drivers/pwm/pwm_mchp_xec.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * Copyright (c) 2019 Intel Corporation
  * Copyright (c) 2022 Microchip Technololgy Inc.
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 #define DT_DRV_COMPAT microchip_xec_pwm

 #include <errno.h>
 #include <stdlib.h>
 #include <stdint.h>

 #include <zephyr/device.h>
 #include <zephyr/drivers/pwm.h>
 #ifdef CONFIG_SOC_SERIES_MEC172X
 #include <zephyr/drivers/clock_control/mchp_xec_clock_control.h>
 #include <zephyr/drivers/interrupt_controller/intc_mchp_xec_ecia.h>
 #endif
 #ifdef CONFIG_PINCTRL
 #include <zephyr/drivers/pinctrl.h>
 #endif
 #include <zephyr/logging/log.h>

 #include <soc.h>

 LOG_MODULE_REGISTER(pwm_mchp_xec, CONFIG_PWM_LOG_LEVEL);

 /* Minimal on/off are 1 & 1 both are incremented, so 4.
  * 0 cannot be set (used for full low/high output) so a
  * combination of on_off of 2 is not possible.
  */
 #define XEC_PWM_LOWEST_ON_OFF	4U
 /* Maximal on/off are UINT16_T, both are incremented.
  * Multiplied by the highest divider: 16
  */
 #define XEC_PWM_HIGHEST_ON_OFF	(2U * (UINT16_MAX + 1U) * 16U)

 #define XEC_PWM_MIN_HIGH_CLK_FREQ			\
 	(MCHP_PWM_INPUT_FREQ_HI / XEC_PWM_HIGHEST_ON_OFF)
 #define XEC_PWM_MAX_LOW_CLK_FREQ			\
 	(MCHP_PWM_INPUT_FREQ_LO / XEC_PWM_LOWEST_ON_OFF)
 /* Precision factor for frequency calculation
  * To mitigate frequency comparision up to the first digit after 0.
  */
 #define XEC_PWM_FREQ_PF		10U
 /* Precision factor for DC calculation
  * To avoid losing some digits after 0.
  */
 #define XEC_PWM_DC_PF		100000U
 /* Lowest reachable frequency */
 #define XEC_PWM_FREQ_LIMIT	1 /* 0.1hz * XEC_PWM_FREQ_PF */

 struct pwm_xec_config {
 	struct pwm_regs * const regs;
 	uint8_t pcr_idx;
 	uint8_t pcr_pos;
 #ifdef CONFIG_PINCTRL
 	const struct pinctrl_dev_config *pcfg;
 #endif
 };

 struct xec_params {
 	uint32_t on;
 	uint32_t off;
 	uint8_t div;
 };

 #define NUM_DIV_ELEMS		16

 static const uint32_t max_freq_high_on_div[NUM_DIV_ELEMS] = {
 	48000000,
 	24000000,
 	16000000,
 	12000000,
 	9600000,
 	8000000,
 	6857142,
 	6000000,
 	5333333,
 	4800000,
 	4363636,
 	4000000,
 	3692307,
 	3428571,
 	3200000,
 	3000000,
 };

 static const uint32_t max_freq_low_on_div[NUM_DIV_ELEMS] = {
 	100000,
 	50000,
 	33333,
 	25000,
 	20000,
 	16666,
 	14285,
 	12500,
 	11111,
 	10000,
 	9090,
 	8333,
 	7692,
 	7142,
 	6666,
 	6250,
 };

 static uint32_t xec_compute_frequency(uint32_t clk, uint32_t on, uint32_t off)
 {
 	return ((clk * XEC_PWM_FREQ_PF)/((on + 1) + (off + 1)));
 }

 static uint16_t xec_select_div(uint32_t freq, const uint32_t max_freq[16])
 {
 	uint8_t i;

 	if (freq >= max_freq[3]) {
 		return 0;
 	}

 	freq *= XEC_PWM_LOWEST_ON_OFF;

 	for (i = 0; i < 15; i++) {
 		if (freq >= max_freq[i]) {
 			break;
 		}
 	}

 	return i;
 }

 static void xec_compute_on_off(uint32_t freq, uint32_t dc, uint32_t clk,
 			       uint32_t *on, uint32_t *off)
 {
 	uint64_t on_off;

 	on_off = (clk * 10) / freq;

 	*on = ((on_off * dc) / XEC_PWM_DC_PF) - 1;
 	*off = on_off - *on - 2;
 }

 static uint32_t xec_compute_dc(uint32_t on, uint32_t off)
 {
 	int dc = (on + 1) + (off + 1);

 	/* Make calculation in uint64_t since XEC_PWM_DC_PF is large */
 	dc = (((uint64_t)(on + 1) * XEC_PWM_DC_PF) / dc);

 	return (uint32_t)dc;
 }

 static uint16_t xec_compare_div_on_off(uint32_t target_freq, uint32_t dc,
 				       const uint32_t max_freq[16],
 				       uint8_t div_a, uint8_t div_b,
 				       uint32_t *on_a, uint32_t *off_a)
 {
 	uint32_t freq_a, freq_b, on_b, off_b;

 	xec_compute_on_off(target_freq, dc, max_freq[div_a],
 			   on_a, off_a);

 	freq_a = xec_compute_frequency(max_freq[div_a], *on_a, *off_a);

 	xec_compute_on_off(target_freq, dc, max_freq[div_b],
 			   &on_b, &off_b);

 	freq_b = xec_compute_frequency(max_freq[div_b], on_b, off_b);

 	if ((target_freq - freq_a) < (target_freq - freq_b)) {
 		if ((*on_a <= UINT16_MAX) && (*off_a <= UINT16_MAX)) {
 			return div_a;
 		}
 	}

 	if ((on_b <= UINT16_MAX) && (off_b <= UINT16_MAX)) {
 		*on_a = on_b;
 		*off_a = off_b;

 		return div_b;
 	}

 	return div_a;
 }

 static uint8_t xec_select_best_div_on_off(uint32_t target_freq, uint32_t dc,
 					  const uint32_t max_freq[16],
 					  uint32_t *on, uint32_t *off)
 {
 	int div_comp;
 	uint8_t div;

 	div = xec_select_div(target_freq, max_freq);

 	for (div_comp = (int)div - 1; div_comp >= 0; div_comp--) {
 		div = xec_compare_div_on_off(target_freq, dc, max_freq,
 					     div, div_comp, on, off);
 	}

 	return div;
 }

 static struct xec_params *xec_compare_params(uint32_t target_freq,
 					     struct xec_params *hc_params,
 					     struct xec_params *lc_params)
 {
 	struct xec_params *params;
 	uint32_t freq_h = 0;
 	uint32_t freq_l = 0;

 	if (hc_params->div < NUM_DIV_ELEMS) {
 		freq_h = xec_compute_frequency(
 				max_freq_high_on_div[hc_params->div],
 				hc_params->on,
 				hc_params->off);
 	}

 	if (lc_params->div < NUM_DIV_ELEMS) {
 		freq_l = xec_compute_frequency(
 				max_freq_low_on_div[lc_params->div],
 				lc_params->on,
 				lc_params->off);
 	}

 	if (abs((int)target_freq - (int)freq_h) <
 	    abs((int)target_freq - (int)freq_l)) {
 		params = hc_params;
 	} else {
 		params = lc_params;
 	}

 	LOG_DBG("\tFrequency (x%u): %u", XEC_PWM_FREQ_PF, freq_h);
 	LOG_DBG("\tOn %s clock, ON %u OFF %u DIV %u",
 		params == hc_params ? "High" : "Low",
 		params->on, params->off, params->div);

 	return params;
 }

 static void xec_compute_and_set_parameters(const struct device *dev,
 					   uint32_t target_freq,
 					   uint32_t on, uint32_t off)
 {
 	const struct pwm_xec_config * const cfg = dev->config;
 	struct pwm_regs * const regs = cfg->regs;
 	bool compute_high, compute_low;
 	struct xec_params hc_params;
 	struct xec_params lc_params;
 	struct xec_params *params;
 	uint32_t dc, cfgval;

 	dc = xec_compute_dc(on, off);

 	compute_high = (target_freq >= XEC_PWM_MIN_HIGH_CLK_FREQ);
 	compute_low = (target_freq <= XEC_PWM_MAX_LOW_CLK_FREQ);

