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linux/drivers/rtc/rtc-isl12057.c

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/*
* rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock
*
* Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org>
*
* This work is largely based on Intersil ISL1208 driver developed by
* Hebert Valerio Riedel <hvr@gnu.org>.
*
* Detailed datasheet on which this development is based is available here:
*
* http://natisbad.org/NAS2/refs/ISL12057.pdf
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rtc.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
#define DRV_NAME "rtc-isl12057"
/* RTC section */
#define ISL12057_REG_RTC_SC 0x00 /* Seconds */
#define ISL12057_REG_RTC_MN 0x01 /* Minutes */
#define ISL12057_REG_RTC_HR 0x02 /* Hours */
#define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */
#define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */
#define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */
#define ISL12057_REG_RTC_DT 0x04 /* Date */
#define ISL12057_REG_RTC_MO 0x05 /* Month */
#define ISL12057_REG_RTC_MO_CEN BIT(7) /* Century bit */
#define ISL12057_REG_RTC_YR 0x06 /* Year */
#define ISL12057_RTC_SEC_LEN 7
/* Alarm 1 section */
#define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */
#define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */
#define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */
#define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */
#define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */
#define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */
#define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */
#define ISL12057_A1_SEC_LEN 4
/* Alarm 2 section */
#define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */
#define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */
#define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */
#define ISL12057_A2_SEC_LEN 3
/* Control/Status registers */
#define ISL12057_REG_INT 0x0E
#define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */
#define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */
#define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */
#define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */
#define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */
#define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */
#define ISL12057_REG_SR 0x0F
#define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */
#define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */
#define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */
/* Register memory map length */
#define ISL12057_MEM_MAP_LEN 0x10
struct isl12057_rtc_data {
struct rtc_device *rtc;
struct regmap *regmap;
struct mutex lock;
int irq;
};
static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs)
{
tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]);
tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]);
if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */
tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x1f);
if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM)
tm->tm_hour += 12;
} else { /* 24 hour mode */
tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f);
}
tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]);
tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */
tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO] & 0x1f) - 1; /* ditto */
tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100;
/* Check if years register has overflown from 99 to 00 */
if (regs[ISL12057_REG_RTC_MO] & ISL12057_REG_RTC_MO_CEN)
tm->tm_year += 100;
}
static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm)
{
u8 century_bit;
/*
* The clock has an 8 bit wide bcd-coded register for the year.
* It also has a century bit encoded in MO flag which provides
* information about overflow of year register from 99 to 00.
* tm_year is an offset from 1900 and we are interested in the
* 2000-2199 range, so any value less than 100 or larger than
* 299 is invalid.
*/
if (tm->tm_year < 100 || tm->tm_year > 299)
return -EINVAL;
century_bit = (tm->tm_year > 199) ? ISL12057_REG_RTC_MO_CEN : 0;
regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec);
regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min);
regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */
regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday);
regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1) | century_bit;
regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year % 100);
regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1);
return 0;
}
/*
* Try and match register bits w/ fixed null values to see whether we
* are dealing with an ISL12057. Note: this function is called early
* during init and hence does need mutex protection.
*/
static int isl12057_i2c_validate_chip(struct regmap *regmap)
{
u8 regs[ISL12057_MEM_MAP_LEN];
static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8,
0xc0, 0x60, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x60, 0x7c };
int ret, i;
ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN);
if (ret)
return ret;
for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) {
if (regs[i] & mask[i]) /* check if bits are cleared */
return -ENODEV;
}
return 0;
}
static int _isl12057_rtc_clear_alarm(struct device *dev)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
int ret;
ret = regmap_update_bits(data->regmap, ISL12057_REG_SR,
ISL12057_REG_SR_A1F, 0);
if (ret)
dev_err(dev, "%s: clearing alarm failed (%d)\n", __func__, ret);
return ret;
}
static int _isl12057_rtc_update_alarm(struct device *dev, int enable)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
int ret;
ret = regmap_update_bits(data->regmap, ISL12057_REG_INT,
ISL12057_REG_INT_A1IE,
enable ? ISL12057_REG_INT_A1IE : 0);
if (ret)
dev_err(dev, "%s: changing alarm interrupt flag failed (%d)\n",
__func__, ret);
return ret;
}
/*
* Note: as we only read from device and do not perform any update, there is
* no need for an equivalent function which would try and get driver's main
* lock. Here, it is safe for everyone if we just use regmap internal lock
* on the device when reading.
