--- /dev/null
+/*
+ * gpio_test.c - GPIO test driver
+ *
+ * Copyright (C) 2008 Peter Henn
+ *
+ * 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.
+ *
+ * It just triggers a specified GPIO line setup the output
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+
+
+//*****************************************************************************
+// MODULE PARAMETERS
+//*****************************************************************************
+#define DRVNAME "gpio_test" /* name of the driver */
+#define DRIVER_VERSION "0.1" /* helps identifing different versions of that driver */
+#define LABEL NULL
+
+static unsigned int gpi;
+static unsigned int gpo;
+static unsigned int val;
+static unsigned int irq = -1;
+
+typedef struct {
+ int out_cansleep;
+ int in_cansleep;
+ int irq;
+ int cnt;
+} gpio_t_struct;
+
+static gpio_t_struct gt;
+
+static irqreturn_t gpio_test_irq_handler(int irq, void *dev_id)
+{
+
+ // todo use dev_id to get pointer to own driver structure data;
+ // container can be memory init with GPK_KERNEL
+ if (irq == gt.irq) {
+ gt.cnt++;
+ val = !val;
+ if (!gt.in_cansleep) {
+ pr_info("%s: GPIO #%d in value %d with counter %d\n", DRVNAME, gpi, gpio_get_value(gpi), gt.cnt);
+ }
+ if (!gt.out_cansleep) {
+ gpio_set_value(gpo, !val);
+ }
+ }
+ return IRQ_HANDLED;
+}
+
+/*
+** just set here the value
+*/
+static int __init gpio_test_init(void)
+{
+ int err;
+ err = gpio_is_valid(gpo);
+ if (err<0) {
+ pr_err("%s: GPIO #%d for output is not usable\n", DRVNAME, gpo);
+ return err;
+ }
+ //ToDo: Test, how a text might be used as LABEL
+ err = gpio_request(gpo, LABEL);
+ if (err<0) {
+ pr_err("%s: GPIO #%d for output is can not be requested\n", DRVNAME, gpo);
+ return err;
+ }
+ gt.out_cansleep = gpio_cansleep(gpo);
+ pr_info("%s: GPIO #%d for output %s sleep\n", DRVNAME, gpo, ((gt.out_cansleep>0) ? "can" : "will not"));
+ err = gpio_direction_output(gpo, val);
+ if (err<0) {
+ pr_err("%s: GPIO #%d output direction is not possible\n", DRVNAME, gpo);
+ gpio_free(gpo);
+ return err;
+ }
+
+ err = gpio_is_valid(gpi);
+ if (err<0) {
+ pr_err("%s: GPIO #%d for inout is not usable\n", DRVNAME, gpi);
+ gpio_free(gpo);
+ return err;
+ }
+ err = gpio_request(gpi, LABEL);
+ if (err<0) {
+ pr_err("%s: GPIO #%d for input is can not be requested\n", DRVNAME, gpi);
+ gpio_free(gpo);
+ return err;
+ }
+ gt.in_cansleep = gpio_cansleep(gpi);
+ pr_info("%s: GPIO #%d for input %s sleep\n", DRVNAME, gpi, ((gt.in_cansleep>0) ? "can" : "will not"));
+ gt.irq = gpio_to_irq(gpi);
+ if (gt.irq<0) {
+ pr_info("%s: GPIO #%d IRQ is not supported\n", DRVNAME, gpi);
+ gt.irq = irq;
+ if (gt.irq >= 0) {
+ pr_info("%s: we force interrupt to IRQ %d\n", DRVNAME, gt.irq);
+ }
+ } else {
+ pr_info("%s: GPIO #%d IRQ %d is supported\n", DRVNAME, gpi, gt.irq);
+ }
+ /* gpio_direction_output must be call from task context, we use insmod as task context here */
+ err = gpio_direction_input(gpi);
+ if (err<0) {
+ pr_err("%s: GPIO #%d input direction is not possible\n", DRVNAME, gpi);
+ gpio_free(gpo);
+ gpio_free(gpi);
+ return err;
+ }
+ gt.cnt=0;
+ /* register irq handler */
+ // ToDo: Test with other flag types: IRQF_SHARED, IRQF_TRIGGER_*
+ if (gt.irq >= 0) {
+ err = request_irq(gt.irq, gpio_test_irq_handler, IRQF_TRIGGER_NONE, "gpio_test_handler", NULL);
+ if (err<0) {
+ pr_err("%s: GPIO #%d IRQ %d can not be requested, got %d\n", DRVNAME, gpi, gt.irq, err);
+ gt.irq = -1;
+ }
+ }
+ return 0;
+}
+
+device_initcall(gpio_test_init);
+
+/*
+** just restore here the old value
+*/
+static void __exit gpio_test_exit(void)
+{
+ if (gt.out_cansleep) {
+ gpio_set_value_cansleep(gpo, !val);
+ } else {
+ gpio_set_value(gpo, !val);
+ }
+ if (gt.irq >= 0) free_irq(gt.irq, NULL);
+ gpio_free(gpo);
+ gpio_free(gpi);
+}
+module_exit(gpio_test_exit);
+
+module_param(gpo, uint, S_IRUGO);
+MODULE_PARM_DESC(gpo, "GPIO output address or number");
+
+module_param(gpi, uint, S_IRUGO);
+MODULE_PARM_DESC(gpi, "GPIO input address or number");
+
+module_param(val, bool, S_IRUGO);
+MODULE_PARM_DESC(val, "GPIO output value 0 or 1");
+
+module_param(irq, uint, S_IRUGO);
+MODULE_PARM_DESC(irq, "GPIO interrupt number");
+
+
+MODULE_AUTHOR("Option Wireless");
+MODULE_DESCRIPTION("GPIO output test");
+MODULE_LICENSE("GPL");
+
+MODULE_INFO(Version, DRIVER_VERSION);
projects / pub / spi-gpio-pp.git / blobdiff