 	LOG_DBG("Target freq (x%u): %u and DC %u per-cent",
 		XEC_PWM_FREQ_PF, target_freq, (dc / 1000));

 	if (compute_high) {
 		if (!compute_low
 		    && (on <= UINT16_MAX)
 		    && (off <= UINT16_MAX)) {
 			hc_params.on = on;
 			hc_params.off = off;
 			hc_params.div = 0;
 			lc_params.div = UINT8_MAX;

 			goto done;
 		}

 		hc_params.div = xec_select_best_div_on_off(
 					target_freq, dc,
 					max_freq_high_on_div,
 					&hc_params.on,
 					&hc_params.off);
 		LOG_DBG("Best div high: %u (on/off: %u/%u)",
 			hc_params.div, hc_params.on, hc_params.off);
 	} else {
 		hc_params.div = UINT8_MAX;
 	}

 	if (compute_low) {
 		lc_params.div = xec_select_best_div_on_off(
 					target_freq, dc,
 					max_freq_low_on_div,
 					&lc_params.on,
 					&lc_params.off);
 		LOG_DBG("Best div low: %u (on/off: %u/%u)",
 			lc_params.div, lc_params.on, lc_params.off);
 	} else {
 		lc_params.div = UINT8_MAX;
 	}
 done:
 	regs->CONFIG &= ~MCHP_PWM_CFG_ENABLE;

 	cfgval = regs->CONFIG;

 	params = xec_compare_params(target_freq, &hc_params, &lc_params);
 	if (params == &hc_params) {
 		cfgval |= MCHP_PWM_CFG_CLK_SEL_48M;
 	} else {
 		cfgval |= MCHP_PWM_CFG_CLK_SEL_100K;
 	}

 	regs->COUNT_ON = params->on;
 	regs->COUNT_OFF = params->off;
 	cfgval |= MCHP_PWM_CFG_CLK_PRE_DIV(params->div);
 	cfgval |= MCHP_PWM_CFG_ENABLE;

 	regs->CONFIG = cfgval;
 }

 static int pwm_xec_set_cycles(const struct device *dev, uint32_t channel,
 			      uint32_t period_cycles, uint32_t pulse_cycles,
 			      pwm_flags_t flags)
 {
 	const struct pwm_xec_config * const cfg = dev->config;
 	struct pwm_regs * const regs = cfg->regs;
 	uint32_t target_freq;
 	uint32_t on, off;

 	if (channel > 0) {
 		return -EIO;
 	}

 	if (flags) {
 		/* PWM polarity not supported (yet?) */
 		return -ENOTSUP;
 	}

 	on = pulse_cycles;
 	off = period_cycles - pulse_cycles;

 	target_freq = xec_compute_frequency(MCHP_PWM_INPUT_FREQ_HI, on, off);
 	if (target_freq < XEC_PWM_FREQ_LIMIT) {
 		LOG_DBG("Target frequency below limit");
 		return -EINVAL;
 	}

 	if ((pulse_cycles == 0U) && (period_cycles == 0U)) {
 		regs->CONFIG &= ~MCHP_PWM_CFG_ENABLE;
 	} else if ((pulse_cycles == 0U) && (period_cycles > 0U)) {
 		regs->COUNT_ON = 0;
 		regs->COUNT_OFF = 1;
 	} else if ((pulse_cycles > 0U) && (period_cycles == 0U)) {
 		regs->COUNT_ON = 1;
 		regs->COUNT_OFF = 0;
 	} else {
 		xec_compute_and_set_parameters(dev, target_freq, on, off);
 	}

 	return 0;
 }

 static int pwm_xec_get_cycles_per_sec(const struct device *dev,
 				      uint32_t channel, uint64_t *cycles)
 {
 	ARG_UNUSED(dev);

 	if (channel > 0) {
 		return -EIO;
 	}

 	if (cycles) {
 		/* User does not have to know about lowest clock,
 		 * the driver will select the most relevant one.
 		 */
 		*cycles = MCHP_PWM_INPUT_FREQ_HI;
 	}

