kernel: ltc3882: add ltc3882 dc-dc to cex7 device tree

this patch adds ltc3882 to the device tree and exposes it via 'sensors'
-

as an example -
root@localhost:~# sensors
ltc3882-i2c-5-5c
Adapter: i2c-0-mux (chan_id 2)
vin:         +12.00 V  (min =  +6.30 V, crit max = +15.50 V)
                       (highest = +12.16 V)
vout1:        +0.78 V  (crit min =  +0.72 V, min =  +0.73 V)
                       (max =  +0.84 V, crit max =  +0.86 V)
                       (highest =  +0.78 V)
vout2:        +0.78 V  (crit min =  +0.72 V, min =  +0.73 V)
                       (max =  +0.84 V, crit max =  +0.86 V)
                       (highest =  +0.78 V)
temp1:        +49.6°C  (high = +85.0°C, crit low = -40.0°C)
                       (crit = +90.0°C, highest = +55.8°C)
temp2:        +48.8°C  (high = +85.0°C, crit low = -40.0°C)
                       (crit = +90.0°C, highest = +55.3°C)
temp3:        +53.0°C  (high = +85.0°C, crit low = -40.0°C)
                       (crit = +90.0°C, highest = +57.4°C)
pout1:         6.13 W
pout2:         5.87 W
iout1:        +7.79 A  (max = +50.00 A, crit max = +50.00 A)
                       (highest = +16.44 A)
iout2:        +7.57 A  (max = +50.00 A, crit max = +50.00 A)
                       (highest = +16.78 A)
Signed-off-by: Rabeeh Khoury <rabeeh@solid-run.com>

configs/linux/lx2k_additions.config

@@ -20,3 +20,7 @@ CONFIG_DRM_AMDGPU_CIK=y
 CONFIG_DRM_AMDGPU_USERPTR=y
 CONFIG_DRM_AMD_DC=y
 CONFIG_CHASH=m
+CONFIG_PMBUS=y
+CONFIG_SENSORS_PMBUS=y
+CONFIG_SENSORS_LTC2978=y
+CONFIG_SENSORS_LTC2978_REGULATOR=y

patches/linux/0005-arm64-dts-lx2160a-cex7-add-ltc3882-support.patch

+From cca2439ac83136b9ed85f8519931018d4f5385e6 Mon Sep 17 00:00:00 2001
+From: Rabeeh Khoury <rabeeh@solid-run.com>
+Date: Sun, 12 Jan 2020 14:24:47 +0200
+Subject: [PATCH] arm64: dts: lx2160a-cex7: add ltc3882 support
+
+ltc3882 is lx2 cortex-a72 core voltage.
+this patch adds it to the device tree support; the driver is in
+drivers/hwmon/pmbus/ltc2978.c
+
+Signed-off-by: Rabeeh Khoury <rabeeh@solid-run.com>
+---
+ arch/arm64/boot/dts/freescale/fsl-lx2160a-cex7.dts | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+diff --git a/arch/arm64/boot/dts/freescale/fsl-lx2160a-cex7.dts b/arch/arm64/boot/dts/freescale/fsl-lx2160a-cex7.dts
+index 872fcf9e724d..1c1a0d47897d 100644
+--- a/arch/arm64/boot/dts/freescale/fsl-lx2160a-cex7.dts
++++ b/arch/arm64/boot/dts/freescale/fsl-lx2160a-cex7.dts
+@@ -94,6 +94,15 @@ I2C switch -
+ 				#cooling-cells = <2>;
+ 			};
+ 		};
++		i2c@2 {
++			#address-cells = <1>;
++			#size-cells = <0>;
++			reg = <0x2>;
++			ltc3882@5c {
++				compatible = "ltc3882";
++				reg = <0x5c>;
++			};
++		};
+ 		i2c@3 {
+ 			#address-cells = <1>;
+ 			#size-cells = <0>;
+-- 
+2.17.1
+