Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752312AbbDZT2S (ORCPT ); Sun, 26 Apr 2015 15:28:18 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:42890 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751115AbbDZT2Q (ORCPT ); Sun, 26 Apr 2015 15:28:16 -0400 Message-ID: <553D3C4D.8040105@kernel.org> Date: Sun, 26 Apr 2015 20:28:13 +0100 From: Jonathan Cameron User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Daniel Baluta CC: jlbec@evilplan.org, lars@metafoo.de, knaack.h@gmx.de, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, octavian.purdila@intel.com, pebolle@tiscali.nl, patrick.porlan@intel.com, adriana.reus@intel.com, constantin.musca@intel.com, marten@intuitiveaerial.com Subject: Re: [PATCH v4 3/4] iio: trigger: Introduce IIO hrtimer based trigger References: <1429538563-23430-1-git-send-email-daniel.baluta@intel.com> <1429538563-23430-4-git-send-email-daniel.baluta@intel.com> In-Reply-To: <1429538563-23430-4-git-send-email-daniel.baluta@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8279 Lines: 268 On 20/04/15 15:02, Daniel Baluta wrote: > This patch registers a new IIO software trigger interrupt source > based on high resolution timers. > > Notice that if configfs is enabled we create sampling_frequency > attribute allowing users to change hrtimer period (1/sampling_frequency). > > The IIO hrtimer trigger has a long history, this patch is based on > an older version from Marten and Lars-Peter. > > Signed-off-by: Marten Svanfeldt > Signed-off-by: Lars-Peter Clausen > Signed-off-by: Daniel Baluta Looks good to me - will let the series sit a little longer though for others to take a look. > --- > drivers/iio/trigger/Kconfig | 9 ++ > drivers/iio/trigger/Makefile | 2 + > drivers/iio/trigger/iio-trig-hrtimer.c | 201 +++++++++++++++++++++++++++++++++ > 3 files changed, 212 insertions(+) > create mode 100644 drivers/iio/trigger/iio-trig-hrtimer.c > > diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig > index 7999612..454665a 100644 > --- a/drivers/iio/trigger/Kconfig > +++ b/drivers/iio/trigger/Kconfig > @@ -5,6 +5,15 @@ > > menu "Triggers - standalone" > > +config IIO_HRTIMER_TRIGGER > + tristate "High resolution timer trigger" > + select IIO_SW_TRIGGER > + help > + Provides a frequency based IIO trigger using hrtimers. > + > + To compile this driver as a module, choose M here: the > + module will be called iio-trig-hrtimer. > + > config IIO_INTERRUPT_TRIGGER > tristate "Generic interrupt trigger" > help > diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile > index 0694dae..fe06eb5 100644 > --- a/drivers/iio/trigger/Makefile > +++ b/drivers/iio/trigger/Makefile > @@ -3,5 +3,7 @@ > # > > # When adding new entries keep the list in alphabetical order > + > +obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.o > obj-$(CONFIG_IIO_INTERRUPT_TRIGGER) += iio-trig-interrupt.o > obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o > diff --git a/drivers/iio/trigger/iio-trig-hrtimer.c b/drivers/iio/trigger/iio-trig-hrtimer.c > new file mode 100644 > index 0000000..5077fad > --- /dev/null > +++ b/drivers/iio/trigger/iio-trig-hrtimer.c > @@ -0,0 +1,201 @@ > +/** > + * The industrial I/O periodic hrtimer trigger driver > + * > + * Copyright (C) Intuitive Aerial AB > + * Written by Marten Svanfeldt, marten@intuitiveaerial.com > + * Copyright (C) 2012, Analog Device Inc. > + * Author: Lars-Peter Clausen > + * Copyright (C) 2015, Intel Corporation > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License version 2 as published by > + * the Free Software Foundation. > + * > + */ > +#include > +#include > +#include > + > +#include > +#include > +#include > + > +/* default sampling frequency - 100Hz */ > +#define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100 > + > +struct iio_hrtimer_info { > + struct iio_sw_trigger swt; > + struct hrtimer timer; > + unsigned long sampling_frequency; > + ktime_t period; > +}; > + > +#ifdef CONFIG_CONFIGFS_FS > +struct iio_hrtimer_info *to_iio_hrtimer_info(struct config_item *item) > +{ > + return item ? container_of(to_iio_sw_trigger(item), > + struct iio_hrtimer_info, swt) : NULL; > +} > + > +CONFIGFS_ATTR_STRUCT(iio_hrtimer_info); > + > +#define IIO_HRTIMER_INFO_ATTR(_name, _mode, _show, _store) \ > + struct iio_hrtimer_info_attribute