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Date: Tue, 17 Jul 2007 11:36:45 -0500
From: Scott Wood <scottwood@freescale.com>
To: Vitaly Bordug <vitb@kernel.crashing.org>
Subject: Re: [PATCH] POWERPC: Added RTC support for mpc8313RDB and utilize
	"clock-frequency"
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On Tue, Jul 17, 2007 at 04:49:13AM +0400, Vitaly Bordug wrote:
> +	np = of_find_node_by_type(NULL, "cpu");
> +	if (np != 0) {
> +		const unsigned int *fp =
> +			get_property(np, "clock-frequency", NULL);
> +		if (fp != 0)
> +			loops_per_jiffy = *fp / HZ;
> +		else
> +			loops_per_jiffy = 50000000 / HZ;
> +		of_node_put(np);
> +	}

This is not necessary.  It's only used for /proc/cpuinfo (delays are done
using tb_ticks_per_usec), and it'll be overwritten by the generic
calibrate_delay() anyway.

We should be removing this from board files that have it, not adding it
to ones that don't.

> +#if defined (CONFIG_SENSORS_DS1337) && defined (CONFIG_I2C)
> +
> +extern int ds1337_do_command(int id, int cmd, void *arg);
> +extern spinlock_t rtc_lock;
> +#define DS1337_GET_DATE		0
> +#define DS1337_SET_DATE		1
> +
> +static void mpc8313rdb_get_rtc_time(struct rtc_time *tm)
> +{
> +	int result;
> +
> +	result = ds1337_do_command(0, DS1337_GET_DATE, tm);
> +
> +	if (result == 0)
> +		result = mktime(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
> +}
> +
> +static int mpc8313rdb_set_rtc_time(struct rtc_time *tm)
> +{
> +	int result;
> +
> +	result = ds1337_do_command(0, DS1337_SET_DATE, tm);
> +
> +	return result;
> +}
> +
> +static int __init rtc_hookup(void)
> +{
> +	ppc_md.get_rtc_time = mpc8313rdb_get_rtc_time;
> +	ppc_md.set_rtc_time = mpc8313rdb_set_rtc_time;
> +	return 0;
> +}
> +late_initcall(rtc_hookup);
> +#endif

Please don't do this; drivers/i2c/chips/ds1337.c is deprecated.  You
should be using the RTC-class driver in drivers/rtc/rtc-ds1307.c, which
has a non-device-specific API that can be used.

The ppc_md RTC functions should really just go away, though -- setting
the clock on bootup can be done by generic code, and periodically
updating the RTC when using NTP can be done from userspace.

-Scott