drivers/rtc/rtc-ab-eoz9.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Real Time Clock driver for AB-RTCMC-32.768kHz-EOZ9 chip.
  * Copyright (C) 2019 Orolia
  *
  */

 #include <linux/module.h>
 #include <linux/rtc.h>
 #include <linux/i2c.h>
 #include <linux/bcd.h>
 #include <linux/of.h>
 #include <linux/regmap.h>
 #include <linux/bitfield.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>

 #define ABEOZ9_REG_CTRL1		0x00
 #define ABEOZ9_REG_CTRL1_MASK		GENMASK(7, 0)
 #define ABEOZ9_REG_CTRL1_WE		BIT(0)
 #define ABEOZ9_REG_CTRL1_TE		BIT(1)
 #define ABEOZ9_REG_CTRL1_TAR		BIT(2)
 #define ABEOZ9_REG_CTRL1_EERE		BIT(3)
 #define ABEOZ9_REG_CTRL1_SRON		BIT(4)
 #define ABEOZ9_REG_CTRL1_TD0		BIT(5)
 #define ABEOZ9_REG_CTRL1_TD1		BIT(6)
 #define ABEOZ9_REG_CTRL1_CLKINT		BIT(7)

 #define ABEOZ9_REG_CTRL_INT		0x01
 #define ABEOZ9_REG_CTRL_INT_AIE		BIT(0)
 #define ABEOZ9_REG_CTRL_INT_TIE		BIT(1)
 #define ABEOZ9_REG_CTRL_INT_V1IE	BIT(2)
 #define ABEOZ9_REG_CTRL_INT_V2IE	BIT(3)
 #define ABEOZ9_REG_CTRL_INT_SRIE	BIT(4)

 #define ABEOZ9_REG_CTRL_INT_FLAG	0x02
 #define ABEOZ9_REG_CTRL_INT_FLAG_AF	BIT(0)
 #define ABEOZ9_REG_CTRL_INT_FLAG_TF	BIT(1)
 #define ABEOZ9_REG_CTRL_INT_FLAG_V1IF	BIT(2)
 #define ABEOZ9_REG_CTRL_INT_FLAG_V2IF	BIT(3)
 #define ABEOZ9_REG_CTRL_INT_FLAG_SRF	BIT(4)

 #define ABEOZ9_REG_CTRL_STATUS		0x03
 #define ABEOZ9_REG_CTRL_STATUS_V1F	BIT(2)
 #define ABEOZ9_REG_CTRL_STATUS_V2F	BIT(3)
 #define ABEOZ9_REG_CTRL_STATUS_SR	BIT(4)
 #define ABEOZ9_REG_CTRL_STATUS_PON	BIT(5)
 #define ABEOZ9_REG_CTRL_STATUS_EEBUSY	BIT(7)

 #define ABEOZ9_REG_SEC			0x08
 #define ABEOZ9_REG_MIN			0x09
 #define ABEOZ9_REG_HOURS		0x0A
 #define ABEOZ9_HOURS_PM			BIT(6)
 #define ABEOZ9_REG_DAYS			0x0B
 #define ABEOZ9_REG_WEEKDAYS		0x0C
 #define ABEOZ9_REG_MONTHS		0x0D
 #define ABEOZ9_REG_YEARS		0x0E

 #define ABEOZ9_SEC_LEN			7

 #define ABEOZ9_REG_ALARM_SEC		0x10
 #define ABEOZ9_BIT_ALARM_SEC		GENMASK(6, 0)
 #define ABEOZ9_REG_ALARM_MIN		0x11
 #define ABEOZ9_BIT_ALARM_MIN		GENMASK(6, 0)
 #define ABEOZ9_REG_ALARM_HOURS		0x12
 #define ABEOZ9_BIT_ALARM_HOURS_PM	BIT(5)
 #define ABEOZ9_BIT_ALARM_HOURS		GENMASK(4, 0)
 #define ABEOZ9_REG_ALARM_DAYS		0x13
 #define ABEOZ9_BIT_ALARM_DAYS		GENMASK(5, 0)
 #define ABEOZ9_REG_ALARM_WEEKDAYS	0x14
 #define ABEOZ9_BIT_ALARM_WEEKDAYS	GENMASK(2, 0)
 #define ABEOZ9_REG_ALARM_MONTHS		0x15
 #define ABEOZ9_BIT_ALARM_MONTHS		GENMASK(4, 0)
 #define ABEOZ9_REG_ALARM_YEARS		0x16

 #define ABEOZ9_ALARM_LEN		7
 #define ABEOZ9_BIT_ALARM_AE		BIT(7)

 #define ABEOZ9_REG_REG_TEMP		0x20
 #define ABEOZ953_TEMP_MAX		120
 #define ABEOZ953_TEMP_MIN		-60

