new trigger: zio-trigger-irq

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com>

triggers/Makefile

@@ -3,6 +3,7 @@ LINUX ?= /lib/modules/$(shell uname -r)/build
 EXTRA_CFLAGS += -I$(obj)/../include/
 
 obj-m = zio-trig-timer.o
+obj-m += zio-trig-irq.o
 
 all:
 	$(MAKE) -C $(LINUX) M=$(shell /bin/pwd) modules

triggers/zio-trig-irq.c

+/* Alessandro Rubini for CERN, 2011, GNU GPLv2 or later */
+
+/*
+ * This is a trigger based on an external IRQ. You can specify the IRQ
+ * number or the GPIO number -- then the associated IRQ is used
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+
+#include <linux/zio.h>
+#include <linux/zio-sysfs.h>
+#include <linux/zio-buffer.h>
+#include <linux/zio-trigger.h>
+
+static int zti_irq = -1;
+static int zti_gpio = -1;
+module_param_named(irq, zti_irq, int, 0444);
+module_param_named(gpio, zti_gpio, int, 0444);
+
+enum zti_attrs {
+	ZTI_ATTR_NSAMPLES = 0,
+	ZTI_ATTR_IRQ,
+	ZTI_ATTR_GPIO,
+};
+
+static DEFINE_ZATTR_STD(TRIG, zti_std_attr) = {
+	ZATTR_REG(trig, ZATTR_TRIG_NSAMPLES, S_IRUGO | S_IWUGO,
+		  ZTI_ATTR_NSAMPLES, 16),
+};
+
+static struct zio_attribute zti_ext_attr[] = {
+	ZATTR_EXT_REG("irq", S_IRUGO, ZTI_ATTR_IRQ, -1),
+	ZATTR_EXT_REG("gpio", S_IRUGO, ZTI_ATTR_GPIO, -1),
+};
+int zti_conf_set (struct kobject *kobj, struct zio_attribute *zattr,
+		uint32_t  usr_val)
+{
+	struct zio_ti *ti = to_zio_ti(kobj);
+
+	pr_debug("%s:%d\n", __func__, __LINE__);
+	zattr->value = usr_val;
+	switch (zattr->priv.addr) {
+	case ZTI_ATTR_NSAMPLES:
+		ti->current_ctrl->nsamples = usr_val;
+		break;
+	/* other attributes are read-only */
+	default:
+		pr_err("%s: unknown \"addr\" for configuration\n", __func__);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+struct zio_sys_operations zti_s_ops = {
+	.conf_set = zti_conf_set,
+};
+
+irqreturn_t zti_handler(int irq, void *dev_id)
+{
+	struct zio_ti *ti = dev_id;
+
+	/* When a trigger fires, we must prepare our control and timestamp */
+	getnstimeofday(&ti->tstamp);
+	zio_fire_trigger(ti);
+	return IRQ_HANDLED;
+}
+
+/*
+ * The trigger operations are the core of a trigger type
+ */
+static int zti_push_block(struct zio_ti *ti, struct zio_channel *chan,
+			  struct zio_block *block)
+{
+	/* software triggers must store pending stuff in chan->t_priv */
+	pr_debug("%s:%d\n", __func__, __LINE__);
+
+	if (chan->t_priv)
+		return -EBUSY;
+	chan->t_priv = block;
+	return 0;
+}
+
+static int zti_config(struct zio_ti *ti, struct zio_control *ctrl)
+{
+	/* FIXME: config is not supported yet */
+
+	pr_debug("%s:%d\n", __func__, __LINE__);
+	return 0;
+}
+
+static struct zio_ti *zti_create(struct zio_trigger_type *trig,
+				 struct zio_cset *cset,
+				 struct zio_control *ctrl, fmode_t flags)
+{
+	struct zio_ti *ti;
+
+	int ret;
+	pr_debug("%s:%d\n", __func__, __LINE__);
+
+	ti = kzalloc(sizeof(*ti), GFP_KERNEL);
+	if (!ti)
+		return ERR_PTR(-ENOMEM);
+
+	/* The current control is already filled: just set nsamples */
+	ctrl->nsamples = zti_std_attr[ZATTR_TRIG_NSAMPLES].value;
+	ti->current_ctrl = ctrl;
+
+	ret = request_irq(zti_irq, zti_handler, IRQF_SHARED
+			  | IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+			  KBUILD_MODNAME, ti);
+	if (ret < 0) {
+		kfree(ti);
+		return ERR_PTR(ret);
+	}
+	return ti;
+}
+
+static void zti_destroy(struct zio_ti *ti)
+{
+	pr_debug("%s:%d\n", __func__, __LINE__);
+	free_irq(zti_irq, &ti);
+	kfree(ti);
+}
+
+static const struct zio_trigger_operations zti_trigger_ops = {
+	.push_block = zti_push_block,
+	.pull_block = NULL,
+	.data_done = zio_generic_data_done,
+	.config = zti_config,
+	.create = zti_create,
+	.destroy = zti_destroy,
+};
+
+static struct zio_trigger_type zti_trigger = {
+	.owner = THIS_MODULE,
+	.zattr_set = {
+		.std_zattr = zti_std_attr,
+		.ext_zattr = zti_ext_attr,
+		.n_ext_attr = ARRAY_SIZE(zti_ext_attr),
+	},
+	.s_op = &zti_s_ops,
+	.t_op = &zti_trigger_ops,
+	.f_op = NULL, /* we use buffer fops */
+};
+
+/*
+ * A validation function, called at insmod and at parameter change
+ */
+static int zti_validate(int irq, int gpio)
+{
+	int ret = 0;
+
+	if (irq != -1 && gpio != -1) {
+		pr_err("%s: only set irq or gpio, not both\n", KBUILD_MODNAME);
+		return -EINVAL;
+	}
+	if (irq == -1 && gpio == -1) {
+		pr_err("%s: please set irq or gpio\n", KBUILD_MODNAME);
+		return -EINVAL;
+	}
+	if (gpio != -1) {
+		irq = gpio_to_irq(gpio);
+		if (irq >= 0) {
+			ret  = gpio_request(gpio, KBUILD_MODNAME);
+		} else {
+			ret = irq;
+		}
+	}
+	if (ret < 0) {
+		pr_err("%s: invalid irq/gpio (%i/%i)\n", KBUILD_MODNAME,
+		       gpio, irq);
+		return ret;
+	}
+	zti_irq = irq; /* used at trigger_create time */
+	return 0;
+}
+
+/*
+ * init and exit
+ */
+static int __init zti_init(void)
+{
+	int ret = zti_validate(zti_irq, zti_gpio);
+	if (ret)
+		return ret;
+	return zio_register_trig(&zti_trigger, "irq");
+}
+
+static void __exit zti_exit(void)
+{
+	zio_unregister_trig(&zti_trigger);
+	if (zti_gpio)
+		gpio_free(zti_gpio);
+}
+
+module_init(zti_init);
+module_exit(zti_exit);
+MODULE_AUTHOR("Alessandro Rubini");
+MODULE_LICENSE("GPL");