From patchwork Sat Feb 23 08:49:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Sperl X-Patchwork-Id: 10827351 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 028A71399 for ; Sat, 23 Feb 2019 08:50:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E440D2F9F1 for ; Sat, 23 Feb 2019 08:50:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D88F130CCE; Sat, 23 Feb 2019 08:50:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7E9762F9F1 for ; Sat, 23 Feb 2019 08:50:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726326AbfBWIuN (ORCPT ); Sat, 23 Feb 2019 03:50:13 -0500 Received: from 212-186-180-163.static.upcbusiness.at ([212.186.180.163]:47824 "EHLO cgate.sperl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726043AbfBWIuN (ORCPT ); Sat, 23 Feb 2019 03:50:13 -0500 Received: from hc1.intern.sperl.org (account martin@sperl.org [10.10.10.59] verified) by sperl.org (CommuniGate Pro SMTP 6.2.1 _community_) with ESMTPSA id 7757393; Sat, 23 Feb 2019 08:50:05 +0000 From: kernel@martin.sperl.org To: Mark Brown , Eric Anholt , Stefan Wahren , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Martin Sperl Subject: [PATCH 3/5] spi: core: allow defining time that cs is deasserted as a multiple of SCK Date: Sat, 23 Feb 2019 08:49:50 +0000 Message-Id: <20190223084952.14758-4-kernel@martin.sperl.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190223084952.14758-1-kernel@martin.sperl.org> References: <20190223084952.14758-1-kernel@martin.sperl.org> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Martin Sperl Support setting a delay between cs assert and deassert as a multiple of spi clock length. Signed-off-by: Martin Sperl --- drivers/spi/spi.c | 8 ++++++++ include/linux/spi/spi.h | 1 + 2 files changed, 9 insertions(+) -- 2.11.0 diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 5a4616894d57..d5259bdd4b88 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1092,6 +1092,7 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg, { u32 delay = xfer->cs_change_delay; u32 unit = xfer->cs_change_delay_unit; + u32 hz; /* return early on "fast" mode - for everything but USECS */ if (!delay && unit != SPI_DELAY_UNIT_USECS) @@ -1107,6 +1108,13 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg, break; case SPI_DELAY_UNIT_NSECS: /* nothing to do here */ break; + case SPI_DELAY_UNIT_SCK: + /* if there is no effective speed know, then approximate + * by underestimating with half the requested hz + */ + hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2; + delay *= DIV_ROUND_UP(1000000000, hz); + break; default: dev_err_once(&msg->spi->dev, "Use of unsupported delay unit %i, using default of 10us\n", diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index f503a712423d..0b1d5e2b8b8b 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -799,6 +799,7 @@ struct spi_transfer { u8 cs_change_delay_unit; #define SPI_DELAY_UNIT_USECS 0 #define SPI_DELAY_UNIT_NSECS 1 +#define SPI_DELAY_UNIT_SCK 2 u32 speed_hz; u16 word_delay;