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Fri, 14 Mar 2025 13:19:35 -0400 Received: from ASHBMBX8.ad.analog.com (10.64.17.5) by ASHBMBX9.ad.analog.com (10.64.17.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.14; Fri, 14 Mar 2025 13:19:35 -0400 Received: from zeus.spd.analog.com (10.66.68.11) by ashbmbx8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server id 15.2.986.14 via Frontend Transport; Fri, 14 Mar 2025 13:19:35 -0400 Received: from work.ad.analog.com (HYB-hERzalRezfV.ad.analog.com [10.65.205.9]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 52EHJKjQ005021; Fri, 14 Mar 2025 13:19:23 -0400 From: Marcelo Schmitt To: , , CC: , , , , Subject: [PATCH v1 3/4] Documentation: iio: ad4000: Add IIO Device characteristics section Date: Fri, 14 Mar 2025 14:19:17 -0300 Message-ID: <5cc6522c55f7e1ac2713e769690748c66813a995.1741970538.git.marcelo.schmitt@analog.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-GUID: ZfhIIM1o-yk6zDazNfPV3IYkikftm0n3 X-Proofpoint-ORIG-GUID: ZfhIIM1o-yk6zDazNfPV3IYkikftm0n3 X-Authority-Analysis: v=2.4 cv=EL0G00ZC c=1 sm=1 tr=0 ts=67d46528 cx=c_pps a=PpDZqlmH/M8setHirZLBMw==:117 a=PpDZqlmH/M8setHirZLBMw==:17 a=Vs1iUdzkB0EA:10 a=gAnH3GRIAAAA:8 a=Mo4bjoQrprX0_McyEsMA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-14_06,2025-03-14_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 priorityscore=1501 impostorscore=0 phishscore=0 mlxlogscore=999 adultscore=0 spamscore=0 clxscore=1015 mlxscore=0 lowpriorityscore=0 malwarescore=0 suspectscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2502280000 definitions=main-2503140136 Complement ad4000 IIO driver documentation with considerations about ``_scale_available`` attribute and table of typical channel attributes. Signed-off-by: Marcelo Schmitt --- Documentation/iio/ad4000.rst | 47 ++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/Documentation/iio/ad4000.rst b/Documentation/iio/ad4000.rst index 5578a9cfd9d5..468d30dc9214 100644 --- a/Documentation/iio/ad4000.rst +++ b/Documentation/iio/ad4000.rst @@ -144,3 +144,50 @@ Set ``adi,sdi-pin`` to ``"cs"`` to select this mode. ^ | | +--------------------| SCLK | +-------------+ + +IIO Device characteristics +========================== + +The AD4000 series driver supports differential and pseudo-differential ADCs. + +The span compression feature available in AD4000 series devices can be +enabled/disabled by changing the ``_scale_available`` attribute of the voltage +channel. Note that span compression configuration requires writing to AD4000 +configuration register, which is only possible when the ADC is wired in 3-wire +turbo mode, and the SPI controller is ``SPI_MOSI_IDLE_HIGH`` capable. If those +conditions are not met, no ``_scale_available`` attribute is provided. + +Besides that, differential and pseudo-differential voltage channels present +slightly different sysfs interfaces. + +Pseudo-differential ADCs +------------------------ + +Typical voltage channel attributes of a pseudo-differential AD4000 series device: + ++-------------------------------------------+------------------------------------------+ +| Voltage Channel Attributes | Description | ++===========================================+==========================================+ +| ``in_voltage0_raw`` | Raw ADC output code. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_offset`` | Offset to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_scale`` | Scale factor to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_scale_available`` | Toggles input span compression | ++-------------------------------------------+------------------------------------------+ + +Differential ADCs +----------------- + +Typical voltage channel attributes of a differential AD4000 series device: + ++-------------------------------------------+------------------------------------------+ +| Voltage Channel Attributes | Description | ++===========================================+==========================================+ +| ``in_voltage0-voltage1_raw`` | Raw ADC output code. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0-voltage1_scale`` | Scale factor to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0-voltage1_scale_available`` | Toggles input span compression | ++-------------------------------------------+------------------------------------------+