// SPDX-License-Identifier: GPL-2.0
/*
* RTC driver for the Micro Crystal RV8803
*
* Copyright (C) 2015 Micro Crystal SA
* Alexandre Belloni <[email protected]>
*
*/
#include <linux/bcd.h>
#include <linux/bitops.h>
#include <linux/bitfield.h>
#include <linux/log2.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/rtc.h>
#include <linux/pm_wakeirq.h>
#define RV8803_I2C_TRY_COUNT 4
#define RV8803_SEC 0x00
#define RV8803_MIN 0x01
#define RV8803_HOUR 0x02
#define RV8803_WEEK 0x03
#define RV8803_DAY 0x04
#define RV8803_MONTH 0x05
#define RV8803_YEAR 0x06
#define RV8803_RAM 0x07
#define RV8803_ALARM_MIN 0x08
#define RV8803_ALARM_HOUR 0x09
#define RV8803_ALARM_WEEK_OR_DAY 0x0A
#define RV8803_EXT 0x0D
#define RV8803_FLAG 0x0E
#define RV8803_CTRL 0x0F
#define RV8803_OSC_OFFSET 0x2C
#define RV8803_EXT_WADA BIT(6)
#define RV8803_FLAG_V1F BIT(0)
#define RV8803_FLAG_V2F BIT(1)
#define RV8803_FLAG_AF BIT(3)
#define RV8803_FLAG_TF BIT(4)
#define RV8803_FLAG_UF BIT(5)
#define RV8803_CTRL_RESET BIT(0)
#define RV8803_CTRL_EIE BIT(2)
#define RV8803_CTRL_AIE BIT(3)
#define RV8803_CTRL_TIE BIT(4)
#define RV8803_CTRL_UIE BIT(5)
#define RX8803_CTRL_CSEL GENMASK(7, 6)
#define RX8900_BACKUP_CTRL 0x18
#define RX8900_FLAG_SWOFF BIT(2)
#define RX8900_FLAG_VDETOFF BIT(3)
enum rv8803_type {
rv_8803,
rx_8803,
rx_8804,
rx_8900
};
struct rv8803_data {
struct i2c_client *client;
struct rtc_device *rtc;
struct mutex flags_lock;
u8 ctrl;
u8 backup;
u8 alarm_invalid:1;
enum rv8803_type type;
};
static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
{
int try = RV8803_I2C_TRY_COUNT;
s32 ret;
/*
* There is a 61µs window during which the RTC does not acknowledge I2C
* transfers. In that case, ensure that there are multiple attempts.
*/
do
ret = i2c_smbus_read_byte_data(client, reg);
while ((ret == -ENXIO || ret == -EIO) && --try);
if (ret < 0)
dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
return ret;
}
static int rv8803_read_regs(const struct i2c_client *client,
u8 reg, u8 count, u8 *values)
{
int try = RV8803_I2C_TRY_COUNT;
s32 ret;
do
ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
while ((ret == -ENXIO || ret == -EIO) && --try);
if (ret != count) {
dev_err(&client->dev,
"Unable to read registers 0x%02x..0x%02x\n",
reg, reg + count - 1);
return ret < 0 ? ret : -EIO;
}
return 0;
}
static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
{
int try = RV8803_I2C_TRY_COUNT;
s32 ret;
do
ret = i2c_smbus_write_byte_data(client, reg, value);
while ((ret == -ENXIO || ret == -EIO) && --try);
if (ret)
dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
return ret;
}
static int rv8803_write_regs(const struct i2c_client *client,
u8 reg, u8 count, const u8 *values)
{
int try = RV8803_I2C_TRY_COUNT;
s32 ret;
do
ret = i2c_smbus_write_i2c_block_data(client, reg, count,
values);
while ((ret == -ENXIO || ret == -EIO) && --try);
if (ret)
dev_err(&client->dev,
"Unable to write registers 0x%02x..0x%02x\n",
reg, reg + count - 1);
return ret;
}
static int rv8803_regs_init(struct rv8803_data *rv8803)
{
int ret;
ret = rv8803_write_reg(rv8803->client, RV8803_OSC_OFFSET, 0x00);
if (ret)
return ret;
ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
FIELD_PREP(RX8803_CTRL_CSEL, 1)); /* 2s */
if (ret)
return ret;
ret = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3,
(u8[]){ 0, 0, 0 });
if (ret)
return ret;
return rv8803_write_reg(rv8803->client, RV8803_RAM, 0x00);
}
static int rv8803_regs_configure(struct rv8803_data *rv8803);
static int rv8803_regs_reset(struct rv8803_data *rv8803, bool full)
{
/*
* The RV-8803 resets all registers to POR defaults after voltage-loss,
* the Epson RTCs don't, so we manually reset the remainder here.
