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 72280C48BDF for ; Wed, 9 Jun 2021 16:49:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5915C613CD for ; Wed, 9 Jun 2021 16:49:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230083AbhFIQvU (ORCPT ); Wed, 9 Jun 2021 12:51:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:43002 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230103AbhFIQvT (ORCPT ); Wed, 9 Jun 2021 12:51:19 -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 9797C613CB; Wed, 9 Jun 2021 16:49:22 +0000 (UTC) Date: Wed, 9 Jun 2021 17:51:15 +0100 From: Jonathan Cameron To: William Breathitt Gray Cc: Jonathan.Cameron@Huawei.com, linux-stm32@st-md-mailman.stormreply.com, kernel@pengutronix.de, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [RESEND PATCH v11 22/33] counter: Internalize sysfs interface code Message-ID: <20210609175115.1692f5dc@jic23-huawei> In-Reply-To: <87dec6c889e40068ed27cbb3e66a6376856e2267.1623201082.git.vilhelm.gray@gmail.com> References: <87dec6c889e40068ed27cbb3e66a6376856e2267.1623201082.git.vilhelm.gray@gmail.com> X-Mailer: Claws Mail 3.17.8 (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 Wed, 9 Jun 2021 23:11:45 +0900 William Breathitt Gray wrote: > This is a reimplementation of the Generic Counter driver interface. > There are no modifications to the Counter subsystem userspace interface, > so existing userspace applications should continue to run seamlessly. > > The purpose of this patch is to internalize the sysfs interface code > among the various counter drivers into a shared module. Counter drivers > pass and take data natively (i.e. u8, u64, etc.) and the shared counter > module handles the translation between the sysfs interface and the > device drivers. This guarantees a standard userspace interface for all > counter drivers, and helps generalize the Generic Counter driver ABI in > order to support the Generic Counter chrdev interface (introduced in a > subsequent patch) without significant changes to the existing counter > drivers. > > Note, Counter device registration is the same as before: drivers > populate a struct counter_device with components and callbacks, then > pass the structure to the devm_counter_register function. However, > what's different now is how the Counter subsystem code handles this > registration internally. > > Whereas before callbacks would interact directly with sysfs data, this > interaction is now abstracted and instead callbacks interact with native > C data types. The counter_comp structure forms the basis for Counter > extensions. > > The counter-sysfs.c file contains the code to parse through the > counter_device structure and register the requested components and > extensions. Attributes are created and populated based on type, with > respective translation functions to handle the mapping between sysfs and > the counter driver callbacks. > > The translation performed for each attribute is straightforward: the > attribute type and data is parsed from the counter_attribute structure, > the respective counter driver read/write callback is called, and sysfs > I/O is handled before or after the driver read/write function is called. > > Cc: Syed Nayyar Waris > Cc: Jarkko Nikula > Cc: Patrick Havelange > Cc: Kamel Bouhara > Cc: Fabrice Gasnier > Cc: Maxime Coquelin > Cc: Alexandre Torgue > Cc: Dan Carpenter > Reviewed-by: David Lechner > Tested-by: David Lechner > Signed-off-by: William Breathitt Gray Given you will probably do a v12 anyway, a few comments inline. Jonathan > --- > MAINTAINERS | 1 - > drivers/counter/104-quad-8.c | 449 +++---- > drivers/counter/Makefile | 1 + > drivers/counter/counter-core.c | 155 +++ > drivers/counter/counter-sysfs.c | 846 +++++++++++++ > drivers/counter/counter-sysfs.h | 13 + > drivers/counter/counter.c | 1496 ----------------------- > drivers/counter/ftm-quaddec.c | 56 +- > drivers/counter/intel-qep.c | 144 +-- > drivers/counter/interrupt-cnt.c | 62 +- > drivers/counter/microchip-tcb-capture.c | 93 +- > drivers/counter/stm32-lptimer-cnt.c | 162 ++- > drivers/counter/stm32-timer-cnt.c | 147 +-- > drivers/counter/ti-eqep.c | 180 +-- > include/linux/counter.h | 629 +++++----- > include/linux/counter_enum.h | 45 - > 16 files changed, 1918 insertions(+), 2561 deletions(-) > create mode 100644 drivers/counter/counter-core.c > create mode 100644 