From patchwork Fri Nov 15 20:18:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Lechner X-Patchwork-Id: 13876794 Received: from mail-oa1-f45.google.com (mail-oa1-f45.google.com [209.85.160.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6C3251F8934 for ; Fri, 15 Nov 2024 20:19:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.45 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731701951; cv=none; b=gzcEuOEmLyD9012U4yn/xZLOeVbX1vSrkG4mWGL6uic+fIBzZfL2J6v3tRq6Ch+oZoZxpAv3+oZc2eJgrjewfdBSBQ697DoVHZO9BTyHsnicY1mRxuyNVqv/i8rqvQHmrCu/BOfP/lR27Dv2BOIktilIoyCSdOAXzeMPfZg0tL0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731701951; c=relaxed/simple; bh=K0ELSxsB5ewnDfByel6azG1qzhpSdfFUlrceHRoZqqY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gkqqk5YB0wP2XxKvQPqz4WhIorKyJHn3Ve3KlDZmujUrl7IPpb6gk+K1cw0Y4NYuBd3m2Qc79WhyCNfC9K54z4yFI91lPAq5togLLX9KicLKO/XeItkTnmk9i0gn6GbBTvwx0zuN9ems8d7/o7ff4UFQLdKeO3FN1oRNotdXmeA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=baylibre.com; spf=pass smtp.mailfrom=baylibre.com; dkim=pass (2048-bit key) header.d=baylibre-com.20230601.gappssmtp.com header.i=@baylibre-com.20230601.gappssmtp.com header.b=iLOt5OkK; arc=none smtp.client-ip=209.85.160.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=baylibre.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=baylibre.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=baylibre-com.20230601.gappssmtp.com header.i=@baylibre-com.20230601.gappssmtp.com header.b="iLOt5OkK" Received: by mail-oa1-f45.google.com with SMTP id 586e51a60fabf-28c7f207806so984296fac.3 for ; Fri, 15 Nov 2024 12:19:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20230601.gappssmtp.com; s=20230601; t=1731701948; x=1732306748; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=gHWSp9g71dav0wBB3RsBnAwDxMnAi0+sYhD4RSgE92s=; b=iLOt5OkKff+H5qnAg29jnxdMSADjMWv2Sf9Mj0EybfejW3UveERNNhVF1EfBKL/QqY /cWsP4VzVQq6+dc/jkUd/wrmWOD+riSMQ4COkYHemH4zcDe/fWa798zioVavY0Ed0TWa dQ6wx329dxa1F8jhbx7rIUPaZGyA4Cwps7+E/3CKkjRpKmcvgapykEieeMwjY08vAOPl u8l0HFef/L10UTUNRKfE/4hRlpd2S1HKumYvcVh1dPVdBfxvgU0+/SXJ08BiItKXr8LP 34CKDIcKbNdaHLLOnIz+Zgvk2ERupSs3ooqKJ1ucFJXCiNDvkXDYoiFOB/X4oRzDxqa4 iLqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731701948; x=1732306748; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=gHWSp9g71dav0wBB3RsBnAwDxMnAi0+sYhD4RSgE92s=; b=rOHDQh0kG6jsL+JVphvrkK9ldjPwbFBhCx9UwUPNXHmcadyflbpzhWjv9Og9l+3Dhe +5+pLXn8OEhANjE3nzRdkkwAj17TXqaSW7paPOBEeu1SS4eu+2u11RnXQC8PTvY952NR ZjN+3zsXJ96w4MZ1vDOecrmbmgaPf2dELIZmSW8cSn6xPKzmS9MFapgX5vNJEOrrXmML BuZbpxN16oFF8HniskSqWvDz5bClt2y41o2IWsiKjDhGs4RsWhN2g0SzWqsXLeoKQyjR O0ROECTlbTw2zp7lIN1ulPyLTv4sH1LHHJJmYJ1xc1dJAuRXzGs0fsBeY7pnI2w0QOt5 jvnw== X-Forwarded-Encrypted: i=1; AJvYcCXLvpy2GWwhJ/1MrBfinhoQZbNyfVTrub8ZLjJqBPy+eURMAli6WhEY2ZMvnPfX5Y7i2B3TgR6gIoo=@vger.kernel.org X-Gm-Message-State: AOJu0YyziDUsUocMU0omj8MTImM5iK+fESpAAEFgVju+zWkO9QmrFArS g5Q7mD97zYpga5lW8mBiuD9BhVf/FZ9UNVWy15hSL0C1GW1kD+KBk9g7qb/sCTc= X-Google-Smtp-Source: AGHT+IGWBHYcdZrBR+Etr+tBdm3Lz7gnqd+0QTKy8x+5SgSS97gRVwEjKew7vBfdhv9QAdngjnHbCA== X-Received: by 2002:a05:6870:32d4:b0:27c:df1d:85c6 with SMTP id 586e51a60fabf-2962dd3a1c0mr3912680fac.8.1731701948269; Fri, 15 Nov 2024 12:19:08 -0800 (PST) Received: from [127.0.1.1] (ip98-183-112-25.ok.ok.cox.net. [98.183.112.25]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-71a780ea62esm748978a34.5.2024.11.15.12.19.