From b156d18bc25b89822f83a39046d6f5a1afd3464a Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jeremy@system76.com>
Date: Tue, 29 Dec 2020 10:15:26 -0700
Subject: [PATCH] system76/common: Add OZ26786 charger

---
 src/board/system76/common/charger/oz26786.c | 142 ++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 src/board/system76/common/charger/oz26786.c

diff --git a/src/board/system76/common/charger/oz26786.c b/src/board/system76/common/charger/oz26786.c
new file mode 100644
index 0000000..5792ca4
--- /dev/null
+++ b/src/board/system76/common/charger/oz26786.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-3.0-only
+//
+// O2 Micro OZ26786
+// No public datasheet
+
+#include <board/battery.h>
+#include <board/smbus.h>
+#include <common/debug.h>
+#include <common/macro.h>
+
+// Registers
+#define REG_CHARGE_CURRENT 0x14
+#define REG_CHARGE_VOLTAGE 0x15
+#define REG_CHARGE_OPTION_1 0x3D
+    #define CHARGE_OPTION_1_600KHZ BIT(11)
+#define REG_CHARGE_OPTION_2 0x3B
+    #define CHARGE_OPTION_2_PSYS_EN BIT(11)
+#define REG_ADAPTER_CURRENT 0x3F
+
+// XXX: Assumption: ac_last is initialized high.
+static bool charger_enabled = false;
+
+int battery_charger_disable(void) {
+    int res = 0;
+
+    if (!charger_enabled) return 0;
+
+    // Set charge option 1 to converter frequency 600 KHz
+    //TODO: needed when charging disabled?
+    res = smbus_write(
+        CHARGER_ADDRESS,
+        REG_CHARGE_OPTION_1,
+        CHARGE_OPTION_1_600KHZ
+    );
+    if (res < 0) return res;
+
+    // Set charge option 2 to PSYS enable
+    //TODO: needed when charging disabled?
+    res = smbus_write(
+        CHARGER_ADDRESS,
+        REG_CHARGE_OPTION_2,
+        CHARGE_OPTION_2_PSYS_EN
+    );
+    if (res < 0) return res;
+
+    // Disable charge current
+    res = smbus_write(CHARGER_ADDRESS, REG_CHARGE_CURRENT, 0);
+    if (res < 0) return res;
+
+    // Disable charge voltage
+    res = smbus_write(CHARGER_ADDRESS, REG_CHARGE_VOLTAGE, 0);
+    if (res < 0) return res;
+
+    // Set input current in mA
+    //TODO: needed when charging disabled?
+    res = smbus_write(CHARGER_ADDRESS, REG_ADAPTER_CURRENT, CHARGER_INPUT_CURRENT);
+    if (res < 0) return res;
+
+    DEBUG("Charger disabled\n");
+    charger_enabled = false;
+    return 0;
+}
+
+int battery_charger_enable(void) {
+    int res = 0;
+
+    if (charger_enabled) return 0;
+
+    res = battery_charger_disable();
+    if (res < 0) return res;
+
+    // Set charge option 1 to converter frequency 600 KHz
+    res = smbus_write(
+        CHARGER_ADDRESS,
+        REG_CHARGE_OPTION_1,
+        CHARGE_OPTION_1_600KHZ
+    );
+    if (res < 0) return res;
+
+    // Set charge option 2 to PSYS enable
+    res = smbus_write(
+        CHARGER_ADDRESS,
+        REG_CHARGE_OPTION_2,
+        CHARGE_OPTION_2_PSYS_EN
+    );
+    if (res < 0) return res;
+
+    // Set charge current in mA
+    res = smbus_write(CHARGER_ADDRESS, REG_CHARGE_CURRENT, CHARGER_CHARGE_CURRENT);
+    if (res < 0) return res;
+
+    // Set charge voltage in mV
+    res = smbus_write(CHARGER_ADDRESS, REG_CHARGE_VOLTAGE, CHARGER_CHARGE_VOLTAGE);
+    if (res < 0) return res;
+
+    // Set input current in mA
+    res = smbus_write(CHARGER_ADDRESS, REG_ADAPTER_CURRENT, CHARGER_INPUT_CURRENT);
+    if (res < 0) return res;
+
+    DEBUG("Charger enabled\n");
+    charger_enabled = true;
+    return 0;
+}
+
+void battery_charger_event(void) {
+    // Avoid watchdog timeout
+    if (charger_enabled) {
+        // Set charge voltage in mV
+        smbus_write(CHARGER_ADDRESS, REG_CHARGE_VOLTAGE, CHARGER_CHARGE_VOLTAGE);
+    }
+}
+
+void battery_debug(void) {
+    uint16_t data = 0;
+    int res = 0;
+
+    #define command(N, A, V) { \
+        DEBUG("  " #N ": "); \
+        res = smbus_read(A, V, &data); \
+        if (res < 0) { \
+            DEBUG("ERROR %04X\n", -res); \
+        } else { \
+            DEBUG("%04X\n", data); \
+        } \
+    }
+
+    DEBUG("Battery:\n");
+    command(Temperature, BATTERY_ADDRESS, 0x08);
+    command(Voltage, BATTERY_ADDRESS, 0x09);
+    command(Current, BATTERY_ADDRESS, 0x0A);
+    command(Charge, BATTERY_ADDRESS, 0x0D);
+    command(Status, BATTERY_ADDRESS, 0x16);
+
+    DEBUG("Charger (oz26786):\n");
+    command(ChargeCurrent, CHARGER_ADDRESS, REG_CHARGE_CURRENT);
+    command(ChargeVoltage, CHARGER_ADDRESS, REG_CHARGE_VOLTAGE);
+    command(ChargeOption_1, CHARGER_ADDRESS, REG_CHARGE_OPTION_1);
+    command(ChargeOption_2, CHARGER_ADDRESS, REG_CHARGE_OPTION_2);
+    command(AdapterCurrent, CHARGER_ADDRESS, REG_ADAPTER_CURRENT);
+
+    #undef command
+}