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rtc: ds1307: add support for watchdog timer on ds1388

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The DS1388 variant has watchdog timer capabilities. When using a DS1388
and having enabled CONFIG_WATCHDOG_CORE register a watchdog device for
the DS1388.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200330025500.6991-1-chris.packham@alliedtelesis.co.nz
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Chris Packham 2020-03-30 15:55:00 +13:00 committed by Alexandre Belloni
parent 06c4e103bf
commit fd90d48db0
2 changed files with 116 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
drivers/rtc/Kconfig
View file

@ -238,6 +238,7 @@ config RTC_DRV_AS3722
config RTC_DRV_DS1307
tristate "Dallas/Maxim DS1307/37/38/39/40/41, ST M41T00, EPSON RX-8025, ISL12057"
select REGMAP_I2C
select WATCHDOG_CORE if WATCHDOG
help
If you say yes here you get support for various compatible RTC
chips (often with battery backup) connected with I2C. This driver

115
drivers/rtc/rtc-ds1307.c
View file

@ -22,6 +22,7 @@
#include <linux/hwmon-sysfs.h>
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>
/*
* We can't determine type by probing, but if we expect pre-Linux code
@ -144,8 +145,15 @@ enum ds_type {
# define M41TXX_BIT_CALIB_SIGN BIT(5)
# define M41TXX_M_CALIBRATION GENMASK(4, 0)
#define DS1388_REG_WDOG_HUN_SECS 0x08
#define DS1388_REG_WDOG_SECS 0x09
#define DS1388_REG_FLAG 0x0b
# define DS1388_BIT_WF BIT(6)
# define DS1388_BIT_OSF BIT(7)
#define DS1388_REG_CONTROL 0x0c
# define DS1388_BIT_RST BIT(0)
# define DS1388_BIT_WDE BIT(1)
/* negative offset step is -2.034ppm */
#define M41TXX_NEG_OFFSET_STEP_PPB 2034
/* positive offset step is +4.068ppm */
@ -854,6 +862,72 @@ static int m41txx_rtc_set_offset(struct device *dev, long offset)
ctrl_reg);
}
#ifdef CONFIG_WATCHDOG_CORE
static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
{
struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
u8 regs[2];
int ret;
ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
DS1388_BIT_WF, 0);
if (ret)
return ret;
ret = regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
DS1388_BIT_WDE | DS1388_BIT_RST, 0);
if (ret)
return ret;
/*
* watchdog timeouts are measured in seconds. So ignore hundredths of
* seconds field.
*/
regs[0] = 0;
regs[1] = bin2bcd(wdt_dev->timeout);
ret = regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
sizeof(regs));
if (ret)
return ret;
return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
DS1388_BIT_WDE | DS1388_BIT_RST,
DS1388_BIT_WDE | DS1388_BIT_RST);
}
static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
{
struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
DS1388_BIT_WDE | DS1388_BIT_RST, 0);
}
static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
{
struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
u8 regs[2];
return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
sizeof(regs));
}
static int ds1388_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int val)
{
struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
u8 regs[2];
wdt_dev->timeout = val;
regs[0] = 0;
regs[1] = bin2bcd(wdt_dev->timeout);
return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
sizeof(regs));
}
#endif
static const struct rtc_class_ops rx8130_rtc_ops = {
.read_time = ds1307_get_time,
.set_time = ds1307_set_time,
@ -1576,6 +1650,46 @@ static void ds1307_clks_register(struct ds1307 *ds1307)
#endif /* CONFIG_COMMON_CLK */
#ifdef CONFIG_WATCHDOG_CORE
static const struct watchdog_info ds1388_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "DS1388 watchdog",
};
static const struct watchdog_ops ds1388_wdt_ops = {
.owner = THIS_MODULE,
.start = ds1388_wdt_start,
.stop = ds1388_wdt_stop,
.ping = ds1388_wdt_ping,
.set_timeout = ds1388_wdt_set_timeout,
};
static void ds1307_wdt_register(struct ds1307 *ds1307)
{
struct watchdog_device *wdt;
if (ds1307->type != ds_1388)
return;
wdt = devm_kzalloc(ds1307->dev, sizeof(*wdt), GFP_KERNEL);
wdt->info = &ds1388_wdt_info;
wdt->ops = &ds1388_wdt_ops;
wdt->timeout = 99;
wdt->max_timeout = 99;
wdt->min_timeout = 1;
watchdog_init_timeout(wdt, 0, ds1307->dev);
watchdog_set_drvdata(wdt, ds1307);
devm_watchdog_register_device(ds1307->dev, wdt);
}
#else
static void ds1307_wdt_register(struct ds1307 *ds1307)
{
}
#endif /* CONFIG_WATCHDOG_CORE */
static const struct regmap_config regmap_config = {
.reg_bits = 8,
.val_bits = 8,
@ -1865,6 +1979,7 @@ static int ds1307_probe(struct i2c_client *client,
ds1307_hwmon_register(ds1307);
ds1307_clks_register(ds1307);
ds1307_wdt_register(ds1307);
return 0;