From: Ethan Nelson-Moore Date: Fri, 23 Jan 2026 03:55:47 +0000 (-0800) Subject: pps: generators: remove broken pps_gen_parport driver X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0bb23328ab6cab866eb096ae3714a295c6f67c0f;p=thirdparty%2Flinux.git pps: generators: remove broken pps_gen_parport driver This driver was introduced in January 2011 and has been marked BROKEN for almost its entire existence, since commit 95b90afec301 ("pps: make pps_gen_parport depend on BROKEN") in March 2011. It is unlikely anyone will fix the driver at this point. Signed-off-by: Ethan Nelson-Moore Acked-by: Rodolfo Giometti Link: https://patch.msgid.link/20260123035607.22340-1-enelsonmoore@gmail.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/pps/generators/Kconfig b/drivers/pps/generators/Kconfig index b3f340ed31630..4ef02b3f25766 100644 --- a/drivers/pps/generators/Kconfig +++ b/drivers/pps/generators/Kconfig @@ -23,14 +23,6 @@ config PPS_GENERATOR_DUMMY This driver can also be built as a module. If so, the module will be called pps_gen-dummy. -config PPS_GENERATOR_PARPORT - tristate "Parallel port PPS signal generator" - depends on PARPORT && BROKEN - help - If you say yes here you get support for a PPS signal generator which - utilizes STROBE pin of a parallel port to send PPS signals. It uses - parport abstraction layer and hrtimers to precisely control the signal. - config PPS_GENERATOR_TIO tristate "TIO PPS signal generator" depends on X86 && CPU_SUP_INTEL diff --git a/drivers/pps/generators/Makefile b/drivers/pps/generators/Makefile index e109920e8a2dd..5d38774b4a565 100644 --- a/drivers/pps/generators/Makefile +++ b/drivers/pps/generators/Makefile @@ -7,7 +7,6 @@ pps_gen_core-y := pps_gen.o sysfs.o obj-$(CONFIG_PPS_GENERATOR) := pps_gen_core.o obj-$(CONFIG_PPS_GENERATOR_DUMMY) += pps_gen-dummy.o -obj-$(CONFIG_PPS_GENERATOR_PARPORT) += pps_gen_parport.o obj-$(CONFIG_PPS_GENERATOR_TIO) += pps_gen_tio.o ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG diff --git a/drivers/pps/generators/pps_gen_parport.c b/drivers/pps/generators/pps_gen_parport.c deleted file mode 100644 index 05bbf8d30ef18..0000000000000 --- a/drivers/pps/generators/pps_gen_parport.c +++ /dev/null @@ -1,238 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * pps_gen_parport.c -- kernel parallel port PPS signal generator - * - * Copyright (C) 2009 Alexander Gordeev - */ - - -/* - * TODO: - * fix issues when realtime clock is adjusted in a leap - */ - -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#include -#include -#include -#include -#include -#include - -#define SIGNAL 0 -#define NO_SIGNAL PARPORT_CONTROL_STROBE - -/* module parameters */ - -#define SEND_DELAY_MAX 100000 - -static unsigned int send_delay = 30000; -MODULE_PARM_DESC(delay, - "Delay between setting and dropping the signal (ns)"); -module_param_named(delay, send_delay, uint, 0); - - -#define SAFETY_INTERVAL 3000 /* set the hrtimer earlier for safety (ns) */ - -/* internal per port structure */ -struct pps_generator_pp { - struct pardevice *pardev; /* parport device */ - struct hrtimer timer; - long port_write_time; /* calibrated port write time (ns) */ -}; - -static struct pps_generator_pp device = { - .pardev = NULL, -}; - -static int attached; - -/* calibrated time between a hrtimer event and the reaction */ -static long hrtimer_error = SAFETY_INTERVAL; - -/* the kernel hrtimer event */ -static enum hrtimer_restart hrtimer_event(struct hrtimer *timer) -{ - struct timespec64 expire_time, ts1, ts2, ts3, dts; - struct pps_generator_pp *dev; - struct parport *port; - long lim, delta; - unsigned long flags; - - /* We have to disable interrupts here. The idea is to prevent - * other interrupts on the same processor to introduce random - * lags while polling the clock. ktime_get_real_ts64() takes <1us on - * most machines while other interrupt handlers can take much - * more potentially. - * - * NB: approx time with blocked interrupts = - * send_delay + 3 * SAFETY_INTERVAL - */ - local_irq_save(flags); - - /* first of all we get the time stamp... */ - ktime_get_real_ts64(&ts1); - expire_time = ktime_to_timespec64(hrtimer_get_softexpires(timer)); - dev = container_of(timer, struct