From: Tomas Hlavacek tmshlvck@gmail.com
Signed-off-by: Tomas Hlavacek tmshlvck@gmail.com --- doc/driver-model/UDM-rtc.txt | 258 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 258 insertions(+) create mode 100644 doc/driver-model/UDM-rtc.txt
diff --git a/doc/driver-model/UDM-rtc.txt b/doc/driver-model/UDM-rtc.txt new file mode 100644 index 0000000..5d9fb33 --- /dev/null +++ b/doc/driver-model/UDM-rtc.txt @@ -0,0 +1,258 @@ +============================= +RTC device subsystem analysis +============================= + +Tomas Hlavacek tmshlvck@gmail.com +2012-03-10 + +I) Overview +----------- + +U-Boot currently implements one common API for RTC devices. The interface +is defined in include/rtc.h and comprises of functions and structures: + + struct rtc_time { + int tm_sec; + int tm_min; + int tm_hour; + int tm_mday; + int tm_mon; + int tm_year; + int tm_wday; + int tm_yday; + int tm_isdst; + }; + + int rtc_get (struct rtc_time *); + int rtc_set (struct rtc_time *); + void rtc_reset (void); + +The functions are implemented by a proper device driver in drivers/rtc +directory and the driver to be compiled in is selected in a Makefile. +Drivers are mutually exclusive. + +Drivers depends on date code in drivers/rtc/date.c and naturally on board +specific data. + +II) Approach +------------ + + 1) New API + ---------- + In the UDM each rtc driver would register itself by a function + + int rtc_device_register(struct instance *i, + struct rtc_device_ops *o); + + The structure being defined as follows: + + struct rtc_device_ops { + int (*get_time)(struct instance *i, struct rtc_time *t); + int (*set_time)(struct instance *i, struct rtc_time *t); + int (*reset)(struct instance *i); + }; + + + 2) Conversion thougths + ---------------------- + U-Boot RTC drivers exports the same functions and therefore the conversion + of the drivers is straight-forward. There is no initialization needed. + + +III) Analysis of in-tree drivers +-------------------------------- + + 1) drivers/rtc/rv3029.c + ----------------------- + The driver is standard rtc. Simple conversion is possible. + + + 2) drivers/rtc/s3c24x0_rtc.c + ---------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 3) drivers/rtc/pt7c4338.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 4) drivers/rtc/mvrtc.c + ---------------------- + The driver is standard rtc. Simple conversion is possible. + + + 5) drivers/rtc/ftrtc010.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 6) drivers/rtc/mpc5xxx.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 7) drivers/rtc/ds164x.c + ----------------------- + The driver is standard rtc. Simple conversion is possible. + + + 8) drivers/rtc/rs5c372.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 9) drivers/rtc/m41t94.c + ----------------------- + The driver is standard rtc. Simple conversion is possible. + + + 10) drivers/rtc/mc13xxx-rtc.c + ----------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 11) drivers/rtc/mcfrtc.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 12) drivers/rtc/davinci.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 13) drivers/rtc/rx8025.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 14) drivers/rtc/bfin_rtc.c + -------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 15) drivers/rtc/m41t62.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 16) drivers/rtc/ds1306.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 17) drivers/rtc/mpc8xx.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 18) drivers/rtc/ds3231.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 19) drivers/rtc/ds12887.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 20) drivers/rtc/ds1302.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 21) drivers/rtc/ds1374.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 22) drivers/rtc/ds174x.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 23) drivers/rtc/m41t60.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 24) drivers/rtc/m48t35ax.c + -------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 25) drivers/rtc/pl031.c + ----------------------- + The driver is standard rtc. Simple conversion is possible. + + + 26) drivers/rtc/x1205.c + ----------------------- + The driver is standard rtc. Simple conversion is possible. + + + 27) drivers/rtc/m41t11.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 28) drivers/rtc/pcf8563.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 29) drivers/rtc/mk48t59.c + ------------------------- + Macros needs cleanup. Besides that the driver is standard rtc. + Simple conversion is possible. + + + 30) drivers/rtc/mxsrtc.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 31) drivers/rtc/ds1307.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 32) drivers/rtc/ds1556.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 33) drivers/rtc/rtc4543.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 34) drivers/rtc/s3c44b0_rtc.c + ----------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 35) drivers/rtc/ds1337.c + ------------------------ + The driver is standard rtc. Simple conversion is possible. + + + 36) drivers/rtc/isl1208.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 37) drivers/rtc/max6900.c + ------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 38) drivers/rtc/mc146818.c + -------------------------- + The driver is standard rtc. Simple conversion is possible. + + + 39) drivers/rtc/at91sam9_rtt.c + ------------------------------ + The driver is standard rtc. Simple conversion is possible.