[RFC 3/4] power: supply: Add charger driver for Rockchip RK817

[Chris Morgan <macroalpha82@gmail.com>]

From: Chris Morgan <macromorgan@hotmail.com>

Add support for the Rockchip rk817 battery charger integrated into the
rk817 PMIC.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/power/supply/Kconfig         |   6 +
 drivers/power/supply/Makefile        |   1 +
 drivers/power/supply/rk817_charger.c | 927 +++++++++++++++++++++++++++
 3 files changed, 934 insertions(+)
 create mode 100644 drivers/power/supply/rk817_charger.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 11f5368e810e..311130da36ff 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -666,6 +666,12 @@ config CHARGER_BQ256XX
 	  charge management and system power path management devices for single
 	  cell Li-ion and Li-polymer batteries.
 
+config CHARGER_RK817
+	tristate "Rockchip RK817 PMIC Battery Charger"
+	depends on MFD_RK808
+	help
+	  Say Y to include support for Rockchip RK817 Battery Charger.
+
 config CHARGER_SMB347
 	tristate "Summit Microelectronics SMB3XX Battery Charger"
 	depends on I2C
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 33059a91f60c..9497d2105712 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_CHARGER_BQ2515X)	+= bq2515x_charger.o
 obj-$(CONFIG_CHARGER_BQ25890)	+= bq25890_charger.o
 obj-$(CONFIG_CHARGER_BQ25980)	+= bq25980_charger.o
 obj-$(CONFIG_CHARGER_BQ256XX)	+= bq256xx_charger.o
+obj-$(CONFIG_CHARGER_RK817)	+= rk817_charger.o
 obj-$(CONFIG_CHARGER_SMB347)	+= smb347-charger.o
 obj-$(CONFIG_CHARGER_TPS65090)	+= tps65090-charger.o
 obj-$(CONFIG_CHARGER_TPS65217)	+= tps65217_charger.o
diff --git a/drivers/power/supply/rk817_charger.c b/drivers/power/supply/rk817_charger.c
new file mode 100644
index 000000000000..4a1bbff9c7c1
--- /dev/null
+++ b/drivers/power/supply/rk817_charger.c
@@ -0,0 +1,927 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Charger Driver for Rockchip rk817
+ *
+ * Copyright (c) 2021
+ *
+ * Authors: Maya Matuszczyk <maccraft123mc@gmail.com>
+ *	    Chris Morgan <macromorgan@hotmail.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/extcon.h>
+#include <linux/fb.h>
+#include <linux/gpio.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/irq.h>
+#include <linux/jiffies.h>
+#include <linux/mfd/rk808.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+#include <linux/power_supply.h>
+
+/* Charging statuses reported by hardware register */
+enum rk817_charge_status {
+	CHRG_OFF,
+	DEAD_CHRG,
+	TRICKLE_CHRG,
+	CC_OR_CV_CHRG,
+	CHARGE_FINISH,
+	USB_OVER_VOL,
+	BAT_TMP_ERR,
+	BAT_TIM_ERR,
+};
+
+/* Max charging current read to/written from hardware register.
+ * Note how highest value corresponding to 0x7 is the lowest
+ * current, this is per the datasheet.
+ */
+enum rk817_chg_cur {
+	CHG_1A,
+	CHG_1_5A,
+	CHG_2A,
+	CHG_2_5A,
+	CHG_2_75A,
+	CHG_3A,
+	CHG_3_5A,
+	CHG_0_5A,
+};
+
+struct rk817_charger {
+	struct device *dev;
+	struct rk808 *rk808;
+
+	struct power_supply *bat_ps;
+	struct power_supply_battery_info bat_info;
+
+	struct power_supply *chg_ps;
+	bool plugged_in;
+
+	uint32_t voltage_k;
+	uint32_t voltage_b;
+
+	/* dsoc seems to be difference between full charge and actual charge in
+	 * BSP stored as a percentage, to the thousandth.
