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SubjectRE: [PATCH v8 01/12] clk: pwm: Use 64-bit division function
Date
From: Guru Das Srinagesh
> Sent: 11 March 2020 01:41
>
> 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.
>
> Cc: Michael Turquette <mturquette@baylibre.com>
> Cc: Stephen Boyd <sboyd@kernel.org>
> Cc: linux-clk@vger.kernel.org
>
> Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
> ---
> drivers/clk/clk-pwm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk-pwm.c b/drivers/clk/clk-pwm.c
> index 87fe0b0e..7b1f7a0 100644
> --- a/drivers/clk/clk-pwm.c
> +++ b/drivers/clk/clk-pwm.c
> @@ -89,7 +89,7 @@ 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);

That cannot be needed, a 32 bit division is fine.
More interesting would be whether pargs.period is sane (eg not zero).
I'd assign pargs.period to an 'unsigned int' variable
prior to the division (I hate casts - been bitten by them in the past.).

>
> 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

David

-
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