Re: [LinuxPPS] [PATCH v2 2/2] pps: new client driver using GPIO

From: Rodolfo Giometti
Date: Tue Jul 05 2011 - 04:11:17 EST

Next message: Ankita Garg: "[PATCH 2/5] memref module to walk the process page table"
Previous message: Florian Mickler: "Re: [PATCH] ACPI: Fix lockdep false positives in acpi_power_off()"
In reply to: James Nuss: "[PATCH v2 2/2] pps: new client driver using GPIO"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On Mon, Jul 04, 2011 at 12:29:29PM -0400, James Nuss wrote:
> This client driver allows you to use a GPIO pin as a source for PPS
> signals. Platform data [1] are used to specify the GPIO pin number, label,
> assert event edge type, and whether clear events are captured.
>
> This driver is based on the work by Ricardo Martins <rasm@xxxxxxxx> who
> submitted an initial implementation [2] of a PPS IRQ client driver to
> the linuxpps mailing-list on Dec 3 2010.
>
> [1] include/linux/pps-gpio.h
> [2] http://ml.enneenne.com/pipermail/linuxpps/2010-December/004155.html
>
> Signed-off-by: James Nuss <jamesnuss@xxxxxxxxxxxxxx>
> CC: Ricardo Martins <rasm@xxxxxxxx>
> ---
> drivers/pps/clients/Kconfig | 9 ++
> drivers/pps/clients/Makefile | 1 +
> drivers/pps/clients/pps-gpio.c | 218 ++++++++++++++++++++++++++++++++++++++++
> include/linux/pps-gpio.h | 32 ++++++
> 4 files changed, 260 insertions(+), 0 deletions(-)
> create mode 100644 drivers/pps/clients/pps-gpio.c
> create mode 100644 include/linux/pps-gpio.h
>
> diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
> index 8520a7f..c2e0f1e 100644
> --- a/drivers/pps/clients/Kconfig
> +++ b/drivers/pps/clients/Kconfig
> @@ -29,4 +29,13 @@ 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_GPIO
> + tristate "PPS client using GPIO"
> + depends on PPS
> + help
> + If you say yes here you get support for a PPS source using
> + GPIO. To be useful you must also register a platform device
> + specifying the GPIO pin and other options, usually in your board
> + setup.
> +
> endif
> diff --git a/drivers/pps/clients/Makefile b/drivers/pps/clients/Makefile
> index 4feb7e9..a461d15 100644
> --- a/drivers/pps/clients/Makefile
> +++ b/drivers/pps/clients/Makefile
> @@ -5,5 +5,6 @@
> 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_GPIO) += pps-gpio.o
>
> ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG
> diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
> new file mode 100644
> index 0000000..fe9d913
> --- /dev/null
> +++ b/drivers/pps/clients/pps-gpio.c
> @@ -0,0 +1,218 @@
> +/*
> + * pps-gpio.c -- PPS client driver using GPIO
> + *
> + *
> + * Copyright (C) 2010 Ricardo Martins <rasm@xxxxxxxx>
> + * Copyright (C) 2011 James Nuss <jamesnuss@xxxxxxxxxxxxxx>
> + *
> + * 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.
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#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/pps-gpio.h>
> +#include <linux/gpio.h>
> +#include <linux/list.h>
> +
> +#define PPS_GPIO_NAME "pps-gpio"
> +#define PPS_GPIO_VERSION "1.0.0"
> +
> +/* Info for each registered platform device */
> +struct pps_gpio_device_data {
> + int irq; /* IRQ used as PPS source */
> + struct pps_device *pps; /* PPS source device */
> + struct pps_source_info info; /* PPS source information */
> + const struct pps_gpio_platform_data *pdata;
> +};
> +
> +/*
> + * Report the PPS event
> + */
> +
> +static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
> +{
> + const struct pps_gpio_device_data *info;
> + struct pps_event_time ts;
> + int rising_edge;
> +
> + /* Get the time stamp first */
> + pps_get_ts(&ts);
> +
> + info = (const struct pps_gpio_device_data *)data;
> +
> + rising_edge = gpio_get_value(info->pdata->gpio_pin);
> + if ((rising_edge && !info->pdata->assert_falling_edge) ||
> + (!rising_edge && info->pdata->assert_falling_edge))
> + pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
> + else if (info->pdata->capture_clear &&
> + ((rising_edge && info->pdata->assert_falling_edge) ||
> + (!rising_edge && !info->pdata->assert_falling_edge)))
> + pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int pps_gpio_setup(struct platform_device *pdev)
> +{
> + int ret;
> + const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
> +
> + ret = gpio_request(pdata->gpio_pin, pdata->gpio_label);
> + if (ret) {
> + pr_warning("failed to request GPIO %u\n", pdata->gpio_pin);
> + return -1;
> + }
> +
> + ret = gpio_direction_input(pdata->gpio_pin);
> + if (ret) {
> + pr_warning("failed to set pin direction\n");
> + return -1;

I think you should release the requested GPIO above before
returning...

