From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laxman Dewangan Subject: Re: How to correctly use spi_slave_tegra Date: Thu, 15 Nov 2012 18:23:05 -0500 Message-ID: <50A57959.1040208@nvidia.com> References: <3877625.uASAU6TrGF@number-5> <50A538DA.2010906@wwwdotorg.org> <50A53CB7.1090705@nvidia.com> <2843691.9Zl65ZOxsQ@number-5> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <2843691.9Zl65ZOxsQ@number-5> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Federico Vaga Cc: Stephen Warren , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "a.sappia-197Af0g7QoUlk5EcyZIkJQ@public.gmane.org" , "puria.nafisi-yFROiS3d6cY@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On 11/15/2012 02:41 PM, Federico Vaga wrote: >> Yes, the above are correct. The way we wrote the driver is that to >> support the sync and async both. >> When driver configures spi controller and ready for receive data then >> the callback from client is called. This callback is registered through >> spi_tegra_register_callback(). The client code then can inform master in >> this callback to start transfer through some mechanism i.e. gpio. > One more question. > From the Tegra 2 Manual, SPI slave section, I read (I cannot copy it because > of DRM and Nvidia legal stuff) that the clock signal *must* has 1 cycle delay > between each word (or packet in packet mode); but I don't read from the master > section that the master controller provide 1 cycle delay between each word (or > packet). If I connect a Tegra 2 SPI Master with a Tegra 2 SPI slave .... it > works? > Aah, it is something written incorrectly. We had internal discussion to remove this statement from TRM already. Please ignore the 1 cycle delay statement.