From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tmnt04.transmode.se (147.175.241.83.in-addr.dgcsystems.net [83.241.175.147]) by ozlabs.org (Postfix) with ESMTP id 0262867BF7 for ; Thu, 14 Dec 2006 02:36:05 +1100 (EST) From: "Joakim Tjernlund" To: "'Kumar Gala'" Subject: RE: [PATCH] Adapt spi_mpc83xx SPI driver for 832x Date: Wed, 13 Dec 2006 16:36:00 +0100 Message-ID: <032a01c71ecc$659ae480$020120ac@Jocke> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <5CD24382-201C-4B60-B410-3746A032415A@kernel.crashing.org> Cc: 'linuxppc-dev Development' , spi-devel-general@lists.sourceforge.net List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > -----Original Message----- > From: Kumar Gala [mailto:galak@kernel.crashing.org] > Sent: den 13 december 2006 15:46 > To: joakim.tjernlund@transmode.se > Cc: linuxppc-dev Development; spi-devel-general@lists.sourceforge.net > Subject: Re: [PATCH] Adapt spi_mpc83xx SPI driver for 832x > > > On Dec 13, 2006, at 3:22 AM, Joakim Tjernlund wrote: > > > The MPC 832x has a different SPI controller i/f, probably due to > > its QUICC engine support. This patch adapts the spi_mpx83xx > driver to > > be usable on QE based 83xx cpus. > > > > Jocke > > One problem I have with this patch is the fact that it assumes the > current driver for (mpc834x) and your mods to support mpc832x/QE are > mutually exclusive. I don't see that as a problem ATM. If that is added it should be optional. > > We need to handle the case of having driver support for both the QE > and MPC834x style in the same kernel. Adding that will double the number RX_BUF/TX_BUF functions from 6 to 12 (possibly this can be reduced by adding more logic to the tx_buf/rx_buf functions) not to mention what will happen when support for reversed bit order is added. I would argue that the kernel lacks the possibility to remove complexity I don't need. Example in this driver is that there is no way to remove support for 16 and 32 bit SPI character sizes. The same goes for a lot of the probing code in fsl-soc.c. It would be nice if a board port could add a custom header file that gets included by all .c automatically. Then one could add knobs (read #defines) there to futher tune such things as SPI char size. That way one don't have add Kconfig entries for all those small tuning knobs. Jocke