[PATCH] rtc: rv3028: new driver

From: Alexandre Belloni
Date: Wed Jan 30 2019 - 10:07:32 EST

Add a driver for the MicroCrystal RV-3028.

Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
---
Documentation/devicetree/bindings/rtc/rtc.txt | 1 +
drivers/rtc/Kconfig | 9 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-rv3028.c | 732 ++++++++++++++++++
4 files changed, 743 insertions(+)
create mode 100644 drivers/rtc/rtc-rv3028.c

diff --git a/Documentation/devicetree/bindings/rtc/rtc.txt b/Documentation/devicetree/bindings/rtc/rtc.txt
index d86e2850fe1c..3e6a215e7304 100644
--- a/Documentation/devicetree/bindings/rtc/rtc.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc.txt
@@ -52,6 +52,7 @@ emmicro,em3027 EM Microelectronic EM3027 Real-time Clock
isil,isl1208 Intersil ISL1208 Low Power RTC with Battery Backed SRAM
isil,isl1218 Intersil ISL1218 Low Power RTC with Battery Backed SRAM
isil,isl12022 Intersil ISL12022 Real-time Clock
+microcrystal,rv3028 Real Time Clock Module with I2C-Bus
microcrystal,rv3029 Real Time Clock Module with I2C-Bus
microcrystal,rv8523 Real Time Clock
nxp,pcf2127 Real-time clock
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index faa9ae1a3062..845c7eef548a 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -626,6 +626,15 @@ config RTC_DRV_EM3027
This driver can also be built as a module. If so, the module
will be called rtc-em3027.

+config RTC_DRV_RV3028
+ tristate "Micro Crystal RV3028"
+ help
+ If you say yes here you get support for the Micro Crystal
+ RV3028.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-rv3028.
+
config RTC_DRV_RV8803
tristate "Micro Crystal RV8803, Epson RX8900"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index faca02109aaa..a701d68bb5ca 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -138,6 +138,7 @@ obj-$(CONFIG_RTC_DRV_RS5C313) += rtc-rs5c313.o
obj-$(CONFIG_RTC_DRV_RS5C348) += rtc-rs5c348.o
obj-$(CONFIG_RTC_DRV_RS5C372) += rtc-rs5c372.o
obj-$(CONFIG_RTC_DRV_RTD119X) += rtc-rtd119x.o
+obj-$(CONFIG_RTC_DRV_RV3028) += rtc-rv3028.o
obj-$(CONFIG_RTC_DRV_RV3029C2) += rtc-rv3029c2.o
obj-$(CONFIG_RTC_DRV_RV8803) += rtc-rv8803.o
obj-$(CONFIG_RTC_DRV_RX4581) += rtc-rx4581.o
diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
new file mode 100644
index 000000000000..cd1600feaed1
--- /dev/null
+++ b/drivers/rtc/rtc-rv3028.c
@@ -0,0 +1,732 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC driver for the Micro Crystal RV3028
+ *
+ * Copyright (C) 2018 Micro Crystal SA
+ *
+ * Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
+ *
+ */
+
+#include <linux/bcd.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/regmap.h>
+#include <linux/rtc.h>
+
+#define RV3028_SEC 0x00
+#define RV3028_MIN 0x01
+#define RV3028_HOUR 0x02
+#define RV3028_WDAY 0x03
+#define RV3028_DAY 0x04
+#define RV3028_MONTH 0x05
+#define RV3028_YEAR 0x06
+#define RV3028_ALARM_MIN 0x07
+#define RV3028_ALARM_HOUR 0x08
+#define RV3028_ALARM_DAY 0x09
+#define RV3028_STATUS 0x0E
+#define RV3028_CTRL1 0x0F
+#define RV3028_CTRL2 0x10
+#define RV3028_EVT_CTRL 0x13
+#define RV3028_TS_COUNT 0x14
+#define RV3028_TS_SEC 0x15
+#define RV3028_RAM1 0x1F
+#define RV3028_EEPROM_ADDR 0x25
+#define RV3028_EEPROM_DATA 0x26
+#define RV3028_EEPROM_CMD 0x27
+#define RV3028_CLKOUT 0x35
+#define RV3028_OFFSET 0x36
