Commit b4761198 authored by Tero Kristo's avatar Tero Kristo Committed by Mike Turquette

CLK: ti: add support for ti divider-clock

This patch adds support for TI divider clock binding, which simply uses
the basic clock divider to provide the features needed.
Signed-off-by: default avatarTero Kristo <t-kristo@ti.com>
Acked-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarMike Turquette <mturquette@linaro.org>
parent 975e1548
Binding for TI divider clock
Binding status: Unstable - ABI compatibility may be broken in the future
This binding uses the common clock binding[1]. It assumes a
register-mapped adjustable clock rate divider that does not gate and has
only one input clock or parent. By default the value programmed into
the register is one less than the actual divisor value. E.g:
register value actual divisor value
0 1
1 2
2 3
This assumption may be modified by the following optional properties:
ti,index-starts-at-one - valid divisor values start at 1, not the default
of 0. E.g:
register value actual divisor value
1 1
2 2
3 3
ti,index-power-of-two - valid divisor values are powers of two. E.g:
register value actual divisor value
0 1
1 2
2 4
Additionally an array of valid dividers may be supplied like so:
ti,dividers = <4>, <8>, <0>, <16>;
Which will map the resulting values to a divisor table by their index:
register value actual divisor value
0 4
1 8
2 <invalid divisor, skipped>
3 16
Any zero value in this array means the corresponding bit-value is invalid
and must not be used.
The binding must also provide the register to control the divider and
unless the divider array is provided, min and max dividers. Optionally
the number of bits to shift that mask, if necessary. If the shift value
is missing it is the same as supplying a zero shift.
This binding can also optionally provide support to the hardware autoidle
feature, see [2].
[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
[2] Documentation/devicetree/bindings/clock/ti/autoidle.txt
Required properties:
- compatible : shall be "ti,divider-clock" or "ti,composite-divider-clock".
- #clock-cells : from common clock binding; shall be set to 0.
- clocks : link to phandle of parent clock
- reg : offset for register controlling adjustable divider
Optional properties:
- clock-output-names : from common clock binding.
- ti,dividers : array of integers defining divisors
- ti,bit-shift : number of bits to shift the divider value, defaults to 0
- ti,min-div : min divisor for dividing the input clock rate, only
needed if the first divisor is offset from the default value (1)
- ti,max-div : max divisor for dividing the input clock rate, only needed
if ti,dividers is not defined.
- ti,index-starts-at-one : valid divisor programming starts at 1, not zero,
only valid if ti,dividers is not defined.
- ti,index-power-of-two : valid divisor programming must be a power of two,
only valid if ti,dividers is not defined.
- ti,autoidle-shift : bit shift of the autoidle enable bit for the clock,
see [2]
- ti,invert-autoidle-bit : autoidle is enabled by setting the bit to 0,
see [2]
- ti,set-rate-parent : clk_set_rate is propagated to parent
Examples:
dpll_usb_m2_ck: dpll_usb_m2_ck@4a008190 {
#clock-cells = <0>;
compatible = "ti,divider-clock";
clocks = <&dpll_usb_ck>;
ti,max-div = <127>;
reg = <0x190>;
ti,index-starts-at-one;
};
aess_fclk: aess_fclk@4a004528 {
#clock-cells = <0>;
compatible = "ti,divider-clock";
clocks = <&abe_clk>;
ti,bit-shift = <24>;
reg = <0x528>;
ti,max-div = <2>;
};
dpll_core_m3x2_div_ck: dpll_core_m3x2_div_ck {
#clock-cells = <0>;
compatible = "ti,composite-divider-clock";
clocks = <&dpll_core_x2_ck>;
ti,max-div = <31>;
reg = <0x0134>;
ti,index-starts-at-one;
};
ssi_ssr_div_fck_3430es2: ssi_ssr_div_fck_3430es2 {
#clock-cells = <0>;
compatible = "ti,composite-divider-clock";
clocks = <&corex2_fck>;
ti,bit-shift = <8>;
reg = <0x0a40>;
ti,dividers = <0>, <1>, <2>, <3>, <4>, <0>, <6>, <0>, <8>;
};
ifneq ($(CONFIG_OF),)
obj-y += clk.o autoidle.o
clk-common = dpll.o composite.o
clk-common = dpll.o composite.o divider.o
endif
......@@ -31,7 +31,7 @@
static unsigned long ti_composite_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
return clk_divider_ops.recalc_rate(hw, parent_rate);
return ti_clk_divider_ops.recalc_rate(hw, parent_rate);
}
static long ti_composite_round_rate(struct clk_hw *hw, unsigned long rate,
......
/*
* TI Divider Clock
*
* Copyright (C) 2013 Texas Instruments, Inc.
