drivers/pwm/pwm-meson.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * Copyright (C) 2020 BayLibre, SAS.
 * Author: Neil Armstrong <narmstrong@baylibre.com>
 * Copyright (C) 2014 Amlogic, Inc.
 *
 * This PWM is only a set of Gates, Dividers and Counters:
 * PWM output is achieved by calculating a clock that permits calculating
 * two periods (low and high). The counter then has to be set to switch after
 * N cycles for the first half period.
 * The hardware has no "polarity" setting. This driver reverses the period
 * cycles (the low length is inverted with the high length) for
 * PWM_POLARITY_INVERSED.
 * Setting the polarity will disable and re-enable the PWM output.
 * Disabling the PWM stops the output immediately (without waiting for the
 * current period to complete first).
 */

#include <clk.h>
#include <div64.h>
#include <dm.h>
#include <pwm.h>
#include <regmap.h>
#include <linux/io.h>
#include <linux/math64.h>
#include <linux/bitfield.h>
#include <linux/clk-provider.h>
#include <linux/time.h>

#define REG_PWM_A		0x0
#define REG_PWM_B		0x4
#define PWM_LOW_MASK		GENMASK(15, 0)
#define PWM_HIGH_MASK		GENMASK(31, 16)

#define REG_MISC_AB		0x8
#define MISC_B_CLK_EN		BIT(23)
#define MISC_A_CLK_EN		BIT(15)
#define MISC_CLK_DIV_MASK	0x7f
#define MISC_B_CLK_DIV_SHIFT	16
#define MISC_A_CLK_DIV_SHIFT	8
#define MISC_B_CLK_SEL_SHIFT	6
#define MISC_A_CLK_SEL_SHIFT	4
#define MISC_CLK_SEL_MASK	0x3
#define MISC_B_EN		BIT(1)
#define MISC_A_EN		BIT(0)

#define MESON_NUM_PWMS		2

static struct meson_pwm_channel_data {
	u8		reg_offset;
	u8		clk_sel_shift;
	u8		clk_div_shift;
	u32		clk_en_mask;
	u32		pwm_en_mask;
} meson_pwm_per_channel_data[MESON_NUM_PWMS] = {
	{
		.reg_offset	= REG_PWM_A,
		.clk_sel_shift	= MISC_A_CLK_SEL_SHIFT,
		.clk_div_shift	= MISC_A_CLK_DIV_SHIFT,
		.clk_en_mask	= MISC_A_CLK_EN,
		.pwm_en_mask	= MISC_A_EN,
	},
	{
		.reg_offset	= REG_PWM_B,
		.clk_sel_shift	= MISC_B_CLK_SEL_SHIFT,
		.clk_div_shift	= MISC_B_CLK_DIV_SHIFT,
		.clk_en_mask	= MISC_B_CLK_EN,
		.pwm_en_mask	= MISC_B_EN,
	}
};

struct meson_pwm_channel {
	unsigned int hi;
	unsigned int lo;
	u8 pre_div;
	uint period_ns;
	uint duty_ns;
	bool configured;
	bool enabled;
	bool polarity;
	struct clk clk;
};

struct meson_pwm_data {
	const long *parent_ids;
	unsigned int num_parents;
};

struct meson_pwm {
	const struct meson_pwm_data *data;
	struct meson_pwm_channel channels[MESON_NUM_PWMS];
	void __iomem *base;
};

static int meson_pwm_set_enable(struct udevice *dev, uint channel, bool enable);

static int meson_pwm_set_config(struct udevice *dev, uint channeln,
				 uint period_ns, uint duty_ns)
{
	struct meson_pwm *priv = dev_get_priv(dev);
	struct meson_pwm_channel *channel;
	struct meson_pwm_channel_data *channel_data;
	unsigned int duty, period, pre_div, cnt, duty_cnt;
	unsigned long fin_freq;

	if (channeln >= MESON_NUM_PWMS)
		return -ENODEV;

	channel = &priv->channels[channeln];
	channel_data = &meson_pwm_per_channel_data[channeln];

	period = period_ns;
	if (channel->polarity)
		duty = period_ns - duty_ns;
	else
		duty = duty_ns;

	debug("%s%d: polarity %s duty %d period %d\n", __func__, channeln,
	      channel->polarity ? "true" : "false", duty, period);

	fin_freq = clk_get_rate(&channel->clk);
	if (fin_freq == 0) {
		printf("%s%d: invalid source clock frequency\n", __func__, channeln);
		return -EINVAL;
	}

	debug("%s%d: fin_freq: %lu Hz\n", __func__, channeln, fin_freq);