+	 */
+	int dsoc;
+
+	/* Implementation specific properties from device tree */
+	int res_div;
+	int sleep_enter_current;
+	int sleep_filter_current;
+};
+
+/* ADC coefficients extracted from BSP kernel */
+#define ADC_TO_CURRENT(adc_value, res_div)	\
+	(adc_value * 172 / res_div)
+
+#define CURRENT_TO_ADC(current, samp_res)	\
+	(current * samp_res / 172)
+
+#define CHARGE_TO_ADC(capacity, res_div)	\
+	(capacity * res_div * 3600 / 172 * 1000)
+
+#define ADC_TO_CHARGE_UAH(adc_value, res_div)	\
+	(adc_value / 3600 * 172 / res_div)
+
+#define ADC_TO_CAPACITY(adc_value, res_div)	\
+	(adc_value / 1000 * 172 / 3600 / res_div)
+
+static u8 rk817_chg_cur_to_reg(u32 chg_cur_ma)
+{
+	if (chg_cur_ma < 500)
+		return -EINVAL;
+	else if (chg_cur_ma < 1000)
+		return CHG_0_5A;
+	else if (chg_cur_ma < 1500)
+		return CHG_1A;
+	else if (chg_cur_ma < 2000)
+		return CHG_1_5A;
+	else if (chg_cur_ma < 2500)
+		return CHG_2A;
+	else if (chg_cur_ma < 2750)
+		return CHG_2_5A;
+	else if (chg_cur_ma < 3000)
+		return CHG_2_75A;
+	else if (chg_cur_ma < 3500)
+		return CHG_3A;
+	else
+		return CHG_3_5A;
+}
+
+static int rk817_chg_cur_from_reg(u8 reg)
+{
+	switch (reg) {
+	case CHG_0_5A:
+		return 500000;
+	case CHG_1A:
+		return 1000000;
+	case CHG_1_5A:
+		return 1500000;
+	case CHG_2A:
+		return 2000000;
+	case CHG_2_5A:
+		return 2500000;
+	case CHG_2_75A:
+		return 2750000;
+	case CHG_3A:
+		return 3000000;
+	case CHG_3_5A:
+		return 3500000;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int rk817_get_reg_hl(struct rk817_charger *charger, int regH, int regL)
+{
+	int tmp, ret;
+	uint32_t out;
+	struct rk808 *rk808 = charger->rk808;
+
+	ret = regmap_read(rk808->regmap, regL, &tmp);
+	if (ret)
+		return ret;
+	out |= tmp;
+
+	ret = regmap_read(rk808->regmap, regH, &tmp);
+	if (ret)
+		return ret;
+	out |= tmp << 8;
+
+	return out;
+}
+
+static void rk817_write_reg_hl(struct rk817_charger *charger, int regH,
+			       int regL, int val)
+{
+	uint8_t tmp;
+	struct rk808 *rk808 = charger->rk808;
+
+	tmp = val & 0xff;
+	regmap_write(rk808->regmap, regL, tmp);
+	tmp = (val >> 8) & 0xff;
+	regmap_write(rk808->regmap, regH, tmp);
+}
+
+static void rk817_bat_calib_vol(struct rk817_charger *charger)
+{
+	uint32_t vcalib0 = 0;
+	uint32_t vcalib1 = 0;
+
+	/* calibrate voltage */
+	vcalib0 = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_VCALIB0_H,
+				   RK817_GAS_GAUGE_VCALIB0_L);
+	vcalib1 = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_VCALIB1_H,
+				   RK817_GAS_GAUGE_VCALIB1_L);
+
+	/* values were taken from BSP kernel */
+	charger->voltage_k = (4025 - 2300) * 1000 /
+			     ((vcalib1 - vcalib0) ? (vcalib1 - vcalib0) : 1);
+	charger->voltage_b = 4025 - (charger->voltage_k * vcalib1) / 1000;
+}
+
+static void rk817_bat_calib_cur(struct rk817_charger *charger)
+{
+	int ioffset = 0;
+	/* calibrate current */
+	ioffset = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_IOFFSET_H,
+				   RK817_GAS_GAUGE_IOFFSET_L);
+	rk817_write_reg_hl(charger, RK817_GAS_GAUGE_CAL_OFFSET_H,
+			   RK817_GAS_GAUGE_CAL_OFFSET_L, ioffset);
+}
+
+static int rk817_bat_calib_cap(struct rk817_charger *charger)
+{
+	struct rk808 *rk808 = charger->rk808;
+	struct power_supply_battery_info *info = &charger->bat_info;
+	int reg, tmp, charge_now, charge_now_adc, dsoc_value;
+	u8 bulk_reg[4];
+
+	/* Calibrate the capacity on a fully charged battery */
+
+	regmap_read(rk808->regmap, RK817_PMIC_CHRG_STS, &reg);
+	tmp = (reg >> 4) & 0x07;
+	if (tmp == CHARGE_FINISH) {
+		regmap_bulk_read(rk808->regmap, RK817_GAS_GAUGE_Q_PRES_H3,
+				 bulk_reg, 4);
+		charge_now_adc = (bulk_reg[0] << 24) | (bulk_reg[1] << 16) |
+				 (bulk_reg[2] << 8) | bulk_reg[3];
+		if (charge_now_adc < 0)
+			charge_now_adc = 0;
+		charge_now = ADC_TO_CHARGE_UAH(charge_now_adc, charger->res_div);
+		dsoc_value = ((charge_now * 100) /
+			      (info->charge_full_design_uah / 1000));
+		if (dsoc_value > 100000)
+			charger->dsoc = 100000;
+		if (dsoc_value != charger->dsoc) {
+			charger->dsoc = dsoc_value;
