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path: root/drivers/rtc/rtc-s35390a.c
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Diffstat (limited to 'drivers/rtc/rtc-s35390a.c')
-rw-r--r--drivers/rtc/rtc-s35390a.c157
1 files changed, 119 insertions, 38 deletions
diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c
index f40afdd0e5f5..5dab4665ca3b 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c
@@ -15,6 +15,7 @@
#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
@@ -34,10 +35,14 @@
#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
@@ -94,19 +99,63 @@ static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
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)
@@ -217,12 +266,12 @@ static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
- /* disable interrupt */
+ /* disable interrupt (which deasserts the irq line) */
err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
if (err < 0)
return err;
- /* clear pending interrupt, if any */
+ /* clear pending interrupt (in STATUS1 only), if any */
err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
if (err < 0)
return err;
@@ -242,6 +291,8 @@ static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
if (alm->time.tm_wday != -1)
buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
+ else
+ buf[S35390A_ALRM_BYTE_WDAY] = 0;
buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
alm->time.tm_hour) | 0x80;
@@ -269,23 +320,43 @@ static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
if (err < 0)
return err;
- if (bitrev8(sts) != S35390A_INT2_MODE_ALARM)
- return -EINVAL;
+ if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
+ /*
+ * When the alarm isn't enabled, the register to configure
+ * the alarm time isn't accessible.
+ */
+ alm->enabled = 0;
+ return 0;
+ } else {
+ alm->enabled = 1;
+ }
err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
if (err < 0)
return err;
/* This chip returns the bits of each byte in reverse order */
- for (i = 0; i < 3; ++i) {
+ for (i = 0; i < 3; ++i)
buf[i] = bitrev8(buf[i]);
- buf[i] &= ~0x80;
- }
- alm->time.tm_wday = bcd2bin(buf[S35390A_ALRM_BYTE_WDAY]);
- alm->time.tm_hour = s35390a_reg2hr(s35390a,
- buf[S35390A_ALRM_BYTE_HOURS]);
- alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS]);
+ /*
+ * B0 of the three matching registers is an enable flag. Iff it is set
+ * the configured value is used for matching.
+ */
+ if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
+ alm->time.tm_wday =
+ bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
+
+ if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
+ alm->time.tm_hour =
+ s35390a_reg2hr(s35390a,
+ buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
+
+ if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
+ alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
+
+ /* alarm triggers always at s=0 */
+ alm->time.tm_sec = 0;
dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
__func__, alm->time.tm_min, alm->time.tm_hour,
@@ -327,11 +398,11 @@ static struct i2c_driver s35390a_driver;
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;
@@ -360,29 +431,35 @@ static int s35390a_probe(struct i2c_client *client,
}
}
- 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);
@@ -395,6 +472,10 @@ static int s35390a_probe(struct i2c_client *client,
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:
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 11:21:39 +0100