Refactor and improve PMIC configuration

* Add PMIC.h and PMIC.cpp for general PMIC support in variants.

* Add BQ24195.h with register addresses and definitions for
BQ24195/BQ24195L devices.

* Add setupPMIC function to provide consistent initialization,
including:
    * Disable I2C watchdog timer to keep device in 'host' mode.
    * Disable charging when no battery present.
    * Disable charging system safety timer when no battery present.
    * Disable battery FET when no battery present.
    * Enable USB D+/D- on boards where they are connected to PMIC.
    * Enable 2A input current limit and 3.88V input voltage limit,
      to enable high-speed battery charging.

* Update all variants with BQ24195 devices to use setupPMIC function.

Results:

* STAT LED no longer blinks on devices without batteries (was caused
by charging system safety timer expiration).

* Charging is actually disabled on boards without batteries (previously
it was left as the default, which is 'enabled' in these PMICs).

* Charging speed is dramatically increased (assumes 2A USB power supply
is used to power board; MKR GSM 1400 previously assumed 3A power supply).

cores/arduino/PMIC.cpp

@@ -0,0 +1,79 @@
+/*
+  PMIC.cpp - initialization of Power Management ICs
+  Copyright (c) 2020 Kevin P. Fleming.  All right reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include "Arduino.h"
+
+#ifdef USE_BQ24195L_PMIC
+
+#include "PMIC/BQ24195.h"
+
+#include "wiring_private.h"
+
+void setupPMIC(SERCOM& sercom, bool batteryPresent, bool USBDetect) {
+  BQ24195_REG00 reg00;
+  reg00.IINLIM = 0b110; // input current limit 2A
+  reg00.VINDPM = 0b0000; // input voltage limit 3.88V
+  reg00.EN_HIZ = 0b0; // disable
+
+  sercom.startTransmissionWIRE(BQ24195_ADDRESS, WIRE_WRITE_FLAG);
+  sercom.sendDataMasterWIRE(BQ24195_REG00_ADDRESS);
+  sercom.sendDataMasterWIRE(reg00.val);
+  sercom.prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
+
+  BQ24195_REG01 reg01;
+  reg01.RSVD = 0b1;
+  reg01.SYS_MIN = 0b101; // minimum system voltage 3.5V
+  reg01.CHG_CONFIG_ENABLE = (batteryPresent ? 0b1 : 0b0); // battery charge enable/disable
+  reg01.CHG_CONFIG_OTG = 0b0;
+  reg01.WATCHDOG_TIMER_RESET = 0b1; // reset watchdog timer
+  reg01.REGISTER_RESET = 0b0; // keep current register setting
+
+  sercom.startTransmissionWIRE(BQ24195_ADDRESS, WIRE_WRITE_FLAG);
+  sercom.sendDataMasterWIRE(BQ24195_REG01_ADDRESS);
+  sercom.sendDataMasterWIRE(reg01.val);
+  sercom.prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
+
+  BQ24195_REG05 reg05;
+  reg05.RSVD = 0b0;
+  reg05.CHG_TIMER = 0b01; // fast charge timer 8 hours
+  reg05.EN_TIMER = (batteryPresent ? 0b1 : 0b0); // enable/disable charge safety timer
+  reg05.WATCHDOG = 0b00; // disable watchdog timer to stay in host mode
+  reg05.TERM_STAT = 0b0; // charge termination indicator match ITERM
+  reg05.EN_TERM = 0b1; // enable charge termination
+
+  sercom.startTransmissionWIRE(BQ24195_ADDRESS, WIRE_WRITE_FLAG);
+  sercom.sendDataMasterWIRE(BQ24195_REG05_ADDRESS);
+  sercom.sendDataMasterWIRE(reg05.val);
+  sercom.prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
+
+  BQ24195_REG07 reg07;
+  reg07.INT_MASK_BAT = 0b1; // INT on battery fault
+  reg07.INT_MASK_CHG = 0b1; // INT on charge fault
+  reg07.RSVD = 0b010;
+  reg07.BATFET_DISABLE = (batteryPresent ? 0b0 : 0b1); // battery FET enable/disable
+  reg07.TMR2X_EN = 0b0; // safety timer not slowed by 2X
+  reg07.DPDM_EN = (USBDetect ? 0b1 : 0b0); // D+/D- detection enable/disable
+
+  sercom.startTransmissionWIRE(BQ24195_ADDRESS, WIRE_WRITE_FLAG);
+  sercom.sendDataMasterWIRE(BQ24195_REG07_ADDRESS);
+  sercom.sendDataMasterWIRE(reg07.val);
+  sercom.prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
+}
+
+#endif

cores/arduino/PMIC.h

@@ -0,0 +1,24 @@
+/*
+  PMIC.h - initialization of Power Management ICs
+  Copyright (c) 2020 Kevin P. Fleming.  All right reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#pragma once
+
+#include "Arduino.h"
+
+extern void setupPMIC(SERCOM& sercom, bool batteryPresent, bool USBDetect);

