Hi Rob,
Am 22.03.2017 um 21:32 schrieb Rob Herring:
> On Mon, Mar 13, 2017 at 11:16 AM, Stefan Wahren <stefan.wahren@xxxxxxxx> wrote:
>> Hi Rob,
>>
>> since serdev has been merged, i'm currently working on a
>> suitable ethernet driver for the QCA7000 [1]. In order to provide a plug
>> and play solution for the network interface i suggest the following
>> binding, which uses common properties for UART configuration:
>>
>> * Qualcomm QCA7000 (Ethernet over UART protocol)
>>
>> Note: The QCA7000 is also useable as a UART slave device.
> Should this be s/UART/SPI/ ?
i rewrote this note in my second version below.
>
>> Required properties:
>> - compatible : Should be "qca,qca7000-uart"
>>
>> Optional properties:
>> - local-mac-address : 6 bytes, Specifies MAC address
>> - current-speed : Specifies current serial device speed in
>> bits per second (default = 115200)
>> - data-bits : Specifies number of data bits (default = 8)
>> - use-parity : If present, this enables the parity
>> error detection (default = off)
>> - odd-parity : If present, this specifies that the parity
>> of each character must be odd (default = even)
>>
>> Example:
>>
>> /* Freescale i.MX28 UART */
>> auart0: serial@8006a000 {
>> compatible = "fsl,imx28-auart", "fsl,imx23-auart";
>> reg = <0x8006a000 0x2000>;
>> pinctrl-names = "default";
>> pinctrl-0 = <&auart0_2pins_a>;
>> status = "okay";
>>
>> qca7000: ethernet {
>> compatible = "qca,qca7000-uart";
>> local-mac-address = [ A0 B0 C0 D0 E0 F0 ];
>> current-speed = <38400>;
> Unless this device supports auto-baud (generally only AT command set
> devices do), this is setup by a bootloader (and you have no way to
> reset the device), or the speed changes with different firmware, I
> don't think you should need this. Devices typically have a fixed,
> initial baudrate that is known, so the driver should know it.
Unfortunately the QCA7000 firmware can be freely preconfigured to a
fixed baudrate and there is no way to determine, because Ethernet frames
are send nearly directly to the UART and vice versa. I agree this isn't
best practice.
>> data-bits = <8>;
> Nearly everything uses 8 bits, so this should be the default.
I will drop it completly.
>
>> use-parity;
>> odd-parity;
> I don't think we need 2 properties here. "even-parity" and
> "odd-parity" booleans should be enough to enable and set parity type.
Your suggestion is better, but it's possible to define wrongly both
which isn't nice per design.
Anyway i decide to drop this, too. So it could be implemented later.
So here is the new version:
* Qualcomm QCA7000 (Ethernet over UART protocol)
Note: This binding applies in case the QCA7000 is configured as a
UART slave device. It is possible to preconfigure the UART settings
of the QCA7000 firmware, which can't be changed during runtime.
Required properties:
- compatible : Should be "qca,qca7000-uart"
Optional properties:
- local-mac-address : 6 bytes, Specifies MAC address
- current-speed : Specifies the serial device speed in
bits per second (default = 115200), which is
predefined by the QCA7000 firmware configuration
Example:
/* Freescale i.MX28 UART */
auart0: serial@8006a000 {
compatible = "fsl,imx28-auart", "fsl,imx23-auart";
reg = <0x8006a000 0x2000>;
pinctrl-names = "default";
pinctrl-0 = <&auart0_2pins_a>;
status = "okay";
qca7000: ethernet {
compatible = "qca,qca7000-uart";
local-mac-address = [ A0 B0 C0 D0 E0 F0 ];
current-speed = <38400>;
};
};
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