15 files changed, 298 insertions, 52 deletions
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 0915c1e7df16..4731d5b90d7e 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -567,7 +567,7 @@ config PWM_SIFIVE
 	tristate "SiFive PWM support"
 	depends on OF
 	depends on COMMON_CLK && HAS_IOMEM
-	depends on RISCV || COMPILE_TEST
+	depends on ARCH_SIFIVE || COMPILE_TEST
 	help
 	  Generic PWM framework driver for SiFive SoCs.
 
@@ -584,6 +584,16 @@ config PWM_SL28CPLD
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-sl28cpld.
 
+config PWM_SOPHGO_SG2042
+	tristate "Sophgo SG2042 PWM support"
+	depends on ARCH_SOPHGO || COMPILE_TEST
+	help
+	  PWM driver for the PWM controller on Sophgo SG2042 SoC. The PWM
+	  controller supports outputing 4 channels of PWM waveforms.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm_sophgo_sg2042.
+
 config PWM_SPEAR
 	tristate "STMicroelectronics SPEAr PWM support"
 	depends on PLAT_SPEAR || COMPILE_TEST
@@ -636,7 +646,7 @@ config PWM_STM32_LP
 	  will be called pwm-stm32-lp.
 
 config PWM_STMPE
-	bool "STMPE expander PWM export"
+	tristate "STMPE expander PWM export"
 	depends on MFD_STMPE
 	help
 	  This enables support for the PWMs found in the STMPE I/O
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 9081e0c0e9e0..539e0def3f82 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_PWM_RZ_MTU3)	+= pwm-rz-mtu3.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
 obj-$(CONFIG_PWM_SIFIVE)	+= pwm-sifive.o
 obj-$(CONFIG_PWM_SL28CPLD)	+= pwm-sl28cpld.o
+obj-$(CONFIG_PWM_SOPHGO_SG2042)	+= pwm-sophgo-sg2042.o
 obj-$(CONFIG_PWM_SPEAR)		+= pwm-spear.o
 obj-$(CONFIG_PWM_SPRD)		+= pwm-sprd.o
 obj-$(CONFIG_PWM_STI)		+= pwm-sti.o
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index ccd54c089bab..0387bd838487 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -322,7 +322,7 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
 	const struct pwm_ops *ops = chip->ops;
 	char wfhw[WFHWSIZE];
 	struct pwm_waveform wf_rounded;
-	int err;
+	int err, ret_tohw;
 
 	BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
 
@@ -332,16 +332,16 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
 	if (!pwm_wf_valid(wf))
 		return -EINVAL;
 
-	err = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw);
-	if (err)
-		return err;
+	ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw);
+	if (ret_tohw < 0)
+		return ret_tohw;
 
 	if ((IS_ENABLED(CONFIG_PWM_DEBUG) || exact) && wf->period_length_ns) {
 		err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded);
 		if (err)
 			return err;
 
-		if (IS_ENABLED(CONFIG_PWM_DEBUG) && !pwm_check_rounding(wf, &wf_rounded))
+		if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_tohw == 0 && !pwm_check_rounding(wf, &wf_rounded))
 			dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
 				wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
 				wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
@@ -382,7 +382,8 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
 				wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns,
 				wf_set.duty_length_ns, wf_set.period_length_ns, wf_set.duty_offset_ns);
 	}
-	return 0;
+
+	return ret_tohw;
 }
 
 /**
@@ -1000,11 +1001,27 @@ of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *arg
 }
 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
 
+/*
+ * This callback is used for PXA PWM chips that only have a single PWM line.
+ * For such chips you could argue that passing the line number (i.e. the first
+ * parameter in the common case) is useless as it's always zero. So compared to
+ * the default xlate function of_pwm_xlate_with_flags() the first parameter is
+ * the default period and the second are flags.
+ *
+ * Note that if #pwm-cells = <3>, the semantic is the same as for
+ * of_pwm_xlate_with_flags() to allow converting the affected driver to
+ * #pwm-cells = <3> without breaking the legacy binding.
+ *
+ * Don't use for new drivers.
+ */
 struct pwm_device *
 of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
 {
 	struct pwm_device *pwm;
 
