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clk: at91: clk-generated: create function to find best_diff

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The way to find the best_diff and do the appropriate process afterwards
can be re-used.

This patch prepares the driver for an upcoming patch that will allow
clk_generated to determine the rate of the audio_pll.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
This commit is contained in:
Quentin Schulz 2017-08-10 08:34:04 +02:00 committed by Stephen Boyd
parent 0865805d82
commit 8a8f4bf0c4
1 changed files with 26 additions and 13 deletions
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39
drivers/clk/at91/clk-generated.c
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@ -99,15 +99,36 @@ clk_generated_recalc_rate(struct clk_hw *hw,
return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
}
static void clk_generated_best_diff(struct clk_rate_request *req,
struct clk_hw *parent,
unsigned long parent_rate, u32 div,
int *best_diff, long *best_rate)
{
unsigned long tmp_rate;
int tmp_diff;
if (!div)
tmp_rate = parent_rate;
else
tmp_rate = parent_rate / div;
tmp_diff = abs(req->rate - tmp_rate);
if (*best_diff < 0 || *best_diff > tmp_diff) {
*best_rate = tmp_rate;
*best_diff = tmp_diff;
req->best_parent_rate = parent_rate;
req->best_parent_hw = parent;
}
}
static int clk_generated_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct clk_generated *gck = to_clk_generated(hw);
struct clk_hw *parent = NULL;
long best_rate = -EINVAL;
unsigned long tmp_rate, min_rate;
unsigned long min_rate;
int best_diff = -1;
int tmp_diff;
int i;
for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
@ -125,18 +146,10 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
continue;
div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
if (!div)
tmp_rate = parent_rate;
else
tmp_rate = parent_rate / div;
tmp_diff = abs(req->rate - tmp_rate);
if (best_diff < 0 || best_diff > tmp_diff) {
best_rate = tmp_rate;
best_diff = tmp_diff;
req->best_parent_rate = parent_rate;
req->best_parent_hw = parent;
}
clk_generated_best_diff(req, parent, parent_rate, div,
&best_diff, &best_rate);
if (!best_diff)
break;