| Message ID | 9c9c128b41e31d6bebe646e052aa05c44b19eb83.1627495116.git.ojaswin98@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | staging: vchiq: Minor fixups to CONFIG_VCHIQ_CDEV | expand |
On Thu, Jul 29, 2021 at 12:07:17AM +0530, Ojaswin Mujoo wrote: > Add some details to the Kconfig definition of $CONFIG_VCHIQ_CDEV to help > make the motive behind it a bit more clear. > > Signed-off-by: Ojaswin Mujoo <ojaswin98@gmail.com> > --- > drivers/staging/vc04_services/Kconfig | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/vc04_services/Kconfig b/drivers/staging/vc04_services/Kconfig > index 2b70c37cdd09..cb02d8a4cb74 100644 > --- a/drivers/staging/vc04_services/Kconfig > +++ b/drivers/staging/vc04_services/Kconfig > @@ -25,8 +25,12 @@ config VCHIQ_CDEV > bool "VCHIQ Character Driver" > default y > help > - Enable the creation of VCHIQ character driver to help > - communicate with the Videocore platform. > + Enable the creation of VCHIQ character driver to help communicate > + with the VideoCore platform. The cdev exposes ioctls used by > + userspace libraries and testing tools to interact with VideoCore. > + This can be set to 'N' if the VideoCore communication is not needed > + by userspace but only by other kernel modules (like bcm2835-audio). > + If not sure, set this to 'Y'. I still do not understand if I need this driver or not, and I have this hardware! What functionality does this driver accomplish? What is VideoCore? thanks, greg k-h
On Wed, Jul 28, 2021 at 08:46:51PM +0200, Greg KH wrote: > On Thu, Jul 29, 2021 at 12:07:17AM +0530, Ojaswin Mujoo wrote: > > Add some details to the Kconfig definition of $CONFIG_VCHIQ_CDEV to help > > make the motive behind it a bit more clear. > > > > Signed-off-by: Ojaswin Mujoo <ojaswin98@gmail.com> > > --- > > drivers/staging/vc04_services/Kconfig | 8 ++++++-- > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/staging/vc04_services/Kconfig b/drivers/staging/vc04_services/Kconfig > > index 2b70c37cdd09..cb02d8a4cb74 100644 > > --- a/drivers/staging/vc04_services/Kconfig > > +++ b/drivers/staging/vc04_services/Kconfig > > @@ -25,8 +25,12 @@ config VCHIQ_CDEV > > bool "VCHIQ Character Driver" > > default y > > help > > - Enable the creation of VCHIQ character driver to help > > - communicate with the Videocore platform. > > + Enable the creation of VCHIQ character driver to help communicate > > + with the VideoCore platform. The cdev exposes ioctls used by > > + userspace libraries and testing tools to interact with VideoCore. > > + This can be set to 'N' if the VideoCore communication is not needed > > + by userspace but only by other kernel modules (like bcm2835-audio). > > + If not sure, set this to 'Y'. > > I still do not understand if I need this driver or not, and I have this > hardware! What functionality does this driver accomplish? What is > VideoCore? Hey Greg, I believe I can add this under the CONFIG_BCM2835_VCHIQ config option, as that enables the core driver that implements the functions to communicate with VideoCore platform? This config option merely adds a cdev which exposes the the core driver's functionality to userspace. Regards, Ojaswin > > thanks, > > greg k-h
Am 28.07.21 um 22:00 schrieb Ojaswin Mujoo: > On Wed, Jul 28, 2021 at 08:46:51PM +0200, Greg KH wrote: >> On Thu, Jul 29, 2021 at 12:07:17AM +0530, Ojaswin Mujoo wrote: >>> Add some details to the Kconfig definition of $CONFIG_VCHIQ_CDEV to help >>> make the motive behind it a bit more clear. >>> >>> Signed-off-by: Ojaswin Mujoo <ojaswin98@gmail.com> >>> --- >>> drivers/staging/vc04_services/Kconfig | 8 ++++++-- >>> 1 file changed, 6 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/staging/vc04_services/Kconfig b/drivers/staging/vc04_services/Kconfig >>> index 2b70c37cdd09..cb02d8a4cb74 100644 >>> --- a/drivers/staging/vc04_services/Kconfig >>> +++ b/drivers/staging/vc04_services/Kconfig >>> @@ -25,8 +25,12 @@ config VCHIQ_CDEV >>> bool "VCHIQ Character Driver" >>> default y >>> help >>> - Enable the creation of VCHIQ character driver to help >>> - communicate with the Videocore platform. >>> + Enable the creation of VCHIQ character driver to help communicate >>> + with the VideoCore platform. The cdev exposes ioctls used by >>> + userspace libraries and testing tools to interact with VideoCore. >>> + This can be set to 'N' if the VideoCore communication is not needed >>> + by userspace but only by other kernel modules (like bcm2835-audio). >>> + If not sure, set this to 'Y'. >> I still do not understand if I need this driver or not, and I have this >> hardware! What functionality does this driver accomplish? What is >> VideoCore? > Hey Greg, > > I believe I can add