*/
if (full || rv8803->type == rx_8803 || rv8803->type == rx_8900) {
int ret = rv8803_regs_init(rv8803);
if (ret)
return ret;
}
return rv8803_regs_configure(rv8803);
}
static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct rv8803_data *rv8803 = i2c_get_clientdata(client);
unsigned long events = 0;
int flags;
mutex_lock(&rv8803->flags_lock);
flags = rv8803_read_reg(client, RV8803_FLAG);
if (flags <= 0) {
mutex_unlock(&rv8803->flags_lock);
return IRQ_NONE;
}
if (flags & RV8803_FLAG_V1F)
dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
if (flags & RV8803_FLAG_V2F)
dev_warn(&client->dev, "Voltage low, data loss detected.\n");
if (flags & RV8803_FLAG_TF) {
flags &= ~RV8803_FLAG_TF;
rv8803->ctrl &= ~RV8803_CTRL_TIE;
events |= RTC_PF;
}
if (flags & RV8803_FLAG_AF) {
flags &= ~RV8803_FLAG_AF;
rv8803->ctrl &= ~RV8803_CTRL_AIE;
events |= RTC_AF;
}
if (flags & RV8803_FLAG_UF) {
flags &= ~RV8803_FLAG_UF;
rv8803->ctrl &= ~RV8803_CTRL_UIE;
events |= RTC_UF;
}
if (events) {
rtc_update_irq(rv8803->rtc, 1, events);
rv8803_write_reg(client, RV8803_FLAG, flags);
rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
}
mutex_unlock(&rv8803->flags_lock);
return IRQ_HANDLED;
}
static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
{
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
u8 date1[7];
u8 date2[7];
u8 *date = date1;
int ret, flags;
if (rv8803->alarm_invalid) {
dev_warn(dev, "Corruption detected, data may be invalid.\n");
return -EINVAL;
}
flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
if (flags < 0)
return flags;
if (flags & RV8803_FLAG_V2F) {
dev_warn(dev, "Voltage low, data is invalid.\n");
return -EINVAL;
}
ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
if (ret)
return ret;
if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
if (ret)
return ret;
if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
date = date2;
}
tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f);
tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
return 0;
}
static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
{
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
u8 date[7];
int ctrl, flags, ret;
ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL);
if (ctrl < 0)
return ctrl;
/* Stop the clock */
ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
ctrl | RV8803_CTRL_RESET);
if (ret)
return ret;
date[RV8803_SEC] = bin2bcd(tm->tm_sec);
date[RV8803_MIN] = bin2bcd(tm->tm_min);
date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
date[RV8803_WEEK] = 1 << (tm->tm_wday);
date[RV8803_DAY] = bin2bcd(tm->tm_mday);
date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
if (ret)
return ret;
/* Restart the clock */
ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
ctrl & ~RV8803_CTRL_RESET);
if (ret)
return ret;
mutex_lock(&rv8803->flags_lock);
flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
if (flags < 0) {
mutex_unlock(&rv8803->flags_lock);
return flags;
}
if ((flags & RV8803_FLAG_V2F) || rv8803->alarm_invalid) {
/*
* If we sense corruption in the alarm registers, but see no
* voltage loss flag, we can't rely on other registers having
* sensible values. Reset them fully.