drivers/counter/counter-sysfs.c > create mode 100644 drivers/counter/counter-sysfs.h > delete mode 100644 drivers/counter/counter.c > delete mode 100644 include/linux/counter_enum.h > ... > diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c > new file mode 100644 > index 000000000000..e7dd6ea01c8a > --- /dev/null > +++ b/drivers/counter/counter-core.c > @@ -0,0 +1,155 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Generic Counter interface > + * Copyright (C) 2020 William Breathitt Gray > + */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "counter-sysfs.h" > + > +/* Provides a unique ID for each counter device */ > +static DEFINE_IDA(counter_ida); > + ... > +int counter_register(struct counter_device *const counter) > +{ > + struct device *const dev = &counter->dev; > + int id; > + int err; > + > + /* Acquire unique ID */ > + id = ida_alloc(&counter_ida, GFP_KERNEL); > + if (id < 0) > + return id; > + > + /* Configure device structure for Counter */ > + dev->id = id; > + dev->type = &counter_device_type; > + dev->bus = &counter_bus_type; > + if (counter->parent) { > + dev->parent = counter->parent; > + dev->of_node = counter->parent->of_node; > + } > + device_initialize(dev); > + dev_set_drvdata(dev, counter); > + > + /* Add Counter sysfs attributes */ > + err = counter_sysfs_add(counter); > + if (err < 0) > + goto err_free_id; > + > + /* Add device to system */ > + err = device_add(dev); > + if (err < 0) > + goto err_free_id; > + > + return 0; > + > +err_free_id: > + put_device(dev); > + return err; > +} > +EXPORT_SYMBOL_GPL(counter_register); > + > +/** > + * counter_unregister - unregister Counter from the system > + * @counter: pointer to Counter to unregister > + * > + * The Counter is unregistered from the system; all allocated memory is freed. If we are being fussy. This isn't necessarily true. If the reference goes down to 0 it will be freed, but in theory that could happen later than this call. I'm guessing we will have get_device() calls once the chrdev is in place. > + */ > +void counter_unregister(struct counter_device *const counter) > +{ > + if (!counter) > + return; > + > + device_unregister(&counter->dev); > +} > +EXPORT_SYMBOL_GPL(counter_unregister); > + > +static void devm_counter_release(struct device *dev, void *res) > +{ > + counter_unregister(*(struct counter_device **)res); > +} > + > +/** > + * devm_counter_register - Resource-managed counter_register > + * @dev: device to allocate counter_device for > + * @counter: pointer to Counter to register > + * > + * Managed counter_register. The Counter registered with this function is > + * automatically unregistered on driver detach. This function calls > + * counter_register internally. Refer to that function for more information. > + * > + * RETURNS: > + * 0 on success, negative error number on failure. > + */ > +int devm_counter_register(struct device *dev, > + struct counter_device *const counter) > +{ > + struct counter_device **ptr; > + int err; > + > + ptr = devres_alloc(devm_counter_release, sizeof(*ptr), GFP_KERNEL); > + if (!ptr) > + return -ENOMEM; If you look at how devm_iio_device_register() is now done in the togreg branch of iio.git, you'll see it now just uses devm_add_action_or_reset() internally. I think you could do something similar here and reduce boilerplate a little. > + > + err = counter_register(counter); > + if (err < 0) { > + devres_free(ptr); > + return err; > + } > + > + *ptr = counter; > + devres_add(dev, ptr); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(devm_counter_register); > + > +static int __init counter_init(void) > +{ > + return bus_register(&counter_bus_type); > +} > + > +static void __exit counter_exit(void) > +{ > + bus_unregister(&counter_bus_type); > +} > + > +subsys_initcall(counter_init); > +module_exit(counter_exit); > + > +MODULE_AUTHOR("William Breathitt Gray "); > +MODULE_DESCRIPTION("Generic Counter interface"); > +MODULE_LICENSE("GPL v2"); > diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c > new file mode 100644 > index 000000000000..07588130600a > --- /dev/null > +++ b/drivers/counter/counter-sysfs.c > @@ -0,0 +1,846 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Generic Counter sysfs interface > + * Copyright (C) 2020 William Breathitt Gray > + */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "counter-sysfs.h" > + ...