*/
static int _isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
u8 regs[ISL12057_RTC_SEC_LEN];
unsigned int sr;
int ret;
ret = regmap_read(data->regmap, ISL12057_REG_SR, &sr);
if (ret) {
dev_err(dev, "%s: unable to read oscillator status flag (%d)\n",
__func__, ret);
goto out;
} else {
if (sr & ISL12057_REG_SR_OSF) {
ret = -ENODATA;
goto out;
}
}
ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs,
ISL12057_RTC_SEC_LEN);
if (ret)
dev_err(dev, "%s: unable to read RTC time section (%d)\n",
__func__, ret);
out:
if (ret)
return ret;
isl12057_rtc_regs_to_tm(tm, regs);
return rtc_valid_tm(tm);
}
static int isl12057_rtc_update_alarm(struct device *dev, int enable)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
int ret;
mutex_lock(&data->lock);
ret = _isl12057_rtc_update_alarm(dev, enable);
mutex_unlock(&data->lock);
return ret;
}
static int isl12057_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
struct rtc_time rtc_tm, *alarm_tm = &alarm->time;
unsigned long rtc_secs, alarm_secs;
u8 regs[ISL12057_A1_SEC_LEN];
unsigned int ir;
int ret;
mutex_lock(&data->lock);
ret = regmap_bulk_read(data->regmap, ISL12057_REG_A1_SC, regs,
ISL12057_A1_SEC_LEN);
if (ret) {
dev_err(dev, "%s: reading alarm section failed (%d)\n",
__func__, ret);
goto err_unlock;
}
alarm_tm->tm_sec = bcd2bin(regs[0] & 0x7f);
alarm_tm->tm_min = bcd2bin(regs[1] & 0x7f);
alarm_tm->tm_hour = bcd2bin(regs[2] & 0x3f);
alarm_tm->tm_mday = bcd2bin(regs[3] & 0x3f);
alarm_tm->tm_wday = -1;
/*
* The alarm section does not store year/month. We use the ones in rtc
* section as a basis and increment month and then year if needed to get
* alarm after current time.
*/
ret = _isl12057_rtc_read_time(dev, &rtc_tm);
if (ret)
goto err_unlock;
alarm_tm->tm_year = rtc_tm.tm_year;
alarm_tm->tm_mon = rtc_tm.tm_mon;
ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
if (ret)
goto err_unlock;
ret = rtc_tm_to_time(alarm_tm, &alarm_secs);
if (ret)
goto err_unlock;
if (alarm_secs < rtc_secs) {
if (alarm_tm->tm_mon == 11) {
alarm_tm->tm_mon = 0;
alarm_tm->tm_year += 1;
} else {
alarm_tm->tm_mon += 1;
}
}
ret = regmap_read(data->regmap, ISL12057_REG_INT, &ir);
if (ret) {
dev_err(dev, "%s: reading alarm interrupt flag failed (%d)\n",
__func__, ret);
goto err_unlock;
}
alarm->enabled = !!(ir & ISL12057_REG_INT_A1IE);
err_unlock:
mutex_unlock(&data->lock);
return ret;
}
static int isl12057_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
struct rtc_time *alarm_tm = &alarm->time;
unsigned long rtc_secs, alarm_secs;
u8 regs[ISL12057_A1_SEC_LEN];
struct rtc_time rtc_tm;
int ret, enable = 1;
mutex_lock(&data->lock);
ret = _isl12057_rtc_read_time(dev, &rtc_tm);
if (ret)
goto err_unlock;
ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
if (ret)
goto err_unlock;
ret = rtc_tm_to_time(alarm_tm, &alarm_secs);
if (ret)
goto err_unlock;
/* If alarm time is before current time, disable the alarm */
if (!alarm->enabled || alarm_secs <= rtc_secs) {
enable = 0;
} else {
/*
* Chip only support alarms up to one month in the future. Let's
* return an error if we get something after that limit.
* Comparison is done by incrementing rtc_tm month field by one
* and checking alarm value is still below.
