sandbox: add: sandbox PMIC device drivers: I2C emul, pmic, regulator

This commit adds emulation of sandbox PMIC device, which includes:
- PMIC I2C emulation driver
- PMIC I/O driver (UCLASS_PMIC)
- PMIC regulator driver (UCLASS_REGULATOR)

The sandbox PMIC has 12 significant registers and 4 as padding to 16 bytes,
which allows using 'i2c md' command with the default count (16).

The sandbox PMIC provides regulators:
- 2x BUCK
- 2x LDO

Each, with adjustable output:
- Enable state
- Voltage
- Current limit (LDO1/BUCK1 only)
- Operation mode (different for BUCK and LDO)

Each attribute has it's own register, beside the enable state, which depends
on operation mode.

The header file: sandbox_pmic.h includes PMIC's default register values,
which are set on i2c pmic emul driver's probe() method.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested on sandbox:
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/include/power/sandbox_pmic.h b/include/power/sandbox_pmic.h
new file mode 100644
index 0000000..f317c3a
--- /dev/null
+++ b/include/power/sandbox_pmic.h
@@ -0,0 +1,105 @@
+/*
+ *  Copyright (C) 2015 Samsung Electronics
+ *  Przemyslaw Marczak  <p.marczak@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _SANDBOX_PMIC_H_
+#define  _SANDBOX_PMIC_H_
+
+#define SANDBOX_LDO_DRIVER		"sandbox_ldo"
+#define SANDBOX_OF_LDO_PREFIX		"ldo"
+#define SANDBOX_BUCK_DRIVER		"sandbox_buck"
+#define SANDBOX_OF_BUCK_PREFIX		"buck"
+
+#define SANDBOX_BUCK_COUNT	2
+#define SANDBOX_LDO_COUNT	2
+/*
+ * Sandbox PMIC registers:
+ * We have only 12 significant registers, but we alloc 16 for padding.
+ */
+enum {
+	SANDBOX_PMIC_REG_BUCK1_UV = 0,
+	SANDBOX_PMIC_REG_BUCK1_UA,
+	SANDBOX_PMIC_REG_BUCK1_OM,
+
+	SANDBOX_PMIC_REG_BUCK2_UV,
+	SANDBOX_PMIC_REG_BUCK2_UA,
+	SANDBOX_PMIC_REG_BUCK2_OM,
+
+	SANDBOX_PMIC_REG_LDO_OFFSET,
+	SANDBOX_PMIC_REG_LDO1_UV = SANDBOX_PMIC_REG_LDO_OFFSET,
+	SANDBOX_PMIC_REG_LDO1_UA,
+	SANDBOX_PMIC_REG_LDO1_OM,
+
+	SANDBOX_PMIC_REG_LDO2_UV,
+	SANDBOX_PMIC_REG_LDO2_UA,
+	SANDBOX_PMIC_REG_LDO2_OM,
+
+	SANDBOX_PMIC_REG_COUNT = 16,
+};
+
+/* Register offset for output: micro Volts, micro Amps, Operation Mode */
+enum {
+	OUT_REG_UV = 0,
+	OUT_REG_UA,
+	OUT_REG_OM,
+	OUT_REG_COUNT,
+};
+
+/* Buck operation modes */
+enum {
+	BUCK_OM_OFF = 0,
+	BUCK_OM_ON,
+	BUCK_OM_PWM,
+	BUCK_OM_COUNT,
+};
+
+/* Ldo operation modes */
+enum {
+	LDO_OM_OFF = 0,
+	LDO_OM_ON,
+	LDO_OM_SLEEP,
+	LDO_OM_STANDBY,
+	LDO_OM_COUNT,
+};
+
+/* BUCK1 Voltage: min: 0.8V, step: 25mV, max 2.4V */
+#define OUT_BUCK1_UV_MIN	800000
+#define OUT_BUCK1_UV_MAX	2400000
+#define OUT_BUCK1_UV_STEP	25000
+
+/* BUCK1 Amperage: min: 150mA, step: 25mA, max: 250mA */
+#define OUT_BUCK1_UA_MIN	150000
+#define OUT_BUCK1_UA_MAX	250000
+#define OUT_BUCK1_UA_STEP	25000
+
+/* BUCK2 Voltage: min: 0.75V, step: 50mV, max 3.95V */
+#define OUT_BUCK2_UV_MIN	750000
+#define OUT_BUCK2_UV_MAX	3950000
+#define OUT_BUCK2_UV_STEP	50000
+
+/* LDO1 Voltage: min: 0.8V, step: 25mV, max 2.4V */
+#define OUT_LDO1_UV_MIN		800000
+#define OUT_LDO1_UV_MAX		2400000
+#define OUT_LDO1_UV_STEP	25000
+
+/* LDO1 Amperage: min: 100mA, step: 50mA, max: 200mA */
+#define OUT_LDO1_UA_MIN		100000
+#define OUT_LDO1_UA_MAX		200000
+#define OUT_LDO1_UA_STEP	50000
+
+/* LDO2 Voltage: min: 0.75V, step: 50mV, max 3.95V */
+#define OUT_LDO2_UV_MIN		750000
+#define OUT_LDO2_UV_MAX		3950000
+#define OUT_LDO2_UV_STEP	50000
+
+/* register <-> value conversion */
+#define REG2VAL(min, step, reg)		((min) + ((step) * (reg)))
+#define VAL2REG(min, step, val)		(((val) - (min)) / (step))
+
+/* Operation mode id -> register value conversion */
+#define OM2REG(x)			(x)
+
+#endif