 	return 0;
 }

 static const struct pwm_driver_api pwm_xec_driver_api = {
 	.set_cycles = pwm_xec_set_cycles,
 	.get_cycles_per_sec = pwm_xec_get_cycles_per_sec,
 };

 static int pwm_xec_init(const struct device *dev)
 {
 #ifdef CONFIG_PINCTRL
 	const struct pwm_xec_config * const cfg = dev->config;
 	int ret = pinctrl_apply_state(cfg->pcfg, PINCTRL_STATE_DEFAULT);

 	if (ret != 0) {
 		LOG_ERR("XEC PWM pinctrl init failed (%d)", ret);
 		return ret;
 	}
 #else
 	ARG_UNUSED(dev);
 #endif

 	return 0;
 }

 #ifdef CONFIG_PINCTRL
 #define XEC_PWM_PINCTRL_DEF(inst) PINCTRL_DT_INST_DEFINE(inst)
 #define XEC_PWM_CONFIG(inst)							\
 	static struct pwm_xec_config pwm_xec_config_##inst = {			\
 		.regs = (struct pwm_regs * const)DT_INST_REG_ADDR(inst),	\
 		.pcr_idx = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 0),		\
 		.pcr_pos = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 1),		\
 		.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst),			\
 	};

 #else
 #define XEC_PWM_PINCTRL_DEF(inst)
 #define XEC_PWM_CONFIG(inst)							\
 	static struct pwm_xec_config pwm_xec_config_##inst = {			\
 		.regs = (struct pwm_regs * const)DT_INST_REG_ADDR(inst),	\
 		.pcr_idx = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 0),		\
 		.pcr_pos = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 1),		\
 	};
 #endif

 #define XEC_PWM_DEVICE_INIT(index)					\
 									\
 	XEC_PWM_PINCTRL_DEF(index);					\
 									\
 	XEC_PWM_CONFIG(index);						\
 									\
 	DEVICE_DT_INST_DEFINE(index, &pwm_xec_init,			\
 			      NULL,					\
 			      NULL,					\
 			      &pwm_xec_config_##index, POST_KERNEL,	\
 			      CONFIG_KERNEL_INIT_PRIORITY_DEVICE,	\
 			      &pwm_xec_driver_api);

 DT_INST_FOREACH_STATUS_OKAY(XEC_PWM_DEVICE_INIT)
	/*
	* Copyright (c) 2019 Intel Corporation
	* Copyright (c) 2022 Microchip Technololgy Inc.
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	#define DT_DRV_COMPAT microchip_xec_pwm

	#include <errno.h>
	#include <stdlib.h>
	#include <stdint.h>

	#include <zephyr/device.h>
	#include <zephyr/drivers/pwm.h>
	#ifdef CONFIG_SOC_SERIES_MEC172X
	#include <zephyr/drivers/clock_control/mchp_xec_clock_control.h>
	#include <zephyr/drivers/interrupt_controller/intc_mchp_xec_ecia.h>
	#endif
	#ifdef CONFIG_PINCTRL
	#include <zephyr/drivers/pinctrl.h>
	#endif
	#include <zephyr/logging/log.h>

	#include <soc.h>

	LOG_MODULE_REGISTER(pwm_mchp_xec, CONFIG_PWM_LOG_LEVEL);

	/* Minimal on/off are 1 & 1 both are incremented, so 4.
	* 0 cannot be set (used for full low/high output) so a
	* combination of on_off of 2 is not possible.
	*/
	#define XEC_PWM_LOWEST_ON_OFF 4U
	/* Maximal on/off are UINT16_T, both are incremented.
	* Multiplied by the highest divider: 16
	*/
	#define XEC_PWM_HIGHEST_ON_OFF (2U * (UINT16_MAX + 1U) * 16U)

