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kernel/drivers/rtc/rtc-rv3028.c
Alexandre Belloni e6e7376cfd rtc: rv3028: add new driver 
Add a driver for the MicroCrystal RV-3028. It is a SMT Real-Time Clock
Module that incorporates an integrated CMOS circuit together with an XTAL.
It has an i2c interface.

The driver handles date/time, alarms, trickle charging, timestamping,
frequency offset correction, EEPROM and NVRAM.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2019-02-17 21:29:10 +01:00

732 lines
17 KiB
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// SPDX-License-Identifier: GPL-2.0
/*
* RTC driver for the Micro Crystal RV3028
*
* Copyright (C) 2019 Micro Crystal SA
*
* Alexandre Belloni <alexandre.belloni@bootlin.com>
*
*/
#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 u16 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@bootlin.com>");
MODULE_DESCRIPTION("Micro Crystal RV3028 RTC driver");
MODULE_LICENSE("GPL v2");
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