drivers/pwm/pwm-aspeed.c - u-boot - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2022 Aspeed Technology Inc.
  *
  * PWM controller driver for Aspeed ast2600 SoCs.
  * This drivers doesn't support earlier version of the IP.
  *
  * The formula of pwm period duration:
  * period duration = ((DIV_L + 1) * (PERIOD + 1) << DIV_H) / input-clk
  *
  * The formula of pwm duty cycle duration:
  * duty cycle duration = period duration * DUTY_CYCLE_FALLING_POINT / (PERIOD + 1)
  * = ((DIV_L + 1) * DUTY_CYCLE_FALLING_POINT << DIV_H) / input-clk
  *
  * The software driver fixes the period to 255, which causes the high-frequency
  * precision of the PWM to be coarse, in exchange for the fineness of the duty cycle.
  *
  * Register usage:
  * PIN_ENABLE: When it is unset the pwm controller will always output low to the extern.
  * Use to determine whether the PWM channel is enabled or disabled
  * CLK_ENABLE: When it is unset the pwm controller will reset the duty counter to 0 and
  * output low to the PIN_ENABLE mux after that the driver can still change the pwm period
  * and duty and the value will apply when CLK_ENABLE be set again.
  * Use to determine whether duty_cycle bigger than 0.
  * PWM_ASPEED_CTRL_INVERSE: When it is toggled the output value will inverse immediately.
  * PWM_ASPEED_DUTY_CYCLE_FALLING_POINT/PWM_ASPEED_DUTY_CYCLE_RISING_POINT: When these two
  * values are equal it means the duty cycle = 100%.
  *
  * Limitations:
  * - When changing both duty cycle and period, we cannot prevent in
  *   software that the output might produce a period with mixed
  *   settings.
  * - Disabling the PWM doesn't complete the current period.
  *
  * Improvements:
  * - When only changing one of duty cycle or period, our pwm controller will not
  *   generate the glitch, the configure will change at next cycle of pwm.
  *   This improvement can disable/enable through PWM_ASPEED_CTRL_DUTY_SYNC_DISABLE.
  */

 #include <common.h>
 #include <div64.h>
 #include <dm.h>
 #include <pwm.h>
 #include <clk.h>
 #include <reset.h>
 #include <regmap.h>
 #include <syscon.h>
 #include <dm/device_compat.h>
 #include <linux/math64.h>
 #include <linux/bitfield.h>
 #include <linux/time.h>
 #include <asm/io.h>

 /* The channel number of Aspeed pwm controller */
 #define PWM_ASPEED_NR_PWMS 16

 /* PWM Control Register */
 #define PWM_ASPEED_CTRL(ch) ((ch) * 0x10 + 0x00)
 #define PWM_ASPEED_CTRL_LOAD_SEL_RISING_AS_WDT BIT(19)
 #define PWM_ASPEED_CTRL_DUTY_LOAD_AS_WDT_ENABLE BIT(18)
 #define PWM_ASPEED_CTRL_DUTY_SYNC_DISABLE BIT(17)
 #define PWM_ASPEED_CTRL_CLK_ENABLE BIT(16)
 #define PWM_ASPEED_CTRL_LEVEL_OUTPUT BIT(15)
 #define PWM_ASPEED_CTRL_INVERSE BIT(14)
 #define PWM_ASPEED_CTRL_OPEN_DRAIN_ENABLE BIT(13)
 #define PWM_ASPEED_CTRL_PIN_ENABLE BIT(12)
 #define PWM_ASPEED_CTRL_CLK_DIV_H GENMASK(11, 8)
 #define PWM_ASPEED_CTRL_CLK_DIV_L GENMASK(7, 0)

 /* PWM Duty Cycle Register */
 #define PWM_ASPEED_DUTY_CYCLE(ch) ((ch) * 0x10 + 0x04)
 #define PWM_ASPEED_DUTY_CYCLE_PERIOD GENMASK(31, 24)
 #define PWM_ASPEED_DUTY_CYCLE_POINT_AS_WDT GENMASK(23, 16)
 #define PWM_ASPEED_DUTY_CYCLE_FALLING_POINT GENMASK(15, 8)
 #define PWM_ASPEED_DUTY_CYCLE_RISING_POINT GENMASK(7, 0)