	#define XEC_PWM_MIN_HIGH_CLK_FREQ \
	(MCHP_PWM_INPUT_FREQ_HI / XEC_PWM_HIGHEST_ON_OFF)
	#define XEC_PWM_MAX_LOW_CLK_FREQ \
	(MCHP_PWM_INPUT_FREQ_LO / XEC_PWM_LOWEST_ON_OFF)
	/* Precision factor for frequency calculation
	* To mitigate frequency comparision up to the first digit after 0.
	*/
	#define XEC_PWM_FREQ_PF 10U
	/* Precision factor for DC calculation
	* To avoid losing some digits after 0.
	*/
	#define XEC_PWM_DC_PF 100000U
	/* Lowest reachable frequency */
	#define XEC_PWM_FREQ_LIMIT 1 /* 0.1hz * XEC_PWM_FREQ_PF */

	struct pwm_xec_config {
	struct pwm_regs * const regs;
	uint8_t pcr_idx;
	uint8_t pcr_pos;
	#ifdef CONFIG_PINCTRL
	const struct pinctrl_dev_config *pcfg;
	#endif
	};

	struct xec_params {
	uint32_t on;
	uint32_t off;
	uint8_t div;
	};

	#define NUM_DIV_ELEMS 16

	static const uint32_t max_freq_high_on_div[NUM_DIV_ELEMS] = {
	48000000,
	24000000,
	16000000,
	12000000,
	9600000,
	8000000,
	6857142,
	6000000,
	5333333,
	4800000,
	4363636,
	4000000,
	3692307,
	3428571,
	3200000,
	3000000,
	};

	static const uint32_t max_freq_low_on_div[NUM_DIV_ELEMS] = {
	100000,
	50000,
	33333,
	25000,
	20000,
	16666,
	14285,
	12500,
	11111,
	10000,
	9090,
	8333,
	7692,
	7142,
	6666,
	6250,
	};

	static uint32_t xec_compute_frequency(uint32_t clk, uint32_t on, uint32_t off)
	{
	return ((clk * XEC_PWM_FREQ_PF)/((on + 1) + (off + 1)));
	}

	static uint16_t xec_select_div(uint32_t freq, const uint32_t max_freq[16])
	{
	uint8_t i;

	if (freq >= max_freq[3]) {
	return 0;
	}

	freq *= XEC_PWM_LOWEST_ON_OFF;

	for (i = 0; i < 15; i++) {
	if (freq >= max_freq[i]) {
	break;
	}
	}

	return i;
	}

	static void xec_compute_on_off(uint32_t freq, uint32_t dc, uint32_t clk,
	uint32_t on, uint32_t off)
	{
	uint64_t on_off;

	on_off = (clk * 10) / freq;

	on = ((on_off dc) / XEC_PWM_DC_PF) - 1;
	off = on_off - on - 2;
	}

	static uint32_t xec_compute_dc(uint32_t on, uint32_t off)
	{
	int dc = (on + 1) + (off + 1);

	/* Make calculation in uint64_t since XEC_PWM_DC_PF is large */
	dc = (((uint64_t)(on + 1) * XEC_PWM_DC_PF) / dc);

	return (uint32_t)dc;
	}

	static uint16_t xec_compare_div_on_off(uint32_t target_freq, uint32_t dc,
	const uint32_t max_freq[16],
	uint8_t div_a, uint8_t div_b,
	uint32_t on_a, uint32_t off_a)
	{
	uint32_t freq_a, freq_b, on_b, off_b;

	xec_compute_on_off(target_freq, dc, max_freq[div_a],
	on_a, off_a);

	freq_a = xec_compute_frequency(max_freq[div_a], on_a, off_a);

	xec_compute_on_off(target_freq, dc, max_freq[div_b],
	&on_b, &off_b);

	freq_b = xec_compute_frequency(max_freq[div_b], on_b, off_b);

	if ((target_freq - freq_a) < (target_freq - freq_b)) {
	if ((on_a <= UINT16_MAX) && (off_a <= UINT16_MAX)) {
	return div_a;
	}
	}

	if ((on_b <= UINT16_MAX) && (off_b <= UINT16_MAX)) {
	*on_a = on_b;
	*off_a = off_b;

	return div_b;
	}

	return div_a;
	}

	static uint8_t xec_select_best_div_on_off(uint32_t target_freq, uint32_t dc,
	const uint32_t max_freq[16],
	uint32_t on, uint32_t off)
	{
	int div_comp;
	uint8_t div;

