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+=============================
+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.