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Message-ID: <20241125214523.GW19381@pendragon.ideasonboard.com>
Date: Mon, 25 Nov 2024 23:45:23 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Hans de Goede <hdegoede@...hat.com>
Cc: Ricardo Ribalda <ribalda@...omium.org>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Sakari Ailus <sakari.ailus@...ux.intel.com>,
linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
Yunke Cao <yunkec@...omium.org>, Hans Verkuil <hverkuil@...all.nl>
Subject: Re: [PATCH v3 2/8] media: uvcvideo: Factor out gpio functions to its
own file
On Mon, Nov 25, 2024 at 03:45:38PM +0100, Hans de Goede wrote:
> Hi Ricardo,
>
> On 12-Nov-24 6:30 PM, Ricardo Ribalda wrote:
> > This is just a refactor patch, no new functionality is added.
> >
> > Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
>
> I guess this patch may need to change depending on if we want
> to keep the GPIO handling as a UVC entity or not.
>
> Laurent what is your take on this, should this stay as
> a struct uvc_entity; or should the gpio_desc and input_device
> be stored directly inside struct uvc_device as is done for
> the snapshot-button input_device?
If we stop exposing it as a subdev I'd rather not create a uvc_entity.
> Also de we want a separate input_device for this or do
> we re-use the snapshot button one ?
>
> Since my plan is to open-up the permission on the device with
> the SW_CAMERA_LENS_COVER to be equal to the /dev/video#
> permissions sharing has the downside of allowing keylogging
> of the snapshot button.
Given that the only standardized usage of the button is to inform
applications they should capture a still image, I don't think that's
much of a problem. Devices can also report that their button is a
generic purpose button, but I would still expect its function to be
camera-related.
Can anyone think of an attack vector ?
> Either way (one or 2 input-devices) I don't have a strong
> preference.
>
> > ---
> > drivers/media/usb/uvc/Makefile | 3 +-
> > drivers/media/usb/uvc/uvc_driver.c | 119 +------------------------------------
> > drivers/media/usb/uvc/uvc_gpio.c | 118 ++++++++++++++++++++++++++++++++++++
> > drivers/media/usb/uvc/uvcvideo.h | 8 +++
> > 4 files changed, 131 insertions(+), 117 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/Makefile b/drivers/media/usb/uvc/Makefile
> > index 4f9eee4f81ab..85514b6e538f 100644
> > --- a/drivers/media/usb/uvc/Makefile
> > +++ b/drivers/media/usb/uvc/Makefile
> > @@ -1,6 +1,7 @@
> > # SPDX-License-Identifier: GPL-2.0
> > uvcvideo-objs := uvc_driver.o uvc_queue.o uvc_v4l2.o uvc_video.o uvc_ctrl.o \
> > - uvc_status.o uvc_isight.o uvc_debugfs.o uvc_metadata.o
> > + uvc_status.o uvc_isight.o uvc_debugfs.o uvc_metadata.o \
> > + uvc_gpio.o
> > ifeq ($(CONFIG_MEDIA_CONTROLLER),y)
> > uvcvideo-objs += uvc_entity.o
> > endif
> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > index cd13bf01265d..5b48768a4f7f 100644
> > --- a/drivers/media/usb/uvc/uvc_driver.c
> > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > @@ -8,7 +8,6 @@
> >
> > #include <linux/atomic.h>
> > #include <linux/bits.h>
> > -#include <linux/gpio/consumer.h>
> > #include <linux/kernel.h>
> > #include <linux/list.h>
> > #include <linux/module.h>
> > @@ -775,9 +774,9 @@ static const u8 uvc_media_transport_input_guid[16] =
> > UVC_GUID_UVC_MEDIA_TRANSPORT_INPUT;
> > static const u8 uvc_processing_guid[16] = UVC_GUID_UVC_PROCESSING;
> >
> > -static struct uvc_entity *uvc_alloc_new_entity(struct uvc_device *dev, u16 type,
> > - u16 id, unsigned int num_pads,
> > - unsigned int extra_size)
> > +struct uvc_entity *uvc_alloc_new_entity(struct uvc_device *dev, u16 type,
> > + u16 id, unsigned int num_pads,
> > + unsigned int extra_size)
> > {
> > struct uvc_entity *entity;
> > unsigned int num_inputs;
> > @@ -1240,118 +1239,6 @@ static int uvc_parse_control(struct uvc_device *dev)
