On 24 April 2015 at 14:06, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Friday 24 April 2015 13:48:57 Joachim Eastwood wrote: >> Hi, >> >> I am working on a DT supported SoC which has a 8250-based USART block >> with some additional features: >> - Two clocks (baud and reg) >> - DMA support (DMA engine) >> - RS485 >> >> Should support for these things be put into a 8250_<soc uart>.c file >> or should of_serial.c be extended? >> I am leaning towards creating a 8250_<soc uart>.c since the RS485 >> support can't be made generic here. > > Yes, that seems fine. If you need a separate file, don't put it > into of_serial.c > >> On a related note: How should quirks be handeled? >> Example: arch/arm/mach-lpc32xx/serial.c does applies a lot of errata >> workarounds. (This UART also requires two clocks) >> Should this be moved into a 8250_lpc32xx_uart.c file or it's there a >> better place to do this? > > That code probably needs to be rewritten before it can be put into > drivers/tty/serial/, but I think that's where it should go if anyone > finds the time, and can convert lpc32xx to use common-clk first. One other question: What is the preferred way of describing different UART SoC features in DT? 16550a is used as base on most NXP Cortex-M devices, but each UART can have different features like; IRDA, Smart card, RS485, sync mode (USART), DMA, hardware RTS/CTS pins and full modem pins. Features also differ between UARTs on the same device. I am thinking about either using different comp strings or some kind of feature flags in DT. (Freescale UART already uses feature flags like: "fsl,irda-mode" and "fsl,uart-has-rtscts") All UARTs on LPC1850 have RS485 and DMA support. In additional you have: UART0,2,3: sync mode and smart card. UART3: IRDA UART1: full modem control pin set. Comp strings could be something like: "nxp,lpc1850-usart" <- sync+smart card "nxp,lpc1850-usart-irda" <- sync+smart card+irda "nxp,lpc1850-uart-modem" <- modem-pins or feature flags like: nxp,sync-mode; nxp,rs485-mode; nxp,smart-card; nxp,irda-mode; nxp,full-modem; regards, Joachim Eastwood -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
