Messages in this thread Patch in this message | | | Date | Wed, 12 Dec 2007 00:23:33 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] Add support for the S-35390A RTC chip. |
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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]); _
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