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Commit 9d24e336 authored by Federico Vaga's avatar Federico Vaga
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drivers/zio-ad7888.c: new driver for AD7888 ADC 

Signed-off-by: 's avatarFederico Vaga <federico.vaga@gmail.com>
Acked-by: Alessandro Rubini's avatarAlessandro Rubini <rubini@gnudd.com>
parent 6f8f0bb5
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drivers/Makefile
View file @ 9d24e336
LINUX ?= /lib/modules/$(shell uname -r)/build
EXTRA_CFLAGS += -I$(obj)/../include/
EXTRA_CFLAGS += -I$(obj)/../include/ -DDEBUG
obj-m = zio-zero.o
obj-m += zio-gpio.o
obj-m += zio-ad7888.o
all:
$(MAKE) -C $(LINUX) M=$(shell /bin/pwd) modules
drivers/zio-ad7888.c 0 → 100644
View file @ 9d24e336
/* Federico Vaga for CERN, 2011, GNU GPLv2 or later */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spi/spi.h>
#include <linux/fs.h>
#include <linux/zio.h>
#include <linux/zio-sysfs.h>
#include <linux/zio-buffer.h>
#include <linux/zio-trigger.h>
enum ad7888_driver_supported_device {
ID_AD7888
};
ZIO_PARAM_TRIGGER(ad7888_trigger);
ZIO_PARAM_BUFFER(ad7888_buffer);
struct ad7888_context {
struct spi_message message;
struct spi_transfer transfer;
struct zio_cset *cset;
};
struct ad7888_private {
struct spi_device *spi;
uint16_t cmd;
};
struct ad7888_private *ad7888_prv;
/*
* AD7888 doesn't have register to store data configuration; configuration
* option are sent every time when we want acquire. So, there is no address
* register to set but only a value. Address is used as mask in the tx_buf.
*/
DEFINE_ZATTR_STD(ZDEV, zattr_dev) = {
ZATTR_REG(zdev, ZATTR_NBIT, S_IRUGO, 0, 12),
/* vref_src can be internal (0) or external (1)*/
ZATTR_REG(zdev, ZATTR_VREFTYPE, S_IRUGO | S_IWUGO, 0x40, 0),
};
struct zio_attribute zattr_dev_ext[] = {
ZATTR_EXT_REG("power_managment", S_IRUGO | S_IWUGO, 0x30, 0x0),
};
int ad7888_conf_set(struct kobject *kobj, struct zio_attribute *zattr,
uint32_t usr_val)
{
unsigned long mask = zattr->priv.addr;
pr_debug("%s:%d", __func__, __LINE__);
switch (mask) {
case 0x30: /* power management */
if (usr_val & ~mask)
return -EINVAL;
ad7888_prv->cmd = (ad7888_prv->cmd & ~mask) | usr_val;
break;
case 0x40: /* v_ref source */
if (usr_val > 1) /* single bit: 0 or 1*/
return -EINVAL;
ad7888_prv->cmd = (ad7888_prv->cmd & ~mask) |
(usr_val << (mask - 2));
}
zattr->value = usr_val;
return 0;
}
/* read from AD7888 and return the pointer to the data */
static void ad7888_complete(void *cont)
{
struct ad7888_context *context = (struct ad7888_context *) cont;
struct zio_cset *cset ;
uint16_t *data, *buf;
int i, j;
cset = context->cset;
data = (uint16_t *) context->transfer.rx_buf;
data = &data[1];
/* demux data */
/*FIXME this loop is bugged, sometimes it doesn't work */
for (j = 0; j < cset->n_chan; ++j) {
buf = (uint16_t *)cset->chan[j].active_block->data;
for (i = 0; i < cset->ti->current_ctrl->nsamples; ++i)
buf[i] = data[i * cset->n_chan + j];
}
cset->ti->t_op->data_done(cset);
/* free context */
kfree(context->transfer.tx_buf);
kfree(context->transfer.rx_buf);
kfree(context);
}
int ad7888_input_cset(struct zio_cset *cset)
{
int i, j, k, err = -EBUSY;
struct ad7888_context *context;
uint16_t *command;
