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linux/drivers/rtc/rtc-twl.c

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/*
* rtc-twl.c -- TWL Real Time Clock interface
*
* Copyright (C) 2007 MontaVista Software, Inc
* Author: Alexandre Rusev <source@mvista.com>
*
* Based on original TI driver twl4030-rtc.c
* Copyright (C) 2006 Texas Instruments, Inc.
*
* Based on rtc-omap.c
* Copyright (C) 2003 MontaVista Software, Inc.
* Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
* Copyright (C) 2006 David Brownell
*
* 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/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/i2c/twl.h>
/*
* RTC block register offsets (use TWL_MODULE_RTC)
*/
enum {
REG_SECONDS_REG = 0,
REG_MINUTES_REG,
REG_HOURS_REG,
REG_DAYS_REG,
REG_MONTHS_REG,
REG_YEARS_REG,
REG_WEEKS_REG,
REG_ALARM_SECONDS_REG,
REG_ALARM_MINUTES_REG,
REG_ALARM_HOURS_REG,
REG_ALARM_DAYS_REG,
REG_ALARM_MONTHS_REG,
REG_ALARM_YEARS_REG,
REG_RTC_CTRL_REG,
REG_RTC_STATUS_REG,
REG_RTC_INTERRUPTS_REG,
REG_RTC_COMP_LSB_REG,
REG_RTC_COMP_MSB_REG,
};
static const u8 twl4030_rtc_reg_map[] = {
[REG_SECONDS_REG] = 0x00,
[REG_MINUTES_REG] = 0x01,
[REG_HOURS_REG] = 0x02,
[REG_DAYS_REG] = 0x03,
[REG_MONTHS_REG] = 0x04,
[REG_YEARS_REG] = 0x05,
[REG_WEEKS_REG] = 0x06,
[REG_ALARM_SECONDS_REG] = 0x07,
[REG_ALARM_MINUTES_REG] = 0x08,
[REG_ALARM_HOURS_REG] = 0x09,
[REG_ALARM_DAYS_REG] = 0x0A,
[REG_ALARM_MONTHS_REG] = 0x0B,
[REG_ALARM_YEARS_REG] = 0x0C,
[REG_RTC_CTRL_REG] = 0x0D,
[REG_RTC_STATUS_REG] = 0x0E,
[REG_RTC_INTERRUPTS_REG] = 0x0F,
[REG_RTC_COMP_LSB_REG] = 0x10,
[REG_RTC_COMP_MSB_REG] = 0x11,
};
static const u8 twl6030_rtc_reg_map[] = {
[REG_SECONDS_REG] = 0x00,
[REG_MINUTES_REG] = 0x01,
[REG_HOURS_REG] = 0x02,
[REG_DAYS_REG] = 0x03,
[REG_MONTHS_REG] = 0x04,
[REG_YEARS_REG] = 0x05,
[REG_WEEKS_REG] = 0x06,
[REG_ALARM_SECONDS_REG] = 0x08,
[REG_ALARM_MINUTES_REG] = 0x09,
[REG_ALARM_HOURS_REG] = 0x0A,
[REG_ALARM_DAYS_REG] = 0x0B,
[REG_ALARM_MONTHS_REG] = 0x0C,
[REG_ALARM_YEARS_REG] = 0x0D,
[REG_RTC_CTRL_REG] = 0x10,
[REG_RTC_STATUS_REG] = 0x11,
[REG_RTC_INTERRUPTS_REG] = 0x12,
[REG_RTC_COMP_LSB_REG] = 0x13,
[REG_RTC_COMP_MSB_REG] = 0x14,
};
/* RTC_CTRL_REG bitfields */
#define BIT_RTC_CTRL_REG_STOP_RTC_M 0x01
#define BIT_RTC_CTRL_REG_ROUND_30S_M 0x02
#define BIT_RTC_CTRL_REG_AUTO_COMP_M 0x04
#define BIT_RTC_CTRL_REG_MODE_12_24_M 0x08
#define BIT_RTC_CTRL_REG_TEST_MODE_M 0x10
#define BIT_RTC_CTRL_REG_SET_32_COUNTER_M 0x20
#define BIT_RTC_CTRL_REG_GET_TIME_M 0x40
#define BIT_RTC_CTRL_REG_RTC_V_OPT 0x80
/* RTC_STATUS_REG bitfields */
#define BIT_RTC_STATUS_REG_RUN_M 0x02
#define BIT_RTC_STATUS_REG_1S_EVENT_M 0x04
#define BIT_RTC_STATUS_REG_1M_EVENT_M 0x08
#define BIT_RTC_STATUS_REG_1H_EVENT_M 0x10
#define BIT_RTC_STATUS_REG_1D_EVENT_M 0x20
#define BIT_RTC_STATUS_REG_ALARM_M 0x40
#define BIT_RTC_STATUS_REG_POWER_UP_M 0x80
/* RTC_INTERRUPTS_REG bitfields */
#define BIT_RTC_INTERRUPTS_REG_EVERY_M 0x03
#define BIT_RTC_INTERRUPTS_REG_IT_TIMER_M 0x04
#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M 0x08
/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
#define ALL_TIME_REGS 6
/*----------------------------------------------------------------------*/
static u8 *rtc_reg_map;
/*
* Supports 1 byte read from TWL RTC register.
