Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt

   1 * Synopsys DesignWare ABP UART
   2
   3 Required properties:
   4 - compatible : "snps,dw-apb-uart"
   5 - reg : offset and length of the register set for the device.
   6 - interrupts : should contain uart interrupt.
   7
   8 Clock handling:
   9 The clock rate of the input clock needs to be supplied by one of
  10 - clock-frequency : the input clock frequency for the UART.
  11 - clocks : phandle to the input clock
  12
  13 The supplying peripheral clock can also be handled, needing a second property
  14 - clock-names: tuple listing input clock names.
  15         Required elements: "baudclk", "apb_pclk"
  16
  17 Optional properties:
  18 - snps,uart-16550-compatible : reflects the value of UART_16550_COMPATIBLE
  19   configuration parameter. Define this if your UART does not implement the busy
  20   functionality.
  21 - resets : phandle to the parent reset controller.
  22 - reg-shift : quantity to shift the register offsets by.  If this property is
  23   not present then the register offsets are not shifted.
  24 - reg-io-width : the size (in bytes) of the IO accesses that should be
  25   performed on the device.  If this property is not present then single byte
  26   accesses are used.
  27 - dcd-override : Override the DCD modem status signal. This signal will always
  28   be reported as active instead of being obtained from the modem status
  29   register. Define this if your serial port does not use this pin.
  30 - dsr-override : Override the DTS modem status signal. This signal will always
  31   be reported as active instead of being obtained from the modem status
  32   register. Define this if your serial port does not use this pin.
  33 - cts-override : Override the CTS modem status signal. This signal will always
  34   be reported as active instead of being obtained from the modem status
  35   register. Define this if your serial port does not use this pin.
  36 - ri-override : Override the RI modem status signal. This signal will always be
  37   reported as inactive instead of being obtained from the modem status register.
  38   Define this if your serial port does not use this pin.
  39
  40 Example:
  41
  42         uart@80230000 {
  43                 compatible = "snps,dw-apb-uart";
  44                 reg = <0x80230000 0x100>;
  45                 clock-frequency = <3686400>;
  46                 interrupts = <10>;
  47                 reg-shift = <2>;
  48                 reg-io-width = <4>;
  49                 dcd-override;
  50                 dsr-override;
  51                 cts-override;
  52                 ri-override;
  53         };
  54
  55 Example with one clock:
  56
  57         uart@80230000 {
  58                 compatible = "snps,dw-apb-uart";
  59                 reg = <0x80230000 0x100>;
  60                 clocks = <&baudclk>;
  61                 interrupts = <10>;
  62                 reg-shift = <2>;
  63                 reg-io-width = <4>;
  64         };
  65
  66 Example with two clocks:
  67
  68         uart@80230000 {
  69                 compatible = "snps,dw-apb-uart";
  70                 reg = <0x80230000 0x100>;
  71                 clocks = <&baudclk>, <&apb_pclk>;
  72                 clock-names = "baudclk", "apb_pclk";
  73                 interrupts = <10>;
  74                 reg-shift = <2>;
  75                 reg-io-width = <4>;
  76         };