linux/drivers/clk/clk-divider.c
Stephen Boyd ff25881713 clk: divider: Add support for specifying parents via DT/pointers
After commit fc0c209c14 ("clk: Allow parents to be specified without
string names") we can use DT or direct clk_hw pointers to specify
parents. Create a generic function that shouldn't be used very often to
encode the multitude of ways of registering a divider clk with different
parent information. Then add a bunch of wrapper macros that only pass
down what needs to be passed down to the generic function to support
this with less arguments.

Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20190830150923.259497-13-sboyd@kernel.org
[sboyd@kernel.org: Export __clk_hw_register_divider]
2020-01-07 23:08:02 -08:00

581 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
* Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
* Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
*
* Adjustable divider clock implementation
*/
#include <linux/clk-provider.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/log2.h>
/*
* DOC: basic adjustable divider clock that cannot gate
*
* Traits of this clock:
* prepare - clk_prepare only ensures that parents are prepared
* enable - clk_enable only ensures that parents are enabled
* rate - rate is adjustable. clk->rate = ceiling(parent->rate / divisor)
* parent - fixed parent. No clk_set_parent support
*/
static inline u32 clk_div_readl(struct clk_divider *divider)
{
if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
return ioread32be(divider->reg);
return readl(divider->reg);
}
static inline void clk_div_writel(struct clk_divider *divider, u32 val)
{
if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
iowrite32be(val, divider->reg);
else
writel(val, divider->reg);
}
static unsigned int _get_table_maxdiv(const struct clk_div_table *table,
u8 width)
{
unsigned int maxdiv = 0, mask = clk_div_mask(width);
const struct clk_div_table *clkt;
for (clkt = table; clkt->div; clkt++)
if (clkt->div > maxdiv && clkt->val <= mask)
maxdiv = clkt->div;
return maxdiv;
}
static unsigned int _get_table_mindiv(const struct clk_div_table *table)
{
unsigned int mindiv = UINT_MAX;
const struct clk_div_table *clkt;
for (clkt = table; clkt->div; clkt++)
if (clkt->div < mindiv)
mindiv = clkt->div;
return mindiv;
}
static unsigned int _get_maxdiv(const struct clk_div_table *table, u8 width,
unsigned long flags)
{
if (flags & CLK_DIVIDER_ONE_BASED)
return clk_div_mask(width);
if (flags & CLK_DIVIDER_POWER_OF_TWO)
return 1 << clk_div_mask(width);
if (table)
return _get_table_maxdiv(table, width);
return clk_div_mask(width) + 1;
}
static unsigned int _get_table_div(const struct clk_div_table *table,
unsigned int val)
{
const struct clk_div_table *clkt;
for (clkt = table; clkt->div; clkt++)
if (clkt->val == val)
return clkt->div;
return 0;
}
static unsigned int _get_div(const struct clk_div_table *table,
unsigned int val, unsigned long flags, u8 width)
{
if (flags & CLK_DIVIDER_ONE_BASED)
return val;
if (flags & CLK_DIVIDER_POWER_OF_TWO)
return 1 << val;
if (flags & CLK_DIVIDER_MAX_AT_ZERO)
return val ? val : clk_div_mask(width) + 1;
if (table)
return _get_table_div(table, val);
return val + 1;
}
static unsigned int _get_table_val(const struct clk_div_table *table,
unsigned int div)
{
const struct clk_div_table *clkt;
for (clkt = table; clkt->div; clkt++)
if (clkt->div == div)
return clkt->val;
return 0;
}
static unsigned int _get_val(const struct clk_div_table *table,
unsigned int div, unsigned long flags, u8 width)
{
if (flags & CLK_DIVIDER_ONE_BASED)
return div;
if (flags & CLK_DIVIDER_POWER_OF_TWO)
return __ffs(div);
if (flags & CLK_DIVIDER_MAX_AT_ZERO)
return (div == clk_div_mask(width) + 1) ? 0 : div;
if (table)
return _get_table_val(table, div);
return div - 1;
}
unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
unsigned int val,
const struct clk_div_table *table,
unsigned long flags, unsigned long width)
{
unsigned int div;
div = _get_div(table, val, flags, width);
if (!div) {
WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
"%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
clk_hw_get_name(hw));
return parent_rate;
}
return DIV_ROUND_UP_ULL((u64)parent_rate, div);
}
EXPORT_SYMBOL_GPL(divider_recalc_rate);
static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_divider *divider = to_clk_divider(hw);
unsigned int val;
val = clk_div_readl(divider) >> divider->shift;
val &= clk_div_mask(divider->width);
return divider_recalc_rate(hw, parent_rate, val, divider->table,
divider->flags, divider->width);
}
static bool _is_valid_table_div(const struct clk_div_table *table,
unsigned int div)
{
const struct clk_div_table *clkt;
for (clkt = table; clkt->div; clkt++)
if (clkt->div == div)