cores/arduino/PMIC/BQ24195.h

@@ -0,0 +1,178 @@
+/*
+  BQ24195.h - Register definitions for BQ24195/BQ24195L PMICs.
+  Copyright (c) 2020 Kevin P. Fleming.  All right reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the GNU Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef union {
+  struct {
+    uint8_t IINLIM:3;
+    uint8_t VINDPM:4;
+    uint8_t EN_HIZ:1;
+  };
+  uint8_t val;
+} BQ24195_REG00;
+
+static_assert(sizeof(BQ24195_REG00) == 1, "BQ24195_REG00 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t RSVD:1;
+    uint8_t SYS_MIN:3;
+    uint8_t CHG_CONFIG_ENABLE:1;
+    uint8_t CHG_CONFIG_OTG:1;
+    uint8_t WATCHDOG_TIMER_RESET:1;
+    uint8_t REGISTER_RESET:1;
+  };
+  uint8_t val;
+} BQ24195_REG01;
+
+static_assert(sizeof(BQ24195_REG01) == 1, "BQ24195_REG01 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t FORCE_20PCT:1;
+    uint8_t RSVD:1;
+    uint8_t ICHG:6;
+  };
+  uint8_t val;
+} BQ24195_REG02;
+
+static_assert(sizeof(BQ24195_REG02) == 1, "BQ24195_REG02 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t ITERM:4;
+    uint8_t IPRECHG:4;
+  };
+  uint8_t val;
+} BQ24195_REG03;
+
+static_assert(sizeof(BQ24195_REG03) == 1, "BQ24195_REG03 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t VRECHG:1;
+    uint8_t BATLOWV:1;
+    uint8_t VREG:6;
+  };
+  uint8_t val;
+} BQ24195_REG04;
+
+static_assert(sizeof(BQ24195_REG04) == 1, "BQ24195_REG04 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t RSVD:1;
+    uint8_t CHG_TIMER:2;
+    uint8_t EN_TIMER:1;
+    uint8_t WATCHDOG:2;
+    uint8_t TERM_STAT:1;
+    uint8_t EN_TERM:1;
+  };
+  uint8_t val;
+} BQ24195_REG05;
+
+static_assert(sizeof(BQ24195_REG05) == 1, "BQ24195_REG05 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t VRECHG:1;
+    uint8_t BATLOWV:1;
+    uint8_t VREG:6;
+  };
+  uint8_t val;
+} BQ24195_REG06;
+
+static_assert(sizeof(BQ24195_REG06) == 1, "BQ24195_REG06 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t INT_MASK_BAT:1;
+    uint8_t INT_MASK_CHG:1;
+    uint8_t RSVD:3;
+    uint8_t BATFET_DISABLE:1;
+    uint8_t TMR2X_EN:1;
+    uint8_t DPDM_EN:1;
+  };
+  uint8_t val;
+} BQ24195_REG07;
+
+static_assert(sizeof(BQ24195_REG07) == 1, "BQ24195_REG07 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t VSYS_STAT:1;
+    uint8_t THERM_STAT:1;
+    uint8_t PG_STAT:1;
+    uint8_t DPM_STAT:1;
+    uint8_t CHRG_STAT:2;
+    uint8_t VBUS_STAT:2;
+  };
+  uint8_t val;
+} BQ24195_REG08;
+
+static_assert(sizeof(BQ24195_REG08) == 1, "BQ24195_REG08 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t NTC_FAULT:3;
+    uint8_t BAT_FAULT:1;
+    uint8_t CHRG_FAULT:2;
+    uint8_t RSVD:1;
+    uint8_t WATCHDOG_FAULT:1;
+  };
+  uint8_t val;
+} BQ24195_REG09;
+
+static_assert(sizeof(BQ24195_REG09) == 1, "BQ24195_REG09 union size is incorrect, should be 1 byte.");
+
+typedef union {
+  struct {
+    uint8_t DEV_REG:2;
+    uint8_t TS_PROFILE:1;
+    uint8_t PN:3;
+    uint8_t RSVD:2;
+  };
+  uint8_t val;
+} BQ24195_REG0A;
+
+static_assert(sizeof(BQ24195_REG0A) == 1, "BQ24195_REG0A union size is incorrect, should be 1 byte.");
+
+#define BQ24195_ADDRESS		0x6B
+#define BQ24195_REG00_ADDRESS	0x00
+#define BQ24195_REG01_ADDRESS	0x01
+#define BQ24195_REG02_ADDRESS	0x02
+#define BQ24195_REG03_ADDRESS	0x03
+#define BQ24195_REG04_ADDRESS	0x04
+#define BQ24195_REG05_ADDRESS	0x05
+#define BQ24195_REG06_ADDRESS	0x06
+#define BQ24195_REG07_ADDRESS	0x07
+#define BQ24195_REG08_ADDRESS	0x08
+#define BQ24195_REG09_ADDRESS	0x09
+#define BQ24195_REG0A_ADDRESS	0x0A
+
+#ifdef __cplusplus
+} // extern "C"
+#endif

variants/mkrgsm1400/variant.cpp

@@ -177,76 +177,28 @@ SERCOM sercom3(SERCOM3);
 SERCOM sercom4(SERCOM4);
 SERCOM sercom5(SERCOM5);
 
