1 files changed, 114 insertions, 0 deletions
diff --git a/hsm-ina226/Hsm/INA226.hs b/hsm-ina226/Hsm/INA226.hs
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+++ b/hsm-ina226/Hsm/INA226.hs
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+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TypeFamilies #-}
+
+module Hsm.INA226
+  ( INA226
+  , INA226Reading (..)
+  , INA226Path
+  , INA226Addr
+  , readINA226State
+  , runINA226
+  )
+where
+
+import Data.Word (Word16, Word8)
+import Effectful (Dispatch (Static), DispatchOf, Eff, IOE, (:>))
+import Effectful.Dispatch.Static (SideEffects (WithSideEffects), StaticRep, evalStaticRep)
+import Hsm.Core.Show (showHex)
+import Hsm.I2C (I2C, readInt16, readWord16, writeWord16)
+import Hsm.Log (Logs, Severity (Info, Trace), logMsg)
+
+data INA226 (a :: * -> *) (b :: *)
+
+type instance DispatchOf INA226 = Static WithSideEffects
+
+newtype instance StaticRep INA226
+  = INA226 ()
+
+data INA226Reading = INA226Reading
+  { voltage :: Float
+  , current :: Float
+  , power :: Float
+  }
+  deriving Show
+
+-- INA226 I2C device path and address
+type INA226Path = "/dev/i2c-0"
+
+type INA226Addr = 64
+
+-- INA226 registers
+configurationReg :: Word8
+configurationReg = 0x00
+
+busVoltageReg :: Word8
+busVoltageReg = 0x02
+
+powerReg :: Word8
+powerReg = 0x03
+
+currentReg :: Word8
+currentReg = 0x04
+
+calibratonReg :: Word8
+calibratonReg = 0x05
+
+manufacturerIdReg :: Word8
+manufacturerIdReg = 0xfe
+
+dieIdReg :: Word8
+dieIdReg = 0xff
+
+-- Configuration and calibration constants
+-- For reference, data sheet can be found here:
+-- https://www.ti.com/lit/ds/symlink/ina226.pdf
+reset :: Word16
+reset = 0b1000000000000000
+
+-- Average values over 16 samples
+-- Use a 1.1ms conversion time for bus voltage and shunt voltage readings
+-- Use continuous shunt and bus voltage operating mode
+configuration :: Word16
+configuration = 0b0000010100100111
+
+-- Decide LSB for current readings based on expected max current:
+-- CurrentLSB == max_expected_current / 2^15 == 5A / 2^15 == 0.2mA/bit (rounded up)
+currentLSB :: Float
+currentLSB = 0.0002
+
+-- PowerLSB = CurrentLSB * 25
+powerLSB :: Float
+powerLSB = currentLSB * 25
+
+-- Calibration == 0.00512 / (CurrentLSB * Rshunt) == 0.00512 / (0.0002 * 0.002) == 12800
+calibration :: Word16
+calibration = 12800
+
+-- Voltage LSB is fixed
+busVoltageLSB :: Float
+busVoltageLSB = 0.00125
+
+-- Read INA226 voltage/current/power registers
+readINA226State :: (I2C INA226Path INA226Addr :> es, INA226 :> es, Logs '["i2c", "ina226"] es) => Eff es INA226Reading
+readINA226State = do
+  logMsg @"ina226" Trace "Reading INA226 state registers"
+  voltage <- (* busVoltageLSB) . fromIntegral <$> readWord16 busVoltageReg
+  current <- (* currentLSB) . fromIntegral <$> readInt16 currentReg
+  power <- (* powerLSB) . fromIntegral <$> readInt16 powerReg
+  return INA226Reading{..}
+
+runINA226
+  :: (I2C INA226Path INA226Addr :> es, IOE :> es, Logs '["i2c", "ina226"] es) => Eff (INA226 : es) a -> Eff es a
+runINA226 action = do
+  -- Prepare chip
+  writeWord16 configurationReg reset
+  writeWord16 configurationReg configuration
+  writeWord16 calibratonReg calibration
+  -- Print some stats to the user
+  manId <- readWord16 manufacturerIdReg
+  dieId <- readWord16 dieIdReg
+  cfgReg <- readWord16 configurationReg
+  logMsg @"ina226" Info $ "INA226 manufacturer ID: " <> showHex manId
+  logMsg @"ina226" Info $ "INA226 die ID: " <> showHex dieId
+  logMsg @"ina226" Info $ "INA226 configuration register: " <> showHex cfgReg
+  evalStaticRep (INA226 ()) action