+#define RV3028_BACKUP 0x37
+
+#define RV3028_STATUS_PORF BIT(0)
+#define RV3028_STATUS_EVF BIT(1)
+#define RV3028_STATUS_AF BIT(2)
+#define RV3028_STATUS_TF BIT(3)
+#define RV3028_STATUS_UF BIT(4)
+#define RV3028_STATUS_BSF BIT(5)
+#define RV3028_STATUS_CLKF BIT(6)
+#define RV3028_STATUS_EEBUSY BIT(7)
+
+#define RV3028_CTRL1_EERD BIT(3)
+#define RV3028_CTRL1_WADA BIT(5)
+
+#define RV3028_CTRL2_RESET BIT(0)
+#define RV3028_CTRL2_12_24 BIT(1)
+#define RV3028_CTRL2_EIE BIT(2)
+#define RV3028_CTRL2_AIE BIT(3)
+#define RV3028_CTRL2_TIE BIT(4)
+#define RV3028_CTRL2_UIE BIT(5)
+#define RV3028_CTRL2_TSE BIT(7)
+
+#define RV3028_EVT_CTRL_TSR BIT(2)
+
+#define RV3028_EEPROM_CMD_WRITE 0x21
+#define RV3028_EEPROM_CMD_READ 0x22
+
+#define RV3028_EEBUSY_POLL 10000
+#define RV3028_EEBUSY_TIMEOUT 100000
+
+#define RV3028_BACKUP_TCE BIT(5)
+#define RV3028_BACKUP_TCR_MASK GENMASK(1,0)
+
+#define OFFSET_STEP_PPT 953674
+
+enum rv3028_type {
+ rv_3028,
+};
+
+struct rv3028_data {
+ struct regmap *regmap;
+ struct rtc_device *rtc;
+ enum rv3028_type type;
+};
+
+static u32 rv3028_trickle_resistors[] = {1000, 3000, 6000, 11000};
+
+static ssize_t timestamp0_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev->parent);
+
+ regmap_update_bits(rv3028->regmap, RV3028_EVT_CTRL, RV3028_EVT_CTRL_TSR,
+ RV3028_EVT_CTRL_TSR);
+
+ return count;
+};
+
+static ssize_t timestamp0_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev->parent);
+ struct rtc_time tm;
+ int ret, count;
+ u8 date[6];
+
+ ret = regmap_read(rv3028->regmap, RV3028_TS_COUNT, &count);
+ if (ret)
+ return ret;
+
+ if (!count)
+ return 0;
+
+ ret = regmap_bulk_read(rv3028->regmap, RV3028_TS_SEC, date,
+ sizeof(date));
+ if (ret)
+ return ret;
+
+ tm.tm_sec = bcd2bin(date[0]);
+ tm.tm_min = bcd2bin(date[1]);
+ tm.tm_hour = bcd2bin(date[2]);
+ tm.tm_mday = bcd2bin(date[3]);
+ tm.tm_mon = bcd2bin(date[4]) - 1;
+ tm.tm_year = bcd2bin(date[5]) + 100;
+
+ ret = rtc_valid_tm(&tm);
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%llu\n",
+ (unsigned long long)rtc_tm_to_time64(&tm));
+};
+
+static DEVICE_ATTR_RW(timestamp0);
+
+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;
+
+ ret = regmap_read(rv3028->regmap, RV3028_TS_COUNT, &count);
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%u\n", count);
+};
+
+static DEVICE_ATTR_RO(timestamp0_count);
+
+static struct attribute *rv3028_attrs[] = {
+ &dev_attr_timestamp0.attr,
+ &dev_attr_timestamp0_count.attr,
+ NULL
+};
+
+static const struct attribute_group rv3028_attr_group = {
+ .attrs = rv3028_attrs,
+};
+
+static irqreturn_t rv3028_handle_irq(int irq, void *dev_id)
+{
+ struct rv3028_data *rv3028 = dev_id;
+ unsigned long events = 0;
+ u32 status = 0, ctrl = 0;
+
+ if (regmap_read(rv3028->regmap, RV3028_STATUS, &status) < 0 ||
+ status == 0) {
+ return IRQ_NONE;
+ }
+
+ if (status & RV3028_STATUS_PORF)
+ dev_warn(&rv3028->rtc->dev, "Voltage low, data loss detected.\n");
+
+ if (status & RV3028_STATUS_TF) {
+ status |= RV3028_STATUS_TF;
+ ctrl |= RV3028_CTRL2_TIE;
+ events |= RTC_PF;
+ }
+
+ if (status & RV3028_STATUS_AF) {
+ status |= RV3028_STATUS_AF;
+ ctrl |= RV3028_CTRL2_AIE;
+ events |= RTC_AF;
+ }
+
+ if (status & RV3028_STATUS_UF) {
+ status |= RV3028_STATUS_UF;
+ ctrl |= RV3028_CTRL2_UIE;
+ events |= RTC_UF;
+ }
+
