rtc: add wakealarm support for rtc-s35390A rtc chip

Hello,

this patch will add get/set alarm functionality to QNAP TS-219P+ NAS. I have tested it against a debian wheezy kernel (3.2.23, armel) . After that I applied the patch against HEAD of linus master branch and compiled, not tested, successfully.

Regards
Michael

From: Michael Langer <[email protected]>
Date: Sun, 23 Sep 2012 08:27:24 +0200
Subject: [PATCH] rtc: add wakealarm support for rtc-s35390A rtc chip

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

---
 drivers/rtc/rtc-s35390a.c |  116
+++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)

index c9562ce..ef41e7e 100644
@@ -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 },
     { }

@@ -184,6 +197,104 @@ 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);
@@ -197,6 +308,9 @@ 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;
@@ -261,6 +375,8 @@ 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);

1.7.10.4