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
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -220,22 +220,22 @@
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
--- 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 @@
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 @@
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 @@
.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 @@
*/
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);
}