drivers/clk/ti/clk-divider.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * TI divider clock support
  *
  * Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
  *
  * Loosely based on Linux kernel drivers/clk/ti/divider.c
  */

 #include <common.h>
 #include <clk.h>
 #include <clk-uclass.h>
 #include <div64.h>
 #include <dm.h>
 #include <dm/device_compat.h>
 #include <asm/io.h>
 #include <linux/clk-provider.h>
 #include <linux/kernel.h>
 #include <linux/log2.h>
 #include "clk.h"

 /*
  * The reverse of DIV_ROUND_UP: The maximum number which
  * divided by m is r
  */
 #define MULT_ROUND_UP(r, m) ((r) * (m) + (m) - 1)

 struct clk_ti_divider_priv {
 	struct clk parent;
 	struct clk_ti_reg reg;
 	const struct clk_div_table *table;
 	u8 shift;
 	u8 flags;
 	u8 div_flags;
 	s8 latch;
 	u16 min;
 	u16 max;
 	u16 mask;
 };

 static unsigned int _get_div(const struct clk_div_table *table, ulong flags,
 			     unsigned int val)
 {
 	if (flags & CLK_DIVIDER_ONE_BASED)
 		return val;

 	if (flags & CLK_DIVIDER_POWER_OF_TWO)
 		return 1 << val;

 	if (table)
 		return clk_divider_get_table_div(table, val);

 	return val + 1;
 }

 static unsigned int _get_val(const struct clk_div_table *table, ulong flags,
 			     unsigned int div)
 {
 	if (flags & CLK_DIVIDER_ONE_BASED)
 		return div;

 	if (flags & CLK_DIVIDER_POWER_OF_TWO)
 		return __ffs(div);

 	if (table)
 		return clk_divider_get_table_val(table, div);

 	return div - 1;
 }

 static int _div_round_up(const struct clk_div_table *table, ulong parent_rate,
 			 ulong rate)
 {
 	const struct clk_div_table *clkt;
 	int up = INT_MAX;
 	int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);

 	for (clkt = table; clkt->div; clkt++) {
 		if (clkt->div == div)
 			return clkt->div;
 		else if (clkt->div < div)
 			continue;

 		if ((clkt->div - div) < (up - div))
 			up = clkt->div;
 	}

 	return up;
 }

 static int _div_round(const struct clk_div_table *table, ulong parent_rate,
 		      ulong rate)
 {
 	if (table)
 		return _div_round_up(table, parent_rate, rate);

 	return DIV_ROUND_UP(parent_rate, rate);
 }

 static int clk_ti_divider_best_div(struct clk *clk, ulong rate,
 				   ulong *best_parent_rate)
 {
 	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);
 	ulong parent_rate, parent_round_rate, max_div;
 	ulong best_rate, r;
 	int i, best_div = 0;

 	parent_rate = clk_get_rate(&priv->parent);
 	if (IS_ERR_VALUE(parent_rate))
 		return parent_rate;

 	if (!rate)
 		rate = 1;

 	if (!(clk->flags & CLK_SET_RATE_PARENT)) {
 		best_div = _div_round(priv->table, parent_rate, rate);
 		if (best_div == 0)
 			best_div = 1;

 		if (best_div > priv->max)
 			best_div = priv->max;

 		*best_parent_rate = parent_rate;
 		return best_div;
 	}

 	max_div = min(ULONG_MAX / rate, (ulong)priv->max);
 	for (best_rate = 0, i = 1; i <= max_div; i++) {
 		if (!clk_divider_is_valid_div(priv->table, priv->div_flags, i))
 			continue;

 		/*
 		 * It's the most ideal case if the requested rate can be
 		 * divided from parent clock without needing to change
 		 * parent rate, so return the divider immediately.
 		 */
 		if ((rate * i) == parent_rate) {
 			*best_parent_rate = parent_rate;
 			dev_dbg(clk->dev, "rate=%ld, best_rate=%ld, div=%d\n",
 				rate, rate, i);
 			return i;
 		}

 		parent_round_rate = clk_round_rate(&priv->parent,
 						   MULT_ROUND_UP(rate, i));
 		if (IS_ERR_VALUE(parent_round_rate))
 			continue;

 		r = DIV_ROUND_UP(parent_round_rate, i);
 		if (r <= rate && r > best_rate) {
 			best_div = i;
 			best_rate = r;
 			*best_parent_rate = parent_round_rate;
 			if (best_rate == rate)
 				break;
 		}
 	}

 	if (best_div == 0) {
 		best_div = priv->max;
 		parent_round_rate = clk_round_rate(&priv->parent, 1);
 		if (IS_ERR_VALUE(parent_round_rate))
 			return parent_round_rate;
 	}

