There is a variation of the Kobo Clara HD containing a PMIC with different
default settings for the regulators in the OTP and therefore also
regulators wired up in a different way, so add a proper devicetree for it
to avoid some magic smoke.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
 arch/arm/boot/dts/nxp/imx/Makefile            |  1 +
 .../dts/nxp/imx/imx6sll-kobo-clarahd-b.dts    | 79 +++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 arch/arm/boot/dts/nxp/imx/imx6sll-kobo-clarahd-b.dts

diff --git a/arch/arm/boot/dts/nxp/imx/Makefile b/arch/arm/boot/dts/nxp/imx/Makefile
index 4052cad859fa9..a4826d128dfc7 100644
--- a/arch/arm/boot/dts/nxp/imx/Makefile
+++ b/arch/arm/boot/dts/nxp/imx/Makefile
@@ -288,6 +288,7 @@ dtb-$(CONFIG_SOC_IMX6SL) += \
 dtb-$(CONFIG_SOC_IMX6SLL) += \
 	imx6sll-evk.dtb \
 	imx6sll-kobo-clarahd.dtb \
+	imx6sll-kobo-clarahd-b.dtb \
 	imx6sll-kobo-librah2o.dtb
 dtb-$(CONFIG_SOC_IMX6SX) += \
 	imx6sx-nitrogen6sx.dtb \
diff --git a/arch/arm/boot/dts/nxp/imx/imx6sll-kobo-clarahd-b.dts b/arch/arm/boot/dts/nxp/imx/imx6sll-kobo-clarahd-b.dts
new file mode 100644
index 0000000000000..09b890fe915ab
--- /dev/null
+++ b/arch/arm/boot/dts/nxp/imx/imx6sll-kobo-clarahd-b.dts
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: (GPL-2.0)
+/*
+ * Device tree for the Kobo Clara HD Rev B ebook reader
+ *
+ * Name on mainboard is: 37NB-E60K00+4B0
+ * Serials start with: E60K02 (a number also seen in
+ * vendor kernel sources)
+ *
+ * Copyright 2024 Andreas Kemnade
+ */
+
+/dts-v1/;
+
+#include "imx6sll-kobo-clarahd.dts"
+
+/ {
+	model = "Kobo Clara HD Rev B";
+	compatible = "kobo,clarahd-b", "kobo,clarahd", "fsl,imx6sll";
+};
+
+&cpu0 {
+	arm-supply = <&dcdc5_reg>;
+	soc-supply = <&dcdc2_reg>;
+};
+
+&dcdc1_reg {
+	/delete-property/ regulator-min-microvolt;
+	/delete-property/ regulator-max-microvolt;
+
+	regulator-state-mem {
+		regulator-suspend-min-microvolt = <1040000>;
+		regulator-suspend-max-microvolt = <1040000>;
+	};
+};
+
+&dcdc2_reg {
+	regulator-min-microvolt = <660000>;
+	regulator-max-microvolt = <1000000>;
+
+	regulator-state-mem {
+		regulator-suspend-min-microvolt = <660000>;
+		regulator-suspend-max-microvolt = <660000>;
+	};
+};
+
+&dcdc3_reg {
+	/delete-property/ regulator-min-microvolt;
+	/delete-property/ regulator-max-microvolt;
+
+	regulator-state-mem {
+		regulator-suspend-min-microvolt = <3300000>;
+		regulator-suspend-max-microvolt = <3300000>;
+	};
+};
+
+&dcdc4_reg {
+	/delete-property/ regulator-min-microvolt;
+	/delete-property/ regulator-max-microvolt;
+
+	regulator-state-mem {
+		regulator-suspend-min-microvolt = <1700000>;
+		regulator-suspend-max-microvolt = <1700000>;
+	};
+};
+
+&dcdc5_reg {
+	regulator-min-microvolt = <710000>;
+	regulator-max-microvolt = <1100000>;
+
+	regulator-state-mem {
+		regulator-suspend-min-microvolt = <710000>;
+		regulator-suspend-max-microvolt = <710000>;
+	};
+};
+
+&ldo8_reg {
+		/delete-property/ regulator-min-microvolt;
+		/delete-property/ regulator-max-microvolt;
+};
-- 
2.39.2

On Sat,  4 May 2024 23:53:44 +0200
Andreas Kemnade <andreas@kemnade.info> wrote:

> There is a variation of the Kobo Clara HD containing a PMIC with different
> default settings for the regulators in the OTP and therefore also
> regulators wired up in a different way, so add a proper devicetree for it
> to avoid some magic smoke.
> 
[...]
> +&cpu0 {
> +	arm-supply = <&dcdc5_reg>;
> +	soc-supply = <&dcdc2_reg>;
> +};
> +
Vendor devicetree has also this snippet for that revision:

       cpus {
                cpu0: cpu@0 {
                        operating-points = <    /* Core2_1V3_ARM */
                                /* kHz    uV */
                                996000  1062500
                                792000  1062500
                                396000  1062500
                                198000  975000
                        >;
                        fsl,soc-operating-points = <    /* Core2_1V3_SOC */
                                /* ARM kHz      SOC-PU uV */
                                996000          987500
                                792000          987500
                                396000          987500
                                198000          900000
                        >;
                };

        };

Apparently we run into https://gitlab.com/postmarketOS/pmaports/-/issues/2811
but I cannot find any documentation an alternative voltage ranges for that SoC
(i.MX6SLL). So not all 6SLLs are created equal? At least we do not mix up 1.XV regulators
with 3.3 regulators now, that is more healthy.

Regards,
Andreas