 /* PWM fixed value */
 #define PWM_ASPEED_FIXED_PERIOD 0xff

 struct aspeed_pwm_priv {
 	struct clk clk;
 	struct regmap *regmap;
 	struct reset_ctl reset;
 };

 static int aspeed_pwm_set_invert(struct udevice *dev, uint channel, bool polarity)
 {
 	struct aspeed_pwm_priv *priv = dev_get_priv(dev);

 	if (channel >= PWM_ASPEED_NR_PWMS)
 		return -EINVAL;

 	regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL(channel),
 			   PWM_ASPEED_CTRL_INVERSE,
 			   FIELD_PREP(PWM_ASPEED_CTRL_INVERSE,
 				      polarity));
 	return 0;
 }

 static int aspeed_pwm_set_enable(struct udevice *dev, uint channel, bool enable)
 {
 	struct aspeed_pwm_priv *priv = dev_get_priv(dev);

 	if (channel >= PWM_ASPEED_NR_PWMS)
 		return -EINVAL;

 	regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL(channel),
 			   PWM_ASPEED_CTRL_PIN_ENABLE,
 			   enable ? PWM_ASPEED_CTRL_PIN_ENABLE : 0);
 	return 0;
 }

 static int aspeed_pwm_set_config(struct udevice *dev, uint channel,
 				 uint period_ns, uint duty_ns)
 {
 	struct aspeed_pwm_priv *priv = dev_get_priv(dev);
 	u32 duty_pt;
 	unsigned long rate;
 	u64 div_h, div_l, divisor;
 	bool clk_en;

 	if (channel >= PWM_ASPEED_NR_PWMS)
 		return -EINVAL;
 	dev_dbg(dev, "expect period: %dns, duty_cycle: %dns\n", period_ns,
 		duty_ns);

 	rate = clk_get_rate(&priv->clk);
 	/*
 	 * Pick the smallest value for div_h so that div_l can be the biggest
 	 * which results in a finer resolution near the target period value.
 	 */
 	divisor = (u64)NSEC_PER_SEC * (PWM_ASPEED_FIXED_PERIOD + 1) *
 		  (PWM_ASPEED_CTRL_CLK_DIV_L + 1);
 	div_h = order_base_2(div64_u64((u64)rate * period_ns + divisor - 1, divisor));
 	if (div_h > 0xf)
 		div_h = 0xf;

 	divisor = ((u64)NSEC_PER_SEC * (PWM_ASPEED_FIXED_PERIOD + 1)) << div_h;
 	div_l = div64_u64((u64)rate * period_ns, divisor);

 	if (div_l == 0)
 		return -ERANGE;

 	div_l -= 1;

 	if (div_l > 255)
 		div_l = 255;

 	dev_dbg(dev, "clk source: %ld div_h %lld, div_l : %lld\n", rate, div_h,
 		div_l);
 	/* duty_pt = duty_cycle * (PERIOD + 1) / period */
 	duty_pt = div64_u64(duty_ns * (u64)rate,
 			    (u64)NSEC_PER_SEC * (div_l + 1) << div_h);
 	dev_dbg(dev, "duty_cycle = %d, duty_pt = %d\n", duty_ns,
 		duty_pt);

 	if (duty_pt == 0) {
 		clk_en = 0;
 	} else {
 		clk_en = 1;
 		if (duty_pt >= (PWM_ASPEED_FIXED_PERIOD + 1))
 			duty_pt = 0;
 		/*
 		 * Fixed DUTY_CYCLE_PERIOD to its max value to get a
 		 * fine-grained resolution for duty_cycle at the expense of a
 		 * coarser period resolution.
 		 */
 		regmap_update_bits(priv->regmap, PWM_ASPEED_DUTY_CYCLE(channel),
 				   PWM_ASPEED_DUTY_CYCLE_PERIOD |
 				       PWM_ASPEED_DUTY_CYCLE_RISING_POINT |
 				       PWM_ASPEED_DUTY_CYCLE_FALLING_POINT,
 				   FIELD_PREP(PWM_ASPEED_DUTY_CYCLE_PERIOD,
 					      PWM_ASPEED_FIXED_PERIOD) |
 				       FIELD_PREP(PWM_ASPEED_DUTY_CYCLE_FALLING_POINT,
 						  duty_pt));
 	}

