lkml.org 
[lkml]   [2007]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] Add support for the S-35390A RTC chip.
On Thu,  6 Dec 2007 22:10:27 +0000 Byron Bradley <byron.bbradley@gmail.com> wrote:

> This adds basic get/set time support for the Seiko Instruments
> S-35390A. This chip communicates using I2C and is used on the
> QNAP TS-109/TS-209 NAS devices.
>

A nice looking little driver.

> +static inline char reverse(char x)
> +{
> + x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa);
> + x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc);
> + return (x >> 4) | (x << 4);
> +}

Please take a peek in include/linux/bitrev.h ;)

(I worry about the handling of right-shift-of-negative-values
in your version, too).

Could you review and runtime test this please?

--- a/drivers/rtc/rtc-s35390a.c~rtc-add-support-for-the-s-35390a-rtc-chip-fix
+++ a/drivers/rtc/rtc-s35390a.c
@@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/i2c.h>
+#include <linux/bitrev.h>
#include <linux/bcd.h>

#define S35390A_CMD_STATUS1 0
@@ -121,13 +122,6 @@ static int s35390a_reg2hr(struct s35390a
return hour;
}

-static inline char reverse(char x)
-{
- x = ((x >> 1) & 0x55) | ((x << 1) & 0xaa);
- x = ((x >> 2) & 0x33) | ((x << 2) & 0xcc);
- return (x >> 4) | (x << 4);
-}
-
static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct s35390a *s35390a = i2c_get_clientdata(client);
@@ -149,7 +143,7 @@ static int s35390a_set_datetime(struct i

/* This chip expects the bits of each byte to be in reverse order */
for (i = 0; i < 7; ++i)
- buf[i] = reverse(buf[i]);
+ buf[i] = bitrev8(buf[i]);

err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));

@@ -168,7 +162,7 @@ static int s35390a_get_datetime(struct i

/* This chip returns the bits of each byte in reverse order */
for (i = 0; i < 7; ++i)
- buf[i] = reverse(buf[i]);
+ buf[i] = bitrev8(buf[i]);

tm->tm_sec = BCD2BIN(buf[S35390A_BYTE_SECS]);
tm->tm_min = BCD2BIN(buf[S35390A_BYTE_MINS]);
_


\
 
 \ /
  Last update: 2007-12-12 09:27    [W:0.096 / U:0.416 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site