From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: thierry.reding@gmail.com, linux-pwm@vger.kernel.org,
linux-amlogic@lists.infradead.org, narmstrong@baylibre.com,
jbrunet@baylibre.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, bichao.zheng@amlogic.com
Subject: Re: [PATCH 1/2] pwm: meson: consider 128 a valid pre-divider
Date: Mon, 1 Apr 2019 20:38:47 +0200 [thread overview]
Message-ID: <20190401183847.7xhlgff63cvlzz2h@pengutronix.de> (raw)
In-Reply-To: <20190401181817.11999-2-martin.blumenstingl@googlemail.com>
Hello Martin,
On Mon, Apr 01, 2019 at 08:18:16PM +0200, Martin Blumenstingl wrote:
> diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
> index f6e738ad7bd9..4b708c1fcb1d 100644
> --- a/drivers/pwm/pwm-meson.c
> +++ b/drivers/pwm/pwm-meson.c
> @@ -188,7 +188,7 @@ static int meson_pwm_calc(struct meson_pwm *meson,
> do_div(fin_ps, fin_freq);
>
> /* Calc pre_div with the period */
> - for (pre_div = 0; pre_div < MISC_CLK_DIV_MASK; pre_div++) {
> + for (pre_div = 0; pre_div <= MISC_CLK_DIV_MASK; pre_div++) {
> cnt = DIV_ROUND_CLOSEST_ULL((u64)period * 1000,
> fin_ps * (pre_div + 1));
> dev_dbg(meson->chip.dev, "fin_ps=%llu pre_div=%u cnt=%u\n",
You could even calculate pre_div without the loop.
Something like:
u64 pre_div = (u64)period * rate;
do_div_round_up(pre_div, NSEC_PER_SEC * 0xffff);
pre_div--;
(I didn't check rounding and maybe its off by one and ...) This would
also get rid of the strange 1000 that is currently used in the
calculation without a real benefit (unless I missed something).
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2019-04-01 18:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-01 18:18 [PATCH 0/2] pwm: meson: two small bug-fixes Martin Blumenstingl
2019-04-01 18:18 ` [PATCH 1/2] pwm: meson: consider 128 a valid pre-divider Martin Blumenstingl
2019-04-01 18:38 ` Uwe Kleine-König [this message]
2019-04-02 19:22 ` Martin Blumenstingl
2019-04-02 19:55 ` Uwe Kleine-König
2019-04-03 11:19 ` Neil Armstrong
2019-04-01 18:18 ` [PATCH 2/2] pwm: meson: don't disable pwm when setting duty repeatedly Martin Blumenstingl
2019-04-03 11:19 ` Neil Armstrong
2019-05-09 14:52 ` [PATCH 0/2] pwm: meson: two small bug-fixes Thierry Reding
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190401183847.7xhlgff63cvlzz2h@pengutronix.de \
--to=u.kleine-koenig@pengutronix.de \
--cc=bichao.zheng@amlogic.com \
--cc=jbrunet@baylibre.com \
--cc=linux-amlogic@lists.infradead.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pwm@vger.kernel.org \
--cc=martin.blumenstingl@googlemail.com \
--cc=narmstrong@baylibre.com \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).