1 files changed, 323 insertions, 124 deletions

diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index ec84db0b3d7a..c2a531f0e125 100644
--- a/drivers/rtc/rtc-rv3028.c
+++ b/drivers/rtc/rtc-rv3028.c
@@ -10,13 +10,14 @@
 
 #include <linux/clk-provider.h>
 #include <linux/bcd.h>
+#include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/log2.h>
 #include <linux/module.h>
-#include <linux/of_device.h>
+#include <linux/of.h>
 #include <linux/regmap.h>
 #include <linux/rtc.h>
 
@@ -71,6 +72,7 @@
 
 #define RV3028_EVT_CTRL_TSR		BIT(2)
 
+#define RV3028_EEPROM_CMD_UPDATE	0x11
 #define RV3028_EEPROM_CMD_WRITE		0x21
 #define RV3028_EEPROM_CMD_READ		0x22
 
@@ -79,6 +81,10 @@
 
 #define RV3028_BACKUP_TCE		BIT(5)
 #define RV3028_BACKUP_TCR_MASK		GENMASK(1,0)
+#define RV3028_BACKUP_BSM		GENMASK(3,2)
+
+#define RV3028_BACKUP_BSM_DSM		0x1
+#define RV3028_BACKUP_BSM_LSM		0x3
 
 #define OFFSET_STEP_PPT			953674
 
@@ -95,7 +101,7 @@ struct rv3028_data {
 #endif
 };
 
-static u16 rv3028_trickle_resistors[] = {1000, 3000, 6000, 11000};
+static u16 rv3028_trickle_resistors[] = {3000, 5000, 9000, 15000};
 
 static ssize_t timestamp0_store(struct device *dev,
 				struct device_attribute *attr,
@@ -114,8 +120,9 @@ static ssize_t timestamp0_show(struct device *dev,
 {
 	struct rv3028_data *rv3028 = dev_get_drvdata(dev->parent);
 	struct rtc_time tm;
-	int ret, count;
+	unsigned int count;
 	u8 date[6];
+	int ret;
 
 	ret = regmap_read(rv3028->regmap, RV3028_TS_COUNT, &count);
 	if (ret)
@@ -150,7 +157,8 @@ static ssize_t timestamp0_count_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
 	struct rv3028_data *rv3028 = dev_get_drvdata(dev->parent);
-	int ret, count;
+	unsigned int count;
+	int ret;
 
 	ret = regmap_read(rv3028->regmap, RV3028_TS_COUNT, &count);
 	if (ret)
@@ -171,6 +179,88 @@ static const struct attribute_group rv3028_attr_group = {
 	.attrs	= rv3028_attrs,
 };
 
