From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751610AbaANLfG (ORCPT ); Tue, 14 Jan 2014 06:35:06 -0500 Received: from jacques.telenet-ops.be ([195.130.132.50]:38965 "EHLO jacques.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751367AbaANLfB (ORCPT ); Tue, 14 Jan 2014 06:35:01 -0500 From: Geert Uytterhoeven To: Mark Brown Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH] spi: Clarify (a)synchronous transfer_one() Date: Tue, 14 Jan 2014 12:34:56 +0100 Message-Id: <1389699296-28994-1-git-send-email-geert@linux-m68k.org> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Geert Uytterhoeven Signed-off-by: Geert Uytterhoeven --- include/linux/spi/spi.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 21a7251d85ee..5319a8510921 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -282,10 +282,12 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @prepare_message: set up the controller to transfer a single message, * for example doing DMA mapping. Called from threaded * context. - * @transfer_one: transfer a single spi_transfer. When the - * driver is finished with this transfer it must call - * spi_finalize_current_transfer() so the subsystem can issue - * the next transfer + * @transfer_one: transfer a single spi_transfer. + * Synchronous transfer methods must return 0 on success. + * Asynchronous transfer methods must return a strict-positive + * value on successful submission, and must call + * spi_finalize_current_transfer() when the driver is finished + * so the subsystem can issue the next transfer * @unprepare_message: undo any work done by prepare_message(). * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS * number. Any individual value may be -ENOENT for CS lines that -- 1.7.9.5