From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2321CC43382 for ; Fri, 28 Sep 2018 06:44:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EB9EE2172C for ; Fri, 28 Sep 2018 06:44:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EB9EE2172C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728938AbeI1NHA (ORCPT ); Fri, 28 Sep 2018 09:07:00 -0400 Received: from mail.bootlin.com ([62.4.15.54]:43974 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728717AbeI1NG6 (ORCPT ); Fri, 28 Sep 2018 09:06:58 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 04527208F4; Fri, 28 Sep 2018 08:44:42 +0200 (CEST) Received: from bbrezillon (unknown [176.187.87.154]) by mail.bootlin.com (Postfix) with ESMTPSA id AE14520711; Fri, 28 Sep 2018 08:44:31 +0200 (CEST) Date: Fri, 28 Sep 2018 08:44:31 +0200 From: Boris Brezillon To: Chuanhua Han Cc: broonie@kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, eha@deif.com Subject: Re: [PATCH 1/2] spi: spi-mem: Add the spi_set_xfer_bpw function Message-ID: <20180928084431.300b7bf9@bbrezillon> In-Reply-To: <20180921070628.35153-1-chuanhua.han@nxp.com> References: <20180921070628.35153-1-chuanhua.han@nxp.com> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chuanhua, On Fri, 21 Sep 2018 15:06:26 +0800 Chuanhua Han wrote: > Before we add this spi_transfer to the spi_message chain table, we need > bits_per_word_mask based on spi_control to set the bits_per_word of > this spi_transfer. It's not clear to me what you're trying to fix/improve. Can you give more details on what the problem is? > > Signed-off-by: Chuanhua Han > --- > drivers/spi/spi-mem.c | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c > index eb72dba71d83..717e711c0952 100644 > --- a/drivers/spi/spi-mem.c > +++ b/drivers/spi/spi-mem.c > @@ -175,6 +175,41 @@ bool spi_mem_supports_op(struct spi_mem *mem, const struct spi_mem_op *op) > } > EXPORT_SYMBOL_GPL(spi_mem_supports_op); > > +/** > + * spi_set_xfer_bpw() - Set the bits_per_word for each transfer based on > + * the bits_per_word_mask of the spi controller > + * @ctrl: the spi controller > + * @xfer: the spi transfer > + * > + * This function sets the bits_per_word for each transfer based on the spi > + * controller's bits_per_word_mask to improve the efficiency of spi transport. > + * > + * Return: 0 in case of success, a negative error code otherwise. > + */ > +int spi_set_xfer_bpw(struct spi_controller *ctlr, struct spi_transfer *xfer) > +{ > + if (!ctlr || !xfer) { > + dev_err(&ctlr->dev, > + "Fail to set bits_per_word for spi transfer\n"); > + return -EINVAL; > + } > + > + if (ctlr->bits_per_word_mask) { > + if (!(xfer->len % 4)) { > + if (ctlr->bits_per_word_mask & SPI_BPW_MASK(32)) > + xfer->bits_per_word = 32; > + } else if (!(xfer->len % 2)) { > + if (ctlr->bits_per_word_mask & SPI_BPW_MASK(16)) > + xfer->bits_per_word = 16; > + } else { > + xfer->bits_per_word = 8; > + } > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(spi_set_xfer_bpw); Why is this function placed in spi-mem.c, and more importantly, why is it exported? > + > /** > * spi_mem_exec_op() - Execute a memory operation > * @mem: the SPI memory > @@ -252,6 +287,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) > xfers[xferpos].tx_buf = tmpbuf; > xfers[xferpos].len = sizeof(op->cmd.opcode); > xfers[xferpos].tx_nbits = op->cmd.buswidth; > + spi_set_xfer_bpw(ctlr, &xfers[xferpos]); It's still unclear why you need to specify a bits_per_word value, but if this is needed, it's probably something you want to add to spi.c, when a message is queued. > spi_message_add_tail(&xfers[xferpos], &msg); > xferpos++; > totalxferlen++; > @@ -266,6 +302,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) > xfers[xferpos].tx_buf = tmpbuf + 1; > xfers[xferpos].len = op->addr.nbytes; > xfers[xferpos].tx_nbits = op->addr.buswidth; > + spi_set_xfer_bpw(ctlr, &xfers[xferpos]); > spi_message_add_tail(&xfers[xferpos], &msg); > xferpos++; > totalxferlen += op->addr.nbytes; > @@ -276,6 +313,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) > xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1; > xfers[xferpos].len = op->dummy.nbytes; > xfers[xferpos].tx_nbits = op->dummy.buswidth; > + spi_set_xfer_bpw(ctlr, &xfers[xferpos]); > spi_message_add_tail(&xfers[xferpos], &msg); > xferpos++; > totalxferlen += op->dummy.nbytes; > @@ -291,6 +329,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) > } > > xfers[xferpos].len = op->data.nbytes; > + spi_set_xfer_bpw(ctlr, &xfers[xferpos]); > spi_message_add_tail(&xfers[xferpos], &msg); > xferpos++; > totalxferlen += op->data.nbytes;