src/main/scala/devices/i2c/I2C.scala

   1 // See LICENSE for license details.
   2 package sifive.blocks.devices.i2c
   3
   4 import Chisel._
   5 import config._
   6 import regmapper._
   7 import uncore.tilelink2._
   8 import rocketchip.PeripheryBusConfig
   9 import util.AsyncResetRegVec
  10 import sifive.blocks.devices.gpio.{GPIOPinCtrl}
  11
  12 case class I2CConfig(address: BigInt)
  13
  14 trait HasI2CParameters {
  15   implicit val p: Parameters
  16   val params: I2CConfig
  17   val c = params
  18 }
  19
  20 class I2CPin extends Bundle {
  21   val in  = Bool(INPUT)
  22   val out = Bool(OUTPUT)
  23   val oe  = Bool(OUTPUT)
  24 }
  25
  26 class I2CPort extends Bundle {
  27   val scl = new I2CPin
  28   val sda = new I2CPin
  29 }
  30
  31 trait I2CBundle extends Bundle with HasI2CParameters {
  32   val port = new I2CPort
  33 }
  34
  35 trait I2CModule extends Module with HasI2CParameters with HasRegMap {
  36   val io: I2CBundle
  37
  38   val prescaler_lo = Reg(UInt(8.W))  // low byte clock prescaler register
  39   val prescaler_hi = Reg(UInt(8.W))  // high byte clock prescaler register
  40   val control      = Reg(UInt(8.W))  // control register
  41   val data         = Reg(UInt(8.W))  // write: transmit byte, read: receive byte
  42   val cmd_status   = Reg(UInt(8.W))  // write: command, read: status
  43
  44   // Note that these are out of order.
  45   regmap(
  46     I2CCtrlRegs.prescaler_lo -> Seq(RegField(8, prescaler_lo)),
  47     I2CCtrlRegs.prescaler_hi -> Seq(RegField(8, prescaler_hi)),
  48     I2CCtrlRegs.control      -> Seq(RegField(8, control)),
  49     I2CCtrlRegs.data         -> Seq(RegField(8, data)),
  50     I2CCtrlRegs.cmd_status   -> Seq(RegField(8, cmd_status))
  51   )
  52 }
  53
  54 // Magic TL2 Incantation to create a TL2 Slave
  55 class TLI2C(c: I2CConfig)(implicit p: Parameters)
  56   extends TLRegisterRouter(c.address, interrupts = 1, beatBytes = p(PeripheryBusConfig).beatBytes)(
  57   new TLRegBundle(c, _)    with I2CBundle)(
  58   new TLRegModule(c, _, _) with I2CModule)