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linux-next/drivers/rtc/rtc-ab-eoz9.c
Maxime Chevallier e0779a0dcf rtc: ab-eoz9: don't fail temperature reads on undervoltage notification 
The undervoltage flags reported by the RTC are useful to know if the
time and date are reliable after a reboot. Although the threshold VLOW1
indicates that the thermometer has been shutdown and time compensation
is off, it doesn't mean that the temperature readout is currently
impossible.

As the system is running, the RTC voltage is now fully established and
we can read the temperature.

Fixes: 67075b63cc ("rtc: add AB-RTCMC-32.768kHz-EOZ9 RTC support")
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://lore.kernel.org/r/20241122101031.68916-3-maxime.chevallier@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2024-11-25 23:34:12 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Real Time Clock driver for AB-RTCMC-32.768kHz-EOZ9 chip.
* Copyright (C) 2019 Orolia
*
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/bitfield.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#define ABEOZ9_REG_CTRL1 0x00
#define ABEOZ9_REG_CTRL1_MASK GENMASK(7, 0)
#define ABEOZ9_REG_CTRL1_WE BIT(0)
#define ABEOZ9_REG_CTRL1_TE BIT(1)
#define ABEOZ9_REG_CTRL1_TAR BIT(2)
#define ABEOZ9_REG_CTRL1_EERE BIT(3)
#define ABEOZ9_REG_CTRL1_SRON BIT(4)
#define ABEOZ9_REG_CTRL1_TD0 BIT(5)
#define ABEOZ9_REG_CTRL1_TD1 BIT(6)
#define ABEOZ9_REG_CTRL1_CLKINT BIT(7)
#define ABEOZ9_REG_CTRL_INT 0x01
#define ABEOZ9_REG_CTRL_INT_AIE BIT(0)
#define ABEOZ9_REG_CTRL_INT_TIE BIT(1)
#define ABEOZ9_REG_CTRL_INT_V1IE BIT(2)
#define ABEOZ9_REG_CTRL_INT_V2IE BIT(3)
#define ABEOZ9_REG_CTRL_INT_SRIE BIT(4)
#define ABEOZ9_REG_CTRL_INT_FLAG 0x02
#define ABEOZ9_REG_CTRL_INT_FLAG_AF BIT(0)
#define ABEOZ9_REG_CTRL_INT_FLAG_TF BIT(1)
#define ABEOZ9_REG_CTRL_INT_FLAG_V1IF BIT(2)
#define ABEOZ9_REG_CTRL_INT_FLAG_V2IF BIT(3)
#define ABEOZ9_REG_CTRL_INT_FLAG_SRF BIT(4)
#define ABEOZ9_REG_CTRL_STATUS 0x03
#define ABEOZ9_REG_CTRL_STATUS_V1F BIT(2)
#define ABEOZ9_REG_CTRL_STATUS_V2F BIT(3)
#define ABEOZ9_REG_CTRL_STATUS_SR BIT(4)
#define ABEOZ9_REG_CTRL_STATUS_PON BIT(5)
#define ABEOZ9_REG_CTRL_STATUS_EEBUSY BIT(7)
#define ABEOZ9_REG_SEC 0x08
#define ABEOZ9_REG_MIN 0x09
#define ABEOZ9_REG_HOURS 0x0A
#define ABEOZ9_HOURS_PM BIT(6)
#define ABEOZ9_REG_DAYS 0x0B
#define ABEOZ9_REG_WEEKDAYS 0x0C
#define ABEOZ9_REG_MONTHS 0x0D
#define ABEOZ9_REG_YEARS 0x0E
#define ABEOZ9_SEC_LEN 7
#define ABEOZ9_REG_ALARM_SEC 0x10
#define ABEOZ9_BIT_ALARM_SEC GENMASK(6, 0)
#define ABEOZ9_REG_ALARM_MIN 0x11
#define ABEOZ9_BIT_ALARM_MIN GENMASK(6, 0)
#define ABEOZ9_REG_ALARM_HOURS 0x12
#define ABEOZ9_BIT_ALARM_HOURS_PM BIT(5)
#define ABEOZ9_BIT_ALARM_HOURS GENMASK(5, 0)
#define ABEOZ9_REG_ALARM_DAYS 0x13
#define ABEOZ9_BIT_ALARM_DAYS GENMASK(5, 0)
#define ABEOZ9_REG_ALARM_WEEKDAYS 0x14
#define ABEOZ9_BIT_ALARM_WEEKDAYS GENMASK(2, 0)
#define ABEOZ9_REG_ALARM_MONTHS 0x15
#define ABEOZ9_BIT_ALARM_MONTHS GENMASK(4, 0)
#define ABEOZ9_REG_ALARM_YEARS 0x16
#define ABEOZ9_ALARM_LEN 7
#define ABEOZ9_BIT_ALARM_AE BIT(7)
#define ABEOZ9_REG_REG_TEMP 0x20
#define ABEOZ953_TEMP_MAX 120
#define ABEOZ953_TEMP_MIN -60
#define ABEOZ9_REG_EEPROM 0x30
#define ABEOZ9_REG_EEPROM_MASK GENMASK(8, 0)
#define ABEOZ9_REG_EEPROM_THP BIT(0)
#define ABEOZ9_REG_EEPROM_THE BIT(1)
#define ABEOZ9_REG_EEPROM_FD0 BIT(2)
#define ABEOZ9_REG_EEPROM_FD1 BIT(3)
#define ABEOZ9_REG_EEPROM_R1K BIT(4)
#define ABEOZ9_REG_EEPROM_R5K BIT(5)
#define ABEOZ9_REG_EEPROM_R20K BIT(6)
#define ABEOZ9_REG_EEPROM_R80K BIT(7)
struct abeoz9_rtc_data {
struct rtc_device *rtc;
struct regmap *regmap;
struct device *hwmon_dev;
};
