From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752947AbcAEUqk (ORCPT ); Tue, 5 Jan 2016 15:46:40 -0500 Received: from mail-wm0-f47.google.com ([74.125.82.47]:34355 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956AbcAEUqf (ORCPT ); Tue, 5 Jan 2016 15:46:35 -0500 From: Marcus Weseloh To: linux-sunxi@googlegroups.com Cc: Marcus Weseloh , Mark Brown , Maxime Ripard , Chen-Yu Tsai , linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] spi: sun4i: Prevent chip-select from being activated twice before a transfer Date: Tue, 5 Jan 2016 21:46:20 +0100 Message-Id: <1452026780-8819-1-git-send-email-mweseloh42@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The SPI core calls set_cs before a transfer, but the SUN4I_CTL_CS_MANUAL flag is only set in transfer_one. This leads to the following pattern on the chip-select line (with runtime power-management on every transfer, without it only on the first one): activate, deactivate, activate, transfer, deactivate Moving the configuration of the SUN4I_CTL_CS_MANUAL flag from transfer_one to set_cs removes the double activation. Signed-off-by: Marcus Weseloh Acked-by: Maxime Ripard --- Changes from v1: - Added Maximes Acked-by --- drivers/spi/spi-sun4i.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c index fbb0a4d..a6d936c 100644 --- a/drivers/spi/spi-sun4i.c +++ b/drivers/spi/spi-sun4i.c @@ -140,6 +140,9 @@ static void sun4i_spi_set_cs(struct spi_device *spi, bool enable) reg &= ~SUN4I_CTL_CS_MASK; reg |= SUN4I_CTL_CS(spi->chip_select); + /* We want to control the chip select manually */ + reg |= SUN4I_CTL_CS_MANUAL; + if (enable) reg |= SUN4I_CTL_CS_LEVEL; else @@ -222,9 +225,6 @@ static int sun4i_spi_transfer_one(struct spi_master *master, else reg |= SUN4I_CTL_DHB; - /* We want to control the chip select manually */ - reg |= SUN4I_CTL_CS_MANUAL; - sun4i_spi_write(sspi, SUN4I_CTL_REG, reg); /* Ensure that we have a parent clock fast enough */ -- 1.9.1