From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Murphy Subject: Re: [PATCH 2/2] can: tcan4x5x: Add tcan4x5x driver to the kernel Date: Fri, 5 Oct 2018 06:45:38 -0500 Message-ID: <5e0d5a5b-dfe0-a2b5-8ca2-733579bda216@ti.com> References: <20180910201241.24092-1-dmurphy@ti.com> <20180910201241.24092-2-dmurphy@ti.com> <631340c2-78a6-eec3-0ab2-713dddd8e84f@ti.com> <45621ef7-bc87-3d1e-efca-e6387fdebf9a@grandegger.com> <7a75a096-d07f-693e-74b6-74a76c00acf5@ti.com> <6f055cd9-9452-0b4c-2df2-3d0cc06f9e68@grandegger.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: , , , "Mario.Huettel" To: Wolfgang Grandegger , , Return-path: In-Reply-To: <6f055cd9-9452-0b4c-2df2-3d0cc06f9e68@grandegger.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Wolfgang On 10/05/2018 12:56 AM, Wolfgang Grandegger wrote: > Hello Dan, > > Am 04.10.2018 um 22:26 schrieb Dan Murphy: >> Wolfgang >> >> On 09/26/2018 12:54 PM, Wolfgang Grandegger wrote: >>> Hello, >>> >>> I wonder why you do not extend the existing MCAN driver by implementing >>> an interface to access the hardware. Would that be feasible? >>> >> >> I have created a m_can_core code base that can be used by other hardware that >> have special needs. >> >> So I have created the m_can_core, m_can and the tcan4x5x drivers. > > Great, I still think it's a good idea to have just one "m_can" driver. The m_can and tcan4x5x provide the device level implementations. The m_can_core deals specifically with handling of the m_can IP and protocol. > >> I can RFC the code to see if this is what is expected. >> It is not 100% working but it is close enough for a directional call. > > That would be nice! Most of the SPI accesses are pure register accesses. > A few read/write more bytes at a time (for data, etc.) but that could be > handled by appropriate interface functions. One general problem is that > SPI accesses are not possible from interrupt context requiring threads > or work queues. Also NAPI is usually not used. > > Other opinions? agreed. Is there any issue with moving the request_irq to a threaded_irq? Not sure how that would affect the timing. > > Wolfgang. > > PS: I have added Mario to the CC. Maybe he could test a common driver on > his M_CAN hardware. > I found that our am5/dra76 EVM also uses this IP stack. So I am working with our experts there to test and review the code as well. Dan -- ------------------ Dan Murphy