty(MHz)
> +	 * HLPERIOD = duty(ns) * rate(Hz) / NSEC_PER_SEC
> +	 */

I don't understand that comment.

> +	ticks = mul_u64_u64_div_u64(state->duty_cycle, priv->clk_rate,
> +				    NSEC_PER_SEC);
> +	if (ticks > period_val)
> +		ticks = period_val;
> +	hlperiod_val = (u32)ticks;
> +
> +	regmap_write(priv->map, PWM_CV1800_PERIOD(pwm->hwpwm), period_val);
> +	regmap_write(priv->map, PWM_CV1800_HLPERIOD(pwm->hwpwm), hlperiod_val);
> +
> +	cv1800_pwm_enable(chip, pwm, state->enabled);
> +
> +	return 0;
> +}
> +
> [...]
> +static int cv1800_pwm_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct cv1800_pwm *priv;
> +	struct pwm_chip *chip;
> +	void __iomem *base;
> +	int ret;
> +
> +	chip = devm_pwmchip_alloc(dev, PWM_CV1800_CHANNELS, sizeof(*priv));

PWM_CV1800_CHANNELS is only used here. I'd prefer a plain 4 here. This
also makes this value easier to grep for.

> +	if (!chip)
> +		return PTR_ERR(chip);
> +	priv = to_cv1800_pwm_dev(chip);
> +
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	priv->map = devm_regmap_init_mmio(&pdev->dev, base,
> +					  &cv1800_pwm_regmap_config);
> +	if (IS_ERR(priv->map)) {
> +		dev_err(dev, "Couldn't create PWM regmap\n");
> +		return PTR_ERR(priv->map);

Use dev_err_probe please.

> +	}
> +
> +	priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
> +	if (IS_ERR(priv->clk))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
> +				     "clk not found\n");
> +
> +	ret = devm_clk_rate_exclusive_get(dev, priv->clk);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "failed to get exclusive rate\n");
> +
> +	priv->clk_rate = clk_get_rate(priv->clk);
> +	if (!priv->clk_rate)
> +		return dev_err_probe(&pdev->dev, -EINVAL,
> +				     "Invalid clock rate: %lu\n",
> +				     priv->clk_rate);

Please also error out if clk_rate > NSEC_PER_SEC, because otherwise you
might get overflows for the calculations in .apply().

> +
> +	chip->ops = &cv1800_pwm_ops;
> +
> +	ret = devm_pwmchip_add(dev, chip);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
> +
> +	return 0;
> +}
> [...]

Best regards
Uwe

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Re: [PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Thomas Bonnefille]

Hello,

On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote:
> On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
>> [...]
>> +	if ((state & BIT(pwm->hwpwm)) && enable)
>> +		regmap_update_bits(priv->map, PWM_CV1800_OE,
>> +				   PWM_CV1800_OE_MASK(pwm->hwpwm),
>> +				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
>
> This looks strange. If BIT(hwpwm) is already set, set it again?!
> Also if you used the caching implemented in regmap, you don't need to
> make this conditional.
>

I was testing the series and noticed indeed an issue in this driver at
those lines. If PWM_CV1800_OE isn't set by something else than the
kernel it will never be set and so, there will never be a PWM outputted.

Using :
    if (!(state & BIT(pwm->hwpwm)) && enable)
Solved the issue but as Uwe said you can probably rely on regmap caching
to avoid this condition.

>
> ...
> 

Do you plan on sending a new iteration some day ? I may have some time
to continue the upstreaming process if you need to.

Thank you for this series !
Thomas

Re: [PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Jingbao Qiu]

On Sun, Apr 6, 2025 at 8:16 AM Thomas Bonnefille
<thomas.bonnefille@bootlin.com> wrote:
>
> Hello,
>
> On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote:
> > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
> >> [...]
> >> +    if ((state & BIT(pwm->hwpwm)) && enable)
> >> +            regmap_update_bits(priv->map, PWM_CV1800_OE,
> >> +                               PWM_CV1800_OE_MASK(pwm->hwpwm),
> >> +                               PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> >
> > This looks strange. If BIT(hwpwm) is already set, set it again?!
> > Also if you used the caching implemented in regmap, you don't need to
> > make this conditional.
> >
>
> I was testing the series and noticed indeed an issue in this driver at
> those lines. If PWM_CV1800_OE isn't set by something else than the
> kernel it will never be set and so, there will never be a PWM outputted.
>
> Using :
>     if (!(state & BIT(pwm->hwpwm)) && enable)
> Solved the issue but as Uwe said you can probably rely on regmap caching
> to avoid this condition.
>
> >
> > ...
> >
>
> Do you plan on sending a new iteration some day ? I may have some time
> to continue the upstreaming process if you need to.
>
I am so happy you can continue finish this patch.

Best regards
Jingbao Qiu

Re: [PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Chen Wang]

On 2025/4/7 13:38, Jingbao Qiu wrote:
> On Sun, Apr 6, 2025 at 8:16 AM Thomas Bonnefille
> <thomas.bonnefille@bootlin.com> wrote:
>> Hello,
>>
>> On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote:
>>> On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
>>>> [...]
>>>> +    if ((state & BIT(pwm->hwpwm)) && enable)
>>>> +            regmap_update_bits(priv->map, PWM_CV1800_OE,
>>>> +                               PWM_CV1800_OE_MASK(pwm->hwpwm),
>>>> +                               PWM_CV1800_REG_ENABLE(pwm->hwpwm));
>>> This looks strange. If BIT(hwpwm) is already set, set it again?!
>>> Also if you used the caching implemented in regmap, you don't need to
>>> make this conditional.
>>>
>> I was testing the series and noticed indeed an issue in this driver at
>> those lines. If PWM_CV1800_OE isn't set by something else than the
>> kernel it will never be set and so, there will never be a PWM outputted.
>>
>> Using :
>>      if (!(state & BIT(pwm->hwpwm)) && enable)
>> Solved the issue but as Uwe said you can probably rely on regmap caching
>> to avoid this condition.
>>
>>> ...
>>>
>> Do you plan on sending a new iteration some day ? I may have some time
>> to continue the upstreaming process if you need to.
>>
> I am so happy you can continue finish this patch.
>
> Best regards
> Jingbao Qiu

Thank you Thomas, I updated info on https://github.com/sophgo/linux/wiki.

Thank you Jingbao too for your good job done.

Chen

Re: [PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Inochi Amaoto]

On Sun, Apr 06, 2025 at 02:16:41AM +0200, Thomas Bonnefille wrote:
> Hello,
> 
> On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote:
> > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
> >> [...]
> >> +	if ((state & BIT(pwm->hwpwm)) && enable)
> >> +		regmap_update_bits(priv->map, PWM_CV1800_OE,
> >> +				   PWM_CV1800_OE_MASK(pwm->hwpwm),
> >> +				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> >
> > This looks strange. If BIT(hwpwm) is already set, set it again?!
> > Also if you used the caching implemented in regmap, you don't need to
> > make this conditional.
> >
> 
> I was testing the series and noticed indeed an issue in this driver at
> those lines. If PWM_CV1800_OE isn't set by something else than the
> kernel it will never be set and so, there will never be a PWM outputted.
> 
> Using :
>     if (!(state & BIT(pwm->hwpwm)) && enable)
> Solved the issue but as Uwe said you can probably rely on regmap caching
> to avoid this condition.
> 
> >
> > ...
> > 
> 
> Do you plan on sending a new iteration some day ? I may have some time
> to continue the upstreaming process if you need to.
> 
> Thank you for this series !
> Thomas

I suggest checking existing spi-sg2044-nor driver, which may reduce your
work for upstreaming.

