From patchwork Fri Jul 9 15:58:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liam Beguin X-Patchwork-Id: 12367637 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=-16.0 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=unavailable 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 44AACC11F68 for ; Fri, 9 Jul 2021 15:59:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31AC8613C9 for ; Fri, 9 Jul 2021 15:59:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231976AbhGIQB6 (ORCPT ); Fri, 9 Jul 2021 12:01:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232422AbhGIQBy (ORCPT ); Fri, 9 Jul 2021 12:01:54 -0400 Received: from mail-qk1-x72c.google.com (mail-qk1-x72c.google.com [IPv6:2607:f8b0:4864:20::72c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68894C0613DD; Fri, 9 Jul 2021 08:59:10 -0700 (PDT) Received: by mail-qk1-x72c.google.com with SMTP id s4so9725076qkm.13; Fri, 09 Jul 2021 08:59:10 -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=WVzaufTKjI7vFE0WAp9ETvQcf722VGc26MQp2yQzB7M=; b=QNblqPWByV8M/v0AKo0T6pJJ59EF6N8LN0xEUrMT7ahzm2W0M0bZtRtpC5JbyjnURT rJMPAvUJMc4lnsYVm5TranAhS3DN06zE9QBqLlkVRb65gDOj1RmwM91jLlvYeDUMmXlr UUmFje7vi+GyrOx38qu+VivsBDrLtOMqaIkNmWYZa9ZhKaCwG0xRw80mkeWs2SLYRSCl u2sZW6rmaUy2OVDoLncDYdyqoM+/p9zkmIrIhGN08d12GZSAsWgMQ/oc0UBCH2BF+ADM 5RuPd47lr4dZXA0sqV/r3v0jfWGj8WVjiVfHvKIkCbV9/EypDxcfV+0v5mMftZvabDTD zhUw== 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=WVzaufTKjI7vFE0WAp9ETvQcf722VGc26MQp2yQzB7M=; b=h19+m9fKaQyRtiDC29/ANZBwX5KJ82lnGXYseRQU7q5yk1ZchSdA4FIO4IIgO5kzfD 1yih+0Mq5y2TSOa369OekIJrzinm8txfkUaH+FGCzoQxSC6n56cAveOlfL881fRInVSD ZkyQ7V+NfGu9L/r8ZARnDCfTIKplHHl6KhTCfIZ1LiS7wJCDSiiYz025iML4WixlTpd0 PTq2jAw8LsQEsp2gVA82SgY83vI5h+Blc3USUa603gQ0R6xQcUxYwX3Ouf87+SqR3Uv4 /VD9/FPYPVYpHTEK34sqeP1D3QE60eAv0o7MAO9/umMAueJICv0cMl6CzBViLr5c1O7F /jjA== X-Gm-Message-State: AOAM532SxAmhusFfSePL3BDdtQkKZAaftyftsYVQCAe6MOAX6e6S+eyN a0G2uRE6qA6KuWqzeIz57wk= X-Google-Smtp-Source: ABdhPJxIHLKuMZ4Jq1bbpghyvw/CUGGsf7U6/boIIOdiKSwRr3hN1U1JYfWcBhtjuEBm2EJ+ABTLSA== X-Received: by 2002:a05:620a:e09:: with SMTP id y9mr37864332qkm.359.1625846349604; Fri, 09 Jul 2021 08:59:09 -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 x15sm2606071qkm.66.2021.07.09.08.59.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Jul 2021 08:59:09 -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 v2 2/4] iio: adc: ad7949: fix spi messages on non 14-bit controllers Date: Fri, 9 Jul 2021 11:58:54 -0400 Message-Id: <20210709155856.1732245-3-liambeguin@gmail.com> X-Mailer: git-send-email 2.30.1.489.g328c10930387 In-Reply-To: <20210709155856.1732245-1-liambeguin@gmail.com> References: <20210709155856.1732245-1-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 | 69 ++++++++++++++++++++++++++++++++++------ 1 file changed, 60 insertions(+), 9 deletions(-) diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c index 93aacf4f680b..770112ac820f 100644 --- a/drivers/iio/adc/ad7949.c +++ b/drivers/iio/adc/ad7949.c @@ -11,6 +11,7 @@ #include #include #include +#include #define AD7949_MASK_TOTAL GENMASK(13, 0) #define AD7949_CFG_REG_SIZE_BITS 14 @@ -57,6 +58,7 @@ 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 @@ -67,28 +69,60 @@ 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; + union { + __be16 buffer; + u8 buf8[2]; + } ____cacheline_aligned; }; +static void ad7949_set_bits_per_word(struct ad7949_adc_chip *ad7949_adc) +{ + u32 adc_mask = SPI_BPW_MASK(ad7949_adc->resolution); + u32 bpw = adc_mask & ad7949_adc->spi->controller->bits_per_word_mask; + + if (bpw == adc_mask) + ad7949_adc->bits_per_word = ad7949_adc->resolution; + else if (bpw == SPI_BPW_MASK(16)) + ad7949_adc->bits_per_word = 16; + else + ad7949_adc->bits_per_word = 8; +} + 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; 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: + default: + /* Pack 14-bit value into 2 bytes, MSB first */ + ad7949_adc->buf8[0] = FIELD_GET(GENMASK(13, 6), ad7949_adc->cfg); + ad7949_adc->buf8[1] = FIELD_GET(GENMASK(5, 0), ad7949_adc->cfg); + ad7949_adc->buf8[1] = ad7949_adc->buf8[1] << 2; + break; + } + spi_message_init_with_transfers(&msg, tx, 1); ret = spi_sync(ad7949_adc->spi, &msg); @@ -105,14 +139,12 @@ 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); 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, }, }; @@ -147,7 +179,25 @@ 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 */ + if (ad7949_adc->resolution == 14) + *val = *val >> 2; + break; + case 14: + *val = ad7949_adc->buffer & GENMASK(13, 0); + break; + case 8: + default: + /* Convert byte array to u16, MSB first */ + *val = (ad7949_adc->buf8[0] << 8) | ad7949_adc->buf8[1]; + /* Shift-out padding bits */ + if (ad7949_adc->resolution == 14) + *val = *val >> 2; + break; + } return 0; } @@ -280,6 +330,7 @@ static int ad7949_spi_probe(struct spi_device *spi) spec = &ad7949_adc_spec[spi_get_device_id(spi)->driver_data]; indio_dev->num_channels = spec->num_channels; ad7949_adc->resolution = spec->resolution; + ad7949_set_bits_per_word(ad7949_adc); ad7949_adc->vref = devm_regulator_get(dev, "vref"); if (IS_ERR(ad7949_adc->vref)) {