 	dev_dbg(clk->dev, "rate=%ld, best_rate=%ld, div=%d\n", rate, best_rate,
 		best_div);

 	return best_div;
 }

 static ulong clk_ti_divider_round_rate(struct clk *clk, ulong rate)
 {
 	ulong parent_rate;
 	int div;

 	div = clk_ti_divider_best_div(clk, rate, &parent_rate);
 	if (div < 0)
 		return div;

 	return DIV_ROUND_UP(parent_rate, div);
 }

 static ulong clk_ti_divider_set_rate(struct clk *clk, ulong rate)
 {
 	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);
 	ulong parent_rate;
 	int div;
 	u32 val, v;

 	div = clk_ti_divider_best_div(clk, rate, &parent_rate);
 	if (div < 0)
 		return div;

 	if (clk->flags & CLK_SET_RATE_PARENT) {
 		parent_rate = clk_set_rate(&priv->parent, parent_rate);
 		if (IS_ERR_VALUE(parent_rate))
 			return parent_rate;
 	}

 	val = _get_val(priv->table, priv->div_flags, div);

 	v = clk_ti_readl(&priv->reg);
 	v &= ~(priv->mask << priv->shift);
 	v |= val << priv->shift;
 	clk_ti_writel(v, &priv->reg);
 	clk_ti_latch(&priv->reg, priv->latch);

 	return clk_get_rate(clk);
 }

 static ulong clk_ti_divider_get_rate(struct clk *clk)
 {
 	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);
 	ulong rate, parent_rate;
 	unsigned int div;
 	u32 v;

 	parent_rate = clk_get_rate(&priv->parent);
 	if (IS_ERR_VALUE(parent_rate))
 		return parent_rate;

 	v = clk_ti_readl(&priv->reg) >> priv->shift;
 	v &= priv->mask;

 	div = _get_div(priv->table, priv->div_flags, v);
 	if (!div) {
 		if (!(priv->div_flags & CLK_DIVIDER_ALLOW_ZERO))
 			dev_warn(clk->dev,
 				 "zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n");
 		return parent_rate;
 	}

 	rate = DIV_ROUND_UP(parent_rate, div);
 	dev_dbg(clk->dev, "rate=%ld\n", rate);
 	return rate;
 }

 static int clk_ti_divider_request(struct clk *clk)
 {
 	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);

 	clk->flags = priv->flags;
 	return 0;
 }

 const struct clk_ops clk_ti_divider_ops = {
 	.request = clk_ti_divider_request,
 	.round_rate = clk_ti_divider_round_rate,
 	.get_rate = clk_ti_divider_get_rate,
 	.set_rate = clk_ti_divider_set_rate
 };

 static int clk_ti_divider_remove(struct udevice *dev)
 {
 	struct clk_ti_divider_priv *priv = dev_get_priv(dev);
 	int err;

 	err = clk_release_all(&priv->parent, 1);
 	if (err) {
 		dev_err(dev, "failed to release parent clock\n");
 		return err;
 	}

 	return 0;
 }

 static int clk_ti_divider_probe(struct udevice *dev)
 {
 	struct clk_ti_divider_priv *priv = dev_get_priv(dev);
 	int err;

 	err = clk_get_by_index(dev, 0, &priv->parent);
 	if (err) {
 		dev_err(dev, "failed to get parent clock\n");
 		return err;
 	}

 	return 0;
 }

 static int clk_ti_divider_of_to_plat(struct udevice *dev)
 {
 	struct clk_ti_divider_priv *priv = dev_get_priv(dev);
 	struct clk_div_table *table = NULL;
 	u32 val, valid_div;
 	u32 min_div = 0;
 	u32 max_val, max_div = 0;
 	u16 mask;
 	int i, div_num, err;

 	err = clk_ti_get_reg_addr(dev, 0, &priv->reg);
 	if (err) {
 		dev_err(dev, "failed to get register address\n");
 		return err;
 	}

 	priv->shift = dev_read_u32_default(dev, "ti,bit-shift", 0);
 	priv->latch = dev_read_s32_default(dev, "ti,latch-bit", -EINVAL);
 	if (dev_read_bool(dev, "ti,index-starts-at-one"))
 		priv->div_flags |= CLK_DIVIDER_ONE_BASED;

 	if (dev_read_bool(dev, "ti,index-power-of-two"))
 		priv->div_flags |= CLK_DIVIDER_POWER_OF_TWO;

 	if (dev_read_bool(dev, "ti,set-rate-parent"))
 		priv->flags |= CLK_SET_RATE_PARENT;

 	if (dev_read_prop(dev, "ti,dividers", &div_num)) {
 		div_num /= sizeof(u32);