static int abeoz9_check_validity(struct device *dev)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
int ret;
int val;
ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
if (ret < 0) {
dev_err(dev,
"unable to get CTRL_STATUS register (%d)\n", ret);
return ret;
}
if (val & ABEOZ9_REG_CTRL_STATUS_PON) {
dev_warn(dev, "power-on reset detected, date is invalid\n");
return -EINVAL;
}
if (val & ABEOZ9_REG_CTRL_STATUS_V1F) {
dev_warn(dev,
"voltage drops below VLOW1 threshold, date is invalid\n");
return -EINVAL;
}
if ((val & ABEOZ9_REG_CTRL_STATUS_V2F)) {
dev_warn(dev,
"voltage drops below VLOW2 threshold, date is invalid\n");
return -EINVAL;
}
return 0;
}
static int abeoz9_reset_validity(struct regmap *regmap)
{
return regmap_update_bits(regmap, ABEOZ9_REG_CTRL_STATUS,
ABEOZ9_REG_CTRL_STATUS_V1F |
ABEOZ9_REG_CTRL_STATUS_V2F |
ABEOZ9_REG_CTRL_STATUS_PON,
0);
}
static int abeoz9_rtc_get_time(struct device *dev, struct rtc_time *tm)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
u8 regs[ABEOZ9_SEC_LEN];
int ret;
ret = abeoz9_check_validity(dev);
if (ret)
return ret;
ret = regmap_bulk_read(data->regmap, ABEOZ9_REG_SEC,
regs,
sizeof(regs));
if (ret) {
dev_err(dev, "reading RTC time failed (%d)\n", ret);
return ret;
}
tm->tm_sec = bcd2bin(regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] & 0x7F);
tm->tm_min = bcd2bin(regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] & 0x7F);
if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM) {
tm->tm_hour =
bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & 0x1f);
if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM)
tm->tm_hour += 12;
} else {
tm->tm_hour = bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC]);
}
tm->tm_mday = bcd2bin(regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC]);
tm->tm_wday = bcd2bin(regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC]);
tm->tm_mon = bcd2bin(regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC]) - 1;
tm->tm_year = bcd2bin(regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC]) + 100;
return ret;
}
static int abeoz9_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
u8 regs[ABEOZ9_SEC_LEN];
int ret;
regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_sec);
regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_min);
regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_hour);
regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mday);
regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_wday);
regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mon + 1);
regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_year - 100);
ret = regmap_bulk_write(data->regmap, ABEOZ9_REG_SEC,
regs,
sizeof(regs));
if (ret) {
dev_err(dev, "set RTC time failed (%d)\n", ret);
return ret;
}
return abeoz9_reset_validity(regmap);
}
static int abeoz9_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
u8 regs[ABEOZ9_ALARM_LEN];
u8 val[2];
int ret;
ret = abeoz9_check_validity(dev);
if (ret)
return ret;
ret = regmap_bulk_read(regmap, ABEOZ9_REG_CTRL_INT, val, sizeof(val));
if (ret)
return ret;
alarm->enabled = val[0] & ABEOZ9_REG_CTRL_INT_AIE;
alarm->pending = val[1] & ABEOZ9_REG_CTRL_INT_FLAG_AF;
ret = regmap_bulk_read(regmap, ABEOZ9_REG_ALARM_SEC, regs, sizeof(regs));
if (ret)
return ret;
alarm->time.tm_sec = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_SEC, regs[0]));
alarm->time.tm_min = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_MIN, regs[1]));
alarm->time.tm_hour = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_HOURS, regs[2]));
alarm->time.tm_mday = bcd2bin(FIELD_GET(ABEOZ9_BIT_ALARM_DAYS, regs[3]));
return 0;
}