*/
if (rtc_tm.tm_mon == 11) { /* handle year wrapping */
rtc_tm.tm_mon = 0;
rtc_tm.tm_year += 1;
} else {
rtc_tm.tm_mon += 1;
}
ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
if (ret)
goto err_unlock;
if (alarm_secs > rtc_secs) {
dev_err(dev, "%s: max for alarm is one month (%d)\n",
__func__, ret);
ret = -EINVAL;
goto err_unlock;
}
}
/* Disable the alarm before modifying it */
ret = _isl12057_rtc_update_alarm(dev, 0);
if (ret < 0) {
dev_err(dev, "%s: unable to disable the alarm (%d)\n",
__func__, ret);
goto err_unlock;
}
/* Program alarm registers */
regs[0] = bin2bcd(alarm_tm->tm_sec) & 0x7f;
regs[1] = bin2bcd(alarm_tm->tm_min) & 0x7f;
regs[2] = bin2bcd(alarm_tm->tm_hour) & 0x3f;
regs[3] = bin2bcd(alarm_tm->tm_mday) & 0x3f;
ret = regmap_bulk_write(data->regmap, ISL12057_REG_A1_SC, regs,
ISL12057_A1_SEC_LEN);
if (ret < 0) {
dev_err(dev, "%s: writing alarm section failed (%d)\n",
__func__, ret);
goto err_unlock;
}
/* Enable or disable alarm */
ret = _isl12057_rtc_update_alarm(dev, enable);
err_unlock:
mutex_unlock(&data->lock);
return ret;
}
static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
u8 regs[ISL12057_RTC_SEC_LEN];
int ret;
ret = isl12057_rtc_tm_to_regs(regs, tm);
if (ret)
return ret;
mutex_lock(&data->lock);
ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs,
ISL12057_RTC_SEC_LEN);
if (ret) {
dev_err(dev, "%s: unable to write RTC time section (%d)\n",
__func__, ret);
goto out;
}
/*
* Now that RTC time has been updated, let's clear oscillator
* failure flag, if needed.
*/
ret = regmap_update_bits(data->regmap, ISL12057_REG_SR,
ISL12057_REG_SR_OSF, 0);
if (ret < 0)
dev_err(dev, "%s: unable to clear osc. failure bit (%d)\n",
__func__, ret);
out:
mutex_unlock(&data->lock);
return ret;
}
/*
* Check current RTC status and enable/disable what needs to be. Return 0 if
* everything went ok and a negative value upon error. Note: this function
* is called early during init and hence does need mutex protection.
*/
static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap)
{
int ret;
/* Enable oscillator if not already running */
ret = regmap_update_bits(regmap, ISL12057_REG_INT,
ISL12057_REG_INT_EOSC, 0);
if (ret < 0) {
dev_err(dev, "%s: unable to enable oscillator (%d)\n",
__func__, ret);
return ret;
}
/* Clear alarm bit if needed */
ret = regmap_update_bits(regmap, ISL12057_REG_SR,
ISL12057_REG_SR_A1F, 0);
if (ret < 0) {
dev_err(dev, "%s: unable to clear alarm bit (%d)\n",
__func__, ret);
return ret;
}
return 0;
}
#ifdef CONFIG_OF
/*
* One would expect the device to be marked as a wakeup source only
* when an IRQ pin of the RTC is routed to an interrupt line of the
* CPU. In practice, such an IRQ pin can be connected to a PMIC and
* this allows the device to be powered up when RTC alarm rings. This
* is for instance the case on ReadyNAS 102, 104 and 2120. On those
* devices with no IRQ driectly connected to the SoC, the RTC chip
* can be forced as a wakeup source by stating that explicitly in
* the device's .dts file using the "wakeup-source" boolean property.
* This will guarantee 'wakealarm' sysfs entry is available on the device.
*
* The function below returns 1, i.e. the capability of the chip to
* wakeup the device, based on IRQ availability or if the boolean
* property has been set in the .dts file. Otherwise, it returns 0.