+static int rv3028_exit_eerd(struct rv3028_data *rv3028, u32 eerd)
+{
+	if (eerd)
+		return 0;
+
+	return regmap_update_bits(rv3028->regmap, RV3028_CTRL1, RV3028_CTRL1_EERD, 0);
+}
+
+static int rv3028_enter_eerd(struct rv3028_data *rv3028, u32 *eerd)
+{
+	u32 ctrl1, status;
+	int ret;
+
+	ret = regmap_read(rv3028->regmap, RV3028_CTRL1, &ctrl1);
+	if (ret)
+		return ret;
+
+	*eerd = ctrl1 & RV3028_CTRL1_EERD;
+	if (*eerd)
+		return 0;
+
+	ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL1,
+				 RV3028_CTRL1_EERD, RV3028_CTRL1_EERD);
+	if (ret)
+		return ret;
+
+	ret = regmap_read_poll_timeout(rv3028->regmap, RV3028_STATUS, status,
+				       !(status & RV3028_STATUS_EEBUSY),
+				       RV3028_EEBUSY_POLL, RV3028_EEBUSY_TIMEOUT);
+	if (ret) {
+		rv3028_exit_eerd(rv3028, *eerd);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rv3028_update_eeprom(struct rv3028_data *rv3028, u32 eerd)
+{
+	u32 status;
+	int ret;
+
+	ret = regmap_write(rv3028->regmap, RV3028_EEPROM_CMD, 0x0);
+	if (ret)
+		goto exit_eerd;
+
+	ret = regmap_write(rv3028->regmap, RV3028_EEPROM_CMD, RV3028_EEPROM_CMD_UPDATE);
+	if (ret)
+		goto exit_eerd;
+
+	usleep_range(63000, RV3028_EEBUSY_TIMEOUT);
+
+	ret = regmap_read_poll_timeout(rv3028->regmap, RV3028_STATUS, status,
+				       !(status & RV3028_STATUS_EEBUSY),
+				       RV3028_EEBUSY_POLL, RV3028_EEBUSY_TIMEOUT);
+
+exit_eerd:
+	rv3028_exit_eerd(rv3028, eerd);
+
+	return ret;
+}
+
+static int rv3028_update_cfg(struct rv3028_data *rv3028, unsigned int reg,
+			     unsigned int mask, unsigned int val)
+{
+	u32 eerd;
+	int ret;
+
+	ret = rv3028_enter_eerd(rv3028, &eerd);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(rv3028->regmap, reg, mask, val);
+	if (ret) {
+		rv3028_exit_eerd(rv3028, eerd);
+		return ret;
+	}
+
+	return rv3028_update_eeprom(rv3028, eerd);
+}
+
 static irqreturn_t rv3028_handle_irq(int irq, void *dev_id)
 {
 	struct rv3028_data *rv3028 = dev_id;
@@ -182,8 +272,7 @@ static irqreturn_t rv3028_handle_irq(int irq, void *dev_id)
 		return IRQ_NONE;
 	}
 
-	if (status & RV3028_STATUS_PORF)
-		dev_warn(&rv3028->rtc->dev, "Voltage low, data loss detected.\n");
+	status &= ~RV3028_STATUS_PORF;
 
 	if (status & RV3028_STATUS_TF) {
 		status |= RV3028_STATUS_TF;
@@ -228,10 +317,8 @@ static int rv3028_get_time(struct device *dev, struct rtc_time *tm)
 	if (ret < 0)
 		return ret;
 
-	if (status & RV3028_STATUS_PORF) {
-		dev_warn(dev, "Voltage low, data is invalid.\n");
+	if (status & RV3028_STATUS_PORF)
 		return -EINVAL;
-	}
 
 	ret = regmap_bulk_read(rv3028->regmap, RV3028_SEC, date, sizeof(date));
 	if (ret)
@@ -240,7 +327,7 @@ static int rv3028_get_time(struct device *dev, struct rtc_time *tm)
 	tm->tm_sec  = bcd2bin(date[RV3028_SEC] & 0x7f);
 	tm->tm_min  = bcd2bin(date[RV3028_MIN] & 0x7f);
 	tm->tm_hour = bcd2bin(date[RV3028_HOUR] & 0x3f);
-	tm->tm_wday = ilog2(date[RV3028_WDAY] & 0x7f);
+	tm->tm_wday = date[RV3028_WDAY] & 0x7f;
 	tm->tm_mday = bcd2bin(date[RV3028_DAY] & 0x3f);
 	tm->tm_mon  = bcd2bin(date[RV3028_MONTH] & 0x1f) - 1;
 	tm->tm_year = bcd2bin(date[RV3028_YEAR]) + 100;
@@ -257,7 +344,7 @@ static int rv3028_set_time(struct device *dev, struct rtc_time *tm)
 	date[RV3028_SEC]   = bin2bcd(tm->tm_sec);
 	date[RV3028_MIN]   = bin2bcd(tm->tm_min);
 	date[RV3028_HOUR]  = bin2bcd(tm->tm_hour);
-	date[RV3028_WDAY]  = 1 << (tm->tm_wday);
+	date[RV3028_WDAY]  = tm->tm_wday;
 	date[RV3028_DAY]   = bin2bcd(tm->tm_mday);
 	date[RV3028_MONTH] = bin2bcd(tm->tm_mon + 1);
 	date[RV3028_YEAR]  = bin2bcd(tm->tm_year - 100);
@@ -404,17 +491,96 @@ static int rv3028_read_offset(struct device *dev, long *offset)
 static int rv3028_set_offset(struct device *dev, long offset)
 {
 	struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+	u32 eerd;
 	int ret;
 
 	offset = clamp(offset, -244141L, 243187L) * 1000;
 	offset = DIV_ROUND_CLOSEST(offset, OFFSET_STEP_PPT);
 
