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=-15.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 E2C7FC636CA for ; Sat, 17 Jul 2021 17:32:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C763F61151 for ; Sat, 17 Jul 2021 17:32:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233355AbhGQRfQ (ORCPT ); Sat, 17 Jul 2021 13:35:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:33800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233128AbhGQRfN (ORCPT ); Sat, 17 Jul 2021 13:35:13 -0400 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (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 15DF860FE9; Sat, 17 Jul 2021 17:32:13 +0000 (UTC) Date: Sat, 17 Jul 2021 18:34:37 +0100 From: Jonathan Cameron To: Liam Beguin Cc: lars@metafoo.de, Michael.Hennerich@analog.com, charles-antoine.couret@essensium.com, Nuno.Sa@analog.com, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org Subject: Re: [PATCH v3 3/4] iio: adc: ad7949: add support for internal vref Message-ID: <20210717183437.4d183037@jic23-huawei> In-Reply-To: <20210713043425.3321230-4-liambeguin@gmail.com> References: <20210713043425.3321230-1-liambeguin@gmail.com> <20210713043425.3321230-4-liambeguin@gmail.com> X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 Jul 2021 00:34:24 -0400 Liam Beguin wrote: > From: Liam Beguin > > Add support for selecting a custom reference voltage from the > devicetree. If an external source is used, a vref regulator should be > defined in the devicetree. > > Signed-off-by: Liam Beguin Hi Liam, A few minor things inline. Jonathan > --- > drivers/iio/adc/ad7949.c | 133 +++++++++++++++++++++++++++++++++------ > 1 file changed, 115 insertions(+), 18 deletions(-) > > diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c > index 65f78751225b..8b78da7ead36 100644 > --- a/drivers/iio/adc/ad7949.c > +++ b/drivers/iio/adc/ad7949.c > @@ -36,7 +36,11 @@ > > /* REF: reference/buffer selection */ > #define AD7949_CFG_BIT_REF GENMASK(5, 3) > -#define AD7949_CFG_VAL_REF_EXT_BUF 7 > +#define AD7949_CFG_VAL_REF_EXT_TEMP_BUF 3 > +#define AD7949_CFG_VAL_REF_EXT_TEMP 2 > +#define AD7949_CFG_VAL_REF_INT_4096 1 > +#define AD7949_CFG_VAL_REF_INT_2500 0 > +#define AD7949_CFG_VAL_REF_EXTERNAL BIT(1) > > /* SEQ: channel sequencer. Allows for scanning channels */ > #define AD7949_CFG_BIT_SEQ GENMASK(2, 1) > @@ -61,6 +65,14 @@ static const struct ad7949_adc_spec ad7949_adc_spec[] = { > [ID_AD7689] = { .num_channels = 8, .resolution = 16 }, > }; > > +/** > + * struct ad7949_channel - ADC Channel parameters > + * @refsel: reference selection > + */ > +struct ad7949_channel { > + u32 refsel; > +}; > + > /** > * struct ad7949_adc_chip - AD ADC chip > * @lock: protects write sequences > @@ -78,6 +90,7 @@ struct ad7949_adc_chip { > struct regulator *vref; > struct iio_dev *indio_dev; > struct spi_device *spi; > + struct ad7949_channel *channels; > u8 resolution; > u8 bits_per_word; > u16 cfg; > @@ -138,6 +151,7 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, > int i; > u8 buf8[2]; > struct spi_message msg; > + struct ad7949_channel ad7949_chan = ad7949_adc->channels[channel]; Better to use a pointer rather than copying the data. > struct spi_transfer tx[] = { > { > .rx_buf = &ad7949_adc->buffer, > @@ -154,8 +168,9 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val, > */ > for (i = 0; i < 2; i++) { > ret = ad7949_spi_write_cfg(ad7949_adc, > - FIELD_PREP(AD7949_CFG_BIT_INX, channel), > - AD7949_CFG_BIT_INX); > + FIELD_PREP(AD7949_CFG_BIT_INX, channel) | > + FIELD_PREP(AD7949_CFG_BIT_REF, ad7949_chan.refsel), > + AD7949_CFG_BIT_INX | AD7949_CFG_BIT_REF); > if (ret) > return ret; > if (channel == ad7949_adc->current_channel) > @@ -225,6 +240,7 @@ static int ad7949_spi_read_raw(struct iio_dev *indio_dev, > int *val, int *val2, long mask) > { > struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev); > + struct ad7949_channel ad7949_chan = ad7949_adc->channels[chan->channel]; > int ret; > > if (!val) > @@ -242,12 +258,26 @@ static int ad7949_spi_read_raw(struct iio_dev *indio_dev, > return IIO_VAL_INT; > > case IIO_CHAN_INFO_SCALE: > - ret = regulator_get_voltage(ad7949_adc->vref); > - if (ret < 0) > - return ret; > + switch (ad7949_chan.refsel) { > + case AD7949_CFG_VAL_REF_INT_2500: > + *val = 2500; > + break; > + case AD7949_CFG_VAL_REF_INT_4096: > + *val = 4096; > + break; > + case AD7949_CFG_VAL_REF_EXT_TEMP: > + case AD7949_CFG_VAL_REF_EXT_TEMP_BUF: > + ret = regulator_get_voltage(ad7949_adc->vref); > + if (ret < 0) > + return ret; > + > + /* convert value