From patchwork Fri Mar 31 12:32:38 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabrice Gasnier X-Patchwork-Id: 9656219 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5614360351 for ; Fri, 31 Mar 2017 12:34:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4679228646 for ; Fri, 31 Mar 2017 12:34:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3B1A528689; Fri, 31 Mar 2017 12:34:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D25A228646 for ; Fri, 31 Mar 2017 12:34:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=u/h1a6deN21YIUPheIeJ2UGUYBHrX3sxiaViqqNAmsA=; b=VOmMkEJ0KLaus5 AJManCyzzMGEn/R+YcMKBQdDdTYEZTLPNr1Hu6P1NxT/TQskBdPegpeteSs8dtcMA8L/RiH+Gxvr2 fWpFIOwU0xTUzvGavsqnEKq+WjIe7c036ktvWu8RAzk1mv8O9jp7uCGUyvUU5mC4MTu8kT6/RlD2w 1u/7oP8L4x0tKrfterEI8Edw6kI5cGviqcHGy4UtRfgDeSb4tohi8pEZ4xfIsVhS35x5683BUY8Ef lPA+pfHYX8nZxWm6Vdxx9DL4iVrLDeygrbXCkfMi4qxUKN5+T4H49zaldqub4+kq93e5C4DWilR7b WzqvT+t1y5w2hH8CeA2A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1ctvl1-0006h4-6v; Fri, 31 Mar 2017 12:34:23 +0000 Received: from mx07-00178001.pphosted.com ([62.209.51.94]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1ctvkC-0005Ub-2I for linux-arm-kernel@lists.infradead.org; Fri, 31 Mar 2017 12:33:36 +0000 Received: from pps.filterd (m0046037.ppops.net [127.0.0.1]) by m0046037.ppops.net (8.16.0.11/8.16.0.11) with SMTP id v2VCSpcv032526; Fri, 31 Mar 2017 14:32:57 +0200 Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-.pphosted.com with ESMTP id 29h2kaphwu-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Fri, 31 Mar 2017 14:32:57 +0200 Received: from zeta.dmz-eu.st.com (zeta.dmz-eu.st.com [164.129.230.9]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 50CA434; Fri, 31 Mar 2017 12:32:57 +0000 (GMT) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by zeta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 10B022971; Fri, 31 Mar 2017 12:32:57 +0000 (GMT) Received: from localhost (10.75.127.49) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1178.4; Fri, 31 Mar 2017 14:32:56 +0200 From: Fabrice Gasnier To: , , , , , Subject: [PATCH v2 2/2] iio: adc: stm32: add dt option to set resolution Date: Fri, 31 Mar 2017 14:32:38 +0200 Message-ID: <1490963559-32159-3-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1490963559-32159-1-git-send-email-fabrice.gasnier@st.com> References: <1490963559-32159-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.49] X-ClientProxiedBy: SFHDAG4NODE1.st.com (10.75.127.10) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-03-31_11:, , signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170331_053332_532856_2A8F248A X-CRM114-Status: GOOD ( 14.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, benjamin.gaignard@linaro.org, lars@metafoo.de, alexandre.torgue@st.com, linux-iio@vger.kernel.org, pmeerw@pmeerw.net, mcoquelin.stm32@gmail.com, knaack.h@gmx.de, fabrice.gasnier@st.com, linus.walleij@linaro.org, benjamin.gaignard@st.