 	regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL(channel),
 			   PWM_ASPEED_CTRL_CLK_DIV_H |
 			       PWM_ASPEED_CTRL_CLK_DIV_L |
 			       PWM_ASPEED_CTRL_CLK_ENABLE,
 			   FIELD_PREP(PWM_ASPEED_CTRL_CLK_DIV_H, div_h) |
 			       FIELD_PREP(PWM_ASPEED_CTRL_CLK_DIV_L, div_l) |
 			       FIELD_PREP(PWM_ASPEED_CTRL_CLK_ENABLE, clk_en));
 	return 0;
 }

 static int aspeed_pwm_probe(struct udevice *dev)
 {
 	int ret;
 	struct aspeed_pwm_priv *priv = dev_get_priv(dev);
 	struct udevice *parent_dev = dev_get_parent(dev);

 	priv->regmap = syscon_node_to_regmap(dev_ofnode(dev->parent));
 	if (IS_ERR(priv->regmap)) {
 		dev_err(dev, "Couldn't get regmap\n");
 		return PTR_ERR(priv->regmap);
 	}

 	ret = clk_get_by_index(parent_dev, 0, &priv->clk);
 	if (ret < 0) {
 		dev_err(dev, "get clock failed\n");
 		return ret;
 	}

 	ret = reset_get_by_index(parent_dev, 0, &priv->reset);
 	if (ret) {
 		dev_err(dev, "get reset failed\n");
 		return ret;
 	}
 	ret = reset_deassert(&priv->reset);
 	if (ret) {
 		dev_err(dev, "cannot deassert reset control: %pe\n",
 			ERR_PTR(ret));
 		return ret;
 	}

 	return 0;
 }

 static int aspeed_pwm_remove(struct udevice *dev)
 {
 	struct aspeed_pwm_priv *priv = dev_get_priv(dev);

 	reset_assert(&priv->reset);

 	return 0;
 }

 static const struct pwm_ops aspeed_pwm_ops = {
 	.set_invert	= aspeed_pwm_set_invert,
 	.set_config	= aspeed_pwm_set_config,
 	.set_enable	= aspeed_pwm_set_enable,
 };

 static const struct udevice_id aspeed_pwm_ids[] = {
 	{ .compatible = "aspeed,ast2600-pwm" },
 	{ }
 };

 U_BOOT_DRIVER(aspeed_pwm) = {
 	.name = "aspeed_pwm",
 	.id = UCLASS_PWM,
 	.of_match = aspeed_pwm_ids,
 	.ops = &aspeed_pwm_ops,
 	.probe = aspeed_pwm_probe,
 	.remove = aspeed_pwm_remove,
 	.priv_auto = sizeof(struct aspeed_pwm_priv),
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2022 Aspeed Technology Inc.
	*
	* PWM controller driver for Aspeed ast2600 SoCs.
	* This drivers doesn't support earlier version of the IP.
	*
	* The formula of pwm period duration:
	* period duration = ((DIV_L + 1) * (PERIOD + 1) << DIV_H) / input-clk
	*
	* The formula of pwm duty cycle duration:
	* duty cycle duration = period duration * DUTY_CYCLE_FALLING_POINT / (PERIOD + 1)
	* = ((DIV_L + 1) * DUTY_CYCLE_FALLING_POINT << DIV_H) / input-clk
	*
	* The software driver fixes the period to 255, which causes the high-frequency
	* precision of the PWM to be coarse, in exchange for the fineness of the duty cycle.
	*
	* Register usage:
	* PIN_ENABLE: When it is unset the pwm controller will always output low to the extern.
	* Use to determine whether the PWM channel is enabled or disabled
	* CLK_ENABLE: When it is unset the pwm controller will reset the duty counter to 0 and
	* output low to the PIN_ENABLE mux after that the driver can still change the pwm period
	* and duty and the value will apply when CLK_ENABLE be set again.
	* Use to determine whether duty_cycle bigger than 0.
	* PWM_ASPEED_CTRL_INVERSE: When it is toggled the output value will inverse immediately.
	* PWM_ASPEED_DUTY_CYCLE_FALLING_POINT/PWM_ASPEED_DUTY_CYCLE_RISING_POINT: When these two
	* values are equal it means the duty cycle = 100%.
	*
	* Limitations:
	* - When changing both duty cycle and period, we cannot prevent in
	* software that the output might produce a period with mixed
	* settings.
	* - Disabling the PWM doesn't complete the current period.
	*
	* Improvements:
	* - When only changing one of duty cycle or period, our pwm controller will not
	* generate the glitch, the configure will change at next cycle of pwm.
	* This improvement can disable/enable through PWM_ASPEED_CTRL_DUTY_SYNC_DISABLE.
	*/

