x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 69 insertions, 0 deletions

diff --git a/drivers/regulator/mpq7920.h b/drivers/regulator/mpq7920.h
new file mode 100644
index 000000000..489924655
--- /dev/null
+++ b/drivers/regulator/mpq7920.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * mpq7920.h  -  Regulator definitions for mpq7920
+ *
+ * Copyright 2019 Monolithic Power Systems, Inc
+ *
+ */
+
+#ifndef __MPQ7920_H__
+#define __MPQ7920_H__
+
+#define MPQ7920_REG_CTL0		0x00
+#define MPQ7920_REG_CTL1		0x01
+#define MPQ7920_REG_CTL2		0x02
+#define MPQ7920_BUCK1_REG_A		0x03
+#define MPQ7920_BUCK1_REG_B		0x04
+#define MPQ7920_BUCK1_REG_C		0x05
+#define MPQ7920_BUCK1_REG_D		0x06
+#define MPQ7920_BUCK2_REG_A		0x07
+#define MPQ7920_BUCK2_REG_B		0x08
+#define MPQ7920_BUCK2_REG_C		0x09
+#define MPQ7920_BUCK2_REG_D		0x0a
+#define MPQ7920_BUCK3_REG_A		0x0b
+#define MPQ7920_BUCK3_REG_B		0x0c
+#define MPQ7920_BUCK3_REG_C		0x0d
+#define MPQ7920_BUCK3_REG_D		0x0e
+#define MPQ7920_BUCK4_REG_A		0x0f
+#define MPQ7920_BUCK4_REG_B		0x10
+#define MPQ7920_BUCK4_REG_C		0x11
+#define MPQ7920_BUCK4_REG_D		0x12
+#define MPQ7920_LDO1_REG_A		0x13
+#define MPQ7920_LDO1_REG_B		0x0
+#define MPQ7920_LDO2_REG_A		0x14
+#define MPQ7920_LDO2_REG_B		0x15
+#define MPQ7920_LDO2_REG_C		0x16
+#define MPQ7920_LDO3_REG_A		0x17
+#define MPQ7920_LDO3_REG_B		0x18
+#define MPQ7920_LDO3_REG_C		0x19
+#define MPQ7920_LDO4_REG_A		0x1a
+#define MPQ7920_LDO4_REG_B		0x1b
+#define MPQ7920_LDO4_REG_C		0x1c
+#define MPQ7920_LDO5_REG_A		0x1d
+#define MPQ7920_LDO5_REG_B		0x1e
+#define MPQ7920_LDO5_REG_C		0x1f
+#define MPQ7920_REG_MODE		0x20
+#define MPQ7920_REG_REGULATOR_EN	0x22
+
+#define MPQ7920_MASK_VREF		0x7f
+#define MPQ7920_MASK_BUCK_ILIM		0xc0
+#define MPQ7920_MASK_LDO_ILIM		BIT(6)
+#define MPQ7920_MASK_DISCHARGE		BIT(5)
+#define MPQ7920_MASK_MODE		0xc0
+#define MPQ7920_MASK_SOFTSTART		0x0c
+#define MPQ7920_MASK_SWITCH_FREQ	0x30
+#define MPQ7920_MASK_BUCK_PHASE_DEALY	0x30
+#define MPQ7920_MASK_DVS_SLEWRATE	0xc0
+#define MPQ7920_MASK_OVP		0x40
+#define MPQ7920_OVP_DISABLE		~(0x40)
+#define MPQ7920_DISCHARGE_ON		BIT(5)
+
+#define MPQ7920_REGULATOR_EN_OFFSET	7
+
+/* values in mV */
+#define MPQ7920_BUCK_VOLT_MIN		400000
+#define MPQ7920_LDO_VOLT_MIN		650000
+#define MPQ7920_VOLT_MAX		3587500
+#define MPQ7920_VOLT_STEP		12500
+
+#endif /* __MPQ7920_H__ */