snps-dw-apb-uart.txt 2.6 KB

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