+	ret = rv3028_enter_eerd(rv3028, &eerd);
+	if (ret)
+		return ret;
+
 	ret = regmap_write(rv3028->regmap, RV3028_OFFSET, offset >> 1);
 	if (ret < 0)
-		return ret;
+		goto exit_eerd;
+
+	ret = regmap_update_bits(rv3028->regmap, RV3028_BACKUP, BIT(7),
+				 offset << 7);
+	if (ret < 0)
+		goto exit_eerd;
+
+	return rv3028_update_eeprom(rv3028, eerd);
+
+exit_eerd:
+	rv3028_exit_eerd(rv3028, eerd);
+
+	return ret;
+
+}
+
+static int rv3028_param_get(struct device *dev, struct rtc_param *param)
+{
+	struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+	int ret;
+	u32 value;
+
+	switch(param->param) {
+	case RTC_PARAM_BACKUP_SWITCH_MODE:
+		ret = regmap_read(rv3028->regmap, RV3028_BACKUP, &value);
+		if (ret < 0)
+			return ret;
+
+		value = FIELD_GET(RV3028_BACKUP_BSM, value);
+
+		switch(value) {
+		case RV3028_BACKUP_BSM_DSM:
+			param->uvalue = RTC_BSM_DIRECT;
+			break;
+		case RV3028_BACKUP_BSM_LSM:
+			param->uvalue = RTC_BSM_LEVEL;
+			break;
+		default:
+			param->uvalue = RTC_BSM_DISABLED;
+		}
+		break;
 
-	return regmap_update_bits(rv3028->regmap, RV3028_BACKUP, BIT(7),
-				  offset << 7);
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int rv3028_param_set(struct device *dev, struct rtc_param *param)
+{
+	struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+	u8 mode;
+
+	switch(param->param) {
+	case RTC_PARAM_BACKUP_SWITCH_MODE:
+		switch (param->uvalue) {
+		case RTC_BSM_DISABLED:
+			mode = 0;
+			break;
+		case RTC_BSM_DIRECT:
+			mode = RV3028_BACKUP_BSM_DSM;
+			break;
+		case RTC_BSM_LEVEL:
+			mode = RV3028_BACKUP_BSM_LSM;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		return rv3028_update_cfg(rv3028, RV3028_BACKUP, RV3028_BACKUP_BSM,
+					 FIELD_PREP(RV3028_BACKUP_BSM, mode));
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
 }
 
 static int rv3028_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
@@ -451,49 +617,36 @@ static int rv3028_nvram_read(void *priv, unsigned int offset, void *val,
 static int rv3028_eeprom_write(void *priv, unsigned int offset, void *val,
 			       size_t bytes)
 {
-	u32 status, ctrl1;
-	int i, ret, err;
+	struct rv3028_data *rv3028 = priv;
+	u32 status, eerd;
+	int i, ret;
 	u8 *buf = val;
 
-	ret = regmap_read(priv, RV3028_CTRL1, &ctrl1);
+	ret = rv3028_enter_eerd(rv3028, &eerd);
 	if (ret)
 		return ret;
 
