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fde8be2923
The loopback test mode is not implemented in all NS16550 compatible UARTs. The 8250 driver uses the UPF_SKIP_TEST flag to indicate this, however it is not possible to set this flag via device-tree. Add a new 'no-loopback-test' property, and modify the of_serial driver to set the UPF_SKIP_TEST flag if the property is present. Signed-off-by: Gabor Juhos <juhosg@openwrt.org> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
40 lines
1.2 KiB
Plaintext
40 lines
1.2 KiB
Plaintext
* UART (Universal Asynchronous Receiver/Transmitter)
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Required properties:
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- compatible : one of:
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- "ns8250"
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- "ns16450"
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- "ns16550a"
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- "ns16550"
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- "ns16750"
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- "ns16850"
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- "nvidia,tegra20-uart"
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- "nxp,lpc3220-uart"
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- "ibm,qpace-nwp-serial"
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- "serial" if the port type is unknown.
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- reg : offset and length of the register set for the device.
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- interrupts : should contain uart interrupt.
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- clock-frequency : the input clock frequency for the UART.
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Optional properties:
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- current-speed : the current active speed of the UART.
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- reg-offset : offset to apply to the mapbase from the start of the registers.
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- reg-shift : quantity to shift the register offsets by.
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- reg-io-width : the size (in bytes) of the IO accesses that should be
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performed on the device. There are some systems that require 32-bit
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accesses to the UART (e.g. TI davinci).
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- used-by-rtas : set to indicate that the port is in use by the OpenFirmware
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RTAS and should not be registered.
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- no-loopback-test: set to indicate that the port does not implements loopback
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test mode
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Example:
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uart@80230000 {
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compatible = "ns8250";
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reg = <0x80230000 0x100>;
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clock-frequency = <3686400>;
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interrupts = <10>;
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reg-shift = <2>;
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};
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