#include <linux/bitrev.h>
#include <linux/bcd.h>
#include <linux/slab.h>
+#include <linux/delay.h>
#define S35390A_CMD_STATUS1 0
#define S35390A_CMD_STATUS2 1
#define S35390A_ALRM_BYTE_HOURS 1
#define S35390A_ALRM_BYTE_MINS 2
+/* flags for STATUS1 */
#define S35390A_FLAG_POC 0x01
#define S35390A_FLAG_BLD 0x02
+#define S35390A_FLAG_INT2 0x04
#define S35390A_FLAG_24H 0x40
#define S35390A_FLAG_RESET 0x80
+
+/* flag for STATUS2 */
#define S35390A_FLAG_TEST 0x01
#define S35390A_INT2_MODE_MASK 0xF0
return 0;
}
-static int s35390a_reset(struct s35390a *s35390a)
+/*
+ * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
+ * To keep the information if an irq is pending, pass the value read from
+ * STATUS1 to the caller.
+ */
+static int s35390a_reset(struct s35390a *s35390a, char *status1)
{
- char buf[1];
-
- if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0)
- return -EIO;
-
- if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD)))
+ char buf;
+ int ret;
+ unsigned initcount = 0;
+
+ ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
+ if (ret < 0)
+ return ret;
+
+ if (*status1 & S35390A_FLAG_POC)
+ /*
+ * Do not communicate for 0.5 seconds since the power-on
+ * detection circuit is in operation.
+ */
+ msleep(500);
+ else if (!(*status1 & S35390A_FLAG_BLD))
+ /*
+ * If both POC and BLD are unset everything is fine.
+ */
return 0;
- buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H);
- buf[0] &= 0xf0;
- return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
+ /*
+ * At least one of POC and BLD are set, so reinitialise chip. Keeping
+ * this information in the hardware to know later that the time isn't
+ * valid is unfortunately not possible because POC and BLD are cleared
+ * on read. So the reset is best done now.
+ *
+ * The 24H bit is kept over reset, so set it already here.
+ */
+initialize:
+ *status1 = S35390A_FLAG_24H;
+ buf = S35390A_FLAG_RESET | S35390A_FLAG_24H;
+ ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
+
+ if (ret < 0)
+ return ret;
+
+ ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
+ if (ret < 0)
+ return ret;
+
+ if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) {
+ /* Try up to five times to reset the chip */
+ if (initcount < 5) {
+ ++initcount;
+ goto initialize;
+ } else
+ return -EIO;
+ }
+
+ return 1;
}
static int s35390a_disable_test_mode(struct s35390a *s35390a)
char buf[3], sts;
int i, err;
+ /*
+ * initialize all members to -1 to signal the core that they are not
+ * defined by the hardware.
+ */
+ alm->time.tm_sec = -1;
+ alm->time.tm_min = -1;
+ alm->time.tm_hour = -1;
+ alm->time.tm_mday = -1;
+ alm->time.tm_mon = -1;
+ alm->time.tm_year = -1;
+ alm->time.tm_wday = -1;
+ alm->time.tm_yday = -1;
+ alm->time.tm_isdst = -1;
+
err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
if (err < 0)
return err;
static int s35390a_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
- int err;
+ int err, err_reset;
unsigned int i;
struct s35390a *s35390a;
struct rtc_time tm;
- char buf[1];
+ char buf, status1;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
err = -ENODEV;
}
}
- err = s35390a_reset(s35390a);
- if (err < 0) {
+ err_reset = s35390a_reset(s35390a, &status1);
+ if (err_reset < 0) {
+ err = err_reset;
dev_err(&client->dev, "error resetting chip\n");
goto exit_dummy;
}
- err = s35390a_disable_test_mode(s35390a);
- if (err < 0) {
- dev_err(&client->dev, "error disabling test mode\n");
- goto exit_dummy;
- }
-
- err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
- if (err < 0) {
- dev_err(&client->dev, "error checking 12/24 hour mode\n");
- goto exit_dummy;
- }
- if (buf[0] & S35390A_FLAG_24H)
+ if (status1 & S35390A_FLAG_24H)
s35390a->twentyfourhour = 1;
else
s35390a->twentyfourhour = 0;
- if (s35390a_get_datetime(client, &tm) < 0)
+ if (status1 & S35390A_FLAG_INT2) {
+ /* disable alarm (and maybe test mode) */
+ buf = 0;
+ err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
+ if (err < 0) {
+ dev_err(&client->dev, "error disabling alarm");
+ goto exit_dummy;
+ }
+ } else {
+ err = s35390a_disable_test_mode(s35390a);
+ if (err < 0) {
+ dev_err(&client->dev, "error disabling test mode\n");
+ goto exit_dummy;
+ }
+ }
+
+ if (err_reset > 0 || s35390a_get_datetime(client, &tm) < 0)
dev_warn(&client->dev, "clock needs to be set\n");
device_set_wakeup_capable(&client->dev, 1);
err = PTR_ERR(s35390a->rtc);
goto exit_dummy;
}
+
+ if (status1 & S35390A_FLAG_INT2)
+ rtc_update_irq(s35390a->rtc, 1, RTC_AF);
+
return 0;
exit_dummy: