From: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
To: Vinicius Pedrosa <vinicius.eduardo.pedrosa@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Jiri Slaby <jirislaby@kernel.org>,
linux-serial <linux-serial@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org,
devicetree@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
linux-sunxi@lists.linux.dev, andre.przywara@arm.com,
wens@kernel.org, jernej.skrabec@gmail.com, samuel@sholland.org,
enzo.adriano.code@gmail.com
Subject: Re: [PATCH v2 2/4] serial: 8250_dw: Only accept a contiguous DLF readback
Date: Tue, 20 Oct 2026 16:02:29 +0300 (EEST) [thread overview]
Message-ID: <6c4a5613-7e10-64dc-a670-6407a4f1f6ed@linux.intel.com> (raw)
In-Reply-To: <20261020122746.41699-1-vinicius.eduardo.pedrosa@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 741 bytes --]
On Tue, 20 Oct 2026, Vinicius Pedrosa wrote:
> Hi Ilpo,
>
> On Tue, 20 Oct 2026, Ilpo Järvinen wrote:
>
> > For is_power_of_2(), 0 is not a power of two. And it also wouldn't make
> > sense to have zero bits in the bit field as it's same as no bit field so
> > using just is_power_of_2() should be enough.
>
> I think the reg != 0 check still needs to stay here, since the test is
> is_power_of_2(reg + 1), rather than is_power_of_2(reg).
>
> For reg == 0, reg + 1 is 1, and is_power_of_2(1) is true. So without
> the explicit reg check, a zero readback, meaning no DLF, would be
> accepted as a valid DLF.
>
> I'll keep it as:
>
> reg && is_power_of_2(reg + 1)
>
> in v3.
Ah, you're right.
--
i.
next prev parent reply other threads:[~2026-10-20 13:02 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-19 20:06 [PATCH v2 0/4] serial: 8250_dw: Allwinner A733 UART support Vinicius Pedrosa
2026-10-19 20:06 ` [PATCH v2 1/4] serial: 8250_dw: Keep the BUSY-safe divisor hook when DLF is present Vinicius Pedrosa
2026-10-19 20:26 ` sashiko-bot
2026-10-20 8:30 ` Andy Shevchenko
2026-10-20 8:51 ` Andy Shevchenko
2026-10-20 10:47 ` Vinicius Pedrosa
2026-10-19 20:06 ` [PATCH v2 2/4] serial: 8250_dw: Only accept a contiguous DLF readback Vinicius Pedrosa
2026-10-19 20:24 ` sashiko-bot
2026-10-20 6:11 ` Jiri Slaby
2026-10-20 8:31 ` Andy Shevchenko
2026-10-20 11:50 ` Ilpo Järvinen
2026-10-20 12:27 ` Vinicius Pedrosa
2026-10-20 13:02 ` Ilpo Järvinen [this message]
2026-10-20 10:47 ` Vinicius Pedrosa
2026-10-19 20:06 ` [PATCH v2 3/4] dt-bindings: serial: snps-dw-apb-uart: Add Allwinner A733 Vinicius Pedrosa
2026-10-19 20:24 ` sashiko-bot
2026-10-19 20:06 ` [PATCH v2 4/4] serial: 8250_dw: Add Allwinner A733 UART Vinicius Pedrosa
2026-10-19 20:24 ` sashiko-bot
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