return true;
return false;
}
static bool _is_valid_div(const struct clk_div_table *table, unsigned int div,
unsigned long flags)
{
if (flags & CLK_DIVIDER_POWER_OF_TWO)
return is_power_of_2(div);
if (table)
return _is_valid_table_div(table, div);
return true;
}
static int _round_up_table(const struct clk_div_table *table, int div)
{
const struct clk_div_table *clkt;
int up = INT_MAX;
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 _round_down_table(const struct clk_div_table *table, int div)
{
const struct clk_div_table *clkt;
int down = _get_table_mindiv(table);
for (clkt = table; clkt->div; clkt++) {
if (clkt->div == div)
return clkt->div;
else if (clkt->div > div)
continue;
if ((div - clkt->div) < (div - down))
down = clkt->div;
}
return down;
}
static int _div_round_up(const struct clk_div_table *table,
unsigned long parent_rate, unsigned long rate,
unsigned long flags)
{
int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
if (flags & CLK_DIVIDER_POWER_OF_TWO)
div = __roundup_pow_of_two(div);
if (table)
div = _round_up_table(table, div);
return div;
}
static int _div_round_closest(const struct clk_div_table *table,
unsigned long parent_rate, unsigned long rate,
unsigned long flags)
{
int up, down;
unsigned long up_rate, down_rate;
up = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
down = parent_rate / rate;
if (flags & CLK_DIVIDER_POWER_OF_TWO) {
up = __roundup_pow_of_two(up);
down = __rounddown_pow_of_two(down);
} else if (table) {
up = _round_up_table(table, up);
down = _round_down_table(table, down);
}
up_rate = DIV_ROUND_UP_ULL((u64)parent_rate, up);
down_rate = DIV_ROUND_UP_ULL((u64)parent_rate, down);
return (rate - up_rate) <= (down_rate - rate) ? up : down;
}
static int _div_round(const struct clk_div_table *table,
unsigned long parent_rate, unsigned long rate,
unsigned long flags)
{
if (flags & CLK_DIVIDER_ROUND_CLOSEST)
return _div_round_closest(table, parent_rate, rate, flags);
return _div_round_up(table, parent_rate, rate, flags);
}
static bool _is_best_div(unsigned long rate, unsigned long now,
unsigned long best, unsigned long flags)
{
if (flags & CLK_DIVIDER_ROUND_CLOSEST)
return abs(rate - now) < abs(rate - best);
return now <= rate && now > best;
}
static int _next_div(const struct clk_div_table *table, int div,
unsigned long flags)
{
div++;
if (flags & CLK_DIVIDER_POWER_OF_TWO)
return __roundup_pow_of_two(div);
if (table)
return _round_up_table(table, div);
return div;
}
static int clk_divider_bestdiv(struct clk_hw *hw, struct clk_hw *parent,
unsigned long rate,
unsigned long *best_parent_rate,
const struct clk_div_table *table, u8 width,
unsigned long flags)
{
int i, bestdiv = 0;
unsigned long parent_rate, best = 0, now, maxdiv;
unsigned long parent_rate_saved = *best_parent_rate;
if (!rate)
rate = 1;
maxdiv = _get_maxdiv(table, width, flags);
if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
parent_rate = *best_parent_rate;
bestdiv = _div_round(table, parent_rate, rate, flags);
bestdiv = bestdiv == 0 ? 1 : bestdiv;
bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
return bestdiv;
}
/*
* The maximum divider we can use without overflowing
* unsigned long in rate * i below
*/
maxdiv = min(ULONG_MAX / rate, maxdiv);
for (i = _next_div(table, 0, flags); i <= maxdiv;
i = _next_div(table, i, flags)) {
if (rate * i == parent_rate_saved) {
/*
* 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.
*/
*best_parent_rate = parent_rate_saved;
return i;
}
parent_rate = clk_hw_round_rate(parent, rate * i);
now = DIV_ROUND_UP_ULL((u64)parent_rate, i);
if (_is_best_div(rate, now, best, flags)) {
bestdiv = i;
best = now;
*best_parent_rate = parent_rate;
}
}
if (!bestdiv) {
bestdiv = _get_maxdiv(table, width, flags);
*best_parent_rate = clk_hw_round_rate(parent, 1);
}
return bestdiv;
}
long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
unsigned long rate, unsigned long *prate,
const struct clk_div_table *table,
u8 width, unsigned long flags)
{
int div;
div = clk_divider_bestdiv(hw, parent, rate, prate, table, width, flags);
return DIV_ROUND_UP_ULL((u64)*prate, div);
}
EXPORT_SYMBOL_GPL(divider_round_rate_parent);
long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
unsigned long rate, unsigned long *prate,
const struct clk_div_table *table, u8 width,
unsigned long flags, unsigned int val)
{
int div;
div = _get_div(table, val, flags, width);
/* Even a read-only clock can propagate a rate change */
if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
if (!parent)
return -EINVAL;
*prate = clk_hw_round_rate(parent, rate * div);
}
return DIV_ROUND_UP_ULL((u64)*prate, div);
}
EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent);
static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_divider *divider = to_clk_divider(hw);
