Messages in this thread | | | Date | Thu, 8 Jan 2009 12:29:59 +0100 | From | "Hans J. Koch" <> | Subject | Re: [PATCH 1/2] Driver for user access to internal timer |
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On Thu, Jan 08, 2009 at 11:05:30AM +0100, Davide Rizzo wrote: > Allows user programs to manage internal timers, through virtual files > frequency and duty. > If pwm_one_shot is implemented, it allows also waiting for one-shot period. > > Signed-off-by: Davide Rizzo <elpa-rizzo@gmail.com> > --- > diff -urNp linux-2.6.28/drivers/uio/Kconfig
Davide, please don't use drivers/uio/ for things that are no UIO drivers.
Thanks, Hans
> linux-2.6.28.elpa/drivers/uio/Kconfig > --- linux-2.6.28/drivers/uio/Kconfig 2008-12-25 00:26:37.000000000 +0100 > +++ linux-2.6.28.elpa/drivers/uio/Kconfig 2009-01-07 18:58:10.000000000 +0100 > @@ -13,6 +13,26@ menuconfig UIO > > if UIO > > +config UIO_TIMER > + tristate "General purpose timer driver" > + default y > + ---help--- > + This driver allows to configure and control general purpose timers > + from user level code. > + To use driver to generate one-shot interrupt-terminated delays, the > + function pwm_one_shot() must be implemented in low-level drivers > + Currently it's implemented only on Samsung S3C24xx platforms. > + > +config UIO_TIMER_ONESHOT > + bool "Timer driver uses one-shot mode" > + depends on PLAT_S3C > + default y > + ---help--- > + Enable this to allow general purpose timer driver to use timers > + in one-shot mode. For this to work, the function pwm_one_shot() > + must be implemented in low-level drivers. > + Currently it's implemented only on Samsung S3C24xx platforms. > + > config UIO_CIF > tristate "generic Hilscher CIF Card driver" > depends on PCI > diff -urNp linux-2.6.28/drivers/uio/Makefile > linux-2.6.28.elpa/drivers/uio/Makefile > --- linux-2.6.28/drivers/uio/Makefile 2008-12-25 00:26:37.000000000 +0100 > +++ linux-2.6.28.elpa/drivers/uio/Makefile 2009-01-06 18:20:17.000000000 +0100 > @@ -1,4 +1,5@@ > obj-$(CONFIG_UIO) += uio.o > +obj-$(CONFIG_UIO_TIMER) += timer.o > obj-$(CONFIG_UIO_CIF) += uio_cif.o > obj-$(CONFIG_UIO_PDRV) += uio_pdrv.o > obj-$(CONFIG_UIO_PDRV_GENIRQ) += uio_pdrv_genirq.o > diff -urNp linux-2.6.28/drivers/uio/timer.c > linux-2.6.28.elpa/drivers/uio/timer.c > --- linux-2.6.28/drivers/uio/timer.c 1970-01-01 01:00:00.000000000 +0100 > +++ linux-2.6.28.elpa/drivers/uio/timer.c 2009-01-07 19:02:25.000000000 +0100 > @@ -0,0 +1,302 @@ > +/* > + drivers/misc/timer.c > + > + Written Jan 2009 by Davide Rizzo <elpa-rizzo@gmail.com> > + > + This driver allows user to access internal timers > + You can use any timer to generate a fixed frequency signal, or to wait for a > + defined short time (if hardware can do it). > + To generate a PWM signal, you have to write the frequency value in Hz into the > + virtual file "freq". After that you can program the duty cycle in the virtual > + file "duty", in 1/1000 units (500 = 50%). > + To wait for a time, you have to write the number of microseconds in virtual > + file "wait". Reading from same file will complete when timer will expire. > + > + This program is free software; you can redistribute it and/or modify > + it under the terms of the GNU General Public License as published by > + the Free Software Foundation; either version 2 of the License, or > + (at your option) any later version. > + > + This program is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + GNU General Public License for more details. > + > + You should have received a copy of the GNU General Public License > + along with this program; if not, write to the Free Software > + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > +*/ > + > +#include <linux/platform_device.h> > +#include <linux/err.h> > +#include <linux/pwm.h> > + > +struct timer_info { > + int id; > + struct pwm_device *pwm; > + unsigned long period_ns, duty_ns; > + struct mutex mtx; > +#ifdef CONFIG_UIO_TIMER_ONESHOT > + int flag; > + wait_queue_head_t wq; > +#endif /* CONFIG_UIO_TIMER_ONESHOT */ > +}; > + > +#ifdef CONFIG_UIO_TIMER_ONESHOT > +static void expired(struct pwm_device *pwm, void *arg) > +{ > + struct timer_info *info = dev_get_drvdata((struct device *)arg); > + > + info->flag = 1; > + > + wake_up_interruptible(&info->wq); > +} > + > +/* Delay is in usec */ > +static ssize_t wait_store(struct device *dev, struct device_attribute *attr, > + const char *buffer, size_t count) > +{ > + struct timer_info *info = dev_get_drvdata(dev); > + unsigned long delay; > + int err = strict_strtoul(buffer, 10, &delay); > + > + if (err) > + return err; > + > + mutex_lock(&info->mtx); > + > + info->flag = 0; > + pwm_one_shot(info->pwm, delay * 1000, expired, dev); > + > + mutex_unlock(&info->mtx); > + > + return count; > +} > + > +/* Waits for delay */ > +static ssize_t wait_show(struct device *dev, struct device_attribute *attr, > + char *buffer) > +{ > + struct timer_info *info = dev_get_drvdata(dev); > + int ret; > + > + mutex_lock(&info->mtx); > + > + /* !=0 if interrupted by some other signal */ > + ret = wait_event_interruptible(info->wq, info->flag); > + > + mutex_unlock(&info->mtx); > + > + snprintf(buffer, PAGE_SIZE - 1, "%d\n", ret); > + return strlen(buffer); > +} > +#endif /* CONFIG_UIO_TIMER_ONESHOT */ > + > +#define NS_IN_HZ (1000000000UL) > + > +/* Freq is in Hz */ > +static ssize_t freq_store(struct device *dev, struct device_attribute *attr, > + const char *buffer, size_t count) > +{ > + struct timer_info *info = dev_get_drvdata(dev); > + unsigned long output_freq; > + int err = strict_strtoul(buffer, 10, &output_freq); > + if (err) > + return err; > + > + mutex_lock(&info->mtx); > + > + if (output_freq == 0) { /* Stop timer */ > + pwm_disable(info->pwm); > + info->period_ns = 0; > + info->duty_ns = 0; > + } else { > + unsigned long new_period = NS_IN_HZ / output_freq; > + if (info->period_ns == 0) > + info->duty_ns = new_period / 2; > + else { > + unsigned long long ll = (unsigned long long)new_period * > + info->duty_ns ; > + do_div(ll, info->period_ns); > + info->duty_ns = ll; > + } > + info->period_ns = new_period; > + pwm_config(info->pwm, info->duty_ns, info->period_ns); > + pwm_enable(info->pwm); > + } > + > + mutex_unlock(&info->mtx); > + > + return count; > +} > + > +/* Freq is in Hz */ > +static ssize_t freq_show(struct device *dev, struct device_attribute *attr, > + char *buffer) > +{ > + struct timer_info *info = dev_get_drvdata(dev); > + if (info->period_ns) > + snprintf(buffer, PAGE_SIZE - 1, "%ld\n", NS_IN_HZ / > + info->period_ns); > + else > + strlcpy(buffer, "0\n", PAGE_SIZE); > + return strlen(buffer); > +} > + > +/* Duty is in 1/1000 units */ > +static ssize_t duty_store(struct device *dev, struct device_attribute *attr, > + const char *buffer, size_t count) > +{ > + struct timer_info *info = dev_get_drvdata(dev); > + unsigned long duty; > + int err = strict_strtoul(buffer, 10, &duty); > + if (err) > + return err; > + if (duty > 1000) > + return -ERANGE; > + > + mutex_lock(&info->mtx); > + > + if ((info->period_ns == 0) || (duty == 0)) { /* Stop timer */ > + info->duty_ns = 0; > + pwm_disable(info->pwm); > + } else { > + unsigned long long ll = (unsigned long long)duty * > + info->period_ns; > + do_div(ll, 1000); > + info->duty_ns = ll; > + pwm_config(info->pwm, info->duty_ns, info->period_ns); > + pwm_enable(info->pwm); > + } > + > + mutex_unlock(&info->mtx); > + > + return