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SubjectRe: [LinuxPPS] [PATCH 2/2] pps: new client driver using IRQs
Hi James,

В Wed, 27 Apr 2011 14:14:14 -0400
James Nuss <jamesnuss@nanometrics.ca> пишет:

> This client driver allows you to use raw IRQs as a source for PPS
> signals.
>
> This driver is based on the work by Ricardo Martins <rasm@fe.up.pt> who
> submitted an initial implementation [1] of a PPS IRQ client driver to
> the linuxpps mailing-list on Dec 3 2010.
>
> [1] http://ml.enneenne.com/pipermail/linuxpps/2010-December/004155.html
>
> Signed-off-by: James Nuss <jamesnuss@nanometrics.ca>
> Reviewed-by: Ben Gardiner <bengardiner@nanometrics.ca>
> CC: Ricardo Martins <rasm@fe.up.pt>
> ---
> NOTE: drivers/pps/clients/Kconfig does not have the obligatory statements
> regarding building the drivers as modules, even though they are all tristates.
> This was purposefully omitted from the new config item for consistency.
> This could be addressed in a separate patch.
>
> drivers/pps/clients/Kconfig | 8 ++
> drivers/pps/clients/Makefile | 1 +
> drivers/pps/clients/pps-irq.c | 169 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 178 insertions(+), 0 deletions(-)
> create mode 100644 drivers/pps/clients/pps-irq.c
>
> diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
> index 8520a7f..94b2cc6 100644
> --- a/drivers/pps/clients/Kconfig
> +++ b/drivers/pps/clients/Kconfig
> @@ -29,4 +29,12 @@ config PPS_CLIENT_PARPORT
> If you say yes here you get support for a PPS source connected
> with the interrupt pin of your parallel port.
>
> +config PPS_CLIENT_IRQ
> + tristate "PPS client based on raw IRQs"
> + depends on PPS
> + help
> + If you say yes here you get support for a PPS source based
> + on raw IRQs. To be useful, you must also register a platform
> + device with an IRQ resource, usually in your board setup.
> +
> endif
> diff --git a/drivers/pps/clients/Makefile b/drivers/pps/clients/Makefile
> index 42517da..609a332 100644
> --- a/drivers/pps/clients/Makefile
> +++ b/drivers/pps/clients/Makefile
> @@ -5,6 +5,7 @@
> obj-$(CONFIG_PPS_CLIENT_KTIMER) += pps-ktimer.o
> obj-$(CONFIG_PPS_CLIENT_LDISC) += pps-ldisc.o
> obj-$(CONFIG_PPS_CLIENT_PARPORT) += pps_parport.o
> +obj-$(CONFIG_PPS_CLIENT_IRQ) += pps-irq.o
>
> ifeq ($(CONFIG_PPS_DEBUG),y)
> EXTRA_CFLAGS += -DDEBUG
> diff --git a/drivers/pps/clients/pps-irq.c b/drivers/pps/clients/pps-irq.c
> new file mode 100644
> index 0000000..33c1bf4
> --- /dev/null
> +++ b/drivers/pps/clients/pps-irq.c
> @@ -0,0 +1,169 @@
> +/*
> + * pps-irq.c -- PPS IRQ client
> + *
> + *
> + * Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
> + * Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
> + *
> + * 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/init.h>
> +#include <linux/kernel.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/pps_kernel.h>
> +#include <linux/gpio.h>
> +#include <linux/list.h>
> +
> +#define PPS_IRQ_NAME "pps-irq"
> +#define PPS_IRQ_VERSION "1.1.0"
> +
> +/* Info for each registered platform device */
> +struct pps_irq_data {
> + int irq; /* IRQ used as PPS source */
> + struct pps_device *pps; /* PPS source device */
> + struct pps_source_info info; /* PPS source information */
> +};
> +
> +/*
> + * Report the PPS event
> + */
> +
> +static irqreturn_t pps_irq_irq_handler(int irq, void *data)
> +{
> + struct pps_irq_data *info;
> + struct pps_event_time ts;
> +
> + /* Get the time stamp first */
> + pps_get_ts(&ts);
> +
> + info = (struct pps_irq_data *)data;
> + pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int pps_irq_probe(struct platform_device *pdev)
> +{
> + struct pps_irq_data *data;
> + struct resource *res;
> + int irq;
> + int ret;
> +
> + /* Validate resource. */
> + if (pdev->num_resources != 1) {
> + pr_err(PPS_IRQ_NAME ": this driver handles only one IRQ resource");

