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linux/drivers/rtc/rtc-da9063.c
Steve Twiss 77535acedc rtc: da9063: fix access ordering error during RTC interrupt at system power on 
This fix alters the ordering of the IRQ and device registrations in the RTC
driver probe function. This change will apply to the RTC driver that supports
both DA9063 and DA9062 PMICs.

A problem could occur with the existing RTC driver if:

A system is started from a cold boot using the PMIC RTC IRQ to initiate a
power on operation. For instance, if an RTC alarm is used to start a
platform from power off.
The existing driver IRQ is requested before the device has been properly
registered.
i.e.
    ret = devm_request_threaded_irq()
comes before
    rtc->rtc_dev = devm_rtc_device_register();

In this case, the interrupt can be called before the device has been
registered and the handler can be called immediately. The IRQ handler
da9063_alarm_event() contains the function call

    rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);

which in turn tries to access the unavailable rtc->rtc_dev.

The fix is to reorder the functions inside the RTC probe. The IRQ is
requested after the RTC device resource has been registered so that
get_irq_byname is the last thing to happen.

Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2015-12-20 13:39:29 +01:00

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/* rtc-da9063.c - Real time clock device driver for DA9063
* Copyright (C) 2013-2015 Dialog Semiconductor Ltd.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/mfd/da9062/registers.h>
#include <linux/mfd/da9063/registers.h>
#include <linux/mfd/da9063/core.h>
#define YEARS_TO_DA9063(year) ((year) - 100)
#define MONTHS_TO_DA9063(month) ((month) + 1)
#define YEARS_FROM_DA9063(year) ((year) + 100)
#define MONTHS_FROM_DA9063(month) ((month) - 1)
enum {
RTC_SEC = 0,
RTC_MIN = 1,
RTC_HOUR = 2,
RTC_DAY = 3,
RTC_MONTH = 4,
RTC_YEAR = 5,
RTC_DATA_LEN
};
struct da9063_compatible_rtc_regmap {
/* REGS */
int rtc_enable_reg;
int rtc_enable_32k_crystal_reg;
int rtc_alarm_secs_reg;
int rtc_alarm_year_reg;
int rtc_count_secs_reg;
int rtc_count_year_reg;
int rtc_event_reg;
/* MASKS */
int rtc_enable_mask;
int rtc_crystal_mask;
int rtc_event_alarm_mask;
int rtc_alarm_on_mask;
int rtc_alarm_status_mask;
int rtc_tick_on_mask;
int rtc_ready_to_read_mask;
int rtc_count_sec_mask;
int rtc_count_min_mask;
int rtc_count_hour_mask;
int rtc_count_day_mask;
int rtc_count_month_mask;
int rtc_count_year_mask;
/* ALARM CONFIG */
int rtc_data_start;
int rtc_alarm_len;
};
struct da9063_compatible_rtc {
struct rtc_device *rtc_dev;
struct rtc_time alarm_time;
struct regmap *regmap;
const struct da9063_compatible_rtc_regmap *config;
bool rtc_sync;
};
static const struct da9063_compatible_rtc_regmap da9063_ad_regs = {
/* REGS */
.rtc_enable_reg = DA9063_REG_CONTROL_E,
.rtc_alarm_secs_reg = DA9063_AD_REG_ALARM_MI,
.rtc_alarm_year_reg = DA9063_AD_REG_ALARM_Y,
.rtc_count_secs_reg = DA9063_REG_COUNT_S,
.rtc_count_year_reg = DA9063_REG_COUNT_Y,
.rtc_event_reg = DA9063_REG_EVENT_A,
/* MASKS */
.rtc_enable_mask = DA9063_RTC_EN,
.rtc_crystal_mask = DA9063_CRYSTAL,
.rtc_enable_32k_crystal_reg = DA9063_REG_EN_32K,
.rtc_event_alarm_mask = DA9063_E_ALARM,
.rtc_alarm_on_mask = DA9063_ALARM_ON,
.rtc_alarm_status_mask = DA9063_ALARM_STATUS_ALARM |
DA9063_ALARM_STATUS_TICK,
.rtc_tick_on_mask = DA9063_TICK_ON,
.rtc_ready_to_read_mask = DA9063_RTC_READ,
.rtc_count_sec_mask = DA9063_COUNT_SEC_MASK,
.rtc_count_min_mask = DA9063_COUNT_MIN_MASK,
.rtc_count_hour_mask = DA9063_COUNT_HOUR_MASK,
.rtc_count_day_mask = DA9063_COUNT_DAY_MASK,