iio_hrtimer_attr_##_name = \ > + __CONFIGFS_ATTR(_name, _mode, _show, _store) > + > +static > +ssize_t iio_hrtimer_info_show_sampling_frequency(struct iio_hrtimer_info *info, > + char *page) > +{ > + return snprintf(page, PAGE_SIZE, "%lu\n", info->sampling_frequency); > +} > + > +static > +ssize_t iio_hrtimer_info_store_sampling_frequency(struct iio_hrtimer_info *info, > + const char *page, > + size_t count) > +{ > + unsigned long val; > + int ret; > + > + ret = kstrtoul(page, 10, &val); > + if (ret) > + return ret; > + > + if (!val || val > NSEC_PER_SEC) > + return -EINVAL; > + > + info->sampling_frequency = val; > + info->period = ktime_set(0, NSEC_PER_SEC / val); > + > + return count; > +} > + > +IIO_HRTIMER_INFO_ATTR(sampling_frequency, S_IRUGO | S_IWUSR, > + iio_hrtimer_info_show_sampling_frequency, > + iio_hrtimer_info_store_sampling_frequency); > + > +static struct configfs_attribute *iio_hrtimer_attrs[] = { > + &iio_hrtimer_attr_sampling_frequency.attr, > + NULL > +}; > + > +CONFIGFS_ATTR_OPS(iio_hrtimer_info); > +static struct configfs_item_operations iio_hrtimer_ops = { > + .show_attribute = iio_hrtimer_info_attr_show, > + .store_attribute = iio_hrtimer_info_attr_store, > +}; > + > +static struct config_item_type iio_hrtimer_type = { > + .ct_item_ops = &iio_hrtimer_ops, > + .ct_attrs = iio_hrtimer_attrs, > + .ct_owner = THIS_MODULE, > +}; > + > +#endif /* CONFIGFS_FS */ > + > +static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer) > +{ > + struct iio_hrtimer_info *info; > + > + info = container_of(timer, struct iio_hrtimer_info, timer); > + > + hrtimer_forward_now(timer, info->period); > + iio_trigger_poll(info->swt.trigger); > + > + return HRTIMER_RESTART; > +} > + > +static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state) > +{ > + struct iio_hrtimer_info *trig_info; > + > + trig_info = iio_trigger_get_drvdata(trig); > + > + if (state) > + hrtimer_start(&trig_info->timer, trig_info->period, > + HRTIMER_MODE_REL); > + else > + hrtimer_cancel(&trig_info->timer); > + > + return 0; > +} > + > +static const struct iio_trigger_ops iio_hrtimer_trigger_ops = { > + .owner = THIS_MODULE, > + .set_trigger_state = iio_trig_hrtimer_set_state, > +}; > + > +static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name) > +{ > + struct iio_hrtimer_info *trig_info; > + int ret; > + > + trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL); > + if (!trig_info) > + return ERR_PTR(-ENOMEM); > + > + trig_info->swt.trigger = iio_trigger_alloc("%s", name); > + if (!trig_info->swt.trigger) { > + ret = -ENOMEM; > + goto err_free_trig_info; > + } > + > + iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info); > + trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops; > + > + hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); > + trig_info->timer.function = iio_hrtimer_trig_handler; > + > + trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY; > + trig_info->period = ktime_set(0, NSEC_PER_SEC / > + trig_info->sampling_frequency); > + > + ret = iio_trigger_register(trig_info->swt.trigger); > + if (ret) > + goto err_free_trigger; > +#ifdef CONFIG_CONFIGFS_FS > + config_group_init_type_name(&trig_info->swt.group, name, > + &iio_hrtimer_type); > +#endif > + return &trig_info->swt; > +err_free_trigger: > + iio_trigger_free(trig_info->swt.trigger); > +err_free_trig_info: > + kfree(trig_info); > + > + return ERR_PTR(ret); > +} > + > +static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt) > +{ > + struct iio_hrtimer_info *trig_info; > + > + trig_info = iio_trigger_get_drvdata(swt->trigger); > + > + hrtimer_cancel(&trig_info->timer); > + > + iio_trigger_unregister(swt->trigger); > + iio_trigger_free(swt->trigger); > + kfree(trig_info); > + > + return 0; > +} > + > +struct iio_sw_trigger_ops iio_trig_hrtimer_ops = { > + .probe = iio_trig_hrtimer_probe, > + .remove = iio_trig_hrtimer_remove, > +}; > + > +struct iio_sw_trigger_type iio_trig_hrtimer = { > + .name = "hrtimer", > + .owner = THIS_MODULE, > + .ops = &iio_trig_hrtimer_ops, > +}; > + > +module_iio_sw_trigger_driver(iio_trig_hrtimer); > + > +MODULE_AUTHOR("Marten Svanfeldt "); > +MODULE_AUTHOR("Daniel Baluta "); > +MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem"); > +MODULE_LICENSE("GPL v2"); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/