From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f173.google.com (mail-pl1-f173.google.com [209.85.214.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A7D963481 for ; Thu, 29 Jul 2021 13:48:03 +0000 (UTC) Received: by mail-pl1-f173.google.com with SMTP id d1so7079891pll.1 for ; Thu, 29 Jul 2021 06:48:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=YxDl0EJtEuevrE5fofbeNq+CYZb2RNB0hzvmFi+D3+8=; b=VVYQWyDfexTZ8+hbjdrXcso8HsN0LxWI8d3EnEupkmGdjIekJNRNOUnHbFvjHQDSTL sZoJ3mohHFdq5D2OsrU4VkIxYb/jwD1NqYsCFKcuiaJsDikdI1VcNWref2GZYaczSIcC NOTsJIA8uiNJpcfNMMN1iXroctoHxObztJZabghMQl6xFYmo4Qlzughg4rtXT18uK6KM d0aPBsBM8+KsN368qpHnjjYYnNTZzox1aN8Q6rLKlpCpYG9RgA0oDbQHV+KErlpqWAk+ IA20Mz8OUyk7fSs7EtQl+Hi52so/NY/jNIRcLNuRaTqXyR5Xofhh3dpX1NReIcRUQG2i JcQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=YxDl0EJtEuevrE5fofbeNq+CYZb2RNB0hzvmFi+D3+8=; b=lKuYXT3aiyFxLqujGmCyaeqMWy3c1UOr7CUsgXbXZGP4rgYeKQ9vG4BF4ew/xiXRWd /QBeHA/+aELrDuCbnqmsXPG9PjRCi06dTCep8XDJj712ZREADY9g2r/lqDUoXqGMymoX nnFsL1+HeSCeA/V2Ya0RI/c55GoyQpCJPveWQ5ZtHa8r0b7lDPfhN6lmC1Q2fG+YVJPc fEa8Rt7S54NeJBjRDNKN9aB/LEE+o2gHKUuKgv+KTAdqZcisY6X8eYRHl0qP6pPpBZpC TPNc4By27+WfKkFj1kflP+A9/oknOKSwy5vn7oMwDkXK4meTvhpMG14bDAQFCPQmxJBb Z4BQ== X-Gm-Message-State: AOAM530Qxxe6Uwu9JlW6PLKwr50UjDzVKueHu/khpaWfgmbie63WrVip 1V1wsDAVI19RKLsfLSycCqQ= X-Google-Smtp-Source: ABdhPJwehJhh8ZtlX4s5039UfLl8M70E/Prup4jVkYNGctW420GGbrH/QI/TZ7Pczmv/94fnJzaTHg== X-Received: by 2002:a17:90a:b893:: with SMTP id o19mr5325862pjr.114.1627566483247; Thu, 29 Jul 2021 06:48:03 -0700 (PDT) Received: from ojas ([122.161.51.5]) by smtp.gmail.com with ESMTPSA id f3sm3887725pfe.123.2021.07.29.06.47.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jul 2021 06:48:02 -0700 (PDT) Date: Thu, 29 Jul 2021 19:17:52 +0530 From: Ojaswin Mujoo To: Stefan Wahren Cc: Greg KH , nsaenz@kernel.org, dan.carpenter@oracle.com, phil@raspberrypi.com, linux-arm-kernel@lists.infradead.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] staging: vchiq: Add details to $CONFIG_VCHIQ_CDEV help text Message-ID: <20210729134739.GA19228@ojas> References: <9c9c128b41e31d6bebe646e052aa05c44b19eb83.1627495116.git.ojaswin98@gmail.com> <20210728200039.GA17046@ojas> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 > >>> --- > >>> 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 >