+	if (args->args_count >= 3)
+		return of_pwm_xlate_with_flags(chip, args);
+
 	pwm = pwm_request_from_chip(chip, 0, NULL);
 	if (IS_ERR(pwm))
 		return pwm;
@@ -1716,8 +1733,7 @@ static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
 			return ERR_PTR(index);
 	}
 
-	err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
-					 &args);
+	err = of_parse_phandle_with_args_map(np, "pwms", "pwm", index, &args);
 	if (err) {
 		pr_err("%s(): can't parse \"pwms\" property\n", __func__);
 		return ERR_PTR(err);
diff --git a/drivers/pwm/pwm-axi-pwmgen.c b/drivers/pwm/pwm-axi-pwmgen.c
index 4259a0db9ff4..4337c8f5acf0 100644
--- a/drivers/pwm/pwm-axi-pwmgen.c
+++ b/drivers/pwm/pwm-axi-pwmgen.c
@@ -75,6 +75,7 @@ static int axi_pwmgen_round_waveform_tohw(struct pwm_chip *chip,
 {
 	struct axi_pwmgen_waveform *wfhw = _wfhw;
 	struct axi_pwmgen_ddata *ddata = axi_pwmgen_ddata_from_chip(chip);
+	int ret = 0;
 
 	if (wf->period_length_ns == 0) {
 		*wfhw = (struct axi_pwmgen_waveform){
@@ -91,12 +92,15 @@ static int axi_pwmgen_round_waveform_tohw(struct pwm_chip *chip,
 		if (wfhw->period_cnt == 0) {
 			/*
 			 * The specified period is too short for the hardware.
-			 * Let's round .duty_cycle down to 0 to get a (somewhat)
-			 * valid result.
+			 * So round up .period_cnt to 1 (i.e. the smallest
+			 * possible period). With .duty_cycle and .duty_offset
+			 * being less than or equal to .period, their rounded
+			 * value must be 0.
 			 */
 			wfhw->period_cnt = 1;
 			wfhw->duty_cycle_cnt = 0;
 			wfhw->duty_offset_cnt = 0;
+			ret = 1;
 		} else {
 			wfhw->duty_cycle_cnt = min_t(u64,
 						     mul_u64_u32_div(wf->duty_length_ns, ddata->clk_rate_hz, NSEC_PER_SEC),
@@ -111,7 +115,7 @@ static int axi_pwmgen_round_waveform_tohw(struct pwm_chip *chip,
 		pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
 		ddata->clk_rate_hz, wfhw->period_cnt, wfhw->duty_cycle_cnt, wfhw->duty_offset_cnt);
 
-	return 0;
+	return ret;
 }
 
 static int axi_pwmgen_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,
diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index c950e1dbd2b8..04559a9de718 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -98,7 +98,7 @@ static int clps711x_pwm_probe(struct platform_device *pdev)
 	return devm_pwmchip_add(&pdev->dev, chip);
 }
 
-static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
+static const struct of_device_id clps711x_pwm_dt_ids[] = {
 	{ .compatible = "cirrus,ep7209-pwm", },
 	{ }
 };
@@ -107,7 +107,7 @@ MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
 static struct platform_driver clps711x_pwm_driver = {
 	.driver = {
 		.name = "clps711x-pwm",
-		.of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
+		.of_match_table = clps711x_pwm_dt_ids,
 	},
 	.probe = clps711x_pwm_probe,
 };
diff --git a/drivers/pwm/pwm-fsl-ftm.c b/drivers/pwm/pwm-fsl-ftm.c
index 2510c10ca473..c45a5fca4cbb 100644
--- a/drivers/pwm/pwm-fsl-ftm.c
+++ b/drivers/pwm/pwm-fsl-ftm.c
@@ -118,6 +118,9 @@ static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
 	unsigned long long exval;
 
 	rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
+	if (rate >> fpc->period.clk_ps == 0)
+		return 0;
+
 	exval = ticks;
 	exval *= 1000000000UL;
 	do_div(exval, rate >> fpc->period.clk_ps);
@@ -190,6 +193,9 @@ static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
 	unsigned int period = fpc->period.mod_period + 1;
 	unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);
 