 #define ABEOZ9_REG_EEPROM		0x30
 #define ABEOZ9_REG_EEPROM_MASK		GENMASK(8, 0)
 #define ABEOZ9_REG_EEPROM_THP		BIT(0)
 #define ABEOZ9_REG_EEPROM_THE		BIT(1)
 #define ABEOZ9_REG_EEPROM_FD0		BIT(2)
 #define ABEOZ9_REG_EEPROM_FD1		BIT(3)
 #define ABEOZ9_REG_EEPROM_R1K		BIT(4)
 #define ABEOZ9_REG_EEPROM_R5K		BIT(5)
 #define ABEOZ9_REG_EEPROM_R20K		BIT(6)
 #define ABEOZ9_REG_EEPROM_R80K		BIT(7)

 struct abeoz9_rtc_data {
 	struct rtc_device *rtc;
 	struct regmap *regmap;
 	struct device *hwmon_dev;
 };

 static int abeoz9_check_validity(struct device *dev)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
 	int ret;
 	int val;

 	ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
 	if (ret < 0) {
 		dev_err(dev,
 			"unable to get CTRL_STATUS register (%d)\n", ret);
 		return ret;
 	}

 	if (val & ABEOZ9_REG_CTRL_STATUS_PON) {
 		dev_warn(dev, "power-on reset detected, date is invalid\n");
 		return -EINVAL;
 	}

 	if (val & ABEOZ9_REG_CTRL_STATUS_V1F) {
 		dev_warn(dev,
 			 "voltage drops below VLOW1 threshold, date is invalid\n");
 		return -EINVAL;
 	}

 	if ((val & ABEOZ9_REG_CTRL_STATUS_V2F)) {
 		dev_warn(dev,
 			 "voltage drops below VLOW2 threshold, date is invalid\n");
 		return -EINVAL;
 	}

 	return 0;
 }

 static int abeoz9_reset_validity(struct regmap *regmap)
 {
 	return regmap_update_bits(regmap, ABEOZ9_REG_CTRL_STATUS,
 				  ABEOZ9_REG_CTRL_STATUS_V1F |
 				  ABEOZ9_REG_CTRL_STATUS_V2F |
 				  ABEOZ9_REG_CTRL_STATUS_PON,
 				  0);
 }

 static int abeoz9_rtc_get_time(struct device *dev, struct rtc_time *tm)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	u8 regs[ABEOZ9_SEC_LEN];
 	int ret;

 	ret = abeoz9_check_validity(dev);
 	if (ret)
 		return ret;

 	ret = regmap_bulk_read(data->regmap, ABEOZ9_REG_SEC,
 			       regs,
 			       sizeof(regs));
 	if (ret) {
 		dev_err(dev, "reading RTC time failed (%d)\n", ret);
 		return ret;
 	}

 	tm->tm_sec = bcd2bin(regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] & 0x7F);
 	tm->tm_min = bcd2bin(regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] & 0x7F);

 	if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM) {
 		tm->tm_hour =
 			bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & 0x1f);
 		if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM)
 			tm->tm_hour += 12;
 	} else {
 		tm->tm_hour = bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC]);
 	}

 	tm->tm_mday = bcd2bin(regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC]);
 	tm->tm_wday = bcd2bin(regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC]);
 	tm->tm_mon  = bcd2bin(regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC]) - 1;
 	tm->tm_year = bcd2bin(regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC]) + 100;

 	return ret;
 }

 static int abeoz9_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
 	u8 regs[ABEOZ9_SEC_LEN];
 	int ret;

 	regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_sec);
 	regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_min);
 	regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_hour);
 	regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mday);
 	regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_wday);
 	regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mon + 1);
 	regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_year - 100);

 	ret = regmap_bulk_write(data->regmap, ABEOZ9_REG_SEC,
 				regs,
 				sizeof(regs));

 	if (ret) {
 		dev_err(dev, "set RTC time failed (%d)\n", ret);
 		return ret;
 	}

 	return abeoz9_reset_validity(regmap);
 }

 static int abeoz9_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
 	u8 regs[ABEOZ9_ALARM_LEN];
 	u8 val[2];
 	int ret;

 	ret = abeoz9_check_validity(dev);
 	if (ret)
 		return ret;

 	ret = regmap_bulk_read(regmap, ABEOZ9_REG_CTRL_INT, val, sizeof(val));
 	if (ret)
 		return ret;

 	alarm->enabled = val[0] & ABEOZ9_REG_CTRL_INT_AIE;
 	alarm->pending = val[1] & ABEOZ9_REG_CTRL_INT_FLAG_AF;

 	ret = regmap_bulk_read(regmap, ABEOZ9_REG_ALARM_SEC, regs, sizeof(regs));
 	if (ret)
 		return ret;

 	alarm->time.tm_sec = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_SEC, regs[0]));
 	alarm->time.tm_min = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_MIN, regs[1]));
 	alarm->time.tm_hour = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_HOURS, regs[2]));
 	if (FIELD_GET(ABEOZ9_BIT_ALARM_HOURS_PM, regs[2]))
 		alarm->time.tm_hour += 12;

 	alarm->time.tm_mday = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_DAYS, regs[3]));

 	return 0;
 }

 static int abeoz9_rtc_alarm_irq_enable(struct device *dev, u32 enable)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);

 	return regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT,
 				  ABEOZ9_REG_CTRL_INT_AIE,
 				  FIELD_PREP(ABEOZ9_REG_CTRL_INT_AIE, enable));
 }

