ARM: dt: fix up PL011 device tree bindings

Make the map match the reality, the current binding text is
nonsense:

- The clock required for the clocking of the serial port
  must come first and is not optional (as the driver will
  otherwise proceed to grab and use the apb_pclk as uartclk),
  and the apb_pclk that clocks the logic must come second
  as the code will retrieve the first clock by index,
  whereas the PrimeCell but will explicitly look for
  "apb_pclk" so this can be specified later, as it is
  looked up by name.

- The pin control state "default" is the only mandated
  state, the sleep state is entirely optional.

We also add an example to avoid further confusion.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
This commit is contained in:
Linus Walleij 2014-05-12 11:37:17 +02:00 committed by Grant Likely
parent e99010edb3
commit a81a6c654b
1 changed files with 25 additions and 3 deletions

View File

@ -6,12 +6,34 @@ Required properties:
- interrupts: exactly one interrupt specifier
Optional properties:
- pinctrl: When present, must have one state named "sleep"
and one state named "default"
- clocks: When present, must refer to exactly one clock named
- pinctrl: When present, must have one state named "default",
and may contain a second name named "sleep". The former
state sets up pins for ordinary operation whereas
the latter state will put the associated pins to sleep
when the UART is unused
- clocks: When present, the first clock listed must correspond to
the clock named UARTCLK on the IP block, i.e. the clock
to the external serial line, whereas the second clock
must correspond to the PCLK clocking the internal logic
of the block. Just listing one clock (the first one) is
deprecated.
- clocks-names: When present, the first clock listed must be named
"uartclk" and the second clock listed must be named
"apb_pclk"
- dmas: When present, may have one or two dma channels.
The first one must be named "rx", the second one
must be named "tx".
See also bindings/arm/primecell.txt
Example:
uart@80120000 {
compatible = "arm,pl011", "arm,primecell";
reg = <0x80120000 0x1000>;
interrupts = <0 11 IRQ_TYPE_LEVEL_HIGH>;
dmas = <&dma 13 0 0x2>, <&dma 13 0 0x0>;
dma-names = "rx", "tx";
clocks = <&foo_clk>, <&bar_clk>;
clock-names = "uartclk", "apb_pclk";
};