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[198.48.202.89]) by smtp.gmail.com with ESMTPSA id i67sm1635515qkd.90.2021.08.13.13.51.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Aug 2021 13:51:14 -0700 (PDT) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Fri, 13 Aug 2021 16:51:12 -0400 Message-Id: Cc: , , , , , , , Subject: Re: [PATCH v5 3/5] iio: adc: ad7949: add support for internal vref From: "Liam Beguin" To: "Jonathan Cameron" References: <20210808015659.2955443-1-liambeguin@gmail.com> <20210808015659.2955443-4-liambeguin@gmail.com> <20210808173630.5c384a4b@jic23-huawei> <20210809204253.357f97b2@jic23-huawei> In-Reply-To: <20210809204253.357f97b2@jic23-huawei> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Mon Aug 9, 2021 at 3:42 PM EDT, Jonathan Cameron wrote: > ... > > + > > > > static int ad7949_spi_probe(struct spi_device *spi) > > > > { > > > > u32 spi_ctrl_mask =3D spi->controller->bits_per_word_mask; > > > > struct device *dev =3D &spi->dev; > > > > const struct ad7949_adc_spec *spec; > > > > struct ad7949_adc_chip *ad7949_adc; > > > > + struct ad7949_channel *ad7949_chan; > > > > + struct fwnode_handle *child; > > > > struct iio_dev *indio_dev; > > > > + int mode; > > > > + u32 tmp; > > > > int ret; > > > > + int i; > > > > =20 > > > > indio_dev =3D devm_iio_device_alloc(dev, sizeof(*ad7949_adc)); > > > > if (!indio_dev) { > > > > @@ -343,16 +383,82 @@ static int ad7949_spi_probe(struct spi_device= *spi) > > > > return -EINVAL; > > > > } > > > > =20 > > > > - ad7949_adc->vref =3D devm_regulator_get(dev, "vref"); > > > > + /* Setup external voltage ref, buffered? */ > > > > + ad7949_adc->vref =3D devm_regulator_get_optional(dev, "vrefin"); > > > > if (IS_ERR(ad7949_adc->vref)) { > > > > - dev_err(dev, "fail to request regulator\n"); > > > > - return PTR_ERR(ad7949_adc->vref); > > > > + ret =3D PTR_ERR(ad7949_adc->vref); > > > > + if (ret !=3D -ENODEV) > > > > + return ret; > > > > + /* unbuffered? */ > > > > + ad7949_adc->vref =3D devm_regulator_get_optional(dev, "vref"); > > > > + if (IS_ERR(ad7949_adc->vref)) { > > > > + ret =3D PTR_ERR(ad7949_adc->vref); > > > > + if (ret !=3D -ENODEV) > > > > + return ret; > > > > + /* Internal then */ > > > > + mode =3D AD7949_CFG_VAL_REF_INT_4096; > > > > + } else { > > > > + mode =3D AD7949_CFG_VAL_REF_EXT_TEMP; > > > > + } > > > > + } else { > > > > + mode =3D AD7949_CFG_VAL_REF_EXT_TEMP_BUF; > > > > } > > > > =20 > > > > - ret =3D regulator_enable(ad7949_adc->vref); > > > > - if (ret < 0) { > > > > - dev_err(dev, "fail to enable regulator\n"); > > > > - return ret; > > > > + if (mode & AD7949_CFG_VAL_REF_EXTERNAL) { > > > > + ret =3D regulator_enable(ad7949_adc->vref); > > > > + if (ret < 0) { > > > > + dev_err(dev, "fail to enable regulator\n"); > > > > + return ret; > > > > + } > > > > + > > > > + ret =3D devm_add_action_or_reset(dev, ad7949_disable_reg, > > > > + ad7949_adc->vref); > > > > + if (ret) > > > > + return ret; > > > > + } > > > > + > > > > + ad7949_adc->channels =3D 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 =3D 0; i < spec->num_channels; i++) > > > > + ad7949_adc->channels[i].refsel =3D mode; > > > > + > > > > + /* Read channel specific information form the devicetree */ > > > > + device_for_each_child_node(dev, child) { > > > > + ret =3D fwnode_property_read_u32(child, "reg", &i); > > > > + if (ret) { > > > > + dev_err(dev, "missing reg property in %pfw\n", child); > > > > + fwnode_handle_put(child); > > > > + return ret; > > > > + } > > > > + > > > > + ad7949_chan =3D &ad7949_adc->channels[i]; > > > > + > > > > + ret =3D fwnode_property_read_u32(child, "adi,internal-ref-microv= olt", &tmp); > > > > + if (ret < 0 && ret !