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP stm32 adc supports several resolution. Add 'assigned-resolution-bits' dt optional property to set it. Default to maximum resolution in case it isn't set. Signed-off-by: Fabrice Gasnier --- Changes in v2: - rename property from 'st,adc-res' to 'assigned-resolution-bits', so it is more common. --- drivers/iio/adc/stm32-adc.c | 50 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index 9b49a6ad..c28e7ff 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -60,6 +60,8 @@ #define STM32F4_EOC BIT(1) /* STM32F4_ADC_CR1 - bit fields */ +#define STM32F4_RES_SHIFT 24 +#define STM32F4_RES_MASK GENMASK(25, 24) #define STM32F4_SCAN BIT(8) #define STM32F4_EOCIE BIT(5) @@ -141,6 +143,7 @@ struct stm32_adc_regs { * @lock: spinlock * @bufi: data buffer index * @num_conv: expected number of scan conversions + * @res: data resolution (e.g. RES bitfield value) * @trigger_polarity: external trigger polarity (e.g. exten) * @dma_chan: dma channel * @rx_buf: dma rx buffer cpu address @@ -157,6 +160,7 @@ struct stm32_adc { spinlock_t lock; /* interrupt lock */ unsigned int bufi; unsigned int num_conv; + u32 res; u32 trigger_polarity; struct dma_chan *dma_chan; u8 *rx_buf; @@ -196,6 +200,11 @@ struct stm32_adc_chan_spec { { IIO_VOLTAGE, 15, "in15" }, }; +static const unsigned int stm32f4_adc_resolutions[] = { + /* sorted values so the index matches RES[1:0] in STM32F4_ADC_CR1 */ + 12, 10, 8, 6, +}; + /** * stm32f4_sq - describe regular sequence registers * - L: sequence len (register & bit field) @@ -302,6 +311,14 @@ static void stm32_adc_conv_irq_disable(struct stm32_adc *adc) stm32_adc_clr_bits(adc, STM32F4_ADC_CR1, STM32F4_EOCIE); } +static void stm32_adc_set_res(struct stm32_adc *adc) +{ + u32 val = stm32_adc_readl(adc, STM32F4_ADC_CR1); + + val = (val & ~STM32F4_RES_MASK) | (adc->res << STM32F4_RES_SHIFT); + stm32_adc_writel(adc, STM32F4_ADC_CR1, val); +} + /** * stm32_adc_start_conv() - Start conversions for regular channels. * @adc: stm32 adc instance @@ -870,11 +887,37 @@ static irqreturn_t stm32_adc_trigger_handler(int irq, void *p) {}, }; +static int stm32_adc_of_get_resolution(struct iio_dev *indio_dev) +{ + struct device_node *node = indio_dev->dev.of_node; + struct stm32_adc *adc = iio_priv(indio_dev); + unsigned int i; + u32 res; + + if (of_property_read_u32(node, "assigned-resolution-bits", &res)) + res = stm32f4_adc_resolutions[0]; + + for (i = 0; i < ARRAY_SIZE(stm32f4_adc_resolutions); i++) + if (res == stm32f4_adc_resolutions[i]) + break; + if (i >= ARRAY_SIZE(stm32f4_adc_resolutions)) { + dev_err(&indio_dev->dev, "Bad resolution: %u bits\n", res); + return -EINVAL; + } + + dev_dbg(&indio_dev->dev, "Using %u bits resolution\n", res); + adc->res = i; + + return 0; +} + static void stm32_adc_chan_init_one(struct iio_dev *indio_dev, struct iio_chan_spec *chan, const struct stm32_adc_chan_spec *channel, int scan_index) { + struct stm32_adc *adc = iio_priv(indio_dev); + chan->type = channel->type; chan->channel = channel->channel; chan->datasheet_name = channel->name; @@ -883,7 +926,7 @@ static void stm32_adc_chan_init_one(struct iio_dev *indio_dev, chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE); chan->scan_type.sign = 'u'; - chan->scan_type.realbits = 12; + chan->scan_type.realbits = stm32f4_adc_resolutions[adc->res]; chan->scan_type.storagebits = 16; chan->ext_info = stm32_adc_ext_info; } @@ -1022,6 +1065,11 @@ static int stm32_adc_probe(struct platform_device *pdev) return ret; } + ret = stm32_adc_of_get_resolution(indio_dev); + if (ret < 0) + goto err_clk_disable; + stm32_adc_set_res(adc); + ret = stm32_adc_chan_of_init(indio_dev); if (ret < 0) goto err_clk_disable;