.rtc_count_month_mask = DA9063_COUNT_MONTH_MASK,
.rtc_count_year_mask = DA9063_COUNT_YEAR_MASK,
/* ALARM CONFIG */
.rtc_data_start = RTC_MIN,
.rtc_alarm_len = RTC_DATA_LEN - 1,
};
static const struct da9063_compatible_rtc_regmap da9063_bb_regs = {
/* REGS */
.rtc_enable_reg = DA9063_REG_CONTROL_E,
.rtc_alarm_secs_reg = DA9063_BB_REG_ALARM_S,
.rtc_alarm_year_reg = DA9063_BB_REG_ALARM_Y,
.rtc_count_secs_reg = DA9063_REG_COUNT_S,
.rtc_count_year_reg = DA9063_REG_COUNT_Y,
.rtc_event_reg = DA9063_REG_EVENT_A,
/* MASKS */
.rtc_enable_mask = DA9063_RTC_EN,
.rtc_crystal_mask = DA9063_CRYSTAL,
.rtc_enable_32k_crystal_reg = DA9063_REG_EN_32K,
.rtc_event_alarm_mask = DA9063_E_ALARM,
.rtc_alarm_on_mask = DA9063_ALARM_ON,
.rtc_alarm_status_mask = DA9063_ALARM_STATUS_ALARM |
DA9063_ALARM_STATUS_TICK,
.rtc_tick_on_mask = DA9063_TICK_ON,
.rtc_ready_to_read_mask = DA9063_RTC_READ,
.rtc_count_sec_mask = DA9063_COUNT_SEC_MASK,
.rtc_count_min_mask = DA9063_COUNT_MIN_MASK,
.rtc_count_hour_mask = DA9063_COUNT_HOUR_MASK,
.rtc_count_day_mask = DA9063_COUNT_DAY_MASK,
.rtc_count_month_mask = DA9063_COUNT_MONTH_MASK,
.rtc_count_year_mask = DA9063_COUNT_YEAR_MASK,
/* ALARM CONFIG */
.rtc_data_start = RTC_SEC,
.rtc_alarm_len = RTC_DATA_LEN,
};
static const struct da9063_compatible_rtc_regmap da9062_aa_regs = {
/* REGS */
.rtc_enable_reg = DA9062AA_CONTROL_E,
.rtc_alarm_secs_reg = DA9062AA_ALARM_S,
.rtc_alarm_year_reg = DA9062AA_ALARM_Y,
.rtc_count_secs_reg = DA9062AA_COUNT_S,
.rtc_count_year_reg = DA9062AA_COUNT_Y,
.rtc_event_reg = DA9062AA_EVENT_A,
/* MASKS */
.rtc_enable_mask = DA9062AA_RTC_EN_MASK,
.rtc_crystal_mask = DA9062AA_CRYSTAL_MASK,
.rtc_enable_32k_crystal_reg = DA9062AA_EN_32K,
.rtc_event_alarm_mask = DA9062AA_M_ALARM_MASK,
.rtc_alarm_on_mask = DA9062AA_ALARM_ON_MASK,
.rtc_alarm_status_mask = (0x02 << 6),
.rtc_tick_on_mask = DA9062AA_TICK_ON_MASK,
.rtc_ready_to_read_mask = DA9062AA_RTC_READ_MASK,
.rtc_count_sec_mask = DA9062AA_COUNT_SEC_MASK,
.rtc_count_min_mask = DA9062AA_COUNT_MIN_MASK,
.rtc_count_hour_mask = DA9062AA_COUNT_HOUR_MASK,
.rtc_count_day_mask = DA9062AA_COUNT_DAY_MASK,
.rtc_count_month_mask = DA9062AA_COUNT_MONTH_MASK,
.rtc_count_year_mask = DA9062AA_COUNT_YEAR_MASK,
/* ALARM CONFIG */
.rtc_data_start = RTC_SEC,
.rtc_alarm_len = RTC_DATA_LEN,
};
static const struct of_device_id da9063_compatible_reg_id_table[] = {
{ .compatible = "dlg,da9063-rtc", .data = &da9063_bb_regs },
{ .compatible = "dlg,da9062-rtc", .data = &da9062_aa_regs },
{ },
};
MODULE_DEVICE_TABLE(of, da9063_compatible_reg_id_table);
static void da9063_data_to_tm(u8 *data, struct rtc_time *tm,
struct da9063_compatible_rtc *rtc)
{
const struct da9063_compatible_rtc_regmap *config = rtc->config;
tm->tm_sec = data[RTC_SEC] & config->rtc_count_sec_mask;
tm->tm_min = data[RTC_MIN] & config->rtc_count_min_mask;
tm->tm_hour = data[RTC_HOUR] & config->rtc_count_hour_mask;
tm->tm_mday = data[RTC_DAY] & config->rtc_count_day_mask;
tm->tm_mon = MONTHS_FROM_DA9063(data[RTC_MONTH] &
config->rtc_count_month_mask);
tm->tm_year = YEARS_FROM_DA9063(data[RTC_YEAR] &
config->rtc_count_year_mask);
}
static void da9063_tm_to_data(struct rtc_time *tm, u8 *data,
struct da9063_compatible_rtc *rtc)
{
const struct da9063_compatible_rtc_regmap *config = rtc->config;
data[RTC_SEC] &= ~config->rtc_count_sec_mask;
data[RTC_SEC] |= tm->tm_sec & config->rtc_count_sec_mask;
data[RTC_MIN] &= ~config->rtc_count_min_mask;
data[RTC_MIN] |= tm->tm_min & config->rtc_count_min_mask;
data[RTC_HOUR] &= ~config->rtc_count_hour_mask;
data[RTC_HOUR] |= tm->tm_hour & config->rtc_count_hour_mask;
data[RTC_DAY] &= ~config->rtc_count_day_mask;
data[RTC_DAY] |= tm->tm_mday & config->rtc_count_day_mask;
data[RTC_MONTH] &= ~config->rtc_count_month_mask;
data[RTC_MONTH] |= MONTHS_TO_DA9063(tm->tm_mon) &
config->rtc_count_month_mask;
data[RTC_YEAR] &= ~config->rtc_count_year_mask;
data[RTC_YEAR] |= YEARS_TO_DA9063(tm->tm_year) &
config->rtc_count_year_mask;
}
static int da9063_rtc_stop_alarm(struct device *dev)
{
struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
const struct da9063_compatible_rtc_regmap *config = rtc->config;
return regmap_update_bits(rtc->regmap,
config->rtc_alarm_year_reg,
config->rtc_alarm_on_mask,
0);
}
static int da9063_rtc_start_alarm(struct device *dev)
{
struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
const struct da9063_compatible_rtc_regmap *config = rtc->config;
return regmap_update_bits(rtc->regmap,
config->rtc_alarm_year_reg,
config->rtc_alarm_on_mask,
config->rtc_alarm_on_mask);
}
static int da9063_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
const struct da9063_compatible_rtc_regmap *config = rtc->config;
unsigned long tm_secs;
unsigned long al_secs;
u8 data[RTC_DATA_LEN];
int ret;
ret = regmap_bulk_read(rtc->regmap,
config->rtc_count_secs_reg,
data, RTC_DATA_LEN);
if (ret < 0) {
dev_err(dev, "Failed to read RTC time data: %d\n", ret);
return ret;
}
if (!(data[RTC_SEC] & config->rtc_ready_to_read_mask)) {
dev_dbg(dev, "RTC not yet ready to be read by the host\n");
return -EINVAL;
}
da9063_data_to_tm(data, tm, rtc);
rtc_tm_to_time(tm, &tm_secs);
rtc_tm_to_time(&rtc->alarm_time, &al_secs);
/* handle the rtc synchronisation delay */
if (rtc->rtc_sync == true && al_secs - tm_secs == 1)
memcpy(tm, &rtc->alarm_time, sizeof(struct rtc_time));
else
rtc->rtc_sync = false;
return rtc_valid_tm(tm);
}
static int da9063_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
const struct da9063_compatible_rtc_regmap *config = rtc->config;
u8 data[RTC_DATA_LEN];
int ret;
da9063_tm_to_data(tm, data, rtc);
ret = regmap_bulk_write(rtc->regmap,
config->rtc_count_secs_reg,
data, RTC_DATA_LEN);
if (ret < 0)
dev_err(dev, "Failed to set RTC time data: %d\n", ret);
return ret;
}
static int da9063_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
const struct da9063_compatible_rtc_regmap *config = rtc->config;
u8 data[RTC_DATA_LEN];
int ret;
unsigned int val;
data[RTC_SEC] = 0;
ret = regmap_bulk_read(rtc->regmap,
config->rtc_alarm_secs_reg,
&data[config->rtc_data_start],
config->rtc_alarm_len);
if (ret < 0)
return ret;
da9063_data_to_tm(data, &alrm->time, rtc);
alrm->enabled = !!(data[RTC_YEAR] & config->rtc_alarm_on_mask);
ret = regmap_read(rtc->regmap,
config->rtc_event_reg,
&val);
if (ret < 0)
return ret;
if (val & config->rtc_event_alarm_mask)
alrm->pending = 1;
else
alrm->pending = 0;
return 0;
}
static int da9063_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct da9063_compatible_rtc *rtc = dev_get_drvdata(dev);
const struct da9063_compatible_rtc_regmap *config = rtc->config;
u8 data[RTC_DATA_LEN];
int ret;
da9063_tm_to_data(&alrm->time, data, rtc);
ret = da9063_rtc_stop_alarm(dev);
if (ret < 0) {
dev_err(dev, "Failed to stop alarm: %d\n", ret);
return ret;
}
ret = regmap_bulk_write(rtc->regmap,
config->rtc_alarm_secs_reg,
&data[config->rtc_data_start],
config->rtc_alarm_len);
if (ret < 0) {
dev_err(dev, "Failed to write alarm: %d\n", ret);
return ret;
}
da9063_data_to_tm(data, &rtc->alarm_time, rtc);
if (alrm->enabled) {
ret = da9063_rtc_start_alarm(dev);
if (ret < 0) {
dev_err(dev, "Failed to start alarm: %d\n", ret);
return ret;
}
}
return ret;
}
static int da9063_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
if (enabled)
return da9063_rtc_start_alarm(dev);
else
return da9063_rtc_stop_alarm(dev);
}