 static int abeoz9_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	u8 regs[ABEOZ9_ALARM_LEN] = {0};
 	int ret;

 	ret = regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG,
 				 ABEOZ9_REG_CTRL_INT_FLAG_AF, 0);
 	if (ret)
 		return ret;

 	regs[0] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_SEC,
 						   bin2bcd(alarm->time.tm_sec));
 	regs[1] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_MIN,
 						   bin2bcd(alarm->time.tm_min));
 	regs[2] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_HOURS,
 						   bin2bcd(alarm->time.tm_hour));
 	regs[3] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_DAYS,
 						   bin2bcd(alarm->time.tm_mday));

 	ret = regmap_bulk_write(data->regmap, ABEOZ9_REG_ALARM_SEC, regs,
 				sizeof(regs));
 	if (ret)
 		return ret;

 	return abeoz9_rtc_alarm_irq_enable(dev, alarm->enabled);
 }

 static irqreturn_t abeoz9_rtc_irq(int irq, void *dev)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	unsigned int val;
 	int ret;

 	ret = regmap_read(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG, &val);
 	if (ret)
 		return IRQ_NONE;

 	if (!FIELD_GET(ABEOZ9_REG_CTRL_INT_FLAG_AF, val))
 		return IRQ_NONE;

 	regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG,
 			   ABEOZ9_REG_CTRL_INT_FLAG_AF, 0);

 	rtc_update_irq(data->rtc, 1, RTC_IRQF | RTC_AF);

 	return IRQ_HANDLED;
 }

 static int abeoz9_trickle_parse_dt(struct device_node *node)
 {
 	u32 ohms = 0;

 	if (of_property_read_u32(node, "trickle-resistor-ohms", &ohms))
 		return 0;

 	switch (ohms) {
 	case 1000:
 		return ABEOZ9_REG_EEPROM_R1K;
 	case 5000:
 		return ABEOZ9_REG_EEPROM_R5K;
 	case 20000:
 		return ABEOZ9_REG_EEPROM_R20K;
 	case 80000:
 		return ABEOZ9_REG_EEPROM_R80K;
 	default:
 		return 0;
 	}
 }

 static int abeoz9_rtc_setup(struct device *dev, struct device_node *node)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
 	int ret;

 	/* Enable Self Recovery, Clock for Watch and EEPROM refresh functions */
 	ret = regmap_update_bits(regmap, ABEOZ9_REG_CTRL1,
 				 ABEOZ9_REG_CTRL1_MASK,
 				 ABEOZ9_REG_CTRL1_WE |
 				 ABEOZ9_REG_CTRL1_EERE |
 				 ABEOZ9_REG_CTRL1_SRON);
 	if (ret < 0) {
 		dev_err(dev, "unable to set CTRL_1 register (%d)\n", ret);
 		return ret;
 	}

 	ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT, 0);
 	if (ret < 0) {
 		dev_err(dev,
 			"unable to set control CTRL_INT register (%d)\n",
 			ret);
 		return ret;
 	}

 	ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT_FLAG, 0);
 	if (ret < 0) {
 		dev_err(dev,
 			"unable to set control CTRL_INT_FLAG register (%d)\n",
 			ret);
 		return ret;
 	}

 	ret = abeoz9_trickle_parse_dt(node);

 	/* Enable built-in termometer */
 	ret |= ABEOZ9_REG_EEPROM_THE;

 	ret = regmap_update_bits(regmap, ABEOZ9_REG_EEPROM,
 				 ABEOZ9_REG_EEPROM_MASK,
 				 ret);
 	if (ret < 0) {
 		dev_err(dev, "unable to set EEPROM register (%d)\n", ret);
 		return ret;
 	}

 	return ret;
 }

 static const struct rtc_class_ops rtc_ops = {
 	.read_time = abeoz9_rtc_get_time,
 	.set_time = abeoz9_rtc_set_time,
 	.read_alarm = abeoz9_rtc_read_alarm,
 	.set_alarm = abeoz9_rtc_set_alarm,
 	.alarm_irq_enable = abeoz9_rtc_alarm_irq_enable,
 };

 static const struct regmap_config abeoz9_rtc_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = 0x3f,
 };

 #if IS_REACHABLE(CONFIG_HWMON)

 static int abeoz9z3_temp_read(struct device *dev,
 			      enum hwmon_sensor_types type,
 			      u32 attr, int channel, long *temp)
 {
 	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
 	int ret;
 	unsigned int val;