static int abeoz9_rtc_alarm_irq_enable(struct device *dev, u32 enable)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
return regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT,
ABEOZ9_REG_CTRL_INT_AIE,
FIELD_PREP(ABEOZ9_REG_CTRL_INT_AIE, enable));
}
static int abeoz9_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
u8 regs[ABEOZ9_ALARM_LEN] = {0};
int ret;
ret = regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG,
ABEOZ9_REG_CTRL_INT_FLAG_AF, 0);
if (ret)
return ret;
regs[0] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_SEC,
bin2bcd(alarm->time.tm_sec));
regs[1] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_MIN,
bin2bcd(alarm->time.tm_min));
regs[2] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_HOURS,
bin2bcd(alarm->time.tm_hour));
regs[3] = ABEOZ9_BIT_ALARM_AE | FIELD_PREP(ABEOZ9_BIT_ALARM_DAYS,
bin2bcd(alarm->time.tm_mday));
ret = regmap_bulk_write(data->regmap, ABEOZ9_REG_ALARM_SEC, regs,
sizeof(regs));
if (ret)
return ret;
return abeoz9_rtc_alarm_irq_enable(dev, alarm->enabled);
}
static irqreturn_t abeoz9_rtc_irq(int irq, void *dev)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
unsigned int val;
int ret;
ret = regmap_read(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG, &val);
if (ret)
return IRQ_NONE;
if (!FIELD_GET(ABEOZ9_REG_CTRL_INT_FLAG_AF, val))
return IRQ_NONE;
regmap_update_bits(data->regmap, ABEOZ9_REG_CTRL_INT_FLAG,
ABEOZ9_REG_CTRL_INT_FLAG_AF, 0);
rtc_update_irq(data->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int abeoz9_trickle_parse_dt(struct device_node *node)
{
u32 ohms = 0;
if (of_property_read_u32(node, "trickle-resistor-ohms", &ohms))
return 0;
switch (ohms) {
case 1000:
return ABEOZ9_REG_EEPROM_R1K;
case 5000:
return ABEOZ9_REG_EEPROM_R5K;
case 20000:
return ABEOZ9_REG_EEPROM_R20K;
case 80000:
return ABEOZ9_REG_EEPROM_R80K;
default:
return 0;
}
}
static int abeoz9_rtc_setup(struct device *dev, struct device_node *node)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
int ret;
/* Enable Self Recovery, Clock for Watch and EEPROM refresh functions */
ret = regmap_update_bits(regmap, ABEOZ9_REG_CTRL1,
ABEOZ9_REG_CTRL1_MASK,
ABEOZ9_REG_CTRL1_WE |
ABEOZ9_REG_CTRL1_EERE |
ABEOZ9_REG_CTRL1_SRON);
if (ret < 0) {
dev_err(dev, "unable to set CTRL_1 register (%d)\n", ret);
return ret;
}
ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT, 0);
if (ret < 0) {
dev_err(dev,
"unable to set control CTRL_INT register (%d)\n",
ret);
return ret;
}
ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT_FLAG, 0);
if (ret < 0) {
dev_err(dev,
"unable to set control CTRL_INT_FLAG register (%d)\n",
ret);
return ret;
}
ret = abeoz9_trickle_parse_dt(node);
/* Enable built-in termometer */
ret |= ABEOZ9_REG_EEPROM_THE;
ret = regmap_update_bits(regmap, ABEOZ9_REG_EEPROM,
ABEOZ9_REG_EEPROM_MASK,
ret);
if (ret < 0) {
dev_err(dev, "unable to set EEPROM register (%d)\n", ret);
return ret;
}
return ret;
}
static const struct rtc_class_ops rtc_ops = {
.read_time = abeoz9_rtc_get_time,
.set_time = abeoz9_rtc_set_time,
.read_alarm = abeoz9_rtc_read_alarm,
.set_alarm = abeoz9_rtc_set_alarm,
.alarm_irq_enable = abeoz9_rtc_alarm_irq_enable,
};
static const struct regmap_config abeoz9_rtc_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = 0x3f,
};
#if IS_REACHABLE(CONFIG_HWMON)
static int abeoz9z3_temp_read(struct device *dev,
enum hwmon_sensor_types type,
u32 attr, int channel, long *temp)
{
struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
int ret;
unsigned int val;
ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
if (ret < 0)
return ret;
switch (attr) {
case hwmon_temp_input:
ret = regmap_read(regmap, ABEOZ9_REG_REG_TEMP, &val);
if (ret < 0)
return ret;
*temp = 1000 * (val + ABEOZ953_TEMP_MIN);