+	if (!period_ns)
+		return 0;
+
 	duty = (unsigned long long)duty_ns * period;
 	do_div(duty, period_ns);
 
diff --git a/drivers/pwm/pwm-gpio.c b/drivers/pwm/pwm-gpio.c
index 9f8884ac7504..5f4edeb394a9 100644
--- a/drivers/pwm/pwm-gpio.c
+++ b/drivers/pwm/pwm-gpio.c
@@ -207,13 +207,12 @@ static int pwm_gpio_probe(struct platform_device *pdev)
 	chip->ops = &pwm_gpio_ops;
 	chip->atomic = true;
 
-	hrtimer_init(&gpwm->gpio_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hrtimer_setup(&gpwm->gpio_timer, pwm_gpio_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+
 	ret = devm_add_action_or_reset(dev, pwm_gpio_disable_hrtimer, gpwm);
 	if (ret)
 		return ret;
 
-	gpwm->gpio_timer.function = pwm_gpio_timer;
-
 	ret = pwmchip_add(chip);
 	if (ret < 0)
 		return dev_err_probe(dev, ret, "could not add pwmchip\n");
diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 3b99feb3bb49..c976ff1c8ed9 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -10,6 +10,8 @@
  * Author: Alan Cox <alan@linux.intel.com>
  */
 
+#define DEFAULT_SYMBOL_NAMESPACE "PWM_LPSS"
+
 #include <linux/bits.h>
 #include <linux/delay.h>
 #include <linux/io.h>
@@ -17,10 +19,9 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/pwm.h>
 #include <linux/time.h>
 
-#define DEFAULT_SYMBOL_NAMESPACE "PWM_LPSS"
-
 #include "pwm-lpss.h"
 
 #define PWM				0x00000000
diff --git a/drivers/pwm/pwm-lpss.h b/drivers/pwm/pwm-lpss.h
index b5267ab5193b..60792181401e 100644
--- a/drivers/pwm/pwm-lpss.h
+++ b/drivers/pwm/pwm-lpss.h
@@ -10,7 +10,6 @@
 #ifndef __PWM_LPSS_H
 #define __PWM_LPSS_H
 
-#include <linux/pwm.h>
 #include <linux/types.h>
 
 #include <linux/platform_data/x86/pwm-lpss.h>
diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index 01dfa0fab80a..7eaab5831499 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -121,21 +121,25 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
 	u32 clkdiv = 0, cnt_period, cnt_duty, reg_width = PWMDWIDTH,
 	    reg_thres = PWMTHRES;
+	unsigned long clk_rate;
 	u64 resolution;
 	int ret;
 
 	ret = pwm_mediatek_clk_enable(chip, pwm);
-
 	if (ret < 0)
 		return ret;
 
+	clk_rate = clk_get_rate(pc->clk_pwms[pwm->hwpwm]);
+	if (!clk_rate)
+		return -EINVAL;
+
 	/* Make sure we use the bus clock and not the 26MHz clock */
 	if (pc->soc->has_ck_26m_sel)
 		writel(0, pc->regs + PWM_CK_26M_SEL);
 
 	/* Using resolution in picosecond gets accuracy higher */
 	resolution = (u64)NSEC_PER_SEC * 1000;
-	do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm]));
+	do_div(resolution, clk_rate);
 
 	cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution);
 	while (cnt_period > 8191) {
diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c
index 1298b29183e5..5162f3991644 100644
--- a/drivers/pwm/pwm-pca9685.c
+++ b/drivers/pwm/pwm-pca9685.c
@@ -8,7 +8,6 @@
  * based on the pwm-twl-led.c driver
  */
 
-#include <linux/acpi.h>
 #include <linux/gpio/driver.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
@@ -639,21 +638,17 @@ static const struct i2c_device_id pca9685_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 
-#ifdef CONFIG_ACPI
 static const struct acpi_device_id pca9685_acpi_ids[] = {
 	{ "INT3492", 0 },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
-#endif
 
