From patchwork Tue Jul 13 04:34:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liam Beguin X-Patchwork-Id: 12372757 X-Patchwork-Delegate: jic23@cam.ac.uk 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 9749FC11F6A for ; Tue, 13 Jul 2021 04:34:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 73E8C6100C for ; Tue, 13 Jul 2021 04:34:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230254AbhGMEhn (ORCPT ); Tue, 13 Jul 2021 00:37:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229995AbhGMEh1 (ORCPT ); Tue, 13 Jul 2021 00:37:27 -0400 Received: from mail-qv1-xf34.google.com (mail-qv1-xf34.google.com [IPv6:2607:f8b0:4864:20::f34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E80EC0613DD; Mon, 12 Jul 2021 21:34:37 -0700 (PDT) Received: by mail-qv1-xf34.google.com with SMTP id h18so9751280qve.1; Mon, 12 Jul 2021 21:34:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=sPst0AOe1AQCYOq/F7geIJMMQOaSZ1mUrw6X55zyTro=; b=RjSLFtYOAR6jqXxMDMCwJOkqjpQ2WD26wahtuiA8QAb8QalANJQjOE2uqIRQ2DG5bI NDyUx+qfI/GZ9lgank/IMKkrt68JL+9Pk7yV/VbxbgVdxLT64KN5m5C3d1iq776dsKmv Ha6Yaq5npuqeW7MJqwnRJ/EGlu34YGkQvCpPggUln9P6KIgF60rUu/bEsYKn+ga62zsC B137oUx2TWgNDtO9LIewmKOteh25RMHtlcl6kBOYuc+aG7w5RAvxkpSDt6eMWExjRbEx KzGfHmEQik452fIZnZtNLacy4T6z9g+uSggAlBolFt68E59r7djFvwRYbU7Ipd15d3R6 ebQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=sPst0AOe1AQCYOq/F7geIJMMQOaSZ1mUrw6X55zyTro=; b=gn6kPYfEfU4E+x+zPbRkLwFxZFfgdX4w02kUiC5HysgXcRfuosW8mmDi/MYTfkj97q lpCKP2I19ktawGcrTnq4S6bxk+YCESi3zESFCmYVKkGRXP/GNu8OjdwJ+TICiXrGCOCN yHTPGUCffHkqH8g81Cr+5R0an3+UrJmKkYHbItzuyMxzjmrLttKWGhTq0AdqQEfMePzp +ImXUZrMDwkKY3h/6b87TvVgfYyFECVKEyfa8RE8E34s1ZkXxp4qA2sISuruuddo5Mzm /8sz6XAxEYSZkLYwgXXiV5xL7TjgYlo+QIQm5BLG3C/vjXxbYSaWCl+/ycNn//mzAGmo a8tQ== X-Gm-Message-State: AOAM533v7NOAsEt1P/cwe48i8xTnJZoAesRGl9xPtzgORq5/Fye7O99J eJnVCIlgvOY4vwbdxToCLt0= X-Google-Smtp-Source: ABdhPJziAkj5OokxK1f1pbkRgjq3RkEjWcUQsrYYhMZxFVybSuzi/uadGT95l4MIAHM2+QS19Dy6Mw== X-Received: by 2002:a05:6214:172:: with SMTP id y18mr2795217qvs.14.1626150876721; Mon, 12 Jul 2021 21:34:36 -0700 (PDT) Received: from shaak.xiphos.ca (198-48-202-89.cpe.pppoe.ca. [198.48.202.89]) by smtp.gmail.com with ESMTPSA id x16sm7311455qkn.130.2021.07.12.21.34.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jul 2021 21:34:36 -0700 (PDT) From: Liam Beguin To: liambeguin@gmail.com, lars@metafoo.de, Michael.Hennerich@analog.com, jic23@kernel.org, charles-antoine.couret@essensium.com, Nuno.Sa@analog.com Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org Subject: [PATCH v3 2/4] iio: adc: ad7949: fix spi messages on non 14-bit controllers Date: Tue, 13 Jul 2021 00:34:23 -0400 Message-Id: <20210713043425.3321230-3-liambeguin@gmail.com> X-Mailer: git-send-email 2.30.1.489.g328c10930387 In-Reply-To: <20210713043425.3321230-1-liambeguin@gmail.com> References: <20210713043425.3321230-1-liambeguin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Liam Beguin This driver supports devices with 14-bit and 16-bit sample sizes. This is not always handled properly by spi controllers and can fail. To work around this limitation, pad samples to 16-bit and split the sample into two 8-bit messages in the event that only 8-bit messages are supported by the controller. Signed-off-by: Liam Beguin --- drivers/iio/adc/ad7949.c | 68 +++++++++++++++++++++++++++++++++++----- 1 file changed, 60 insertions(+), 8 deletions(-) diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c index 0b549b8bd7a9..65f78751225b 100644 --- a/drivers/iio/adc/ad7949.c +++ b/drivers/iio/adc/ad7949.c @@ -12,6 +12,7 @@ #include #include #include +#include #define AD7949_MASK_TOTAL GENMASK(13, 0) @@ -67,6 +68,7 @@ static const struct ad7949_adc_spec