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flexcan: Fix up fsl-flexcan device tree binding.
This patch cleans up the documentation of the device-tree binding for the Flexcan devices on Freescale's PowerPC and ARM cores. Extra properties are not used by the driver so we are removing them. Signed-off-by: Robin Holt <holt@sgi.com> Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>, Acked-by: Wolfgang Grandegger <wg@grandegger.com>, Cc: U Bhaskar-B22300 <B22300@freescale.com> Cc: Scott Wood <scottwood@freescale.com> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: socketcan-core@lists.berlios.de, Cc: netdev@vger.kernel.org, Cc: PPC list <linuxppc-dev@lists.ozlabs.org> Cc: devicetree-discuss@lists.ozlabs.org Signed-off-by: David S. Miller <davem@davemloft.net>
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Documentation/devicetree/bindings/net/can/fsl-flexcan.txt
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -1,61 +1,22 @@ | ||
CAN Device Tree Bindings | ||
------------------------ | ||
2011 Freescale Semiconductor, Inc. | ||
Flexcan CAN contoller on Freescale's ARM and PowerPC system-on-a-chip (SOC). | ||
|
||
fsl,flexcan-v1.0 nodes | ||
----------------------- | ||
In addition to the required compatible-, reg- and interrupt-properties, you can | ||
also specify which clock source shall be used for the controller. | ||
Required properties: | ||
|
||
CPI Clock- Can Protocol Interface Clock | ||
This CLK_SRC bit of CTRL(control register) selects the clock source to | ||
the CAN Protocol Interface(CPI) to be either the peripheral clock | ||
(driven by the PLL) or the crystal oscillator clock. The selected clock | ||
is the one fed to the prescaler to generate the Serial Clock (Sclock). | ||
The PRESDIV field of CTRL(control register) controls a prescaler that | ||
generates the Serial Clock (Sclock), whose period defines the | ||
time quantum used to compose the CAN waveform. | ||
- compatible : Should be "fsl,<processor>-flexcan" | ||
|
||
Can Engine Clock Source | ||
There are two sources for CAN clock | ||
- Platform Clock It represents the bus clock | ||
- Oscillator Clock | ||
An implementation should also claim any of the following compatibles | ||
that it is fully backwards compatible with: | ||
|
||
Peripheral Clock (PLL) | ||
-------------- | ||
| | ||
--------- ------------- | ||
| |CPI Clock | Prescaler | Sclock | ||
| |---------------->| (1.. 256) |------------> | ||
--------- ------------- | ||
| | | ||
-------------- ---------------------CLK_SRC | ||
Oscillator Clock | ||
- fsl,p1010-flexcan | ||
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||
- fsl,flexcan-clock-source : CAN Engine Clock Source.This property selects | ||
the peripheral clock. PLL clock is fed to the | ||
prescaler to generate the Serial Clock (Sclock). | ||
Valid values are "oscillator" and "platform" | ||
"oscillator": CAN engine clock source is oscillator clock. | ||
"platform" The CAN engine clock source is the bus clock | ||
(platform clock). | ||
- reg : Offset and length of the register set for this device | ||
- interrupts : Interrupt tuple for this device | ||
|
||
- fsl,flexcan-clock-divider : for the reference and system clock, an additional | ||
clock divider can be specified. | ||
- clock-frequency: frequency required to calculate the bitrate for FlexCAN. | ||
Example: | ||
|
||
Note: | ||
- v1.0 of flexcan-v1.0 represent the IP block version for P1010 SOC. | ||
- P1010 does not have oscillator as the Clock Source.So the default | ||
Clock Source is platform clock. | ||
Examples: | ||
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||
can0@1c000 { | ||
compatible = "fsl,flexcan-v1.0"; | ||
can@1c000 { | ||
compatible = "fsl,p1010-flexcan"; | ||
reg = <0x1c000 0x1000>; | ||
interrupts = <48 0x2>; | ||
interrupt-parent = <&mpic>; | ||
fsl,flexcan-clock-source = "platform"; | ||
fsl,flexcan-clock-divider = <2>; | ||
clock-frequency = <fixed by u-boot>; | ||
}; |
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