 		/* Determine required size for divider table */
 		for (i = 0, valid_div = 0; i < div_num; i++) {
 			dev_read_u32_index(dev, "ti,dividers", i, &val);
 			if (val)
 				valid_div++;
 		}

 		if (!valid_div) {
 			dev_err(dev, "no valid dividers\n");
 			return -EINVAL;
 		}

 		table = calloc(valid_div + 1, sizeof(*table));
 		if (!table)
 			return -ENOMEM;

 		for (i = 0, valid_div = 0; i < div_num; i++) {
 			dev_read_u32_index(dev, "ti,dividers", i, &val);
 			if (!val)
 				continue;

 			table[valid_div].div = val;
 			table[valid_div].val = i;
 			valid_div++;
 			if (val > max_div)
 				max_div = val;

 			if (!min_div || val < min_div)
 				min_div = val;
 		}

 		max_val = max_div;
 	} else {
 		/* Divider table not provided, determine min/max divs */
 		min_div = dev_read_u32_default(dev, "ti,min-div", 1);
 		if (dev_read_u32(dev, "ti,max-div", &max_div)) {
 			dev_err(dev, "missing 'max-div' property\n");
 			return -EFAULT;
 		}

 		max_val = max_div;
 		if (!(priv->div_flags & CLK_DIVIDER_ONE_BASED) &&
 		    !(priv->div_flags & CLK_DIVIDER_POWER_OF_TWO))
 			max_val--;
 	}

 	priv->table = table;
 	priv->min = min_div;
 	priv->max = max_div;

 	if (priv->div_flags & CLK_DIVIDER_POWER_OF_TWO)
 		mask = fls(max_val) - 1;
 	else
 		mask = max_val;

 	priv->mask = (1 << fls(mask)) - 1;
 	return 0;
 }

 static const struct udevice_id clk_ti_divider_of_match[] = {
 	{.compatible = "ti,divider-clock"},
 	{}
 };

 U_BOOT_DRIVER(clk_ti_divider) = {
 	.name = "ti_divider_clock",
 	.id = UCLASS_CLK,
 	.of_match = clk_ti_divider_of_match,
 	.of_to_plat = clk_ti_divider_of_to_plat,
 	.probe = clk_ti_divider_probe,
 	.remove = clk_ti_divider_remove,
 	.priv_auto = sizeof(struct clk_ti_divider_priv),
 	.ops = &clk_ti_divider_ops,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* TI divider clock support
	*
	* Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
	*
	* Loosely based on Linux kernel drivers/clk/ti/divider.c
	*/

	#include <common.h>
	#include <clk.h>
	#include <clk-uclass.h>
	#include <div64.h>
	#include <dm.h>
	#include <dm/device_compat.h>
	#include <asm/io.h>
	#include <linux/clk-provider.h>
	#include <linux/kernel.h>
	#include <linux/log2.h>
	#include "clk.h"

	/*
	* The reverse of DIV_ROUND_UP: The maximum number which
	* divided by m is r
	*/
	#define MULT_ROUND_UP(r, m) ((r) * (m) + (m) - 1)

	struct clk_ti_divider_priv {
	struct clk parent;
	struct clk_ti_reg reg;
	const struct clk_div_table *table;
	u8 shift;
	u8 flags;
	u8 div_flags;
	s8 latch;
	u16 min;
	u16 max;
	u16 mask;
	};

	static unsigned int _get_div(const struct clk_div_table *table, ulong flags,
	unsigned int val)
	{
	if (flags & CLK_DIVIDER_ONE_BASED)
	return val;

	if (flags & CLK_DIVIDER_POWER_OF_TWO)
	return 1 << val;

	if (table)
	return clk_divider_get_table_div(table, val);

	return val + 1;
	}

	static unsigned int _get_val(const struct clk_div_table *table, ulong flags,
	unsigned int div)
	{
	if (flags & CLK_DIVIDER_ONE_BASED)
	return div;

	if (flags & CLK_DIVIDER_POWER_OF_TWO)
	return __ffs(div);

	if (table)
	return clk_divider_get_table_val(table, div);

	return div - 1;
	}

	static int _div_round_up(const struct clk_div_table *table, ulong parent_rate,
	ulong rate)
	{
	const struct clk_div_table *clkt;
	int up = INT_MAX;
	int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);

	for (clkt = table; clkt->div; clkt++) {
	if (clkt->div == div)
	return clkt->div;
	else if (clkt->div < div)
	continue;

