drivers: added zio-mini

zio-mini is a very simple driver, with no attributes, that can be used to get accustomed with how ZIO and the ZIO bus work. You can create as many devices as you want, with as many channels as you want. Each device has only one input cset, that returns the struct timespec collected at raw_io() time. The driver always returns one sample only, even if the trigger asks for more. Signed-off-by: Alessandro Rubini <rubini@gnudd.com> Acked-by: Federico Vaga <federico.vaga@gmail.com>

drivers: added zio-mini
zio-mini is a very simple driver, with no attributes, that can be used to get accustomed with how ZIO and the ZIO bus work. You can create as many devices as you want, with as many channels as you want. Each device has only one input cset, that returns the struct timespec collected at raw_io() time. The driver always returns one sample only, even if the trigger asks for more. Signed-off-by: Alessandro Rubini <rubini@gnudd.com> Acked-by: Federico Vaga <federico.vaga@gmail.com>
3ad30417 · Alessandro Rubini · Federico Vaga · 371ff973 · 3ad30417 · 3ad30417
Commit 3ad30417 authored Nov 05, 2012 by Alessandro Rubini Committed by Federico Vaga Nov 09, 2012
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Makefile drivers/Makefile +1 -0

zio-mini.c drivers/zio-mini.c +140 -0

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--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -4,6 +4,7 @@ EXTRA_CFLAGS += -I$(obj)/../include

 obj-m = zio-zero.o
 obj-m += zio-loop.o
+obj-m += zio-mini.o
 obj-m += zio-gpio.o
 ifdef CONFIG_SPI
 obj-m += zio-ad788x.o

--- a/drivers/zio-mini.c
+++ b/drivers/zio-mini.c
+/* Alessandro Rubini, 2012, public domain */
+
+/*
+ * A minimal device: one input channel only: returns an 8-byte sample
+ * with a native-endianness timespec
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+
+#include <linux/zio.h>
+#include <linux/zio-buffer.h>
+
+ZIO_PARAM_TRIGGER(zmini_trigger);
+ZIO_PARAM_BUFFER(zmini_buffer);
+
+static int zmini_ndev = 1;
+module_param_named(ndev, zmini_ndev, int, 0444);
+static int zmini_nchan = 1;
+module_param_named(nchan, zmini_nchan, int, 0444);
+
+static int zmini_input(struct zio_cset *cset)
+{
+	struct zio_channel *chan;
+	struct zio_block *block;
+	struct timespec *ts;
+
+	/* Return immediately: just fill the blocks */
+	chan_for_each(chan, cset) {
+		block = chan->active_block;
+		if (!block)
+			continue;
+		if (block->datalen < sizeof(*ts))
+			continue;
+		/* we are allowed to return less data than allocated */
+		chan->current_ctrl->nsamples = 1;
+		block->datalen = sizeof(struct timespec);
+		getnstimeofday(block->data);
+	}
+	return 0; /* Already done */
+}
+static struct zio_cset zmini_cset[] = {
+	{
+		ZIO_SET_OBJ_NAME("timespec-in"),
+		.raw_io =	zmini_input,
+		.flags =	ZIO_DIR_INPUT,
+		.n_chan =	1, /* changed at insmod */
+		.ssize =	sizeof(struct timespec),
+	},
+};
+
+static struct zio_device zmini_tmpl = {
+	.owner =		THIS_MODULE,
+	.cset =			zmini_cset,
+	.n_cset =		ARRAY_SIZE(zmini_cset),
+};
+
+/* The driver uses a table of templates */
+static const struct zio_device_id zmini_table[] = {
+	{"zmini", &zmini_tmpl},
+	{},
+};
+
+static struct zio_driver zmini_zdrv = {
+	.driver = {
+		.name = "zmini",
+		.owner = THIS_MODULE,
+	},
+	.id_table = zmini_table,
+};
+
+/* The device is registered in the bus: we can have several */
+static struct zio_device **zmini_dev_array;
+
+static int __init zmini_init(void)
+{
+	int err, i;
+	struct zio_device *zdev;
+
+	/* customize the driver and register it */
+	if (zmini_trigger)
+		zmini_tmpl.preferred_trigger = zmini_trigger;
+	if (zmini_buffer)
+		zmini_tmpl.preferred_buffer = zmini_buffer;
+	zmini_cset[0].n_chan = zmini_nchan;
+
+	err = zio_register_driver(&zmini_zdrv);
+	if (err)
+		return err;
+
+	/* allocate the devices and register them */
+	if (zmini_ndev < 0 || zmini_ndev > 1024) {
+		pr_err("%s: ndev is %i: out of range\n", KBUILD_MODNAME,
+		       zmini_ndev);
+		return -EINVAL;
+	}
+	zmini_dev_array = kzalloc(zmini_ndev *sizeof(*zdev), GFP_KERNEL);
+	for (i = 0; i < zmini_ndev; i++) {
+		zdev = zio_allocate_device();
+		if (IS_ERR(zdev)) {
+			err = PTR_ERR(zdev);
+			goto out;
+		}
+		zdev->owner = THIS_MODULE;
+		err = zio_register_device(zdev, "zmini", 0);
+		if (err) {
+			zio_free_device(zdev);
+			goto out;
+		}
+		zmini_dev_array[i] = zdev;
+	}
+	return 0;
+out:
+	for (i = 0; i < zmini_ndev && zmini_dev_array[i]; i++) {
+		zio_unregister_device(zmini_dev_array[i]);
+		zio_free_device(zmini_dev_array[i]);
+	}
+	zio_unregister_driver(&zmini_zdrv);
+	kfree(zmini_dev_array);
+	return err;
+}
+
+static void __exit zmini_exit(void)
+{
+	int i;
+
+	for (i = 0; i < zmini_ndev && zmini_dev_array[i]; i++) {
+		zio_unregister_device(zmini_dev_array[i]);
+		zio_free_device(zmini_dev_array[i]);
+	}
+	zio_unregister_driver(&zmini_zdrv);
+	kfree(zmini_dev_array);
+	return;
+}
+
+module_init(zmini_init);
+module_exit(zmini_exit);
+
+MODULE_LICENSE("GPL and additional rights");