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linux/drivers/rtc/rtc-max77802.c
Javier Martinez Canillas a4d4121ba7 rtc: add driver for Maxim 77802 PMIC Real-Time-Clock 
The MAX7802 PMIC has a Real-Time-Clock (RTC) with two alarms.  This
patch adds support for the RTC and is based on a driver added by Simon
Glass to the Chrome OS kernel 3.8 tree.

[akpm@linux-foundation.org: add comment clarifying ffs() use]
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Olof Johansson <olof@lixom.net>
Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:19 +02:00

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/*
* RTC driver for Maxim MAX77802
*
* Copyright (C) 2013 Google, Inc
*
* Copyright (C) 2012 Samsung Electronics Co.Ltd
*
* based on rtc-max8997.c
*
* 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.
*
*/
#include <linux/slab.h>
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mfd/max77686-private.h>
#include <linux/irqdomain.h>
#include <linux/regmap.h>
/* RTC Control Register */
#define BCD_EN_SHIFT 0
#define BCD_EN_MASK (1 << BCD_EN_SHIFT)
#define MODEL24_SHIFT 1
#define MODEL24_MASK (1 << MODEL24_SHIFT)
/* RTC Update Register1 */
#define RTC_UDR_SHIFT 0
#define RTC_UDR_MASK (1 << RTC_UDR_SHIFT)
#define RTC_RBUDR_SHIFT 4
#define RTC_RBUDR_MASK (1 << RTC_RBUDR_SHIFT)
/* RTC Hour register */
#define HOUR_PM_SHIFT 6
#define HOUR_PM_MASK (1 << HOUR_PM_SHIFT)
/* RTC Alarm Enable */
#define ALARM_ENABLE_SHIFT 7
#define ALARM_ENABLE_MASK (1 << ALARM_ENABLE_SHIFT)
/* For the RTCAE1 register, we write this value to enable the alarm */
#define ALARM_ENABLE_VALUE 0x77
#define MAX77802_RTC_UPDATE_DELAY_US 200
enum {
RTC_SEC = 0,
RTC_MIN,
RTC_HOUR,
RTC_WEEKDAY,
RTC_MONTH,
RTC_YEAR,
RTC_DATE,
RTC_NR_TIME
};
struct max77802_rtc_info {
struct device *dev;
struct max77686_dev *max77802;
struct i2c_client *rtc;
struct rtc_device *rtc_dev;
struct mutex lock;
struct regmap *regmap;
int virq;
int rtc_24hr_mode;
};
enum MAX77802_RTC_OP {
MAX77802_RTC_WRITE,
MAX77802_RTC_READ,
};
static void max77802_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
int rtc_24hr_mode)
{
tm->tm_sec = data[RTC_SEC] & 0xff;
tm->tm_min = data[RTC_MIN] & 0xff;
if (rtc_24hr_mode)
tm->tm_hour = data[RTC_HOUR] & 0x1f;
else {
tm->tm_hour = data[RTC_HOUR] & 0x0f;
if (data[RTC_HOUR] & HOUR_PM_MASK)
tm->tm_hour += 12;
}
/* Only a single bit is set in data[], so fls() would be equivalent */
tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0xff) - 1;
tm->tm_mday = data[RTC_DATE] & 0x1f;
tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
tm->tm_year = data[RTC_YEAR] & 0xff;
tm->tm_yday = 0;
tm->tm_isdst = 0;
}
static int max77802_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
{
data[RTC_SEC] = tm->tm_sec;
data[RTC_MIN] = tm->tm_min;
data[RTC_HOUR] = tm->tm_hour;
data[RTC_WEEKDAY] = 1 << tm->tm_wday;
data[RTC_DATE] = tm->tm_mday;
data[RTC_MONTH] = tm->tm_mon + 1;
data[RTC_YEAR] = tm->tm_year;
return 0;
}
static int max77802_rtc_update(struct max77802_rtc_info *info,
enum MAX77802_RTC_OP op)
{
int ret;
unsigned int data;
if (op == MAX77802_RTC_WRITE)
data = 1 << RTC_UDR_SHIFT;
else
data = 1 << RTC_RBUDR_SHIFT;
ret = regmap_update_bits(info->max77802->regmap,
MAX77802_RTC_UPDATE0, data, data);
if (ret < 0)
dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
__func__, ret, data);
else {
/* Minimum delay required before RTC update. */
usleep_range(MAX77802_RTC_UPDATE_DELAY_US,
MAX77802_RTC_UPDATE_DELAY_US * 2);
}
return ret;
}
static int max77802_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct max77802_rtc_info *info = dev_get_drvdata(dev);
u8 data[RTC_NR_TIME];
int ret;
