Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / Documentation / power / regulator / machine.txt

diff --git a/kernel/Documentation/power/regulator/machine.txt b/kernel/Documentation/power/regulator/machine.txt
new file mode 100644 (file)
index 0000000..757e3b5
--- /dev/null
+++ b/kernel/Documentation/power/regulator/machine.txt
@@ -0,0 +1,100 @@
+Regulator Machine Driver Interface
+===================================
+
+The regulator machine driver interface is intended for board/machine specific
+initialisation code to configure the regulator subsystem.
+
+Consider the following machine :-
+
+  Regulator-1 -+-> Regulator-2 --> [Consumer A @ 1.8 - 2.0V]
+               |
+               +-> [Consumer B @ 3.3V]
+
+The drivers for consumers A & B must be mapped to the correct regulator in
+order to control their power supplies. This mapping can be achieved in machine
+initialisation code by creating a struct regulator_consumer_supply for
+each regulator.
+
+struct regulator_consumer_supply {
+       const char *dev_name;   /* consumer dev_name() */
+       const char *supply;     /* consumer supply - e.g. "vcc" */
+};
+
+e.g. for the machine above
+
+static struct regulator_consumer_supply regulator1_consumers[] = {
+{
+       .dev_name       = "dev_name(consumer B)",
+       .supply         = "Vcc",
+},};
+
+static struct regulator_consumer_supply regulator2_consumers[] = {
+{
+       .dev    = "dev_name(consumer A"),
+       .supply = "Vcc",
+},};
+
+This maps Regulator-1 to the 'Vcc' supply for Consumer B and maps Regulator-2
+to the 'Vcc' supply for Consumer A.
+
+Constraints can now be registered by defining a struct regulator_init_data
+for each regulator power domain. This structure also maps the consumers
+to their supply regulators :-
+
+static struct regulator_init_data regulator1_data = {
+       .constraints = {
+               .name = "Regulator-1",
+               .min_uV = 3300000,
+               .max_uV = 3300000,
+               .valid_modes_mask = REGULATOR_MODE_NORMAL,
+       },
+       .num_consumer_supplies = ARRAY_SIZE(regulator1_consumers),
+       .consumer_supplies = regulator1_consumers,
+};
+
+The name field should be set to something that is usefully descriptive
+for the board for configuration of supplies for other regulators and
+for use in logging and other diagnostic output.  Normally the name
+used for the supply rail in the schematic is a good choice.  If no
+name is provided then the subsystem will choose one.
+
+Regulator-1 supplies power to Regulator-2. This relationship must be registered
+with the core so that Regulator-1 is also enabled when Consumer A enables its
+supply (Regulator-2). The supply regulator is set by the supply_regulator
+field below and co:-
+
+static struct regulator_init_data regulator2_data = {
+       .supply_regulator = "Regulator-1",
+       .constraints = {
+               .min_uV = 1800000,
+               .max_uV = 2000000,
+               .valid_ops_mask = REGULATOR_CHANGE_VOLTAGE,
+               .valid_modes_mask = REGULATOR_MODE_NORMAL,
+       },
+       .num_consumer_supplies = ARRAY_SIZE(regulator2_consumers),
+       .consumer_supplies = regulator2_consumers,
+};
+
+Finally the regulator devices must be registered in the usual manner.
+
+static struct platform_device regulator_devices[] = {
+{
+       .name = "regulator",
+       .id = DCDC_1,
+       .dev = {
+               .platform_data = &regulator1_data,
+       },
+},
+{
+       .name = "regulator",
+       .id = DCDC_2,
+       .dev = {
+               .platform_data = &regulator2_data,
+       },
+},
+};
+/* register regulator 1 device */
+platform_device_register(&regulator_devices[0]);
+
+/* register regulator 2 device */
+platform_device_register(&regulator_devices[1]);