From: Uwe Kleine-König uwe@kleine-koenig.org
This patch has been added to the stable tree. If you have any objections, please let us know.
===============
[ Upstream commit 3bd32722c827d00eafe8e6d5b83e9f3148ea7c7e ]
On some QNAP NAS devices the rtc can wake the machine. Several people noticed that once the machine was woken this way it fails to shut down. That's because the driver fails to acknowledge the interrupt and so it keeps active and restarts the machine immediatly after shutdown. See https://bugs.debian.org/794266 for a bug report.
Doing this correctly requires to interpret the INT2 flag of the first read of the STATUS1 register because this bit is cleared by read.
Note this is not maximally robust though because a pending irq isn't detected when the STATUS1 register was already read (and so INT2 is not set) but the irq was not disabled. But that is a hardware imposed problem that cannot easily be fixed by software.
Signed-off-by: Uwe Kleine-König uwe@kleine-koenig.org Signed-off-by: Alexandre Belloni alexandre.belloni@free-electrons.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/rtc/rtc-s35390a.c | 48 ++++++++++++++++++++++++++++++----------------- 1 file changed, 31 insertions(+), 17 deletions(-)
diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c index 6c90c9f48cab..d5b572266a72 100644 --- a/drivers/rtc/rtc-s35390a.c +++ b/drivers/rtc/rtc-s35390a.c @@ -35,10 +35,14 @@ #define S35390A_ALRM_BYTE_HOURS 1 #define S35390A_ALRM_BYTE_MINS 2
+/* flags for STATUS1 */ #define S35390A_FLAG_POC 0x01 #define S35390A_FLAG_BLD 0x02 +#define S35390A_FLAG_INT2 0x04 #define S35390A_FLAG_24H 0x40 #define S35390A_FLAG_RESET 0x80 + +/* flag for STATUS2 */ #define S35390A_FLAG_TEST 0x01
#define S35390A_INT2_MODE_MASK 0xF0 @@ -394,11 +398,11 @@ static struct i2c_driver s35390a_driver; static int s35390a_probe(struct i2c_client *client, const struct i2c_device_id *id) { - int err; + int err, err_reset; unsigned int i; struct s35390a *s35390a; struct rtc_time tm; - char buf[1], status1; + char buf, status1;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { err = -ENODEV; @@ -427,29 +431,35 @@ static int s35390a_probe(struct i2c_client *client, } }
- err = s35390a_reset(s35390a, &status1); - if (err < 0) { + err_reset = s35390a_reset(s35390a, &status1); + if (err_reset < 0) { + err = err_reset; dev_err(&client->dev, "error resetting chip\n"); goto exit_dummy; }
- err = s35390a_disable_test_mode(s35390a); - if (err < 0) { - dev_err(&client->dev, "error disabling test mode\n"); - goto exit_dummy; - } - - err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)); - if (err < 0) { - dev_err(&client->dev, "error checking 12/24 hour mode\n"); - goto exit_dummy; - } - if (buf[0] & S35390A_FLAG_24H) + if (status1 & S35390A_FLAG_24H) s35390a->twentyfourhour = 1; else s35390a->twentyfourhour = 0;
- if (s35390a_get_datetime(client, &tm) < 0) + if (status1 & S35390A_FLAG_INT2) { + /* disable alarm (and maybe test mode) */ + buf = 0; + err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1); + if (err < 0) { + dev_err(&client->dev, "error disabling alarm"); + goto exit_dummy; + } + } else { + err = s35390a_disable_test_mode(s35390a); + if (err < 0) { + dev_err(&client->dev, "error disabling test mode\n"); + goto exit_dummy; + } + } + + if (err_reset > 0 || s35390a_get_datetime(client, &tm) < 0) dev_warn(&client->dev, "clock needs to be set\n");
device_set_wakeup_capable(&client->dev, 1); @@ -462,6 +472,10 @@ static int s35390a_probe(struct i2c_client *client, err = PTR_ERR(s35390a->rtc); goto exit_dummy; } + + if (status1 & S35390A_FLAG_INT2) + rtc_update_irq(s35390a->rtc, 1, RTC_AF); + return 0;
exit_dummy: