Neil Brown send series which implement what was suggested in previous posts: https://lkml.org/lkml/2014/12/11/454 On Wed, Dec 10, 2014 at 11:50 PM, sre@xxxxxxxxxx <sre@xxxxxxxxxx> wrote: > Hi, > > On Wed, Dec 10, 2014 at 09:56:22PM +0100, Pavel Machek wrote: >> On Wed 2014-12-10 18:42:03, Mark Rutland wrote: >> > On Wed, Dec 10, 2014 at 05:02:42PM +0000, Arnd Bergmann wrote: >> > > On Wednesday 10 December 2014 17:43:33 Pavel Machek wrote: >> > > > >> > > > So, there's bluetooth chip that's connected to the SoC by UART and some >> > > > GPIOs. What would be right representation in the device tree? >> > > > Something like this? >> > > > >> > > > bluetooth { >> > > > compatible = "broadcom,bcm2048"; >> > > > uart = <&uart2>; >> > > > reset-gpios = <&gpio3 27 GPIO_ACTIVE_HIGH>; /* want 91 */ >> > > > host-wakeup-gpios = <&gpio4 5 GPIO_ACTIVE_HIGH>; /* want 101 */ >> > > > bluetooth-wakeup-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>; /* want 37 */ >> > > > chip-type = >; >> > > > bt-sysclk = <2>; >> > > > reset-gpio-shared = <0>; >> > > > }; >> > > > >> > > > Is there some way to prevent OMAP tty driver from binding to the >> > > > device and exporting the device to userspace? >> > > >> > > I think from the driver perspective, you want this to be a tty line >> > > discipline rather than a driver that attaches to the physical >> > > uart. >> > > >> > > For the DT representation, I fear we haven't got a precedent. A uart >> > > phandle sounds reasonable, but there might be other ways to do it >> > > and we should consider if there are better alternatives. It could >> > > possibly be a child node of the uart, but that would require other >> > > infrastructure in the kernel because we don't currently create >> > > devices for those. >> > >> > I think the child node is the way to go; that would match what we do for >> > I2C and SPI. We might need new infrastructure, but I don't think we >> > should treat this differently simlpy because we don't have that yet. >> >> Well, uart in this case looks more like a GPIO than an I2C (no >> addressing, just few wires). And we do phandle for GPIOs. > > Right and the devices use I2C for full communication and GPIOs as > helpers. I guess UART counts as full communication and not as helper. > > phandle vs child node is not a matter of adressing and btw where is > the difference between "5th gpio on 1st gpio controller" and "5th > address on 1st i2c controller"? > >> Actually, the chip also has PCM, analog audio, and "pc compatible?" >> connections, plus some connection to WIFI. So we may need more >> phandles there.... > > This is much harder to solve. I think we don't have a DT binding for > a device, which uses two communication interfaces as the bcm2048 > (uart & i2c). OTOH we may just add a slave device for the fm-radio > part like this: > > uart { > bcm2048 { > stuff; > }; > }; > > i2c { > bcm2048-radio { > master = <&bcm2048>; > }; > }; > > -- Sebastian > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > BR, marek -- as simple and primitive as possible ------------------------------------------------- Marek Belisko - OPEN-NANDRA Freelance Developer Ruska Nova Ves 219 | Presov, 08005 Slovak Republic Tel: +421 915 052 184 skype: marekwhite twitter: #opennandra web: http://open-nandra.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
