On 22 August 2016 at 23:23, H. Nikolaus Schaller <h...@goldelico.com> wrote: > Hi Sebastian, > >> Am 22.08.2016 um 22:39 schrieb Sebastian Reichel <s...@kernel.org>: >> >> Hi, >> >> On Sun, Aug 21, 2016 at 09:50:57AM +0200, H. Nikolaus Schaller wrote: >>>> Am 20.08.2016 um 15:34 schrieb One Thousand Gnomes >>>> <gno...@lxorguk.ukuu.org.uk>: >>>>> What it is not about are UART/RS232 converters connected through USB or >>>>> virtual >>>>> serial ports created for WWAN modems (e.g. /dev/ttyACM, /dev/ttyHSO). Or >>>>> BT devices >>>>> connected through USB (even if they also run HCI protocol). >>>> >>>> It actually has to be about both because you will find the exact same >>>> device wired via USB SSIC/HSIC to a USB UART or via a classic UART. Not is >>>> it just about embedded boards. >>> >>> Not necessarily. >>> >>> We often have two interface options for exactly the sam sensor chips. They >>> can be connected >>> either through SPI or I2C. Which means that there is a core driver for the >>> chip and two different >>> transport glue components (see e.g. iio/accel/bmc150). >>> >>> This does not require I2C to be able to handle SPI or vice versa or provide >>> a common API. >> >> I don't understand this comparison. I2C and SPI are different >> protocols, > > Yes, they are different on protocol level, but on both you transfer blocks of > data from/to a slave device > which usually can be addressed. And for some chips they are just two slightly > alternative serial interfaces. > >> while native UART and USB-connected UART are both UART. > > I see what you mean, but kernel divides between directly connected UART and > USB-connected UART. > > drivers/usb/serial/ vs. drivers/tty/serial/ > > to implement two different groups of UARTs. Although on user space level they > are harmonized again. > This is why I compare with i2c and spi. But each such comparison is not > perfect. > > Anyways, to me it looks as if everybody wants to make the solution work for > usb-uarts as well > (although I still would like to see a real world use-case).
I use a NFC reader attached to a PL2303 UART. It's a proof of concept solution but if I needed a finished product all it takes is to put the two pieces of PCB into a box with the USB connector sticking out. Or glue the PCB on the inside of a plastic part of a PC case. Thanks Michal