	if ((clkt->div - div) < (up - div))
	up = clkt->div;
	}

	return up;
	}

	static int _div_round(const struct clk_div_table *table, ulong parent_rate,
	ulong rate)
	{
	if (table)
	return _div_round_up(table, parent_rate, rate);

	return DIV_ROUND_UP(parent_rate, rate);
	}

	static int clk_ti_divider_best_div(struct clk *clk, ulong rate,
	ulong *best_parent_rate)
	{
	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);
	ulong parent_rate, parent_round_rate, max_div;
	ulong best_rate, r;
	int i, best_div = 0;

	parent_rate = clk_get_rate(&priv->parent);
	if (IS_ERR_VALUE(parent_rate))
	return parent_rate;

	if (!rate)
	rate = 1;

	if (!(clk->flags & CLK_SET_RATE_PARENT)) {
	best_div = _div_round(priv->table, parent_rate, rate);
	if (best_div == 0)
	best_div = 1;

	if (best_div > priv->max)
	best_div = priv->max;

	*best_parent_rate = parent_rate;
	return best_div;
	}

	max_div = min(ULONG_MAX / rate, (ulong)priv->max);
	for (best_rate = 0, i = 1; i <= max_div; i++) {
	if (!clk_divider_is_valid_div(priv->table, priv->div_flags, i))
	continue;

	/*
	* It's the most ideal case if the requested rate can be
	* divided from parent clock without needing to change
	* parent rate, so return the divider immediately.
	*/
	if ((rate * i) == parent_rate) {
	*best_parent_rate = parent_rate;
	dev_dbg(clk->dev, "rate=%ld, best_rate=%ld, div=%d\n",
	rate, rate, i);
	return i;
	}

	parent_round_rate = clk_round_rate(&priv->parent,
	MULT_ROUND_UP(rate, i));
	if (IS_ERR_VALUE(parent_round_rate))
	continue;

	r = DIV_ROUND_UP(parent_round_rate, i);
	if (r <= rate && r > best_rate) {
	best_div = i;
	best_rate = r;
	*best_parent_rate = parent_round_rate;
	if (best_rate == rate)
	break;
	}
	}

	if (best_div == 0) {
	best_div = priv->max;
	parent_round_rate = clk_round_rate(&priv->parent, 1);
	if (IS_ERR_VALUE(parent_round_rate))
	return parent_round_rate;
	}

	dev_dbg(clk->dev, "rate=%ld, best_rate=%ld, div=%d\n", rate, best_rate,
	best_div);

	return best_div;
	}

	static ulong clk_ti_divider_round_rate(struct clk *clk, ulong rate)
	{
	ulong parent_rate;
	int div;

	div = clk_ti_divider_best_div(clk, rate, &parent_rate);
	if (div < 0)
	return div;

	return DIV_ROUND_UP(parent_rate, div);
	}

	static ulong clk_ti_divider_set_rate(struct clk *clk, ulong rate)
	{
	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);
	ulong parent_rate;
	int div;
	u32 val, v;

	div = clk_ti_divider_best_div(clk, rate, &parent_rate);
	if (div < 0)
	return div;

	if (clk->flags & CLK_SET_RATE_PARENT) {
	parent_rate = clk_set_rate(&priv->parent, parent_rate);
	if (IS_ERR_VALUE(parent_rate))
	return parent_rate;
	}

	val = _get_val(priv->table, priv->div_flags, div);

	v = clk_ti_readl(&priv->reg);
	v &= ~(priv->mask << priv->shift);
	v \|= val << priv->shift;
	clk_ti_writel(v, &priv->reg);
	clk_ti_latch(&priv->reg, priv->latch);

	return clk_get_rate(clk);
	}

	static ulong clk_ti_divider_get_rate(struct clk *clk)
	{
	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);
	ulong rate, parent_rate;
	unsigned int div;
	u32 v;

	parent_rate = clk_get_rate(&priv->parent);
	if (IS_ERR_VALUE(parent_rate))
	return parent_rate;

	v = clk_ti_readl(&priv->reg) >> priv->shift;
	v &= priv->mask;

	div = _get_div(priv->table, priv->div_flags, v);
	if (!div) {
	if (!(priv->div_flags & CLK_DIVIDER_ALLOW_ZERO))
	dev_warn(clk->dev,
	"zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n");
	return parent_rate;
	}

	rate = DIV_ROUND_UP(parent_rate, div);
	dev_dbg(clk->dev, "rate=%ld\n", rate);
	return rate;
	}

