From: Guenter Roeck <linux@roeck-us.net>
To: Lee Jones <lee.jones@linaro.org>
Cc: Damien Riegel <damien.riegel@savoirfairelinux.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-watchdog@vger.kernel.org, shawnguo@kernel.org,
kernel@pengutronix.de, wim@iguana.be, robh+dt@kernel.org,
sameo@linux.intel.com, dinh.linux@gmail.com,
kernel@savoirfairelinux.com
Subject: Re: [PATCH v3 2/5] mfd: syscon: add a DT property to set value width
Date: Wed, 18 Nov 2015 07:10:55 -0800 [thread overview]
Message-ID: <564C94FF.10004@roeck-us.net> (raw)
In-Reply-To: <20151118082144.GB3534@x1>
On 11/18/2015 12:21 AM, Lee Jones wrote:
[ ... ]
>>> Or, for more clarity:
>>>
>>> of_property_read_u32(np, "bus-width", &bus_width);
>>> if (bus_width)
>>>
>>> If you choose this version (which I think is my preferred method, don't
>>> forget to initialise 'bus_width' to zero.
>>>
>> Ignoring an error and depending on bus_width==0 to determine if the property
>> was provided seems odd, especially since it would "hide" if the bus-width
>> property is set to 0. In the original code, this would be detected as error.
>
> I'm not sure what you mean. If bus_width==0, then a problem has
> occurred and we will not use the value. If bus_width!=0 then we can
> assume that it's been set and (as the comment describes) the value
> will be checked for errors in regmap_init_mmio().
>
Your proposed code does not distinguish a missing property from "bus-width = <0>;".
It will silently ignore this case.
Guenter
next prev parent reply other threads:[~2015-11-18 15:11 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-16 19:06 [PATCH v3 0/5] Add board support for TS-4800 Damien Riegel
2015-11-16 19:06 ` [PATCH v3 1/5] of: add vendor prefix for Technologic Systems Damien Riegel
2015-11-16 19:06 ` [PATCH v3 2/5] mfd: syscon: add a DT property to set value width Damien Riegel
2015-11-17 9:19 ` Lee Jones
2015-11-17 9:21 ` Lee Jones
2015-11-17 17:26 ` Guenter Roeck
2015-11-18 8:21 ` Lee Jones
2015-11-18 15:10 ` Guenter Roeck [this message]
2015-11-18 15:27 ` Lee Jones
2015-11-20 23:13 ` Arnd Bergmann
2015-11-23 8:20 ` Lee Jones
2015-11-16 19:06 ` [PATCH v3 3/5] watchdog: ts4800: add driver for TS-4800 watchdog Damien Riegel
2015-11-17 17:56 ` Guenter Roeck
2015-11-16 19:06 ` [PATCH v3 4/5] ARM: imx_v6_v7_defconfig: add " Damien Riegel
2015-11-16 19:06 ` [PATCH v3 5/5] ARM: dts: TS-4800: add basic device tree Damien Riegel
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