> > return 0;
> > }
> >
> > -/* -----------------------------------------------------------------------------
> > - * Privacy GPIO
> > - */
> > -
> > -static void uvc_gpio_event(struct uvc_device *dev)
> > -{
> > - struct uvc_entity *unit = dev->gpio_unit;
> > - struct uvc_video_chain *chain;
> > - u8 new_val;
> > -
> > - if (!unit)
> > - return;
> > -
> > - new_val = gpiod_get_value_cansleep(unit->gpio.gpio_privacy);
> > -
> > - /* GPIO entities are always on the first chain. */
> > - chain = list_first_entry(&dev->chains, struct uvc_video_chain, list);
> > - uvc_ctrl_status_event(chain, unit->controls, &new_val);
> > -}
> > -
> > -static int uvc_gpio_get_cur(struct uvc_device *dev, struct uvc_entity *entity,
> > - u8 cs, void *data, u16 size)
> > -{
> > - if (cs != UVC_CT_PRIVACY_CONTROL || size < 1)
> > - return -EINVAL;
> > -
> > - *(u8 *)data = gpiod_get_value_cansleep(entity->gpio.gpio_privacy);
> > -
> > - return 0;
> > -}
> > -
> > -static int uvc_gpio_get_info(struct uvc_device *dev, struct uvc_entity *entity,
> > - u8 cs, u8 *caps)
> > -{
> > - if (cs != UVC_CT_PRIVACY_CONTROL)
> > - return -EINVAL;
> > -
> > - *caps = UVC_CONTROL_CAP_GET | UVC_CONTROL_CAP_AUTOUPDATE;
> > - return 0;
> > -}
> > -
> > -static irqreturn_t uvc_gpio_irq(int irq, void *data)
> > -{
> > - struct uvc_device *dev = data;
> > -
> > - uvc_gpio_event(dev);
> > - return IRQ_HANDLED;
> > -}
> > -
> > -static int uvc_gpio_parse(struct uvc_device *dev)
> > -{
> > - struct uvc_entity *unit;
> > - struct gpio_desc *gpio_privacy;
> > - int irq;
> > -
> > - gpio_privacy = devm_gpiod_get_optional(&dev->intf->dev, "privacy",
> > - GPIOD_IN);
> > - if (IS_ERR_OR_NULL(gpio_privacy))
> > - return PTR_ERR_OR_ZERO(gpio_privacy);
> > -
> > - irq = gpiod_to_irq(gpio_privacy);
> > - if (irq < 0)
> > - return dev_err_probe(&dev->intf->dev, irq,
> > - "No IRQ for privacy GPIO\n");
> > -
> > - unit = uvc_alloc_new_entity(dev, UVC_EXT_GPIO_UNIT,
> > - UVC_EXT_GPIO_UNIT_ID, 0, 1);
> > - if (IS_ERR(unit))
> > - return PTR_ERR(unit);
> > -
> > - unit->gpio.gpio_privacy = gpio_privacy;
> > - unit->gpio.irq = irq;
> > - unit->gpio.bControlSize = 1;
> > - unit->gpio.bmControls = (u8 *)unit + sizeof(*unit);
> > - unit->gpio.bmControls[0] = 1;
> > - unit->get_cur = uvc_gpio_get_cur;
> > - unit->get_info = uvc_gpio_get_info;
> > - strscpy(unit->name, "GPIO", sizeof(unit->name));
> > -
> > - list_add_tail(&unit->list, &dev->entities);
> > -
> > - dev->gpio_unit = unit;
> > -
> > - return 0;
> > -}
> > -
> > -static int uvc_gpio_init_irq(struct uvc_device *dev)
> > -{
> > - struct uvc_entity *unit = dev->gpio_unit;
> > - int ret;
> > -
> > - if (!unit || unit->gpio.irq < 0)
> > - return 0;
> > -
> > - ret = request_threaded_irq(unit->gpio.irq, NULL, uvc_gpio_irq,
> > - IRQF_ONESHOT | IRQF_TRIGGER_FALLING |
> > - IRQF_TRIGGER_RISING,
> > - "uvc_privacy_gpio", dev);
> > -
> > - unit->gpio.initialized = !ret;
> > -
> > - return ret;
> > -}
> > -
> > -static void uvc_gpio_deinit(struct uvc_device *dev)
> > -{
> > - if (!dev->gpio_unit || !dev->gpio_unit->gpio.initialized)
> > - return;
> > -
> > - free_irq(dev->gpio_unit->gpio.irq, dev);
> > -}
> > -
> > /* ------------------------------------------------------------------------
> > * UVC device scan
> > */
> > diff --git a/drivers/media/usb/uvc/uvc_gpio.c b/drivers/media/usb/uvc/uvc_gpio.c
> > new file mode 100644
> > index 000000000000..453739acbe8f
> > --- /dev/null
> > +++ b/drivers/media/usb/uvc/uvc_gpio.c
> > @@ -0,0 +1,118 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * uvc_gpio.c -- USB Video Class driver
> > + *
> > + * Copyright 2024 Google LLC
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/gpio/consumer.h>
> > +#include "uvcvideo.h"
> > +
> > +static void uvc_gpio_event(struct uvc_device *dev)
> > +{
> > + struct uvc_entity *unit = dev->gpio_unit;