/* if read only, just return current value */
if (divider->flags & CLK_DIVIDER_READ_ONLY) {
u32 val;
val = clk_div_readl(divider) >> divider->shift;
val &= clk_div_mask(divider->width);
return divider_ro_round_rate(hw, rate, prate, divider->table,
divider->width, divider->flags,
val);
}
return divider_round_rate(hw, rate, prate, divider->table,
divider->width, divider->flags);
}
int divider_get_val(unsigned long rate, unsigned long parent_rate,
const struct clk_div_table *table, u8 width,
unsigned long flags)
{
unsigned int div, value;
div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
if (!_is_valid_div(table, div, flags))
return -EINVAL;
value = _get_val(table, div, flags, width);
return min_t(unsigned int, value, clk_div_mask(width));
}
EXPORT_SYMBOL_GPL(divider_get_val);
static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_divider *divider = to_clk_divider(hw);
int value;
unsigned long flags = 0;
u32 val;
value = divider_get_val(rate, parent_rate, divider->table,
divider->width, divider->flags);
if (value < 0)
return value;
if (divider->lock)
spin_lock_irqsave(divider->lock, flags);
else
__acquire(divider->lock);
if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
val = clk_div_mask(divider->width) << (divider->shift + 16);
} else {
val = clk_div_readl(divider);
val &= ~(clk_div_mask(divider->width) << divider->shift);
}
val |= (u32)value << divider->shift;
clk_div_writel(divider, val);
if (divider->lock)
spin_unlock_irqrestore(divider->lock, flags);
else
__release(divider->lock);
return 0;
}
const struct clk_ops clk_divider_ops = {
.recalc_rate = clk_divider_recalc_rate,
.round_rate = clk_divider_round_rate,
.set_rate = clk_divider_set_rate,
};
EXPORT_SYMBOL_GPL(clk_divider_ops);
const struct clk_ops clk_divider_ro_ops = {
.recalc_rate = clk_divider_recalc_rate,
.round_rate = clk_divider_round_rate,
};
EXPORT_SYMBOL_GPL(clk_divider_ro_ops);
struct clk_hw *__clk_hw_register_divider(struct device *dev,
struct device_node *np, const char *name,
const char *parent_name, const struct clk_hw *parent_hw,
const struct clk_parent_data *parent_data, unsigned long flags,
void __iomem *reg, u8 shift, u8 width, u8 clk_divider_flags,
const struct clk_div_table *table, spinlock_t *lock)
{
struct clk_divider *div;
struct clk_hw *hw;
struct clk_init_data init = {};
int ret;
if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
if (width + shift > 16) {
pr_warn("divider value exceeds LOWORD field\n");
return ERR_PTR(-EINVAL);
}
}
/* allocate the divider */
div = kzalloc(sizeof(*div), GFP_KERNEL);
if (!div)
return ERR_PTR(-ENOMEM);
init.name = name;
if (clk_divider_flags & CLK_DIVIDER_READ_ONLY)
init.ops = &clk_divider_ro_ops;
else
init.ops = &clk_divider_ops;
init.flags = flags;
init.parent_names = (parent_name ? &parent_name: NULL);
init.num_parents = (parent_name ? 1 : 0);
/* struct clk_divider assignments */
div->reg = reg;
div->shift = shift;
div->width = width;
div->flags = clk_divider_flags;
div->lock = lock;
div->hw.init = &init;
div->table = table;
/* register the clock */
hw = &div->hw;
ret = clk_hw_register(dev, hw);
if (ret) {
kfree(div);
hw = ERR_PTR(ret);
}
return hw;
}
EXPORT_SYMBOL_GPL(__clk_hw_register_divider);
/**
* clk_register_divider_table - register a table based divider clock with
* the clock framework
* @dev: device registering this clock
* @name: name of this clock
* @parent_name: name of clock's parent
* @flags: framework-specific flags
* @reg: register address to adjust divider
* @shift: number of bits to shift the bitfield
* @width: width of the bitfield
* @clk_divider_flags: divider-specific flags for this clock
* @table: array of divider/value pairs ending with a div set to 0
* @lock: shared register lock for this clock
*/
struct clk *clk_register_divider_table(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 shift, u8 width,
u8 clk_divider_flags, const struct clk_div_table *table,
spinlock_t *lock)
{
struct clk_hw *hw;
hw = __clk_hw_register_divider(dev, NULL, name, parent_name, NULL,
NULL, flags, reg, shift, width, clk_divider_flags,
table, lock);
if (IS_ERR(hw))
return ERR_CAST(hw);
return hw->clk;
}
EXPORT_SYMBOL_GPL(clk_register_divider_table);
void clk_unregister_divider(struct clk *clk)
{
struct clk_divider *div;
struct clk_hw *hw;
hw = __clk_get_hw(clk);
if (!hw)
return;
div = to_clk_divider(hw);
clk_unregister(clk);
kfree(div);
}
EXPORT_SYMBOL_GPL(clk_unregister_divider);
/**
* clk_hw_unregister_divider - unregister a clk divider
* @hw: hardware-specific clock data to unregister
*/
void clk_hw_unregister_divider(struct clk_hw *hw)
{
struct clk_divider *div;
div = to_clk_divider(hw);
clk_hw_unregister(hw);
kfree(div);
}
EXPORT_SYMBOL_GPL(clk_hw_unregister_divider);