back to mV */ > + *val = ret / 1000; > + break; > + } > > - *val = ret / 5000; > - return IIO_VAL_INT; > + *val2 = (1 << ad7949_adc->resolution) - 1; > + return IIO_VAL_FRACTIONAL; > } > > return -EINVAL; > @@ -286,7 +316,7 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc) > FIELD_PREP(AD7949_CFG_BIT_INCC, AD7949_CFG_VAL_INCC_UNIPOLAR_GND) | > FIELD_PREP(AD7949_CFG_BIT_INX, ad7949_adc->current_channel) | > FIELD_PREP(AD7949_CFG_BIT_BW_FULL, 1) | > - FIELD_PREP(AD7949_CFG_BIT_REF, AD7949_CFG_VAL_REF_EXT_BUF) | > + FIELD_PREP(AD7949_CFG_BIT_REF, ad7949_adc->channels[0].refsel) | > FIELD_PREP(AD7949_CFG_BIT_SEQ, 0x0) | > FIELD_PREP(AD7949_CFG_BIT_RBN, 1); > > @@ -302,14 +332,24 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc) > return ret; > } > > +static void ad7949_disable_reg(void *reg) > +{ > + regulator_disable(reg); > +} > + > 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; > + struct ad7949_channel *ad7949_chan; > + struct device_node *child; > struct iio_dev *indio_dev; > + int mode; > + u32 tmp; > int ret; > + int i; > > indio_dev = devm_iio_device_alloc(dev, sizeof(*ad7949_adc)); > if (!indio_dev) { > @@ -343,16 +383,75 @@ static int ad7949_spi_probe(struct spi_device *spi) > return -EINVAL; > } > > - ad7949_adc->vref = devm_regulator_get(dev, "vref"); > + /* Setup external voltage ref, buffered? */ > + ad7949_adc->vref = devm_regulator_get(dev, "vrefin"); > if (IS_ERR(ad7949_adc->vref)) { > - dev_err(dev, "fail to request regulator\n"); > - return PTR_ERR(ad7949_adc->vref); > + /* unbuffered? */ > + ad7949_adc->vref = devm_regulator_get(dev, "vref"); > + if (IS_ERR(ad7949_adc->vref)) { > + /* Internal then */ > + mode = AD7949_CFG_VAL_REF_INT_4096; > + } > + mode = AD7949_CFG_VAL_REF_EXT_TEMP; > } > + mode = AD7949_CFG_VAL_REF_EXT_TEMP_BUF; > > - ret = regulator_enable(ad7949_adc->vref); > - if (ret < 0) { > - dev_err(dev, "fail to enable regulator\n"); > - return ret; > + if (mode > AD7949_CFG_VAL_REF_INT_4096) { Range checks on enum values are always rather messy. So better to explicitly match the cases that matter. > + ret = regulator_enable(ad7949_adc->vref); > + if (ret < 0) { > + dev_err(dev, "fail to enable regulator\n"); > + return ret; > + } > + > + ret = devm_add_action_or_reset(dev, ad7949_disable_reg, > + ad7949_adc->vref); > + if (ret) > + return ret; > + } > + > + ad7949_adc->channels = devm_kcalloc(dev, spec->num_channels, > + sizeof(*ad7949_adc->channels), > + GFP_KERNEL); > + if (!ad7949_adc->channels) { > + dev_err(dev, "unable to allocate ADC channels\n"); > + return -ENOMEM; > + } > + > + /* Initialize all channel structures */ > + for (i = 0; i < spec->num_channels; i++) { > + ad7949_adc->channels[i].refsel = mode; Kernel style is no brackets when only one item in a block. > + } > + > + /* Read channel specific information form the devicetree */ > + for_each_child_of_node(dev->of_node, child) { > + ret = of_property_read_u32(child, "reg", &i); > + if (ret) { > + dev_err(dev, "missing reg property in child: %s\n", > + child->full_name); > + of_node_put(child); > + return ret; > + } > + > + ad7949_chan = &ad7949_adc->channels[i]; > + > + ret = of_property_read_u32(child, "adi,internal-ref-mv", &tmp); Preference for generic device firmware properties not of_* specific ones. I think there is nothing stopping this driver being probed from ACPI via PRP0001 before this change. Note you'll also need fwnode_for_each_child_node() above. > + if (ret < 0 && ret != -EINVAL) { > + of_node_put(child); > + return ret; > + } > + > + switch (tmp) { > + case 2500: > + ad7949_chan->refsel = AD7949_CFG_VAL_REF_INT_2500; > + break; > + case 4096: > + ad7949_chan->refsel = AD7949_CFG_VAL_REF_INT_4096; > + break; > + default: > + dev_err(dev, "unsupported internal voltage reference\n"); > + of_node_put(child); > + return -EINVAL; > + } > } > > mutex_init(&ad7949_adc->lock); > @@ -373,7 +472,6 @@ static int ad7949_spi_probe(struct spi_device *spi) > > err: > mutex_destroy(&ad7949_adc->lock); > - regulator_disable(ad7949_adc->vref); > > return ret; > } > @@ -385,7 +483,6 @@ static int ad7949_spi_remove(struct spi_device *spi) > > iio_device_unregister(indio_dev); > mutex_destroy(&ad7949_adc->lock); > - regulator_disable(ad7949_adc->vref); Given mutex_destroy is mostly pointless (and definitely is here) that leaves us with just iio_device_register(). Hence if you could do a follow up patch finishing conversion of this to entirely devm managed that would be a nice addition to this series (or separate patch is fine as well). > > return 0; > }