+			bulk_reg[2] = (dsoc_value >> 16) & 0xff;
+			bulk_reg[1] = (dsoc_value >> 8) & 0xff;
+			bulk_reg[0] = dsoc_value & 0xff;
+			regmap_bulk_write(rk808->regmap,
+					  RK817_GAS_GAUGE_BAT_R1, bulk_reg, 3);
+		}
+	}
+
+	return 0;
+
+}
+
+static int rk817_bat_get_prop(struct power_supply *ps,
+		enum power_supply_property prop,
+		union power_supply_propval *val)
+{
+	struct rk817_charger *charger = power_supply_get_drvdata(ps);
+	uint32_t tmp = 0;
+	/* Registers for current is a signed 16bit int */
+	short int cur = 0;
+	/* Registers for capacity-now is a signed 32bit int */
+	int32_t charge_now = 0;
+	int ret = 0;
+	int reg = 0;
+	u8 bulk_reg[4];
+	struct rk808 *rk808 = charger->rk808;
+
+	/* Recalibrate voltage and current readings if we need to BSP does both
+	 * on CUR_CALIB_UPD, ignoring VOL_CALIB_UPD. Curiously enough, both
+	 * documentation and the BSP show that you perform an update if bit 7
+	 * is 1, but you clear the status by writing a 1 to bit 7.
+	 */
+	regmap_read(rk808->regmap, RK817_GAS_GAUGE_ADC_CONFIG1, &reg);
+	tmp = (reg >> 7) & 0x01;
+	if (tmp) {
+		rk817_bat_calib_cur(charger);
+		rk817_bat_calib_vol(charger);
+		regmap_write_bits(rk808->regmap, RK817_GAS_GAUGE_ADC_CONFIG1,
+				   RK817_CUR_CALIB_UPD, (1 << 7));
+	}
+
+	rk817_bat_calib_cap(charger);
+
+	switch (prop) {
+	case POWER_SUPPLY_PROP_PRESENT:
+		regmap_read(rk808->regmap, RK817_PMIC_CHRG_STS, &reg);
+		val->intval = (reg >> 7);
+		break;
+	case POWER_SUPPLY_PROP_STATUS:
+		if (!charger->plugged_in) {
+			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+			break;
+		}
+		ret = regmap_read(rk808->regmap, RK817_PMIC_CHRG_STS, &reg);
+		if (ret)
+			return ret;
+		tmp = (reg >> 4) & 0x07;
+		switch (tmp) {
+		case CHRG_OFF:
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+			break;
+		/* Dead charge is documented, but not explained. I never
+		 * observed it but assume it's a pre-charge for a dead
+		 * battery.
+		 */
+		case DEAD_CHRG:
+		case TRICKLE_CHRG:
+		case CC_OR_CV_CHRG:
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+			break;
+		case CHARGE_FINISH:
+			val->intval = POWER_SUPPLY_STATUS_FULL;
+			break;
+		default:
+			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+			return -EINVAL;
+
+		}
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_TYPE:
+		ret = regmap_read(rk808->regmap, RK817_PMIC_CHRG_STS, &reg);
+		if (ret)
+			return ret;
+		tmp = (reg >> 4) & 0x07;
+		switch (tmp) {
+		case CHRG_OFF:
+		case CHARGE_FINISH:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
+			break;
+		case TRICKLE_CHRG:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
+			break;
+		case DEAD_CHRG:
+		case CC_OR_CV_CHRG:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_STANDARD;
+			break;
+		default:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_UNKNOWN;
+			break;
+		}
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL:
+		val->intval = ((charger->bat_info.charge_full_design_uah /
+			       1000) * charger->dsoc) / 100;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+		val->intval = charger->bat_info.charge_full_design_uah;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN:
+		val->intval = 0;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_NOW:
+		regmap_bulk_read(rk808->regmap, RK817_GAS_GAUGE_Q_PRES_H3,
+				 bulk_reg, 4);
+		charge_now = (bulk_reg[0] << 24) | (bulk_reg[1] << 16) |
+			     (bulk_reg[2] << 8) | bulk_reg[3];
+		if (charge_now < 0)
+			charge_now = 0;
+		val->intval = ADC_TO_CHARGE_UAH(charge_now, charger->res_div);
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		val->intval = charger->bat_info.voltage_min_design_uv;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_BOOT:
+		tmp = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_PWRON_VOL_H,
+				       RK817_GAS_GAUGE_PWRON_VOL_L);
+		val->intval = (1000 * (((charger->voltage_k * tmp) / 1000) +
+			       charger->voltage_b));
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+		tmp = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_BAT_VOL_H,
