On Fri, Jul 22, 2016 at 10:55 PM, Linus Walleij
<linus.walleij@xxxxxxxxxx> wrote:
> On Thu, Jul 14, 2016 at 1:47 PM, Oleksij Rempel <linux@xxxxxxxxxxxxxxxx> wrote:
>
>> This names the GPIO lines on the Banana Pi board in accordance with
>> the A20_Banana_Pi v1.4 Specification.
>>
>> This will make these line names reflect through to userspace
>> so that they can easily be identified and used with the new
>> character device ABI.
>>
>> Some care has been taken to name all lines, not just those used
>> by the external connectors, also lines that are muxed into some
>> other function than GPIO: these are named "[FOO]" so that users
>> can see with lsgpio what all lines are used for.
>>
>> Ps: most of the text was taken from Linux Wallej patch.
>
> LinuS
>
>>
>> Cc: devicetree@xxxxxxxxxxxxxxx
>> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>> Cc: Chen-Yu Tsai <wens@xxxxxxxx>
>> Signed-off-by: Oleksij Rempel <linux@xxxxxxxxxxxxxxxx>
>
> Nice usecase!
>
>> + /*
>> + * Legend: proper name = the GPIO line is used as GPIO
>> + * NC = not connected (not routed from the SoC)
>> + * "[PER]" = pin is muxed for peripheral (not GPIO)
>> + * "" = no idea, schematic doesn't say, could be
>> + * unrouted (not connected to any external pin)
>> + * LSEC = Low Speed External Connector
>> + * HSEC = High Speed External Connector
I don't see LSEC/HSEC used anywhere?
>> + */
>
> So maybe we should make this naming convention a suggested
> standard. People seem to like it.
One question about this whole thing: how extensively should we add
the names? Only for exposed pins? Or every pin that's routed/used?
>> + gpio-line-names =
>> + /* PA */
>> + "[ERXD3]", "[ERXD2]", "[ERXD1]", "[ERXD0]", "[ETXD3]",
>> + "[ETXD2]", "[ETXD1]", "[ETXD0]",
>> + "[ERXCK]", "[ERXERR]", "[ERXDV]", "[EMDC]", "[EMDIO]",
>> + "[ETXEN]", "[ETXCK]", "[ECRS]",
>> + "[ECOL]", "[ETXERR]", "", "", "", "", "", "",
>> + "", "", "", "", "", "", "", "",
>> + /* PB */
>> + "[PMU-SCK]", "[PMU-SDA]", "", "", "", "NC", "NC", "NC",
>> + "NC", "[USB0-DRV]", "NC", "NC", "NC", "NC", "", "",
>> + "", "", "", "", "SCL", "SDA", "", "",
>
> Are these bit-banged SCL and SDA for doing I2C with
> GPIO? Otherwise you probably want to name them "[SCL]" and "[SDA]"
There's an actual I2C controller backing them.
>
>> + "TXD0", "RXD0", "IO-1", "PH3", "[USB0-IDDET]", "PH5", "", "",
>
> Same here. You probably want "[TXD0]" etc unless you're bit-banging
> the serial port. "IO-1" sounds like a real GPIO though and should
> probably be named like that without [] and "PH3" what is that really?
> A device-muxed pin or some kind of GPIO?
PH3 is actually the pin name. The vendor uses "IO-7" and "IO-8" as function
names for PH3 and PH5, but actually names them "NC":
http://www.bananapi.org/p/product.html
>
>> + "", "", "[SD0-DET]", "", "", "", "", "",
>> + "NC", "", "", "", "IO-4", "IO-5", "NC", "[EMAC-PWR-EN]",
>
> So these seem correct too.
>
>> + "[LED1]", "NC", "NC", "NC", "", "", "", "",
>
> "LED1" seems like the right name, if this is a GPIO used to drive
> a LED.
This is GPIO based.
>
>> + "", "", "", "IO-GCLK", "NC", "NC", "NC", "NC",
>
> WHat is IO-GCLK? A real GPIO line used for toggling a clock?
> Or a hardware clock signal? In the first case it it correctly named,
> in the other case it should be "[IO-GCLK]".
According to the schematics this is a PWM output.
Regards
ChenYu
>
>> + "NC", "NC", "[SPI-CE0]", "[SPI-CLK]", "[SPI-MOSI]",
>> + "[SPI-MISO]", "[SPI-CE1]", "NC",
>> + "IO-6", "IO-3", "IO-2", "IO-0", "", "", "", "",
>
> Looks right.
>
> Yours,
> Linus Walleij
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