return 0;
case hwmon_temp_max:
*temp = 1000 * ABEOZ953_TEMP_MAX;
return 0;
case hwmon_temp_min:
*temp = 1000 * ABEOZ953_TEMP_MIN;
return 0;
default:
return -EOPNOTSUPP;
}
}
static umode_t abeoz9_is_visible(const void *data,
enum hwmon_sensor_types type,
u32 attr, int channel)
{
switch (attr) {
case hwmon_temp_input:
case hwmon_temp_max:
case hwmon_temp_min:
return 0444;
default:
return 0;
}
}
static const u32 abeoz9_chip_config[] = {
HWMON_C_REGISTER_TZ,
0
};
static const struct hwmon_channel_info abeoz9_chip = {
.type = hwmon_chip,
.config = abeoz9_chip_config,
};
static const u32 abeoz9_temp_config[] = {
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN,
0
};
static const struct hwmon_channel_info abeoz9_temp = {
.type = hwmon_temp,
.config = abeoz9_temp_config,
};
static const struct hwmon_channel_info * const abeoz9_info[] = {
&abeoz9_chip,
&abeoz9_temp,
NULL
};
static const struct hwmon_ops abeoz9_hwmon_ops = {
.is_visible = abeoz9_is_visible,
.read = abeoz9z3_temp_read,
};
static const struct hwmon_chip_info abeoz9_chip_info = {
.ops = &abeoz9_hwmon_ops,
.info = abeoz9_info,
};
static void abeoz9_hwmon_register(struct device *dev,
struct abeoz9_rtc_data *data)
{
data->hwmon_dev =
devm_hwmon_device_register_with_info(dev,
"abeoz9",
data,
&abeoz9_chip_info,
NULL);
if (IS_ERR(data->hwmon_dev)) {
dev_warn(dev, "unable to register hwmon device %ld\n",
PTR_ERR(data->hwmon_dev));
}
}
#else
static void abeoz9_hwmon_register(struct device *dev,
struct abeoz9_rtc_data *data)
{
}
#endif
static int abeoz9_probe(struct i2c_client *client)
{
struct abeoz9_rtc_data *data = NULL;
struct device *dev = &client->dev;
struct regmap *regmap;
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_I2C_BLOCK))
return -ENODEV;
regmap = devm_regmap_init_i2c(client, &abeoz9_rtc_regmap_config);
if (IS_ERR(regmap)) {
ret = PTR_ERR(regmap);
dev_err(dev, "regmap allocation failed: %d\n", ret);
return ret;
}
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->regmap = regmap;
dev_set_drvdata(dev, data);
ret = abeoz9_rtc_setup(dev, client->dev.of_node);
if (ret)
return ret;
data->rtc = devm_rtc_allocate_device(dev);
ret = PTR_ERR_OR_ZERO(data->rtc);
if (ret)
return ret;
data->rtc->ops = &rtc_ops;
data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
data->rtc->range_max = RTC_TIMESTAMP_END_2099;
clear_bit(RTC_FEATURE_ALARM, data->rtc->features);
if (client->irq > 0) {
unsigned long irqflags = IRQF_TRIGGER_LOW;
if (dev_fwnode(&client->dev))
irqflags = 0;
ret = devm_request_threaded_irq(dev, client->irq, NULL,
abeoz9_rtc_irq,
irqflags | IRQF_ONESHOT,
dev_name(dev), dev);
if (ret) {
dev_err(dev, "failed to request alarm irq\n");
return ret;
}
} else {
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, data->rtc->features);
}
if (client->irq > 0 || device_property_read_bool(dev, "wakeup-source")) {
ret = device_init_wakeup(dev, true);
set_bit(RTC_FEATURE_ALARM, data->rtc->features);
}
ret = devm_rtc_register_device(data->rtc);
if (ret)
return ret;
abeoz9_hwmon_register(dev, data);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id abeoz9_dt_match[] = {
{ .compatible = "abracon,abeoz9" },
{ },
};
MODULE_DEVICE_TABLE(of, abeoz9_dt_match);
#endif
static const struct i2c_device_id abeoz9_id[] = {
{ "abeoz9" },
{ }
};
static struct i2c_driver abeoz9_driver = {
.driver = {
.name = "rtc-ab-eoz9",
.of_match_table = of_match_ptr(abeoz9_dt_match),
},
.probe = abeoz9_probe,
.id_table = abeoz9_id,
};
module_i2c_driver(abeoz9_driver);
MODULE_AUTHOR("Artem Panfilov <panfilov.artyom@gmail.com>");
MODULE_DESCRIPTION("Abracon AB-RTCMC-32.768kHz-EOZ9 RTC driver");
MODULE_LICENSE("GPL");
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