 	ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
 	if (ret < 0)
 		return ret;

 	if ((val & ABEOZ9_REG_CTRL_STATUS_V1F) ||
 	    (val & ABEOZ9_REG_CTRL_STATUS_V2F)) {
 		dev_err(dev,
 			"thermometer might be disabled due to low voltage\n");
 		return -EINVAL;
 	}

 	switch (attr) {
 	case hwmon_temp_input:
 		ret = regmap_read(regmap, ABEOZ9_REG_REG_TEMP, &val);
 		if (ret < 0)
 			return ret;
 		*temp = 1000 * (val + ABEOZ953_TEMP_MIN);
 		return 0;
 	case hwmon_temp_max:
 		*temp = 1000 * ABEOZ953_TEMP_MAX;
 		return 0;
 	case hwmon_temp_min:
 		*temp = 1000 * ABEOZ953_TEMP_MIN;
 		return 0;
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static umode_t abeoz9_is_visible(const void *data,
 				 enum hwmon_sensor_types type,
 				 u32 attr, int channel)
 {
 	switch (attr) {
 	case hwmon_temp_input:
 	case hwmon_temp_max:
 	case hwmon_temp_min:
 		return 0444;
 	default:
 		return 0;
 	}
 }

 static const u32 abeoz9_chip_config[] = {
 	HWMON_C_REGISTER_TZ,
 	0
 };

 static const struct hwmon_channel_info abeoz9_chip = {
 	.type = hwmon_chip,
 	.config = abeoz9_chip_config,
 };

 static const u32 abeoz9_temp_config[] = {
 	HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN,
 	0
 };

 static const struct hwmon_channel_info abeoz9_temp = {
 	.type = hwmon_temp,
 	.config = abeoz9_temp_config,
 };

 static const struct hwmon_channel_info * const abeoz9_info[] = {
 	&abeoz9_chip,
 	&abeoz9_temp,
 	NULL
 };

 static const struct hwmon_ops abeoz9_hwmon_ops = {
 	.is_visible = abeoz9_is_visible,
 	.read = abeoz9z3_temp_read,
 };

 static const struct hwmon_chip_info abeoz9_chip_info = {
 	.ops = &abeoz9_hwmon_ops,
 	.info = abeoz9_info,
 };

 static void abeoz9_hwmon_register(struct device *dev,
 				  struct abeoz9_rtc_data *data)
 {
 	data->hwmon_dev =
 		devm_hwmon_device_register_with_info(dev,
 						     "abeoz9",
 						     data,
 						     &abeoz9_chip_info,
 						     NULL);
 	if (IS_ERR(data->hwmon_dev)) {
 		dev_warn(dev, "unable to register hwmon device %ld\n",
 			 PTR_ERR(data->hwmon_dev));
 	}
 }

 #else

 static void abeoz9_hwmon_register(struct device *dev,
 				  struct abeoz9_rtc_data *data)
 {
 }

 #endif

 static int abeoz9_probe(struct i2c_client *client)
 {
 	struct abeoz9_rtc_data *data = NULL;
 	struct device *dev = &client->dev;
 	struct regmap *regmap;
 	int ret;

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 				     I2C_FUNC_SMBUS_BYTE_DATA |
 				     I2C_FUNC_SMBUS_I2C_BLOCK))
 		return -ENODEV;

 	regmap = devm_regmap_init_i2c(client, &abeoz9_rtc_regmap_config);
 	if (IS_ERR(regmap)) {
 		ret = PTR_ERR(regmap);
 		dev_err(dev, "regmap allocation failed: %d\n", ret);
 		return ret;
 	}

 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->regmap = regmap;
 	dev_set_drvdata(dev, data);

 	ret = abeoz9_rtc_setup(dev, client->dev.of_node);
 	if (ret)
 		return ret;

 	data->rtc = devm_rtc_allocate_device(dev);
 	ret = PTR_ERR_OR_ZERO(data->rtc);
 	if (ret)
 		return ret;

 	data->rtc->ops = &rtc_ops;
 	data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	data->rtc->range_max = RTC_TIMESTAMP_END_2099;
 	clear_bit(RTC_FEATURE_ALARM, data->rtc->features);

 	if (client->irq > 0) {
 		unsigned long irqflags = IRQF_TRIGGER_LOW;

 		if (dev_fwnode(&client->dev))
 			irqflags = 0;

 		ret = devm_request_threaded_irq(dev, client->irq, NULL,
 						abeoz9_rtc_irq,
 						irqflags | IRQF_ONESHOT,
 						dev_name(dev), dev);
 		if (ret) {
 			dev_err(dev, "failed to request alarm irq\n");
 			return ret;
 		}
 	} else {
 		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, data->rtc->features);
 	}

 	if (client->irq > 0 || device_property_read_bool(dev, "wakeup-source")) {
 		ret = device_init_wakeup(dev, true);
 		set_bit(RTC_FEATURE_ALARM, data->rtc->features);
 	}

 	ret = devm_rtc_register_device(data->rtc);
 	if (ret)
 		return ret;

 	abeoz9_hwmon_register(dev, data);
 	return 0;
 }

 #ifdef CONFIG_OF
 static const struct of_device_id abeoz9_dt_match[] = {
 	{ .compatible = "abracon,abeoz9" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, abeoz9_dt_match);
 #endif

 static const struct i2c_device_id abeoz9_id[] = {
 	{ "abeoz9" },
 	{ }
 };

 static struct i2c_driver abeoz9_driver = {
 	.driver = {
 		.name = "rtc-ab-eoz9",
 		.of_match_table = of_match_ptr(abeoz9_dt_match),
 	},
 	.probe = abeoz9_probe,
 	.id_table = abeoz9_id,
 };

 module_i2c_driver(abeoz9_driver);

