From: Guru Das Srinagesh <gurus@codeaurora.org>
To: linux-pwm@vger.kernel.org
Cc: "Thierry Reding" <thierry.reding@gmail.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Subbaraman Narayanamurthy" <subbaram@codeaurora.org>,
"David Collins" <collinsd@codeaurora.org>,
linux-kernel@vger.kernel.org,
"Michael Turquette" <mturquette@baylibre.com>,
"Stephen Boyd" <sboyd@kernel.org>,
linux-clk@vger.kernel.org,
"David Laight" <David.Laight@ACULAB.COM>,
"Arnd Bergmann" <arnd@arndb.de>
Subject: Re: [PATCH v12 10/11] clk: pwm: Use 64-bit division function
Date: Fri, 10 Apr 2020 12:15:03 -0700 [thread overview]
Message-ID: <20200410191503.GA21571@codeaurora.org> (raw)
In-Reply-To: <d5127aa19a128edf7c3dd437291b366b77be4ac5.1586414867.git.gurus@codeaurora.org>
+ Arnd, David
On Wed, Apr 08, 2020 at 11:52:39PM -0700, Guru Das Srinagesh wrote:
> 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@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 | 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)) {
> --
Hello Arnd, David:
Sorry, missed cc-ing you both to this patch while sending it out. Could
you please review it when you get a chance to?
Thank you.
Guru Das.
next prev parent reply other threads:[~2020-04-10 19:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-09 6:52 [PATCH v12 00/11] Convert PWM period and duty cycle to u64 Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 01/11] drm/i915: Use 64-bit division macro Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 02/11] hwmon: pwm-fan: " Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 03/11] ir-rx51: " Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 04/11] pwm: clps711x: Cast period to u32 before use as divisor Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 05/11] pwm: pwm-imx-tpm: Use 64-bit division macro Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 06/11] pwm: imx27: Use 64-bit division macro and function Guru Das Srinagesh
2020-04-10 19:16 ` Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 07/11] pwm: sifive: Use 64-bit division macro Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 08/11] pwm: sun4i: Use nsecs_to_jiffies to avoid a division Guru Das Srinagesh
2020-04-10 19:20 ` Guru Das Srinagesh
2020-04-11 5:49 ` Chen-Yu Tsai
2020-04-09 6:52 ` [PATCH v12 09/11] backlight: pwm_bl: Use 64-bit division function Guru Das Srinagesh
2020-04-16 9:44 ` Lee Jones
2020-04-16 17:55 ` Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 10/11] clk: pwm: " Guru Das Srinagesh
2020-04-10 19:15 ` Guru Das Srinagesh [this message]
2020-04-09 6:52 ` [PATCH v12 11/11] pwm: core: Convert period and duty cycle to u64 Guru Das Srinagesh
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