doc/driver-model/pmic-framework.txt

2 # (C) Copyright 2014-2015 Samsung Electronics
5 # SPDX-License-Identifier:      GPL-2.0+
14 4. Regulator uclass
18 This is an introduction to driver-model multi uclass PMIC IC's support.
20 - UCLASS_PMIC      - basic uclass type for PMIC I/O, which provides common
22 - UCLASS_REGULATOR - additional uclass type for specific PMIC features,
23                      which are Voltage/Current regulators.
27 - drivers/power/pmic/pmic-uclass.c
28 - include/power/pmic.h
30 - drivers/power/regulator/regulator-uclass.c
31 - include/power/regulator.h
34 - common/cmd_pmic.c
35 - common/cmd_regulator.c
40 to provide stable, precise and specific voltage power source with over-voltage
41 and thermal protection circuits.
46 -- SoC
49  | BUS 0     |       Multi interface PMIC IC        |--> LDO out 1
50  | e.g.I2C0  |                                      |--> LDO out N
51  |-----------|---- PMIC device 0 (READ/WRITE ops)   |
52  | or SPI0   |    |_ REGULATOR device (ldo/... ops) |--> BUCK out 1
53  |           |    |_ CHARGER device (charger ops)   |--> BUCK out M
55  | BUS 1     |    |_ ...                            |---> BATTERY
57  |-----------|---- PMIC device 1 (READ/WRITE ops)   |---> USB in 1
58  . or SPI1   |    |_ RTC device (rtc ops)           |---> USB in 2
59  .           |______________________________________|---> USB out
62 Since U-Boot provides driver model features for I2C and SPI bus drivers,
63 the PMIC devices should also support this. By the pmic and regulator API's,
64 PMIC drivers can simply provide a common functions, for multi-interface and
65 and multi-instance device support.
69 - Common I/O API - UCLASS_PMIC
70 For the multi-function PMIC devices, this can be used as parent I/O device
73 - Common regulator API - UCLASS_REGULATOR
74 For driving the regulator attributes, auto setting function or command line
75 interface, based on kernel-style regulator device tree constraints.
77 For simple implementations, regulator drivers are not required, so the code can
85 * Core:     'drivers/power/pmic/pmic-uclass.c'
97 of regulator's node, compatible prefixes.
102 - list pmic devices
103 - choose the current device (like the mmc command)
104 - read or write the pmic register
105 - dump all pmic registers
112 4. Regulator uclass
116 * Header:  'include/power/regulator.h'
117 * Core:    'drivers/power/regulator/regulator-uclass.c'
119   binding: 'doc/device-tree-bindings/regulator/regulator.txt'
122 * Example: 'drivers/power/regulator/max77686.c'
124 * Example: 'drivers/power/regulator/fixed.c'
129 For the example regulator driver, please refer to the MAX77686 regulator driver,
131 I/O interface for MAX77686 regulator.
133 The second example is a fixed Voltage/Current regulator for a common use.
135 The 'regulator' command also supports the new API. The command allow:
136 - list regulator devices
137 - choose the current device (like the mmc command)
138 - do all regulator-specific operations