-#ifdef CONFIG_OF
 static const struct of_device_id pca9685_dt_ids[] = {
 	{ .compatible = "nxp,pca9685-pwm", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
-#endif
 
 static const struct dev_pm_ops pca9685_pwm_pm = {
 	SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
@@ -663,8 +658,8 @@ static const struct dev_pm_ops pca9685_pwm_pm = {
 static struct i2c_driver pca9685_i2c_driver = {
 	.driver = {
 		.name = "pca9685-pwm",
-		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
-		.of_match_table = of_match_ptr(pca9685_dt_ids),
+		.acpi_match_table = pca9685_acpi_ids,
+		.of_match_table = pca9685_dt_ids,
 		.pm = &pca9685_pwm_pm,
 	},
 	.probe = pca9685_pwm_probe,
diff --git a/drivers/pwm/pwm-rcar.c b/drivers/pwm/pwm-rcar.c
index 2261789cc27d..578dbdd2d5a7 100644
--- a/drivers/pwm/pwm-rcar.c
+++ b/drivers/pwm/pwm-rcar.c
@@ -8,6 +8,7 @@
  * - The hardware cannot generate a 0% duty cycle.
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
@@ -102,23 +103,24 @@ static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
 	rcar_pwm_write(rp, value, RCAR_PWMCR);
 }
 
-static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
-				int period_ns)
+static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, u64 duty_ns,
+				u64 period_ns)
 {
-	unsigned long long one_cycle, tmp;	/* 0.01 nanoseconds */
+	unsigned long long tmp;
 	unsigned long clk_rate = clk_get_rate(rp->clk);
 	u32 cyc, ph;
 
-	one_cycle = NSEC_PER_SEC * 100ULL << div;
-	do_div(one_cycle, clk_rate);
+	/* div <= 24 == RCAR_PWM_MAX_DIVISION, so the shift doesn't overflow. */
+	tmp = mul_u64_u64_div_u64(period_ns, clk_rate, (u64)NSEC_PER_SEC << div);
+	if (tmp > FIELD_MAX(RCAR_PWMCNT_CYC0_MASK))
+		tmp = FIELD_MAX(RCAR_PWMCNT_CYC0_MASK);
 
-	tmp = period_ns * 100ULL;
-	do_div(tmp, one_cycle);
-	cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;
+	cyc = FIELD_PREP(RCAR_PWMCNT_CYC0_MASK, tmp);
 
-	tmp = duty_ns * 100ULL;
-	do_div(tmp, one_cycle);
-	ph = tmp & RCAR_PWMCNT_PH0_MASK;
+	tmp = mul_u64_u64_div_u64(duty_ns, clk_rate, (u64)NSEC_PER_SEC << div);
+	if (tmp > FIELD_MAX(RCAR_PWMCNT_PH0_MASK))
+		tmp = FIELD_MAX(RCAR_PWMCNT_PH0_MASK);
+	ph = FIELD_PREP(RCAR_PWMCNT_PH0_MASK, tmp);
 
