From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: jdelvare@suse.com, corbet@lwn.net, afd@ti.com,
linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org
Subject: Re: [PATCH 2/2] hwmon: ina3221: Add enable sysfs nodes
Date: Wed, 26 Sep 2018 11:02:44 -0700 [thread overview]
Message-ID: <20180926180243.GA6329@Asurada-Nvidia.nvidia.com> (raw)
In-Reply-To: <0cfe55e1-10d8-ac1f-8b6e-73777074a219@roeck-us.net>
On Wed, Sep 26, 2018 at 06:06:32AM -0700, Guenter Roeck wrote:
> On 09/25/2018 11:42 PM, Nicolin Chen wrote:
> > The inX_enable interface allows user space to enable or disable
> > the corresponding channel. Meanwhile, according to hwmon ABI, a
> > disabled channel/sensor should return -ENODATA as a read result.
> >
> > However, there're configurable nodes sharing the same __show()
> > functions. So this change also adds to check if the attribute is
> > read-only to make sure it's not reading a configuration but the
> > sensor data.
> One necessary high level change I don't see below: With this change,
> we should no longer drop a channel entirely if it is disabled from
> devicetree. All channels should be visible but report -ENODATA if
> disabled. In other words, it should be possible for the 'enable' flag
> to override settings in DT.
Hmm...I don't feel so convinced here. The status in DT binding isn't
exactly a setting but a physical status: if a hardware design leaves
a channel to be disconnected, I don't really see a point in enabling
it in the runtime. Or maybe you can shed some light on it?
Meanwhile, I believe the enable nodes are necessary in either way as
users could decide to disable the connected channels, based on their
use cases, to save power.
Thanks
Nicolin
next prev parent reply other threads:[~2018-09-26 18:02 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 6:42 [PATCH 0/2] hwmon: ina3221: Add power and enable sysfs nodes Nicolin Chen
2018-09-26 6:42 ` [PATCH 1/2] hwmon: ina3221: Add power " Nicolin Chen
2018-09-26 12:34 ` Guenter Roeck
2018-09-26 18:20 ` Nicolin Chen
2018-09-26 19:45 ` Guenter Roeck
2018-09-26 19:49 ` Nicolin Chen
2018-09-26 6:42 ` [PATCH 2/2] hwmon: ina3221: Add enable " Nicolin Chen
2018-09-26 13:06 ` Guenter Roeck
2018-09-26 18:02 ` Nicolin Chen [this message]
2018-09-26 19:58 ` Guenter Roeck
2018-09-26 20:25 ` Nicolin Chen
2018-09-26 20:44 ` Guenter Roeck
2018-09-26 21:55 ` Nicolin Chen
2018-09-27 16:05 ` Guenter Roeck
2018-09-27 18:39 ` Nicolin Chen
2018-09-27 22:26 ` Nicolin Chen
2018-09-27 22:52 ` Guenter Roeck
2018-09-27 23:14 ` Nicolin Chen
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