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linux/drivers/rtc/rtc-rx8025.c
Mathew McBride 71af915650 rtc: rx8025: fix 12/24 hour mode detection on RX-8035 
The 12/24hr flag in the RX-8035 can be found in the hour register,
instead of the CTRL1 on the RX-8025. This was overlooked when
support for the RX-8035 was added, and was causing read errors when
the hour register 'overflowed'.

To deal with the relevant register not always being visible in
the relevant functions, determine the 12/24 mode at startup and
store it in the driver state.

Signed-off-by: Mathew McBride <matt@traverse.com.au>
Fixes: f120e2e33a ("rtc: rx8025: implement RX-8035 support")
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220706074236.24011-1-matt@traverse.com.au
2022-07-26 16:49:45 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Epson's RTC module RX-8025 SA/NB
*
* Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
*
* Copyright (C) 2005 by Digi International Inc.
* All rights reserved.
*
* Modified by fengjh at rising.com.cn
* <lm-sensors@lm-sensors.org>
* 2006.11
*
* Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
* Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
* Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
*/
#include <linux/bcd.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtc.h>
/* Register definitions */
#define RX8025_REG_SEC 0x00
#define RX8025_REG_MIN 0x01
#define RX8025_REG_HOUR 0x02
#define RX8025_REG_WDAY 0x03
#define RX8025_REG_MDAY 0x04
#define RX8025_REG_MONTH 0x05
#define RX8025_REG_YEAR 0x06
#define RX8025_REG_DIGOFF 0x07
#define RX8025_REG_ALWMIN 0x08
#define RX8025_REG_ALWHOUR 0x09
#define RX8025_REG_ALWWDAY 0x0a
#define RX8025_REG_ALDMIN 0x0b
#define RX8025_REG_ALDHOUR 0x0c
/* 0x0d is reserved */
#define RX8025_REG_CTRL1 0x0e
#define RX8025_REG_CTRL2 0x0f
#define RX8025_BIT_CTRL1_CT (7 << 0)
/* 1 Hz periodic level irq */
#define RX8025_BIT_CTRL1_CT_1HZ 4
#define RX8025_BIT_CTRL1_TEST BIT(3)
#define RX8025_BIT_CTRL1_1224 BIT(5)
#define RX8025_BIT_CTRL1_DALE BIT(6)
#define RX8025_BIT_CTRL1_WALE BIT(7)
#define RX8025_BIT_CTRL2_DAFG BIT(0)
#define RX8025_BIT_CTRL2_WAFG BIT(1)
#define RX8025_BIT_CTRL2_CTFG BIT(2)
#define RX8025_BIT_CTRL2_PON BIT(4)
#define RX8025_BIT_CTRL2_XST BIT(5)
#define RX8025_BIT_CTRL2_VDET BIT(6)
#define RX8035_BIT_HOUR_1224 BIT(7)
/* Clock precision adjustment */
#define RX8025_ADJ_RESOLUTION 3050 /* in ppb */
#define RX8025_ADJ_DATA_MAX 62
#define RX8025_ADJ_DATA_MIN -62
enum rx_model {
model_rx_unknown,
model_rx_8025,
model_rx_8035,
model_last
};
static const struct i2c_device_id rx8025_id[] = {
{ "rx8025", model_rx_8025 },
{ "rx8035", model_rx_8035 },
{ }
};
MODULE_DEVICE_TABLE(i2c, rx8025_id);
struct rx8025_data {
struct rtc_device *rtc;
enum rx_model model;
u8 ctrl1;
int is_24;
};
static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
{
return i2c_smbus_read_byte_data(client, number << 4);
}
static int rx8025_read_regs(const struct i2c_client *client,
u8 number, u8 length, u8 *values)
{
int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
values);
if (ret != length)
return ret < 0 ? ret : -EIO;
return 0;
}
static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
u8 value)
{
return i2c_smbus_write_byte_data(client, number << 4, value);
}
static s32 rx8025_write_regs(const struct i2c_client *client,
u8 number, u8 length, const u8 *values)
{
return i2c_smbus_write_i2c_block_data(client, number << 4,
length, values);
}
static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
{
int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
/* XSTP bit has different polarity on RX-8025 vs RX-8035.
