linux-kernel - Re: [PATCH v4 1/2] rtc: m48t59: Use platform

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <13fdfef9-4187-43d8-a8b9-ab091d6f952f@gaisler.com>
Date: Fri, 15 Nov 2024 16:49:46 +0100
From: Andreas Larsson <andreas@...sler.com>
To: Finn Thain <fthain@...ux-m68k.org>, "David S. Miller"
 <davem@...emloft.net>, Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: Daniel Palmer <daniel@...f.com>, Michael Pavone <pavone@...rodev.com>,
 linux-m68k@...ts.linux-m68k.org, linux-rtc@...r.kernel.org,
 sparclinux@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/2] rtc: m48t59: Use platform_data struct for year
 offset value

On 2024-11-12 23:32, Finn Thain wrote:
> Instead of hard-coded values and ifdefs, store the year offset in the
> platform_data struct.
> 
> Tested-by: Daniel Palmer <daniel@...f.com>
> Reviewed-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> Signed-off-by: Finn Thain <fthain@...ux-m68k.org>
> ---
> David, Andreas - with your acknowledgement, I will ask Alexandre to merge
> this.
> ---
> I tested this for regressions using qemu-system-sparc64.
> Also, Daniel tested the RTC functionality on his MVME147 system.
> 
> Changed since v2:
>  - Use an int for the year offset in struct m48t59_plat_data.
> 
> Changed since v3:
>  - Added reviewed-by tag from Geert.
> ---
>  arch/sparc/kernel/time_32.c |  1 +
>  arch/sparc/kernel/time_64.c |  1 +
>  drivers/rtc/rtc-m48t59.c    | 26 ++++----------------------
>  include/linux/rtc/m48t59.h  |  3 +++
>  4 files changed, 9 insertions(+), 22 deletions(-)
> 
> diff --git a/arch/sparc/kernel/time_32.c b/arch/sparc/kernel/time_32.c
> index 08bbdc458596..578fd0d49f30 100644
> --- a/arch/sparc/kernel/time_32.c
> +++ b/arch/sparc/kernel/time_32.c
> @@ -255,6 +255,7 @@ static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
>  static struct m48t59_plat_data m48t59_data = {
>  	.read_byte = mostek_read_byte,
>  	.write_byte = mostek_write_byte,
> +	.yy_offset = 68,
>  };
>  
>  /* resource is set at runtime */
> diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c
> index 60f1c8cc5363..b32f27f929d1 100644
> --- a/arch/sparc/kernel/time_64.c
> +++ b/arch/sparc/kernel/time_64.c
> @@ -544,6 +544,7 @@ static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
>  static struct m48t59_plat_data m48t59_data = {
>  	.read_byte	= mostek_read_byte,
>  	.write_byte	= mostek_write_byte,
> +	.yy_offset	= 68,
>  };
>  
>  static struct platform_device m48t59_rtc = {
> diff --git a/drivers/rtc/rtc-m48t59.c b/drivers/rtc/rtc-m48t59.c
> index 5d30ce8e13ca..4e608bc8bbd3 100644
> --- a/drivers/rtc/rtc-m48t59.c
> +++ b/drivers/rtc/rtc-m48t59.c
> @@ -71,7 +71,7 @@ static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
>  	/* Issue the READ command */
>  	M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
>  
> -	tm->tm_year	= bcd2bin(M48T59_READ(M48T59_YEAR));
> +	tm->tm_year	= bcd2bin(M48T59_READ(M48T59_YEAR)) + pdata->yy_offset;
>  	/* tm_mon is 0-11 */
>  	tm->tm_mon	= bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
>  	tm->tm_mday	= bcd2bin(M48T59_READ(M48T59_MDAY));
> @@ -82,10 +82,6 @@ static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
>  		dev_dbg(dev, "Century bit is enabled\n");
>  		tm->tm_year += 100;	/* one century */
>  	}
> -#ifdef CONFIG_SPARC
> -	/* Sun SPARC machines count years since 1968 */
> -	tm->tm_year += 68;
> -#endif
>  
>  	tm->tm_wday	= bcd2bin(val & 0x07);
>  	tm->tm_hour	= bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
> @@ -106,12 +102,7 @@ static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
>  	struct m48t59_private *m48t59 = dev_get_drvdata(dev);
>  	unsigned long flags;
>  	u8 val = 0;
> -	int year = tm->tm_year;
> -
> -#ifdef CONFIG_SPARC
> -	/* Sun SPARC machines count years since 1968 */
> -	year -= 68;
> -#endif
> +	int year = tm->tm_year - pdata->yy_offset;
>  
>  	dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
>  		year + 1900, tm->tm_mon, tm->tm_mday,
> @@ -162,11 +153,7 @@ static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
>  	/* Issue the READ command */
>  	M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
>  
> -	tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
> -#ifdef CONFIG_SPARC
> -	/* Sun SPARC machines count years since 1968 */
> -	tm->tm_year += 68;
> -#endif
> +	tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR)) + pdata->yy_offset;
>  	/* tm_mon is 0-11 */
>  	tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
>  
> @@ -197,12 +184,7 @@ static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
>  	struct rtc_time *tm = &alrm->time;
>  	u8 mday, hour, min, sec;
>  	unsigned long flags;
> -	int year = tm->tm_year;
> -
> -#ifdef CONFIG_SPARC
> -	/* Sun SPARC machines count years since 1968 */
> -	year -= 68;
> -#endif
> +	int year = tm->tm_year - pdata->yy_offset;
>  
>  	/* If no irq, we don't support ALARM */
>  	if (m48t59->irq == NO_IRQ)
> diff --git a/include/linux/rtc/m48t59.h b/include/linux/rtc/m48t59.h
> index 9465d5405fe2..373ba77071c6 100644
> --- a/include/linux/rtc/m48t59.h
> +++ b/include/linux/rtc/m48t59.h
> @@ -56,6 +56,9 @@ struct m48t59_plat_data {
>  	void __iomem *ioaddr;
>  	/* offset to RTC registers, automatically set according to the type */
>  	unsigned int offset;
> +
> +	/* YY digits (in RTC) are offset, i.e. year is 1900 + yy_offset + YY */
> +	int yy_offset;
>  };
>  
>  #endif /* _LINUX_RTC_M48T59_H_ */

Tested-by: Andreas Larsson <andreas@...sler.com>
Acked-by: Andreas Larsson <andreas@...sler.com>

Thanks,
Andreas