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rtc: rtc-m41t80.c: add support for the ST M41T65 RTC
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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>
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Steven A. Falco authored and Linus Torvalds committed Oct 16, 2008
1 parent 0327457 commit d3a126f
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Showing 2 changed files with 40 additions and 17 deletions.
14 changes: 7 additions & 7 deletions drivers/rtc/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand Down
43 changes: 33 additions & 10 deletions drivers/rtc/rtc-m41t80.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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)
Expand All @@ -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);
}

Expand Down

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