drivers/rtc/rtc-s35390a.c: add wakealarm support for rtc-s35390A rtc chip

Add basic get/set alarm support for the Seiko Instruments S-35390A.  The
chip is used on the QNAP TS-219P+ NAS device.

Signed-off-by: Michael Langer <michael.brainbug.langer@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c
index cc5c5166b018..8a092325188d 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c
@@ -19,6 +19,8 @@
 #define S35390A_CMD_STATUS1     0
 #define S35390A_CMD_STATUS2     1
 #define S35390A_CMD_TIME1       2
+#define S35390A_CMD_TIME2       3
+#define S35390A_CMD_INT2_REG1   5
 
 #define S35390A_BYTE_YEAR       0
 #define S35390A_BYTE_MONTH      1
@@ -28,12 +30,23 @@
 #define S35390A_BYTE_MINS       5
 #define S35390A_BYTE_SECS       6
 
+#define S35390A_ALRM_BYTE_WDAY  0
+#define S35390A_ALRM_BYTE_HOURS 1
+#define S35390A_ALRM_BYTE_MINS  2
+
 #define S35390A_FLAG_POC        0x01
 #define S35390A_FLAG_BLD        0x02
 #define S35390A_FLAG_24H        0x40
 #define S35390A_FLAG_RESET      0x80
 #define S35390A_FLAG_TEST       0x01
 
+#define S35390A_INT2_MODE_MASK          0xF0
+
+#define S35390A_INT2_MODE_NOINTR        0x00
+#define S35390A_INT2_MODE_FREQ          0x10
+#define S35390A_INT2_MODE_ALARM         0x40
+#define S35390A_INT2_MODE_PMIN_EDG      0x20
+
 static const struct i2c_device_id s35390a_id[] = {
         { "s35390a", 0 },
         { }
@@ -193,6 +206,104 @@ static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
         return rtc_valid_tm(tm);
 }
 
+static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
+{
+        struct s35390a *s35390a = i2c_get_clientdata(client);
+        char buf[3], sts = 0;
+        int err, i;
+
+        dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
+                "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
+                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 */
+        err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
+        if (err < 0)
+                return err;
+
+        /* clear pending interrupt, if any */
+        err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
+        if (err < 0)
+                return err;
+
+        if (alm->enabled)
+                sts = S35390A_INT2_MODE_ALARM;
+        else
+                sts = S35390A_INT2_MODE_NOINTR;
+
+        /* This chip expects the bits of each byte to be in reverse order */
+        sts = bitrev8(sts);
+
+        /* set interupt mode*/
+        err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
+        if (err < 0)
+                return err;
+
+        if (alm->time.tm_wday != -1)
+                buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
+
+        buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
+                        alm->time.tm_hour) | 0x80;
+        buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
+
+        if (alm->time.tm_hour >= 12)
+                buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
+
+        for (i = 0; i < 3; ++i)
+                buf[i] = bitrev8(buf[i]);
+
+        err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
+                                                                sizeof(buf));
+
+        return err;
+}
+
+static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
+{
+        struct s35390a *s35390a = i2c_get_clientdata(client);
+        char buf[3], sts;
+        int i, err;
+
+        err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
+        if (err < 0)
+                return err;
+
+        if (bitrev8(sts) != S35390A_INT2_MODE_ALARM)
+                return -EINVAL;
+
+        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) {
+                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]);
+
+        dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
+                        __func__, alm->time.tm_min, alm->time.tm_hour,
+                        alm->time.tm_wday);
+
+        return 0;
+}
+
+static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        return s35390a_read_alarm(to_i2c_client(dev), alm);
+}
+
+static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        return s35390a_set_alarm(to_i2c_client(dev), alm);
+}
+
 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
         return s35390a_get_datetime(to_i2c_client(dev), tm);
@@ -206,6 +317,9 @@ static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 static const struct rtc_class_ops s35390a_rtc_ops = {
         .read_time      = s35390a_rtc_read_time,
         .set_time       = s35390a_rtc_set_time,
+        .set_alarm      = s35390a_rtc_set_alarm,
+        .read_alarm     = s35390a_rtc_read_alarm,
+
 };
 
 static struct i2c_driver s35390a_driver;
@@ -270,6 +384,8 @@ static int s35390a_probe(struct i2c_client *client,
         if (s35390a_get_datetime(client, &tm) < 0)
                 dev_warn(&client->dev, "clock needs to be set\n");
 
+        device_set_wakeup_capable(&client->dev, 1);
+
         s35390a->rtc = rtc_device_register(s35390a_driver.driver.name,
                                 &client->dev, &s35390a_rtc_ops, THIS_MODULE);