linux/drivers/rtc/rtc-rx8025.c
Alexandre Belloni b476266f06 rtc: rx8025: use .set_offset/.read_offset
The driver has its own sysfs file to adjust the clock. Fortunately, it is
already in pbb, however, the sign it expects is the opposite of what the
RTC core does (which actually aligns with the RTC).

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211107225458.111068-12-alexandre.belloni@bootlin.com
2021-11-10 00:45:57 +01:00

583 lines
14 KiB
C

// 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)
/* 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;
};
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->ctrl1 & RX8025_BIT_CTRL1_1224)
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->ctrl1 & RX8025_BIT_CTRL1_1224)
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 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);
}
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->ctrl1 & RX8025_BIT_CTRL1_1224)
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->ctrl1 & RX8025_BIT_CTRL1_1224)
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;
int err;
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;
err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
if (err)
return err;
return 0;
}
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");