	#include <common.h>
	#include <div64.h>
	#include <dm.h>
	#include <pwm.h>
	#include <clk.h>
	#include <reset.h>
	#include <regmap.h>
	#include <syscon.h>
	#include <dm/device_compat.h>
	#include <linux/math64.h>
	#include <linux/bitfield.h>
	#include <linux/time.h>
	#include <asm/io.h>

	/* The channel number of Aspeed pwm controller */
	#define PWM_ASPEED_NR_PWMS 16

	/* PWM Control Register */
	#define PWM_ASPEED_CTRL(ch) ((ch) * 0x10 + 0x00)
	#define PWM_ASPEED_CTRL_LOAD_SEL_RISING_AS_WDT BIT(19)
	#define PWM_ASPEED_CTRL_DUTY_LOAD_AS_WDT_ENABLE BIT(18)
	#define PWM_ASPEED_CTRL_DUTY_SYNC_DISABLE BIT(17)
	#define PWM_ASPEED_CTRL_CLK_ENABLE BIT(16)
	#define PWM_ASPEED_CTRL_LEVEL_OUTPUT BIT(15)
	#define PWM_ASPEED_CTRL_INVERSE BIT(14)
	#define PWM_ASPEED_CTRL_OPEN_DRAIN_ENABLE BIT(13)
	#define PWM_ASPEED_CTRL_PIN_ENABLE BIT(12)
	#define PWM_ASPEED_CTRL_CLK_DIV_H GENMASK(11, 8)
	#define PWM_ASPEED_CTRL_CLK_DIV_L GENMASK(7, 0)

	/* PWM Duty Cycle Register */
	#define PWM_ASPEED_DUTY_CYCLE(ch) ((ch) * 0x10 + 0x04)
	#define PWM_ASPEED_DUTY_CYCLE_PERIOD GENMASK(31, 24)
	#define PWM_ASPEED_DUTY_CYCLE_POINT_AS_WDT GENMASK(23, 16)
	#define PWM_ASPEED_DUTY_CYCLE_FALLING_POINT GENMASK(15, 8)
	#define PWM_ASPEED_DUTY_CYCLE_RISING_POINT GENMASK(7, 0)

	/* PWM fixed value */
	#define PWM_ASPEED_FIXED_PERIOD 0xff

	struct aspeed_pwm_priv {
	struct clk clk;
	struct regmap *regmap;
	struct reset_ctl reset;
	};

	static int aspeed_pwm_set_invert(struct udevice *dev, uint channel, bool polarity)
	{
	struct aspeed_pwm_priv *priv = dev_get_priv(dev);

	if (channel >= PWM_ASPEED_NR_PWMS)
	return -EINVAL;

	regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL(channel),
	PWM_ASPEED_CTRL_INVERSE,
	FIELD_PREP(PWM_ASPEED_CTRL_INVERSE,
	polarity));
	return 0;
	}

	static int aspeed_pwm_set_enable(struct udevice *dev, uint channel, bool enable)
	{
	struct aspeed_pwm_priv *priv = dev_get_priv(dev);

	if (channel >= PWM_ASPEED_NR_PWMS)
	return -EINVAL;

	regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL(channel),
	PWM_ASPEED_CTRL_PIN_ENABLE,
	enable ? PWM_ASPEED_CTRL_PIN_ENABLE : 0);
	return 0;
	}

	static int aspeed_pwm_set_config(struct udevice *dev, uint channel,
	uint period_ns, uint duty_ns)
	{
	struct aspeed_pwm_priv *priv = dev_get_priv(dev);
	u32 duty_pt;
	unsigned long rate;
	u64 div_h, div_l, divisor;
	bool clk_en;

	if (channel >= PWM_ASPEED_NR_PWMS)
	return -EINVAL;
	dev_dbg(dev, "expect period: %dns, duty_cycle: %dns\n", period_ns,
	duty_ns);

	rate = clk_get_rate(&priv->clk);
	/*
	* Pick the smallest value for div_h so that div_l can be the biggest
	* which results in a finer resolution near the target period value.
	*/
	divisor = (u64)NSEC_PER_SEC * (PWM_ASPEED_FIXED_PERIOD + 1) *
	(PWM_ASPEED_CTRL_CLK_DIV_L + 1);
	div_h = order_base_2(div64_u64((u64)rate * period_ns + divisor - 1, divisor));
	if (div_h > 0xf)
	div_h = 0xf;