-	if (!(ctrl1 & RV3028_CTRL1_EERD)) {
-		ret = regmap_update_bits(priv, RV3028_CTRL1,
-					 RV3028_CTRL1_EERD, RV3028_CTRL1_EERD);
-		if (ret)
-			return ret;
-
-		ret = regmap_read_poll_timeout(priv, RV3028_STATUS, status,
-					       !(status & RV3028_STATUS_EEBUSY),
-					       RV3028_EEBUSY_POLL,
-					       RV3028_EEBUSY_TIMEOUT);
-		if (ret)
-			goto restore_eerd;
-	}
-
 	for (i = 0; i < bytes; i++) {
-		ret = regmap_write(priv, RV3028_EEPROM_ADDR, offset + i);
+		ret = regmap_write(rv3028->regmap, RV3028_EEPROM_ADDR, offset + i);
 		if (ret)
 			goto restore_eerd;
 
-		ret = regmap_write(priv, RV3028_EEPROM_DATA, buf[i]);
+		ret = regmap_write(rv3028->regmap, RV3028_EEPROM_DATA, buf[i]);
 		if (ret)
 			goto restore_eerd;
 
-		ret = regmap_write(priv, RV3028_EEPROM_CMD, 0x0);
+		ret = regmap_write(rv3028->regmap, RV3028_EEPROM_CMD, 0x0);
 		if (ret)
 			goto restore_eerd;
 
-		ret = regmap_write(priv, RV3028_EEPROM_CMD,
+		ret = regmap_write(rv3028->regmap, RV3028_EEPROM_CMD,
 				   RV3028_EEPROM_CMD_WRITE);
 		if (ret)
 			goto restore_eerd;
 
 		usleep_range(RV3028_EEBUSY_POLL, RV3028_EEBUSY_TIMEOUT);
 
-		ret = regmap_read_poll_timeout(priv, RV3028_STATUS, status,
+		ret = regmap_read_poll_timeout(rv3028->regmap, RV3028_STATUS, status,
 					       !(status & RV3028_STATUS_EEBUSY),
 					       RV3028_EEBUSY_POLL,
 					       RV3028_EEBUSY_TIMEOUT);
@@ -502,13 +655,7 @@ static int rv3028_eeprom_write(void *priv, unsigned int offset, void *val,
 	}
 
 restore_eerd:
-	if (!(ctrl1 & RV3028_CTRL1_EERD))
-	{
-		err = regmap_update_bits(priv, RV3028_CTRL1, RV3028_CTRL1_EERD,
-					 0);
-		if (err && !ret)
-			ret = err;
-	}
+	rv3028_exit_eerd(rv3028, eerd);
 
 	return ret;
 }
@@ -516,63 +663,44 @@ restore_eerd:
 static int rv3028_eeprom_read(void *priv, unsigned int offset, void *val,
 			      size_t bytes)
 {
-	u32 status, ctrl1, data;
-	int i, ret, err;
+	struct rv3028_data *rv3028 = priv;
+	u32 status, eerd, data;
+	int i, ret;
 	u8 *buf = val;
 
-	ret = regmap_read(priv, RV3028_CTRL1, &ctrl1);
+	ret = rv3028_enter_eerd(rv3028, &eerd);
 	if (ret)
 		return ret;
 
-	if (!(ctrl1 & RV3028_CTRL1_EERD)) {
-		ret = regmap_update_bits(priv, RV3028_CTRL1,
-					 RV3028_CTRL1_EERD, RV3028_CTRL1_EERD);
-		if (ret)
-			return ret;
-
-		ret = regmap_read_poll_timeout(priv, RV3028_STATUS, status,
-					       !(status & RV3028_STATUS_EEBUSY),
-					       RV3028_EEBUSY_POLL,
-					       RV3028_EEBUSY_TIMEOUT);
-		if (ret)
-			goto restore_eerd;
-	}
-
 	for (i = 0; i < bytes; i++) {
-		ret = regmap_write(priv, RV3028_EEPROM_ADDR, offset + i);
+		ret = regmap_write(rv3028->regmap, RV3028_EEPROM_ADDR, offset + i);
 		if (ret)
 			goto restore_eerd;
 
-		ret = regmap_write(priv, RV3028_EEPROM_CMD, 0x0);
+		ret = regmap_write(rv3028->regmap, RV3028_EEPROM_CMD, 0x0);
 		if (ret)
 			goto restore_eerd;
 