+				       RK817_GAS_GAUGE_BAT_VOL_L);
+		val->intval = (1000 * (((charger->voltage_k * tmp) / 1000) +
+			       charger->voltage_b));
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_OCV:
+		tmp = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_OCV_VOL_H,
+				       RK817_GAS_GAUGE_OCV_VOL_H);
+		val->intval = (1000 * (((charger->voltage_k * tmp) / 1000) +
+			       charger->voltage_b));
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_BOOT:
+		cur = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_PWRON_CUR_H,
+				       RK817_GAS_GAUGE_PWRON_CUR_H);
+		val->intval = ADC_TO_CURRENT(cur, charger->res_div);
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_AVG:
+		cur = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_BAT_CUR_H,
+				       RK817_GAS_GAUGE_BAT_CUR_L);
+		val->intval = ADC_TO_CURRENT(cur, charger->res_div);
+		break;
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		regmap_read(rk808->regmap, RK817_PMIC_CHRG_OUT, &tmp);
+		val->intval = rk817_chg_cur_from_reg(tmp & RK817_CHRG_CUR_SEL);
+		break;
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		regmap_read(rk808->regmap, RK817_PMIC_CHRG_OUT, &tmp);
+		val->intval = ((((tmp & RK817_CHRG_VOL_SEL) >> 4) * 50000) +
+			       4100000);
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		val->intval = charger->bat_info.voltage_max_design_uv;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int rk817_chg_get_prop(struct power_supply *ps,
+			      enum power_supply_property prop,
+			      union power_supply_propval *val)
+{
+	struct rk817_charger *charger = power_supply_get_drvdata(ps);
+	int vol, tmp = 0;
+
+	switch (prop) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = charger->plugged_in;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		/* max voltage from datasheet at 5.5v (default 5.0v) */
+		val->intval = 5500000;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		/* min voltage from datasheet at 3.8v (default 5.0v) */
+		val->intval = 3800000;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+		/* Note that on my example hardware (an Odroid Go Advance) the
+		 * voltage of the power connector is measured on the register
+		 * labelled USB in the datasheet; I don't know if this is how
+		 * it is designed or just a quirk of the implementation. I
+		 * believe this will also measure the voltage of the USB output
+		 * when in OTG mode, if that is the case we may need to change
+		 * this in the future to return 0 if the power supply status
+		 * is offline.
+		 */
+		tmp = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_USB_VOL_H,
+				       RK817_GAS_GAUGE_USB_VOL_L);
+		vol = ((charger->voltage_k * tmp / 1000 + charger->voltage_b) *
+		       60 / 46);
+		val->intval = vol * 1000;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+
+}
+
+static irqreturn_t rk817_plug_in_isr(int irq, void *cg)
+{
+	struct rk817_charger *charger;
+
+	charger = (struct rk817_charger *)cg;
+	charger->plugged_in = 1;
+	power_supply_changed(charger->chg_ps);
+	power_supply_changed(charger->bat_ps);
+	dev_dbg(charger->dev, "Power Cord Inserted\n");
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t rk817_plug_out_isr(int irq, void *cg)
+{
+	struct rk817_charger *charger;
+	struct rk808 *rk808;
+
+	charger = (struct rk817_charger *)cg;
+	rk808 = charger->rk808;
+	charger->plugged_in = 0;
+	power_supply_changed(charger->bat_ps);
+	power_supply_changed(charger->chg_ps);
+
+	/* For some reason the bits of RK817_PMIC_CHRG_IN reset whenever the
+	 * power cord is unplugged. This was not documented in the BSP kernel
+	 * or the datasheet and only discovered by trial and error. Set minimum
+	 * USB input voltage to 4.5v and enable USB voltage input limit.
+	 */
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN,
+			  RK817_USB_VLIM_SEL, (0x05 << 4));
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN, RK817_USB_VLIM_EN,
+			  (0x01 << 7));
+
+	/* Set average USB input current limit to 1.5A and enable USB current
+	 * input limit.
