dm: Add POWER API transition document
Signed-off-by: Viktor Krivak <viktor.krivak@gmail.com>
diff --git a/doc/driver-model/UDM-power.txt b/doc/driver-model/UDM-power.txt
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+The U-Boot Driver Model Project
+===============================
+POWER analysis
+==============
+Viktor Krivak <viktor.krivak@gmail.com>
+2012-03-09
+
+I) Overview
+-----------
+
+ 1) Actual state
+ ---------------
+
+ At this moment power doesn't contain API. There are many methods for
+ initialization of some board specific functions but only few does what is
+ expected. Basically only one file contains something meaningful for this
+ driver.
+
+ 2) Current implementation
+ -------------------------
+
+ In file twl6030.c are methods twl6030_stop_usb_charging() and
+ twl6030_start_usb_charging() for start and stop charging from USB. There are
+ also methods to get information about battery state and initialization of
+ battery charging. Only these methods are used in converted API.
+
+
+II) Approach
+------------
+
+ 1) New API
+ ----------
+
+ New API implements only functions specific for managing power. All board
+ specific init methods are moved to other files. Name of methods are
+ self-explanatory.
+
+ struct ops {
+ void (*start_usb_charging)(struct instance *i);
+ void (*stop_usb_charging)(struct instance *i);
+ int (*get_battery_current)(struct instance *i);
+ int (*get_battery_voltage)(struct instance *i);
+ void (*init_battery_charging)(struct instance *i);
+ }
+
+ 2) Conversions of other methods
+ -------------------------------
+
+ Methods that can't be converted to new API are moved to board file or to
+ special file for board hacks.
+
+III) Analysis of in-tree drivers
+--------------------------------
+
+ 1) ftpmu010.c
+ -------------
+ All methods of this file are moved to another location.
+ void ftpmu010_32768osc_enable(void): Move to boards hacks
+ void ftpmu010_mfpsr_select_dev(unsigned int dev): Move to board file
+ arch/nds32/lib/board.c
+ void ftpmu010_mfpsr_diselect_dev(unsigned int dev): Dead code
+ void ftpmu010_dlldis_disable(void): Dead code
+ void ftpmu010_sdram_clk_disable(unsigned int cr0): Move to board file
+ arch/nds32/lib/board.c
+ void ftpmu010_sdramhtc_set(unsigned int val): Move to board file
+ arch/nds32/lib/board.c
+
+ 2) twl4030.c
+ ------------
+ All methods of this file are moved to another location.
+ void twl4030_power_reset_init(void): Move to board hacks
+ void twl4030_pmrecv_vsel_cfg(u8 vsel_reg, u8 vsel_val, u8 dev_grp,
+ u8 dev_grp_sel): Move to board hacks
+ void twl4030_power_init(void): Move to board hacks
+ void twl4030_power_mmc_init(void): Move to board hacks
+
+ 3) twl6030.c
+ ------------
+ Some methods are converted to new API and rest are moved to another location.
+ void twl6030_stop_usb_charging(void): Convert to new API
+ void twl6030_start_usb_charging(void): Convert to new API
+ int twl6030_get_battery_current(void): Convert to new API
+ int twl6030_get_battery_voltage(void): Convert to new API
+ void twl6030_init_battery_charging(void): Convert to new API
+ void twl6030_power_mmc_init(): Move to board file
+ drivers/mmc/omap_hsmmc.c
+ void twl6030_usb_device_settings(): Move to board file
+ drivers/usb/musb/omap3.c