Regards,
Inochi

Re: [PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Thomas Bonnefille]

On Mon Apr 7, 2025 at 9:21 AM CEST, Inochi Amaoto wrote:
> On Sun, Apr 06, 2025 at 02:16:41AM +0200, Thomas Bonnefille wrote:
>> Hello,
>> 
>> On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote:
>> > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
>> >> [...]
>> >> +	if ((state & BIT(pwm->hwpwm)) && enable)
>> >> +		regmap_update_bits(priv->map, PWM_CV1800_OE,
>> >> +				   PWM_CV1800_OE_MASK(pwm->hwpwm),
>> >> +				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
>> >
>> > This looks strange. If BIT(hwpwm) is already set, set it again?!
>> > Also if you used the caching implemented in regmap, you don't need to
>> > make this conditional.
>> >
>> 
>> I was testing the series and noticed indeed an issue in this driver at
>> those lines. If PWM_CV1800_OE isn't set by something else than the
>> kernel it will never be set and so, there will never be a PWM outputted.
>> 
>> Using :
>>     if (!(state & BIT(pwm->hwpwm)) && enable)
>> Solved the issue but as Uwe said you can probably rely on regmap caching
>> to avoid this condition.
>> 
>> >
>> > ...
>> > 
>> 
>> Do you plan on sending a new iteration some day ? I may have some time
>> to continue the upstreaming process if you need to.
>> 
>> Thank you for this series !
>> Thomas
>
> I suggest checking existing spi-sg2044-nor driver, which may reduce your
> work for upstreaming.
>
> Regards,
> Inochi

Hello Inochi,

Thank you very much, however even after reading it I can't see the link
between the SPI NOR controller driver of the SG2044 and the PWM driver
for the CV18XX series ?

Regards,
Thomas

Re: [PATCH v7 2/2] pwm: sophgo: add pwm support for Sophgo CV1800 SoC

[Inochi Amaoto]

On Tue, Apr 08, 2025 at 09:54:27AM +0200, Thomas Bonnefille wrote:
> On Mon Apr 7, 2025 at 9:21 AM CEST, Inochi Amaoto wrote:
> > On Sun, Apr 06, 2025 at 02:16:41AM +0200, Thomas Bonnefille wrote:
> >> Hello,
> >> 
> >> On Sat Jun 1, 2024 at 1:53 PM CEST, Uwe Kleine-König wrote:
> >> > On Wed, May 01, 2024 at 04:32:42PM +0800, Jingbao Qiu wrote:
> >> >> [...]
> >> >> +	if ((state & BIT(pwm->hwpwm)) && enable)
> >> >> +		regmap_update_bits(priv->map, PWM_CV1800_OE,
> >> >> +				   PWM_CV1800_OE_MASK(pwm->hwpwm),
> >> >> +				   PWM_CV1800_REG_ENABLE(pwm->hwpwm));
> >> >
> >> > This looks strange. If BIT(hwpwm) is already set, set it again?!
> >> > Also if you used the caching implemented in regmap, you don't need to
> >> > make this conditional.
> >> >
> >> 
> >> I was testing the series and noticed indeed an issue in this driver at
> >> those lines. If PWM_CV1800_OE isn't set by something else than the
> >> kernel it will never be set and so, there will never be a PWM outputted.
> >> 
> >> Using :
> >>     if (!(state & BIT(pwm->hwpwm)) && enable)
> >> Solved the issue but as Uwe said you can probably rely on regmap caching
> >> to avoid this condition.
> >> 
> >> >
> >> > ...
> >> > 
> >> 
> >> Do you plan on sending a new iteration some day ? I may have some time
> >> to continue the upstreaming process if you need to.
> >> 
> >> Thank you for this series !
> >> Thomas
> >
> > I suggest checking existing spi-sg2044-nor driver, which may reduce your
> > work for upstreaming.
> >
> > Regards,
> > Inochi
> 
> Hello Inochi,
> 
> Thank you very much, however even after reading it I can't see the link
> between the SPI NOR controller driver of the SG2044 and the PWM driver
> for the CV18XX series ?
> 
> Regards,
> Thomas

I am sorry, I mistake this as the spi-nor one. You may want to check
the SG2044 pwm driver, which should be similiar. You could find it at 
https://lore.kernel.org/all/20250407072056.8629-1-looong.bin@gmail.com/

Regards,
Inochi

Re: [PATCH v7 0/2] riscv: pwm: sophgo: add pwm support for CV1800

[Chen Wang]

Hi, Jingbao,

This patchset should also be sent to the linux-riscv mailinglist.