 MODULE_AUTHOR("Artem Panfilov <panfilov.artyom@gmail.com>");
 MODULE_DESCRIPTION("Abracon AB-RTCMC-32.768kHz-EOZ9 RTC driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Real Time Clock driver for AB-RTCMC-32.768kHz-EOZ9 chip.
	* Copyright (C) 2019 Orolia
	*
	*/

	#include <linux/module.h>
	#include <linux/rtc.h>
	#include <linux/i2c.h>
	#include <linux/bcd.h>
	#include <linux/of.h>
	#include <linux/regmap.h>
	#include <linux/bitfield.h>
	#include <linux/hwmon.h>
	#include <linux/hwmon-sysfs.h>

	#define ABEOZ9_REG_CTRL1 0x00
	#define ABEOZ9_REG_CTRL1_MASK GENMASK(7, 0)
	#define ABEOZ9_REG_CTRL1_WE BIT(0)
	#define ABEOZ9_REG_CTRL1_TE BIT(1)
	#define ABEOZ9_REG_CTRL1_TAR BIT(2)
	#define ABEOZ9_REG_CTRL1_EERE BIT(3)
	#define ABEOZ9_REG_CTRL1_SRON BIT(4)
	#define ABEOZ9_REG_CTRL1_TD0 BIT(5)
	#define ABEOZ9_REG_CTRL1_TD1 BIT(6)
	#define ABEOZ9_REG_CTRL1_CLKINT BIT(7)

	#define ABEOZ9_REG_CTRL_INT 0x01
	#define ABEOZ9_REG_CTRL_INT_AIE BIT(0)
	#define ABEOZ9_REG_CTRL_INT_TIE BIT(1)
	#define ABEOZ9_REG_CTRL_INT_V1IE BIT(2)
	#define ABEOZ9_REG_CTRL_INT_V2IE BIT(3)
	#define ABEOZ9_REG_CTRL_INT_SRIE BIT(4)

	#define ABEOZ9_REG_CTRL_INT_FLAG 0x02
	#define ABEOZ9_REG_CTRL_INT_FLAG_AF BIT(0)
	#define ABEOZ9_REG_CTRL_INT_FLAG_TF BIT(1)
	#define ABEOZ9_REG_CTRL_INT_FLAG_V1IF BIT(2)
	#define ABEOZ9_REG_CTRL_INT_FLAG_V2IF BIT(3)
	#define ABEOZ9_REG_CTRL_INT_FLAG_SRF BIT(4)

	#define ABEOZ9_REG_CTRL_STATUS 0x03
	#define ABEOZ9_REG_CTRL_STATUS_V1F BIT(2)
	#define ABEOZ9_REG_CTRL_STATUS_V2F BIT(3)
	#define ABEOZ9_REG_CTRL_STATUS_SR BIT(4)
	#define ABEOZ9_REG_CTRL_STATUS_PON BIT(5)
	#define ABEOZ9_REG_CTRL_STATUS_EEBUSY BIT(7)

	#define ABEOZ9_REG_SEC 0x08
	#define ABEOZ9_REG_MIN 0x09
	#define ABEOZ9_REG_HOURS 0x0A
	#define ABEOZ9_HOURS_PM BIT(6)
	#define ABEOZ9_REG_DAYS 0x0B
	#define ABEOZ9_REG_WEEKDAYS 0x0C
	#define ABEOZ9_REG_MONTHS 0x0D
	#define ABEOZ9_REG_YEARS 0x0E

	#define ABEOZ9_SEC_LEN 7

	#define ABEOZ9_REG_ALARM_SEC 0x10
	#define ABEOZ9_BIT_ALARM_SEC GENMASK(6, 0)
	#define ABEOZ9_REG_ALARM_MIN 0x11
	#define ABEOZ9_BIT_ALARM_MIN GENMASK(6, 0)
	#define ABEOZ9_REG_ALARM_HOURS 0x12
	#define ABEOZ9_BIT_ALARM_HOURS_PM BIT(5)
	#define ABEOZ9_BIT_ALARM_HOURS GENMASK(4, 0)
	#define ABEOZ9_REG_ALARM_DAYS 0x13
	#define ABEOZ9_BIT_ALARM_DAYS GENMASK(5, 0)
	#define ABEOZ9_REG_ALARM_WEEKDAYS 0x14
	#define ABEOZ9_BIT_ALARM_WEEKDAYS GENMASK(2, 0)
	#define ABEOZ9_REG_ALARM_MONTHS 0x15
	#define ABEOZ9_BIT_ALARM_MONTHS GENMASK(4, 0)
	#define ABEOZ9_REG_ALARM_YEARS 0x16

	#define ABEOZ9_ALARM_LEN 7
	#define ABEOZ9_BIT_ALARM_AE BIT(7)

	#define ABEOZ9_REG_REG_TEMP 0x20
	#define ABEOZ953_TEMP_MAX 120
	#define ABEOZ953_TEMP_MIN -60