Shouldn't the format string in pr_*/dev_* call be ended with a '\n' or I
missed something?
Also I suggest you what I was once suggested: to define pr_fmt() macro
with a module name as in drivers/pps/clients/pps_parport.c to omit
it's use in every pr_* call. :)

> + return -EINVAL;
> + }
> +
> + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> + if (res == NULL) {
> + pr_err(PPS_IRQ_NAME ": no IRQ resource was given");
> + return -EINVAL;
> + }
> +
> + if (!(res->flags & (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING))) {
> + pr_err(PPS_IRQ_NAME ": given IRQ resource must be edge triggered");
> + return -EINVAL;
> + }

I think it doesn't actually expect that both flags are set because it
always treats it as assert in the irq handler. What does your signal
look like?

> + /* Allocate space for device info */
> + data = kzalloc(sizeof(struct pps_irq_data), GFP_KERNEL);
> + if (data == NULL)
> + return -ENOMEM;
> +
> + /* Initialize PPS specific parts of the bookkeeping data structure. */
> + data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
> + PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
> + data->info.owner = THIS_MODULE;
> + snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
> + pdev->name, pdev->id);
> +
> + /* Register PPS source. */
> + irq = platform_get_irq(pdev, 0);
> + pr_info(PPS_IRQ_NAME ": registering IRQ %d as PPS source", irq);
> + data->pps = pps_register_source(&data->info, PPS_CAPTUREASSERT
> + | PPS_OFFSETASSERT);
> + if (data->pps == NULL) {
> + kfree(data);
> + pr_err(PPS_IRQ_NAME ": failed to register IRQ %d as PPS source",
> + irq);
> + return -1;
> + }
> +
> + /* Request IRQ. */
> + pr_info(PPS_IRQ_NAME ": requesting IRQ %d", irq);
> + ret = request_irq(irq, pps_irq_irq_handler,
> + res->flags & IRQF_TRIGGER_MASK,
> + data->info.name, data);
> + if (ret) {
> + pps_unregister_source(data->pps);
> + kfree(data);
> + pr_err(PPS_IRQ_NAME ": failed to acquire IRQ %d\n", irq);
> + return ret;
> + }
> + data->irq = irq;
> +
> + platform_set_drvdata(pdev, data);
> + dev_info(data->pps->dev, "Registered IRQ %d as PPS source", data->irq);
> +
> + return 0;
> +}
> +
> +static int pps_irq_remove(struct platform_device *pdev)
> +{
> + struct pps_irq_data *data = platform_get_drvdata(pdev);
> + platform_set_drvdata(pdev, NULL);
> + free_irq(data->irq, data);
> + pps_unregister_source(data->pps);
> + pr_info(PPS_IRQ_NAME ": removed IRQ %d as PPS source", data->irq);
> + kfree(data);
> + return 0;
> +}
> +
> +static struct platform_driver pps_irq_driver = {
> + .probe = pps_irq_probe,
> + .remove = __devexit_p(pps_irq_remove),
> + .driver = {
> + .name = PPS_IRQ_NAME,
> + .owner = THIS_MODULE
> + },
> +};
> +
> +static int __init pps_irq_init(void)
> +{
> + int ret = platform_driver_register(&pps_irq_driver);
> + if (ret < 0)
> + pr_err(PPS_IRQ_NAME ": failed to register platform driver");
> + return ret;
> +}
> +
> +static void __exit pps_irq_exit(void)
> +{
> + platform_driver_unregister(&pps_irq_driver);
> + pr_debug(PPS_IRQ_NAME ": unregistered platform driver");
> +}
> +
> +module_init(pps_irq_init);
> +module_exit(pps_irq_exit);
> +
> +MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
> +MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
> +MODULE_DESCRIPTION("Use raw IRQs as PPS source");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION(PPS_IRQ_VERSION);


--
Alexander
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