+ if (events) {
+ rtc_update_irq(rv3028->rtc, 1, events);
+ regmap_update_bits(rv3028->regmap, RV3028_STATUS, status, 0);
+ regmap_update_bits(rv3028->regmap, RV3028_CTRL2, ctrl, 0);
+ }
+
+ if (status & RV3028_STATUS_EVF) {
+ sysfs_notify(&rv3028->rtc->dev.kobj, NULL,
+ dev_attr_timestamp0.attr.name);
+ dev_warn(&rv3028->rtc->dev, "event detected");
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int rv3028_get_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ u8 date[7];
+ int ret, status;
+
+ ret = regmap_read(rv3028->regmap, RV3028_STATUS, &status);
+ if (ret < 0)
+ return ret;
+
+ if (status & RV3028_STATUS_PORF) {
+ dev_warn(dev, "Voltage low, data is invalid.\n");
+ return -EINVAL;
+ }
+
+ ret = regmap_bulk_read(rv3028->regmap, RV3028_SEC, date, sizeof(date));
+ if (ret)
+ return ret;
+
+ 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_mday = bcd2bin(date[RV3028_DAY] & 0x3f);
+ tm->tm_mon = bcd2bin(date[RV3028_MONTH] & 0x1f) - 1;
+ tm->tm_year = bcd2bin(date[RV3028_YEAR]) + 100;
+
+ return 0;
+}
+
+static int rv3028_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ u8 date[7];
+ int ret;
+
+ 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_DAY] = bin2bcd(tm->tm_mday);
+ date[RV3028_MONTH] = bin2bcd(tm->tm_mon + 1);
+ date[RV3028_YEAR] = bin2bcd(tm->tm_year - 100);
+
+ /*
+ * Writing to the Seconds register has the same effect as setting RESET
+ * bit to 1
+ */
+ ret = regmap_bulk_write(rv3028->regmap, RV3028_SEC, date,
+ sizeof(date));
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
+ RV3028_STATUS_PORF, 0);
+
+ return ret;
+}
+
+static int rv3028_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ u8 alarmvals[3];
+ int status, ctrl, ret;
+
+ ret = regmap_bulk_read(rv3028->regmap, RV3028_ALARM_MIN, alarmvals,
+ sizeof(alarmvals));
+ if (ret)
+ return ret;
+
+ ret = regmap_read(rv3028->regmap, RV3028_STATUS, &status);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read(rv3028->regmap, RV3028_CTRL2, &ctrl);
+ if (ret < 0)
+ return ret;
+
+ alrm->time.tm_sec = 0;
+ alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
+ alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
+ alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
+
+ alrm->enabled = !!(ctrl & RV3028_CTRL2_AIE);
+ alrm->pending = (status & RV3028_STATUS_AF) && alrm->enabled;
+
+ return 0;
+}
+
+static int rv3028_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ u8 alarmvals[3];
+ u8 ctrl = 0;
+ int ret;
+
+ /* The alarm has no seconds, round up to nearest minute */
+ if (alrm->time.tm_sec) {
+ time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
+
+ alarm_time += 60 - alrm->time.tm_sec;
+ rtc_time64_to_tm(alarm_time, &alrm->time);
+ }
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL2,
+ RV3028_CTRL2_AIE | RV3028_CTRL2_UIE, 0);
+ if (ret)
+ return ret;
+
+ alarmvals[0] = bin2bcd(alrm->time.tm_min);
+ alarmvals[1] = bin2bcd(alrm->time.tm_hour);
+ alarmvals[2] = bin2bcd(alrm->time.tm_mday);
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
+ RV3028_STATUS_AF, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_bulk_write(rv3028->regmap, RV3028_ALARM_MIN, alarmvals,
+ sizeof(alarmvals));
+ if (ret)
+ return ret;
+
+ if (alrm->enabled) {
+ if (rv3028->rtc->uie_rtctimer.enabled)
+ ctrl |= RV3028_CTRL2_UIE;