	#define ABEOZ9_REG_EEPROM 0x30
	#define ABEOZ9_REG_EEPROM_MASK GENMASK(8, 0)
	#define ABEOZ9_REG_EEPROM_THP BIT(0)
	#define ABEOZ9_REG_EEPROM_THE BIT(1)
	#define ABEOZ9_REG_EEPROM_FD0 BIT(2)
	#define ABEOZ9_REG_EEPROM_FD1 BIT(3)
	#define ABEOZ9_REG_EEPROM_R1K BIT(4)
	#define ABEOZ9_REG_EEPROM_R5K BIT(5)
	#define ABEOZ9_REG_EEPROM_R20K BIT(6)
	#define ABEOZ9_REG_EEPROM_R80K BIT(7)

	struct abeoz9_rtc_data {
	struct rtc_device *rtc;
	struct regmap *regmap;
	struct device *hwmon_dev;
	};

	static int abeoz9_check_validity(struct device *dev)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	int ret;
	int val;

	ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
	if (ret < 0) {
	dev_err(dev,
	"unable to get CTRL_STATUS register (%d)\n", ret);
	return ret;
	}

	if (val & ABEOZ9_REG_CTRL_STATUS_PON) {
	dev_warn(dev, "power-on reset detected, date is invalid\n");
	return -EINVAL;
	}

	if (val & ABEOZ9_REG_CTRL_STATUS_V1F) {
	dev_warn(dev,
	"voltage drops below VLOW1 threshold, date is invalid\n");
	return -EINVAL;
	}

	if ((val & ABEOZ9_REG_CTRL_STATUS_V2F)) {
	dev_warn(dev,
	"voltage drops below VLOW2 threshold, date is invalid\n");
	return -EINVAL;
	}

	return 0;
	}

	static int abeoz9_reset_validity(struct regmap *regmap)
	{
	return regmap_update_bits(regmap, ABEOZ9_REG_CTRL_STATUS,
	ABEOZ9_REG_CTRL_STATUS_V1F \|
	ABEOZ9_REG_CTRL_STATUS_V2F \|
	ABEOZ9_REG_CTRL_STATUS_PON,
	0);
	}

	static int abeoz9_rtc_get_time(struct device dev, struct rtc_time tm)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	u8 regs[ABEOZ9_SEC_LEN];
	int ret;

	ret = abeoz9_check_validity(dev);
	if (ret)
	return ret;

	ret = regmap_bulk_read(data->regmap, ABEOZ9_REG_SEC,
	regs,
	sizeof(regs));
	if (ret) {
	dev_err(dev, "reading RTC time failed (%d)\n", ret);
	return ret;
	}

	tm->tm_sec = bcd2bin(regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] & 0x7F);
	tm->tm_min = bcd2bin(regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] & 0x7F);

	if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM) {
	tm->tm_hour =
	bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & 0x1f);
	if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM)
	tm->tm_hour += 12;
	} else {
	tm->tm_hour = bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC]);
	}

	tm->tm_mday = bcd2bin(regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC]);
	tm->tm_wday = bcd2bin(regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC]);
	tm->tm_mon = bcd2bin(regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC]) - 1;
	tm->tm_year = bcd2bin(regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC]) + 100;

	return ret;
	}

	static int abeoz9_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	u8 regs[ABEOZ9_SEC_LEN];
	int ret;

	regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_sec);
	regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_min);
	regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_hour);
	regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mday);
	regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_wday);
	regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mon + 1);
	regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_year - 100);

	ret = regmap_bulk_write(data->regmap, ABEOZ9_REG_SEC,
	regs,
	sizeof(regs));

	if (ret) {
	dev_err(dev, "set RTC time failed (%d)\n", ret);
	return ret;
	}

	return abeoz9_reset_validity(regmap);
	}

	static int abeoz9_rtc_read_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	u8 regs[ABEOZ9_ALARM_LEN];
	u8 val[2];
	int ret;

	ret = abeoz9_check_validity(dev);
	if (ret)
	return ret;

	ret = regmap_bulk_read(regmap, ABEOZ9_REG_CTRL_INT, val, sizeof(val));
	if (ret)
	return ret;

	alarm->enabled = val[0] & ABEOZ9_REG_CTRL_INT_AIE;
	alarm->pending = val[1] & ABEOZ9_REG_CTRL_INT_FLAG_AF;

	ret = regmap_bulk_read(regmap, ABEOZ9_REG_ALARM_SEC, regs, sizeof(regs));
	if (ret)
	return ret;

	alarm->time.tm_sec = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_SEC, regs[0]));
	alarm->time.tm_min = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_MIN, regs[1]));
	alarm->time.tm_hour = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_HOURS, regs[2]));
	if (FIELD_GET(ABEOZ9_BIT_ALARM_HOURS_PM, regs[2]))
	alarm->time.tm_hour += 12;

	alarm->time.tm_mday = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_DAYS, regs[3]));

	return 0;
	}

	static int abeoz9_rtc_alarm_irq_enable(struct device *dev, u32 enable)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);

	return regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT,
	ABEOZ9_REG_CTRL_INT_AIE,
	FIELD_PREP(ABEOZ9_REG_CTRL_INT_AIE, enable));
	}

	static int abeoz9_rtc_set_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	u8 regs[ABEOZ9_ALARM_LEN] = {0};
	int ret;

	ret = regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG,
	ABEOZ9_REG_CTRL_INT_FLAG_AF, 0);
	if (ret)
	return ret;

