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acrn-kernel/drivers/rtc/rtc-cpcap.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Motorola CPCAP PMIC RTC driver
*
* Based on cpcap-regulator.c from Motorola Linux kernel tree
* Copyright (C) 2009 Motorola, Inc.
*
* Rewritten for mainline kernel
* - use DT
* - use regmap
* - use standard interrupt framework
* - use managed device resources
* - remove custom "secure clock daemon" helpers
*
* Copyright (C) 2017 Sebastian Reichel <sre@kernel.org>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/err.h>
#include <linux/regmap.h>
#include <linux/mfd/motorola-cpcap.h>
#include <linux/slab.h>
#include <linux/sched.h>
#define SECS_PER_DAY 86400
#define DAY_MASK 0x7FFF
#define TOD1_MASK 0x00FF
#define TOD2_MASK 0x01FF
struct cpcap_time {
int day;
int tod1;
int tod2;
};
struct cpcap_rtc {
struct regmap *regmap;
struct rtc_device *rtc_dev;
u16 vendor;
int alarm_irq;
bool alarm_enabled;
int update_irq;
bool update_enabled;
};
static void cpcap2rtc_time(struct rtc_time *rtc, struct cpcap_time *cpcap)
{
unsigned long int tod;
unsigned long int time;
tod = (cpcap->tod1 & TOD1_MASK) | ((cpcap->tod2 & TOD2_MASK) << 8);
time = tod + ((cpcap->day & DAY_MASK) * SECS_PER_DAY);
rtc_time64_to_tm(time, rtc);
}
static void rtc2cpcap_time(struct cpcap_time *cpcap, struct rtc_time *rtc)
{
unsigned long time;
time = rtc_tm_to_time64(rtc);
cpcap->day = time / SECS_PER_DAY;
time %= SECS_PER_DAY;
cpcap->tod2 = (time >> 8) & TOD2_MASK;
cpcap->tod1 = time & TOD1_MASK;
}
static int cpcap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct cpcap_rtc *rtc = dev_get_drvdata(dev);
if (rtc->alarm_enabled == enabled)
return 0;
if (enabled)
enable_irq(rtc->alarm_irq);
else
disable_irq(rtc->alarm_irq);
rtc->alarm_enabled = !!enabled;
return 0;
}
static int cpcap_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct cpcap_rtc *rtc;
struct cpcap_time cpcap_tm;
int temp_tod2;
int ret;
rtc = dev_get_drvdata(dev);
ret = regmap_read(rtc->regmap, CPCAP_REG_TOD2, &temp_tod2);
ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day);
ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD1, &cpcap_tm.tod1);
ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD2, &cpcap_tm.tod2);
if (temp_tod2 > cpcap_tm.tod2)
ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day);
if (ret) {
dev_err(dev, "Failed to read time\n");
return -EIO;
}
cpcap2rtc_time(tm, &cpcap_tm);
return 0;
}
static int cpcap_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct cpcap_rtc *rtc;
struct cpcap_time cpcap_tm;
int ret = 0;
rtc = dev_get_drvdata(dev);
rtc2cpcap_time(&cpcap_tm, tm);
if (rtc->alarm_enabled)
disable_irq(rtc->alarm_irq);
if (rtc->update_enabled)
disable_irq(rtc->update_irq);
if (rtc->vendor == CPCAP_VENDOR_ST) {
/* The TOD1 and TOD2 registers MUST be written in this order
* for the change to properly set.
*/
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
TOD1_MASK, cpcap_tm.tod1);
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2,
TOD2_MASK, cpcap_tm.tod2);
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY,
DAY_MASK, cpcap_tm.day);
} else {
/* Clearing the upper lower 8 bits of the TOD guarantees that
* the upper half of TOD (TOD2) will not increment for 0xFF RTC
* ticks (255 seconds). During this time we can safely write
* to DAY, TOD2, then TOD1 (in that order) and expect RTC to be
* synchronized to the exact time requested upon the final write
* to TOD1.
*/
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
TOD1_MASK, 0);
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY,
DAY_MASK, cpcap_tm.day);
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2,
TOD2_MASK, cpcap_tm.tod2);
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
TOD1_MASK, cpcap_tm.tod1);
}
if (rtc->update_enabled)
enable_irq(rtc->update_irq);
if (rtc->alarm_enabled)
enable_irq(rtc->alarm_irq);
return ret;
}
static int cpcap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct cpcap_rtc *rtc;
struct cpcap_time cpcap_tm;
int ret;
rtc = dev_get_drvdata(dev);
alrm->enabled = rtc->alarm_enabled;
ret = regmap_read(rtc->regmap, CPCAP_REG_DAYA, &cpcap_tm.day);
ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA2, &cpcap_tm.tod2);
ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA1, &cpcap_tm.tod1);
if (ret) {
dev_err(dev, "Failed to read time\n");
return -EIO;
}
cpcap2rtc_time(&alrm->time, &cpcap_tm);
return rtc_valid_tm(&alrm->time);
}
static int cpcap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct cpcap_rtc *rtc;
struct cpcap_time cpcap_tm;
int ret;
rtc = dev_get_drvdata(dev);
rtc2cpcap_time(&cpcap_tm, &alrm->time);
if (rtc->alarm_enabled)
disable_irq(rtc->alarm_irq);
ret = regmap_update_bits(rtc->regmap, CPCAP_REG_DAYA, DAY_MASK,
cpcap_tm.day);
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA2, TOD2_MASK,
cpcap_tm.tod2);
ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA1, TOD1_MASK,
cpcap_tm.tod1);
if (!ret) {
enable_irq(rtc->alarm_irq);
rtc->alarm_enabled = true;
}
return ret;
}
static const struct rtc_class_ops cpcap_rtc_ops = {
.read_time = cpcap_rtc_read_time,
.set_time = cpcap_rtc_set_time,
.read_alarm = cpcap_rtc_read_alarm,
.set_alarm = cpcap_rtc_set_alarm,
.alarm_irq_enable = cpcap_rtc_alarm_irq_enable,
};
static irqreturn_t cpcap_rtc_alarm_irq(int irq, void *data)
{
struct cpcap_rtc *rtc = data;
rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
return IRQ_HANDLED;
}
static irqreturn_t cpcap_rtc_update_irq(int irq, void *data)
{
struct cpcap_rtc *rtc = data;
rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF);
return IRQ_HANDLED;
}
static int cpcap_rtc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct cpcap_rtc *rtc;
int err;
rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
rtc->regmap = dev_get_regmap(dev->parent, NULL);
if (!rtc->regmap)
return -ENODEV;
platform_set_drvdata(pdev, rtc);
rtc->rtc_dev = devm_rtc_allocate_device(dev);
if (IS_ERR(rtc->rtc_dev))
return PTR_ERR(rtc->rtc_dev);
rtc->rtc_dev->ops = &cpcap_rtc_ops;
rtc->rtc_dev->range_max = (timeu64_t) (DAY_MASK + 1) * SECS_PER_DAY - 1;
err = cpcap_get_vendor(dev, rtc->regmap, &rtc->vendor);
if (err)
return err;
rtc->alarm_irq = platform_get_irq(pdev, 0);
err = devm_request_threaded_irq(dev, rtc->alarm_irq, NULL,
cpcap_rtc_alarm_irq,
IRQF_TRIGGER_NONE | IRQF_ONESHOT,
"rtc_alarm", rtc);
if (err) {
dev_err(dev, "Could not request alarm irq: %d\n", err);
return err;
}
disable_irq(rtc->alarm_irq);
/* Stock Android uses the 1 Hz interrupt for "secure clock daemon",
* which is not supported by the mainline kernel. The mainline kernel
* does not use the irq at the moment, but we explicitly request and
* disable it, so that its masked and does not wake up the processor
* every second.
*/
rtc->update_irq = platform_get_irq(pdev, 1);
err = devm_request_threaded_irq(dev, rtc->update_irq, NULL,
cpcap_rtc_update_irq,
IRQF_TRIGGER_NONE | IRQF_ONESHOT,
"rtc_1hz", rtc);
if (err) {
dev_err(dev, "Could not request update irq: %d\n", err);
return err;
}
disable_irq(rtc->update_irq);
err = device_init_wakeup(dev, 1);
if (err) {
dev_err(dev, "wakeup initialization failed (%d)\n", err);
/* ignore error and continue without wakeup support */
}
return devm_rtc_register_device(rtc->rtc_dev);
}
static const struct of_device_id cpcap_rtc_of_match[] = {
{ .compatible = "motorola,cpcap-rtc", },
{},
};
MODULE_DEVICE_TABLE(of, cpcap_rtc_of_match);
static struct platform_driver cpcap_rtc_driver = {
.probe = cpcap_rtc_probe,
.driver = {
.name = "cpcap-rtc",
.of_match_table = cpcap_rtc_of_match,
},
};
module_platform_driver(cpcap_rtc_driver);
MODULE_ALIAS("platform:cpcap-rtc");
MODULE_DESCRIPTION("CPCAP RTC driver");
MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
MODULE_LICENSE("GPL");
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