Liam Girdwood | e7d0fe3 | 2008-04-30 17:22:50 +0100 | [diff] [blame^] | 1 | Regulator Machine Driver Interface |
| 2 | =================================== |
| 3 | |
| 4 | The regulator machine driver interface is intended for board/machine specific |
| 5 | initialisation code to configure the regulator subsystem. Typical things that |
| 6 | machine drivers would do are :- |
| 7 | |
| 8 | 1. Regulator -> Device mapping. |
| 9 | 2. Regulator supply configuration. |
| 10 | 3. Power Domain constraint setting. |
| 11 | |
| 12 | |
| 13 | |
| 14 | 1. Regulator -> device mapping |
| 15 | ============================== |
| 16 | Consider the following machine :- |
| 17 | |
| 18 | Regulator-1 -+-> Regulator-2 --> [Consumer A @ 1.8 - 2.0V] |
| 19 | | |
| 20 | +-> [Consumer B @ 3.3V] |
| 21 | |
| 22 | The drivers for consumers A & B must be mapped to the correct regulator in |
| 23 | order to control their power supply. This mapping can be achieved in machine |
| 24 | initialisation code by calling :- |
| 25 | |
| 26 | int regulator_set_device_supply(const char *regulator, struct device *dev, |
| 27 | const char *supply); |
| 28 | |
| 29 | and is shown with the following code :- |
| 30 | |
| 31 | regulator_set_device_supply("Regulator-1", devB, "Vcc"); |
| 32 | regulator_set_device_supply("Regulator-2", devA, "Vcc"); |
| 33 | |
| 34 | This maps Regulator-1 to the 'Vcc' supply for Consumer B and maps Regulator-2 |
| 35 | to the 'Vcc' supply for Consumer A. |
| 36 | |
| 37 | |
| 38 | 2. Regulator supply configuration. |
| 39 | ================================== |
| 40 | Consider the following machine (again) :- |
| 41 | |
| 42 | Regulator-1 -+-> Regulator-2 --> [Consumer A @ 1.8 - 2.0V] |
| 43 | | |
| 44 | +-> [Consumer B @ 3.3V] |
| 45 | |
| 46 | Regulator-1 supplies power to Regulator-2. This relationship must be registered |
| 47 | with the core so that Regulator-1 is also enabled when Consumer A enables it's |
| 48 | supply (Regulator-2). |
| 49 | |
| 50 | This relationship can be register with the core via :- |
| 51 | |
| 52 | int regulator_set_supply(const char *regulator, const char *regulator_supply); |
| 53 | |
| 54 | In this example we would use the following code :- |
| 55 | |
| 56 | regulator_set_supply("Regulator-2", "Regulator-1"); |
| 57 | |
| 58 | Relationships can be queried by calling :- |
| 59 | |
| 60 | const char *regulator_get_supply(const char *regulator); |
| 61 | |
| 62 | |
| 63 | 3. Power Domain constraint setting. |
| 64 | =================================== |
| 65 | Each power domain within a system has physical constraints on voltage and |
| 66 | current. This must be defined in software so that the power domain is always |
| 67 | operated within specifications. |
| 68 | |
| 69 | Consider the following machine (again) :- |
| 70 | |
| 71 | Regulator-1 -+-> Regulator-2 --> [Consumer A @ 1.8 - 2.0V] |
| 72 | | |
| 73 | +-> [Consumer B @ 3.3V] |
| 74 | |
| 75 | This gives us two regulators and two power domains: |
| 76 | |
| 77 | Domain 1: Regulator-2, Consumer B. |
| 78 | Domain 2: Consumer A. |
| 79 | |
| 80 | Constraints can be registered by calling :- |
| 81 | |
| 82 | int regulator_set_platform_constraints(const char *regulator, |
| 83 | struct regulation_constraints *constraints); |
| 84 | |
| 85 | The example is defined as follows :- |
| 86 | |
| 87 | struct regulation_constraints domain_1 = { |
| 88 | .min_uV = 3300000, |
| 89 | .max_uV = 3300000, |
| 90 | .valid_modes_mask = REGULATOR_MODE_NORMAL, |
| 91 | }; |
| 92 | |
| 93 | struct regulation_constraints domain_2 = { |
| 94 | .min_uV = 1800000, |
| 95 | .max_uV = 2000000, |
| 96 | .valid_ops_mask = REGULATOR_CHANGE_VOLTAGE, |
| 97 | .valid_modes_mask = REGULATOR_MODE_NORMAL, |
| 98 | }; |
| 99 | |
| 100 | regulator_set_platform_constraints("Regulator-1", &domain_1); |
| 101 | regulator_set_platform_constraints("Regulator-2", &domain_2); |