| # Copyright 2015 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| """Access to Texas Instruments INA3221. |
| Triple-Channel, High-Side Measurement, Shunt and Bus Voltage Monitor |
| with i2c Interface. |
| """ |
| import ina2xx |
| |
| |
| class ina3221(ina2xx.ina2xx): |
| """Object to access drv=ina3221 controls. |
| """ |
| MAX_CHANNEL = 3 |
| REG_IDX = dict(cfg=0, shv=1, busv=2, msken=15) |
| MAX_REG_INDEX = 0x11 # Power valid lower limit. Ignoring Manuf/Die ID |
| |
| MSKEN_CNVR = 0x1 |
| |
| BUSV_MV_PER_LSB = 8 |
| BUSV_MV_OFFSET = 3 |
| BUSV_MAX = 26000 |
| |
| SHV_UV_PER_LSB = 40.0 |
| SHV_OFFSET = 3 |
| SHV_MASK = 0x7ff8 |
| |
| def _read_cnvr_ovf(self): |
| """Read mask/enable register and return needed values. |
| |
| Returns: |
| tuple (is_cnvr, is_ovf, voltage) where: |
| is_cnvr: boolean True if conversion ready else False |
| is_ovf: boolean True if math overflow occurred else False |
| """ |
| msken_reg = self._read_reg(self.REG_MSKEN) |
| is_cnvr = (self.MSKEN_CNVR & msken_reg) != 0 |
| return (is_cnvr, 0) |
