[PATCH v13 10/11] clk: pwm: Use 64-bit division function

[Guru Das Srinagesh]

Since the PWM framework is switching struct pwm_args.period's datatype
to u64, prepare for this transition by using div64_u64 to handle a
64-bit divisor.

Also ensure that divide-by-zero (with fixed_rate as denominator) does
not happen with an explicit check with probe failure as a consequence.

To: David Laight <David.Laight@xxxxxxxxxx>
To: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
Cc: Stephen Boyd <sboyd@xxxxxxxxxx>
Cc: linux-clk@xxxxxxxxxxxxxxx

Signed-off-by: Guru Das Srinagesh <gurus@xxxxxxxxxxxxxx>
---
 drivers/clk/clk-pwm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-pwm.c b/drivers/clk/clk-pwm.c
index 87fe0b0e..86f2e2d 100644
--- a/drivers/clk/clk-pwm.c
+++ b/drivers/clk/clk-pwm.c
@@ -89,7 +89,12 @@ static int clk_pwm_probe(struct platform_device *pdev)
 	}
 
 	if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate))
-		clk_pwm->fixed_rate = NSEC_PER_SEC / pargs.period;
+		clk_pwm->fixed_rate = div64_u64(NSEC_PER_SEC, pargs.period);
+
+	if (!clk_pwm->fixed_rate) {
+		dev_err(&pdev->dev, "fixed_rate cannot be zero\n");
+		return -EINVAL;
+	}
 
 	if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
 	    pargs.period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project