diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0354-rtc-ds1307-ensure-that-any-pending-alarm-is-cleared-.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0354-rtc-ds1307-ensure-that-any-pending-alarm-is-cleared-.patch | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0354-rtc-ds1307-ensure-that-any-pending-alarm-is-cleared-.patch b/target/linux/brcm2708/patches-4.4/0354-rtc-ds1307-ensure-that-any-pending-alarm-is-cleared-.patch new file mode 100644 index 0000000000..49d7b33f83 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0354-rtc-ds1307-ensure-that-any-pending-alarm-is-cleared-.patch @@ -0,0 +1,58 @@ +From 82be650e97522260a9694ae56dc3475f40c4240e Mon Sep 17 00:00:00 2001 +From: Nicolas Boullis <nboullis@debian.org> +Date: Sun, 10 Apr 2016 13:23:05 +0200 +Subject: [PATCH 354/423] rtc: ds1307: ensure that any pending alarm is cleared + before a new alarm is enabled +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +If a previously-set alarm was disabled and then triggered, it may still +be pending when a new alarm is configured. + +Then, if the alarm is enabled before the pending alarm is cleared, then +an interrupt is immediately raised. + +Unfortunately, when the alarm is cleared and enabled during the same I²C +block write, the chip (at least the DS1339 I have) considers that the +alarm is enabled before it is cleared, and raises an interrupt. + +This patch ensures that the pending alarm is cleared before the alarm is +enabled. + +Signed-off-by: Nicolas Boullis <nboullis@debian.org> +Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> +--- + drivers/rtc/rtc-ds1307.c | 13 ++++++++----- + 1 file changed, 8 insertions(+), 5 deletions(-) + +--- a/drivers/rtc/rtc-ds1307.c ++++ b/drivers/rtc/rtc-ds1307.c +@@ -540,12 +540,8 @@ static int ds1337_set_alarm(struct devic + buf[5] = 0; + buf[6] = 0; + +- /* optionally enable ALARM1 */ ++ /* disable alarms */ + buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE); +- if (t->enabled) { +- dev_dbg(dev, "alarm IRQ armed\n"); +- buf[7] |= DS1337_BIT_A1IE; /* only ALARM1 is used */ +- } + buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I); + + ret = ds1307->write_block_data(client, +@@ -555,6 +551,13 @@ static int ds1337_set_alarm(struct devic + return ret; + } + ++ /* optionally enable ALARM1 */ ++ if (t->enabled) { ++ dev_dbg(dev, "alarm IRQ armed\n"); ++ buf[7] |= DS1337_BIT_A1IE; /* only ALARM1 is used */ ++ i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, buf[7]); ++ } ++ + return 0; + } + |