regulator: anatop: Add support for "anatop-enable-bit"

Add code to support support for "anatop-enable-bit" device-tree
property. This property translates to LINREG_ENABLE bit in real hardware
and is present on 1p1, 2p5 and 3p0 regulators on i.MX6 and 1p0d regulator
on i.MX7.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/anatop-regulator.txt

@@ -14,6 +14,7 @@ Optional properties:
 - anatop-delay-bit-shift: Bit shift for the step time register
 - anatop-delay-bit-width: Number of bits used in the step time register
 - vin-supply: The supply for this regulator
+- anatop-enable-bit: Regulator enable bit offset
 
 Any property defined as part of the core regulator
 binding, defined in regulator.txt, can also be used.

drivers/regulator/anatop-regulator.c

@@ -301,7 +301,19 @@ static int anatop_regulator_probe(struct platform_device *pdev)
 			return -EINVAL;
 		}
 	} else {
+		u32 enable_bit;
+
 		rdesc->ops = &anatop_rops;
+
+		if (!of_property_read_u32(np, "anatop-enable-bit",
+					  &enable_bit)) {
+			anatop_rops.enable  = regulator_enable_regmap;
+			anatop_rops.disable = regulator_disable_regmap;
+			anatop_rops.is_enabled = regulator_is_enabled_regmap;
+
+			rdesc->enable_reg = sreg->control_reg;
+			rdesc->enable_mask = BIT(enable_bit);
+		}
 	}
 
 	/* register regulator */