On 2024/5/1 16:32, Jingbao Qiu wrote:
> The Sophgo CV1800 chip provides a set of four independent
> PWM channel outputs.
> This series adds PWM controller support for Sophgo cv1800.
>
> Changes since v6:
> - add detailed Limitations
> - using BIT(n) instead BIT(0) << n
> - use 0 instead of disable macro
> - modify OE judgment criteria
> - add devm_regmap_init_mmio error message
> - delete unused variable
>
> v6: https://lore.kernel.org/all/20240406063413.3334639-1-qiujingbao.dlmu@gmail.com/
>
> Changes since v5:
> - delete the OE function because we plan to use the counter subsystem
>    instead of capture, so there is no need to reuse this code.
> - fix set polarity reverse error.
>
> v5: https://lore.kernel.org/all/20240314100131.323540-1-qiujingbao.dlmu@gmail.com/
>
> Changes since v4:
> - drop filename
> - fix macro
> - optimize cv1800_pwm_set_polarity()
> - optimize cv1800_pwm_set_oe()
> - add comment for cv1800_pwm_set_oe()
> - use ticks replace tem
> - fix duty_cycle larger than period_val
> - use devm_clk_rate_exclusive_get() replace
>    clk_rate_exclusive_get()
> - map linux polarity to register polarity
>
> v4: https://lore.kernel.org/all/20240304085933.1246964-1-qiujingbao.dlmu@gmail.com/
>
> datasheet Link: https://github.com/milkv-duo/duo-files/blob/main/duo/datasheet/CV1800B-CV1801B-Preliminary-Datasheet-full-en.pdf
> page 614
>
> Changes since v3:
> - use macro instead of npwm number
> - add support for polarity feature
> - add support for Output-Enable/OE feature
>
> v3: https://lore.kernel.org/all/20240223082014.109385-1-qiujingbao.dlmu@gmail.com/
>
> Changes since v2:
> - use 0x08 instead of macro
> - split if statements based on conditions
> - in order to round up, first calculate the
>    number of high-level cycles, then subtract
>    it from the PERIOD to obtain the number of HLPERIOD
> - use new pwmchip_alloc() API instead of old style
>
> v2: https://lore.kernel.org/all/20240212121729.1086718-1-qiujingbao.dlmu@gmail.com/
>
> Changes since v1:
> - drop full stop from subject
> - re-order maintainers and description
> - pass checkpatch.pl --strict
> - fix naming errors
> - add "Limitations" section
> - use a driver specific prefix for all defines
> - using bool instead u32 in cv1800_pwm_enable
> - check and set state->polarity
> - use mul_u64_u64_div_u64
> - use clk_rate_exclusive_get(), balance with clk_rate_exclusive_put()
> - using macro definitions instead of shift operations
> - remove shift operation on 0
> - use priv replace cv_pwm
> - hardcode npwm
> - set atomic to true
> - remove MODULE_ALIAS
>
> v1: https://lore.kernel.org/all/20240207055856.672184-1-qiujingbao.dlmu@gmail.com/
>
> Jingbao Qiu (2):
>    dt-bindings: pwm: sophgo: add pwm for Sophgo CV1800 series SoC
>    pwm: sophgo: add pwm support for Sophgo CV1800 SoC
>
>   .../bindings/pwm/sophgo,cv1800-pwm.yaml       |  45 +++
>   drivers/pwm/Kconfig                           |  10 +
>   drivers/pwm/Makefile                          |   1 +
>   drivers/pwm/pwm-cv1800.c                      | 293 ++++++++++++++++++
>   4 files changed, 349 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
>   create mode 100644 drivers/pwm/pwm-cv1800.c
>
>
> base-commit: 32c44e1fa921aebf8a5ef9f778534a30aab39313

Re: [PATCH v7 0/2] riscv: pwm: sophgo: add pwm support for CV1800

[Jingbao Qiu]

On Fri, May 3, 2024 at 9:47 AM Chen Wang <unicorn_wang@outlook.com> wrote:
>
> Hi, Jingbao,
>
> This patchset should also be sent to the linux-riscv mailinglist.

