From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86FEEC28CC0 for ; Thu, 30 May 2019 03:14:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 585452457C for ; Thu, 30 May 2019 03:14:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559186043; bh=RFEM2H8khOyd/ggh69UVrx3KhVVg1WNQLPmT6YZ1J14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dGL+ubeF+jXUoX8WK69A99Pvbs18gpBUsUVcARwoJjo8eX1ulz8a5yDPIv8WRXPCK 7Wqr3sNdS59W+lV01LFmHPu544MxvpTp+/VeHQAw/nDKI/ruZ5M/DIhl98Q246qauk FIQexKoC7NQLiwN/UgyrGqVCbtFx2gkWw4YQzNio= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729689AbfE3DOC (ORCPT ); Wed, 29 May 2019 23:14:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:52106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728693AbfE3DLt (ORCPT ); Wed, 29 May 2019 23:11:49 -0400 Received: from localhost (ip67-88-213-2.z213-88-67.customer.algx.net [67.88.213.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D8FFE2446F; Thu, 30 May 2019 03:11:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559185909; bh=RFEM2H8khOyd/ggh69UVrx3KhVVg1WNQLPmT6YZ1J14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vEd9OY2lV96YkYKTENI+9bVFQe/735ytnHrQOrKbCvLP6sgUlILrX9MVkguLQJhar NvFOCJ3H38EEOpCOXQCDrW4xIrQEE4pcE1JvWys4btiititZeadcwRHy2DPEweXg5Z YMkcamXKH7pK+h8PCJQDW1ftUgOsPiU7A4+7mYog= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Alexandru Ardelean , Jonathan Cameron , Sasha Levin Subject: [PATCH 5.1 240/405] iio: ad_sigma_delta: Properly handle SPI bus locking vs CS assertion Date: Wed, 29 May 2019 20:03:58 -0700 Message-Id: <20190530030553.145118974@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030540.291644921@linuxfoundation.org> References: <20190530030540.291644921@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit df1d80aee963480c5c2938c64ec0ac3e4a0df2e0 ] For devices from the SigmaDelta family we need to keep CS low when doing a conversion, since the device will use the MISO line as a interrupt to indicate that the conversion is complete. This is why the driver locks the SPI bus and when the SPI bus is locked keeps as long as a conversion is going on. The current implementation gets one small detail wrong though. CS is only de-asserted after the SPI bus is unlocked. This means it is possible for a different SPI device on the same bus to send a message which would be wrongfully be addressed to the SigmaDelta device as well. Make sure that the last SPI transfer that is done while holding the SPI bus lock de-asserts the CS signal. Signed-off-by: Lars-Peter Clausen Signed-off-by: Alexandru Ardelean Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/adc/ad_sigma_delta.c | 16 +++++++++++----- include/linux/iio/adc/ad_sigma_delta.h | 1 + 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c index 54d9978b27405..a4310600a8536 100644 --- a/drivers/iio/adc/ad_sigma_delta.c +++ b/drivers/iio/adc/ad_sigma_delta.c @@ -62,7 +62,7 @@ int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg, struct spi_transfer t = { .tx_buf = data, .len = size + 1, - .cs_change = sigma_delta->bus_locked, + .cs_change = sigma_delta->keep_cs_asserted, }; struct spi_message m; int ret; @@ -218,6 +218,7 @@ static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, spi_bus_lock(sigma_delta->spi->master); sigma_delta->bus_locked = true; + sigma_delta->keep_cs_asserted = true; reinit_completion(&sigma_delta->completion); ret = ad_sigma_delta_set_mode(sigma_delta, mode); @@ -235,9 +236,10 @@ static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, ret = 0; } out: + sigma_delta->keep_cs_asserted = false; + ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); sigma_delta->bus_locked = false; spi_bus_unlock(sigma_delta->spi->master); - ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); return ret; } @@ -290,6 +292,7 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, spi_bus_lock(sigma_delta->spi->master); sigma_delta->bus_locked = true; + sigma_delta->keep_cs_asserted = true; reinit_completion(&sigma_delta->completion); ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); @@ -299,9 +302,6 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, ret = wait_for_completion_interruptible_timeout( &sigma_delta->completion, HZ); - sigma_delta->bus_locked = false; - spi_bus_unlock(sigma_delta->spi->master); - if (ret == 0) ret = -EIO; if (ret < 0) @@ -322,7 +322,10 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, sigma_delta->irq_dis = true; } + sigma_delta->keep_cs_asserted = false; ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); + sigma_delta->bus_locked = false; + spi_bus_unlock(sigma_delta->spi->master); mutex_unlock(&indio_dev->mlock); if (ret) @@ -359,6 +362,8 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) spi_bus_lock(sigma_delta->spi->master); sigma_delta->bus_locked = true; + sigma_delta->keep_cs_asserted = true; + ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); if (ret) goto err_unlock; @@ -387,6 +392,7 @@ static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) sigma_delta->irq_dis = true; } + sigma_delta->keep_cs_asserted = false; ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); sigma_delta->bus_locked = false; diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h index 7e84351fa2c05..6e9fb1932dde9 100644 --- a/include/linux/iio/adc/ad_sigma_delta.h +++ b/include/linux/iio/adc/ad_sigma_delta.h @@ -69,6 +69,7 @@ struct ad_sigma_delta { bool irq_dis; bool bus_locked; + bool keep_cs_asserted; uint8_t comm; -- 2.20.1