	divisor = ((u64)NSEC_PER_SEC * (PWM_ASPEED_FIXED_PERIOD + 1)) << div_h;
	div_l = div64_u64((u64)rate * period_ns, divisor);

	if (div_l == 0)
	return -ERANGE;

	div_l -= 1;

	if (div_l > 255)
	div_l = 255;

	dev_dbg(dev, "clk source: %ld div_h %lld, div_l : %lld\n", rate, div_h,
	div_l);
	/* duty_pt = duty_cycle * (PERIOD + 1) / period */
	duty_pt = div64_u64(duty_ns * (u64)rate,
	(u64)NSEC_PER_SEC * (div_l + 1) << div_h);
	dev_dbg(dev, "duty_cycle = %d, duty_pt = %d\n", duty_ns,
	duty_pt);

	if (duty_pt == 0) {
	clk_en = 0;
	} else {
	clk_en = 1;
	if (duty_pt >= (PWM_ASPEED_FIXED_PERIOD + 1))
	duty_pt = 0;
	/*
	* Fixed DUTY_CYCLE_PERIOD to its max value to get a
	* fine-grained resolution for duty_cycle at the expense of a
	* coarser period resolution.
	*/
	regmap_update_bits(priv->regmap, PWM_ASPEED_DUTY_CYCLE(channel),
	PWM_ASPEED_DUTY_CYCLE_PERIOD \|
	PWM_ASPEED_DUTY_CYCLE_RISING_POINT \|
	PWM_ASPEED_DUTY_CYCLE_FALLING_POINT,
	FIELD_PREP(PWM_ASPEED_DUTY_CYCLE_PERIOD,
	PWM_ASPEED_FIXED_PERIOD) \|
	FIELD_PREP(PWM_ASPEED_DUTY_CYCLE_FALLING_POINT,
	duty_pt));
	}

	regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL(channel),
	PWM_ASPEED_CTRL_CLK_DIV_H \|
	PWM_ASPEED_CTRL_CLK_DIV_L \|
	PWM_ASPEED_CTRL_CLK_ENABLE,
	FIELD_PREP(PWM_ASPEED_CTRL_CLK_DIV_H, div_h) \|
	FIELD_PREP(PWM_ASPEED_CTRL_CLK_DIV_L, div_l) \|
	FIELD_PREP(PWM_ASPEED_CTRL_CLK_ENABLE, clk_en));
	return 0;
	}

	static int aspeed_pwm_probe(struct udevice *dev)
	{
	int ret;
	struct aspeed_pwm_priv *priv = dev_get_priv(dev);
	struct udevice *parent_dev = dev_get_parent(dev);

	priv->regmap = syscon_node_to_regmap(dev_ofnode(dev->parent));
	if (IS_ERR(priv->regmap)) {
	dev_err(dev, "Couldn't get regmap\n");
	return PTR_ERR(priv->regmap);
	}

	ret = clk_get_by_index(parent_dev, 0, &priv->clk);
	if (ret < 0) {
	dev_err(dev, "get clock failed\n");
	return ret;
	}

	ret = reset_get_by_index(parent_dev, 0, &priv->reset);
	if (ret) {
	dev_err(dev, "get reset failed\n");
	return ret;
	}
	ret = reset_deassert(&priv->reset);
	if (ret) {
	dev_err(dev, "cannot deassert reset control: %pe\n",
	ERR_PTR(ret));
	return ret;
	}

	return 0;
	}

	static int aspeed_pwm_remove(struct udevice *dev)
	{
	struct aspeed_pwm_priv *priv = dev_get_priv(dev);

	reset_assert(&priv->reset);

	return 0;
	}

	static const struct pwm_ops aspeed_pwm_ops = {
	.set_invert = aspeed_pwm_set_invert,
	.set_config = aspeed_pwm_set_config,
	.set_enable = aspeed_pwm_set_enable,
	};

	static const struct udevice_id aspeed_pwm_ids[] = {
	{ .compatible = "aspeed,ast2600-pwm" },
	{ }
	};

	U_BOOT_DRIVER(aspeed_pwm) = {
	.name = "aspeed_pwm",
	.id = UCLASS_PWM,
	.of_match = aspeed_pwm_ids,
	.ops = &aspeed_pwm_ops,
	.probe = aspeed_pwm_probe,
	.remove = aspeed_pwm_remove,
	.priv_auto = sizeof(struct aspeed_pwm_priv),
	};