rtc: rtc-m41t80.c: add support for the ST M41T65 RTC

Add support for M41T65 Real Time Clock chip.

The main differences I see between the M41T65 and M41T80 are that:

1) The M41T65 watchdog timer has three bits controlling resolution
   (versus two for the M41T80).

2) There is no register 0x13 for controlling square-wave output.

Signed-off-by: Steven A. Falco <sfalco@harris.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 1a94596..f660ef3 100644 (file)
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -220,22 +220,22 @@ config RTC_DRV_PCF8583
          will be called rtc-pcf8583.
 
 config RTC_DRV_M41T80
-       tristate "ST M41T80/81/82/83/84/85/87"
+       tristate "ST M41T65/M41T80/81/82/83/84/85/87"
        help
-         If you say Y here you will get support for the
-         ST M41T80 RTC chips series. Currently following chips are
-         supported: M41T80, M41T81, M41T82, M41T83, M41ST84, M41ST85
-         and M41ST87.
+         If you say Y here you will get support for the ST M41T60
+         and M41T80 RTC chips series. Currently, the following chips are
+         supported: M41T65, M41T80, M41T81, M41T82, M41T83, M41ST84,
+         M41ST85, and M41ST87.
 
          This driver can also be built as a module. If so, the module
          will be called rtc-m41t80.
 
 config RTC_DRV_M41T80_WDT
-       bool "ST M41T80 series RTC watchdog timer"
+       bool "ST M41T65/M41T80 series RTC watchdog timer"
        depends on RTC_DRV_M41T80
        help
          If you say Y here you will get support for the
-         watchdog timer in ST M41T80 RTC chips series.
+         watchdog timer in the ST M41T60 and M41T80 RTC chips series.
 
 config RTC_DRV_TWL92330
        boolean "TI TWL92330/Menelaus"

diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c
index 24bc168..470fb2d 100644 (file)
--- a/drivers/rtc/rtc-m41t80.c
+++ b/drivers/rtc/rtc-m41t80.c
@@ -56,21 +56,27 @@
 #define M41T80_ALHOUR_HT       (1 << 6)        /* HT: Halt Update Bit */
 #define M41T80_FLAGS_AF                (1 << 6)        /* AF: Alarm Flag Bit */
 #define M41T80_FLAGS_BATT_LOW  (1 << 4)        /* BL: Battery Low Bit */
+#define M41T80_WATCHDOG_RB2    (1 << 7)        /* RB: Watchdog resolution */
+#define M41T80_WATCHDOG_RB1    (1 << 1)        /* RB: Watchdog resolution */
+#define M41T80_WATCHDOG_RB0    (1 << 0)        /* RB: Watchdog resolution */
 
-#define M41T80_FEATURE_HT      (1 << 0)
-#define M41T80_FEATURE_BL      (1 << 1)
+#define M41T80_FEATURE_HT      (1 << 0)        /* Halt feature */
+#define M41T80_FEATURE_BL      (1 << 1)        /* Battery low indicator */
+#define M41T80_FEATURE_SQ      (1 << 2)        /* Squarewave feature */
+#define M41T80_FEATURE_WD      (1 << 3)        /* Extra watchdog resolution */
 
 #define DRV_VERSION "0.05"
 
 static const struct i2c_device_id m41t80_id[] = {
-       { "m41t80", 0 },
-       { "m41t81", M41T80_FEATURE_HT },
-       { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL },
-       { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL },
-       { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL },
-       { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL },
-       { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL },
-       { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL },
+       { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
+       { "m41t80", M41T80_FEATURE_SQ },
+       { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
+       { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
+       { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
+       { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
+       { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
+       { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
+       { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
        { }
 };
 MODULE_DEVICE_TABLE(i2c, m41t80_id);
@@ -386,8 +392,12 @@ static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
        struct i2c_client *client = to_i2c_client(dev);
+       struct m41t80_data *clientdata = i2c_get_clientdata(client);
        int val;
 
+       if (!(clientdata->features & M41T80_FEATURE_SQ))
+               return -EINVAL;
+
        val = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
        if (val < 0)
                return -EIO;
@@ -408,9 +418,13 @@ static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
                                const char *buf, size_t count)
 {
        struct i2c_client *client = to_i2c_client(dev);
+       struct m41t80_data *clientdata = i2c_get_clientdata(client);
        int almon, sqw;
        int val = simple_strtoul(buf, NULL, 0);
 
+       if (!(clientdata->features & M41T80_FEATURE_SQ))
+               return -EINVAL;
+
        if (val) {
                if (!is_power_of_2(val))
                        return -EINVAL;
@@ -499,6 +513,8 @@ static void wdt_ping(void)
                        .buf    = i2c_data,
                },
        };
+       struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
+
        i2c_data[0] = 0x09;             /* watchdog register */
 
        if (wdt_margin > 31)
@@ -509,6 +525,13 @@ static void wdt_ping(void)
                 */
                i2c_data[1] = wdt_margin<<2 | 0x82;
 
+       /*
+        * M41T65 has three bits for watchdog resolution.  Don't set bit 7, as
+        * that would be an invalid resolution.
+        */
+       if (clientdata->features & M41T80_FEATURE_WD)
+               i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
+
        i2c_transfer(save_client->adapter, msgs1, 1);
 }