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linux/drivers/rtc/rtc-max8998.c
MyungJoo Ham 337ce5d1c5 mfd: Support LP3974 RTC 
The first releases of LP3974 have a large delay in RTC registers,
which requires 2 seconds of delay after writing to a rtc register
(recommended by National Semiconductor's engineers)
before reading it.

If "rtc_delay" field of the platform data is true, the rtc driver
assumes that such delays are required. Although we have not seen
LP3974s without requiring such delays, we assume that such LP3974s
will be released soon (or they have done so already) and they are
supported by "lp3974" without setting "rtc_delay" at the platform
data.

This patch adds delays with msleep when writing values to RTC registers
if the platform data has rtc_delay set.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2011-01-14 12:38:16 +01:00

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/*
* RTC driver for Maxim MAX8998
*
* Copyright (C) 2010 Samsung Electronics Co.Ltd
* Author: Minkyu Kang <mk7.kang@samsung.com>
* Author: Joonyoung Shim <jy0922.shim@samsung.com>
*
* 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/module.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/mfd/max8998.h>
#include <linux/mfd/max8998-private.h>
#include <linux/delay.h>
#define MAX8998_RTC_SEC 0x00
#define MAX8998_RTC_MIN 0x01
#define MAX8998_RTC_HOUR 0x02
#define MAX8998_RTC_WEEKDAY 0x03
#define MAX8998_RTC_DATE 0x04
#define MAX8998_RTC_MONTH 0x05
#define MAX8998_RTC_YEAR1 0x06
#define MAX8998_RTC_YEAR2 0x07
#define MAX8998_ALARM0_SEC 0x08
#define MAX8998_ALARM0_MIN 0x09
#define MAX8998_ALARM0_HOUR 0x0a
#define MAX8998_ALARM0_WEEKDAY 0x0b
#define MAX8998_ALARM0_DATE 0x0c
#define MAX8998_ALARM0_MONTH 0x0d
#define MAX8998_ALARM0_YEAR1 0x0e
#define MAX8998_ALARM0_YEAR2 0x0f
#define MAX8998_ALARM1_SEC 0x10
#define MAX8998_ALARM1_MIN 0x11
#define MAX8998_ALARM1_HOUR 0x12
#define MAX8998_ALARM1_WEEKDAY 0x13
#define MAX8998_ALARM1_DATE 0x14
#define MAX8998_ALARM1_MONTH 0x15
#define MAX8998_ALARM1_YEAR1 0x16
#define MAX8998_ALARM1_YEAR2 0x17
#define MAX8998_ALARM0_CONF 0x18
#define MAX8998_ALARM1_CONF 0x19
#define MAX8998_RTC_STATUS 0x1a
#define MAX8998_WTSR_SMPL_CNTL 0x1b
#define MAX8998_TEST 0x1f
#define HOUR_12 (1 << 7)
#define HOUR_PM (1 << 5)
#define ALARM0_STATUS (1 << 1)
#define ALARM1_STATUS (1 << 2)
enum {
RTC_SEC = 0,
RTC_MIN,
RTC_HOUR,
RTC_WEEKDAY,
RTC_DATE,
RTC_MONTH,
RTC_YEAR1,
RTC_YEAR2,
};
struct max8998_rtc_info {
struct device *dev;
struct max8998_dev *max8998;
struct i2c_client *rtc;
struct rtc_device *rtc_dev;
int irq;
bool lp3974_bug_workaround;
};
static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
{
tm->tm_sec = bcd2bin(data[RTC_SEC]);
tm->tm_min = bcd2bin(data[RTC_MIN]);
if (data[RTC_HOUR] & HOUR_12) {
tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);
if (data[RTC_HOUR] & HOUR_PM)
tm->tm_hour += 12;
} else
tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
tm->tm_wday = data[RTC_WEEKDAY] & 0x07;
tm->tm_mday = bcd2bin(data[RTC_DATE]);
tm->tm_mon = bcd2bin(data[RTC_MONTH]);
tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;
tm->tm_year -= 1900;
}
static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)
{
data[RTC_SEC] = bin2bcd(tm->tm_sec);
data[RTC_MIN] = bin2bcd(tm->tm_min);
data[RTC_HOUR] = bin2bcd(tm->tm_hour);
data[RTC_WEEKDAY] = tm->tm_wday;
data[RTC_DATE] = bin2bcd(tm->tm_mday);
data[RTC_MONTH] = bin2bcd(tm->tm_mon);
data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);
data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
}
static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct max8998_rtc_info *info = dev_get_drvdata(dev);
u8 data[8];
int ret;
ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);
if (ret < 0)
return ret;
max8998_data_to_tm(data, tm);
return rtc_valid_tm(tm);
}
static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct max8998_rtc_info *info = dev_get_drvdata(dev);
u8 data[8];
int ret;
max8998_tm_to_data(tm, data);
ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
if (info->lp3974_bug_workaround)
msleep(2000);
return ret;
}