*
* Tero Kristo <t-kristo@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/clk/ti.h>
#undef pr_fmt
#define pr_fmt(fmt) "%s: " fmt, __func__
#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
#define div_mask(d) ((1 << ((d)->width)) - 1)
static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
{
unsigned int maxdiv = 0;
const struct clk_div_table *clkt;
for (clkt = table; clkt->div; clkt++)
if (clkt->div > maxdiv)
maxdiv = clkt->div;
return maxdiv;
}
static unsigned int _get_maxdiv(struct clk_divider *divider)
{
if (divider->flags & CLK_DIVIDER_ONE_BASED)
return div_mask(divider);
if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
return 1 << div_mask(divider);
if (divider->table)
return _get_table_maxdiv(divider->table);
return div_mask(divider) + 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(struct clk_divider *divider, unsigned int val)
{
if (divider->flags & CLK_DIVIDER_ONE_BASED)
return val;
if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
return 1 << val;
if (divider->table)
return _get_table_div(divider->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(struct clk_divider *divider, u8 div)
{
if (divider->flags & CLK_DIVIDER_ONE_BASED)
return div;
if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
return __ffs(div);
if (divider->table)
return _get_table_val(divider->table, div);
return div - 1;
}
static unsigned long ti_clk_divider_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_divider *divider = to_clk_divider(hw);
unsigned int div, val;
val = ti_clk_ll_ops->clk_readl(divider->reg) >> divider->shift;
val &= div_mask(divider);
div = _get_div(divider, val);
if (!div) {
WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
"%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
__clk_get_name(hw->clk));
return parent_rate;
}
return parent_rate / div;
}
/*
* 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)
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(struct clk_divider *divider, unsigned int div)
{
if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
return is_power_of_2(div);
if (divider->table)
return _is_valid_table_div(divider->table, div);
return true;
}
static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
unsigned long *best_parent_rate)
{
struct clk_divider *divider = to_clk_divider(hw);
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(divider);
if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
parent_rate = *best_parent_rate;
bestdiv = DIV_ROUND_UP(parent_rate, rate);
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 = 1; i <= maxdiv; i++) {
if (!_is_valid_div(divider, i))
continue;
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_round_rate(__clk_get_parent(hw->clk),
MULT_ROUND_UP(rate, i));
now = parent_rate / i;
if (now <= rate && now > best) {
bestdiv = i;
best = now;
*best_parent_rate = parent_rate;
}
}
if (!bestdiv) {
bestdiv = _get_maxdiv(divider);
*best_parent_rate =
__clk_round_rate(__clk_get_parent(hw->clk), 1);
}
return bestdiv;
}
static long ti_clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
int div;
div = ti_clk_divider_bestdiv(hw, rate, prate);
return *prate / div;
}
static int ti_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_divider *divider = to_clk_divider(hw);
unsigned int div, value;
unsigned long flags = 0;
u32 val;
div = parent_rate / rate;
value = _get_val(divider, div);
if (value > div_mask(divider))
value = div_mask(divider);
if (divider->lock)
spin_lock_irqsave(divider->lock, flags);
if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
val = div_mask(divider) << (divider->shift + 16);
} else {
val = ti_clk_ll_ops->clk_readl(divider->reg);
val &= ~(div_mask(divider) << divider->shift);
}
val |= value << divider->shift;
ti_clk_ll_ops->clk_writel(val, divider->reg);
if (divider->lock)
spin_unlock_irqrestore(divider->lock, flags);
return 0;
}
const struct clk_ops ti_clk_divider_ops = {
.recalc_rate = ti_clk_divider_recalc_rate,
.round_rate = ti_clk_divider_round_rate,
.set_rate = ti_clk_divider_set_rate,
};
static struct clk *_register_divider(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_divider *div;
struct clk *clk;
struct clk_init_data init;
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) {
pr_err("%s: could not allocate divider clk\n", __func__);
return ERR_PTR(-ENOMEM);