-		ret = regmap_write(priv, RV3028_EEPROM_CMD,
+		ret = regmap_write(rv3028->regmap, RV3028_EEPROM_CMD,
 				   RV3028_EEPROM_CMD_READ);
 		if (ret)
 			goto restore_eerd;
 
-		ret = regmap_read_poll_timeout(priv, RV3028_STATUS, status,
+		ret = regmap_read_poll_timeout(rv3028->regmap, RV3028_STATUS, status,
 					       !(status & RV3028_STATUS_EEBUSY),
 					       RV3028_EEBUSY_POLL,
 					       RV3028_EEBUSY_TIMEOUT);
 		if (ret)
 			goto restore_eerd;
 
-		ret = regmap_read(priv, RV3028_EEPROM_DATA, &data);
+		ret = regmap_read(rv3028->regmap, RV3028_EEPROM_DATA, &data);
 		if (ret)
 			goto restore_eerd;
 		buf[i] = data;
 	}
 
 restore_eerd:
-	if (!(ctrl1 & RV3028_CTRL1_EERD))
-	{
-		err = regmap_update_bits(priv, RV3028_CTRL1, RV3028_CTRL1_EERD,
-					 0);
-		if (err && !ret)
-			ret = err;
-	}
+	rv3028_exit_eerd(rv3028, eerd);
 
 	return ret;
 }
@@ -603,14 +731,19 @@ static unsigned long rv3028_clkout_recalc_rate(struct clk_hw *hw,
 	return clkout_rates[clkout];
 }
 
-static long rv3028_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
-				     unsigned long *prate)
+static int rv3028_clkout_determine_rate(struct clk_hw *hw,
+					struct clk_rate_request *req)
 {
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
-		if (clkout_rates[i] <= rate)
-			return clkout_rates[i];
+		if (clkout_rates[i] <= req->rate) {
+			req->rate = clkout_rates[i];
+
+			return 0;
+		}
+
+	req->rate = clkout_rates[0];
 
 	return 0;
 }
@@ -619,24 +752,23 @@ static int rv3028_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
 				  unsigned long parent_rate)
 {
 	int i, ret;
+	u32 enabled;
 	struct rv3028_data *rv3028 = clkout_hw_to_rv3028(hw);
 
+	ret = regmap_read(rv3028->regmap, RV3028_CLKOUT, &enabled);
+	if (ret < 0)
+		return ret;
+
 	ret = regmap_write(rv3028->regmap, RV3028_CLKOUT, 0x0);
 	if (ret < 0)
 		return ret;
 
-	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++) {
-		if (clkout_rates[i] == rate) {
-			ret = regmap_update_bits(rv3028->regmap,
-						 RV3028_CLKOUT,
-						 RV3028_CLKOUT_FD_MASK, i);
-			if (ret < 0)
-				return ret;
+	enabled &= RV3028_CLKOUT_CLKOE;
 
-			return regmap_write(rv3028->regmap, RV3028_CLKOUT,
-				RV3028_CLKOUT_CLKSY | RV3028_CLKOUT_CLKOE);
-		}
-	}
+	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
+		if (clkout_rates[i] == rate)
+			return rv3028_update_cfg(rv3028, RV3028_CLKOUT, 0xff,
+						 RV3028_CLKOUT_CLKSY | enabled | i);
 
 	return -EINVAL;
 }
@@ -675,7 +807,7 @@ static const struct clk_ops rv3028_clkout_ops = {
 	.unprepare = rv3028_clkout_unprepare,
 	.is_prepared = rv3028_clkout_is_prepared,
 	.recalc_rate = rv3028_clkout_recalc_rate,
-	.round_rate = rv3028_clkout_round_rate,
+	.determine_rate = rv3028_clkout_determine_rate,
 	.set_rate = rv3028_clkout_set_rate,
 };
 
@@ -711,12 +843,17 @@ static int rv3028_clkout_register_clk(struct rv3028_data *rv3028,
 }
 #endif
 