*/
static bool isl12057_can_wakeup_machine(struct device *dev)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
return data->irq || of_property_read_bool(dev->of_node, "wakeup-source")
|| of_property_read_bool(dev->of_node, /* legacy */
"isil,irq2-can-wakeup-machine");
}
#else
static bool isl12057_can_wakeup_machine(struct device *dev)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
return !!data->irq;
}
#endif
static int isl12057_rtc_alarm_irq_enable(struct device *dev,
unsigned int enable)
{
struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev);
int ret = -ENOTTY;
if (rtc_data->irq)
ret = isl12057_rtc_update_alarm(dev, enable);
return ret;
}
static irqreturn_t isl12057_rtc_interrupt(int irq, void *data)
{
struct i2c_client *client = data;
struct isl12057_rtc_data *rtc_data = dev_get_drvdata(&client->dev);
struct rtc_device *rtc = rtc_data->rtc;
int ret, handled = IRQ_NONE;
unsigned int sr;
ret = regmap_read(rtc_data->regmap, ISL12057_REG_SR, &sr);
if (!ret && (sr & ISL12057_REG_SR_A1F)) {
dev_dbg(&client->dev, "RTC alarm!\n");
rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
/* Acknowledge and disable the alarm */
_isl12057_rtc_clear_alarm(&client->dev);
_isl12057_rtc_update_alarm(&client->dev, 0);
handled = IRQ_HANDLED;
}
return handled;
}
static const struct rtc_class_ops rtc_ops = {
.read_time = _isl12057_rtc_read_time,
.set_time = isl12057_rtc_set_time,
.read_alarm = isl12057_rtc_read_alarm,
.set_alarm = isl12057_rtc_set_alarm,
.alarm_irq_enable = isl12057_rtc_alarm_irq_enable,
};
static const struct regmap_config isl12057_rtc_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
};
static int isl12057_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct isl12057_rtc_data *data;
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, &isl12057_rtc_regmap_config);
if (IS_ERR(regmap)) {
ret = PTR_ERR(regmap);
dev_err(dev, "%s: regmap allocation failed (%d)\n",
__func__, ret);
return ret;
}
ret = isl12057_i2c_validate_chip(regmap);
if (ret)
return ret;
ret = isl12057_check_rtc_status(dev, regmap);
if (ret)
return ret;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
mutex_init(&data->lock);
data->regmap = regmap;
dev_set_drvdata(dev, data);
if (client->irq > 0) {
ret = devm_request_threaded_irq(dev, client->irq, NULL,
isl12057_rtc_interrupt,
IRQF_SHARED|IRQF_ONESHOT,
DRV_NAME, client);
if (!ret)
data->irq = client->irq;
else
dev_err(dev, "%s: irq %d unavailable (%d)\n", __func__,
client->irq, ret);
}
if (isl12057_can_wakeup_machine(dev))
device_init_wakeup(dev, true);
data->rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops,
THIS_MODULE);
ret = PTR_ERR_OR_ZERO(data->rtc);
if (ret) {
dev_err(dev, "%s: unable to register RTC device (%d)\n",
__func__, ret);
goto err;
}
/* We cannot support UIE mode if we do not have an IRQ line */
if (!data->irq)
data->rtc->uie_unsupported = 1;
err:
return ret;
}
static int isl12057_remove(struct i2c_client *client)
{
if (isl12057_can_wakeup_machine(&client->dev))
device_init_wakeup(&client->dev, false);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int isl12057_rtc_suspend(struct device *dev)
{
struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev);
if (rtc_data->irq && device_may_wakeup(dev))
return enable_irq_wake(rtc_data->irq);
return 0;
}
static int isl12057_rtc_resume(struct device *dev)
{
struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev);
if (rtc_data->irq && device_may_wakeup(dev))
return disable_irq_wake(rtc_data->irq);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(isl12057_rtc_pm_ops, isl12057_rtc_suspend,
isl12057_rtc_resume);
#ifdef CONFIG_OF
static const struct of_device_id isl12057_dt_match[] = {
{ .compatible = "isl,isl12057" }, /* for backward compat., don't use */
{ .compatible = "isil,isl12057" },
{ },
};
MODULE_DEVICE_TABLE(of, isl12057_dt_match);
#endif
static const struct i2c_device_id isl12057_id[] = {
{ "isl12057", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, isl12057_id);
static struct i2c_driver isl12057_driver = {
.driver = {
.name = DRV_NAME,
.pm = &isl12057_rtc_pm_ops,
.of_match_table = of_match_ptr(isl12057_dt_match),
},
.probe = isl12057_probe,
.remove = isl12057_remove,
.id_table = isl12057_id,
};
module_i2c_driver(isl12057_driver);
MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>");
MODULE_DESCRIPTION("Intersil ISL12057 RTC driver");
MODULE_LICENSE("GPL");
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