count; > +} > + > +/* Duty is in 1/1000 units */ > +static ssize_t duty_show(struct device *dev, struct device_attribute *attr, > + char *buffer) > +{ > + struct timer_info *info = dev_get_drvdata(dev); > + > + mutex_lock(&info->mtx); > + > + if (info->period_ns) { > + volatile unsigned long long ll = info->duty_ns * 1000; > + do_div(ll, info->period_ns); > + snprintf(buffer, PAGE_SIZE - 1, "%ld\n", (long int)ll); > + } else > + strlcpy(buffer, "0\n", PAGE_SIZE); > + > + mutex_unlock(&info->mtx); > + > + return strlen(buffer); > +} > + > +#ifdef CONFIG_UIO_TIMER_ONESHOT > +static DEVICE_ATTR(wait, S_IRUGO | S_IWUSR, wait_show, wait_store); > +#endif /* CONFIG_UIO_TIMER_ONESHOT */ > +static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR, freq_show, freq_store); > +static DEVICE_ATTR(duty, S_IRUGO | S_IWUSR, duty_show, duty_store); > + > +static int timer_probe(struct platform_device *pdev) > +{ > + struct timer_info *info; > + int err; > + info = kzalloc(sizeof(*info), GFP_KERNEL); > + if (!info) { > + dev_err(&pdev->dev, "out of kernel memory\n"); > + err = -ENOMEM; > + goto fail_malloc; > + } > + platform_set_drvdata(pdev, info); > + mutex_init(&info->mtx); > + info->pwm = pwm_request(pdev->id, "timer driver"); > + if (IS_ERR(info->pwm)) { > + err = PTR_ERR(info->pwm); > + goto fail_req; > + } > +#ifdef CONFIG_UIO_TIMER_ONESHOT > + init_waitqueue_head(&info->wq); > + info->flag = 1; > + err = device_create_file(&pdev->dev, &dev_attr_wait); > + if (err) { > + dev_err(&pdev->dev, "Unable to create wait virtual file\n"); > + goto fail_wait; > + } > +#endif /* CONFIG_UIO_TIMER_ONESHOT */ > + err = device_create_file(&pdev->dev, &dev_attr_frequency); > + if (err) { > + dev_err(&pdev->dev, "Unable to create freq virtual file\n"); > + goto fail_freq; > + } > + err = device_create_file(&pdev->dev, &dev_attr_duty); > + if (err) { > + dev_err(&pdev->dev, "Unable to create duty virtual file\n"); > + goto fail_duty; > + } > + dev_notice(&pdev->dev, "timer %d device driver loaded OK\n", pdev->id); > + return 0; > + > +fail_duty: > + device_remove_file(&pdev->dev, &dev_attr_frequency); > +fail_freq: > +#ifdef CONFIG_UIO_TIMER_ONESHOT > + device_remove_file(&pdev->dev, &dev_attr_wait); > +fail_wait: > +#endif /* CONFIG_UIO_TIMER_ONESHOT */ > + pwm_free(info->pwm); > +fail_req: > + platform_set_drvdata(pdev, NULL); > + kfree(info); > +fail_malloc: > + return err; > +} > + > +static int timer_remove(struct platform_device *pdev) > +{ > + struct timer_info *info = platform_get_drvdata(pdev); > + > + mutex_lock(&info->mtx); > + > + device_remove_file(&pdev->dev, &dev_attr_duty); > + device_remove_file(&pdev->dev, &dev_attr_frequency); > +#ifdef CONFIG_UIO_TIMER_ONESHOT > + device_remove_file(&pdev->dev, &dev_attr_wait); > +#endif /* CONFIG_UIO_TIMER_ONESHOT */ > + pwm_free(info->pwm); > + platform_set_drvdata(pdev, NULL); > + > + mutex_unlock(&info->mtx); > + > + kfree(info); > + return 0; > +} > + > +static struct platform_driver timer_driver = { > + .probe = timer_probe, > + .remove = timer_remove, > + .driver = { > + .name = "timer", > + .owner = THIS_MODULE, > + }, > +}; > + > +static int __init timer_init_module(void) > +{ > + return platform_driver_register(&timer_driver); > +} > + > +static void __exit timer_cleanup_module(void) > +{ > + platform_driver_unregister(&timer_driver); > +} > + > +module_init(timer_init_module); > +module_exit(timer_cleanup_module); > + > +MODULE_AUTHOR("Davide Rizzo <elpa-rizzo@gmail.com>"); > +MODULE_DESCRIPTION("Timers driver"); > +MODULE_SUPPORTED_DEVICE("timers"); > +MODULE_LICENSE("GPL");
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