 	/* Avoid prohibited setting */
 	if (cyc == 0 || ph == 0)
diff --git a/drivers/pwm/pwm-sophgo-sg2042.c b/drivers/pwm/pwm-sophgo-sg2042.c
new file mode 100644
index 000000000000..ff4639d849ce
--- /dev/null
+++ b/drivers/pwm/pwm-sophgo-sg2042.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sophgo SG2042 PWM Controller Driver
+ *
+ * Copyright (C) 2024 Sophgo Technology Inc.
+ * Copyright (C) 2024 Chen Wang <unicorn_wang@outlook.com>
+ *
+ * Limitations:
+ * - After reset, the output of the PWM channel is always high.
+ *   The value of HLPERIOD/PERIOD is 0.
+ * - When HLPERIOD or PERIOD is reconfigured, PWM will start to
+ *   output waveforms with the new configuration after completing
+ *   the running period.
+ * - When PERIOD and HLPERIOD is set to 0, the PWM wave output will
+ *   be stopped and the output is pulled to high.
+ * See the datasheet [1] for more details.
+ * [1]:https://github.com/sophgo/sophgo-doc/tree/main/SG2042/TRM
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/reset.h>
+
+/*
+ * Offset RegisterName
+ * 0x0000 HLPERIOD0
+ * 0x0004 PERIOD0
+ * 0x0008 HLPERIOD1
+ * 0x000C PERIOD1
+ * 0x0010 HLPERIOD2
+ * 0x0014 PERIOD2
+ * 0x0018 HLPERIOD3
+ * 0x001C PERIOD3
+ * Four groups and every group is composed of HLPERIOD & PERIOD
+ */
+#define SG2042_PWM_HLPERIOD(chan) ((chan) * 8 + 0)
+#define SG2042_PWM_PERIOD(chan) ((chan) * 8 + 4)
+
+#define SG2042_PWM_CHANNELNUM	4
+
+/**
+ * struct sg2042_pwm_ddata - private driver data
+ * @base:		base address of mapped PWM registers
+ * @clk_rate_hz:	rate of base clock in HZ
+ */
+struct sg2042_pwm_ddata {
+	void __iomem *base;
+	unsigned long clk_rate_hz;
+};
+
+/*
+ * period_ticks: PERIOD
+ * hlperiod_ticks: HLPERIOD
+ */
+static void pwm_sg2042_config(struct sg2042_pwm_ddata *ddata, unsigned int chan,
+			      u32 period_ticks, u32 hlperiod_ticks)
+{
+	void __iomem *base = ddata->base;
+
+	writel(period_ticks, base + SG2042_PWM_PERIOD(chan));
+	writel(hlperiod_ticks, base + SG2042_PWM_HLPERIOD(chan));
+}
+
+static int pwm_sg2042_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
+{
+	struct sg2042_pwm_ddata *ddata = pwmchip_get_drvdata(chip);
+	u32 hlperiod_ticks;
+	u32 period_ticks;
+
+	if (state->polarity == PWM_POLARITY_INVERSED)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		pwm_sg2042_config(ddata, pwm->hwpwm, 0, 0);
+		return 0;
+	}
+
+	/*
+	 * Duration of High level (duty_cycle) = HLPERIOD x Period_of_input_clk
+	 * Duration of One Cycle (period) = PERIOD x Period_of_input_clk
+	 */
+	period_ticks = min(mul_u64_u64_div_u64(ddata->clk_rate_hz, state->period, NSEC_PER_SEC), U32_MAX);
+	hlperiod_ticks = min(mul_u64_u64_div_u64(ddata->clk_rate_hz, state->duty_cycle, NSEC_PER_SEC), U32_MAX);
+
+	dev_dbg(pwmchip_parent(chip), "chan[%u]: PERIOD=%u, HLPERIOD=%u\n",
+		pwm->hwpwm, period_ticks, hlperiod_ticks);
+
+	pwm_sg2042_config(ddata, pwm->hwpwm, period_ticks, hlperiod_ticks);
+
+	return 0;
+}
+
+static int pwm_sg2042_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_state *state)
+{
+	struct sg2042_pwm_ddata *ddata = pwmchip_get_drvdata(chip);
+	unsigned int chan = pwm->hwpwm;
+	u32 hlperiod_ticks;
+	u32 period_ticks;
+
+	period_ticks = readl(ddata->base + SG2042_PWM_PERIOD(chan));
+	hlperiod_ticks = readl(ddata->base + SG2042_PWM_HLPERIOD(chan));
+
+	if (!period_ticks) {
+		state->enabled = false;
+		return 0;
+	}
+
+	if (hlperiod_ticks > period_ticks)
+		hlperiod_ticks = period_ticks;
+
+	state->enabled = true;
+	state->period = DIV_ROUND_UP_ULL((u64)period_ticks * NSEC_PER_SEC, ddata->clk_rate_hz);
+	state->duty_cycle = DIV_ROUND_UP_ULL((u64)hlperiod_ticks * NSEC_PER_SEC, ddata->clk_rate_hz);
+	state->polarity = PWM_POLARITY_NORMAL;
+
+	return 0;
+}
+
+static const struct pwm_ops pwm_sg2042_ops = {
+	.apply = pwm_sg2042_apply,
+	.get_state = pwm_sg2042_get_state,
+};
+
+static const struct of_device_id sg2042_pwm_ids[] = {
+	{ .compatible = "sophgo,sg2042-pwm" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sg2042_pwm_ids);
+
+static int pwm_sg2042_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sg2042_pwm_ddata *ddata;
+	struct reset_control *rst;
+	struct pwm_chip *chip;
+	struct clk *clk;
+	int ret;
+
+	chip = devm_pwmchip_alloc(dev, SG2042_PWM_CHANNELNUM, sizeof(*ddata));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	ddata = pwmchip_get_drvdata(chip);
+
+	ddata->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ddata->base))
+		return PTR_ERR(ddata->base);
+
+	clk = devm_clk_get_enabled(dev, "apb");
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk), "Failed to get base clk\n");
+
+	ret = devm_clk_rate_exclusive_get(dev, clk);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get exclusive rate\n");
+
+	ddata->clk_rate_hz = clk_get_rate(clk);
+	/* period = PERIOD * NSEC_PER_SEC / clk_rate_hz */
+	if (!ddata->clk_rate_hz || ddata->clk_rate_hz > NSEC_PER_SEC)
+		return dev_err_probe(dev, -EINVAL,
+				     "Invalid clock rate: %lu\n", ddata->clk_rate_hz);
+
+	rst = devm_reset_control_get_optional_shared_deasserted(dev, NULL);
+	if (IS_ERR(rst))
+		return dev_err_probe(dev, PTR_ERR(rst), "Failed to get reset\n");
+
+	chip->ops = &pwm_sg2042_ops;
+	chip->atomic = true;
+
+	ret = devm_pwmchip_add(dev, chip);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to register PWM chip\n");
+
+	return 0;
+}
+
+static struct platform_driver pwm_sg2042_driver = {
+	.driver	= {
+		.name = "sg2042-pwm",
+		.of_match_table = sg2042_pwm_ids,
+	},
+	.probe = pwm_sg2042_probe,
+};
+module_platform_driver(pwm_sg2042_driver);
+
+MODULE_AUTHOR("Chen Wang");
+MODULE_DESCRIPTION("Sophgo SG2042 PWM driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index a59de4de18b6..ec2c05c9ee7a 100644
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -103,22 +103,16 @@ static int stm32_pwm_round_waveform_tohw(struct pwm_chip *chip,
 		if (ret)
 			goto out;
 
