Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753376AbaKQWuc (ORCPT ); Mon, 17 Nov 2014 17:50:32 -0500 Received: from mail-wg0-f54.google.com ([74.125.82.54]:44159 "EHLO mail-wg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752999AbaKQWu3 (ORCPT ); Mon, 17 Nov 2014 17:50:29 -0500 From: Beniamino Galvani To: Mark Brown Cc: linux-spi@vger.kernel.org, Carlo Caione , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Russell King , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Jerry Cao , Victor Wan , Beniamino Galvani Subject: [PATCH v2 1/4] spi: Add 'last' flag to spi_transfer structure Date: Mon, 17 Nov 2014 23:47:48 +0100 Message-Id: <1416264471-774-2-git-send-email-b.galvani@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1416264471-774-1-git-send-email-b.galvani@gmail.com> References: <1416264471-774-1-git-send-email-b.galvani@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some drivers need to know whether the current transfer is the last in the message in order to properly handle CS. A common way to achieve this is to reimplement transfer_one_message() but this leads to undesirable code duplication. This patch adds a 'last' field to the spi_transfer structure and populates it before passing the structure to the driver. Signed-off-by: Beniamino Galvani --- drivers/spi/spi.c | 6 ++++++ include/linux/spi/spi.h | 2 ++ 2 files changed, 8 insertions(+) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index ebcb33d..fc7f02d 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -887,6 +887,7 @@ static void spi_pump_messages(struct kthread_work *work) { struct spi_master *master = container_of(work, struct spi_master, pump_messages); + struct spi_transfer *xfer; unsigned long flags; bool was_busy = false; int ret; @@ -941,6 +942,11 @@ static void spi_pump_messages(struct kthread_work *work) } } + list_for_each_entry(xfer, &master->cur_msg->transfers, transfer_list) { + xfer->last = list_is_last(&xfer->transfer_list, + &master->cur_msg->transfers); + } + if (!was_busy) trace_spi_master_busy(master); diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 46d188a..37f055a 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -535,6 +535,7 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum); * (SPI_NBITS_SINGLE) is used. * @rx_nbits: number of bits used for reading. If 0 the default * (SPI_NBITS_SINGLE) is used. + * @last: whether the transfer is the last in the message. * @len: size of rx and tx buffers (in bytes) * @speed_hz: Select a speed other than the device default for this * transfer. If 0 the default (from @spi_device) is used. @@ -620,6 +621,7 @@ struct spi_transfer { unsigned cs_change:1; unsigned tx_nbits:3; unsigned rx_nbits:3; + unsigned last:1; #define SPI_NBITS_SINGLE 0x01 /* 1bit transfer */ #define SPI_NBITS_DUAL 0x02 /* 2bits transfer */ #define SPI_NBITS_QUAD 0x04 /* 4bits transfer */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/