IIO: ADC: New driver for the AD7298 8-channel SPI ADC
This patch adds support for the
AD7298: 8-Channel, 1MSPS, 12-Bit SAR ADC with Temperature Sensor
via SPI bus.
This patch replaces the existing ad7298.c driver completely.
It was necessary since, the old driver did not comply with the
IIO ABI for such devices.
Changes since V1:
IIO: ADC: New driver for the AD7298 8-channel SPI ADC
Add documentation for new sysfs file tempX_input.
Simplify bit defines.
Remove outdated comments.
Fix indention style.
ad7298_show_temp():
Add locking.
Simplify temperature calculation.
Change temperature result from degrees into milli degrees Celsius.
Rename file according to new sysfs ABI documentation
Add timestamp attributes.
Revise timestamp handling accordingly.
Preset timestamp generation.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Reviewed-by: Shubhrajyoti <Shubhrajyoti@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/iio/adc/ad7298_core.c b/drivers/staging/iio/adc/ad7298_core.c
new file mode 100644
index 0000000..2e9154e
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7298_core.c
@@ -0,0 +1,287 @@
+/*
+ * AD7298 SPI ADC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/spi/spi.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../ring_generic.h"
+#include "adc.h"
+
+#include "ad7298.h"
+
+static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
+{
+ int ret;
+ st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
+ (AD7298_CH(0) >> ch));
+
+ ret = spi_sync(st->spi, &st->scan_single_msg);
+ if (ret)
+ return ret;
+
+ return be16_to_cpu(st->rx_buf[0]);
+}
+
+static ssize_t ad7298_scan(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7298_state *st = dev_info->dev_data;
+ struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+ int ret;
+
+ mutex_lock(&dev_info->mlock);
+ if (iio_ring_enabled(dev_info))
+ ret = ad7298_scan_from_ring(st, this_attr->address);
+ else
+ ret = ad7298_scan_direct(st, this_attr->address);
+ mutex_unlock(&dev_info->mlock);
+
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", ret & RES_MASK(AD7298_BITS));
+}
+
+static IIO_DEV_ATTR_IN_RAW(0, ad7298_scan, 0);
+static IIO_DEV_ATTR_IN_RAW(1, ad7298_scan, 1);
+static IIO_DEV_ATTR_IN_RAW(2, ad7298_scan, 2);
+static IIO_DEV_ATTR_IN_RAW(3, ad7298_scan, 3);
+static IIO_DEV_ATTR_IN_RAW(4, ad7298_scan, 4);
+static IIO_DEV_ATTR_IN_RAW(5, ad7298_scan, 5);
+static IIO_DEV_ATTR_IN_RAW(6, ad7298_scan, 6);
+static IIO_DEV_ATTR_IN_RAW(7, ad7298_scan, 7);
+
+static ssize_t ad7298_show_temp(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7298_state *st = iio_dev_get_devdata(dev_info);
+ int tmp;
+
+ tmp = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
+ AD7298_TAVG | st->ext_ref);
+
+ mutex_lock(&dev_info->mlock);
+ spi_write(st->spi, (u8 *)&tmp, 2);
+ tmp = 0;
+ spi_write(st->spi, (u8 *)&tmp, 2);
+ usleep_range(101, 1000); /* sleep > 100us */
+ spi_read(st->spi, (u8 *)&tmp, 2);
+ mutex_unlock(&dev_info->mlock);
+
+ tmp = be16_to_cpu(tmp) & RES_MASK(AD7298_BITS);
+
+ /*
+ * One LSB of the ADC corresponds to 0.25 deg C.