	div = xec_select_div(target_freq, max_freq);

	for (div_comp = (int)div - 1; div_comp >= 0; div_comp--) {
	div = xec_compare_div_on_off(target_freq, dc, max_freq,
	div, div_comp, on, off);
	}

	return div;
	}

	static struct xec_params *xec_compare_params(uint32_t target_freq,
	struct xec_params *hc_params,
	struct xec_params *lc_params)
	{
	struct xec_params *params;
	uint32_t freq_h = 0;
	uint32_t freq_l = 0;

	if (hc_params->div < NUM_DIV_ELEMS) {
	freq_h = xec_compute_frequency(
	max_freq_high_on_div[hc_params->div],
	hc_params->on,
	hc_params->off);
	}

	if (lc_params->div < NUM_DIV_ELEMS) {
	freq_l = xec_compute_frequency(
	max_freq_low_on_div[lc_params->div],
	lc_params->on,
	lc_params->off);
	}

	if (abs((int)target_freq - (int)freq_h) <
	abs((int)target_freq - (int)freq_l)) {
	params = hc_params;
	} else {
	params = lc_params;
	}

	LOG_DBG("\tFrequency (x%u): %u", XEC_PWM_FREQ_PF, freq_h);
	LOG_DBG("\tOn %s clock, ON %u OFF %u DIV %u",
	params == hc_params ? "High" : "Low",
	params->on, params->off, params->div);

	return params;
	}

	static void xec_compute_and_set_parameters(const struct device *dev,
	uint32_t target_freq,
	uint32_t on, uint32_t off)
	{
	const struct pwm_xec_config * const cfg = dev->config;
	struct pwm_regs * const regs = cfg->regs;
	bool compute_high, compute_low;
	struct xec_params hc_params;
	struct xec_params lc_params;
	struct xec_params *params;
	uint32_t dc, cfgval;

	dc = xec_compute_dc(on, off);

	compute_high = (target_freq >= XEC_PWM_MIN_HIGH_CLK_FREQ);
	compute_low = (target_freq <= XEC_PWM_MAX_LOW_CLK_FREQ);

	LOG_DBG("Target freq (x%u): %u and DC %u per-cent",
	XEC_PWM_FREQ_PF, target_freq, (dc / 1000));

	if (compute_high) {
	if (!compute_low
	&& (on <= UINT16_MAX)
	&& (off <= UINT16_MAX)) {
	hc_params.on = on;
	hc_params.off = off;
	hc_params.div = 0;
	lc_params.div = UINT8_MAX;

	goto done;
	}

	hc_params.div = xec_select_best_div_on_off(
	target_freq, dc,
	max_freq_high_on_div,
	&hc_params.on,
	&hc_params.off);
	LOG_DBG("Best div high: %u (on/off: %u/%u)",
	hc_params.div, hc_params.on, hc_params.off);
	} else {
	hc_params.div = UINT8_MAX;
	}

	if (compute_low) {
	lc_params.div = xec_select_best_div_on_off(
	target_freq, dc,
	max_freq_low_on_div,
	&lc_params.on,
	&lc_params.off);
	LOG_DBG("Best div low: %u (on/off: %u/%u)",
	lc_params.div, lc_params.on, lc_params.off);
	} else {
	lc_params.div = UINT8_MAX;
	}
	done:
	regs->CONFIG &= ~MCHP_PWM_CFG_ENABLE;

	cfgval = regs->CONFIG;

	params = xec_compare_params(target_freq, &hc_params, &lc_params);
	if (params == &hc_params) {
	cfgval \|= MCHP_PWM_CFG_CLK_SEL_48M;
	} else {
	cfgval \|= MCHP_PWM_CFG_CLK_SEL_100K;
	}

	regs->COUNT_ON = params->on;
	regs->COUNT_OFF = params->off;
	cfgval \|= MCHP_PWM_CFG_CLK_PRE_DIV(params->div);
	cfgval \|= MCHP_PWM_CFG_ENABLE;