}
init.name = name;
init.ops = &ti_clk_divider_ops;
init.flags = flags | CLK_IS_BASIC;
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 */
clk = clk_register(dev, &div->hw);
if (IS_ERR(clk))
kfree(div);
return clk;
}
static struct clk_div_table
__init *ti_clk_get_div_table(struct device_node *node)
{
struct clk_div_table *table;
const __be32 *divspec;
u32 val;
u32 num_div;
u32 valid_div;
int i;
divspec = of_get_property(node, "ti,dividers", &num_div);
if (!divspec)
return NULL;
num_div /= 4;
valid_div = 0;
/* Determine required size for divider table */
for (i = 0; i < num_div; i++) {
of_property_read_u32_index(node, "ti,dividers", i, &val);
if (val)
valid_div++;
}
if (!valid_div) {
pr_err("no valid dividers for %s table\n", node->name);
return ERR_PTR(-EINVAL);
}
table = kzalloc(sizeof(*table) * (valid_div + 1), GFP_KERNEL);
if (!table)
return ERR_PTR(-ENOMEM);
valid_div = 0;
for (i = 0; i < num_div; i++) {
of_property_read_u32_index(node, "ti,dividers", i, &val);
if (val) {
table[valid_div].div = val;
table[valid_div].val = i;
valid_div++;
}
}
return table;
}
static int _get_divider_width(struct device_node *node,
const struct clk_div_table *table,
u8 flags)
{
u32 min_div;
u32 max_div;
u32 val = 0;
u32 div;
if (!table) {
/* Clk divider table not provided, determine min/max divs */
if (of_property_read_u32(node, "ti,min-div", &min_div))
min_div = 1;
if (of_property_read_u32(node, "ti,max-div", &max_div)) {
pr_err("no max-div for %s!\n", node->name);
return -EINVAL;
}
/* Determine bit width for the field */
if (flags & CLK_DIVIDER_ONE_BASED)
val = 1;
div = min_div;
while (div < max_div) {
if (flags & CLK_DIVIDER_POWER_OF_TWO)
div <<= 1;
else
div++;
val++;
}
} else {
div = 0;
while (table[div].div) {
val = table[div].val;
div++;
}
}
return fls(val);
}
static int __init ti_clk_divider_populate(struct device_node *node,
void __iomem **reg, const struct clk_div_table **table,
u32 *flags, u8 *div_flags, u8 *width, u8 *shift)
{
u32 val;
*reg = ti_clk_get_reg_addr(node, 0);
if (!*reg)
return -EINVAL;
if (!of_property_read_u32(node, "ti,bit-shift", &val))
*shift = val;
else
*shift = 0;
*flags = 0;
*div_flags = 0;
if (of_property_read_bool(node, "ti,index-starts-at-one"))
*div_flags |= CLK_DIVIDER_ONE_BASED;
if (of_property_read_bool(node, "ti,index-power-of-two"))
*div_flags |= CLK_DIVIDER_POWER_OF_TWO;
if (of_property_read_bool(node, "ti,set-rate-parent"))
*flags |= CLK_SET_RATE_PARENT;
*table = ti_clk_get_div_table(node);
if (IS_ERR(*table))
return PTR_ERR(*table);
*width = _get_divider_width(node, *table, *div_flags);
return 0;
}
/**
* of_ti_divider_clk_setup - Setup function for simple div rate clock
* @node: device node for this clock
*
* Sets up a basic divider clock.
*/
static void __init of_ti_divider_clk_setup(struct device_node *node)
{
struct clk *clk;
const char *parent_name;
void __iomem *reg;
u8 clk_divider_flags = 0;
u8 width = 0;
u8 shift = 0;
const struct clk_div_table *table = NULL;
u32 flags = 0;
parent_name = of_clk_get_parent_name(node, 0);
if (ti_clk_divider_populate(node, &reg, &table, &flags,
&clk_divider_flags, &width, &shift))
goto cleanup;
clk = _register_divider(NULL, node->name, parent_name, flags, reg,
shift, width, clk_divider_flags, table, NULL);
if (!IS_ERR(clk)) {
of_clk_add_provider(node, of_clk_src_simple_get, clk);
of_ti_clk_autoidle_setup(node);
return;
}
cleanup:
kfree(table);
}
CLK_OF_DECLARE(divider_clk, "ti,divider-clock", of_ti_divider_clk_setup);
static void __init of_ti_composite_divider_clk_setup(struct device_node *node)
{
struct clk_divider *div;
u32 val;
div = kzalloc(sizeof(*div), GFP_KERNEL);
if (!div)
return;
if (ti_clk_divider_populate(node, &div->reg, &div->table, &val,
&div->flags, &div->width, &div->shift) < 0)
goto cleanup;
if (!ti_clk_add_component(node, &div->hw, CLK_COMPONENT_TYPE_DIVIDER))
return;
cleanup:
kfree(div->table);
kfree(div);
}
CLK_OF_DECLARE(ti_composite_divider_clk, "ti,composite-divider-clock",
of_ti_composite_divider_clk_setup);
......@@ -223,6 +223,8 @@ struct ti_clk_ll_ops {
extern struct ti_clk_ll_ops *ti_clk_ll_ops;
extern const struct clk_ops ti_clk_divider_ops;
#define to_clk_hw_omap(_hw) container_of(_hw, struct clk_hw_omap, hw)
void omap2_init_clk_hw_omap_clocks(struct clk *clk);
......
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