mutex_lock(&info->lock);
ret = max77802_rtc_update(info, MAX77802_RTC_READ);
if (ret < 0)
goto out;
ret = regmap_bulk_read(info->max77802->regmap,
MAX77802_RTC_SEC, data, RTC_NR_TIME);
if (ret < 0) {
dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
ret);
goto out;
}
max77802_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
ret = rtc_valid_tm(tm);
out:
mutex_unlock(&info->lock);
return ret;
}
static int max77802_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct max77802_rtc_info *info = dev_get_drvdata(dev);
u8 data[RTC_NR_TIME];
int ret;
ret = max77802_rtc_tm_to_data(tm, data);
if (ret < 0)
return ret;
mutex_lock(&info->lock);
ret = regmap_bulk_write(info->max77802->regmap,
MAX77802_RTC_SEC, data, RTC_NR_TIME);
if (ret < 0) {
dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
ret);
goto out;
}
ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
out:
mutex_unlock(&info->lock);
return ret;
}
static int max77802_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct max77802_rtc_info *info = dev_get_drvdata(dev);
u8 data[RTC_NR_TIME];
unsigned int val;
int ret;
mutex_lock(&info->lock);
ret = max77802_rtc_update(info, MAX77802_RTC_READ);
if (ret < 0)
goto out;
ret = regmap_bulk_read(info->max77802->regmap,
MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
if (ret < 0) {
dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
__func__, __LINE__, ret);
goto out;
}
max77802_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
alrm->enabled = 0;
ret = regmap_read(info->max77802->regmap,
MAX77802_RTC_AE1, &val);
if (ret < 0) {
dev_err(info->dev, "%s:%d fail to read alarm enable(%d)\n",
__func__, __LINE__, ret);
goto out;
}
if (val)
alrm->enabled = 1;
alrm->pending = 0;
ret = regmap_read(info->max77802->regmap, MAX77802_REG_STATUS2, &val);
if (ret < 0) {
dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",
__func__, __LINE__, ret);
goto out;
}
if (val & (1 << 2)) /* RTCA1 */
alrm->pending = 1;
out:
mutex_unlock(&info->lock);
return 0;
}
static int max77802_rtc_stop_alarm(struct max77802_rtc_info *info)
{
int ret;
if (!mutex_is_locked(&info->lock))
dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
ret = max77802_rtc_update(info, MAX77802_RTC_READ);
if (ret < 0)
goto out;
ret = regmap_write(info->max77802->regmap,
MAX77802_RTC_AE1, 0);
if (ret < 0) {
dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
__func__, ret);
goto out;
}
ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
out:
return ret;
}
static int max77802_rtc_start_alarm(struct max77802_rtc_info *info)
{
int ret;
if (!mutex_is_locked(&info->lock))
dev_warn(info->dev, "%s: should have mutex locked\n",
__func__);
ret = max77802_rtc_update(info, MAX77802_RTC_READ);
if (ret < 0)
goto out;
ret = regmap_write(info->max77802->regmap,
MAX77802_RTC_AE1,
ALARM_ENABLE_VALUE);
if (ret < 0) {
dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
__func__, ret);
goto out;
}
ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
out:
return ret;
}
static int max77802_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct max77802_rtc_info *info = dev_get_drvdata(dev);
u8 data[RTC_NR_TIME];
int ret;
ret = max77802_rtc_tm_to_data(&alrm->time, data);
if (ret < 0)
return ret;
mutex_lock(&info->lock);
ret = max77802_rtc_stop_alarm(info);
if (ret < 0)
goto out;
ret = regmap_bulk_write(info->max77802->regmap,
MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
if (ret < 0) {
dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
__func__, ret);
goto out;
}
ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
if (ret < 0)
goto out;
if (alrm->enabled)
ret = max77802_rtc_start_alarm(info);
out:
mutex_unlock(&info->lock);