+	 */
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN,
+			  RK817_USB_ILIM_SEL, 0x03);
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN, RK817_USB_ILIM_EN,
+			  (0x01 << 3));
+
+	dev_dbg(charger->dev, "Power Cord Removed\n");
+
+	return IRQ_HANDLED;
+}
+
+static enum power_supply_property rk817_bat_props[] = {
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_CHARGE_TYPE,
+	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+	POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
+	POWER_SUPPLY_PROP_VOLTAGE_BOOT,
+	POWER_SUPPLY_PROP_VOLTAGE_AVG,
+	POWER_SUPPLY_PROP_VOLTAGE_OCV,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
+	POWER_SUPPLY_PROP_CURRENT_BOOT,
+	POWER_SUPPLY_PROP_CURRENT_AVG,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+};
+
+static enum power_supply_property rk817_chg_props[] = {
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_AVG,
+};
+
+static const struct power_supply_desc rk817_bat_desc = {
+	.name = "rk817-battery",
+	.type = POWER_SUPPLY_TYPE_BATTERY,
+	.properties = rk817_bat_props,
+	.num_properties = ARRAY_SIZE(rk817_bat_props),
+	.get_property = rk817_bat_get_prop,
+};
+
+/* Note that all known existing implementations use a "USB" port that is either
+ * a power only port (no data lines) or use barrel plug to USB cable. Setting
+ * to POWER_SUPPLY_TYPE_USB_DCP.
+ */
+static const struct power_supply_desc rk817_chg_desc = {
+	.name = "rk817-charger",
+	.type = POWER_SUPPLY_TYPE_USB_DCP,
+	.properties = rk817_chg_props,
+	.num_properties = ARRAY_SIZE(rk817_chg_props),
+	.get_property = rk817_chg_get_prop,
+};
+
+static int rk817_read_or_set_full_charge_on_boot(struct rk817_charger *charger)
+{
+	struct rk808 *rk808 = charger->rk808;
+	struct power_supply_battery_info *info = &charger->bat_info;
+	u8 reg[4];
+	u32 design_charge_mah = (info->charge_full_design_uah / 1000);
+	u32 boot_voltage, boot_capacity, boot_charge, tmp, full_charge_cap;
+	int ret;
+
+	/* Read DSOC value if pre-existing. If not, initialize at 100%.
+	 * Note endianness, also register says it's for resistance,
+	 * however BSP kernel treats this as an nvram field for the DSOC
+	 * as best I can tell. Doing the same for backwards compatibility.
+	 */
+	ret = regmap_bulk_read(rk808->regmap, RK817_GAS_GAUGE_BAT_R1, reg, 3);
+	if (ret < 0)
+		return ret;
+
+	charger->dsoc = (reg[2] << 16) | (reg[1] << 8) | (reg[0]);
+	/* If we have an invalid DSOC, write 100 (100000) as default. */
+	if (charger->dsoc < 1000 || charger->dsoc > 100000) {
+		regmap_write(rk808->regmap, RK817_GAS_GAUGE_BAT_R1, 0xa0);
+		regmap_write(rk808->regmap, RK817_GAS_GAUGE_BAT_R2, 0x86);
+		regmap_write(rk808->regmap, RK817_GAS_GAUGE_BAT_R3, 0x01);
+		charger->dsoc = 100000;
+	}
+
+	/* Register appears to be nvram that stores capacity in mAH. Note
+	 * endianness, keeping consistent with BSP kernel, however it looks
+	 * like we can use any arbitrary method to store value if we don't care
+	 * about compatibility. Additionally, it doesn't appear that this value
+	 * is used for anything, so realistically getting it and setting it is
+	 * to ensure backward compatibility with BSP and serves no purpose with
+	 * this driver, and I'm not sure if the BSP driver does anything with
+	 * this value either.
+	 */
+
+	ret = regmap_bulk_read(rk808->regmap, RK817_GAS_GAUGE_DATA3, reg, 3);
+	if (ret < 0)
+		return ret;
+
+	full_charge_cap = (reg[2] << 16) | (reg[1] << 8) | (reg[0]);
+
+	/* Sanity checking for values equal to zero or less than would be
+	 * practical for this device (BSP Kernel assumes 500mAH or less) for
+	 * practicality purposes.
+	 */
+	if (full_charge_cap < 500) {
+		reg[2] = (design_charge_mah >> 16) & 0xff;
+		reg[1] = (design_charge_mah >> 8) & 0xff;
+		reg[0] = design_charge_mah & 0xff;
+		ret = regmap_bulk_write(rk808->regmap, RK817_GAS_GAUGE_DATA3, reg, 3);
+		if (ret < 0)
+			return ret;
+		dev_info(charger->dev,
+			 "Invalid NVRAM Data for max charge, setting to design capacity %u uAH\n",
+			 design_charge_mah*1000);
+	}
+
+	/* Capture boot voltage and look up boot capacity from OCV tables. */
+
+	tmp = rk817_get_reg_hl(charger, RK817_GAS_GAUGE_PWRON_VOL_H,
+			       RK817_GAS_GAUGE_PWRON_VOL_L);
+	boot_voltage = (1000 * (((charger->voltage_k * tmp) / 1000) +
+			charger->voltage_b));
+	/* Since only implementation has no working thermistor, assume 20C for
+	 * OCV lookup.
