From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: David Laight <david.laight.linux@gmail.com>
Cc: linux-iio@vger.kernel.org, chrome-platform@lists.linux.dev,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
"Jonathan Cameron" <jic23@kernel.org>,
"David Lechner" <dlechner@baylibre.com>,
"Nuno Sá" <nuno.sa@analog.com>,
"Andy Shevchenko" <andy@kernel.org>,
"Benson Leung" <bleung@chromium.org>,
"Guenter Roeck" <groeck@chromium.org>,
"Lars-Peter Clausen" <lars@metafoo.de>,
"Michael Hennerich" <Michael.Hennerich@analog.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
"Daniel W. S. Almeida" <dwlsalmeida@gmail.com>
Subject: Re: [PATCH v1 2/6] units: Add value of π * 10⁹
Date: Tue, 28 Oct 2025 10:08:04 +0200 [thread overview]
Message-ID: <aQB55GjWQL3VD1MO@smile.fi.intel.com> (raw)
In-Reply-To: <20251027193033.69728215@pumpkin>
On Mon, Oct 27, 2025 at 07:30:33PM +0000, David Laight wrote:
> On Mon, 27 Oct 2025 15:34:51 +0100
> Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
>
> > There are a few drivers that want to have this value, and at least one
> > known to come soon. Let's define a value for them.
> > +/* Value of π * 10⁹ */
> > +#define PI 3141592653LL
>
> Is that the right value?
> IIRC the next digits are 58979 (I used to know the next few as well)
> which means it should be rounded up.
Right, today I have the same thought that actually ChromeOS driver has a
off-by-one issue there.
Btw, do you know if we can have compile-time divisions that can make 32-bit
constants out of the 64-bit input? DIV_ROUND_CLOSEST_ULL() doesn't seem allow
that.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2025-10-28 8:08 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-27 14:34 [PATCH v1 0/6] iio: Introduce and use value of π Andy Shevchenko
2025-10-27 14:34 ` [PATCH v1 1/6] media: vidtv: Rename PI definition to PI_SAMPLES Andy Shevchenko
2025-10-30 7:24 ` Hans Verkuil
2025-10-27 14:34 ` [PATCH v1 2/6] units: Add value of π * 10⁹ Andy Shevchenko
2025-10-27 14:52 ` Jonathan Cameron
2025-10-27 14:59 ` David Lechner
2025-10-28 8:09 ` Andy Shevchenko
2025-10-27 19:30 ` David Laight
2025-10-28 8:08 ` Andy Shevchenko [this message]
2025-10-28 9:27 ` David Laight
2025-10-27 14:34 ` [PATCH v1 3/6] media: dvb-frontends: atbm8830: Convert to use PI definition Andy Shevchenko
2025-10-30 7:26 ` Hans Verkuil
2025-10-27 14:34 ` [PATCH v1 4/6] iio: cros_ec_sensors: " Andy Shevchenko
2025-10-27 14:34 ` [PATCH v1 5/6] iio: frequency: ad9523: " Andy Shevchenko
2025-10-27 14:34 ` [PATCH v1 6/6] iio: position: iqs624-pos: " Andy Shevchenko
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