*/
static int twl_rtc_read_u8(u8 *data, u8 reg)
{
int ret;
ret = twl_i2c_read_u8(TWL_MODULE_RTC, data, (rtc_reg_map[reg]));
if (ret < 0)
pr_err("twl_rtc: Could not read TWL"
"register %X - error %d\n", reg, ret);
return ret;
}
/*
* Supports 1 byte write to TWL RTC registers.
*/
static int twl_rtc_write_u8(u8 data, u8 reg)
{
int ret;
ret = twl_i2c_write_u8(TWL_MODULE_RTC, data, (rtc_reg_map[reg]));
if (ret < 0)
pr_err("twl_rtc: Could not write TWL"
"register %X - error %d\n", reg, ret);
return ret;
}
/*
* Cache the value for timer/alarm interrupts register; this is
* only changed by callers holding rtc ops lock (or resume).
*/
static unsigned char rtc_irq_bits;
/*
* Enable 1/second update and/or alarm interrupts.
*/
static int set_rtc_irq_bit(unsigned char bit)
{
unsigned char val;
int ret;
/* if the bit is set, return from here */
if (rtc_irq_bits & bit)
return 0;
val = rtc_irq_bits | bit;
val &= ~BIT_RTC_INTERRUPTS_REG_EVERY_M;
ret = twl_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG);
if (ret == 0)
rtc_irq_bits = val;
return ret;
}
/*
* Disable update and/or alarm interrupts.
*/
static int mask_rtc_irq_bit(unsigned char bit)
{
unsigned char val;
int ret;
/* if the bit is clear, return from here */
if (!(rtc_irq_bits & bit))
return 0;
val = rtc_irq_bits & ~bit;
ret = twl_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG);
if (ret == 0)
rtc_irq_bits = val;
return ret;
}
static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
{
struct platform_device *pdev = to_platform_device(dev);
int irq = platform_get_irq(pdev, 0);
static bool twl_rtc_wake_enabled;
int ret;
if (enabled) {
ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
enable_irq_wake(irq);
twl_rtc_wake_enabled = true;
}
} else {
ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
if (twl_rtc_wake_enabled) {
disable_irq_wake(irq);
twl_rtc_wake_enabled = false;
}
}
return ret;
}
/*
* Gets current TWL RTC time and date parameters.
*
* The RTC's time/alarm representation is not what gmtime(3) requires
* Linux to use:
*
* - Months are 1..12 vs Linux 0-11
* - Years are 0..99 vs Linux 1900..N (we assume 21st century)
*/
static int twl_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
unsigned char rtc_data[ALL_TIME_REGS];
int ret;
u8 save_control;
u8 rtc_control;
ret = twl_rtc_read_u8(&save_control, REG_RTC_CTRL_REG);
if (ret < 0) {
dev_err(dev, "%s: reading CTRL_REG, error %d\n", __func__, ret);
return ret;
}
/* for twl6030/32 make sure BIT_RTC_CTRL_REG_GET_TIME_M is clear */
if (twl_class_is_6030()) {
if (save_control & BIT_RTC_CTRL_REG_GET_TIME_M) {
save_control &= ~BIT_RTC_CTRL_REG_GET_TIME_M;
ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
if (ret < 0) {
dev_err(dev, "%s clr GET_TIME, error %d\n",
__func__, ret);
return ret;
}
}
}
/* Copy RTC counting registers to static registers or latches */
rtc_control = save_control | BIT_RTC_CTRL_REG_GET_TIME_M;
/* for twl6030/32 enable read access to static shadowed registers */
if (twl_class_is_6030())
rtc_control |= BIT_RTC_CTRL_REG_RTC_V_OPT;
ret = twl_rtc_write_u8(rtc_control, REG_RTC_CTRL_REG);
if (ret < 0) {
dev_err(dev, "%s: writing CTRL_REG, error %d\n", __func__, ret);
return ret;
}
ret = twl_i2c_read(TWL_MODULE_RTC, rtc_data,
(rtc_reg_map[REG_SECONDS_REG]), ALL_TIME_REGS);
if (ret < 0) {
dev_err(dev, "%s: reading data, error %d\n", __func__, ret);
return ret;
}
/* for twl6030 restore original state of rtc control register */
if (twl_class_is_6030()) {
ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
if (ret < 0) {
dev_err(dev, "%s: restore CTRL_REG, error %d\n",
__func__, 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 twl_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
unsigned char save_control;
unsigned char rtc_data[ALL_TIME_REGS];
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 TC registers */
ret = twl_rtc_read_u8(&save_control, REG_RTC_CTRL_REG);
if (ret < 0)
goto out;
save_control &= ~BIT_RTC_CTRL_REG_STOP_RTC_M;
ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
if (ret < 0)
goto out;
/* update all the time registers in one shot */
ret = twl_i2c_write(TWL_MODULE_RTC, rtc_data,
(rtc_reg_map[REG_SECONDS_REG]), ALL_TIME_REGS);
if (ret < 0) {
dev_err(dev, "rtc_set_time error %d\n", ret);
goto out;
}
/* Start back RTC */
save_control |= BIT_RTC_CTRL_REG_STOP_RTC_M;
ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG);
out:
return ret;
}
/*
* Gets current TWL RTC alarm time.