* RX-8025: 0 == oscillator stopped
* RX-8035: 1 == oscillator stopped
*/
if (model == model_rx_8025)
xstp = !xstp;
return xstp;
}
static int rx8025_check_validity(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct rx8025_data *drvdata = dev_get_drvdata(dev);
int ctrl2;
int xstp;
ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
if (ctrl2 < 0)
return ctrl2;
if (ctrl2 & RX8025_BIT_CTRL2_VDET)
dev_warn(dev, "power voltage drop detected\n");
if (ctrl2 & RX8025_BIT_CTRL2_PON) {
dev_warn(dev, "power-on reset detected, date is invalid\n");
return -EINVAL;
}
xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
if (xstp) {
dev_warn(dev, "crystal stopped, date is invalid\n");
return -EINVAL;
}
return 0;
}
static int rx8025_reset_validity(struct i2c_client *client)
{
struct rx8025_data *drvdata = i2c_get_clientdata(client);
int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
if (ctrl2 < 0)
return ctrl2;
ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
if (drvdata->model == model_rx_8025)
ctrl2 |= RX8025_BIT_CTRL2_XST;
else
ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
return rx8025_write_reg(client, RX8025_REG_CTRL2,
ctrl2);
}
static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct rx8025_data *rx8025 = i2c_get_clientdata(client);
int status, xstp;
rtc_lock(rx8025->rtc);
status = rx8025_read_reg(client, RX8025_REG_CTRL2);
if (status < 0)
goto out;
xstp = rx8025_is_osc_stopped(rx8025->model, status);
if (xstp)
dev_warn(&client->dev, "Oscillation stop was detected,"
"you may have to readjust the clock\n");
if (status & RX8025_BIT_CTRL2_CTFG) {
/* periodic */
status &= ~RX8025_BIT_CTRL2_CTFG;
rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
}
if (status & RX8025_BIT_CTRL2_DAFG) {
/* alarm */
status &= RX8025_BIT_CTRL2_DAFG;
if (rx8025_write_reg(client, RX8025_REG_CTRL1,
rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
goto out;
rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
}
out:
rtc_unlock(rx8025->rtc);
return IRQ_HANDLED;
}
static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
{
struct i2c_client *client = to_i2c_client(dev);
struct rx8025_data *rx8025 = dev_get_drvdata(dev);
u8 date[7];
int err;
err = rx8025_check_validity(dev);
if (err)
return err;
err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
if (err)
return err;
dev_dbg(dev, "%s: read %7ph\n", __func__, date);
dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
if (rx8025->is_24)
dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
else
dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
+ (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
return 0;
}
static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
{
struct i2c_client *client = to_i2c_client(dev);
struct rx8025_data *rx8025 = dev_get_drvdata(dev);
u8 date[7];
int ret;
/*
* Here the read-only bits are written as "0". I'm not sure if that
* is sound.
*/
date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
if (rx8025->is_24)
date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
else
date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
| bin2bcd((dt->tm_hour + 11) % 12 + 1);
date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
dev_dbg(dev, "%s: write %7ph\n", __func__, date);
ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
if (ret < 0)
return ret;
return rx8025_reset_validity(client);
}
static int rx8025_init_client(struct i2c_client *client)
{
struct rx8025_data *rx8025 = i2c_get_clientdata(client);
u8 ctrl[2], ctrl2;
int need_clear = 0;
int hour_reg;
int err;
err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
if (err)
goto out;
/* Keep test bit zero ! */
rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
dev_warn(&client->dev, "Alarm was detected\n");
need_clear = 1;
}
if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
need_clear = 1;
if (need_clear) {
ctrl2 = ctrl[1];
ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
RX8025_BIT_CTRL2_DAFG);
err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
}
if (rx8025->model == model_rx_8035) {
/* In RX-8035, 12/24 flag is in the hour register */
hour_reg = rx8025_read_reg(client, RX8025_REG_HOUR);
if (hour_reg < 0)
return hour_reg;
rx8025->is_24 = (hour_reg & RX8035_BIT_HOUR_1224);
} else {
rx8025->is_24 = (ctrl[1] & RX8025_BIT_CTRL1_1224);
}
out:
return err;
}
/* Alarm support */
static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct rx8025_data *rx8025 = dev_get_drvdata(dev);
u8 ald[2];
int ctrl2, err;
err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
if (err)
return err;
ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
if (ctrl2 < 0)
return ctrl2;
dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
__func__, ald[0], ald[1], ctrl2);
/* Hardware alarms precision is 1 minute! */
t->time.tm_sec = 0;
t->time.tm_min = bcd2bin(ald[0] & 0x7f);
if (rx8025->is_24)
t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
else
t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
+ (ald[1] & 0x20 ? 12 : 0);
dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
return err;
}
static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct rx8025_data *rx8025 = dev_get_drvdata(dev);
u8 ald[2];
int err;
ald[0] = bin2bcd(t->time.tm_min);
if (rx8025->is_24)
ald[1] = bin2bcd(t->time.tm_hour);
else
ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
| bin2bcd((t->time.tm_hour + 11) % 12 + 1);
dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
err = rx8025_write_reg(client, RX8025_REG_CTRL1,
rx8025->ctrl1);
if (err)
return err;
}
err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
if (err)
return err;
if (t->enabled) {
rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
err = rx8025_write_reg(client, RX8025_REG_CTRL1,
rx8025->ctrl1);
if (err)
return err;
}
return 0;
}
static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct rx8025_data *rx8025 = dev_get_drvdata(dev);
u8 ctrl1;
int err;
ctrl1 = rx8025->ctrl1;
if (enabled)
ctrl1 |= RX8025_BIT_CTRL1_DALE;
else
ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
if (ctrl1 != rx8025->ctrl1) {
rx8025->ctrl1 = ctrl1;
err = rx8025_write_reg(client, RX8025_REG_CTRL1,
rx8025->ctrl1);
if (err)
return err;
}
return 0;
}
/*
* According to the RX8025 SA/NB application manual the frequency and
* temperature characteristics can be approximated using the following
* equation:
*
* df = a * (ut - t)**2
*
* df: Frequency deviation in any temperature
* a : Coefficient = (-35 +-5) * 10**-9
* ut: Ultimate temperature in degree = +25 +-5 degree
* t : Any temperature in degree
*/
static int rx8025_read_offset(struct device *dev, long *offset)
{
struct i2c_client *client = to_i2c_client(dev);
int digoff;
digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
if (digoff < 0)
return digoff;
*offset = digoff >= 64 ? digoff - 128 : digoff;
if (*offset > 0)
(*offset)--;
*offset *= RX8025_ADJ_RESOLUTION;
return 0;
}
static int rx8025_set_offset(struct device *dev, long offset)
{
struct i2c_client *client = to_i2c_client(dev);
u8 digoff;
offset /= RX8025_ADJ_RESOLUTION;
if (offset > RX8025_ADJ_DATA_MAX)
offset = RX8025_ADJ_DATA_MAX;
else if (offset < RX8025_ADJ_DATA_MIN)
offset = RX8025_ADJ_DATA_MIN;
else if (offset > 0)
offset++;
else if (offset < 0)
offset += 128;
digoff = offset;
return rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
}
static const struct rtc_class_ops rx8025_rtc_ops = {
.read_time = rx8025_get_time,
.set_time = rx8025_set_time,
.read_alarm = rx8025_read_alarm,
.set_alarm = rx8025_set_alarm,
.alarm_irq_enable = rx8025_alarm_irq_enable,
.read_offset = rx8025_read_offset,
.set_offset = rx8025_set_offset,
};
static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
struct device_attribute *attr,
char *buf)
{
long adj;
int err;
dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
err = rx8025_read_offset(dev, &adj);
if (err)
return err;
return sprintf(buf, "%ld\n", -adj);
}
static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
long adj;
int err;
dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
if (kstrtol(buf, 10, &adj) != 0)
return -EINVAL;
err = rx8025_set_offset(dev, -adj);
return err ? err : count;
}
static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
rx8025_sysfs_show_clock_adjust,
rx8025_sysfs_store_clock_adjust);
static struct attribute *rx8025_attrs[] = {
&dev_attr_clock_adjust_ppb.attr,
NULL
};
static const struct attribute_group rx8025_attr_group = {
.attrs = rx8025_attrs,
};
static int rx8025_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct rx8025_data *rx8025;
int err = 0;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
| I2C_FUNC_SMBUS_I2C_BLOCK)) {
dev_err(&adapter->dev,
"doesn't support required functionality\n");
return -EIO;
}
rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
if (!rx8025)
return -ENOMEM;
i2c_set_clientdata(client, rx8025);
if (id)
rx8025->model = id->driver_data;
err = rx8025_init_client(client);
if (err)
return err;
rx8025->rtc = devm_rtc_allocate_device(&client->dev);
if (IS_ERR(rx8025->rtc))
return PTR_ERR(rx8025->rtc);
rx8025->rtc->ops = &rx8025_rtc_ops;
rx8025->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
rx8025->rtc->range_max = RTC_TIMESTAMP_END_2099;
if (client->irq > 0) {
dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
rx8025_handle_irq,
IRQF_ONESHOT,
"rx8025", client);
if (err)
clear_bit(RTC_FEATURE_ALARM, rx8025->rtc->features);
}
rx8025->rtc->max_user_freq = 1;
set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rx8025->rtc->features);
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rx8025->rtc->features);
err = rtc_add_group(rx8025->rtc, &rx8025_attr_group);
if (err)
return err;
return devm_rtc_register_device(rx8025->rtc);
}
static struct i2c_driver rx8025_driver = {
.driver = {
.name = "rtc-rx8025",
},
.probe = rx8025_probe,
.id_table = rx8025_id,
};
module_i2c_driver(rx8025_driver);
MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
MODULE_LICENSE("GPL");
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