[PATCH] rtc: fix potential race condition and remove build errors

From: Raghavendra Ganiga
Date: Mon May 19 2014 - 11:58:58 EST


this patch fixes the following build errors reported by kbuild test
robot by selecting REGMAP_SPI in Kconfig file

>drivers/built-in.o: In function `ds1343_probe':
>rtc-ds1343.c:(.text+0x1baf8f): undefined reference to `devm_regmap_init_spi'

also it avoids the potential race condition by avoiding
bailing out of driver in probe after registering with
rtc subsystem

also the set_alarm , read_alarm and
alarm_irq_enable returns error if irq registration
fails in probe

also the sysfs will not create entry for alarm if
irq registration fails in probe

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@xxxxxxxxx>
---
drivers/rtc/Kconfig | 1 +
drivers/rtc/rtc-ds1343.c | 38 ++++++++++++++++++++++++--------------
2 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index ae78408..0754f5c 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -574,6 +574,7 @@ config RTC_DRV_DS1305
will be called rtc-ds1305.

config RTC_DRV_DS1343
+ select REGMAP_SPI
tristate "Dallas/Maxim DS1343/DS1344"
help
If you say yes here you get support for the
diff --git a/drivers/rtc/rtc-ds1343.c b/drivers/rtc/rtc-ds1343.c
index 8ccc750..c371918 100644
--- a/drivers/rtc/rtc-ds1343.c
+++ b/drivers/rtc/rtc-ds1343.c
@@ -80,6 +80,7 @@ struct ds1343_priv {
struct regmap *map;
struct mutex mutex;
unsigned int irqen;
+ int irq;
int alarm_sec;
int alarm_min;
int alarm_hour;
@@ -262,28 +263,32 @@ static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);

static int ds1343_sysfs_register(struct device *dev)
{
+ struct ds1343_priv *priv = dev_get_drvdata(dev);
int err;

err = device_create_file(dev, &dev_attr_glitch_filter);
if (err)
return err;

- err = device_create_file(dev, &dev_attr_alarm_status);
+ err = device_create_file(dev, &dev_attr_trickle_charger);
if (err)
goto error1;

+ if (priv->irq <= 0)
+ return err;
+
err = device_create_file(dev, &dev_attr_alarm_mode);
if (err)
goto error2;

- err = device_create_file(dev, &dev_attr_trickle_charger);
+ err = device_create_file(dev, &dev_attr_alarm_status);
if (!err)
return err;

device_remove_file(dev, &dev_attr_alarm_mode);

error2:
- device_remove_file(dev, &dev_attr_alarm_status);
+ device_remove_file(dev, &dev_attr_trickle_charger);

error1:
device_remove_file(dev, &dev_attr_glitch_filter);
@@ -293,10 +298,16 @@ error1:

static void ds1343_sysfs_unregister(struct device *dev)
{
+ struct ds1343_priv *priv = dev_get_drvdata(dev);
+
device_remove_file(dev, &dev_attr_glitch_filter);
+ device_remove_file(dev, &dev_attr_trickle_charger);
+
+ if (priv->irq <= 0)
+ return;
+
device_remove_file(dev, &dev_attr_alarm_status);
device_remove_file(dev, &dev_attr_alarm_mode);
- device_remove_file(dev, &dev_attr_trickle_charger);
}

static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
@@ -415,11 +426,10 @@ static int ds1343_update_alarm(struct device *dev)
static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
- struct spi_device *spi = priv->spi;
int res = 0;
unsigned int stat;

- if (spi->irq <= 0)
+ if (priv->irq <= 0)
return -EINVAL;

mutex_lock(&priv->mutex);
@@ -450,10 +460,9 @@ out:
static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
- struct spi_device *spi = priv->spi;
int res = 0;

- if (spi->irq <= 0)
+ if (priv->irq <= 0)
return -EINVAL;

mutex_lock(&priv->mutex);
@@ -476,10 +485,9 @@ static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct ds1343_priv *priv = dev_get_drvdata(dev);
- struct spi_device *spi = priv->spi;
int res = 0;

- if (spi->irq <= 0)
+ if (priv->irq <= 0)
return -EINVAL;

mutex_lock(&priv->mutex);
@@ -593,18 +601,20 @@ static int ds1343_probe(struct spi_device *spi)
return PTR_ERR(priv->rtc);
}

- if (spi->irq >= 0) {
+ priv->irq = spi->irq;
+
+ if (priv->irq >= 0) {
res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
ds1343_thread,
IRQF_NO_SUSPEND | IRQF_ONESHOT,
"ds1343", priv);
if (res) {
+ priv->irq = -1;
dev_err(&spi->dev,
"unable to request irq for rtc ds1343\n");
- return res;
+ } else {
+ device_set_wakeup_capable(&spi->dev, 1);
}
-
- device_set_wakeup_capable(&spi->dev, 1);
}

res = ds1343_sysfs_register(&spi->dev);
--
1.8.3.2

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