static irqreturn_t da9063_alarm_event(int irq, void *data)
{
struct da9063_compatible_rtc *rtc = data;
const struct da9063_compatible_rtc_regmap *config = rtc->config;
regmap_update_bits(rtc->regmap,
config->rtc_alarm_year_reg,
config->rtc_alarm_on_mask,
0);
rtc->rtc_sync = true;
rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops da9063_rtc_ops = {
.read_time = da9063_rtc_read_time,
.set_time = da9063_rtc_set_time,
.read_alarm = da9063_rtc_read_alarm,
.set_alarm = da9063_rtc_set_alarm,
.alarm_irq_enable = da9063_rtc_alarm_irq_enable,
};
static int da9063_rtc_probe(struct platform_device *pdev)
{
struct da9063_compatible_rtc *rtc;
const struct da9063_compatible_rtc_regmap *config;
const struct of_device_id *match;
int irq_alarm;
u8 data[RTC_DATA_LEN];
int ret;
if (!pdev->dev.of_node)
return -ENXIO;
match = of_match_node(da9063_compatible_reg_id_table,
pdev->dev.of_node);
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
rtc->config = match->data;
if (of_device_is_compatible(pdev->dev.of_node, "dlg,da9063-rtc")) {
struct da9063 *chip = dev_get_drvdata(pdev->dev.parent);
if (chip->variant_code == PMIC_DA9063_AD)
rtc->config = &da9063_ad_regs;
}
rtc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
if (!rtc->regmap) {
dev_warn(&pdev->dev, "Parent regmap unavailable.\n");
return -ENXIO;
}
config = rtc->config;
ret = regmap_update_bits(rtc->regmap,
config->rtc_enable_reg,
config->rtc_enable_mask,
config->rtc_enable_mask);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to enable RTC\n");
return ret;
}
ret = regmap_update_bits(rtc->regmap,
config->rtc_enable_32k_crystal_reg,
config->rtc_crystal_mask,
config->rtc_crystal_mask);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to run 32kHz oscillator\n");
return ret;
}
ret = regmap_update_bits(rtc->regmap,
config->rtc_alarm_secs_reg,
config->rtc_alarm_status_mask,
0);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to access RTC alarm register\n");
return ret;
}
ret = regmap_update_bits(rtc->regmap,
config->rtc_alarm_secs_reg,
DA9063_ALARM_STATUS_ALARM,
DA9063_ALARM_STATUS_ALARM);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to access RTC alarm register\n");
return ret;
}
ret = regmap_update_bits(rtc->regmap,
config->rtc_alarm_year_reg,
config->rtc_tick_on_mask,
0);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to disable TICKs\n");
return ret;
}
data[RTC_SEC] = 0;
ret = regmap_bulk_read(rtc->regmap,
config->rtc_alarm_secs_reg,
&data[config->rtc_data_start],
config->rtc_alarm_len);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to read initial alarm data: %d\n",
ret);
return ret;
}
platform_set_drvdata(pdev, rtc);
rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, DA9063_DRVNAME_RTC,
&da9063_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc_dev))
return PTR_ERR(rtc->rtc_dev);
da9063_data_to_tm(data, &rtc->alarm_time, rtc);
rtc->rtc_sync = false;
irq_alarm = platform_get_irq_byname(pdev, "ALARM");
ret = devm_request_threaded_irq(&pdev->dev, irq_alarm, NULL,
da9063_alarm_event,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
"ALARM", rtc);
if (ret)
dev_err(&pdev->dev, "Failed to request ALARM IRQ %d: %d\n",
irq_alarm, ret);
return ret;
}
static struct platform_driver da9063_rtc_driver = {
.probe = da9063_rtc_probe,
.driver = {
.name = DA9063_DRVNAME_RTC,
.of_match_table = da9063_compatible_reg_id_table,
},
};
module_platform_driver(da9063_rtc_driver);
MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
MODULE_DESCRIPTION("Real time clock device driver for Dialog DA9063");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DA9063_DRVNAME_RTC);
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