From patchwork Tue Jan 25 04:53:31 2011
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Subject: [2/2] rtc: tps6586x: fix error in tick calculations.
Date: Mon, 24 Jan 2011 18:53:31 -0000
From: Varun Wadekar <vwadekar@nvidia.com>
X-Patchwork-Id: 80316
Message-Id: <4D3E574B.4070700@nvidia.com>
To: <rtc-linux@googlegroups.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>, "linux-tegra@vger.kernel.org"
 <linux-tegra@vger.kernel.org>, Andy Ritger <ARitger@nvidia.com>, Stephen
 Warren <swarren@nvidia.com>, Bharat Nihalani <bnihalani@nvidia.com>,
 Varun Wadekar <vwadekar@nvidia.com>

This patch depends on patch 1:

----
    rtc: tps6586x: fix error in tick calculations.

    when converting from seconds to ticks using a shift
    operator, the most significant bits were being lost
    due to seconds being a 32-bit value and ticks being
    a 64-bit value. a hard cast was added to avoid this
    loss.

    Signed-off-by: Lowell Dennis <ldennis@nvidia.com>

     buff[2] = (ticks >> 16) & 0xff;
@@ -148,7 +148,7 @@ static int tps6586x_rtc_set_alarm(struct device
*dev, struct rtc_wkalrm *alrm)
     }

     seconds -= rtc->epoch_start;
-    ticks = (seconds << 10) & 0xffffff;
+    ticks = (unsigned long long)seconds << 10;

     buff[0] = (ticks >> 16) & 0xff;
     buff[1] = (ticks >> 8) & 0xff;

nvpublic


diff --git a/drivers/rtc/rtc-tps6586x.c b/drivers/rtc/rtc-tps6586x.c
index 9ab93cb..ca6138b 100644
--- a/drivers/rtc/rtc-tps6586x.c
+++ b/drivers/rtc/rtc-tps6586x.c
@@ -95,7 +95,7 @@ static int tps6586x_rtc_set_time(struct device *dev,
struct rtc_time *tm)

     seconds -= rtc->epoch_start;

-    ticks = seconds << 10;
+    ticks = (unsigned long long)seconds << 10;
     buff[0] = (ticks >> 32) & 0xff;
     buff[1] = (ticks >> 24) & 0xff;