rtc-ds1307 becomes new-style i2c driver

Convert the rtc-ds1307 driver into a "new style" driver.

Also improve probe() checks:  be more correct about switching out of
AM/PM mode, and issue a (debug) diagnostic when failing due to bogus
register values.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Andrew Victor <andrew@sanpeople.com>
Cc: Bill Gatliff <bgat@billgatliff.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 53 insertions, 75 deletions

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 5306a1a5b873..5158a625671f 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -27,13 +27,8 @@
  * 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,
         ds_1337,
         ds_1338,
@@ -43,11 +38,6 @@ enum ds_type {
         // rs5c372 too?  different address...
 };
 
-static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
-
-I2C_CLIENT_INSMOD;
-
-
 
 /* RTC registers don't differ much, except for the century flag */
 #define DS1307_REG_SECS         0x00    /* 00-59 */
@@ -55,6 +45,8 @@ I2C_CLIENT_INSMOD;
 #       define DS1340_BIT_nEOSC         0x80
 #define DS1307_REG_MIN          0x01    /* 00-59 */
 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
+#       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
+#       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
 #define DS1307_REG_WDAY         0x03    /* 01-07 */
@@ -252,39 +244,27 @@ static const struct rtc_class_ops ds13xx_rtc_ops = {
 
 static struct i2c_driver ds1307_driver;
 
-static int __devinit
-ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
+static int __devinit ds1307_probe(struct i2c_client *client)
 {
         struct ds1307           *ds1307;
         int                     err = -ENODEV;
-        struct i2c_client       *client;
         int                     tmp;
         const struct chip_desc  *chip;
+        struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 
-        if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) {
-                err = -ENOMEM;
-                goto exit;
+        chip = find_chip(client->name);
+        if (!chip) {
+                dev_err(&client->dev, "unknown chip type '%s'\n",
+                                client->name);
+                return -ENODEV;
         }
 
-        /* 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;
-
-        /* 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);
+        if (!i2c_check_functionality(adapter,
+                        I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+                return -EIO;
+
+        if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
+                return -ENOMEM;
 
         ds1307->client = client;
         i2c_set_clientdata(client, ds1307);
@@ -378,94 +358,92 @@ read_rtc:
                         goto read_rtc;
                 }
                 break;
-        default:
+        case ds_1337:
+        case ds_1339:
                 break;
         }
 
         tmp = ds1307->regs[DS1307_REG_SECS];
         tmp = BCD2BIN(tmp & 0x7f);
         if (tmp > 60)
-                goto exit_free;
+                goto exit_bad;
         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
         if (tmp > 60)
-                goto exit_free;
+                goto exit_bad;
 
         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
         if (tmp == 0 || tmp > 31)
-                goto exit_free;
+                goto exit_bad;
 
         tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
         if (tmp == 0 || tmp > 12)
-                goto exit_free;
+                goto exit_bad;
 
-        /* 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.
-         * The clock needs to be reset after changing it, too...
-         */
         tmp = ds1307->regs[DS1307_REG_HOUR];
-        if (tmp & (1 << 6)) {
-                if (tmp & (1 << 5))
-                        tmp = BCD2BIN(tmp & 0x1f) + 12;
-                else
-                        tmp = BCD2BIN(tmp);
+        switch (ds1307->type) {
+        case ds_1340:
+        case m41t00:
+                /* NOTE: ignores century bits; fix before deploying
+                 * systems that will run through year 2100.
+                 */
+                break;
+        default:
+                if (!(tmp & DS1307_BIT_12HR))
+                        break;
+
+                /* Be sure we're in 24 hour mode.  Multi-master systems
+                 * take note...
+                 */
+                tmp = BCD2BIN(tmp & 0x1f);
+                if (tmp == 12)
+                        tmp = 0;
+                if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
+                        tmp += 12;
                 i2c_smbus_write_byte_data(client,
                                 DS1307_REG_HOUR,
                                 BIN2BCD(tmp));
         }
 
-        /* Tell the I2C layer a new client has arrived */
-        if ((err = i2c_attach_client(client)))
-                goto exit_free;
-
         ds1307->rtc = rtc_device_register(client->name, &client->dev,
                                 &ds13xx_rtc_ops, THIS_MODULE);
         if (IS_ERR(ds1307->rtc)) {
                 err = PTR_ERR(ds1307->rtc);
                 dev_err(&client->dev,
                         "unable to register the class device\n");
-                goto exit_detach;
+                goto exit_free;
         }
 
         return 0;
 
-exit_detach:
-        i2c_detach_client(client);
+exit_bad:
+        dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
+                        "bogus register",
+                        ds1307->regs[0], ds1307->regs[1],
+                        ds1307->regs[2], ds1307->regs[3],
+                        ds1307->regs[4], ds1307->regs[5],
+                        ds1307->regs[6]);
+
 exit_free:
         kfree(ds1307);
-exit:
         return err;
 }
 
-static int __devinit
-ds1307_attach_adapter(struct i2c_adapter *adapter)
-{
-        if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
-                return 0;
-        return i2c_probe(adapter, &addr_data, ds1307_detect);
-}
-
-static int __devexit ds1307_detach_client(struct i2c_client *client)
+static int __devexit ds1307_remove(struct i2c_client *client)
 {
-        int             err;
         struct ds1307   *ds1307 = i2c_get_clientdata(client);
 
         rtc_device_unregister(ds1307->rtc);
-        if ((err = i2c_detach_client(client)))
-                return err;
         kfree(ds1307);
         return 0;
 }
 
 static struct i2c_driver ds1307_driver = {
         .driver = {
-                .name   = "ds1307",
+                .name   = "rtc-ds1307",
                 .owner  = THIS_MODULE,
         },
-        .attach_adapter = ds1307_attach_adapter,
-        .detach_client  = __devexit_p(ds1307_detach_client),
+        .probe          = ds1307_probe,
+        .remove         = __devexit_p(ds1307_remove),
 };
 
 static int __init ds1307_init(void)