thermal: imx_tmu: extend with QorIQ/Layerscape TMU

Add support for the on-die Thermal Monitoring Unit (TMU) of the
new QorIQ/Layerscape SoCs (LX2160A, LS1028A, LS1088A, ...):

examples on a lx2160:
  => temperature list
  | Device                  | Driver  | Parent
  | tmu@1f80000             | imx_tmu | root_driver
  | cluster67-thermal       | imx_tmu | tmu@1f80000
  | ddr1-cluster5-thermal   | imx_tmu | tmu@1f80000
  | wriop-thermal           | imx_tmu | tmu@1f80000
  | dce-qbman-hsio2-thermal | imx_tmu | tmu@1f80000
  | ccn-dpaa-tbu-thermal    | imx_tmu | tmu@1f80000
  | cluster4-hsio3-thermal  | imx_tmu | tmu@1f80000
  | cluster23-thermal       | imx_tmu | tmu@1f80000

  => temperature get tmu@1f80000
  tmu@1f80000: 82000 mC

  => temperature get wriop-thermal
  wriop-thermal: 81000 mC

The parent tmu@... node owns the MMIO and calibration; one
UCLASS_THERMAL device is bound per/thermal-zones site so each shows
up by its zone name:

  => dm tree
   ...
   thermal   2  [ + ]   imx_tmu   |-- tmu@1f80000
   thermal   3  [ + ]   imx_tmu   |   |-- cluster67-thermal
   thermal   4  [ + ]   imx_tmu   |   |-- ddr1-cluster5-thermal
   thermal   5  [ + ]   imx_tmu   |   |-- wriop-thermal
   thermal   6  [ + ]   imx_tmu   |   |-- dce-qbman-hsio2-thermal
   thermal   7  [ + ]   imx_tmu   |   |-- ccn-dpaa-tbu-thermal
   thermal   8  [ + ]   imx_tmu   |   |-- cluster4-hsio3-thermal
   thermal   9  [ + ]   imx_tmu   |   `-- cluster23-thermal
   ...

The dtsi additions mirror the existing fsl-ls1028a.dtsi: the LX2160A
SoC dtsi gains the tmu@1f80000 node plus a thermal-zones hierarchy
with 7 sites:

  cluster67-thermal       site 0  A72 clusters 6 + 7
  ddr1-cluster5-thermal   site 1  DDR1 + A72 cluster 5
  wriop-thermal           site 2  WRIOP
  dce-qbman-hsio2-thermal site 3  DCE + QBMAN + HSIO2
  ccn-dpaa-tbu-thermal    site 4  CCN508 + DPAA + TBU
  cluster4-hsio3-thermal  site 5  A72 cluster 4 + HSIO3
  cluster23-thermal       site 6  A72 clusters 2 + 3

Signed-off-by: Vincent Jardin <[email protected]>
Suggested-by: Tom Rini <[email protected]>
Inspired-by: Peng Fan <[email protected]>
Signed-off-by: Peng Fan <[email protected]>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/arm/include/asm/arch-fsl-layerscape/sys_proto.h b/arch/arm/include/asm/arch-fsl-layerscape/sys_proto.h
new file mode 100644
index 00000000000..3b78e73c726
--- /dev/null
+++ b/arch/arm/include/asm/arch-fsl-layerscape/sys_proto.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2026 Free Mobile - Vincent Jardin
+ *
+ * Layerscape mirror of the i.MX <asm/mach-imx/sys_proto.h>: declares
+ * the SoC-personality helpers consumed by generic drivers that work on
+ * both i.MX and QorIQ/Layerscape parts (e.g. drivers/thermal/imx_tmu.c
+ * for the QorIQ TMU variant).
+ */
+
+#ifndef _ASM_ARCH_FSL_LAYERSCAPE_SYS_PROTO_H
+#define _ASM_ARCH_FSL_LAYERSCAPE_SYS_PROTO_H
+
+#include <linux/types.h>
+
+/*
+ * Per LX2160A Reference Manual, Rev. 1 (10/2021):
+ *  - section 1.12.1: "NXP specs max power at 105 degC junction" for
+ *    commercial / embedded operating conditions.
+ *  - section 28.1:   TMU "Accuracy within +/- 3 degC".
+ *
+ * Layerscape SoCs do not expose an OCOTP-style "CPU temp grade" fuse,
+ * so the implementation returns the documented junction-temperature
+ * limit from the data sheet (-40 .. 105 degC commercial range). The
+ * thermal driver subtracts 10 degC for its alert threshold, which
+ * comfortably clears the +/- 3 degC TMU accuracy in both directions.
+ */
+u32 get_cpu_temp_grade(int *minc, int *maxc);
+
+#endif /* _ASM_ARCH_FSL_LAYERSCAPE_SYS_PROTO_H */