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linux/drivers/rtc/rtc-palmas.c
Laxman Dewangan 666a584d3a drivers/rtc/rtc-palmas.c: support for backup battery charging 
Palmas series device like TPS65913, TPS80036 supports the backup battery
for powering the RTC when no other energy source is available.

The backup battery is optional, connected to the VBACKUP pin, and can be
nonrechargeable or rechargeable.  The rechargeable battery can be charged
from the system supply using the backup battery charger.

Add support for enabling charging of this backup battery.  Also add the DT
binding document and the new properties to have this support.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Acked-by: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:58:55 -07:00

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/*
* rtc-palmas.c -- Palmas Real Time Clock driver.
* RTC driver for TI Palma series devices like TPS65913,
* TPS65914 power management IC.
*
* Copyright (c) 2012, NVIDIA Corporation.
*
* Author: Laxman Dewangan <ldewangan@nvidia.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 version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
* whether express or implied; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307, USA
*/
#include <linux/bcd.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mfd/palmas.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/rtc.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
struct palmas_rtc {
struct rtc_device *rtc;
struct device *dev;
unsigned int irq;
};
/* Total number of RTC registers needed to set time*/
#define PALMAS_NUM_TIME_REGS (PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
struct palmas *palmas = dev_get_drvdata(dev->parent);
int ret;
/* Copy RTC counting registers to static registers or latches */
ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME);
if (ret < 0) {
dev_err(dev, "RTC CTRL reg update failed, err: %d\n", ret);
return ret;
}
ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
rtc_data, PALMAS_NUM_TIME_REGS);
if (ret < 0) {
dev_err(dev, "RTC_SECONDS reg read failed, err = %d\n", ret);
return ret;
}
tm->tm_sec = bcd2bin(rtc_data[0]);
tm->tm_min = bcd2bin(rtc_data[1]);
tm->tm_hour = bcd2bin(rtc_data[2]);
tm->tm_mday = bcd2bin(rtc_data[3]);
tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
tm->tm_year = bcd2bin(rtc_data[5]) + 100;
return ret;
}
static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
struct palmas *palmas = dev_get_drvdata(dev->parent);
int ret;
rtc_data[0] = bin2bcd(tm->tm_sec);
rtc_data[1] = bin2bcd(tm->tm_min);
rtc_data[2] = bin2bcd(tm->tm_hour);
rtc_data[3] = bin2bcd(tm->tm_mday);
rtc_data[4] = bin2bcd(tm->tm_mon + 1);
rtc_data[5] = bin2bcd(tm->tm_year - 100);
/* Stop RTC while updating the RTC time registers */
ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
PALMAS_RTC_CTRL_REG_STOP_RTC, 0);
if (ret < 0) {
dev_err(dev, "RTC stop failed, err = %d\n", ret);
return ret;
}
ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
rtc_data, PALMAS_NUM_TIME_REGS);
if (ret < 0) {
dev_err(dev, "RTC_SECONDS reg write failed, err = %d\n", ret);
return ret;
}
/* Start back RTC */
ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
PALMAS_RTC_CTRL_REG_STOP_RTC, PALMAS_RTC_CTRL_REG_STOP_RTC);
if (ret < 0)
dev_err(dev, "RTC start failed, err = %d\n", ret);
return ret;
}
static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
{
struct palmas *palmas = dev_get_drvdata(dev->parent);
u8 val;
val = enabled ? PALMAS_RTC_INTERRUPTS_REG_IT_ALARM : 0;
return palmas_write(palmas, PALMAS_RTC_BASE,
PALMAS_RTC_INTERRUPTS_REG, val);
}
static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
u32 int_val;
struct palmas *palmas = dev_get_drvdata(dev->parent);
int ret;
ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE,
PALMAS_ALARM_SECONDS_REG,
alarm_data, PALMAS_NUM_TIME_REGS);
if (ret < 0) {
dev_err(dev, "RTC_ALARM_SECONDS read failed, err = %d\n", ret);
return ret;
}
alm->time.tm_sec = bcd2bin(alarm_data[0]);
alm->time.tm_min = bcd2bin(alarm_data[1]);
alm->time.tm_hour = bcd2bin(alarm_data[2]);
alm->time.tm_mday = bcd2bin(alarm_data[3]);
alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG,
&int_val);
if (ret < 0) {
dev_err(dev, "RTC_INTERRUPTS reg read failed, err = %d\n", ret);
return ret;
}
if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM)
alm->enabled = 1;
return ret;
}
static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
struct palmas *palmas = dev_get_drvdata(dev->parent);
int ret;
ret = palmas_rtc_alarm_irq_enable(dev, 0);
if (ret < 0) {
dev_err(dev, "Disable RTC alarm failed\n");
return ret;
}
alarm_data[0] = bin2bcd(alm->time.tm_sec);
alarm_data[1] = bin2bcd(alm->time.tm_min);
alarm_data[2] = bin2bcd(alm->time.tm_hour);
alarm_data[3] = bin2bcd(alm->time.tm_mday);
alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE,
PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS);
if (ret < 0) {
dev_err(dev, "ALARM_SECONDS_REG write failed, err = %d\n", ret);
return ret;
}
if (alm->enabled)
ret = palmas_rtc_alarm_irq_enable(dev, 1);
return ret;
}
static int palmas_clear_interrupts(struct device *dev)
{
struct palmas *palmas = dev_get_drvdata(dev->parent);
unsigned int rtc_reg;
int ret;
ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
&rtc_reg);
if (ret < 0) {
dev_err(dev, "RTC_STATUS read failed, err = %d\n", ret);
return ret;
}
ret = palmas_write(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
rtc_reg);
if (ret < 0) {
dev_err(dev, "RTC_STATUS write failed, err = %d\n", ret);
return ret;
}
return 0;
}
static irqreturn_t palmas_rtc_interrupt(int irq, void *context)
{
struct palmas_rtc *palmas_rtc = context;
struct device *dev = palmas_rtc->dev;
int ret;
ret = palmas_clear_interrupts(dev);
if (ret < 0) {
dev_err(dev, "RTC interrupt clear failed, err = %d\n", ret);
return IRQ_NONE;
}
rtc_update_irq(palmas_rtc->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static struct rtc_class_ops palmas_rtc_ops = {
.read_time = palmas_rtc_read_time,
.set_time = palmas_rtc_set_time,
.read_alarm = palmas_rtc_read_alarm,
.set_alarm = palmas_rtc_set_alarm,
.alarm_irq_enable = palmas_rtc_alarm_irq_enable,
};
static int palmas_rtc_probe(struct platform_device *pdev)
{
struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
struct palmas_rtc *palmas_rtc = NULL;
int ret;
bool enable_bb_charging = false;
bool high_bb_charging;
if (pdev->dev.of_node) {
enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
"ti,backup-battery-chargeable");
high_bb_charging = of_property_read_bool(pdev->dev.of_node,
"ti,backup-battery-charge-high-current");
}
palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
GFP_KERNEL);
if (!palmas_rtc)
return -ENOMEM;
/* Clear pending interrupts */
ret = palmas_clear_interrupts(&pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "clear RTC int failed, err = %d\n", ret);
return ret;
}
palmas_rtc->dev = &pdev->dev;
platform_set_drvdata(pdev, palmas_rtc);
if (enable_bb_charging) {
unsigned reg = PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
if (high_bb_charging)
reg = 0;
ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
PALMAS_BACKUP_BATTERY_CTRL,
PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg);
if (ret < 0) {
dev_err(&pdev->dev,
"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
return ret;
}
ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
PALMAS_BACKUP_BATTERY_CTRL,
PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN,
PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN);
if (ret < 0) {
dev_err(&pdev->dev,
"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
return ret;
}
}
/* Start RTC */
ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
PALMAS_RTC_CTRL_REG_STOP_RTC,
PALMAS_RTC_CTRL_REG_STOP_RTC);
if (ret < 0) {
dev_err(&pdev->dev, "RTC_CTRL write failed, err = %d\n", ret);
return ret;
}
palmas_rtc->irq = platform_get_irq(pdev, 0);
device_init_wakeup(&pdev->dev, 1);
palmas_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&palmas_rtc_ops, THIS_MODULE);
if (IS_ERR(palmas_rtc->rtc)) {
ret = PTR_ERR(palmas_rtc->rtc);
dev_err(&pdev->dev, "RTC register failed, err = %d\n", ret);
return ret;
}
ret = devm_request_threaded_irq(&pdev->dev, palmas_rtc->irq, NULL,
palmas_rtc_interrupt,
IRQF_TRIGGER_LOW | IRQF_ONESHOT |
IRQF_EARLY_RESUME,
dev_name(&pdev->dev), palmas_rtc);
if (ret < 0) {
dev_err(&pdev->dev, "IRQ request failed, err = %d\n", ret);
return ret;
}
return 0;
}
static int palmas_rtc_remove(struct platform_device *pdev)
{
palmas_rtc_alarm_irq_enable(&pdev->dev, 0);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int palmas_rtc_suspend(struct device *dev)
{
struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(palmas_rtc->irq);
return 0;
}
static int palmas_rtc_resume(struct device *dev)
{
struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(palmas_rtc->irq);
return 0;
}
#endif
static const struct dev_pm_ops palmas_rtc_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(palmas_rtc_suspend, palmas_rtc_resume)
};
#ifdef CONFIG_OF
static struct of_device_id of_palmas_rtc_match[] = {
{ .compatible = "ti,palmas-rtc"},
{ },
};
MODULE_DEVICE_TABLE(of, of_palmas_rtc_match);
#endif
static struct platform_driver palmas_rtc_driver = {
.probe = palmas_rtc_probe,
.remove = palmas_rtc_remove,
.driver = {
.owner = THIS_MODULE,
.name = "palmas-rtc",
.pm = &palmas_rtc_pm_ops,
.of_match_table = of_match_ptr(of_palmas_rtc_match),
},
};
module_platform_driver(palmas_rtc_driver);
MODULE_ALIAS("platform:palmas_rtc");
MODULE_DESCRIPTION("TI PALMAS series RTC driver");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL v2");
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