ad7949_adc_spec[] = { * @indio_dev: reference to iio structure * @spi: reference to spi structure * @resolution: resolution of the chip + * @bits_per_word: number of bits per SPI word * @cfg: copy of the configuration register * @current_channel: current channel in use * @buffer: buffer to send / receive data to / from device @@ -77,6 +79,7 @@ struct ad7949_adc_chip { struct iio_dev *indio_dev; struct spi_device *spi; u8 resolution; + u8 bits_per_word; u16 cfg; unsigned int current_channel; u16 buffer ____cacheline_aligned; @@ -86,19 +89,37 @@ static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc, u16 val, u16 mask) { int ret; - int bits_per_word = ad7949_adc->resolution; - int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS; + u8 buf8[2]; struct spi_message msg; struct spi_transfer tx[] = { { .tx_buf = &ad7949_adc->buffer, .len = 2, - .bits_per_word = bits_per_word, + .bits_per_word = ad7949_adc->bits_per_word, }, }; + ad7949_adc->buffer = 0; ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask); - ad7949_adc->buffer = ad7949_adc->cfg << shift; + + switch (ad7949_adc->bits_per_word) { + case 16: + ad7949_adc->buffer = ad7949_adc->cfg << 2; + break; + case 14: + ad7949_adc->buffer = ad7949_adc->cfg; + break; + case 8: + /* Pack 14-bit value into 2 bytes, MSB first */ + buf8[0] = FIELD_GET(GENMASK(13, 6), ad7949_adc->cfg); + buf8[1] = FIELD_GET(GENMASK(5, 0), ad7949_adc->cfg) << 2; + memcpy(&ad7949_adc->buffer, buf8, 2); + break; + default: + dev_err(&ad7949_adc->indio_dev->dev, "unsupported BPW\n"); + return -EINVAL; + } + spi_message_init_with_transfers(&msg, tx, 1); ret = spi_sync(ad7949_adc->spi, &msg); @@ -115,14 +136,13 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, { int ret; int i; - int bits_per_word = ad7949_adc->resolution; - int mask = GENMASK(ad7949_adc->resolution - 1, 0); + u8 buf8[2]; struct spi_message msg; struct spi_transfer tx[] = { { .rx_buf = &ad7949_adc->buffer, .len = 2, - .bits_per_word = bits_per_word, + .bits_per_word = ad7949_adc->bits_per_word, }, }; @@ -157,7 +177,26 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, ad7949_adc->current_channel = channel; - *val = ad7949_adc->buffer & mask; + switch (ad7949_adc->bits_per_word) { + case 16: + *val = ad7949_adc->buffer; + /* Shift-out padding bits */ + *val >>= 16 - ad7949_adc->resolution; + break; + case 14: + *val = ad7949_adc->buffer & GENMASK(13, 0); + break; + case 8: + memcpy(buf8, &ad7949_adc->buffer, 2); + /* Convert byte array to u16, MSB first */ + *val = get_unaligned_be16(buf8); + /* Shift-out padding bits */ + *val >>= 16 - ad7949_adc->resolution; + break; + default: + dev_err(&ad7949_adc->indio_dev->dev, "unsupported BPW\n"); + return -EINVAL; + } return 0; } @@ -265,6 +304,7 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc) static int ad7949_spi_probe(struct spi_device *spi) { + u32 spi_ctrl_mask = spi->controller->bits_per_word_mask; struct device *dev = &spi->dev; const struct ad7949_adc_spec *spec; struct ad7949_adc_chip *ad7949_adc; @@ -291,6 +331,18 @@ static int ad7949_spi_probe(struct spi_device *spi) indio_dev->num_channels = spec->num_channels; ad7949_adc->resolution = spec->resolution; + /* Set SPI bits per word */ + if (spi_ctrl_mask & SPI_BPW_MASK(ad7949_adc->resolution)) { + ad7949_adc->bits_per_word = ad7949_adc->resolution; + } else if (spi_ctrl_mask == SPI_BPW_MASK(16)) { + ad7949_adc->bits_per_word = 16; + } else if (spi_ctrl_mask == SPI_BPW_MASK(8)) { + ad7949_adc->bits_per_word = 8; + } else { + dev_err(dev, "unable to find common BPW with spi controller\n"); + return -EINVAL; + } + ad7949_adc->vref = devm_regulator_get(dev, "vref"); if (IS_ERR(ad7949_adc->vref)) { dev_err(dev, "fail to request regulator\n");