diff options
| author | John W. Linville <linville@tuxdriver.com> | 2012-09-07 15:07:55 -0400 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2012-09-07 15:07:55 -0400 |
| commit | fac805f8c198092de9a2842efd7f5022e2937b18 (patch) | |
| tree | 7557809c373f97a343c427d8fded0696060394ce /drivers/rtc/rtc-wm831x.c | |
| parent | 2461c7d60f9f3821274e4acf9019cba8b82c94b5 (diff) | |
| parent | f10723841e624c0726c70356b31d91befed01dd6 (diff) | |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless
Diffstat (limited to 'drivers/rtc/rtc-wm831x.c')
| -rw-r--r-- | drivers/rtc/rtc-wm831x.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-wm831x.c b/drivers/rtc/rtc-wm831x.c index 59c6245e042..ea5c6f857ca 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(®, 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: |