[U-Boot] [PATCH] rtc: pcf8563: Make century compatible with Linux

[Benoît Thébaudeau]

On Fri, Jul 20, 2012 at 04:05:36 PM, Benoît Thébaudeau wrote:
> This driver uses the century bit of this RTC in the opposite way
> Linux does.
> From Linux's rtc-pcf8563.c:
> 	/*
> 	 * The meaning of MO_C bit varies by the chip type.
> 	 * From PCF8563 datasheet: this bit is toggled when the years
> 	 * register overflows from 99 to 00
> 	 *   0 indicates the century is 20xx
> 	 *   1 indicates the century is 19xx
> 	 * From RTC8564 datasheet: this bit indicates change of
> 	 * century. When the year digit data overflows from 99 to 00,
> 	 * this bit is set. By presetting it to 0 while still in the
> 	 * 20th century, it will be set in year 2000, ...
> 	 * There seems no reliable way to know how the system use this
> 	 * bit.  So let's do it heuristically, assuming we are live in
> 	 * 1970...2069.
> 	 */
> 
> As U-Boot's PCF8563 driver does not say it is supposed to support the
> RTC8564,
> make this driver compatible with Linux's by giving the opposite
> meaning to the
> century bit.
> 
> Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
> Cc: Wolfgang Denk <wd at denx.de>
> ---
>  .../drivers/rtc/pcf8563.c                          |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git u-boot-66714b1.orig/drivers/rtc/pcf8563.c
> u-boot-66714b1/drivers/rtc/pcf8563.c
> index 339e5f6..a028533 100644
> --- u-boot-66714b1.orig/drivers/rtc/pcf8563.c
> +++ u-boot-66714b1/drivers/rtc/pcf8563.c
> @@ -72,7 +72,7 @@ int rtc_get (struct rtc_time *tmp)
>  	tmp->tm_hour = bcd2bin (hour & 0x3F);
>  	tmp->tm_mday = bcd2bin (mday & 0x3F);
>  	tmp->tm_mon  = bcd2bin (mon_cent & 0x1F);
> -	tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
> +	tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 1900 : 2000);
>  	tmp->tm_wday = bcd2bin (wday & 0x07);
>  	tmp->tm_yday = 0;
>  	tmp->tm_isdst= 0;
> @@ -94,7 +94,7 @@ int rtc_set (struct rtc_time *tmp)
>  
>  	rtc_write (0x08, bin2bcd(tmp->tm_year % 100));
>  
> -	century = (tmp->tm_year >= 2000) ? 0x80 : 0;
> +	century = (tmp->tm_year >= 2000) ? 0 : 0x80;
>  	rtc_write (0x07, bin2bcd(tmp->tm_mon) | century);
>  
>  	rtc_write (0x06, bin2bcd(tmp->tm_wday));
> 

Ping?

Benoît