summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-wm831x.c
diff options
context:
space:
mode:
authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-06 18:48:31 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-06 18:48:31 +0200
commitc87985a3ce723995fc7b25e598238d67154108a1 (patch)
treee60def1b77c25c1d74180f62e8a5603f9826f209 /drivers/rtc/rtc-wm831x.c
parenttty: Fix race in tty release (diff)
parentLinux 3.6-rc1 (diff)
downloadlinux-c87985a3ce723995fc7b25e598238d67154108a1.tar.xz
linux-c87985a3ce723995fc7b25e598238d67154108a1.zip
Merge tty-next into 3.6-rc1
This handles the merge issue in: arch/um/drivers/line.c arch/um/drivers/line.h And resolves the duplicate patches that were in both trees do to the tty-next branch not getting merged into 3.6-rc1. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/rtc/rtc-wm831x.c')
-rw-r--r--drivers/rtc/rtc-wm831x.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-wm831x.c b/drivers/rtc/rtc-wm831x.c
index 59c6245e0421..ea5c6f857ca5 100644
--- a/drivers/rtc/rtc-wm831x.c
+++ b/drivers/rtc/rtc-wm831x.c
@@ -24,7 +24,7 @@
#include <linux/mfd/wm831x/core.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
-
+#include <linux/random.h>
/*
* R16416 (0x4020) - RTC Write Counter
@@ -96,6 +96,26 @@ struct wm831x_rtc {
unsigned int alarm_enabled:1;
};
+static void wm831x_rtc_add_randomness(struct wm831x *wm831x)
+{
+ int ret;
+ u16 reg;
+
+ /*
+ * The write counter contains a pseudo-random number which is
+ * regenerated every time we set the RTC so it should be a
+ * useful per-system source of entropy.
+ */
+ ret = wm831x_reg_read(wm831x, WM831X_RTC_WRITE_COUNTER);
+ if (ret >= 0) {
+ reg = ret;
+ add_device_randomness(&reg, sizeof(reg));
+ } else {
+ dev_warn(wm831x->dev, "Failed to read RTC write counter: %d\n",
+ ret);
+ }
+}
+
/*
* Read current time and date in RTC
*/
@@ -431,6 +451,8 @@ static int wm831x_rtc_probe(struct platform_device *pdev)
alm_irq, ret);
}
+ wm831x_rtc_add_randomness(wm831x);
+
return 0;
err: