From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Giuseppe Lippolis" Subject: spidev instantiated from DT Date: Sun, 11 Dec 2016 13:03:18 +0100 Message-ID: <002b01d253a6$9026e3b0$b074ab10$@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Return-path: Content-Language: de Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: 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 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? -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html