*/
static int twl_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
unsigned char rtc_data[ALL_TIME_REGS];
int ret;
ret = twl_i2c_read(TWL_MODULE_RTC, rtc_data,
(rtc_reg_map[REG_ALARM_SECONDS_REG]), ALL_TIME_REGS);
if (ret < 0) {
dev_err(dev, "rtc_read_alarm error %d\n", ret);
return ret;
}
/* some of these fields may be wildcard/"match all" */
alm->time.tm_sec = bcd2bin(rtc_data[0]);
alm->time.tm_min = bcd2bin(rtc_data[1]);
alm->time.tm_hour = bcd2bin(rtc_data[2]);
alm->time.tm_mday = bcd2bin(rtc_data[3]);
alm->time.tm_mon = bcd2bin(rtc_data[4]) - 1;
alm->time.tm_year = bcd2bin(rtc_data[5]) + 100;
/* report cached alarm enable state */
if (rtc_irq_bits & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M)
alm->enabled = 1;
return ret;
}
static int twl_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
unsigned char alarm_data[ALL_TIME_REGS];
int ret;
ret = twl_rtc_alarm_irq_enable(dev, 0);
if (ret)
goto out;
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);
/* update all the alarm registers in one shot */
ret = twl_i2c_write(TWL_MODULE_RTC, alarm_data,
(rtc_reg_map[REG_ALARM_SECONDS_REG]), ALL_TIME_REGS);
if (ret) {
dev_err(dev, "rtc_set_alarm error %d\n", ret);
goto out;
}
if (alm->enabled)
ret = twl_rtc_alarm_irq_enable(dev, 1);
out:
return ret;
}
static irqreturn_t twl_rtc_interrupt(int irq, void *rtc)
{
unsigned long events;
int ret = IRQ_NONE;
int res;
u8 rd_reg;
res = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG);
if (res)
goto out;
/*
* Figure out source of interrupt: ALARM or TIMER in RTC_STATUS_REG.
* only one (ALARM or RTC) interrupt source may be enabled
* at time, we also could check our results
* by reading RTS_INTERRUPTS_REGISTER[IT_TIMER,IT_ALARM]
*/
if (rd_reg & BIT_RTC_STATUS_REG_ALARM_M)
events = RTC_IRQF | RTC_AF;
else
events = RTC_IRQF | RTC_PF;
res = twl_rtc_write_u8(BIT_RTC_STATUS_REG_ALARM_M,
REG_RTC_STATUS_REG);
if (res)
goto out;
if (twl_class_is_4030()) {
/* Clear on Read enabled. RTC_IT bit of TWL4030_INT_PWR_ISR1
* needs 2 reads to clear the interrupt. One read is done in
* do_twl_pwrirq(). Doing the second read, to clear
* the bit.
*
* FIXME the reason PWR_ISR1 needs an extra read is that
* RTC_IF retriggered until we cleared REG_ALARM_M above.
* But re-reading like this is a bad hack; by doing so we
* risk wrongly clearing status for some other IRQ (losing
* the interrupt). Be smarter about handling RTC_UF ...