static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct max8998_rtc_info *info = dev_get_drvdata(dev);
u8 data[8];
u8 val;
int ret;
ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);
if (ret < 0)
return ret;
max8998_data_to_tm(data, &alrm->time);
ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);
if (ret < 0)
return ret;
alrm->enabled = !!val;
ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);
if (ret < 0)
return ret;
if (val & ALARM0_STATUS)
alrm->pending = 1;
else
alrm->pending = 0;
return 0;
}
static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
{
int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
if (info->lp3974_bug_workaround)
msleep(2000);
return ret;
}
static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
{
int ret;
u8 alarm0_conf = 0x77;
/* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */
if (info->lp3974_bug_workaround)
alarm0_conf = 0x57;
ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);
if (info->lp3974_bug_workaround)
msleep(2000);
return ret;
}
static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct max8998_rtc_info *info = dev_get_drvdata(dev);
u8 data[8];
int ret;
max8998_tm_to_data(&alrm->time, data);
ret = max8998_rtc_stop_alarm(info);
if (ret < 0)
return ret;
ret = max8998_bulk_write(info->rtc, MAX8998_ALARM0_SEC, 8, data);
if (ret < 0)
return ret;
if (info->lp3974_bug_workaround)
msleep(2000);
if (alrm->enabled)
ret = max8998_rtc_start_alarm(info);
return ret;
}
static int max8998_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct max8998_rtc_info *info = dev_get_drvdata(dev);
if (enabled)
return max8998_rtc_start_alarm(info);
else
return max8998_rtc_stop_alarm(info);
}
static irqreturn_t max8998_rtc_alarm_irq(int irq, void *data)
{
struct max8998_rtc_info *info = data;
rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops max8998_rtc_ops = {
.read_time = max8998_rtc_read_time,
.set_time = max8998_rtc_set_time,
.read_alarm = max8998_rtc_read_alarm,
.set_alarm = max8998_rtc_set_alarm,
.alarm_irq_enable = max8998_rtc_alarm_irq_enable,
};
static int __devinit max8998_rtc_probe(struct platform_device *pdev)
{
struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
struct max8998_platform_data *pdata = dev_get_platdata(max8998->dev);
struct max8998_rtc_info *info;
int ret;
info = kzalloc(sizeof(struct max8998_rtc_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
info->dev = &pdev->dev;
info->max8998 = max8998;
info->rtc = max8998->rtc;
info->irq = max8998->irq_base + MAX8998_IRQ_ALARM0;
info->rtc_dev = rtc_device_register("max8998-rtc", &pdev->dev,
&max8998_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);
goto out_rtc;
}
platform_set_drvdata(pdev, info);
ret = request_threaded_irq(info->irq, NULL, max8998_rtc_alarm_irq, 0,
"rtc-alarm0", info);
if (ret < 0)
dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
info->irq, ret);
dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);
if (pdata->rtc_delay) {
info->lp3974_bug_workaround = true;
dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
" RTC updates will be extremely slow.\n");
}
return 0;
out_rtc:
kfree(info);
return ret;
}
static int __devexit max8998_rtc_remove(struct platform_device *pdev)
{
struct max8998_rtc_info *info = platform_get_drvdata(pdev);
if (info) {
free_irq(info->irq, info);
rtc_device_unregister(info->rtc_dev);
kfree(info);
}
return 0;
}
static const struct platform_device_id max8998_rtc_id[] = {
{ "max8998-rtc", TYPE_MAX8998 },
{ "lp3974-rtc", TYPE_LP3974 },
{ }
};
static struct platform_driver max8998_rtc_driver = {
.driver = {
.name = "max8998-rtc",
.owner = THIS_MODULE,
},
.probe = max8998_rtc_probe,
.remove = __devexit_p(max8998_rtc_remove),
.id_table = max8998_rtc_id,
};
static int __init max8998_rtc_init(void)
{
return platform_driver_register(&max8998_rtc_driver);
}
module_init(max8998_rtc_init);
static void __exit max8998_rtc_exit(void)
{
platform_driver_unregister(&max8998_rtc_driver);
}
module_exit(max8998_rtc_exit);
MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
MODULE_LICENSE("GPL");
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