From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH 2/2] dmaengine: Add STM32 MDMA driver Date: Mon, 1 May 2017 11:42:30 +0530 Message-ID: <20170501061230.GP6263@localhost> References: <1489417599-31308-1-git-send-email-cedric.madianga@gmail.com> <1489417599-31308-3-git-send-email-cedric.madianga@gmail.com> <20170406070805.GG4094@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Pierre Yves MORDRET Cc: M'boumba Cedric Madianga , "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , Alexandre TORGUE , "linux-kernel@vger.kernel.org" , "robh+dt@kernel.org" , "mcoquelin.stm32@gmail.com" , "dmaengine@vger.kernel.org" , "dan.j.williams@intel.com" , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org On Wed, Apr 26, 2017 at 12:35:46PM +0000, Pierre Yves MORDRET wrote: > On 04/06/2017 09:08 AM, Vinod Koul wrote: > >> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan, > >> + enum dma_slave_buswidth width) > >> +{ > >> + switch (width) { > >> + case DMA_SLAVE_BUSWIDTH_1_BYTE: > >> + return STM32_MDMA_BYTE; > >> + case DMA_SLAVE_BUSWIDTH_2_BYTES: > >> + return STM32_MDMA_HALF_WORD; > >> + case DMA_SLAVE_BUSWIDTH_4_BYTES: > >> + return STM32_MDMA_WORD; > >> + case DMA_SLAVE_BUSWIDTH_8_BYTES: > >> + return STM32_MDMA_DOUBLE_WORD; > > > > IIUC we can do this with ffs() > > I don't believe we can do that. This function translates DMA_SLAVE enum > into internal register representation. Yes and internal represenation seemed to be ffs() of dmanegine one. > >> +subsys_initcall(stm32_mdma_init); > > > > why subsys? > > > > subsys_initcall level is to ensure MDMA is going to be probed before its > clients Please use deffered probe approach for that -- ~Vinod