	pre_div = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * 0xffffLL);
	if (pre_div > MISC_CLK_DIV_MASK) {
		printf("%s%d: unable to get period pre_div\n", __func__, channeln);
		return -EINVAL;
	}

	cnt = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * (pre_div + 1));
	if (cnt > 0xffff) {
		printf("%s%d: unable to get period cnt\n", __func__, channeln);
		return -EINVAL;
	}

	debug("%s%d: period=%u pre_div=%u cnt=%u\n", __func__, channeln, period, pre_div, cnt);

	if (duty == period) {
		channel->pre_div = pre_div;
		channel->hi = cnt;
		channel->lo = 0;
	} else if (duty == 0) {
		channel->pre_div = pre_div;
		channel->hi = 0;
		channel->lo = cnt;
	} else {
		/* Then check is we can have the duty with the same pre_div */
		duty_cnt = div64_u64(fin_freq * (u64)duty, NSEC_PER_SEC * (pre_div + 1));
		if (duty_cnt > 0xffff) {
			printf("%s%d: unable to get duty cycle\n", __func__, channeln);
			return -EINVAL;
		}

		debug("%s%d: duty=%u pre_div=%u duty_cnt=%u\n",
		      __func__, channeln, duty, pre_div, duty_cnt);

		channel->pre_div = pre_div;
		channel->hi = duty_cnt;
		channel->lo = cnt - duty_cnt;
	}

	channel->period_ns = period_ns;
	channel->duty_ns = duty_ns;
	channel->configured = true;

	if (channel->enabled) {
		meson_pwm_set_enable(dev, channeln, false);
		meson_pwm_set_enable(dev, channeln, true);
	}

	return 0;
}

static int meson_pwm_set_enable(struct udevice *dev, uint channeln, bool enable)
{
	struct meson_pwm *priv = dev_get_priv(dev);
	struct meson_pwm_channel *channel;
	struct meson_pwm_channel_data *channel_data;
	u32 value;

	if (channeln >= MESON_NUM_PWMS)
		return -ENODEV;

	channel = &priv->channels[channeln];
	channel_data = &meson_pwm_per_channel_data[channeln];

	if (!channel->configured)
		return -EINVAL;

	if (enable) {
		if (channel->enabled)
			return 0;

		value = readl(priv->base + REG_MISC_AB);
		value &= ~(MISC_CLK_DIV_MASK << channel_data->clk_div_shift);
		value |= channel->pre_div << channel_data->clk_div_shift;
		value |= channel_data->clk_en_mask;
		writel(value, priv->base + REG_MISC_AB);

		value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) |
			FIELD_PREP(PWM_LOW_MASK, channel->lo);
		writel(value, priv->base + channel_data->reg_offset);

		value = readl(priv->base + REG_MISC_AB);
		value |= channel_data->pwm_en_mask;
		writel(value, priv->base + REG_MISC_AB);

		debug("%s%d: enabled\n", __func__, channeln);
		channel->enabled = true;
	} else {
		if (!channel->enabled)
			return 0;

		value = readl(priv->base + REG_MISC_AB);
		value &= channel_data->pwm_en_mask;
		writel(value, priv->base + REG_MISC_AB);

		debug("%s%d: disabled\n", __func__, channeln);
		channel->enabled = false;
	}

	return 0;
}

static int meson_pwm_set_invert(struct udevice *dev, uint channeln, bool polarity)
{
	struct meson_pwm *priv = dev_get_priv(dev);
	struct meson_pwm_channel *channel;

	if (channeln >= MESON_NUM_PWMS)
		return -ENODEV;

	debug("%s%d: set invert %s\n", __func__, channeln, polarity ? "true" : "false");

	channel = &priv->channels[channeln];

	channel->polarity = polarity;

	if (!channel->configured)
		return 0;

	return meson_pwm_set_config(dev, channeln, channel->period_ns, channel->duty_ns);
}

static int meson_pwm_of_to_plat(struct udevice *dev)
{
	struct meson_pwm *priv = dev_get_priv(dev);

	priv->base = dev_read_addr_ptr(dev);

	return 0;
}

static int meson_pwm_probe(struct udevice *dev)
{
	struct meson_pwm *priv = dev_get_priv(dev);
	struct meson_pwm_data *data;
	unsigned int i, p;
	char name[255];
	int err;
	u32 reg;

	data = (struct meson_pwm_data *)dev_get_driver_data(dev);
	if (!data)
		return -EINVAL;

	for (i = 0; i < MESON_NUM_PWMS; i++) {
		struct meson_pwm_channel *channel = &priv->channels[i];
		struct meson_pwm_channel_data *channel_data = &meson_pwm_per_channel_data[i];

		snprintf(name, sizeof(name), "clkin%u", i);

		err = clk_get_by_name(dev, name, &channel->clk);
		/* If clock is not specified, use the already set clock */
		if (err == -ENODATA) {
			struct udevice *cdev;
			struct uclass *uc;