	regs->CONFIG = cfgval;
	}

	static int pwm_xec_set_cycles(const struct device *dev, uint32_t channel,
	uint32_t period_cycles, uint32_t pulse_cycles,
	pwm_flags_t flags)
	{
	const struct pwm_xec_config * const cfg = dev->config;
	struct pwm_regs * const regs = cfg->regs;
	uint32_t target_freq;
	uint32_t on, off;

	if (channel > 0) {
	return -EIO;
	}

	if (flags) {
	/* PWM polarity not supported (yet?) */
	return -ENOTSUP;
	}

	on = pulse_cycles;
	off = period_cycles - pulse_cycles;

	target_freq = xec_compute_frequency(MCHP_PWM_INPUT_FREQ_HI, on, off);
	if (target_freq < XEC_PWM_FREQ_LIMIT) {
	LOG_DBG("Target frequency below limit");
	return -EINVAL;
	}

	if ((pulse_cycles == 0U) && (period_cycles == 0U)) {
	regs->CONFIG &= ~MCHP_PWM_CFG_ENABLE;
	} else if ((pulse_cycles == 0U) && (period_cycles > 0U)) {
	regs->COUNT_ON = 0;
	regs->COUNT_OFF = 1;
	} else if ((pulse_cycles > 0U) && (period_cycles == 0U)) {
	regs->COUNT_ON = 1;
	regs->COUNT_OFF = 0;
	} else {
	xec_compute_and_set_parameters(dev, target_freq, on, off);
	}

	return 0;
	}

	static int pwm_xec_get_cycles_per_sec(const struct device *dev,
	uint32_t channel, uint64_t *cycles)
	{
	ARG_UNUSED(dev);

	if (channel > 0) {
	return -EIO;
	}

	if (cycles) {
	/* User does not have to know about lowest clock,
	* the driver will select the most relevant one.
	*/
	*cycles = MCHP_PWM_INPUT_FREQ_HI;
	}

	return 0;
	}

	static const struct pwm_driver_api pwm_xec_driver_api = {
	.set_cycles = pwm_xec_set_cycles,
	.get_cycles_per_sec = pwm_xec_get_cycles_per_sec,
	};

	static int pwm_xec_init(const struct device *dev)
	{
	#ifdef CONFIG_PINCTRL
	const struct pwm_xec_config * const cfg = dev->config;
	int ret = pinctrl_apply_state(cfg->pcfg, PINCTRL_STATE_DEFAULT);

	if (ret != 0) {
	LOG_ERR("XEC PWM pinctrl init failed (%d)", ret);
	return ret;
	}
	#else
	ARG_UNUSED(dev);
	#endif

	return 0;
	}

	#ifdef CONFIG_PINCTRL
	#define XEC_PWM_PINCTRL_DEF(inst) PINCTRL_DT_INST_DEFINE(inst)
	#define XEC_PWM_CONFIG(inst) \
	static struct pwm_xec_config pwm_xec_config_##inst = { \
	.regs = (struct pwm_regs * const)DT_INST_REG_ADDR(inst), \
	.pcr_idx = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 0), \
	.pcr_pos = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 1), \
	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst), \
	};

	#else
	#define XEC_PWM_PINCTRL_DEF(inst)
	#define XEC_PWM_CONFIG(inst) \
	static struct pwm_xec_config pwm_xec_config_##inst = { \
	.regs = (struct pwm_regs * const)DT_INST_REG_ADDR(inst), \
	.pcr_idx = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 0), \
	.pcr_pos = (uint8_t)DT_INST_PROP_BY_IDX(inst, pcrs, 1), \
	};
	#endif

	#define XEC_PWM_DEVICE_INIT(index) \
	\
	XEC_PWM_PINCTRL_DEF(index); \
	\
	XEC_PWM_CONFIG(index); \
	\
	DEVICE_DT_INST_DEFINE(index, &pwm_xec_init, \
	NULL, \
	NULL, \
	&pwm_xec_config_##index, POST_KERNEL, \
	CONFIG_KERNEL_INIT_PRIORITY_DEVICE, \
	&pwm_xec_driver_api);

	DT_INST_FOREACH_STATUS_OKAY(XEC_PWM_DEVICE_INIT)