	regs[0] = ABEOZ9_BIT_ALARM_AE \| FIELD_PREP(ABEOZ9_BIT_ALARM_SEC,
	bin2bcd(alarm->time.tm_sec));
	regs[1] = ABEOZ9_BIT_ALARM_AE \| FIELD_PREP(ABEOZ9_BIT_ALARM_MIN,
	bin2bcd(alarm->time.tm_min));
	regs[2] = ABEOZ9_BIT_ALARM_AE \| FIELD_PREP(ABEOZ9_BIT_ALARM_HOURS,
	bin2bcd(alarm->time.tm_hour));
	regs[3] = ABEOZ9_BIT_ALARM_AE \| FIELD_PREP(ABEOZ9_BIT_ALARM_DAYS,
	bin2bcd(alarm->time.tm_mday));

	ret = regmap_bulk_write(data->regmap, ABEOZ9_REG_ALARM_SEC, regs,
	sizeof(regs));
	if (ret)
	return ret;

	return abeoz9_rtc_alarm_irq_enable(dev, alarm->enabled);
	}

	static irqreturn_t abeoz9_rtc_irq(int irq, void *dev)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	unsigned int val;
	int ret;

	ret = regmap_read(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG, &val);
	if (ret)
	return IRQ_NONE;

	if (!FIELD_GET(ABEOZ9_REG_CTRL_INT_FLAG_AF, val))
	return IRQ_NONE;

	regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG,
	ABEOZ9_REG_CTRL_INT_FLAG_AF, 0);

	rtc_update_irq(data->rtc, 1, RTC_IRQF \| RTC_AF);

	return IRQ_HANDLED;
	}

	static int abeoz9_trickle_parse_dt(struct device_node *node)
	{
	u32 ohms = 0;

	if (of_property_read_u32(node, "trickle-resistor-ohms", &ohms))
	return 0;

	switch (ohms) {
	case 1000:
	return ABEOZ9_REG_EEPROM_R1K;
	case 5000:
	return ABEOZ9_REG_EEPROM_R5K;
	case 20000:
	return ABEOZ9_REG_EEPROM_R20K;
	case 80000:
	return ABEOZ9_REG_EEPROM_R80K;
	default:
	return 0;
	}
	}

	static int abeoz9_rtc_setup(struct device dev, struct device_node node)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	int ret;

	/* Enable Self Recovery, Clock for Watch and EEPROM refresh functions */
	ret = regmap_update_bits(regmap, ABEOZ9_REG_CTRL1,
	ABEOZ9_REG_CTRL1_MASK,
	ABEOZ9_REG_CTRL1_WE \|
	ABEOZ9_REG_CTRL1_EERE \|
	ABEOZ9_REG_CTRL1_SRON);
	if (ret < 0) {
	dev_err(dev, "unable to set CTRL_1 register (%d)\n", ret);
	return ret;
	}

	ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT, 0);
	if (ret < 0) {
	dev_err(dev,
	"unable to set control CTRL_INT register (%d)\n",
	ret);
	return ret;
	}

	ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT_FLAG, 0);
	if (ret < 0) {
	dev_err(dev,
	"unable to set control CTRL_INT_FLAG register (%d)\n",
	ret);
	return ret;
	}

	ret = abeoz9_trickle_parse_dt(node);

	/* Enable built-in termometer */
	ret \|= ABEOZ9_REG_EEPROM_THE;

	ret = regmap_update_bits(regmap, ABEOZ9_REG_EEPROM,
	ABEOZ9_REG_EEPROM_MASK,
	ret);
	if (ret < 0) {
	dev_err(dev, "unable to set EEPROM register (%d)\n", ret);
	return ret;
	}

	return ret;
	}

	static const struct rtc_class_ops rtc_ops = {
	.read_time = abeoz9_rtc_get_time,
	.set_time = abeoz9_rtc_set_time,
	.read_alarm = abeoz9_rtc_read_alarm,
	.set_alarm = abeoz9_rtc_set_alarm,
	.alarm_irq_enable = abeoz9_rtc_alarm_irq_enable,
	};

	static const struct regmap_config abeoz9_rtc_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0x3f,
	};

	#if IS_REACHABLE(CONFIG_HWMON)

	static int abeoz9z3_temp_read(struct device *dev,
	enum hwmon_sensor_types type,
	u32 attr, int channel, long *temp)
	{
	struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	int ret;
	unsigned int val;

	ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
	if (ret < 0)
	return ret;

	if ((val & ABEOZ9_REG_CTRL_STATUS_V1F) \|\|
	(val & ABEOZ9_REG_CTRL_STATUS_V2F)) {
	dev_err(dev,
	"thermometer might be disabled due to low voltage\n");
	return -EINVAL;
	}

	switch (attr) {
	case hwmon_temp_input:
	ret = regmap_read(regmap, ABEOZ9_REG_REG_TEMP, &val);
	if (ret < 0)
	return ret;
	temp = 1000 (val + ABEOZ953_TEMP_MIN);
	return 0;
	case hwmon_temp_max:
	temp = 1000 ABEOZ953_TEMP_MAX;
	return 0;
	case hwmon_temp_min:
	temp = 1000 ABEOZ953_TEMP_MIN;
	return 0;
	default:
	return -EOPNOTSUPP;
	}
	}

	static umode_t abeoz9_is_visible(const void *data,
	enum hwmon_sensor_types type,
	u32 attr, int channel)
	{
	switch (attr) {
	case hwmon_temp_input:
	case hwmon_temp_max:
	case hwmon_temp_min:
	return 0444;
	default:
	return 0;
	}
	}

	static const u32 abeoz9_chip_config[] = {
	HWMON_C_REGISTER_TZ,
	0
	};

	static const struct hwmon_channel_info abeoz9_chip = {
	.type = hwmon_chip,
	.config = abeoz9_chip_config,
	};

	static const u32 abeoz9_temp_config[] = {
	HWMON_T_INPUT \| HWMON_T_MAX \| HWMON_T_MIN,
	0
	};

	static const struct hwmon_channel_info abeoz9_temp = {
	.type = hwmon_temp,
	.config = abeoz9_temp_config,
	};

	static const struct hwmon_channel_info * const abeoz9_info[] = {
	&abeoz9_chip,
	&abeoz9_temp,
	NULL
	};

	static const struct hwmon_ops abeoz9_hwmon_ops = {
	.is_visible = abeoz9_is_visible,
	.read = abeoz9z3_temp_read,
	};

	static const struct hwmon_chip_info abeoz9_chip_info = {
	.ops = &abeoz9_hwmon_ops,
	.info = abeoz9_info,
	};

	static void abeoz9_hwmon_register(struct device *dev,
	struct abeoz9_rtc_data *data)
	{
	data->hwmon_dev =
	devm_hwmon_device_register_with_info(dev,
	"abeoz9",
	data,
	&abeoz9_chip_info,
	NULL);
	if (IS_ERR(data->hwmon_dev)) {
	dev_warn(dev, "unable to register hwmon device %ld\n",
	PTR_ERR(data->hwmon_dev));
	}
	}

	#else

	static void abeoz9_hwmon_register(struct device *dev,
	struct abeoz9_rtc_data *data)
	{
	}

	#endif

	static int abeoz9_probe(struct i2c_client *client)
	{
	struct abeoz9_rtc_data *data = NULL;
	struct device *dev = &client->dev;
	struct regmap *regmap;
	int ret;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C \|
	I2C_FUNC_SMBUS_BYTE_DATA \|
	I2C_FUNC_SMBUS_I2C_BLOCK))
	return -ENODEV;

	regmap = devm_regmap_init_i2c(client, &abeoz9_rtc_regmap_config);
	if (IS_ERR(regmap)) {
	ret = PTR_ERR(regmap);
	dev_err(dev, "regmap allocation failed: %d\n", ret);
	return ret;
	}

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->regmap = regmap;
	dev_set_drvdata(dev, data);

	ret = abeoz9_rtc_setup(dev, client->dev.of_node);
	if (ret)
	return ret;

	data->rtc = devm_rtc_allocate_device(dev);
	ret = PTR_ERR_OR_ZERO(data->rtc);
	if (ret)
	return ret;

	data->rtc->ops = &rtc_ops;
	data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
	data->rtc->range_max = RTC_TIMESTAMP_END_2099;
	clear_bit(RTC_FEATURE_ALARM, data->rtc->features);

	if (client->irq > 0) {
	unsigned long irqflags = IRQF_TRIGGER_LOW;

	if (dev_fwnode(&client->dev))
	irqflags = 0;

	ret = devm_request_threaded_irq(dev, client->irq, NULL,
	abeoz9_rtc_irq,
	irqflags \| IRQF_ONESHOT,
	dev_name(dev), dev);
	if (ret) {
	dev_err(dev, "failed to request alarm irq\n");
	return ret;
	}
	} else {
	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, data->rtc->features);
	}

	if (client->irq > 0 \|\| device_property_read_bool(dev, "wakeup-source")) {
	ret = device_init_wakeup(dev, true);
	set_bit(RTC_FEATURE_ALARM, data->rtc->features);
	}

	ret = devm_rtc_register_device(data->rtc);
	if (ret)
	return ret;

	abeoz9_hwmon_register(dev, data);
	return 0;
	}

	#ifdef CONFIG_OF
	static const struct of_device_id abeoz9_dt_match[] = {
	{ .compatible = "abracon,abeoz9" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, abeoz9_dt_match);
	#endif

	static const struct i2c_device_id abeoz9_id[] = {
	{ "abeoz9" },
	{ }
	};

	static struct i2c_driver abeoz9_driver = {
	.driver = {
	.name = "rtc-ab-eoz9",
	.of_match_table = of_match_ptr(abeoz9_dt_match),
	},
	.probe = abeoz9_probe,
	.id_table = abeoz9_id,
	};

	module_i2c_driver(abeoz9_driver);

	MODULE_AUTHOR("Artem Panfilov <panfilov.artyom@gmail.com>");
	MODULE_DESCRIPTION("Abracon AB-RTCMC-32.768kHz-EOZ9 RTC driver");
	MODULE_LICENSE("GPL");