+	 */
+	boot_capacity = power_supply_batinfo_ocv2cap(info, boot_voltage, 20);
+
+	/* Write boot charge to registers, estimate boot charge based on
+	 * capacity and max charge of battery.
+	 */
+	boot_charge = (boot_capacity * info->charge_full_design_uah) / 100;
+	tmp = CHARGE_TO_ADC((boot_charge / 1000), charger->res_div);
+	regmap_write(rk808->regmap, RK817_GAS_GAUGE_Q_INIT_H3,
+		     (tmp >> 24) & 0xFF);
+	regmap_write(rk808->regmap, RK817_GAS_GAUGE_Q_INIT_H2,
+		     (tmp >> 16) & 0xFF);
+	regmap_write(rk808->regmap, RK817_GAS_GAUGE_Q_INIT_L1,
+		     (tmp >> 8) & 0xFF);
+	regmap_write(rk808->regmap, RK817_GAS_GAUGE_Q_INIT_L0,
+		     tmp & 0xFF);
+
+	/* Set QMAX value to max design capacity. */
+	tmp = CHARGE_TO_ADC((info->charge_full_design_uah / 1000),
+			    charger->res_div);
+	reg[0] = (tmp >> 24) & 0xff;
+	reg[1] = (tmp >> 16) & 0xff;
+	reg[2] = (tmp >> 8) & 0xff;
+	reg[3] = tmp & 0xff;
+	ret = regmap_bulk_write(rk808->regmap, RK817_GAS_GAUGE_Q_MAX_H3,
+				reg, 4);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+
+}
+
+static int rk817_battery_init(struct rk817_charger *charger)
+{
+	struct rk808 *rk808 = charger->rk808;
+	struct power_supply_battery_info *info = &charger->bat_info;
+	u32 tmp, max_chg_vol_mv, max_chg_cur_ma;
+	u8 max_chg_vol_reg, chg_term_i_reg, max_chg_cur_reg;
+	int ret, chg_term_ma;
+
+	/* Get initial plug state */
+	regmap_read(rk808->regmap, RK817_SYS_STS, &tmp);
+	charger->plugged_in = (tmp & RK817_PLUG_IN_STS);
+
+	/* Turn on all ADC functions to measure battery, USB, and sys voltage,
+	 * as well as batt temp. Note only tested implementation so far does
+	 * not use a battery with a thermistor.
+	 */
+	regmap_write(rk808->regmap, RK817_GAS_GAUGE_ADC_CONFIG0, 0xfc);
+
+	/* Set relax mode voltage sampling interval and ADC offset calibration
+	 * interval to 8 minutes to mirror BSP kernel. Set voltage and current
+	 * modes to average to mirror BSP kernel.
+	 */
+	regmap_write(rk808->regmap, RK817_GAS_GAUGE_GG_CON, 0x04);
+
+	/* Write relax threshold, derived from sleep enter current. */
+	tmp = CURRENT_TO_ADC(charger->sleep_enter_current, charger->res_div);
+	rk817_write_reg_hl(charger, RK817_GAS_GAUGE_RELAX_THRE_H,
+			   RK817_GAS_GAUGE_RELAX_THRE_L, tmp);
+
+	/* Write sleep sample current, derived from sleep filter current. */
+	tmp = CURRENT_TO_ADC(charger->sleep_filter_current, charger->res_div);
+	rk817_write_reg_hl(charger, RK817_GAS_GAUGE_SLEEP_CON_SAMP_CUR_H,
+			   RK817_GAS_GAUGE_SLEEP_CON_SAMP_CUR_L, tmp);
+
+	/* Restart battery relax voltage */
+	regmap_write_bits(rk808->regmap, RK817_GAS_GAUGE_GG_STS,
+			  RK817_RELAX_VOL_UPD, (0x0 << 2));
+
+	/* Set OCV Threshold Voltage to 127.5mV. This was hard coded like this
+	 * in the BSP.
+	 */
+	regmap_write(rk808->regmap, RK817_GAS_GAUGE_OCV_THRE_VOL, 0xff);
+
+	/* Set maximum charging voltage to battery max voltage. Trying to be
+	 * incredibly safe with these value, as setting them wrong could
+	 * overcharge the battery, which would be very bad.
