From: "Giuseppe Lippolis" <giu.lippolis-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: <linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: spidev instantiated from DT
Date: Sun, 11 Dec 2016 13:03:18 +0100 [thread overview]
Message-ID: <002b01d253a6$9026e3b0$b074ab10$@gmail.com> (raw)
Dear All,
in the spidev.c driver there is a check preventing to export the SPI
subsystem to the userspace.
The commit message state:
spi: spidev: Warn loudly if instantiated from DT as "spidev"
Since spidev is a detail of how Linux controls a device rather than a
description of the hardware in the system we should never have a node
described as "spidev" in DT, any SPI device could be a spidev so this
is just not a useful description.
In order to help prevent users from writing such device trees generate a
warning if spidev is instantiated as a DT node without an ID in the
match
table.
Signed-off-by: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Currently in the spidec.c are registered two devices to use "legally" this
driver:
{ .compatible = "rohm,dh2228fv" },
{ .compatible = "lineartechnology,ltc2488" },
I cannot fully understand the rationale.
I have a board mounting an spi device. Currently no dedicated driver for
this devices exists.
So in my opinion, now, make sense to describe a device-tree with a "generic"
driver, allowing the userspace to control the device. When at the end a
dedicated driver will be available an update of the device tree will be
possible.
In alternative, make sense to add a dedicated .compatible = "xxx,yyy"
statements to attach the spidev driver to the specific device and allowing
the DT description as soon as a dedicated driver will be not available?
Can someone clarify me these points?
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next reply other threads:[~2016-12-11 12:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-11 12:03 Giuseppe Lippolis [this message]
2016-12-12 9:14 ` spidev instantiated from DT Geert Uytterhoeven
-- strict thread matches above, loose matches on Subject: below --
2016-12-12 19:45 Giuseppe Lippolis
2016-12-13 8:27 ` Geert Uytterhoeven
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