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