+	 */
+	max_chg_vol_mv = info->constant_charge_voltage_max_uv / 1000;
+	max_chg_cur_ma = info->constant_charge_current_max_ua / 1000;
+
+	if (max_chg_vol_mv < 4100) {
+		dev_emerg(charger->dev,
+			  "Danger, invalid max charger voltage! Value %u unsupported\n",
+			  max_chg_vol_mv * 1000);
+		return -EINVAL;
+	}
+	if (max_chg_vol_mv > 4450) {
+		dev_info(charger->dev,
+			 "Setting max charge voltage to 4450000uv\n");
+		max_chg_vol_mv = 4450;
+	}
+
+	if (max_chg_cur_ma < 500) {
+		dev_emerg(charger->dev,
+			  "Danger, invalid max charger current! Value %u unsupported\n",
+			  max_chg_cur_ma * 1000);
+		return -EINVAL;
+	}
+	if (max_chg_cur_ma > 3500)
+		dev_info(charger->dev,
+			 "Setting max charge current to 3500000ua\n");
+
+	/* Now that the values are sanity checked, if we subtract 4100 from the
+	 * max voltage and divide by 50, we conviently get the exact value for
+	 * the registers, which are 4.1v, 4.15v, 4.2v, 4.25v, 4.3v, 4.35v,
+	 * 4.4v, and 4.45v; these correspond to values 0x00 through 0x07.
+	 */
+	max_chg_vol_reg = (max_chg_vol_mv - 4100) / 50;
+
+	max_chg_cur_reg = rk817_chg_cur_to_reg(max_chg_cur_ma);
+
+	if (max_chg_vol_reg < 0 || max_chg_vol_reg > 7) {
+		dev_emerg(charger->dev,
+			  "Danger, invalid max charger voltage! Value %u unsupported\n",
+			  max_chg_vol_mv * 1000);
+		return -EINVAL;
+	}
+	if (max_chg_cur_reg < 0 || max_chg_cur_reg > 7) {
+		dev_emerg(charger->dev,
+			  "Danger, invalid max charger voltage! Value %u unsupported\n",
+			  max_chg_cur_ma * 1000);
+		return -EINVAL;
+	}
+
+	/* Write the values to the registers, and deliver an emergency warning
+	 * in the event they are not written correctly.
+	 */
+	ret = regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_OUT,
+				RK817_CHRG_VOL_SEL, (max_chg_vol_reg << 4));
+	if (ret) {
+		dev_emerg(charger->dev,
+			  "Danger, unable to set max charger voltage: %u\n",
+			  ret);
+	}
+
+	ret = regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_OUT,
+				RK817_CHRG_CUR_SEL, max_chg_cur_reg);
+	if (ret) {
+		dev_emerg(charger->dev,
+			  "Danger, unable to set max charger current: %u\n",
+			  ret);
+	}
+
+	/* Set charge finishing mode to analog */
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_TERM,
+			  RK817_CHRG_TERM_ANA_DIG, (0x0 << 2));
+
+	/* Set charge finish current, warn if value not in range and keep
+	 * default.
+	 */
+	chg_term_ma = info->charge_term_current_ua / 1000;
+	if (chg_term_ma < 150 || chg_term_ma > 400) {
+		dev_warn(charger->dev,
+			 "Invalid charge termination value %u, keeping default\n",
+			 chg_term_ma * 1000);
+		chg_term_ma = 200;
+	}
+
+	/* Values of 150ma, 200ma, 300ma, and 400ma correspond to 00, 01, 10,
+	 * and 11.
+	 */
+	chg_term_i_reg = (chg_term_ma - 100) / 100;
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_TERM,
+			  RK817_CHRG_TERM_ANA_SEL, chg_term_i_reg);
+
+	ret = rk817_read_or_set_full_charge_on_boot(charger);
+	if (ret < 0)
+		return ret;
+
+	/* Set minimum USB input voltage to 4.5v and enable USB voltage input
+	 * limit.
+	 */
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN,
+			  RK817_USB_VLIM_SEL, (0x05 << 4));
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN, RK817_USB_VLIM_EN,
+			  (0x01 << 7));
+
+	/* Set average USB input current limit to 1.5A and enable USB current
+	 * input limit.