-static struct rtc_class_ops rv3028_rtc_ops = {
+static const struct rtc_class_ops rv3028_rtc_ops = {
 	.read_time = rv3028_get_time,
 	.set_time = rv3028_set_time,
+	.read_alarm = rv3028_get_alarm,
+	.set_alarm = rv3028_set_alarm,
+	.alarm_irq_enable = rv3028_alarm_irq_enable,
 	.read_offset = rv3028_read_offset,
 	.set_offset = rv3028_set_offset,
 	.ioctl = rv3028_ioctl,
+	.param_get = rv3028_param_get,
+	.param_set = rv3028_param_set,
 };
 
 static const struct regmap_config regmap_config = {
@@ -725,11 +862,68 @@ static const struct regmap_config regmap_config = {
         .max_register = 0x37,
 };
 
+static u8 rv3028_set_trickle_charger(struct rv3028_data *rv3028,
+				     struct i2c_client *client)
+{
+	int ret, val_old, val;
+	u32 ohms, chargeable;
+
+	ret = regmap_read(rv3028->regmap, RV3028_BACKUP, &val_old);
+	if (ret < 0)
+		return ret;
+
+	/* mask out only trickle charger bits */
+	val_old = val_old & (RV3028_BACKUP_TCE | RV3028_BACKUP_TCR_MASK);
+	val = val_old;
+
+	/* setup trickle charger */
+	if (!device_property_read_u32(&client->dev, "trickle-resistor-ohms",
+				      &ohms)) {
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(rv3028_trickle_resistors); i++)
+			if (ohms == rv3028_trickle_resistors[i])
+				break;
+
+		if (i < ARRAY_SIZE(rv3028_trickle_resistors)) {
+			/* enable trickle charger and its resistor */
+			val = RV3028_BACKUP_TCE | i;
+		} else {
+			dev_warn(&client->dev, "invalid trickle resistor value\n");
+		}
+	}
+
+	if (!device_property_read_u32(&client->dev, "aux-voltage-chargeable",
+				      &chargeable)) {
+		switch (chargeable) {
+		case 0:
+			val &= ~RV3028_BACKUP_TCE;
+			break;
+		case 1:
+			val |= RV3028_BACKUP_TCE;
+			break;
+		default:
+			dev_warn(&client->dev,
+				 "unsupported aux-voltage-chargeable value\n");
+			break;
+		}
+	}
+
+	/* only update EEPROM if changes are necessary */
+	if (val_old != val) {
+		ret = rv3028_update_cfg(rv3028, RV3028_BACKUP, RV3028_BACKUP_TCE |
+						RV3028_BACKUP_TCR_MASK, val);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
+}
+
 static int rv3028_probe(struct i2c_client *client)
 {
 	struct rv3028_data *rv3028;
 	int ret, status;
-	u32 ohms;
 	struct nvmem_config nvmem_cfg = {
 		.name = "rv3028_nvram",
 		.word_size = 1,
@@ -764,9 +958,6 @@ static int rv3028_probe(struct i2c_client *client)
 	if (ret < 0)
 		return ret;
 
-	if (status & RV3028_STATUS_PORF)
-		dev_warn(&client->dev, "Voltage low, data loss detected.\n");
-
 	if (status & RV3028_STATUS_AF)
 		dev_warn(&client->dev, "An alarm may have been missed.\n");
 
@@ -775,19 +966,28 @@ static int rv3028_probe(struct i2c_client *client)
 		return PTR_ERR(rv3028->rtc);
 
 	if (client->irq > 0) {
+		unsigned long flags;
+
+		/*
+		 * If flags = 0, devm_request_threaded_irq() will use IRQ flags
+		 * obtained from device tree.
+		 */
+		if (dev_fwnode(&client->dev))
+			flags = 0;
+		else
+			flags = IRQF_TRIGGER_LOW;
+
 		ret = devm_request_threaded_irq(&client->dev, client->irq,
 						NULL, rv3028_handle_irq,
-						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+						flags | IRQF_ONESHOT,
 						"rv3028", rv3028);
 		if (ret) {
 			dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
 			client->irq = 0;
-		} else {
-			rv3028_rtc_ops.read_alarm = rv3028_get_alarm;
-			rv3028_rtc_ops.set_alarm = rv3028_set_alarm;
-			rv3028_rtc_ops.alarm_irq_enable = rv3028_alarm_irq_enable;
 		}
 	}
+	if (!client->irq)
+		clear_bit(RTC_FEATURE_ALARM, rv3028->rtc->features);
 
