linux-kernel - Re: [PATCH] rtc: pcf85063: remove useless century handling

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Message-Id: <201603010929.19210.jbe@pengutronix.de>
Date:	Tue, 1 Mar 2016 09:29:19 +0100
From:	Juergen Borleis <jbe@...gutronix.de>
To:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Cc:	rtc-linux@...glegroups.com,
	Alessandro Zummo <a.zummo@...ertech.it>,
	linux-kernel@...r.kernel.org,
	Ulrich Ölmann <u.oelmann@...gutronix.de>
Subject: Re: [PATCH] rtc: pcf85063: remove useless century handling

On Wednesday 24 February 2016 00:05:28 Alexandre Belloni wrote:
> pcf85063_get_datetime() tries to handle a century bit but that bit is not
> documented and the final value is never used anywhere else in the kernel.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
> ---
>  drivers/rtc/rtc-pcf85063.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
> index c5db231f14de..2b3b99b094b5 100644
> --- a/drivers/rtc/rtc-pcf85063.c
> +++ b/drivers/rtc/rtc-pcf85063.c
> @@ -31,13 +31,10 @@
>  #define PCF85063_REG_MO			0x09
>  #define PCF85063_REG_YR			0x0A
>
> -#define PCF85063_MO_C			0x80 /* century */
> -
>  static struct i2c_driver pcf85063_driver;
>
>  struct pcf85063 {
>  	struct rtc_device *rtc;
> -	int c_polarity;	/* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
>  	int voltage_low; /* indicates if a low_voltage was detected */
>  };
>
> @@ -103,9 +100,6 @@ static int pcf85063_get_datetime(struct i2c_client
> *client, struct rtc_time *tm) tm->tm_year = bcd2bin(regs[6]);
>  	if (tm->tm_year < 70)
>  		tm->tm_year += 100;	/* assume we are in 1970...2069 */
> -	/* detect the polarity heuristically. see note above. */
> -	pcf85063->c_polarity = (regs[5] & PCF85063_MO_C) ?
> -		(tm->tm_year >= 100) : (tm->tm_year < 100);
>
>  	return rtc_valid_tm(tm);
>  }

Reviewed-by: Juergen Borleis <jbe@...gutronix.de>
Tested-by: Ulrich Ölmann <u.oelmann@...gutronix.de>

Regards,
Juergen