[RFC] rtc: use sign_extend8 instead of manual conversion

From: Martin Kepplinger
Date: Mon Jan 12 2015 - 12:28:48 EST


Example change, using new sign_extend functions.
---
drivers/rtc/rtc-x1205.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-x1205.c b/drivers/rtc/rtc-x1205.c
index b1de58e..3ec0b95 100644
--- a/drivers/rtc/rtc-x1205.c
+++ b/drivers/rtc/rtc-x1205.c
@@ -22,6 +22,7 @@
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/module.h>
+#include <linux/bitops.h>

#define DRV_VERSION "1.0.8"

@@ -366,8 +367,7 @@ static int x1205_get_atrim(struct i2c_client *client, int *trim)
* perform sign extension. The formula is
* Catr = (atr * 0.25pF) + 11.00pF.
*/
- if (atr & 0x20)
- atr |= 0xC0;
+ atr = sign_extend8(atr, 5);

dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);

--
2.1.4

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