[PATCH v12 10/11] clk: pwm: Use 64-bit division function

From: Guru Das Srinagesh
Date: Thu Apr 09 2020 - 02:53:16 EST


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.

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)) {
--
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