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Nov 2024 12:19:06 -0800 (PST) From: David Lechner Date: Fri, 15 Nov 2024 14:18:52 -0600 Subject: [PATCH v5 13/16] doc: iio: ad7944: describe offload support Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241115-dlech-mainline-spi-engine-offload-2-v5-13-bea815bd5ea5@baylibre.com> References: <20241115-dlech-mainline-spi-engine-offload-2-v5-0-bea815bd5ea5@baylibre.com> In-Reply-To: <20241115-dlech-mainline-spi-engine-offload-2-v5-0-bea815bd5ea5@baylibre.com> To: Mark Brown , Jonathan Cameron , Rob Herring , Krzysztof Kozlowski , Conor Dooley , =?utf-8?q?Nuno_S=C3=A1?= Cc: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= , Michael Hennerich , Lars-Peter Clausen , David Jander , Martin Sperl , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, linux-pwm@vger.kernel.org, David Lechner X-Mailer: b4 0.14.1 Add a section to the ad7944 documentation describing how to use the driver with SPI offloading. Signed-off-by: David Lechner --- v5 changes: new patch in v5 --- Documentation/iio/ad7944.rst | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/Documentation/iio/ad7944.rst b/Documentation/iio/ad7944.rst index 0d26e56aba88..e6dbe4d7f58c 100644 --- a/Documentation/iio/ad7944.rst +++ b/Documentation/iio/ad7944.rst @@ -46,6 +46,8 @@ CS mode, 3-wire, without busy indicator To select this mode in the device tree, set the ``adi,spi-mode`` property to ``"single"`` and omit the ``cnv-gpios`` property. +This is the only wiring configuration supported when using `SPI offload support`_. + CS mode, 4-wire, without busy indicator ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -106,7 +108,6 @@ Unimplemented features ---------------------- - ``BUSY`` indication -- ``TURBO`` mode Device attributes @@ -147,6 +148,27 @@ AD7986 is a fully-differential ADC and has the following attributes: In "chain" mode, additional chips will appear as additional voltage input channels, e.g. ``in_voltage2-voltage3_raw``. +SPI offload support +=================== + +To be able to achieve the maximum sample rate, the driver can be used with the +`AXI SPI Engine`_ to provide SPI offload support. + +.. _AXI SPI Engine: http://analogdevicesinc.github.io/hdl/projects/pulsar_adc/index.html + +When SPI offload is being used, some attributes will be different. + +* ``trigger`` directory is removed. +* ``in_voltage0_sampling_frequency`` attribute is added for setting the sample + rate. +* ``in_voltage0_sampling_frequency_available`` attribute is added for querying + the max sample rate. +* ``timestamp`` channel is removed. +* Buffer data format may be different compared to when offload is not used, + e.g. the ``in_voltage0_type`` attribute. + +If the ``turbo-gpios`` property is present in the device tree, the driver will +turn on TURBO during buffered reads and turn it off otherwise. Device buffers ==============