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, 226 insertions, 0 deletions

diff --git a/drivers/leds/leds-cpcap.c b/drivers/leds/leds-cpcap.c
new file mode 100644
index 000000000..87354f176
--- /dev/null
+++ b/drivers/leds/leds-cpcap.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2017 Sebastian Reichel <sre@kernel.org>
+ */
+
+#include <linux/leds.h>
+#include <linux/mfd/motorola-cpcap.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#define CPCAP_LED_NO_CURRENT 0x0001
+
+struct cpcap_led_info {
+	u16 reg;
+	u16 mask;
+	u16 limit;
+	u16 init_mask;
+	u16 init_val;
+};
+
+static const struct cpcap_led_info cpcap_led_red = {
+	.reg	= CPCAP_REG_REDC,
+	.mask	= 0x03FF,
+	.limit	= 31,
+};
+
+static const struct cpcap_led_info cpcap_led_green = {
+	.reg	= CPCAP_REG_GREENC,
+	.mask	= 0x03FF,
+	.limit	= 31,
+};
+
+static const struct cpcap_led_info cpcap_led_blue = {
+	.reg	= CPCAP_REG_BLUEC,
+	.mask	= 0x03FF,
+	.limit	= 31,
+};
+
+/* aux display light */
+static const struct cpcap_led_info cpcap_led_adl = {
+	.reg		= CPCAP_REG_ADLC,
+	.mask		= 0x000F,
+	.limit		= 1,
+	.init_mask	= 0x7FFF,
+	.init_val	= 0x5FF0,
+};
+
+/* camera privacy led */
+static const struct cpcap_led_info cpcap_led_cp = {
+	.reg		= CPCAP_REG_CLEDC,
+	.mask		= 0x0007,
+	.limit		= 1,
+	.init_mask	= 0x03FF,
+	.init_val	= 0x0008,
+};
+
+struct cpcap_led {
+	struct led_classdev led;
+	const struct cpcap_led_info *info;
+	struct device *dev;
+	struct regmap *regmap;
+	struct mutex update_lock;
+	struct regulator *vdd;
+	bool powered;
+
+	u32 current_limit;
+};
+
+static u16 cpcap_led_val(u8 current_limit, u8 duty_cycle)
+{
+	current_limit &= 0x1f; /* 5 bit */
+	duty_cycle &= 0x0f; /* 4 bit */
+
+	return current_limit << 4 | duty_cycle;
+}
+
+static int cpcap_led_set_power(struct cpcap_led *led, bool status)
+{
+	int err;
+
+	if (status == led->powered)
+		return 0;
+
+	if (status)
+		err = regulator_enable(led->vdd);
+	else
+		err = regulator_disable(led->vdd);
+
+	if (err) {
+		dev_err(led->dev, "regulator failure: %d", err);
+		return err;
+	}
+
+	led->powered = status;
+
+	return 0;
+}
+
+static int cpcap_led_set(struct led_classdev *ledc, enum led_brightness value)
+{
+	struct cpcap_led *led = container_of(ledc, struct cpcap_led, led);
+	int brightness;
+	int err;
+
+	mutex_lock(&led->update_lock);
+
+	if (value > LED_OFF) {
+		err = cpcap_led_set_power(led, true);
+		if (err)
+			goto exit;
+	}
+
+	if (value == LED_OFF) {
+		/* Avoid HW issue by turning off current before duty cycle */
+		err = regmap_update_bits(led->regmap,
+			led->info->reg, led->info->mask, CPCAP_LED_NO_CURRENT);
+		if (err) {
+			dev_err(led->dev, "regmap failed: %d", err);
+			goto exit;
+		}
+
+		brightness = cpcap_led_val(value, LED_OFF);
+	} else {
+		brightness = cpcap_led_val(value, LED_ON);
+	}
+
+	err = regmap_update_bits(led->regmap, led->info->reg, led->info->mask,
+		brightness);
+	if (err) {
+		dev_err(led->dev, "regmap failed: %d", err);
+		goto exit;
+	}
+
+	if (value == LED_OFF) {
+		err = cpcap_led_set_power(led, false);
+		if (err)
+			goto exit;
+	}
+
+exit:
+	mutex_unlock(&led->update_lock);
+	return err;
+}
+
+static const struct of_device_id cpcap_led_of_match[] = {
+	{ .compatible = "motorola,cpcap-led-red", .data = &cpcap_led_red },
+	{ .compatible = "motorola,cpcap-led-green", .data = &cpcap_led_green },
+	{ .compatible = "motorola,cpcap-led-blue",  .data = &cpcap_led_blue },
+	{ .compatible = "motorola,cpcap-led-adl", .data = &cpcap_led_adl },
+	{ .compatible = "motorola,cpcap-led-cp", .data = &cpcap_led_cp },
+	{},
+};
+MODULE_DEVICE_TABLE(of, cpcap_led_of_match);
+
+static int cpcap_led_probe(struct platform_device *pdev)
+{
+	struct cpcap_led *led;
+	int err;
+
+	led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, led);
+	led->info = device_get_match_data(&pdev->dev);
+	led->dev = &pdev->dev;
+
+	if (led->info->reg == 0x0000) {
+		dev_err(led->dev, "Unsupported LED");
+		return -ENODEV;
+	}
+
+	led->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!led->regmap)
+		return -ENODEV;
+
+	led->vdd = devm_regulator_get(&pdev->dev, "vdd");
+	if (IS_ERR(led->vdd)) {
+		err = PTR_ERR(led->vdd);
+		dev_err(led->dev, "Couldn't get regulator: %d", err);
+		return err;
+	}
+
+	err = device_property_read_string(&pdev->dev, "label", &led->led.name);
+	if (err) {
+		dev_err(led->dev, "Couldn't read LED label: %d", err);
+		return err;
+	}
+
+	if (led->info->init_mask) {
+		err = regmap_update_bits(led->regmap, led->info->reg,
+			led->info->init_mask, led->info->init_val);
+		if (err) {
+			dev_err(led->dev, "regmap failed: %d", err);
+			return err;
+		}
+	}
+
+	mutex_init(&led->update_lock);
+
+	led->led.max_brightness = led->info->limit;
+	led->led.brightness_set_blocking = cpcap_led_set;
+	err = devm_led_classdev_register(&pdev->dev, &led->led);
+	if (err) {
+		dev_err(led->dev, "Couldn't register LED: %d", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static struct platform_driver cpcap_led_driver = {
+	.probe = cpcap_led_probe,
+	.driver = {
+		.name = "cpcap-led",
+		.of_match_table = cpcap_led_of_match,
+	},
+};
+module_platform_driver(cpcap_led_driver);
+
+MODULE_DESCRIPTION("CPCAP LED driver");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_LICENSE("GPL");