+ * The temperature reading is in 12-bit twos complement format
+ */
+
+ if (tmp & (1 << (AD7298_BITS - 1))) {
+ tmp = (4096 - tmp) * 250;
+ tmp -= (2 * tmp);
+
+ } else {
+ tmp *= 250; /* temperature in milli degrees Celsius */
+ }
+
+ return sprintf(buf, "%d\n", tmp);
+}
+
+static IIO_DEVICE_ATTR(temp0_input, S_IRUGO, ad7298_show_temp, NULL, 0);
+
+static ssize_t ad7298_show_scale(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7298_state *st = iio_dev_get_devdata(dev_info);
+ /* Corresponds to Vref / 2^(bits) */
+ unsigned int scale_uv = (st->int_vref_mv * 1000) >> AD7298_BITS;
+
+ return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
+}
+static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7298_show_scale, NULL, 0);
+
+static ssize_t ad7298_show_name(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7298_state *st = iio_dev_get_devdata(dev_info);
+
+ return sprintf(buf, "%s\n", spi_get_device_id(st->spi)->name);
+}
+static IIO_DEVICE_ATTR(name, S_IRUGO, ad7298_show_name, NULL, 0);
+
+static struct attribute *ad7298_attributes[] = {
+ &iio_dev_attr_in0_raw.dev_attr.attr,
+ &iio_dev_attr_in1_raw.dev_attr.attr,
+ &iio_dev_attr_in2_raw.dev_attr.attr,
+ &iio_dev_attr_in3_raw.dev_attr.attr,
+ &iio_dev_attr_in4_raw.dev_attr.attr,
+ &iio_dev_attr_in5_raw.dev_attr.attr,
+ &iio_dev_attr_in6_raw.dev_attr.attr,
+ &iio_dev_attr_in7_raw.dev_attr.attr,
+ &iio_dev_attr_in_scale.dev_attr.attr,
+ &iio_dev_attr_temp0_input.dev_attr.attr,
+ &iio_dev_attr_name.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group ad7298_attribute_group = {
+ .attrs = ad7298_attributes,
+};
+
+static int __devinit ad7298_probe(struct spi_device *spi)
+{
+ struct ad7298_platform_data *pdata = spi->dev.platform_data;
+ struct ad7298_state *st;
+ int ret;
+
+ st = kzalloc(sizeof(*st), GFP_KERNEL);
+ if (st == NULL) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+
+ st->reg = regulator_get(&spi->dev, "vcc");
+ if (!IS_ERR(st->reg)) {
+ ret = regulator_enable(st->reg);
+ if (ret)
+ goto error_put_reg;
+ }
+
+ spi_set_drvdata(spi, st);
+
+ atomic_set(&st->protect_ring, 0);
+ st->spi = spi;
+
+ st->indio_dev = iio_allocate_device();
+ if (st->indio_dev == NULL) {
+ ret = -ENOMEM;
+ goto error_disable_reg;
+ }
+
+ st->indio_dev->dev.parent = &spi->dev;
+ st->indio_dev->attrs = &ad7298_attribute_group;
+ st->indio_dev->dev_data = (void *)(st);
+ st->indio_dev->driver_module = THIS_MODULE;
+ st->indio_dev->modes = INDIO_DIRECT_MODE;
+
+ /* Setup default message */
+
+ st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
+ st->scan_single_xfer[0].len = 2;
+ st->scan_single_xfer[0].cs_change = 1;
+ st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
+ st->scan_single_xfer[1].len = 2;
+ st->scan_single_xfer[1].cs_change = 1;
+ st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
+ st->scan_single_xfer[2].len = 2;
+
+ spi_message_init(&st->scan_single_msg);
+ spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
+ spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
+ spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
+
+ if (pdata && pdata->vref_mv) {
+ st->int_vref_mv = pdata->vref_mv;
+ st->ext_ref = AD7298_EXTREF;
+ } else {
+ st->int_vref_mv = AD7298_INTREF_mV;
+ }
+
+ ret = ad7298_register_ring_funcs_and_init(st->indio_dev);
+ if (ret)
+ goto error_free_device;
+
+ ret = iio_device_register(st->indio_dev);
+ if (ret)
+ goto error_free_device;
+
+ ret = iio_ring_buffer_register(st->indio_dev->ring, 0);
+ if (ret)
+ goto error_cleanup_ring;
+ return 0;
+
+error_cleanup_ring:
+ ad7298_ring_cleanup(st->indio_dev);
+ iio_device_unregister(st->indio_dev);
+error_free_device:
+ iio_free_device(st->indio_dev);
+error_disable_reg:
+ if (!IS_ERR(st->reg))
+ regulator_disable(st->reg);
+error_put_reg:
+ if (!IS_ERR(st->reg))
+ regulator_put(st->reg);
+ kfree(st);
+error_ret:
+ return ret;
+}
+
+static int __devexit ad7298_remove(struct spi_device *spi)
+{
+ struct ad7298_state *st = spi_get_drvdata(spi);
+ struct iio_dev *indio_dev = st->indio_dev;
+
+ iio_ring_buffer_unregister(indio_dev->ring);
+ ad7298_ring_cleanup(indio_dev);
+ iio_device_unregister(indio_dev);
+ if (!IS_ERR(st->reg)) {
+ regulator_disable(st->reg);
+ regulator_put(st->reg);
+ }
+ kfree(st);
+ return 0;
+}
+
+static const struct spi_device_id ad7298_id[] = {
+ {"ad7298", 0},
+ {}
+};
+
+static struct spi_driver ad7298_driver = {
+ .driver = {
+ .name = "ad7298",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = ad7298_probe,
+ .remove = __devexit_p(ad7298_remove),
+ .id_table = ad7298_id,
+};
+
+static int __init ad7298_init(void)
+{
+ return spi_register_driver(&ad7298_driver);
+}
+module_init(ad7298_init);
+
+static void __exit ad7298_exit(void)
+{
+ spi_unregister_driver(&ad7298_driver);
+}
+module_exit(ad7298_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("spi:ad7298");