> > + struct uvc_video_chain *chain;
> > + u8 new_val;
> > +
> > + if (!unit)
> > + return;
> > +
> > + new_val = gpiod_get_value_cansleep(unit->gpio.gpio_privacy);
> > +
> > + /* GPIO entities are always on the first chain. */
> > + chain = list_first_entry(&dev->chains, struct uvc_video_chain, list);
> > + uvc_ctrl_status_event(chain, unit->controls, &new_val);
> > +}
> > +
> > +static int uvc_gpio_get_cur(struct uvc_device *dev, struct uvc_entity *entity,
> > + u8 cs, void *data, u16 size)
> > +{
> > + if (cs != UVC_CT_PRIVACY_CONTROL || size < 1)
> > + return -EINVAL;
> > +
> > + *(u8 *)data = gpiod_get_value_cansleep(entity->gpio.gpio_privacy);
> > +
> > + return 0;
> > +}
> > +
> > +static int uvc_gpio_get_info(struct uvc_device *dev, struct uvc_entity *entity,
> > + u8 cs, u8 *caps)
> > +{
> > + if (cs != UVC_CT_PRIVACY_CONTROL)
> > + return -EINVAL;
> > +
> > + *caps = UVC_CONTROL_CAP_GET | UVC_CONTROL_CAP_AUTOUPDATE;
> > + return 0;
> > +}
> > +
> > +static irqreturn_t uvc_gpio_irq(int irq, void *data)
> > +{
> > + struct uvc_device *dev = data;
> > +
> > + uvc_gpio_event(dev);
> > + return IRQ_HANDLED;
> > +}
> > +
> > +int uvc_gpio_parse(struct uvc_device *dev)
> > +{
> > + struct uvc_entity *unit;
> > + struct gpio_desc *gpio_privacy;
> > + int irq;
> > +
> > + gpio_privacy = devm_gpiod_get_optional(&dev->intf->dev, "privacy",
> > + GPIOD_IN);
> > + if (IS_ERR_OR_NULL(gpio_privacy))
> > + return PTR_ERR_OR_ZERO(gpio_privacy);
> > +
> > + irq = gpiod_to_irq(gpio_privacy);
> > + if (irq < 0)
> > + return dev_err_probe(&dev->udev->dev, irq,
> > + "No IRQ for privacy GPIO\n");
> > +
> > + unit = uvc_alloc_new_entity(dev, UVC_EXT_GPIO_UNIT,
> > + UVC_EXT_GPIO_UNIT_ID, 0, 1);
> > + if (IS_ERR(unit))
> > + return PTR_ERR(unit);
> > +
> > + unit->gpio.gpio_privacy = gpio_privacy;
> > + unit->gpio.irq = irq;
> > + unit->gpio.bControlSize = 1;
> > + unit->gpio.bmControls = (u8 *)unit + sizeof(*unit);
> > + unit->gpio.bmControls[0] = 1;
> > + unit->get_cur = uvc_gpio_get_cur;
> > + unit->get_info = uvc_gpio_get_info;
> > + strscpy(unit->name, "GPIO", sizeof(unit->name));
> > +
> > + list_add_tail(&unit->list, &dev->entities);
> > +
> > + dev->gpio_unit = unit;
> > +
> > + return 0;
> > +}
> > +
> > +int uvc_gpio_init_irq(struct uvc_device *dev)
> > +{
> > + struct uvc_entity *unit = dev->gpio_unit;
> > + int ret;
> > +
> > + if (!unit || unit->gpio.irq < 0)
> > + return 0;
> > +
> > + ret = request_threaded_irq(unit->gpio.irq, NULL, uvc_gpio_irq,
> > + IRQF_ONESHOT | IRQF_TRIGGER_FALLING |
> > + IRQF_TRIGGER_RISING,
> > + "uvc_privacy_gpio", dev);
> > +
> > + unit->gpio.initialized = !ret;
> > +
> > + return ret;
> > +}
> > +
> > +void uvc_gpio_deinit(struct uvc_device *dev)
> > +{
> > + if (!dev->gpio_unit || !dev->gpio_unit->gpio.initialized)
> > + return;
> > +
> > + free_irq(dev->gpio_unit->gpio.irq, dev);
> > +}
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index 965a789ed03e..91ed59b54d9a 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -673,6 +673,9 @@ do { \
> > extern struct uvc_driver uvc_driver;
> >
> > struct uvc_entity *uvc_entity_by_id(struct uvc_device *dev, int id);
> > +struct uvc_entity *uvc_alloc_new_entity(struct uvc_device *dev, u16 type,
> > + u16 id, unsigned int num_pads,
> > + unsigned int extra_size);
> >
> > /* Video buffers queue management. */
> > int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
> > @@ -817,4 +820,9 @@ void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream);
> > size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
> > size_t size);
> >
> > +/* gpio */
> > +int uvc_gpio_parse(struct uvc_device *dev);
> > +int uvc_gpio_init_irq(struct uvc_device *dev);
> > +void uvc_gpio_deinit(struct uvc_device *dev);
> > +
> > #endif
> >
--
Regards,
Laurent Pinchart
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