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clk: at91: usb: fix at91rm9200 round and set rate

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at91rm9200_clk_usb_set_rate might fail depending on the requested rate,
because the parent_rate / rate remainder is not necessarily zero.
Moreover, when rounding down the calculated rate we might alter the
divisor calculation and end up with an invalid divisor.

To solve those problems, accept a non zero remainder, and always round
division to the closest result.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reported-by: Andreas Henriksson <andreas.henriksson@endian.se>
Tested-by: Andreas Henriksson <andreas.henriksson@endian.se>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
This commit is contained in:
Boris Brezillon 2014-11-14 19:54:49 +01:00 committed by Michael Turquette
parent 206c5f60a3
commit ff553ea1a3
1 changed files with 3 additions and 3 deletions
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6
drivers/clk/at91/clk-usb.c
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@ -253,7 +253,7 @@ static long at91rm9200_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate,
tmp_parent_rate = rate * usb->divisors[i];
tmp_parent_rate = __clk_round_rate(parent, tmp_parent_rate);
tmprate = tmp_parent_rate / usb->divisors[i];
tmprate = DIV_ROUND_CLOSEST(tmp_parent_rate, usb->divisors[i]);
if (tmprate < rate)
tmpdiff = rate - tmprate;
else
@ -281,10 +281,10 @@ static int at91rm9200_clk_usb_set_rate(struct clk_hw *hw, unsigned long rate,
struct at91_pmc *pmc = usb->pmc;
unsigned long div;
if (!rate || parent_rate % rate)
if (!rate)
return -EINVAL;
div = parent_rate / rate;
div = DIV_ROUND_CLOSEST(parent_rate, rate);
for (i = 0; i < RM9200_USB_DIV_TAB_SIZE; i++) {
if (usb->divisors[i] == div) {