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    SubjectRe: [PATCH] serial/efm32: add new driver
    Hello,

    On Fri, Dec 23, 2011 at 09:44:28PM +0100, Uwe Kleine-König wrote:
    > On Fri, Dec 23, 2011 at 10:35:22AM +0000, Arnd Bergmann wrote:
    > > On Thursday 22 December 2011, Uwe Kleine-König wrote:
    > >
    > > > @@ -0,0 +1,14 @@
    > > > +* Energymicro efm32 UART
    > > > +
    > > > +Required properties:
    > > > +- compatible : Should be "efm32,usart"
    > > > +- reg : Address and length of the register set
    > > > +- interrupts : Should contain uart interrupt
    > > > +
    > > > +Example:
    > > > +
    > > > +uart@0x4000c400 {
    > > > + compatible = "efm32,usart";
    > > > + reg = <0x4000c400 0x400>;
    > > > + interrupts = <15>;
    > > > +};
    > >
    > > Do you know if the usart was actually designed by energymicro or licensed
    > > from another party? If it is a licensed part, it would be better to
    > > list the "compatible" value under the company name that made it.
    > I don't know so I passed the question to them.
    I got an answer here over the holidays and Energy Micro designed the
    part.

    > > I would suggest that you also support the "clock-frequency" and/or
    > > "current-speed" properties that are defined for serial ports, see the
    > > of_serial driver.
    > I will have a look to find out what they mean and update the patch
    > accordingly.
    I took that look and I don't understand what they are good for in my
    case.
    clock-frequency is used to initialize port->uartclk (and helps setting
    up port->custom_divisor if current-speed is given). The driver I posted
    uses the clk API to determine the clock frequency. So shouldn't the frequency
    better be specified in the clk part of the dt? (I don't know yet how a
    dt binding for clks should/can look like, so this is a bit speculative,
    but I'd expect to have nothing more clk related in a device
    specification but a reference to a clk definition.)

    Independant of my driver I wonder if defining current-speed should also
    result in

    port->flags |= UPF_SPD_CUST;

    (in of_platform_serial_setup()).

    Having said that and taking into account that my driver doesn't use
    port->custom_divisor, do you keep suggesting that I should use
    "clock-frequency" and/or "current-speed"?

    Best regards
    Uwe

    --
    Pengutronix e.K. | Uwe Kleine-König |
    Industrial Linux Solutions | http://www.pengutronix.de/ |
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