*/
ret = rv8803_regs_reset(rv8803, rv8803->alarm_invalid);
if (ret) {
mutex_unlock(&rv8803->flags_lock);
return ret;
}
rv8803->alarm_invalid = false;
}
ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F));
mutex_unlock(&rv8803->flags_lock);
return ret;
}
static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
struct i2c_client *client = rv8803->client;
u8 alarmvals[3];
int flags, ret;
ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
if (ret)
return ret;
flags = rv8803_read_reg(client, RV8803_FLAG);
if (flags < 0)
return flags;
alarmvals[0] &= 0x7f;
alarmvals[1] &= 0x3f;
alarmvals[2] &= 0x3f;
if (!bcd_is_valid(alarmvals[0]) ||
!bcd_is_valid(alarmvals[1]) ||
!bcd_is_valid(alarmvals[2]))
goto err_invalid;
alrm->time.tm_sec = 0;
alrm->time.tm_min = bcd2bin(alarmvals[0]);
alrm->time.tm_hour = bcd2bin(alarmvals[1]);
alrm->time.tm_mday = bcd2bin(alarmvals[2]);
alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
if ((unsigned int)alrm->time.tm_mday > 31 ||
(unsigned int)alrm->time.tm_hour >= 24 ||
(unsigned int)alrm->time.tm_min >= 60)
goto err_invalid;
return 0;
err_invalid:
rv8803->alarm_invalid = true;
return -EINVAL;
}
static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct i2c_client *client = to_i2c_client(dev);
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
u8 alarmvals[3];
u8 ctrl[2];
int ret, err;
/* 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);
}
mutex_lock(&rv8803->flags_lock);
ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
if (ret) {
mutex_unlock(&rv8803->flags_lock);
return ret;
}
alarmvals[0] = bin2bcd(alrm->time.tm_min);
alarmvals[1] = bin2bcd(alrm->time.tm_hour);
alarmvals[2] = bin2bcd(alrm->time.tm_mday);
if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
rv8803->ctrl);
if (err) {
mutex_unlock(&rv8803->flags_lock);
return err;
}
}
ctrl[0] &= ~RV8803_FLAG_AF;
err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[0]);
mutex_unlock(&rv8803->flags_lock);
if (err)
return err;
err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
if (err)
return err;
if (alrm->enabled) {
if (rv8803->rtc->uie_rtctimer.enabled)
rv8803->ctrl |= RV8803_CTRL_UIE;
if (rv8803->rtc->aie_timer.enabled)
rv8803->ctrl |= RV8803_CTRL_AIE;
err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
rv8803->ctrl);
if (err)
return err;
}
return 0;
}
static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
int ctrl, flags, err;
ctrl = rv8803->ctrl;
if (enabled) {
if (rv8803->rtc->uie_rtctimer.enabled)
ctrl |= RV8803_CTRL_UIE;
if (rv8803->rtc->aie_timer.enabled)
ctrl |= RV8803_CTRL_AIE;
} else {
if (!rv8803->rtc->uie_rtctimer.enabled)
ctrl &= ~RV8803_CTRL_UIE;
if (!rv8803->rtc->aie_timer.enabled)
ctrl &= ~RV8803_CTRL_AIE;
}
mutex_lock(&rv8803->flags_lock);
flags = rv8803_read_reg(client, RV8803_FLAG);
if (flags < 0) {
mutex_unlock(&rv8803->flags_lock);
return flags;
}
flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
err = rv8803_write_reg(client, RV8803_FLAG, flags);
mutex_unlock(&rv8803->flags_lock);
if (err)
return err;
if (ctrl != rv8803->ctrl) {
rv8803->ctrl = ctrl;
err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
if (err)
return err;
}
return 0;
}
static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct i2c_client *client = to_i2c_client(dev);
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
unsigned int vl = 0;
int flags, ret = 0;
switch (cmd) {
case RTC_VL_READ:
flags = rv8803_read_reg(client, RV8803_FLAG);
if (flags < 0)
return flags;
if (flags & RV8803_FLAG_V1F) {
dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
vl = RTC_VL_ACCURACY_LOW;
}
if (flags & RV8803_FLAG_V2F)
vl |= RTC_VL_DATA_INVALID;
return put_user(vl, (unsigned int __user *)arg);
case RTC_VL_CLR:
mutex_lock(&rv8803->flags_lock);
flags = rv8803_read_reg(client, RV8803_FLAG);
if (flags < 0) {
mutex_unlock(&rv8803->flags_lock);
return flags;
}
flags &= ~RV8803_FLAG_V1F;
ret = rv8803_write_reg(client, RV8803_FLAG, flags);
mutex_unlock(&rv8803->flags_lock);
if (ret)
return ret;
return 0;
default:
return -ENOIOCTLCMD;
}
}
static int rv8803_nvram_write(void *priv, unsigned int offset, void *val,
size_t bytes)
{
return rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val);
}
static int rv8803_nvram_read(void *priv, unsigned int offset,
void *val, size_t bytes)
{
int ret;
ret = rv8803_read_reg(priv, RV8803_RAM);
if (ret < 0)
return ret;
*(u8 *)val = ret;
return 0;
}
static const struct rtc_class_ops rv8803_rtc_ops = {
.read_time = rv8803_get_time,
.set_time = rv8803_set_time,
.ioctl = rv8803_ioctl,
.read_alarm = rv8803_get_alarm,
.set_alarm = rv8803_set_alarm,
.alarm_irq_enable = rv8803_alarm_irq_enable,
};
static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
{
struct i2c_client *client = rv8803->client;