+	 */
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN,
+			  RK817_USB_ILIM_SEL, 0x03);
+	regmap_write_bits(rk808->regmap, RK817_PMIC_CHRG_IN, RK817_USB_ILIM_EN,
+			  (0x01 << 3));
+
+	return 0;
+
+}
+
+static int rk817_charger_probe(struct platform_device *pdev)
+{
+	struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
+	struct rk817_charger *charger;
+	struct device_node *node;
+	struct power_supply_battery_info *info;
+	struct device *dev = &pdev->dev;
+	struct power_supply_config pscfg = {};
+	int plugin_irq, plugout_irq;
+	int of_value;
+	int ret;
+
+	node = of_get_child_by_name(dev->parent->of_node, "battery");
+	if (!node)
+		return -ENODEV;
+
+	charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
+	if (!charger)
+		return -ENOMEM;
+
+	charger->rk808 = rk808;
+
+	charger->dev = &pdev->dev;
+	platform_set_drvdata(pdev, charger);
+
+	rk817_bat_calib_vol(charger);
+
+	pscfg.drv_data = charger;
+	pscfg.of_node = node;
+
+	/* Get sample resistor value. Note only values of 10000 or 20000
+	 * microohms are allowed. Schematic for my test implementation (an
+	 * Odroid Go Advance) shows a 10 milliohm resistor for reference.
+	 */
+	ret = of_property_read_u32(node, "rockchip,resistor-sense", &of_value);
+	if (ret < 0) {
+		dev_err(dev, "Error reading sample resistor value: %i\n", ret);
+		return ret;
+	}
+	/* Store as a 1 or a 2, since all we really use the value for is as a
+	 * divisor in some calculations.
+	 */
+	charger->res_div = (of_value == 20000) ? 2 : 1;
+
+	/* Get sleep enter current value. Not sure what this value is for
+	 * other than to help calibrate the relax threshold.
+	 */
+	ret = of_property_read_u32(node, "rockchip,sleep-enter-current",
+				   &of_value);
+	if (ret < 0) {
+		dev_err(dev, "Error reading sleep enter current value: %i\n",
+			ret);
+		return ret;
+	}
+	charger->sleep_enter_current = of_value;
+
+	/* Get sleep filter current value */
+	ret = of_property_read_u32(node, "rockchip,sleep-filter-current",
+				   &of_value);
+	if (ret < 0) {
+		dev_err(dev, "Error reading sleep filter current value: %i\n",
+			ret);
+		return ret;
+	}
+	charger->sleep_filter_current = of_value;
+
+	charger->bat_ps = devm_power_supply_register(&pdev->dev,
+						     &rk817_bat_desc, &pscfg);
+
+	charger->chg_ps = devm_power_supply_register(&pdev->dev,
+						     &rk817_chg_desc, &pscfg);
+
+	ret = power_supply_get_battery_info(charger->bat_ps,
+					    &charger->bat_info);
+	if (ret) {
+		dev_err(dev, "Unable to get battery info: %d\n", ret);
+		return ret;
+	}
+
+	info = &charger->bat_info;
+	if ((!info->charge_full_design_uah) ||
+	    (!info->voltage_min_design_uv) ||
+	    (!info->voltage_max_design_uv) ||
+	    (!info->constant_charge_voltage_max_uv) ||
+	    (!info->constant_charge_current_max_ua) ||
+	    (!info->charge_term_current_ua) ||
+	    (!info->ocv_table)) {
+		dev_err(dev, "Required battery information missing.\n");
+		return -EINVAL;
+	}
+
+	/* Has to run after power_supply_get_battery_info as it depends on some
+	 * values discovered from that routine.
+	 */
+	ret = rk817_battery_init(charger);
+	if (ret)
+		return ret;
+
+	plugin_irq = platform_get_irq(pdev, 0);
+	if (plugin_irq < 0)
+		return plugin_irq;
+
+	plugout_irq = platform_get_irq(pdev, 1);
+	if (plugout_irq < 0)
+		return plugout_irq;
+
+	ret = devm_request_threaded_irq(charger->dev, plugin_irq, NULL,
+					rk817_plug_in_isr,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					"rk817_plug_in", charger);
+	if (ret) {
+		dev_err(&pdev->dev, "plug_in_irq request failed!\n");
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(charger->dev, plugout_irq, NULL,
+					rk817_plug_out_isr,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					"rk817_plug_out", charger);
+	if (ret) {
+		dev_err(&pdev->dev, "plug_out_irq request failed!\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+
+static struct platform_driver rk817_charger_driver = {
+	.probe    = rk817_charger_probe,
+	.driver   = {
+		.name  = "rk817-charger",
+	},
+};
+module_platform_driver(rk817_charger_driver);
+
+MODULE_DESCRIPTION("Battery power supply driver for RK817 PMIC");
+MODULE_AUTHOR("Maya Matuszczyk <maccraft123mc@gmail.com>");
+MODULE_LICENSE("GPL");
-- 
2.25.1