[PATCH 1/2] clk: at91: usb: fix at91rm9200 round and set rate

[Boris Brezillon]

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 at free-electrons.com>
Reported-by: Andreas Henriksson <andreas.henriksson at endian.se>
---
 drivers/clk/at91/clk-usb.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c
index 24b5b02..5b3b63c 100644
--- a/drivers/clk/at91/clk-usb.c
+++ b/drivers/clk/at91/clk-usb.c
@@ -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) {
-- 
1.9.1