+ if (rv3028->rtc->aie_timer.enabled)
+ ctrl |= RV3028_CTRL2_AIE;
+ }
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL2,
+ RV3028_CTRL2_UIE | RV3028_CTRL2_AIE, ctrl);
+
+ return ret;
+}
+
+static int rv3028_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ int ctrl = 0, ret;
+
+ if (enabled) {
+ if (rv3028->rtc->uie_rtctimer.enabled)
+ ctrl |= RV3028_CTRL2_UIE;
+ if (rv3028->rtc->aie_timer.enabled)
+ ctrl |= RV3028_CTRL2_AIE;
+ }
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
+ RV3028_STATUS_AF | RV3028_STATUS_UF, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL2,
+ RV3028_CTRL2_UIE | RV3028_CTRL2_AIE, ctrl);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int rv3028_read_offset(struct device *dev, long *offset)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ int ret, value, steps;
+
+ ret = regmap_read(rv3028->regmap, RV3028_OFFSET, &value);
+ if (ret < 0)
+ return ret;
+
+ steps = sign_extend32(value << 1, 8);
+
+ ret = regmap_read(rv3028->regmap, RV3028_BACKUP, &value);
+ if (ret < 0)
+ return ret;
+
+ steps += value >> 7;
+
+ *offset = DIV_ROUND_CLOSEST(steps * OFFSET_STEP_PPT, 1000);
+
+ return 0;
+}
+
+static int rv3028_set_offset(struct device *dev, long offset)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ int ret;
+
+ offset = clamp(offset, -244141L, 243187L) * 1000;
+ offset = DIV_ROUND_CLOSEST(offset, OFFSET_STEP_PPT);
+
+ ret = regmap_write(rv3028->regmap, RV3028_OFFSET, offset >> 1);
+ if (ret < 0)
+ return ret;
+
+ return regmap_update_bits(rv3028->regmap, RV3028_BACKUP, BIT(7),
+ offset << 7);
+}
+
+static int rv3028_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+ struct rv3028_data *rv3028 = dev_get_drvdata(dev);
+ int status, ret = 0;
+
+ switch (cmd) {
+ case RTC_VL_READ:
+ ret = regmap_read(rv3028->regmap, RV3028_STATUS, &status);
+ if (ret < 0)
+ return ret;
+
+ if (status & RV3028_STATUS_PORF)
+ dev_warn(&rv3028->rtc->dev, "Voltage low, data loss detected.\n");
+
+ status &= RV3028_STATUS_PORF;
+
+ if (copy_to_user((void __user *)arg, &status, sizeof(int)))
+ return -EFAULT;
+
+ return 0;
+
+ case RTC_VL_CLR:
+ ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
+ RV3028_STATUS_PORF, 0);
+
+ return ret;
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+static int rv3028_nvram_write(void *priv, unsigned int offset, void *val,
+ size_t bytes)
+{
+ return regmap_bulk_write(priv, RV3028_RAM1 + offset, val, bytes);
+}
+
+static int rv3028_nvram_read(void *priv, unsigned int offset, void *val,
+ size_t bytes)
+{
+ return regmap_bulk_read(priv, RV3028_RAM1 + offset, val, bytes);
+}
+
+static int rv3028_eeprom_write(void *priv, unsigned int offset, void *val,
+ size_t bytes)
+{
+ u32 status, ctrl1;
+ int i, ret, err;
+ u8 *buf = val;
+
+ ret = regmap_read(priv, RV3028_CTRL1, &ctrl1);
+ 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);
+ if (ret)
+ goto restore_eerd;
+
+ ret = regmap_write(priv, RV3028_EEPROM_DATA, buf[i]);
+ if (ret)
+ goto restore_eerd;
+
+ ret = regmap_write(priv, RV3028_EEPROM_CMD, 0x0);
+ if (ret)
+ goto restore_eerd;
+
+ ret = regmap_write(priv, 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,
+ !(status & RV3028_STATUS_EEBUSY),
+ RV3028_EEBUSY_POLL,
+ RV3028_EEBUSY_TIMEOUT);
+ if (ret)
+ goto restore_eerd;
+ }
+
+restore_eerd:
+ if (!(ctrl1 & RV3028_CTRL1_EERD))
