summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-ds1307.c
diff options
context:
space:
mode:
authorChris Packham <chris.packham@alliedtelesis.co.nz>2020-03-30 15:55:00 +1300
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2020-04-01 12:33:44 +0200
commitfd90d48db0377d4a5a6786ce19d33185c2cbe029 (patch)
treebb1f92ab58939aa0b14b44ddff4947b22b741af1 /drivers/rtc/rtc-ds1307.c
parent06c4e103bf8a292d19697e670fb05a36a197e9da (diff)
downloadlinux-fd90d48db0377d4a5a6786ce19d33185c2cbe029.tar.gz
linux-fd90d48db0377d4a5a6786ce19d33185c2cbe029.tar.bz2
linux-fd90d48db0377d4a5a6786ce19d33185c2cbe029.zip
rtc: ds1307: add support for watchdog timer on ds1388
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>
Diffstat (limited to 'drivers/rtc/rtc-ds1307.c')
-rw-r--r--drivers/rtc/rtc-ds1307.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 31a38d468378..fad042118862 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -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;