I will do that.

>
> On 2024/5/1 16:32, Jingbao Qiu wrote:
> > The Sophgo CV1800 chip provides a set of four independent
> > PWM channel outputs.
> > This series adds PWM controller support for Sophgo cv1800.
> >
> > Changes since v6:
> > - add detailed Limitations
> > - using BIT(n) instead BIT(0) << n
> > - use 0 instead of disable macro
> > - modify OE judgment criteria
> > - add devm_regmap_init_mmio error message
> > - delete unused variable
> >
> > v6: https://lore.kernel.org/all/20240406063413.3334639-1-qiujingbao.dlmu@gmail.com/
> >
> > Changes since v5:
> > - delete the OE function because we plan to use the counter subsystem
> >    instead of capture, so there is no need to reuse this code.
> > - fix set polarity reverse error.
> >
> > v5: https://lore.kernel.org/all/20240314100131.323540-1-qiujingbao.dlmu@gmail.com/
> >
> > Changes since v4:
> > - drop filename
> > - fix macro
> > - optimize cv1800_pwm_set_polarity()
> > - optimize cv1800_pwm_set_oe()
> > - add comment for cv1800_pwm_set_oe()
> > - use ticks replace tem
> > - fix duty_cycle larger than period_val
> > - use devm_clk_rate_exclusive_get() replace
> >    clk_rate_exclusive_get()
> > - map linux polarity to register polarity
> >
> > v4: https://lore.kernel.org/all/20240304085933.1246964-1-qiujingbao.dlmu@gmail.com/
> >
> > datasheet Link: https://github.com/milkv-duo/duo-files/blob/main/duo/datasheet/CV1800B-CV1801B-Preliminary-Datasheet-full-en.pdf
> > page 614
> >
> > Changes since v3:
> > - use macro instead of npwm number
> > - add support for polarity feature
> > - add support for Output-Enable/OE feature
> >
> > v3: https://lore.kernel.org/all/20240223082014.109385-1-qiujingbao.dlmu@gmail.com/
> >
> > Changes since v2:
> > - use 0x08 instead of macro
> > - split if statements based on conditions
> > - in order to round up, first calculate the
> >    number of high-level cycles, then subtract
> >    it from the PERIOD to obtain the number of HLPERIOD
> > - use new pwmchip_alloc() API instead of old style
> >
> > v2: https://lore.kernel.org/all/20240212121729.1086718-1-qiujingbao.dlmu@gmail.com/
> >
> > Changes since v1:
> > - drop full stop from subject
> > - re-order maintainers and description
> > - pass checkpatch.pl --strict
> > - fix naming errors
> > - add "Limitations" section
> > - use a driver specific prefix for all defines
> > - using bool instead u32 in cv1800_pwm_enable
> > - check and set state->polarity
> > - use mul_u64_u64_div_u64
> > - use clk_rate_exclusive_get(), balance with clk_rate_exclusive_put()
> > - using macro definitions instead of shift operations
> > - remove shift operation on 0
> > - use priv replace cv_pwm
> > - hardcode npwm
> > - set atomic to true
> > - remove MODULE_ALIAS
> >
> > v1: https://lore.kernel.org/all/20240207055856.672184-1-qiujingbao.dlmu@gmail.com/
> >
> > Jingbao Qiu (2):
> >    dt-bindings: pwm: sophgo: add pwm for Sophgo CV1800 series SoC
> >    pwm: sophgo: add pwm support for Sophgo CV1800 SoC
> >
> >   .../bindings/pwm/sophgo,cv1800-pwm.yaml       |  45 +++
> >   drivers/pwm/Kconfig                           |  10 +
> >   drivers/pwm/Makefile                          |   1 +
> >   drivers/pwm/pwm-cv1800.c                      | 293 ++++++++++++++++++
> >   4 files changed, 349 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
> >   create mode 100644 drivers/pwm/pwm-cv1800.c
> >
> >
> > base-commit: 32c44e1fa921aebf8a5ef9f778534a30aab39313

Best regards
Jingbao Qiu