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/*
* RTC driver for the Micro Crystal RV8803
*
* Copyright (C) 2015 Micro Crystal SA
*
* Alexandre Belloni <alexandre.belloni@free-electrons.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/bcd.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtc.h>
#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_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)
struct rv8803_data {
struct i2c_client *client;
struct rtc_device *rtc;
struct mutex flags_lock;
u8 ctrl;
};
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, try = 0;
mutex_lock(&rv8803->flags_lock);
do {
flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
try++;
} while ((flags == -ENXIO) && (try < 3));
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);
i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
i2c_smbus_write_byte_data(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;
flags = i2c_smbus_read_byte_data(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 = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
7, date);
if (ret != 7)
return ret < 0 ? ret : -EIO;
if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
7, date2);
if (ret != 7)
return ret < 0 ? ret : -EIO;
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 = ffs(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 rtc_valid_tm(tm);
}
static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
{
struct rv8803_data *rv8803 = dev_get_drvdata(dev);
u8 date[7];
int flags, ret;
if ((tm->tm_year < 100) || (tm->tm_year > 199))
return -EINVAL;
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 = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
7, date);
if (ret < 0)
return ret;
mutex_lock(&rv8803->flags_lock);
flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
if (flags < 0) {
mutex_unlock(&rv8803->flags_lock);
return flags;
}
ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
flags & ~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 = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
3, alarmvals);
if (ret != 3)
return ret < 0 ? ret : -EIO;
flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
if (flags < 0)
return flags;
alrm->time.tm_sec = 0;
alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
alrm->time.tm_wday = -1;
alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
alrm->time.tm_mon = -1;
alrm->time.tm_year = -1;
alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
return 0;
}
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 = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
if (ret != 2) {
mutex_unlock(&rv8803->flags_lock);
return ret < 0 ? ret : -EIO;
}
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 = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
rv8803->ctrl);
if (err) {
mutex_unlock(&rv8803->flags_lock);
return err;
}
}
ctrl[1] &= ~RV8803_FLAG_AF;
err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
mutex_unlock(&rv8803->flags_lock);
if (err)
return err;
err = i2c_smbus_write_i2c_block_data(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 = i2c_smbus_write_byte_data(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 = i2c_smbus_read_byte_data(client, RV8803_FLAG);
if (flags < 0) {
mutex_unlock(&rv8803->flags_lock);
return flags;
}
flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
mutex_unlock(&rv8803->flags_lock);
if (err)
return err;
if (ctrl != rv8803->ctrl) {
rv8803->ctrl = ctrl;
err = i2c_smbus_write_byte_data(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);
int flags, ret = 0;
switch (cmd) {
case RTC_VL_READ:
flags = i2c_smbus_read_byte_data(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");
flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
return -EFAULT;
return 0;
case RTC_VL_CLR:
mutex_lock(&rv8803->flags_lock);
flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
if (flags < 0) {
mutex_unlock(&rv8803->flags_lock);
return flags;
}
flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
mutex_unlock(&rv8803->flags_lock);
if (ret < 0)
return ret;
return 0;
default:
return -ENOIOCTLCMD;
}
}
static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct i2c_client *client = to_i2c_client(dev);
int ret;
ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
if (ret < 0)
return ret;
return 1;
}
static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct device *dev = kobj_to_dev(kobj);
struct i2c_client *client = to_i2c_client(dev);
int ret;
ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
if (ret < 0)
return ret;
buf[0] = ret;
return 1;
}
static struct bin_attribute rv8803_nvram_attr = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.size = 1,
.read = rv8803_nvram_read,
.write = rv8803_nvram_write,
};
static struct rtc_class_ops rv8803_rtc_ops = {
.read_time = rv8803_get_time,
.set_time = rv8803_set_time,
.ioctl = rv8803_ioctl,
};
static int rv8803_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
struct rv8803_data *rv8803;
int err, flags, try = 0;
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;
i2c_set_clientdata(client, rv8803);
/*
* There is a 60┬Ás window where the RTC may not reply on the i2c bus in
* that case, the transfer is not ACKed. In that case, ensure there are
* multiple attempts.
*/
do {
flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
try++;
} while ((flags == -ENXIO) && (try < 3));
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");
if (client->irq > 0) {
err = devm_request_threaded_irq(&client->dev, client->irq,
NULL, rv8803_handle_irq,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
"rv8803", client);
if (err) {
dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
client->irq = 0;
} else {
rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
}
}
rv8803->rtc = devm_rtc_device_register(&client->dev, client->name,
&rv8803_rtc_ops, THIS_MODULE);
if (IS_ERR(rv8803->rtc)) {
dev_err(&client->dev, "unable to register the class device\n");
return PTR_ERR(rv8803->rtc);
}
try = 0;
do {
err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
RV8803_EXT_WADA);
try++;
} while ((err == -ENXIO) && (try < 3));
if (err)
return err;
err = device_create_bin_file(&client->dev, &rv8803_nvram_attr);
if (err)
return err;
rv8803->rtc->max_user_freq = 1;
return 0;
}
static int rv8803_remove(struct i2c_client *client)
{
device_remove_bin_file(&client->dev, &rv8803_nvram_attr);
return 0;
}
static const struct i2c_device_id rv8803_id[] = {
{ "rv8803", 0 },
{ "rx8900", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, rv8803_id);
static struct i2c_driver rv8803_driver = {
.driver = {
.name = "rtc-rv8803",
},
.probe = rv8803_probe,
.remove = rv8803_remove,
.id_table = rv8803_id,
};
module_i2c_driver(rv8803_driver);
MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
MODULE_LICENSE("GPL v2");