*/
res = twl_i2c_read_u8(TWL4030_MODULE_INT,
&rd_reg, TWL4030_INT_PWR_ISR1);
if (res)
goto out;
}
/* Notify RTC core on event */
rtc_update_irq(rtc, 1, events);
ret = IRQ_HANDLED;
out:
return ret;
}
static struct rtc_class_ops twl_rtc_ops = {
.read_time = twl_rtc_read_time,
.set_time = twl_rtc_set_time,
.read_alarm = twl_rtc_read_alarm,
.set_alarm = twl_rtc_set_alarm,
.alarm_irq_enable = twl_rtc_alarm_irq_enable,
};
/*----------------------------------------------------------------------*/
static int twl_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
int ret = -EINVAL;
int irq = platform_get_irq(pdev, 0);
u8 rd_reg;
if (irq <= 0)
return ret;
/* Initialize the register map */
if (twl_class_is_4030())
rtc_reg_map = (u8 *)twl4030_rtc_reg_map;
else
rtc_reg_map = (u8 *)twl6030_rtc_reg_map;
ret = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG);
if (ret < 0)
return ret;
if (rd_reg & BIT_RTC_STATUS_REG_POWER_UP_M)
dev_warn(&pdev->dev, "Power up reset detected.\n");
if (rd_reg & BIT_RTC_STATUS_REG_ALARM_M)
dev_warn(&pdev->dev, "Pending Alarm interrupt detected.\n");
/* Clear RTC Power up reset and pending alarm interrupts */
ret = twl_rtc_write_u8(rd_reg, REG_RTC_STATUS_REG);
if (ret < 0)
return ret;
if (twl_class_is_6030()) {
twl6030_interrupt_unmask(TWL6030_RTC_INT_MASK,
REG_INT_MSK_LINE_A);
twl6030_interrupt_unmask(TWL6030_RTC_INT_MASK,
REG_INT_MSK_STS_A);
}
dev_info(&pdev->dev, "Enabling TWL-RTC\n");
ret = twl_rtc_write_u8(BIT_RTC_CTRL_REG_STOP_RTC_M, REG_RTC_CTRL_REG);
if (ret < 0)
return ret;
/* ensure interrupts are disabled, bootloaders can be strange */
ret = twl_rtc_write_u8(0, REG_RTC_INTERRUPTS_REG);
if (ret < 0)
dev_warn(&pdev->dev, "unable to disable interrupt\n");
/* init cached IRQ enable bits */
ret = twl_rtc_read_u8(&rtc_irq_bits, REG_RTC_INTERRUPTS_REG);
if (ret < 0)
return ret;
device_init_wakeup(&pdev->dev, 1);
rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&twl_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
PTR_ERR(rtc));
return PTR_ERR(rtc);
}
ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
twl_rtc_interrupt,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
dev_name(&rtc->dev), rtc);
if (ret < 0) {
dev_err(&pdev->dev, "IRQ is not free.\n");
return ret;
}
platform_set_drvdata(pdev, rtc);
return 0;
}
/*
* Disable all TWL RTC module interrupts.
* Sets status flag to free.
*/
static int twl_rtc_remove(struct platform_device *pdev)
{
/* leave rtc running, but disable irqs */
mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M);
if (twl_class_is_6030()) {
twl6030_interrupt_mask(TWL6030_RTC_INT_MASK,
REG_INT_MSK_LINE_A);
twl6030_interrupt_mask(TWL6030_RTC_INT_MASK,
REG_INT_MSK_STS_A);
}
return 0;
}
static void twl_rtc_shutdown(struct platform_device *pdev)
{
/* mask timer interrupts, but leave alarm interrupts on to enable
power-on when alarm is triggered */
mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M);
}
#ifdef CONFIG_PM_SLEEP
static unsigned char irqstat;
static int twl_rtc_suspend(struct device *dev)
{
irqstat = rtc_irq_bits;
mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M);
return 0;
}
static int twl_rtc_resume(struct device *dev)
{
set_rtc_irq_bit(irqstat);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(twl_rtc_pm_ops, twl_rtc_suspend, twl_rtc_resume);
#ifdef CONFIG_OF
static const struct of_device_id twl_rtc_of_match[] = {
{.compatible = "ti,twl4030-rtc", },
{ },
};
MODULE_DEVICE_TABLE(of, twl_rtc_of_match);
#endif
MODULE_ALIAS("platform:twl_rtc");
static struct platform_driver twl4030rtc_driver = {
.probe = twl_rtc_probe,
.remove = twl_rtc_remove,
.shutdown = twl_rtc_shutdown,
.driver = {
.owner = THIS_MODULE,
.name = "twl_rtc",
.pm = &twl_rtc_pm_ops,
.of_match_table = of_match_ptr(twl_rtc_of_match),
},
};
module_platform_driver(twl4030rtc_driver);
MODULE_AUTHOR("Texas Instruments, MontaVista Software");
MODULE_LICENSE("GPL");
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