redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

clk: iproc: Fix error in the pll post divider rate calculation 

The pll post divider code was using DIV_ROUND_UP when determining the
divider value best suited to produce the target frequency.
Using DIV_ROUND_CLOSEST will give us better divider values when
the division results in a small remainder.
Also, change the post divider clock over to the determine_rate api
instead of round_rate.

Signed-off-by: Simran Rai <ssimran@broadcom.com>
Signed-off-by: Lori Hikichi <lori.hikichi@broadcom.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
hifive-unleashed-5.1
Lori Hikichi 2017-08-14 12:00:39 -07:00 committed by Stephen Boyd
parent becf123772
commit 85151a6b0b
1 changed files with 17 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/clk/bcm/clk-iproc-pll.c
View File

@ -602,25 +602,26 @@ static unsigned long iproc_clk_recalc_rate(struct clk_hw *hw,
return clk->rate;
}
static long iproc_clk_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
static int iproc_clk_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
unsigned int div;
unsigned int bestdiv;
if (rate == 0 || *parent_rate == 0)
if (req->rate == 0)
return -EINVAL;
if (req->rate == req->best_parent_rate)
return 0;
if (rate == *parent_rate)
return *parent_rate;
bestdiv = DIV_ROUND_CLOSEST(req->best_parent_rate, req->rate);
if (bestdiv < 2)
req->rate = req->best_parent_rate;
div = DIV_ROUND_UP(*parent_rate, rate);
if (div < 2)
return *parent_rate;
if (bestdiv > 256)
bestdiv = 256;
if (div > 256)
div = 256;
req->rate = req->best_parent_rate / bestdiv;
return *parent_rate / div;
return 0;
}
static int iproc_clk_set_rate(struct clk_hw *hw, unsigned long rate,
@ -635,10 +636,10 @@ static int iproc_clk_set_rate(struct clk_hw *hw, unsigned long rate,
if (rate == 0 || parent_rate == 0)
return -EINVAL;
div = DIV_ROUND_CLOSEST(parent_rate, rate);
if (ctrl->flags & IPROC_CLK_MCLK_DIV_BY_2)
div = DIV_ROUND_UP(parent_rate, rate * 2);
else
div = DIV_ROUND_UP(parent_rate, rate);
div /= 2;
if (div > 256)
return -EINVAL;
@ -662,7 +663,7 @@ static const struct clk_ops iproc_clk_ops = {
.enable = iproc_clk_enable,
.disable = iproc_clk_disable,
.recalc_rate = iproc_clk_recalc_rate,
.round_rate = iproc_clk_round_rate,
.determine_rate = iproc_clk_determine_rate,
.set_rate = iproc_clk_set_rate,
};