uint32_t size;
/* alloc context */
context = kzalloc(sizeof(struct ad7888_context), GFP_ATOMIC);
if (!context)
return -ENOMEM;
/* prepare SPI message and transfer */
size = (cset->n_chan * cset->ti->current_ctrl->nsamples * 2) + 2;
context->transfer.tx_buf = kmalloc(size, GFP_ATOMIC);
context->transfer.rx_buf = kmalloc(size, GFP_ATOMIC);
if (!context->transfer.tx_buf || !context->transfer.rx_buf) {
kfree(context->transfer.tx_buf);
kfree(context->transfer.rx_buf);
return -ENOMEM;
}
context->transfer.len = size;
/* configure transfer buffer*/
command = (uint16_t *)context->transfer.tx_buf;
for (i = 0, k = 0; i < cset->ti->current_ctrl->nsamples; ++i)
for (j = 0; j < cset->n_chan; ++j, ++k)
command[k] = (j << 11) | ad7888_prv->cmd;
command[k] = ad7888_prv->cmd;
spi_message_init(&context->message);
context->message.complete = ad7888_complete;
context->message.context = context;
context->cset = cset;
spi_message_add_tail(&context->transfer, &context->message);
/* start acquisition */
err = spi_async_locked(ad7888_prv->spi, &context->message);
if (!err)
return -EAGAIN;
kfree(context->transfer.tx_buf);
kfree(context->transfer.rx_buf);
kfree(context);
return err;
}
struct zio_sysfs_operations ad7888_s_op = {
.conf_set = ad7888_conf_set,
};
struct zio_device_operations ad7888_d_op = {
.input_cset = ad7888_input_cset,
};
/* channel sets available */
static struct zio_cset ad7888_ain_cset[] = {
{
.ssize = 2,
.n_chan = 8,
.flags = ZCSET_TYPE_ANALOG | /* is analog */
ZIO_DIR_INPUT /* is input */,
},
};
struct zio_device zdev_ad7888 = {
.owner = THIS_MODULE,
.s_op = &ad7888_s_op,
.d_op = &ad7888_d_op,
.flags = 0,
.cset = ad7888_ain_cset,
.n_cset = ARRAY_SIZE(ad7888_ain_cset),
.zattr_set = {
.std_zattr = zattr_dev,
.ext_zattr = zattr_dev_ext,
.n_ext_attr = ARRAY_SIZE(zattr_dev_ext),
},
};
static int __devinit ad7888_probe(struct spi_device *spi)
{
int err;
ad7888_prv = kmalloc(sizeof(struct ad7888_private), GFP_KERNEL);
ad7888_prv->spi = spi;
spi_set_drvdata(spi, &zdev_ad7888);
spi->bits_per_word = 16;
err = spi_setup(spi);
if (err)
return err;
ad7888_prv->cmd = zattr_dev[ZATTR_VREFTYPE].value << 6 |
zattr_dev_ext[0].value << 0;
if (ad7888_trigger)
zdev_ad7888.preferred_trigger = ad7888_trigger;
if (ad7888_buffer)
zdev_ad7888.preferred_buffer = ad7888_buffer;
err = zio_register_dev(&zdev_ad7888, "ad7888");
if (err)
kfree(ad7888_prv);
return err;
}
static int __devexit ad7888_remove(struct spi_device *spi)
{
zio_unregister_dev(&zdev_ad7888);
kfree(ad7888_prv);
return 0;
}
static const struct spi_device_id ad7888_id[] = {
{"ad7888", ID_AD7888},
{}
};
static struct spi_driver ad7888_driver = {
.driver = {
.name = "ad7888",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.id_table = ad7888_id,
.probe = ad7888_probe,
.remove = __devexit_p(ad7888_remove),
};
static int __init ad7888_init(void)
{
return spi_register_driver(&ad7888_driver);
}
static void __exit ad7888_exit(void)
{
driver_unregister(&ad7888_driver.driver);
}
module_init(ad7888_init);
module_exit(ad7888_exit);
MODULE_AUTHOR("Federico Vaga <federico.vaga@gmail.com>");
MODULE_DESCRIPTION("AD7888 driver for ZIO framework");
MODULE_LICENSE("GPL");
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