-#if defined(USE_BQ24195L_PMIC)
-
+#ifdef USE_BQ24195L_PMIC
+#include "PMIC.h"
 #include "wiring_private.h"
-
-#define PMIC_ADDRESS  0x6B
-#define PMIC_REG01    0x01
-#define PMIC_REG07    0x07
-
-#define PMIC_REG00    0x00
-
-static inline void set_voltage_current_thresholds() {
-  PERIPH_WIRE.initMasterWIRE(100000);
-  PERIPH_WIRE.enableWIRE();
-  pinPeripheral(PIN_WIRE_SDA, g_APinDescription[PIN_WIRE_SDA].ulPinType);
-  pinPeripheral(PIN_WIRE_SCL, g_APinDescription[PIN_WIRE_SCL].ulPinType);
-
-  PERIPH_WIRE.startTransmissionWIRE( PMIC_ADDRESS, WIRE_WRITE_FLAG );
-  PERIPH_WIRE.sendDataMasterWIRE(PMIC_REG00);
-  PERIPH_WIRE.sendDataMasterWIRE(0x07);  // input voltage limit = 3.88V, input current limit = 3A
-  PERIPH_WIRE.prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
-
-  PERIPH_WIRE.disableWIRE();
-}
-
-static inline void enable_battery_charging() {
-  PERIPH_WIRE.initMasterWIRE(100000);
-  PERIPH_WIRE.enableWIRE();
-  pinPeripheral(PIN_WIRE_SDA, g_APinDescription[PIN_WIRE_SDA].ulPinType);
-  pinPeripheral(PIN_WIRE_SCL, g_APinDescription[PIN_WIRE_SCL].ulPinType);
-
-  PERIPH_WIRE.startTransmissionWIRE( PMIC_ADDRESS, WIRE_WRITE_FLAG );
-  PERIPH_WIRE.sendDataMasterWIRE(PMIC_REG01);
-  PERIPH_WIRE.sendDataMasterWIRE(0x1B); // Charge Battery + Minimum System Voltage 3.5V
-  PERIPH_WIRE.prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
-
-  PERIPH_WIRE.disableWIRE();
-}
-
-static inline void disable_battery_fet(bool disabled) {
-  PERIPH_WIRE.initMasterWIRE(100000);
-  PERIPH_WIRE.enableWIRE();
-  pinPeripheral(PIN_WIRE_SDA, g_APinDescription[PIN_WIRE_SDA].ulPinType);
-  pinPeripheral(PIN_WIRE_SCL, g_APinDescription[PIN_WIRE_SCL].ulPinType);
-
-  PERIPH_WIRE.startTransmissionWIRE( PMIC_ADDRESS, WIRE_WRITE_FLAG );
-  PERIPH_WIRE.sendDataMasterWIRE(PMIC_REG07);
-  // No D+/D– detection + Safety timer not slowed by 2X during input DPM or thermal regulation +
-  // BAT fet disabled/enabled + charge and bat fault INT
-  PERIPH_WIRE.sendDataMasterWIRE(0x0B | (disabled ? 0x20 : 0x00));
-  PERIPH_WIRE.prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
-
-  PERIPH_WIRE.disableWIRE();
-}
-
 #endif
 
 void initVariant() {
-#if defined(USE_BQ24195L_PMIC)
+#ifdef USE_BQ24195L_PMIC
   pinMode(ADC_BATTERY, OUTPUT);
   digitalWrite(ADC_BATTERY, LOW);
   delay(10);
   pinMode(ADC_BATTERY, INPUT);
   delay(100);
 
+  PERIPH_WIRE.initMasterWIRE(100000);
+  PERIPH_WIRE.enableWIRE();
+  pinPeripheral(PIN_WIRE_SDA, g_APinDescription[PIN_WIRE_SDA].ulPinType);
+  pinPeripheral(PIN_WIRE_SCL, g_APinDescription[PIN_WIRE_SCL].ulPinType);
+
   bool batteryPresent = analogRead(ADC_BATTERY) > 600;
-  if (batteryPresent) {
-    enable_battery_charging();
-  }
-  disable_battery_fet(!batteryPresent);
-  set_voltage_current_thresholds();
+  setupPMIC(PERIPH_WIRE, batteryPresent, true);
+
+  PERIPH_WIRE.disableWIRE();
 #endif
 
   // put GSM modem in reset on start to conserve power if it's not used