			/* Get parent from mux */
			p = (readl(priv->base + REG_MISC_AB) >> channel_data->clk_sel_shift) &
				MISC_CLK_SEL_MASK;

			if (p >= data->num_parents) {
				printf("%s%d: hw parent is invalid\n", __func__, i);
				return -EINVAL;
			}

			if (data->parent_ids[p] == -1) {
				/* Search for xtal clk */
				const char *str;

				err = uclass_get(UCLASS_CLK, &uc);
				if (err)
					return err;

				uclass_foreach_dev(cdev, uc) {
					if (strcmp(cdev->driver->name, "fixed_rate_clock"))
						continue;

					str = ofnode_read_string(dev_ofnode(cdev),
								 "clock-output-names");
					if (!str)
						continue;

					if (!strcmp(str, "xtal")) {
						err = uclass_get_device_by_ofnode(UCLASS_CLK,
										  dev_ofnode(cdev),
										  &cdev);
						if (err) {
							printf("%s%d: Failed to get xtal clk\n", __func__, i);
							return err;
						}

						break;
					}
				}

				if (!cdev) {
					printf("%s%d: Failed to find xtal clk device\n", __func__, i);
					return -EINVAL;
				}

				channel->clk.dev = cdev;
				channel->clk.id = 0;
				channel->clk.data = 0;
			} else {
				/* Look for parent clock */
				err = uclass_get(UCLASS_CLK, &uc);
				if (err)
					return err;

				uclass_foreach_dev(cdev, uc) {
					if (strstr(cdev->driver->name, "meson_clk"))
						break;
				}

				if (!cdev) {
					printf("%s%d: Failed to find clk device\n", __func__, i);
					return -EINVAL;
				}

				err = uclass_get_device_by_ofnode(UCLASS_CLK,
								  dev_ofnode(cdev),
								  &cdev);
				if (err) {
					printf("%s%d: Failed to get clk controller\n", __func__, i);
					return err;
				}

				channel->clk.dev = cdev;
				channel->clk.id = data->parent_ids[p];
				channel->clk.data = 0;
			}

			/* We have our source clock, do not alter HW clock mux */
			continue;
		} else
			return err;

		/* Get id in list */
		for (p = 0 ; p < data->num_parents ; ++p) {
			if (!strcmp(channel->clk.dev->driver->name, "fixed_rate_clock")) {
				if (data->parent_ids[p] == -1)
					break;
			} else {
				if (data->parent_ids[p] == channel->clk.id)
					break;
			}
		}

		/* Invalid clock ID */
		if (p == data->num_parents) {
			printf("%s%d: source clock is invalid\n", __func__, i);
			return -EINVAL;
		}

		/* switch parent in mux */
		reg = readl(priv->base + REG_MISC_AB);

		debug("%s%d: switching parent %d to %d\n", __func__, i,
		      (reg >> channel_data->clk_sel_shift) & MISC_CLK_SEL_MASK, p);

		reg &= MISC_CLK_SEL_MASK << channel_data->clk_sel_shift;
		reg |= (p & MISC_CLK_SEL_MASK) << channel_data->clk_sel_shift;
		writel(reg, priv->base + REG_MISC_AB);
	}

	return 0;
}

static const struct pwm_ops meson_pwm_ops = {
	.set_config	= meson_pwm_set_config,
	.set_enable	= meson_pwm_set_enable,
	.set_invert	= meson_pwm_set_invert,
};

#define XTAL			-1

/* Local clock ids aliases to avoid define conflicts */
#define GXBB_CLKID_HDMI_PLL		2
#define GXBB_CLKID_FCLK_DIV3		5
#define GXBB_CLKID_FCLK_DIV4		6
#define GXBB_CLKID_CLK81		12

static const long pwm_gxbb_parent_ids[] = {
	XTAL, GXBB_CLKID_HDMI_PLL, GXBB_CLKID_FCLK_DIV4, GXBB_CLKID_FCLK_DIV3
};

static const struct meson_pwm_data pwm_gxbb_data = {
	.parent_ids = pwm_gxbb_parent_ids,
	.num_parents = ARRAY_SIZE(pwm_gxbb_parent_ids),
};