return ret;
}
static int max77802_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct max77802_rtc_info *info = dev_get_drvdata(dev);
int ret;
mutex_lock(&info->lock);
if (enabled)
ret = max77802_rtc_start_alarm(info);
else
ret = max77802_rtc_stop_alarm(info);
mutex_unlock(&info->lock);
return ret;
}
static irqreturn_t max77802_rtc_alarm_irq(int irq, void *data)
{
struct max77802_rtc_info *info = data;
dev_dbg(info->dev, "%s:irq(%d)\n", __func__, irq);
rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops max77802_rtc_ops = {
.read_time = max77802_rtc_read_time,
.set_time = max77802_rtc_set_time,
.read_alarm = max77802_rtc_read_alarm,
.set_alarm = max77802_rtc_set_alarm,
.alarm_irq_enable = max77802_rtc_alarm_irq_enable,
};
static int max77802_rtc_init_reg(struct max77802_rtc_info *info)
{
u8 data[2];
int ret;
max77802_rtc_update(info, MAX77802_RTC_READ);
/* Set RTC control register : Binary mode, 24hour mdoe */
data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
info->rtc_24hr_mode = 1;
ret = regmap_bulk_write(info->max77802->regmap,
MAX77802_RTC_CONTROLM, data, ARRAY_SIZE(data));
if (ret < 0) {
dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
__func__, ret);
return ret;
}
ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
return ret;
}
static int max77802_rtc_probe(struct platform_device *pdev)
{
struct max77686_dev *max77802 = dev_get_drvdata(pdev->dev.parent);
struct max77802_rtc_info *info;
int ret;
dev_dbg(&pdev->dev, "%s\n", __func__);
info = devm_kzalloc(&pdev->dev, sizeof(struct max77802_rtc_info),
GFP_KERNEL);
if (!info)
return -ENOMEM;
mutex_init(&info->lock);
info->dev = &pdev->dev;
info->max77802 = max77802;
info->rtc = max77802->i2c;
platform_set_drvdata(pdev, info);
ret = max77802_rtc_init_reg(info);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
return ret;
}
device_init_wakeup(&pdev->dev, 1);
info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77802-rtc",
&max77802_rtc_ops, THIS_MODULE);
if (IS_ERR(info->rtc_dev)) {
ret = PTR_ERR(info->rtc_dev);
dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
if (ret == 0)
ret = -EINVAL;
return ret;
}
if (!max77802->rtc_irq_data) {
dev_err(&pdev->dev, "No RTC regmap IRQ chip\n");
return -EINVAL;
}
info->virq = regmap_irq_get_virq(max77802->rtc_irq_data,
MAX77686_RTCIRQ_RTCA1);
if (info->virq <= 0) {
dev_err(&pdev->dev, "Failed to get virtual IRQ %d\n",
MAX77686_RTCIRQ_RTCA1);
return -EINVAL;
}
ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,
max77802_rtc_alarm_irq, 0, "rtc-alarm1",
info);
if (ret < 0)
dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
info->virq, ret);
return ret;
}
#ifdef CONFIG_PM_SLEEP
static int max77802_rtc_suspend(struct device *dev)
{
if (device_may_wakeup(dev)) {
struct max77802_rtc_info *info = dev_get_drvdata(dev);
return enable_irq_wake(info->virq);
}
return 0;
}
static int max77802_rtc_resume(struct device *dev)
{
if (device_may_wakeup(dev)) {
struct max77802_rtc_info *info = dev_get_drvdata(dev);
return disable_irq_wake(info->virq);
}
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(max77802_rtc_pm_ops,
max77802_rtc_suspend, max77802_rtc_resume);
static const struct platform_device_id rtc_id[] = {
{ "max77802-rtc", 0 },
{},
};
static struct platform_driver max77802_rtc_driver = {
.driver = {
.name = "max77802-rtc",
.owner = THIS_MODULE,
.pm = &max77802_rtc_pm_ops,
},
.probe = max77802_rtc_probe,
.id_table = rtc_id,
};
module_platform_driver(max77802_rtc_driver);
MODULE_DESCRIPTION("Maxim MAX77802 RTC driver");
MODULE_AUTHOR("Simon Glass <sjg@chromium.org>");
MODULE_LICENSE("GPL");
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