=3D -EINVAL) { > > > > + dev_err(dev, "invalid internal reference in %pfw\n", child); > > > > + fwnode_handle_put(child); > > > > + return ret; > > > > + } =20 > >=20 > > Hi Jonathan, > >=20 > > > > > > So if we are using external voltage, then we'd not expect this to exi= st. > > > ret !=3D -EINVAL should deal with that. However, we then hit the foll= owing > > > switch > > > and temp isn't set to an appropriate value so we get the error. > > > > > > Am I missing something? =20 > >=20 > > You're right that using an external reference, will cause this to fail. > > My apologies, I've done a poor job of testing the last two revisions of > > this patch. I'll do better. > >=20 > > Since a regulator is also required when we're using an external source, > > I'll add a check for that. Something like this: > >=20 > > ret =3D fwnode_property_read_u32(child, "adi,internal-ref-microvolt", = &tmp); > > if (ret =3D=3D -EINVAL && mode & AD7949_CFG_VAL_REF_EXTERNAL) { > > continue; > > } else if (ret < 0) { > > dev_err(dev, "invalid voltage reference in %pfw\n", child); > > fwnode_handle_put(child); > > return ret; > > } > > Makes sense. Hi Jonathan, After getting access to another setup to run more tests, I noticed that setting the reference per channel isn't really feasible. It take a little while for the reference to be updated internally even though the request is sent out properly, and reading channels in a sequence returns bad values. I'll resend this without the per-channel configuration and make adi,internal-ref-microvolt a global parameter. Sorry about that, Liam > > >=20 > > Given that we can now have a different scale for each channel based on > > the vref source, should BIT(IIO_CHAN_INFO_SCALE) be moved to > > .info_mask_separate in the channel definition? > Yes, good point. > > Hopefully no one will notice the ABI change *crosses fingers*. > > Jonathan > > >=20 > > Thanks, > > Liam > >=20 > > > =20 > > > > + > > > > + switch (tmp) { > > > > + case 2500000: > > > > + ad7949_chan->refsel =3D AD7949_CFG_VAL_REF_INT_2500; > > > > + break; > > > > + case 4096000: > > > > + ad7949_chan->refsel =3D AD7949_CFG_VAL_REF_INT_4096; > > > > + break; > > > > + default: > > > > + dev_err(dev, "unsupported internal voltage reference\n"); > > > > + fwnode_handle_put(child); > > > > + return -EINVAL; > > > > + } > > > > } > > > > =20 > > > > mutex_init(&ad7949_adc->lock); > > > > @@ -373,7 +479,6 @@ static int ad7949_spi_probe(struct spi_device *= spi) > > > > =20 > > > > err: > > > > mutex_destroy(&ad7949_adc->lock); > > > > - regulator_disable(ad7949_adc->vref); > > > > =20 > > > > return ret; > > > > } > > > > @@ -385,7 +490,6 @@ static int ad7949_spi_remove(struct spi_device = *spi) > > > > =20 > > > > iio_device_unregister(indio_dev); > > > > mutex_destroy(&ad7949_adc->lock); > > > > - regulator_disable(ad7949_adc->vref); > > > > =20 > > > > return 0; > > > > } =20 > >=20