> + }
> +
> + return 0;
> +}
> +
> +static unsigned long
> +get_irqf_trigger_flags(const struct pps_gpio_platform_data *pdata)
> +{
> + unsigned long flags = pdata->assert_falling_edge ?
> + IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
> +
> + if (pdata->capture_clear) {
> + flags |= ((flags & IRQF_TRIGGER_RISING) ?
> + IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
> + }
> +
> + return flags;
> +}
> +
> +static int pps_gpio_probe(struct platform_device *pdev)
> +{
> + struct pps_gpio_device_data *data;
> + int irq;
> + int ret;
> + int pps_default_params;
> + const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
> +
> +
> + /* GPIO setup */
> + ret = pps_gpio_setup(pdev);
> + if (ret)
> + return -EINVAL;
> +
> + /* IRQ setup */
> + irq = gpio_to_irq(pdata->gpio_pin);
> + if (irq < 0) {
> + pr_err("failed to map GPIO to IRQ: %d\n", irq);
> + return -EINVAL;
> + }
> +
> + /* allocate space for device info */
> + data = kzalloc(sizeof(struct pps_gpio_device_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;
> + if (pdata->capture_clear)
> + data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
> + PPS_ECHOCLEAR;
> + data->info.owner = THIS_MODULE;
> + snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
> + pdev->name, pdev->id);
> +
> + /* register PPS source */
> + pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
> + if (pdata->capture_clear)
> + pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
> + data->pps = pps_register_source(&data->info, pps_default_params);
> + if (data->pps == NULL) {
> + kfree(data);
> + pr_err("failed to register IRQ %d as PPS source\n", irq);
> + return -EINVAL;
> + }
> +
> + data->irq = irq;
> + data->pdata = pdata;
> +
> + /* register IRQ interrupt handler */
> + ret = request_irq(irq, pps_gpio_irq_handler,
> + get_irqf_trigger_flags(pdata), data->info.name, data);
> + if (ret) {
> + pps_unregister_source(data->pps);
> + kfree(data);
> + pr_err("failed to acquire IRQ %d\n", irq);
> + return -EINVAL;
> + }
> +
> + platform_set_drvdata(pdev, data);
> + dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n", irq);
> +
> + return 0;
> +}
> +
> +static int pps_gpio_remove(struct platform_device *pdev)
> +{
> + struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
> + const struct pps_gpio_platform_data *pdata = data->pdata;
> +
> + platform_set_drvdata(pdev, NULL);
> + free_irq(data->irq, data);
> + gpio_free(pdata->gpio_pin);
> + pps_unregister_source(data->pps);
> + pr_info("removed IRQ %d as PPS source\n", data->irq);
> + kfree(data);
> + return 0;
> +}
> +
> +static struct platform_driver pps_gpio_driver = {
> + .probe = pps_gpio_probe,
> + .remove = __devexit_p(pps_gpio_remove),
> + .driver = {
> + .name = PPS_GPIO_NAME,
> + .owner = THIS_MODULE
> + },
> +};
> +
> +static int __init pps_gpio_init(void)
> +{
> + int ret = platform_driver_register(&pps_gpio_driver);
> + if (ret < 0)
> + pr_err("failed to register platform driver\n");
> + return ret;
> +}
> +
> +static void __exit pps_gpio_exit(void)
> +{
> + platform_driver_unregister(&pps_gpio_driver);
> + pr_debug("unregistered platform driver\n");
> +}
> +
> +module_init(pps_gpio_init);
> +module_exit(pps_gpio_exit);
> +
> +MODULE_AUTHOR("Ricardo Martins <rasm@xxxxxxxx>");
> +MODULE_AUTHOR("James Nuss <jamesnuss@xxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Use GPIO pin as PPS source");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION(PPS_GPIO_VERSION);
> diff --git a/include/linux/pps-gpio.h b/include/linux/pps-gpio.h
> new file mode 100644
> index 0000000..0035abe
> --- /dev/null
> +++ b/include/linux/pps-gpio.h
> @@ -0,0 +1,32 @@
> +/*
> + * pps-gpio.h -- PPS client for GPIOs
> + *
> + *
> + * Copyright (C) 2011 James Nuss <jamesnuss@xxxxxxxxxxxxxx>
> + *
> + * 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.
> + */
> +
> +#ifndef _PPS_GPIO_H
> +#define _PPS_GPIO_H
> +
> +struct pps_gpio_platform_data {
> + bool assert_falling_edge;
> + bool capture_clear;
> + unsigned int gpio_pin;
> + const char *gpio_label;
> +};
> +
> +#endif
> --
> 1.7.1

It's ok for me. Fix the above error and resubmit.

Ciao,

Rodolfo

--

GNU/Linux Solutions e-mail: giometti@xxxxxxxxxxxx
Linux Device Driver giometti@xxxxxxxx
Embedded Systems phone: +39 349 2432127
UNIX programming skype: rodolfo.giometti
Freelance ICT Italia - Consulente ICT Italia - www.consulenti-ict.it
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: Ankita Garg: "[PATCH 2/5] memref module to walk the process page table"
Previous message: Florian Mickler: "Re: [PATCH] ACPI: Fix lockdep false positives in acpi_power_off()"
In reply to: James Nuss: "[PATCH v2 2/2] pps: new client driver using GPIO"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]