-		/*
-		 * calculate the best value for ARR for the given PSC, refuse if
-		 * the resulting period gets bigger than the requested one.
-		 */
 		arr = mul_u64_u64_div_u64(wf->period_length_ns, rate,
 					  (u64)NSEC_PER_SEC * (wfhw->psc + 1));
 		if (arr <= wfhw->arr) {
 			/*
-			 * requested period is small than the currently
+			 * requested period is smaller than the currently
 			 * configured and unchangable period, report back the smallest
-			 * possible period, i.e. the current state; Initialize
-			 * ccr to anything valid.
+			 * possible period, i.e. the current state and return 1
+			 * to indicate the wrong rounding direction.
 			 */
-			wfhw->ccr = 0;
 			ret = 1;
-			goto out;
 		}
 
 	} else {
diff --git a/drivers/pwm/pwm-stmpe.c b/drivers/pwm/pwm-stmpe.c
index bb91062d5f1d..73f12843999a 100644
--- a/drivers/pwm/pwm-stmpe.c
+++ b/drivers/pwm/pwm-stmpe.c
@@ -326,12 +326,33 @@ static int __init stmpe_pwm_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	platform_set_drvdata(pdev, chip);
+
 	return 0;
 }
 
-static struct platform_driver stmpe_pwm_driver = {
+static void __exit stmpe_pwm_remove(struct platform_device *pdev)
+{
+	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
+	struct pwm_chip *chip = platform_get_drvdata(pdev);
+
+	pwmchip_remove(chip);
+	stmpe_disable(stmpe, STMPE_BLOCK_PWM);
+}
+
+/*
+ * stmpe_pwm_remove() lives in .exit.text. For drivers registered via
+ * module_platform_driver_probe() this is ok because they cannot get unbound at
+ * runtime. So mark the driver struct with __refdata to prevent modpost
+ * triggering a section mismatch warning.
+ */
+static struct platform_driver stmpe_pwm_driver __refdata = {
 	.driver = {
 		.name = "stmpe-pwm",
 	},
+	.remove = __exit_p(stmpe_pwm_remove),
 };
-builtin_platform_driver_probe(stmpe_pwm_driver, stmpe_pwm_probe);
+module_platform_driver_probe(stmpe_pwm_driver, stmpe_pwm_probe);
+
+MODULE_DESCRIPTION("STMPE expander PWM");
+MODULE_LICENSE("GPL");