pps_generator_pp, timer); - lim = NSEC_PER_SEC - send_delay - dev->port_write_time; - - /* check if we are late */ - if (expire_time.tv_sec != ts1.tv_sec || ts1.tv_nsec > lim) { - local_irq_restore(flags); - pr_err("we are late this time %ptSp\n", &ts1); - goto done; - } - - /* busy loop until the time is right for an assert edge */ - do { - ktime_get_real_ts64(&ts2); - } while (expire_time.tv_sec == ts2.tv_sec && ts2.tv_nsec < lim); - - /* set the signal */ - port = dev->pardev->port; - port->ops->write_control(port, SIGNAL); - - /* busy loop until the time is right for a clear edge */ - lim = NSEC_PER_SEC - dev->port_write_time; - do { - ktime_get_real_ts64(&ts2); - } while (expire_time.tv_sec == ts2.tv_sec && ts2.tv_nsec < lim); - - /* unset the signal */ - port->ops->write_control(port, NO_SIGNAL); - - ktime_get_real_ts64(&ts3); - - local_irq_restore(flags); - - /* update calibrated port write time */ - dts = timespec64_sub(ts3, ts2); - dev->port_write_time = - (dev->port_write_time + timespec64_to_ns(&dts)) >> 1; - -done: - /* update calibrated hrtimer error */ - dts = timespec64_sub(ts1, expire_time); - delta = timespec64_to_ns(&dts); - /* If the new error value is bigger then the old, use the new - * value, if not then slowly move towards the new value. This - * way it should be safe in bad conditions and efficient in - * good conditions. - */ - if (delta >= hrtimer_error) - hrtimer_error = delta; - else - hrtimer_error = (3 * hrtimer_error + delta) >> 2; - - /* update the hrtimer expire time */ - hrtimer_set_expires(timer, - ktime_set(expire_time.tv_sec + 1, - NSEC_PER_SEC - (send_delay + - dev->port_write_time + SAFETY_INTERVAL + - 2 * hrtimer_error))); - - return HRTIMER_RESTART; -} - -/* calibrate port write time */ -#define PORT_NTESTS_SHIFT 5 -static void calibrate_port(struct pps_generator_pp *dev) -{ - struct parport *port = dev->pardev->port; - int i; - long acc = 0; - - for (i = 0; i < (1 << PORT_NTESTS_SHIFT); i++) { - struct timespec64 a, b; - unsigned long irq_flags; - - local_irq_save(irq_flags); - ktime_get_real_ts64(&a); - port->ops->write_control(port, NO_SIGNAL); - ktime_get_real_ts64(&b); - local_irq_restore(irq_flags); - - b = timespec64_sub(b, a); - acc += timespec64_to_ns(&b); - } - - dev->port_write_time = acc >> PORT_NTESTS_SHIFT; - pr_info("port write takes %ldns\n", dev->port_write_time); -} - -static inline ktime_t next_intr_time(struct pps_generator_pp *dev) -{ - struct timespec64 ts; - - ktime_get_real_ts64(&ts); - - return ktime_set(ts.tv_sec + - ((ts.tv_nsec > 990 * NSEC_PER_MSEC) ? 1 : 0), - NSEC_PER_SEC - (send_delay + - dev->port_write_time + 3 * SAFETY_INTERVAL)); -} - -static void parport_attach(struct parport *port) -{ - struct pardev_cb pps_cb; - - if (send_delay > SEND_DELAY_MAX) { - pr_err("delay value should be not greater then %d\n", SEND_DELAY_MAX); - return; - } - - if (attached) { - /* we already have a port */ - return; - } - - memset(&pps_cb, 0, sizeof(pps_cb)); - pps_cb.private = &device; - pps_cb.flags = PARPORT_FLAG_EXCL; - device.pardev = parport_register_dev_model(port, KBUILD_MODNAME, - &pps_cb, 0); - if (!device.pardev) { - pr_err("couldn't register with %s\n", port->name); - return; - } - - if (parport_claim_or_block(device.pardev) < 0) { - pr_err("couldn't claim %s\n", port->name); - goto err_unregister_dev; - } - - pr_info("attached to %s\n", port->name); - attached = 1; - - calibrate_port(&device); - - hrtimer_setup(&device.timer, hrtimer_event, CLOCK_REALTIME, HRTIMER_MODE_ABS); - hrtimer_start(&device.timer, next_intr_time(&device), HRTIMER_MODE_ABS); - - return; - -err_unregister_dev: - parport_unregister_device(device.pardev); -} - -static void parport_detach(struct parport *port) -{ - if (port->cad != device.pardev) - return; /* not our port */ - - hrtimer_cancel(&device.timer); - parport_release(device.pardev); - parport_unregister_device(device.pardev); -} - -static struct parport_driver pps_gen_parport_driver = { - .name = KBUILD_MODNAME, - .match_port = parport_attach, - .detach = parport_detach, -}; -module_parport_driver(pps_gen_parport_driver); - -MODULE_AUTHOR("Alexander Gordeev "); -MODULE_DESCRIPTION("parallel port PPS signal generator"); -MODULE_LICENSE("GPL");