this under the CONFIG_BCM2835_VCHIQ config option, > as that enables the core driver that implements the functions to > communicate with VideoCore platform? Sorry, today i'm too tired to give a good explanation. VideoCore is the VPU inside the BCM283x SoC. It runs a firmware and VCHIQ provides a way to communicate with this firmware / VPU. The VCHIQ driver is required to get access to the audio jack and camera interface (see depending drivers). Unfortunately i don't have an application list by the hand which uses the CDEV interface for VCHIQ, please use this link [1] as a starting point. [1] - https://github.com/raspberrypi/userland > > This config option merely adds a cdev which exposes the the core > driver's functionality to userspace. > > Regards, > Ojaswin >> thanks, >> >> greg k-h > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Wed, Jul 28, 2021 at 10:39:38PM +0200, Stefan Wahren wrote: > Am 28.07.21 um 22:00 schrieb Ojaswin Mujoo: > > On Wed, Jul 28, 2021 at 08:46:51PM +0200, Greg KH wrote: > >> On Thu, Jul 29, 2021 at 12:07:17AM +0530, Ojaswin Mujoo wrote: > >>> Add some details to the Kconfig definition of $CONFIG_VCHIQ_CDEV to help > >>> make the motive behind it a bit more clear. > >>> > >>> Signed-off-by: Ojaswin Mujoo <ojaswin98@gmail.com> > >>> --- > >>> drivers/staging/vc04_services/Kconfig | 8 ++++++-- > >>> 1 file changed, 6 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/drivers/staging/vc04_services/Kconfig b/drivers/staging/vc04_services/Kconfig > >>> index 2b70c37cdd09..cb02d8a4cb74 100644 > >>> --- a/drivers/staging/vc04_services/Kconfig > >>> +++ b/drivers/staging/vc04_services/Kconfig > >>> @@ -25,8 +25,12 @@ config VCHIQ_CDEV > >>> bool "VCHIQ Character Driver" > >>> default y > >>> help > >>> - Enable the creation of VCHIQ character driver to help > >>> - communicate with the Videocore platform. > >>> + Enable the creation of VCHIQ character driver to help communicate > >>> + with the VideoCore platform. The cdev exposes ioctls used by > >>> + userspace libraries and testing tools to interact with VideoCore. > >>> + This can be set to 'N' if the VideoCore communication is not needed > >>> + by userspace but only by other kernel modules (like bcm2835-audio). > >>> + If not sure, set this to 'Y'. > >> I still do not understand if I need this driver or not, and I have this > >> hardware! What functionality does this driver accomplish? What is > >> VideoCore? > > Hey Greg, > > > > I believe I can add this under the CONFIG_BCM2835_VCHIQ config option, > > as that enables the core driver that implements the functions to > > communicate with VideoCore platform? > > Sorry, today i'm too tired to give a good explanation. VideoCore is the > VPU inside the BCM283x SoC. It runs a firmware and VCHIQ provides a way > to communicate with this firmware / VPU. The VCHIQ driver is required to > get access to the audio jack and camera interface (see depending drivers). > > Unfortunately i don't have an application list by the hand which uses > the CDEV interface for VCHIQ, please use this link [1] as a starting point. > > [1] - https://github.com/raspberrypi/userland > Hi Stefan Thanks for the brief, its good enough to help me get started. I've also been looking more closely into this driver in my free time lately and I can try to come up with a small summary to use as the help text. I'll add it in v2 of this patch. Regards, Ojaswin > > > > This config option merely adds a cdev which exposes the the core > > driver's functionality to userspace. > > > > Regards, > > Ojaswin > >> thanks, > >> > >> greg k-h > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
diff --git a/drivers/staging/vc04_services/Kconfig b/drivers/staging/vc04_services/Kconfig index 2b70c37cdd09..cb02d8a4cb74 100644 --- a/drivers/staging/vc04_services/Kconfig +++ b/drivers/staging/vc04_services/Kconfig @@ -25,8 +25,12 @@ config VCHIQ_CDEV bool "VCHIQ Character Driver" default y help - Enable the creation of VCHIQ character driver to help - communicate with the Videocore platform. + Enable the creation of VCHIQ character driver to help communicate + with the VideoCore platform. The cdev exposes ioctls used by + userspace libraries and testing tools to interact with VideoCore. + This can be set to 'N' if the VideoCore communication is not needed + by userspace but only by other kernel modules (like bcm2835-audio). + If not sure, set this to 'Y'. endif
Add some details to the Kconfig definition of $CONFIG_VCHIQ_CDEV to help make the motive behind it a bit more clear. Signed-off-by: Ojaswin Mujoo <ojaswin98@gmail.com> --- drivers/staging/vc04_services/Kconfig | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)