clk: clk-divider: sync with kernel code
This updates the clk-divider to Kernel code, but without power-of-two divider support which we do not need yet. This also adds table based divider support to the divider. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
parent
503cc1518e
commit
d4aaca3647
|
@ -20,61 +20,192 @@
|
|||
#include <linux/clk.h>
|
||||
#include <linux/err.h>
|
||||
|
||||
static unsigned int clk_divider_maxdiv(struct clk_divider *div)
|
||||
#define div_mask(d) ((1 << ((d)->width)) - 1)
|
||||
|
||||
static unsigned int _get_maxdiv(struct clk_divider *divider)
|
||||
{
|
||||
if (div->flags & CLK_DIVIDER_ONE_BASED)
|
||||
return (1 << div->width) - 1;
|
||||
return 1 << div->width;
|
||||
if (divider->flags & CLK_DIVIDER_ONE_BASED)
|
||||
return div_mask(divider);
|
||||
return div_mask(divider) + 1;
|
||||
}
|
||||
|
||||
static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
|
||||
unsigned long parent_rate)
|
||||
static unsigned int _get_table_div(const struct clk_div_table *table,
|
||||
unsigned int val)
|
||||
{
|
||||
struct clk_divider *div = container_of(clk, struct clk_divider, clk);
|
||||
unsigned int val, divval;
|
||||
|
||||
if (rate > parent_rate)
|
||||
rate = parent_rate;
|
||||
if (!rate)
|
||||
rate = 1;
|
||||
|
||||
divval = DIV_ROUND_UP(parent_rate, rate);
|
||||
if (divval > clk_divider_maxdiv(div))
|
||||
divval = clk_divider_maxdiv(div);
|
||||
|
||||
if (!(div->flags & CLK_DIVIDER_ONE_BASED))
|
||||
divval--;
|
||||
|
||||
val = readl(div->reg);
|
||||
val &= ~(((1 << div->width) - 1) << div->shift);
|
||||
val |= divval << div->shift;
|
||||
writel(val, div->reg);
|
||||
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->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, unsigned int div)
|
||||
{
|
||||
if (divider->flags & CLK_DIVIDER_ONE_BASED)
|
||||
return div;
|
||||
if (divider->table)
|
||||
return _get_table_val(divider->table, div);
|
||||
return div - 1;
|
||||
}
|
||||
|
||||
static unsigned long clk_divider_recalc_rate(struct clk *clk,
|
||||
unsigned long parent_rate)
|
||||
{
|
||||
struct clk_divider *div = container_of(clk, struct clk_divider, clk);
|
||||
unsigned int val;
|
||||
struct clk_divider *divider = container_of(clk, struct clk_divider, clk);
|
||||
unsigned int div, val;
|
||||
|
||||
val = readl(div->reg) >> div->shift;
|
||||
val &= (1 << div->width) - 1;
|
||||
val = readl(divider->reg) >> divider->shift;
|
||||
val &= div_mask(divider);
|
||||
|
||||
if (div->flags & CLK_DIVIDER_ONE_BASED) {
|
||||
if (!val)
|
||||
val++;
|
||||
} else {
|
||||
val++;
|
||||
div = _get_div(divider, val);
|
||||
|
||||
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->table)
|
||||
return _is_valid_table_div(divider->table, div);
|
||||
return true;
|
||||
}
|
||||
|
||||
static int clk_divider_bestdiv(struct clk *clk, unsigned long rate,
|
||||
unsigned long *best_parent_rate)
|
||||
{
|
||||
struct clk_divider *divider = container_of(clk, struct clk_divider, clk);
|
||||
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->flags & 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;
|
||||
}
|
||||
|
||||
return parent_rate / val;
|
||||
/*
|
||||
* 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(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(clk), 1);
|
||||
}
|
||||
|
||||
return bestdiv;
|
||||
}
|
||||
|
||||
static long clk_divider_round_rate(struct clk *clk, unsigned long rate,
|
||||
unsigned long *parent_rate)
|
||||
{
|
||||
int div;
|
||||
|
||||
div = clk_divider_bestdiv(clk, rate, parent_rate);
|
||||
|
||||
return *parent_rate / div;
|
||||
}
|
||||
|
||||
static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
|
||||
unsigned long parent_rate)
|
||||
{
|
||||
struct clk_divider *divider = container_of(clk, struct clk_divider, clk);
|
||||
unsigned int div, value;
|
||||
u32 val;
|
||||
|
||||
if (clk->flags & CLK_SET_RATE_PARENT) {
|
||||
unsigned long best_parent_rate = parent_rate;
|
||||
div = clk_divider_bestdiv(clk, rate, &best_parent_rate);
|
||||
clk_set_rate(clk_get_parent(clk), best_parent_rate);
|
||||
} else {
|
||||
div = parent_rate / rate;
|
||||
}
|
||||
|
||||
value = _get_val(divider, div);
|
||||
|
||||
if (value > div_mask(divider))
|
||||
value = div_mask(divider);
|
||||
|
||||
val = readl(divider->reg);
|
||||
val &= ~(div_mask(divider) << divider->shift);
|
||||
val |= value << divider->shift;
|
||||
writel(val, divider->reg);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
struct clk_ops clk_divider_ops = {
|
||||
.set_rate = clk_divider_set_rate,
|
||||
.recalc_rate = clk_divider_recalc_rate,
|
||||
.round_rate = clk_divider_round_rate,
|
||||
};
|
||||
|
||||
struct clk *clk_divider(const char *name, const char *parent,
|
||||
|
|
|
@ -240,6 +240,9 @@ struct clk_divider {
|
|||
const char *parent;
|
||||
#define CLK_DIVIDER_ONE_BASED (1 << 0)
|
||||
unsigned flags;
|
||||
const struct clk_div_table *table;
|
||||
int max_div_index;
|
||||
int table_size;
|
||||
};
|
||||
|
||||
extern struct clk_ops clk_divider_ops;
|
||||
|
|
Loading…
Reference in New Issue