 	ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL1,
 				 RV3028_CTRL1_WADA, RV3028_CTRL1_WADA);
@@ -801,42 +1001,27 @@ static int rv3028_probe(struct i2c_client *client)
 	if (ret)
 		return ret;
 
-	/* setup trickle charger */
-	if (!device_property_read_u32(&client->dev, "trickle-resistor-ohms",
-				      &ohms)) {
-		int i;
-
-		for (i = 0; i < ARRAY_SIZE(rv3028_trickle_resistors); i++)
-			if (ohms == rv3028_trickle_resistors[i])
-				break;
-
-		if (i < ARRAY_SIZE(rv3028_trickle_resistors)) {
-			ret = regmap_update_bits(rv3028->regmap, RV3028_BACKUP,
-						 RV3028_BACKUP_TCE |
-						 RV3028_BACKUP_TCR_MASK,
-						 RV3028_BACKUP_TCE | i);
-			if (ret)
-				return ret;
-		} else {
-			dev_warn(&client->dev, "invalid trickle resistor value\n");
-		}
-	}
+	ret = rv3028_set_trickle_charger(rv3028, client);
+	if (ret)
+		return ret;
 
 	ret = rtc_add_group(rv3028->rtc, &rv3028_attr_group);
 	if (ret)
 		return ret;
 
+	set_bit(RTC_FEATURE_BACKUP_SWITCH_MODE, rv3028->rtc->features);
+
 	rv3028->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	rv3028->rtc->range_max = RTC_TIMESTAMP_END_2099;
 	rv3028->rtc->ops = &rv3028_rtc_ops;
-	ret = rtc_register_device(rv3028->rtc);
+	ret = devm_rtc_register_device(rv3028->rtc);
 	if (ret)
 		return ret;
 
 	nvmem_cfg.priv = rv3028->regmap;
-	rtc_nvmem_register(rv3028->rtc, &nvmem_cfg);
-	eeprom_cfg.priv = rv3028->regmap;
-	rtc_nvmem_register(rv3028->rtc, &eeprom_cfg);
+	devm_rtc_nvmem_register(rv3028->rtc, &nvmem_cfg);
+	eeprom_cfg.priv = rv3028;
+	devm_rtc_nvmem_register(rv3028->rtc, &eeprom_cfg);
 
 	rv3028->rtc->max_user_freq = 1;
 
@@ -846,18 +1031,32 @@ static int rv3028_probe(struct i2c_client *client)
 	return 0;
 }
 
-static const struct of_device_id rv3028_of_match[] = {
+static const struct acpi_device_id rv3028_i2c_acpi_match[] = {
+	{ "MCRY3028" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, rv3028_i2c_acpi_match);
+
+static const __maybe_unused struct of_device_id rv3028_of_match[] = {
 	{ .compatible = "microcrystal,rv3028", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, rv3028_of_match);
 
+static const struct i2c_device_id rv3028_id_table[] = {
+	{ .name = "rv3028", },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rv3028_id_table);
+
 static struct i2c_driver rv3028_driver = {
 	.driver = {
 		.name = "rtc-rv3028",
+		.acpi_match_table = rv3028_i2c_acpi_match,
 		.of_match_table = of_match_ptr(rv3028_of_match),
 	},
-	.probe_new	= rv3028_probe,
+	.id_table	= rv3028_id_table,
+	.probe		= rv3028_probe,
 };
 module_i2c_driver(rv3028_driver);