	static int clk_ti_divider_request(struct clk *clk)
	{
	struct clk_ti_divider_priv *priv = dev_get_priv(clk->dev);

	clk->flags = priv->flags;
	return 0;
	}

	const struct clk_ops clk_ti_divider_ops = {
	.request = clk_ti_divider_request,
	.round_rate = clk_ti_divider_round_rate,
	.get_rate = clk_ti_divider_get_rate,
	.set_rate = clk_ti_divider_set_rate
	};

	static int clk_ti_divider_remove(struct udevice *dev)
	{
	struct clk_ti_divider_priv *priv = dev_get_priv(dev);
	int err;

	err = clk_release_all(&priv->parent, 1);
	if (err) {
	dev_err(dev, "failed to release parent clock\n");
	return err;
	}

	return 0;
	}

	static int clk_ti_divider_probe(struct udevice *dev)
	{
	struct clk_ti_divider_priv *priv = dev_get_priv(dev);
	int err;

	err = clk_get_by_index(dev, 0, &priv->parent);
	if (err) {
	dev_err(dev, "failed to get parent clock\n");
	return err;
	}

	return 0;
	}

	static int clk_ti_divider_of_to_plat(struct udevice *dev)
	{
	struct clk_ti_divider_priv *priv = dev_get_priv(dev);
	struct clk_div_table *table = NULL;
	u32 val, valid_div;
	u32 min_div = 0;
	u32 max_val, max_div = 0;
	u16 mask;
	int i, div_num, err;

	err = clk_ti_get_reg_addr(dev, 0, &priv->reg);
	if (err) {
	dev_err(dev, "failed to get register address\n");
	return err;
	}

	priv->shift = dev_read_u32_default(dev, "ti,bit-shift", 0);
	priv->latch = dev_read_s32_default(dev, "ti,latch-bit", -EINVAL);
	if (dev_read_bool(dev, "ti,index-starts-at-one"))
	priv->div_flags \|= CLK_DIVIDER_ONE_BASED;

	if (dev_read_bool(dev, "ti,index-power-of-two"))
	priv->div_flags \|= CLK_DIVIDER_POWER_OF_TWO;

	if (dev_read_bool(dev, "ti,set-rate-parent"))
	priv->flags \|= CLK_SET_RATE_PARENT;

	if (dev_read_prop(dev, "ti,dividers", &div_num)) {
	div_num /= sizeof(u32);

	/* Determine required size for divider table */
	for (i = 0, valid_div = 0; i < div_num; i++) {
	dev_read_u32_index(dev, "ti,dividers", i, &val);
	if (val)
	valid_div++;
	}

	if (!valid_div) {
	dev_err(dev, "no valid dividers\n");
	return -EINVAL;
	}

	table = calloc(valid_div + 1, sizeof(*table));
	if (!table)
	return -ENOMEM;

	for (i = 0, valid_div = 0; i < div_num; i++) {
	dev_read_u32_index(dev, "ti,dividers", i, &val);
	if (!val)
	continue;

	table[valid_div].div = val;
	table[valid_div].val = i;
	valid_div++;
	if (val > max_div)
	max_div = val;

	if (!min_div \|\| val < min_div)
	min_div = val;
	}

	max_val = max_div;
	} else {
	/* Divider table not provided, determine min/max divs */
	min_div = dev_read_u32_default(dev, "ti,min-div", 1);
	if (dev_read_u32(dev, "ti,max-div", &max_div)) {
	dev_err(dev, "missing 'max-div' property\n");
	return -EFAULT;
	}

	max_val = max_div;
	if (!(priv->div_flags & CLK_DIVIDER_ONE_BASED) &&
	!(priv->div_flags & CLK_DIVIDER_POWER_OF_TWO))
	max_val--;
	}

	priv->table = table;
	priv->min = min_div;
	priv->max = max_div;

	if (priv->div_flags & CLK_DIVIDER_POWER_OF_TWO)
	mask = fls(max_val) - 1;
	else
	mask = max_val;

	priv->mask = (1 << fls(mask)) - 1;
	return 0;
	}

	static const struct udevice_id clk_ti_divider_of_match[] = {
	{.compatible = "ti,divider-clock"},
	{}
	};

	U_BOOT_DRIVER(clk_ti_divider) = {
	.name = "ti_divider_clock",
	.id = UCLASS_CLK,
	.of_match = clk_ti_divider_of_match,
	.of_to_plat = clk_ti_divider_of_to_plat,
	.probe = clk_ti_divider_probe,
	.remove = clk_ti_divider_remove,
	.priv_auto = sizeof(struct clk_ti_divider_priv),
	.ops = &clk_ti_divider_ops,
	};