/*
 * Only the 2 first inputs of the GXBB AO PWMs are valid
 * The last 2 are grounded
 */
static const long pwm_gxbb_ao_parent_ids[] = {
	XTAL, GXBB_CLKID_CLK81
};

static const struct meson_pwm_data pwm_gxbb_ao_data = {
	.parent_ids = pwm_gxbb_ao_parent_ids,
	.num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_ids),
};

/* Local clock ids aliases to avoid define conflicts */
#define AXG_CLKID_FCLK_DIV3		3
#define AXG_CLKID_FCLK_DIV4		4
#define AXG_CLKID_FCLK_DIV5		5
#define AXG_CLKID_CLK81			10

static const long pwm_axg_ee_parent_ids[] = {
	XTAL, AXG_CLKID_FCLK_DIV5, AXG_CLKID_FCLK_DIV4, AXG_CLKID_FCLK_DIV3
};

static const struct meson_pwm_data pwm_axg_ee_data = {
	.parent_ids = pwm_axg_ee_parent_ids,
	.num_parents = ARRAY_SIZE(pwm_axg_ee_parent_ids),
};

static const long pwm_axg_ao_parent_ids[] = {
	AXG_CLKID_CLK81, XTAL, AXG_CLKID_FCLK_DIV4, AXG_CLKID_FCLK_DIV5
};

static const struct meson_pwm_data pwm_axg_ao_data = {
	.parent_ids = pwm_axg_ao_parent_ids,
	.num_parents = ARRAY_SIZE(pwm_axg_ao_parent_ids),
};

/* Local clock ids aliases to avoid define conflicts */
#define G12A_CLKID_FCLK_DIV3		3
#define G12A_CLKID_FCLK_DIV4		4
#define G12A_CLKID_FCLK_DIV5		5
#define G12A_CLKID_CLK81		10
#define G12A_CLKID_HDMI_PLL		128

static const long pwm_g12a_ao_ab_parent_ids[] = {
	XTAL, G12A_CLKID_CLK81, G12A_CLKID_FCLK_DIV4, G12A_CLKID_FCLK_DIV5
};

static const struct meson_pwm_data pwm_g12a_ao_ab_data = {
	.parent_ids = pwm_g12a_ao_ab_parent_ids,
	.num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_ids),
};

static const long pwm_g12a_ao_cd_parent_ids[] = {
	XTAL, G12A_CLKID_CLK81,
};

static const struct meson_pwm_data pwm_g12a_ao_cd_data = {
	.parent_ids = pwm_g12a_ao_cd_parent_ids,
	.num_parents = ARRAY_SIZE(pwm_g12a_ao_cd_parent_ids),
};

static const long pwm_g12a_ee_parent_ids[] = {
	XTAL, G12A_CLKID_HDMI_PLL, G12A_CLKID_FCLK_DIV4, G12A_CLKID_FCLK_DIV3
};

static const struct meson_pwm_data pwm_g12a_ee_data = {
	.parent_ids = pwm_g12a_ee_parent_ids,
	.num_parents = ARRAY_SIZE(pwm_g12a_ee_parent_ids),
};

static const struct udevice_id meson_pwm_ids[] = {
	{
		.compatible = "amlogic,meson-gxbb-pwm",
		.data = (ulong)&pwm_gxbb_data
	},
	{
		.compatible = "amlogic,meson-gxbb-ao-pwm",
		.data = (ulong)&pwm_gxbb_ao_data
	},
	{
		.compatible = "amlogic,meson-axg-ee-pwm",
		.data = (ulong)&pwm_axg_ee_data
	},
	{
		.compatible = "amlogic,meson-axg-ao-pwm",
		.data = (ulong)&pwm_axg_ao_data
	},
	{
		.compatible = "amlogic,meson-g12a-ee-pwm",
		.data = (ulong)&pwm_g12a_ee_data
	},
	{
		.compatible = "amlogic,meson-g12a-ao-pwm-ab",
		.data = (ulong)&pwm_g12a_ao_ab_data
	},
	{
		.compatible = "amlogic,meson-g12a-ao-pwm-cd",
		.data = (ulong)&pwm_g12a_ao_cd_data
	},
};

U_BOOT_DRIVER(meson_pwm) = {
	.name	= "meson_pwm",
	.id	= UCLASS_PWM,
	.of_match = meson_pwm_ids,
	.ops	= &meson_pwm_ops,
	.of_to_plat = meson_pwm_of_to_plat,
	.probe	 = meson_pwm_probe,
	.priv_auto	= sizeof(struct meson_pwm),
};