+ {
+ err = regmap_update_bits(priv, RV3028_CTRL1, RV3028_CTRL1_EERD,
+ 0);
+ if (err && !ret)
+ ret = err;
+ }
+
+ return ret;
+}
+
+static int rv3028_eeprom_read(void *priv, unsigned int offset, void *val,
+ size_t bytes)
+{
+ u32 status, ctrl1, data;
+ int i, ret, err;
+ u8 *buf = val;
+
+ ret = regmap_read(priv, RV3028_CTRL1, &ctrl1);
+ 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);
+ if (ret)
+ goto restore_eerd;
+
+ ret = regmap_write(priv, RV3028_EEPROM_CMD, 0x0);
+ if (ret)
+ goto restore_eerd;
+
+ ret = regmap_write(priv, RV3028_EEPROM_CMD,
+ RV3028_EEPROM_CMD_READ);
+ if (ret)
+ goto restore_eerd;
+
+ ret = regmap_read_poll_timeout(priv, 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);
+ 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;
+ }
+
+ return ret;
+}
+
+static struct rtc_class_ops rv3028_rtc_ops = {
+ .read_time = rv3028_get_time,
+ .set_time = rv3028_set_time,
+ .read_offset = rv3028_read_offset,
+ .set_offset = rv3028_set_offset,
+ .ioctl = rv3028_ioctl,
+};
+
+static const struct regmap_config regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = 0x37,
+};
+
+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,
+ .stride = 1,
+ .size = 2,
+ .type = NVMEM_TYPE_BATTERY_BACKED,
+ .reg_read = rv3028_nvram_read,
+ .reg_write = rv3028_nvram_write,
+ };
+ struct nvmem_config eeprom_cfg = {
+ .name = "rv3028_eeprom",
+ .word_size = 1,
+ .stride = 1,
+ .size = 43,
+ .type = NVMEM_TYPE_EEPROM,
+ .reg_read = rv3028_eeprom_read,
+ .reg_write = rv3028_eeprom_write,
+ };
+
+ rv3028 = devm_kzalloc(&client->dev, sizeof(struct rv3028_data),
+ GFP_KERNEL);
+ if (!rv3028)
+ return -ENOMEM;
+
+ rv3028->regmap = devm_regmap_init_i2c(client, &regmap_config);
+
+ i2c_set_clientdata(client, rv3028);
+
+ ret = regmap_read(rv3028->regmap, RV3028_STATUS, &status);
+ 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");
+
+ rv3028->rtc = devm_rtc_allocate_device(&client->dev);
+ if (IS_ERR(rv3028->rtc)) {
+ return PTR_ERR(rv3028->rtc);
+ }
+
+ if (client->irq > 0) {
+ ret = devm_request_threaded_irq(&client->dev, client->irq,
+ NULL, rv3028_handle_irq,
+ IRQF_TRIGGER_LOW | 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;
+ }
+ }
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL1,
+ RV3028_CTRL1_WADA, RV3028_CTRL1_WADA);
+ if (ret)
+ return ret;
+
+ /* setup timestamping */
+ ret = regmap_update_bits(rv3028->regmap, RV3028_CTRL2,
+ RV3028_CTRL2_EIE | RV3028_CTRL2_TSE,
+ RV3028_CTRL2_EIE | RV3028_CTRL2_TSE);
+ 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 = rtc_add_group(rv3028->rtc, &rv3028_attr_group);
+ if (ret)
+ return ret;
+
+ 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);
+ 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);
+
+ rv3028->rtc->max_user_freq = 1;
+
+ return 0;
+}
+
+static const struct of_device_id rv3028_of_match[] = {
+ { .compatible = "microcrystal,rv3028", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, rv3028_of_match);
+
+static struct i2c_driver rv3028_driver = {
+ .driver = {
+ .name = "rtc-rv3028",
+ .of_match_table = of_match_ptr(rv3028_of_match),
+ },
+ .probe_new = rv3028_probe,
+};
+module_i2c_driver(rv3028_driver);
+
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Micro Crystal RV3028 RTC driver");
+MODULE_LICENSE("GPL v2");
--
2.20.1