[PATCH 7/7] media: uvcvideo: Introduce UVC_QUIRK_PRIVACY_DURING_STREAM

[Ricardo Ribalda <ribalda@xxxxxxxxxxxx>]

Some devices power the GPIO pull-up with the same power-supply as the
camera. Avoid reading the GPIO if the device is not streaming.

Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
 drivers/media/usb/uvc/uvc_gpio.c  | 47 +++++++++++++++++++++++++++++++++++++++
 drivers/media/usb/uvc/uvc_video.c |  4 ++++
 drivers/media/usb/uvc/uvcvideo.h  |  7 ++++--
 3 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_gpio.c b/drivers/media/usb/uvc/uvc_gpio.c
index e02d46ef9566..b49a7fbd5adf 100644
--- a/drivers/media/usb/uvc/uvc_gpio.c
+++ b/drivers/media/usb/uvc/uvc_gpio.c
@@ -5,6 +5,7 @@
  *      Copyright 2024 Google LLC
  */
 
+#include <linux/dmi.h>
 #include <linux/kernel.h>
 #include <linux/gpio/consumer.h>
 #include <media/v4l2-ctrls.h>
@@ -16,6 +17,9 @@ static int uvc_gpio_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
 	struct uvc_gpio *gpio =
 		container_of(ctrl->handler, struct uvc_gpio, hdl);
 
+	if (!gpio->gpio_ready)
+		return -EBUSY;
+
 	ret = gpiod_get_value_cansleep(gpio->gpio_privacy);
 	if (ret < 0)
 		return ret;
@@ -43,6 +47,24 @@ static irqreturn_t uvc_gpio_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static const struct dmi_system_id privacy_valid_during_streamon[] = {
+	{
+		.ident = "HP Elite c1030 Chromebook",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Jinlon"),
+		},
+	},
+	{
+		.ident = "HP Pro c640 Chromebook",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Dratini"),
+		},
+	},
+	{ } /* terminate list */
+};
+
 int uvc_gpio_parse(struct uvc_device *dev)
 {
 	struct gpio_desc *gpio_privacy;
@@ -64,6 +86,15 @@ int uvc_gpio_parse(struct uvc_device *dev)
 	if (IS_ERR(unit))
 		return PTR_ERR(unit);
 
+	/*
+	 * Note: This quirk will not match external UVC cameras,
+	 * as they will not have the corresponding ACPI GPIO entity.
+	 */
+	if (dmi_check_system(privacy_valid_during_streamon))
+		dev->quirks |= UVC_QUIRK_PRIVACY_DURING_STREAM;
+	else
+		unit->gpio.gpio_ready = true;
+
 	unit->gpio.gpio_privacy = gpio_privacy;
 	unit->gpio.irq = irq;
 	strscpy(unit->name, "GPIO", sizeof(unit->name));
@@ -74,6 +105,20 @@ int uvc_gpio_parse(struct uvc_device *dev)
 	return 0;
 }
 
+void uvc_gpio_quirk(struct uvc_device *dev, bool stream_on)
+{
+	if (!dev->gpio_unit || !(dev->quirks & UVC_QUIRK_PRIVACY_DURING_STREAM))
+		return;
+
+	dev->gpio_unit->gpio.gpio_ready = stream_on;
+	if (stream_on) {
+		enable_irq(dev->gpio_unit->gpio.irq);
+		uvc_gpio_irq(0, &dev->gpio_unit->gpio);
+	} else {
+		disable_irq(dev->gpio_unit->gpio.irq);
+	}
+}
+
 int uvc_gpio_init(struct uvc_device *dev)
 {
 	struct uvc_entity *unit = dev->gpio_unit;
@@ -97,6 +142,8 @@ int uvc_gpio_init(struct uvc_device *dev)
 		goto cleanup;
 	}
 
+	uvc_gpio_quirk(dev, false);
+
 	unit->gpio.privacy_ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE |
 					  V4L2_CTRL_FLAG_READ_ONLY;
 
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index cd9c29532fb0..0d542176ccde 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -2296,6 +2296,8 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
 	if (ret < 0)
 		goto error_video;
 
+	uvc_gpio_quirk(stream->dev, true);
+
 	return 0;
 
 error_video:
@@ -2308,6 +2310,8 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
 
 void uvc_video_stop_streaming(struct uvc_streaming *stream)
 {
+	uvc_gpio_quirk(stream->dev, false);
+
 	uvc_video_stop_transfer(stream, 1);
 
 	if (stream->intf->num_altsetting > 1) {
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 37991d35088c..f154cb2932a0 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -77,6 +77,7 @@
 #define UVC_QUIRK_NO_RESET_RESUME	0x00004000
 #define UVC_QUIRK_DISABLE_AUTOSUSPEND	0x00008000
 #define UVC_QUIRK_INVALID_DEVICE_SOF	0x00010000
+#define UVC_QUIRK_PRIVACY_DURING_STREAM	0x00020000
 
 /* Format flags */
 #define UVC_FMT_FLAG_COMPRESSED		0x00000001
@@ -173,10 +174,11 @@ struct uvc_control {
 #define UVC_ENTITY_FLAG_DEFAULT		(1 << 0)
 
 struct uvc_gpio {
-	struct gpio_desc *gpio_privacy;
+	bool gpio_ready;
 	int irq;
-	struct v4l2_ctrl_handler hdl;
 	struct v4l2_ctrl *privacy_ctrl;
+	struct v4l2_ctrl_handler hdl;
+	struct gpio_desc *gpio_privacy;
 };
 
 struct uvc_entity {
@@ -821,5 +823,6 @@ size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
 int uvc_gpio_init(struct uvc_device *dev);
 int uvc_gpio_parse(struct uvc_device *dev);
 void uvc_gpio_cleanup(struct uvc_entity *entity);
+void uvc_gpio_quirk(struct uvc_device *dev, bool stream_on);
 
 #endif

-- 
2.47.0.163.g1226f6d8fa-goog