From patchwork Fri Nov 8 14:07:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 11234923 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DCF821864 for ; Fri, 8 Nov 2019 14:07:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC32121D7B for ; Fri, 8 Nov 2019 14:07:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726616AbfKHOHx (ORCPT ); Fri, 8 Nov 2019 09:07:53 -0500 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:41603 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728835AbfKHOHx (ORCPT ); Fri, 8 Nov 2019 09:07:53 -0500 X-Originating-IP: 86.206.246.123 Received: from localhost.localdomain (lfbn-tou-1-421-123.w86-206.abo.wanadoo.fr [86.206.246.123]) (Authenticated sender: miquel.raynal@bootlin.com) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id D7FE920010; Fri, 8 Nov 2019 14:07:50 +0000 (UTC) From: Miquel Raynal To: Mark Brown , Michal Simek , Naga Sureshkumar Relli Cc: Thomas Petazzoni , , , Tudor Ambarus , Miquel Raynal Subject: [PATCH v2 5/7] spi: zynq-qspi: Clarify the select chip function Date: Fri, 8 Nov 2019 15:07:42 +0100 Message-Id: <20191108140744.1734-6-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191108140744.1734-1-miquel.raynal@bootlin.com> References: <20191108140744.1734-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org The code used to assert and de-assert a chip select line is very complicated for no reason. Simplify the logic by either setting or resetting the concerned bit, which actually only changes an electrical state. Update the comment to reflect that there is no possibility to actually choose a CS as the default (CS0) will be driven in any case. Signed-off-by: Miquel Raynal --- drivers/spi/spi-zynq-qspi.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c index 1151443ec830..9adfcc66b02b 100644 --- a/drivers/spi/spi-zynq-qspi.c +++ b/drivers/spi/spi-zynq-qspi.c @@ -51,7 +51,6 @@ #define ZYNQ_QSPI_CONFIG_BDRATE_MASK GENMASK(5, 3) /* Baud Rate Mask */ #define ZYNQ_QSPI_CONFIG_CPHA_MASK BIT(2) /* Clock Phase Control */ #define ZYNQ_QSPI_CONFIG_CPOL_MASK BIT(1) /* Clock Polarity Control */ -#define ZYNQ_QSPI_CONFIG_SSCTRL_MASK BIT(10) /* Slave Select Mask */ #define ZYNQ_QSPI_CONFIG_FWIDTH_MASK GENMASK(7, 6) /* FIFO width */ #define ZYNQ_QSPI_CONFIG_MSTREN_MASK BIT(0) /* Master Mode */ @@ -63,7 +62,7 @@ */ #define ZYNQ_QSPI_CONFIG_BAUD_DIV_MAX GENMASK(2, 0) /* Baud rate maximum */ #define ZYNQ_QSPI_CONFIG_BAUD_DIV_SHIFT 3 /* Baud rate divisor shift */ -#define ZYNQ_QSPI_CONFIG_PCS 10 /* Peripheral Chip Select */ +#define ZYNQ_QSPI_CONFIG_PCS BIT(10) /* Peripheral Chip Select */ /* * QSPI Interrupt Registers bit Masks @@ -288,16 +287,12 @@ static void zynq_qspi_chipselect(struct spi_device *spi, bool assert) struct zynq_qspi *xqspi = spi_controller_get_devdata(ctlr); u32 config_reg; + /* Ground the line to assert the CS */ config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET); - if (assert) { - /* Select the slave */ - config_reg &= ~ZYNQ_QSPI_CONFIG_SSCTRL_MASK; - config_reg |= (((~(BIT(spi->chip_select))) << - ZYNQ_QSPI_CONFIG_PCS) & - ZYNQ_QSPI_CONFIG_SSCTRL_MASK); - } else { - config_reg |= ZYNQ_QSPI_CONFIG_SSCTRL_MASK; - } + if (assert) + config_reg &= ~ZYNQ_QSPI_CONFIG_PCS; + else + config_reg |= ZYNQ_QSPI_CONFIG_PCS; zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg); }