rtc-ds1307 cleanups
[linux-2.6.git] / drivers / rtc / rtc-ds1307.c
index 3f0f7b8..75e30c6 100644 (file)
  * setting the date and time), Linux can ignore the non-clock features.
  * That's a natural job for a factory or repair bench.
  *
+ * This is currently a simple no-alarms driver.  If your board has the
+ * alarm irq wired up on a ds1337 or ds1339, and you want to use that,
+ * then look at the rtc-rs5c372 driver for code to steal...
+ *
  * If the I2C "force" mechanism is used, we assume the chip is a ds1337.
  * (Much better would be board-specific tables of I2C devices, along with
  * the platform_data drivers would use to sort such issues out.)
  */
 enum ds_type {
        unknown = 0,
-       ds_1307,                /* or ds1338, ... */
-       ds_1337,                /* or ds1339, ... */
-       ds_1340,                /* or st m41t00, ... */
+       ds_1307,
+       ds_1337,
+       ds_1338,
+       ds_1339,
+       ds_1340,
+       m41t00,
        // rs5c372 too?  different address...
 };
 
@@ -56,11 +63,12 @@ I2C_CLIENT_INSMOD;
 #define DS1307_REG_YEAR                0x06    /* 00-99 */
 
 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
- * start at 7, and they differ a lot. Only control and status matter for RTC;
- * be careful using them.
+ * start at 7, and they differ a LOT. Only control and status matter for
+ * basic RTC date and time functionality; be careful using them.
  */
-#define DS1307_REG_CONTROL     0x07
+#define DS1307_REG_CONTROL     0x07            /* or ds1338 */
 #      define DS1307_BIT_OUT           0x80
+#      define DS1338_BIT_STOP          0x20
 #      define DS1307_BIT_SQWE          0x10
 #      define DS1307_BIT_RS1           0x02
 #      define DS1307_BIT_RS0           0x01
@@ -71,6 +79,13 @@ I2C_CLIENT_INSMOD;
 #      define DS1337_BIT_INTCN         0x04
 #      define DS1337_BIT_A2IE          0x02
 #      define DS1337_BIT_A1IE          0x01
+#define DS1340_REG_CONTROL     0x07
+#      define DS1340_BIT_OUT           0x80
+#      define DS1340_BIT_FT            0x40
+#      define DS1340_BIT_CALIB_SIGN    0x20
+#      define DS1340_M_CALIBRATION     0x1f
+#define DS1338_REG_FLAG                0x09
+#      define DS1338_BIT_OSF           0x80
 #define DS1337_REG_STATUS      0x0f
 #      define DS1337_BIT_OSF           0x80
 #      define DS1337_BIT_A2I           0x02
@@ -84,21 +99,63 @@ struct ds1307 {
        u8                      regs[8];
        enum ds_type            type;
        struct i2c_msg          msg[2];
-       struct i2c_client       client;
+       struct i2c_client       *client;
+       struct i2c_client       dev;
        struct rtc_device       *rtc;
 };
 
+struct chip_desc {
+       char                    name[9];
+       unsigned                nvram56:1;
+       unsigned                alarm:1;
+       enum ds_type            type;
+};
+
+static const struct chip_desc chips[] = { {
+       .name           = "ds1307",
+       .type           = ds_1307,
+       .nvram56        = 1,
+}, {
+       .name           = "ds1337",
+       .type           = ds_1337,
+       .alarm          = 1,
+}, {
+       .name           = "ds1338",
+       .type           = ds_1338,
+       .nvram56        = 1,
+}, {
+       .name           = "ds1339",
+       .type           = ds_1339,
+       .alarm          = 1,
+}, {
+       .name           = "ds1340",
+       .type           = ds_1340,
+}, {
+       .name           = "m41t00",
+       .type           = m41t00,
+}, };
+
+static inline const struct chip_desc *find_chip(const char *s)
+{
+       unsigned i;
+
+       for (i = 0; i < ARRAY_SIZE(chips); i++)
+               if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
+                       return &chips[i];
+       return NULL;
+}
 
 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 {
        struct ds1307   *ds1307 = dev_get_drvdata(dev);
        int             tmp;
 
-       /* read the RTC registers all at once */
+       /* read the RTC date and time registers all at once */
        ds1307->msg[1].flags = I2C_M_RD;
        ds1307->msg[1].len = 7;
 
-       tmp = i2c_transfer(ds1307->client.adapter, ds1307->msg, 2);
+       tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
+                       ds1307->msg, 2);
        if (tmp != 2) {
                dev_err(dev, "%s error %d\n", "read", tmp);
                return -EIO;
@@ -129,7 +186,8 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)
                t->tm_hour, t->tm_mday,
                t->tm_mon, t->tm_year, t->tm_wday);
 
-       return 0;
+       /* initial clock setting can be undefined */
+       return rtc_valid_tm(t);
 }
 
 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
@@ -170,7 +228,8 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
                "write", buf[0], buf[1], buf[2], buf[3],
                buf[4], buf[5], buf[6]);
 
-       result = i2c_transfer(ds1307->client.adapter, &ds1307->msg[1], 1);
+       result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
+                       &ds1307->msg[1], 1);
        if (result != 1) {
                dev_err(dev, "%s error %d\n", "write", tmp);
                return -EIO;
@@ -192,18 +251,34 @@ ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
        int                     err = -ENODEV;
        struct i2c_client       *client;
        int                     tmp;
+       const struct chip_desc  *chip;
 
        if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) {
                err = -ENOMEM;
                goto exit;
        }
 
-       client = &ds1307->client;
+       /* REVISIT:  pending driver model conversion, set up "client"
+        * ourselves, and use a hack to determine the RTC type (instead
+        * of reading the client->name we're given)
+        */
+       client = &ds1307->dev;
        client->addr = address;
        client->adapter = adapter;
        client->driver = &ds1307_driver;
-       client->flags = 0;
 
+       /* HACK: "force" implies "needs ds1337-style-oscillator setup", and
+        * that's the only kind of chip setup we'll know about.  Until the
+        * driver model conversion, here's where to add any board-specific
+        * code to say what kind of chip is present...
+        */
+       if (kind >= 0)
+               chip = find_chip("ds1337");
+       else
+               chip = find_chip("ds1307");
+       strlcpy(client->name, chip->name, I2C_NAME_SIZE);
+
+       ds1307->client = client;
        i2c_set_clientdata(client, ds1307);
 
        ds1307->msg[0].addr = client->addr;
@@ -216,14 +291,17 @@ ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
        ds1307->msg[1].len = sizeof(ds1307->regs);
        ds1307->msg[1].buf = ds1307->regs;
 
-       /* HACK: "force" implies "needs ds1337-style-oscillator setup" */
-       if (kind >= 0) {
+       ds1307->type = chip->type;
+
+       switch (ds1307->type) {
+       case ds_1337:
+       case ds_1339:
                ds1307->type = ds_1337;
 
                ds1307->reg_addr = DS1337_REG_CONTROL;
                ds1307->msg[1].len = 2;
 
-               tmp = i2c_transfer(client->adapter, ds1307->msg, 2);
+               tmp = i2c_transfer(adapter, ds1307->msg, 2);
                if (tmp != 2) {
                        pr_debug("read error %d\n", tmp);
                        err = -EIO;
@@ -236,16 +314,20 @@ ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
                /* oscillator is off; need to turn it on */
                if ((ds1307->regs[0] & DS1337_BIT_nEOSC)
                                || (ds1307->regs[1] & DS1337_BIT_OSF)) {
-                       printk(KERN_ERR "no ds1337 oscillator code\n");
+no_osc_start:
+                       printk(KERN_ERR "no %s oscillator code\n",
+                               chip->name);
                        goto exit_free;
                }
-       } else
-               ds1307->type = ds_1307;
+               break;
+       default:
+               break;
+       }
 
 read_rtc:
        /* read RTC registers */
 
-       tmp = i2c_transfer(client->adapter, ds1307->msg, 2);
+       tmp = i2c_transfer(adapter, ds1307->msg, 2);
        if (tmp != 2) {
                pr_debug("read error %d\n", tmp);
                err = -EIO;
@@ -257,20 +339,27 @@ read_rtc:
         * still a few values that are clearly out-of-range.
         */
        tmp = ds1307->regs[DS1307_REG_SECS];
-       if (tmp & DS1307_BIT_CH) {
-               if (ds1307->type && ds1307->type != ds_1307) {
-                       pr_debug("not a ds1307?\n");
-                       goto exit_free;
+       switch (ds1307->type) {
+       case ds_1307:
+       case ds_1338:
+       case m41t00:
+               if (tmp & DS1307_BIT_CH) {
+                       i2c_smbus_write_byte_data(client, 0, 0);
+                       dev_warn(&client->dev,
+                               "oscillator started; SET TIME!\n");
+                       goto read_rtc;
                }
-               ds1307->type = ds_1307;
-
-               /* this partial initialization should work for ds1307,
-                * ds1338, ds1340, st m41t00, and more.
-                */
-               dev_warn(&client->dev, "oscillator started; SET TIME!\n");
-               i2c_smbus_write_byte_data(client, 0, 0);
-               goto read_rtc;
+               break;
+       case ds_1340:
+               /* FIXME write code to start the oscillator */
+               if (tmp & DS1307_BIT_CH)
+                       goto no_osc_start;
+               break;
+       default:
+               break;
        }
+
+       tmp = ds1307->regs[DS1307_REG_SECS];
        tmp = BCD2BIN(tmp & 0x7f);
        if (tmp > 60)
                goto exit_free;
@@ -288,6 +377,9 @@ read_rtc:
 
        /* force into in 24 hour mode (most chips) or
         * disable century bit (ds1340)
+        *
+        * REVISIT forcing 24 hour mode can prevent multi-master
+        * configs from sharing this RTC ... don't do this.
         */
        tmp = ds1307->regs[DS1307_REG_HOUR];
        if (tmp & (1 << 6)) {
@@ -300,26 +392,6 @@ read_rtc:
                                BIN2BCD(tmp));
        }
 
-       /* FIXME chips like 1337 can generate alarm irqs too; those are
-        * worth exposing through the API (especially when the irq is
-        * wakeup-capable).
-        */
-
-       switch (ds1307->type) {
-       case unknown:
-               strlcpy(client->name, "unknown", I2C_NAME_SIZE);
-               break;
-       case ds_1307:
-               strlcpy(client->name, "ds1307", I2C_NAME_SIZE);
-               break;
-       case ds_1337:
-               strlcpy(client->name, "ds1337", I2C_NAME_SIZE);
-               break;
-       case ds_1340:
-               strlcpy(client->name, "ds1340", I2C_NAME_SIZE);
-               break;
-       }
-
        /* Tell the I2C layer a new client has arrived */
        if ((err = i2c_attach_client(client)))
                goto exit_free;