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>

2 files changed, 80 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/pmic/sandbox.txt b/doc/device-tree-bindings/pmic/sandbox.txt
new file mode 100644
index 0000000..d84c977
--- /dev/null
+++ b/doc/device-tree-bindings/pmic/sandbox.txt
@@ -0,0 +1,35 @@
+Sandbox pmic
+
+This device uses two drivers:
+- drivers/power/pmic/sandbox.c (for parent device)
+- drivers/power/regulator/sandbox.c (for child regulators)
+
+This file describes the binding info for the PMIC driver.
+
+To bind the regulators, please read the regulator binding info:
+- doc/device-tree-bindings/regulator/sandbox.txt
+
+Required PMIC node properties:
+- compatible: "sandbox,pmic"
+- reg = 0x40
+
+Required PMIC's "emul" subnode,  with property:
+- compatible: "sandbox,i2c-pmic"
+
+With the above properties, the pmic device can be used for read/write only.
+To bind each regulator, the optional regulator subnodes should exists.
+
+Optional subnodes:
+- ldo/buck subnodes of each device's regulator (see regulator binding info)
+
+Example:
+
+sandbox_pmic {
+	compatible = "sandbox,pmic";
+	reg = <0x40>;
+
+	/* Mandatory for I/O */
+	emul {
+		compatible = "sandbox,i2c-pmic";
+	};
+};
diff --git a/doc/device-tree-bindings/regulator/sandbox.txt b/doc/device-tree-bindings/regulator/sandbox.txt
new file mode 100644
index 0000000..d70494c
--- /dev/null
+++ b/doc/device-tree-bindings/regulator/sandbox.txt
@@ -0,0 +1,45 @@
+Sandbox, PMIC regulators
+
+This device uses two drivers:
+- drivers/power/pmic/sandbox.c (as parent I/O device)
+- drivers/power/regulator/sandbox.c (for child regulators)
+
+This file describes the binding info for the REGULATOR driver.
+
+First, please read the binding info for the PMIC:
+- doc/device-tree-bindings/pmic/sandbox.txt
+
+Required subnodes:
+- ldoN { };
+- buckN { };
+
+The sandbox PMIC can support: ldo1, ldo2, buck1, buck2.
+
+For each PMIC's regulator subnode, there is one required property:
+- regulator-name: used for regulator uclass platform data '.name'
+
+Optional:
+- regulator-min-microvolt: minimum allowed Voltage to set
+- regulator-max-microvolt: minimum allowed Voltage to set
+- regulator-min-microamps: minimum allowed Current limit to set (LDO1/BUCK1)
+- regulator-max-microamps: minimum allowed Current limit to set (LDO1/BUCK1)
+- regulator-always-on: regulator should be never disabled
+- regulator-boot-on: regulator should be enabled by the bootloader
+
+Example PMIC's regulator subnodes:
+
+ldo1 {
+	regulator-name = "VDD_1.0V";
+	regulator-min-microvolt = <1000000>;
+	regulator-max-microvolt = <1200000>;
+	regulator-min-microamps = <100000>;
+	regulator-max-microamps = <400000>;
+	regulator-always-on;
+};
+
+buck2 {
+	regulator-name = "VDD_1.8V";
+	regulator-min-microvolt = <1800000>;
+	regulator-max-microvolt = <1800000>;
+	regulator-boot-on;
+};