[i2c] [PATCH] i2c: Deprecate legacy RTC drivers

[James Chapman]

Regarding the ds1337 driver, it exports a public function, 
ds1337_do_command(), which is currently used by functions in 
arch/ppc/platforms/radstone_ppc7d.c. This code is used to provide 
implementations used by the ppc arch get_rtc_time() and set_rtc_time() 
platform hooks. If the rtc subsystem now provides a better way to hook 
up these functions, the radstone_ppc7d code could be changed to use it 
instead of ds1337_do_command(), thereby allowing the old ds1337 driver 
to be removed.

Perhaps the radstone_ppc7d platform code should use rtc_read_time() and 
rtc_set_time() instead? Is it possible for platform code to obtain the 
rtc's struct class_device which are needed by those calls?

-- 
James Chapman
Katalix Systems Ltd
http://www.katalix.com
Catalysts for your Embedded Linux software development

Jean Delvare wrote:
> We have a new RTC subsystem with better drivers.
> 
> Legacy driver status:
> * ds1337: The DS1337 and DS1339 are now supported by the rtc-ds1307
>   driver, so it looks to me like we could even delete the ds1337
>   driver right away.
> * ds1374: No support in the RTC subsystem as far as I can see. If
>   DS1374 support is still needed, this driver needs to be ported to
>   the RTC subsystem.
> * m41t00: The M41T00 itself appears to be supported by the rtc-ds1307
>   driver, however the old driver also supports the M41T81 and M41T85,
>   while the new driver seemingly doesn't. So I guess the rtc-ds1307
>   driver needs to be extended before we can remove the m41t00 driver.
> 
> Signed-off-by: Jean Delvare <khali at linux-fr.org>
> Cc: Alessandro Zummo <a.zummo at towertech.it>
> Cc: Mark A. Greer <mgreer at mvista.com>
> Cc: James Chapman <jchapman at katalix.com>
> Cc: Randy Vinson <rvinson at mvista.com>
> ---
>  Documentation/feature-removal-schedule.txt |    7 +++++++
>  drivers/i2c/chips/Kconfig                  |   14 +++++++++++---
>  2 files changed, 18 insertions(+), 3 deletions(-)
> 
> --- linux-2.6.21-git.orig/drivers/i2c/chips/Kconfig	2007-05-11 09:00:44.000000000 +0200
> +++ linux-2.6.21-git/drivers/i2c/chips/Kconfig	2007-05-11 09:15:54.000000000 +0200
> @@ -5,7 +5,7 @@
>  menu "Miscellaneous I2C Chip support"
>  
>  config SENSORS_DS1337
> -	tristate "Dallas Semiconductor DS1337 and DS1339 Real Time Clock"
> +	tristate "Dallas DS1337 and DS1339 Real Time Clock (DEPRECATED)"
>  	depends on EXPERIMENTAL
>  	help
>  	  If you say yes here you get support for Dallas Semiconductor
> @@ -14,8 +14,11 @@ config SENSORS_DS1337
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called ds1337.
>  
> +	  This driver is deprecated and will be dropped soon. Use
> +	  rtc-ds1307 instead.
> +
>  config SENSORS_DS1374
> -	tristate "Maxim/Dallas Semiconductor DS1374 Real Time Clock"
> +	tristate "Dallas DS1374 Real Time Clock (DEPRECATED)"
>  	depends on EXPERIMENTAL
>  	help
>  	  If you say yes here you get support for Dallas Semiconductor
> @@ -24,6 +27,8 @@ config SENSORS_DS1374
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called ds1374.
>  
> +	  This driver is deprecated and will be dropped soon.
> +
>  config SENSORS_EEPROM
>  	tristate "EEPROM reader"
>  	depends on EXPERIMENTAL
> @@ -101,7 +106,7 @@ config TPS65010
>  	  will be called tps65010.
>  
>  config SENSORS_M41T00
> -	tristate "ST M41T00 RTC chip"
> +	tristate "ST M41T00 RTC chip (DEPRECATED)"
>  	depends on PPC32
>  	help
>  	  If you say yes here you get support for the ST M41T00 RTC chip.
> @@ -109,6 +114,9 @@ config SENSORS_M41T00
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called m41t00.
>  
> +	  This driver is deprecated and will be dropped soon. Use
> +	  rtc-ds1307 instead.
> +
>  config SENSORS_MAX6875
>  	tristate "Maxim MAX6875 Power supply supervisor"
>  	depends on EXPERIMENTAL
> --- linux-2.6.21-git.orig/Documentation/feature-removal-schedule.txt	2007-05-11 09:08:14.000000000 +0200
> +++ linux-2.6.21-git/Documentation/feature-removal-schedule.txt	2007-05-11 09:17:34.000000000 +0200
> @@ -343,3 +343,10 @@ Why:	Broken. It depends on i2c-algo-8xx 
>  Who:	Jean Delvare <khali at linux-fr.org>
>  
>  ---------------------------
> +
> +What:	legacy RTC drivers (under drivers/i2c/chips)
> +When:	November 2007
> +Why:	Obsolete. We have a RTC subsystem with better drivers.
> +Who:	Jean Delvare <khali at linux-fr.org>
> +
> +---------------------------
> 
>