From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1020622F768; Fri, 30 May 2025 17:45:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748627144; cv=none; b=jWSLPlUR9jvB4gMNbw6sNCqQJNMrUpgAeiRC+GGyKL6OEbUetTrmzwmEzYFV9U6cTRslOb4ZiQ9OUSoAlJ6YQxR4Ejhh3m7CWdjv/lvxH1Zc4DZ6ymiooDfw1GfjTL4iID9v8s7x9iazCp7G3izTdGad25ja9WYA6/8YBQB2Ias= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748627144; c=relaxed/simple; bh=KCuQIxE/UbX7bNhWPslmmbXQbkL9HQAVn32a/t8FsGA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EBA4w8OGgJJ7UKUJbUxT9dUI3uVdqBu10yDHaC5mLB3Y22HGF7xCwG0VU0MJ10fXljzwtiwN6Rk/kp3zNrRahSGmCBEGBMSosFkG/8475SNXBeg7W3kSWE8SWDhCxhdVuiF+Vkc9vMcH7mt5BUMVqaEvLs93OKR41Xgf7IJ+oyE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org; spf=fail smtp.mailfrom=kernel.org; arc=none smtp.client-ip=192.198.163.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=kernel.org X-CSE-ConnectionGUID: mchwAGlZT/+Ek9uY72rrpw== X-CSE-MsgGUID: FMGMifi3RBWBEChEpM5xKQ== X-IronPort-AV: E=McAfee;i="6700,10204,11449"; a="76118855" X-IronPort-AV: E=Sophos;i="6.16,196,1744095600"; d="scan'208";a="76118855" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 May 2025 10:45:40 -0700 X-CSE-ConnectionGUID: v38ue9yQThCTQBuMxdq/qg== X-CSE-MsgGUID: IVoxASSqQx2QwsVCPT4q6g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,196,1744095600"; d="scan'208";a="174812793" Received: from smile.fi.intel.com ([10.237.72.52]) by fmviesa001.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 May 2025 10:45:36 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98.2) (envelope-from ) id 1uL3nQ-000000024VO-35JF; Fri, 30 May 2025 20:45:32 +0300 Date: Fri, 30 May 2025 20:45:32 +0300 From: Andy Shevchenko To: Jonathan Santos Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org, nuno.sa@analog.com, Michael.Hennerich@analog.com, marcelo.schmitt@analog.com, jic23@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, marcelo.schmitt1@gmail.com, linus.walleij@linaro.org, brgl@bgdev.pl, lgirdwood@gmail.com, broonie@kernel.org, jonath4nns@gmail.com, dlechner@baylibre.com, rafael@kernel.org, djrscally@gmail.com Subject: Re: [PATCH v9 09/12] iio: adc: ad7768-1: add support for Synchronization over SPI Message-ID: References: <27cccb51cc56f1bb57cb06d279854a503d779e25.1748447035.git.Jonathan.Santos@analog.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27cccb51cc56f1bb57cb06d279854a503d779e25.1748447035.git.Jonathan.Santos@analog.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Thu, May 29, 2025 at 07:50:29PM -0300, Jonathan Santos wrote: > The synchronization method using GPIO requires the generated pulse to be > truly synchronous with the base MCLK signal. When it is not possible to > do that in hardware, the datasheet recommends using synchronization over > SPI, where the generated pulse is already synchronous with MCLK. This > requires the SYNC_OUT pin to be connected to the SYNC_IN pin. > > Use trigger-sources property to enable device synchronization over SPI > and multi-device synchronization while replacing sync-in-gpios property. ... > struct ad7768_state { > struct iio_trigger *trig; > struct gpio_desc *gpio_sync_in; > struct gpio_desc *gpio_reset; > + bool en_spi_sync; I'm wondering if moving this... > const char *labels[ARRAY_SIZE(ad7768_channels)]; > struct gpio_chip gpiochip; ...to here saves a few bytes in accordance to `pahole`. > }; ... > +static int ad7768_trigger_sources_sync_setup(struct device *dev, > + struct fwnode_handle *dev_fwnode, > + struct ad7768_state *st) > +{ > + struct fwnode_reference_args args; > + > + struct fwnode_handle *fwnode __free(fwnode_handle) = > + fwnode_find_reference_args(dev_fwnode, "trigger-sources", > + "#trigger-source-cells", 0, > + AD7768_TRIGGER_SOURCE_SYNC_IDX, &args); I don't see how args are being used. This puts in doubt the need of the first patch. > + if (IS_ERR(fwnode)) > + return PTR_ERR(fwnode); > + > + /* First, try getting the GPIO trigger source */ > + if (fwnode_device_is_compatible(fwnode, "gpio-trigger")) { > + st->gpio_sync_in = devm_fwnode_gpiod_get_index(dev, fwnode, > + NULL, > + 0, > + GPIOD_OUT_LOW, > + "sync-in"); > + return PTR_ERR_OR_ZERO(st->gpio_sync_in); > + } > + > + /* > + * TODO: Support the other cases when we have a trigger subsystem > + * to reliably handle other types of devices as trigger sources. > + * > + * For now, return an error message. For self triggering, omit the > + * trigger-sources property. > + */ > + return dev_err_probe(dev, -EOPNOTSUPP, "Invalid synchronization trigger source\n"); > +} ... > +static int ad7768_trigger_sources_get_sync(struct device *dev, > + struct ad7768_state *st) > +{ > + struct fwnode_handle *dev_fwnode = dev_fwnode(dev); Call it just fwnode. > + /* > + * The AD7768-1 allows two primary methods for driving the SYNC_IN pin > + * to synchronize one or more devices: > + * 1. Using an external GPIO. > + * 2. Using a SPI command, where the SYNC_OUT pin generates a > + * synchronization pulse that drives the SYNC_IN pin. > + */ > + if (fwnode_property_present(dev_fwnode, "trigger-sources")) > + return ad7768_trigger_sources_sync_setup(dev, dev_fwnode, st); > + > + /* > + * In the absence of trigger-sources property, enable self > + * synchronization over SPI (SYNC_OUT). > + */ > + st->en_spi_sync = true; > + return 0; > +} -- With Best Regards, Andy Shevchenko