From patchwork Thu Apr 16 20:54:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Belloni X-Patchwork-Id: 11493749 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 EDE9D6CA for ; Thu, 16 Apr 2020 20:54:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF5FE221F7 for ; Thu, 16 Apr 2020 20:54:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728385AbgDPUyh (ORCPT ); Thu, 16 Apr 2020 16:54:37 -0400 Received: from relay10.mail.gandi.net ([217.70.178.230]:54883 "EHLO relay10.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728315AbgDPUyh (ORCPT ); Thu, 16 Apr 2020 16:54:37 -0400 Received: from localhost (lfbn-lyo-1-9-35.w86-202.abo.wanadoo.fr [86.202.105.35]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay10.mail.gandi.net (Postfix) with ESMTPSA id 00A58240003; Thu, 16 Apr 2020 20:54:31 +0000 (UTC) From: Alexandre Belloni To: Jonathan Cameron Cc: Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Gregory CLEMENT , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Alexandre Belloni Subject: [PATCH v2 1/2] iio: adc: ti-ads8344: properly byte swap value Date: Thu, 16 Apr 2020 22:54:27 +0200 Message-Id: <20200416205428.437503-2-alexandre.belloni@bootlin.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200416205428.437503-1-alexandre.belloni@bootlin.com> References: <20200416205428.437503-1-alexandre.belloni@bootlin.com> MIME-Version: 1.0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The first received byte is the MSB, followed by the LSB so the value needs to be byte swapped. Also, the ADC actually has a delay of one clock on the SPI bus. Read three bytes to get the last bit. Fixes: 8dd2d7c0fed7 ("iio: adc: Add driver for the TI ADS8344 A/DC chips") Signed-off-by: Alexandre Belloni --- drivers/iio/adc/ti-ads8344.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/iio/adc/ti-ads8344.c b/drivers/iio/adc/ti-ads8344.c index 9a460807d46d..abe4b56c847c 100644 --- a/drivers/iio/adc/ti-ads8344.c +++ b/drivers/iio/adc/ti-ads8344.c @@ -29,7 +29,7 @@ struct ads8344 { struct mutex lock; u8 tx_buf ____cacheline_aligned; - u16 rx_buf; + u8 rx_buf[3]; }; #define ADS8344_VOLTAGE_CHANNEL(chan, si) \ @@ -89,11 +89,11 @@ static int ads8344_adc_conversion(struct ads8344 *adc, int channel, udelay(9); - ret = spi_read(spi, &adc->rx_buf, 2); + ret = spi_read(spi, adc->rx_buf, sizeof(adc->rx_buf)); if (ret) return ret; - return adc->rx_buf; + return adc->rx_buf[0] << 9 | adc->rx_buf[1] << 1 | adc->rx_buf[2] >> 7; } static int ads8344_read_raw(struct iio_dev *iio, From patchwork Thu Apr 16 20:54:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Belloni X-Patchwork-Id: 11493751 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 9BC4A6CA for ; Thu, 16 Apr 2020 20:54:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E271206D5 for ; Thu, 16 Apr 2020 20:54:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728293AbgDPUyf (ORCPT ); Thu, 16 Apr 2020 16:54:35 -0400 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:39851 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726725AbgDPUyf (ORCPT ); Thu, 16 Apr 2020 16:54:35 -0400 X-Originating-IP: 86.202.105.35 Received: from localhost (lfbn-lyo-1-9-35.w86-202.abo.wanadoo.fr [86.202.105.35]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 288F4FF805; Thu, 16 Apr 2020 20:54:33 +0000 (UTC) From: Alexandre Belloni To: Jonathan Cameron Cc: Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Gregory CLEMENT , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Alexandre Belloni Subject: [PATCH v2 2/2] iio: adc: ti-ads8344: optimize consumption Date: Thu, 16 Apr 2020 22:54:28 +0200 Message-Id: <20200416205428.437503-3-alexandre.belloni@bootlin.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200416205428.437503-1-alexandre.belloni@bootlin.com> References: <20200416205428.437503-1-alexandre.belloni@bootlin.com> MIME-Version: 1.0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Set the clock mode only once, at probe time and then keep the ADC powered down between conversions. Signed-off-by: Alexandre Belloni --- drivers/iio/adc/ti-ads8344.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/iio/adc/ti-ads8344.c b/drivers/iio/adc/ti-ads8344.c index abe4b56c847c..40e7a9eee189 100644 --- a/drivers/iio/adc/ti-ads8344.c +++ b/drivers/iio/adc/ti-ads8344.c @@ -72,7 +72,7 @@ static const struct iio_chan_spec ads8344_channels[] = { }; static int ads8344_adc_conversion(struct ads8344 *adc, int channel, - bool differential) + bool differential, u8 clock) { struct spi_device *spi = adc->spi; int ret; @@ -81,7 +81,7 @@ static int ads8344_adc_conversion(struct ads8344 *adc, int channel, if (!differential) adc->tx_buf |= ADS8344_SINGLE_END; adc->tx_buf |= ADS8344_CHANNEL(channel); - adc->tx_buf |= ADS8344_CLOCK_INTERNAL; + adc->tx_buf |= clock; ret = spi_write(spi, &adc->tx_buf, 1); if (ret) @@ -106,7 +106,7 @@ static int ads8344_read_raw(struct iio_dev *iio, case IIO_CHAN_INFO_RAW: mutex_lock(&adc->lock); *value = ads8344_adc_conversion(adc, channel->scan_index, - channel->differential); + channel->differential, 0); mutex_unlock(&adc->lock); if (*value < 0) return *value; @@ -161,6 +161,11 @@ static int ads8344_probe(struct spi_device *spi) if (ret) return ret; + /* Do a dummy read and set external clock mode */ + ret = ads8344_adc_conversion(adc, 0, 0, ADS8344_CLOCK_INTERNAL); + if (ret < 0) + return ret; + spi_set_drvdata(spi, indio_dev); ret = iio_device_register(indio_dev);