struct device_node *node = client->dev.of_node;
int err;
u8 flags;
if (!node)
return 0;
if (rv8803->type != rx_8900)
return 0;
err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL);
if (err < 0)
return err;
flags = (u8)err;
flags &= ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF);
flags |= rv8803->backup;
return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL,
flags);
}
/* configure registers with values different than the Power-On reset defaults */
static int rv8803_regs_configure(struct rv8803_data *rv8803)
{
int err;
err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
if (err)
return err;
err = rx8900_trickle_charger_init(rv8803);
if (err) {
dev_err(&rv8803->client->dev, "failed to init charger\n");
return err;
}
return 0;
}
static int rv8803_resume(struct device *dev)
{
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
if (rv8803->client->irq > 0 && device_may_wakeup(dev))
disable_irq_wake(rv8803->client->irq);
return 0;
}
static int rv8803_suspend(struct device *dev)
{
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
if (rv8803->client->irq > 0 && device_may_wakeup(dev))
enable_irq_wake(rv8803->client->irq);
return 0;
}
static DEFINE_SIMPLE_DEV_PM_OPS(rv8803_pm_ops, rv8803_suspend, rv8803_resume);
static const struct i2c_device_id rv8803_id[] = {
{ "rv8803", rv_8803 },
{ "rv8804", rx_8804 },
{ "rx8803", rx_8803 },
{ "rx8900", rx_8900 },
{ }
};
MODULE_DEVICE_TABLE(i2c, rv8803_id);
static int rv8803_probe(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
struct rv8803_data *rv8803;
int err, flags;
struct nvmem_config nvmem_cfg = {
.name = "rv8803_nvram",
.word_size = 1,
.stride = 1,
.size = 1,
.reg_read = rv8803_nvram_read,
.reg_write = rv8803_nvram_write,
.priv = client,
};
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_I2C_BLOCK)) {
dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
return -EIO;
}
rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
GFP_KERNEL);
if (!rv8803)
return -ENOMEM;
mutex_init(&rv8803->flags_lock);
rv8803->client = client;
if (client->dev.of_node) {
rv8803->type = (uintptr_t)of_device_get_match_data(&client->dev);
} else {
const struct i2c_device_id *id = i2c_match_id(rv8803_id, client);
rv8803->type = id->driver_data;
}
i2c_set_clientdata(client, rv8803);
flags = rv8803_read_reg(client, RV8803_FLAG);
if (flags < 0)
return flags;
if (flags & RV8803_FLAG_V1F)
dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
if (flags & RV8803_FLAG_V2F)
dev_warn(&client->dev, "Voltage low, data loss detected.\n");
if (flags & RV8803_FLAG_AF)
dev_warn(&client->dev, "An alarm maybe have been missed.\n");
rv8803->rtc = devm_rtc_allocate_device(&client->dev);
if (IS_ERR(rv8803->rtc))
return PTR_ERR(rv8803->rtc);
if (client->irq > 0) {
unsigned long irqflags = IRQF_TRIGGER_LOW;
if (dev_fwnode(&client->dev))
irqflags = 0;
err = devm_request_threaded_irq(&client->dev, client->irq,
NULL, rv8803_handle_irq,
irqflags | IRQF_ONESHOT,
"rv8803", client);
if (err) {
dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
client->irq = 0;
} else {
device_init_wakeup(&client->dev, true);
err = dev_pm_set_wake_irq(&client->dev, client->irq);
if (err)
dev_err(&client->dev, "failed to set wake IRQ\n");
}
} else {
if (device_property_read_bool(&client->dev, "wakeup-source"))
device_init_wakeup(&client->dev, true);
else
clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features);
}
if (of_property_read_bool(client->dev.of_node, "epson,vdet-disable"))
rv8803->backup |= RX8900_FLAG_VDETOFF;
if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
rv8803->backup |= RX8900_FLAG_SWOFF;
err = rv8803_regs_configure(rv8803);
if (err)
return err;
rv8803->rtc->ops = &rv8803_rtc_ops;
rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099;
err = devm_rtc_register_device(rv8803->rtc);
if (err)
return err;
devm_rtc_nvmem_register(rv8803->rtc, &nvmem_cfg);
rv8803->rtc->max_user_freq = 1;
return 0;
}
static const __maybe_unused struct of_device_id rv8803_of_match[] = {
{
.compatible = "microcrystal,rv8803",
.data = (void *)rv_8803
},
{
.compatible = "epson,rx8803",
.data = (void *)rx_8803
},
{
.compatible = "epson,rx8804",
.data = (void *)rx_8804
},
{
.compatible = "epson,rx8900",
.data = (void *)rx_8900
},
{ }
};
MODULE_DEVICE_TABLE(of, rv8803_of_match);
static struct i2c_driver rv8803_driver = {
.driver = {
.name = "rtc-rv8803",
.of_match_table = of_match_ptr(rv8803_of_match),
.pm = &rv8803_pm_ops,
},
.probe = rv8803_probe,
.id_table = rv8803_id,
};
module_i2c_driver(rv8803_driver);
MODULE_AUTHOR("Alexandre Belloni <[email protected]>");
MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
MODULE_LICENSE("GPL v2");
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