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authorAvi Kivity <avi@redhat.com>2012-08-05 13:25:10 +0300
committerAvi Kivity <avi@redhat.com>2012-08-05 13:25:10 +0300
commitfe56097b23b1303b894eefd91582e4a64247d03f (patch)
tree4b3ab60eb19e8cfe2884e2da66dd4e4e25ae2274 /drivers/rtc/rtc-wm831x.c
parente115676e042f4d9268c6b6d8cb7dc962aa6cfd7d (diff)
parente7882d6c40874a5b5033ca85f7508a602a60b662 (diff)
Merge remote-tracking branch 'upstream' into next
- bring back critical fixes (esp. aa67f6096c19bc) - provide an updated base for development * upstream: (4334 commits) missed mnt_drop_write() in do_dentry_open() UBIFS: nuke pdflush from comments gfs2: nuke pdflush from comments drbd: nuke pdflush from comments nilfs2: nuke write_super from comments hfs: nuke write_super from comments vfs: nuke pdflush from comments jbd/jbd2: nuke write_super from comments btrfs: nuke pdflush from comments btrfs: nuke write_super from comments ext4: nuke pdflush from comments ext4: nuke write_super from comments ext3: nuke write_super from comments Documentation: fix the VM knobs descritpion WRT pdflush Documentation: get rid of write_super vfs: kill write_super and sync_supers ACPI processor: Fix tick_broadcast_mask online/offline regression ACPI: Only count valid srat memory structures ACPI: Untangle a return statement for better readability Linux 3.6-rc1 ... Signed-off-by: Avi Kivity <avi@redhat.com>
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: