[PATCH 266/510] staging: iio: adc: Enable driver support for ad7887 AD converter
Greg Kroah-Hartman
gregkh at suse.de
Mon Jan 10 20:39:50 UTC 2011
From: Michael Hennerich <michael.hennerich at analog.com>
Enable support for AD7887: SPI Micropower, 2-Channel, 125 kSPS, 12-Bit ADC
staging: iio: adc: Fix according to review feedback
Review feedback by Jonathan Cameron:
Combine statements.
Document struct members.
Remove redundant variable initialization.
Simplify multichannel scan from ring logic.
Fix coding style.
[v2]
staging: iio: adc: ad7887: Fix typos
Signed-off-by: Michael Hennerich <michael.hennerich at analog.com>
Acked-by: Jonathan Cameron <jic23 at cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
---
drivers/staging/iio/adc/Kconfig | 14 ++
drivers/staging/iio/adc/Makefile | 4 +
drivers/staging/iio/adc/ad7887.h | 105 +++++++++++
drivers/staging/iio/adc/ad7887_core.c | 305 +++++++++++++++++++++++++++++++++
drivers/staging/iio/adc/ad7887_ring.c | 266 ++++++++++++++++++++++++++++
5 files changed, 694 insertions(+), 0 deletions(-)
create mode 100644 drivers/staging/iio/adc/ad7887.h
create mode 100644 drivers/staging/iio/adc/ad7887_core.c
create mode 100644 drivers/staging/iio/adc/ad7887_ring.c
diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
index 9ca6565..86869cd 100644
--- a/drivers/staging/iio/adc/Kconfig
+++ b/drivers/staging/iio/adc/Kconfig
@@ -97,6 +97,20 @@ config AD7476
To compile this driver as a module, choose M here: the
module will be called ad7476.
+config AD7887
+ tristate "Analog Devices AD7887 ADC driver"
+ depends on SPI
+ select IIO_RING_BUFFER
+ select IIO_SW_RING
+ select IIO_TRIGGER
+ help
+ Say yes here to build support for Analog Devices
+ AD7887 SPI analog to digital convertor (ADC).
+ If unsure, say N (but it's safe to say "Y").
+
+ To compile this driver as a module, choose M here: the
+ module will be called ad7887.
+
config AD7745
tristate "Analog Devices AD7745, AD7746 AD7747 capacitive sensor driver"
depends on I2C
diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
index a7dce6b..6f231a2 100644
--- a/drivers/staging/iio/adc/Makefile
+++ b/drivers/staging/iio/adc/Makefile
@@ -15,6 +15,10 @@ ad7476-y := ad7476_core.o
ad7476-$(CONFIG_IIO_RING_BUFFER) += ad7476_ring.o
obj-$(CONFIG_AD7476) += ad7476.o
+ad7887-y := ad7887_core.o
+ad7887-$(CONFIG_IIO_RING_BUFFER) += ad7887_ring.o
+obj-$(CONFIG_AD7887) += ad7887.o
+
obj-$(CONFIG_AD7150) += ad7150.o
obj-$(CONFIG_AD7152) += ad7152.o
obj-$(CONFIG_AD7291) += ad7291.o
diff --git a/drivers/staging/iio/adc/ad7887.h b/drivers/staging/iio/adc/ad7887.h
new file mode 100644
index 0000000..8c2a218
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7887.h
@@ -0,0 +1,105 @@
+/*
+ * AD7887 SPI ADC driver
+ *
+ * Copyright 2010 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+#ifndef IIO_ADC_AD7887_H_
+#define IIO_ADC_AD7887_H_
+
+#define AD7887_REF_DIS (1 << 5) /* on-chip reference disable */
+#define AD7887_DUAL (1 << 4) /* dual-channel mode */
+#define AD7887_CH_AIN1 (1 << 3) /* convert on channel 1, DUAL=1 */
+#define AD7887_CH_AIN0 (0 << 3) /* convert on channel 0, DUAL=0,1 */
+#define AD7887_PM_MODE1 (0) /* CS based shutdown */
+#define AD7887_PM_MODE2 (1) /* full on */
+#define AD7887_PM_MODE3 (2) /* auto shutdown after conversion */
+#define AD7887_PM_MODE4 (3) /* standby mode */
+
+enum ad7887_channels {
+ AD7887_CH0,
+ AD7887_CH0_CH1,
+ AD7887_CH1,
+};
+
+#define RES_MASK(bits) ((1 << (bits)) - 1) /* TODO: move this into a common header */
+
+/*
+ * TODO: struct ad7887_platform_data needs to go into include/linux/iio
+ */
+
+struct ad7887_platform_data {
+ /* External Vref voltage applied */
+ u16 vref_mv;
+ /*
+ * AD7887:
+ * In single channel mode en_dual = flase, AIN1/Vref pins assumes its
+ * Vref function. In dual channel mode en_dual = true, AIN1 becomes the
+ * second input channel, and Vref is internally connected to Vdd.
+ */
+ bool en_dual;
+ /*
+ * AD7887:
+ * use_onchip_ref = true, the Vref is internally connected to the 2.500V
+ * Voltage reference. If use_onchip_ref = false, the reference voltage
+ * is supplied by AIN1/Vref
+ */
+ bool use_onchip_ref;
+};
+
+struct ad7887_chip_info {
+ u8 bits; /* number of ADC bits */
+ u8 storagebits; /* number of bits read from the ADC */
+ u8 left_shift; /* number of bits the sample must be shifted */
+ char sign; /* [s]igned or [u]nsigned */
+ u16 int_vref_mv; /* internal reference voltage */
+};
+
+struct ad7887_state {
+ struct iio_dev *indio_dev;
+ struct spi_device *spi;
+ const struct ad7887_chip_info *chip_info;
+ struct regulator *reg;
+ struct work_struct poll_work;
+ atomic_t protect_ring;
+ u16 int_vref_mv;
+ bool en_dual;
+ struct spi_transfer xfer[4];
+ struct spi_message msg[3];
+ struct spi_message *ring_msg;
+ unsigned char tx_cmd_buf[8];
+
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ */
+
+ unsigned char data[4] ____cacheline_aligned;
+};
+
+enum ad7887_supported_device_ids {
+ ID_AD7887
+};
+
+#ifdef CONFIG_IIO_RING_BUFFER
+int ad7887_scan_from_ring(struct ad7887_state *st, long mask);
+int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev);
+void ad7887_ring_cleanup(struct iio_dev *indio_dev);
+#else /* CONFIG_IIO_RING_BUFFER */
+static inline int ad7887_scan_from_ring(struct ad7887_state *st, long mask)
+{
+ return 0;
+}
+
+static inline int
+ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev)
+{
+ return 0;
+}
+
+static inline void ad7887_ring_cleanup(struct iio_dev *indio_dev)
+{
+}
+#endif /* CONFIG_IIO_RING_BUFFER */
+#endif /* IIO_ADC_AD7887_H_ */
diff --git a/drivers/staging/iio/adc/ad7887_core.c b/drivers/staging/iio/adc/ad7887_core.c
new file mode 100644
index 0000000..6859089
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7887_core.c
@@ -0,0 +1,305 @@
+/*
+ * AD7887 SPI ADC driver
+ *
+ * Copyright 2010 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+#include <linux/spi/spi.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../ring_generic.h"
+#include "adc.h"
+
+#include "ad7887.h"
+
+static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
+{
+ int ret = spi_sync(st->spi, &st->msg[ch]);
+ if (ret)
+ return ret;
+
+ return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
+}
+
+static ssize_t ad7887_scan(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7887_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 = ad7887_scan_from_ring(st, 1 << this_attr->address);
+ else
+ ret = ad7887_scan_direct(st, this_attr->address);
+ mutex_unlock(&dev_info->mlock);
+
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", (ret >> st->chip_info->left_shift) &
+ RES_MASK(st->chip_info->bits));
+}
+static IIO_DEV_ATTR_IN_RAW(0, ad7887_scan, 0);
+static IIO_DEV_ATTR_IN_RAW(1, ad7887_scan, 1);
+
+static ssize_t ad7887_show_scale(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ /* Driver currently only support internal vref */
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7887_state *st = iio_dev_get_devdata(dev_info);
+ /* Corresponds to Vref / 2^(bits) */
+ unsigned int scale_uv = (st->int_vref_mv * 1000) >> st->chip_info->bits;
+
+ return sprintf(buf, "%d.%d\n", scale_uv / 1000, scale_uv % 1000);
+}
+static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7887_show_scale, NULL, 0);
+
+static ssize_t ad7887_show_name(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7887_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, ad7887_show_name, NULL, 0);
+
+static struct attribute *ad7887_attributes[] = {
+ &iio_dev_attr_in0_raw.dev_attr.attr,
+ &iio_dev_attr_in1_raw.dev_attr.attr,
+ &iio_dev_attr_in_scale.dev_attr.attr,
+ &iio_dev_attr_name.dev_attr.attr,
+ NULL,
+};
+
+static mode_t ad7887_attr_is_visible(struct kobject *kobj,
+ struct attribute *attr, int n)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7887_state *st = iio_dev_get_devdata(dev_info);
+
+ mode_t mode = attr->mode;
+
+ if ((attr == &iio_dev_attr_in1_raw.dev_attr.attr) && !st->en_dual)
+ mode = 0;
+
+ return mode;
+}
+
+static const struct attribute_group ad7887_attribute_group = {
+ .attrs = ad7887_attributes,
+ .is_visible = ad7887_attr_is_visible,
+};
+
+static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
+ /*
+ * More devices added in future
+ */
+ [ID_AD7887] = {
+ .bits = 12,
+ .storagebits = 16,
+ .left_shift = 0,
+ .sign = IIO_SCAN_EL_TYPE_UNSIGNED,
+ .int_vref_mv = 2500,
+ },
+};
+
+static int __devinit ad7887_probe(struct spi_device *spi)
+{
+ struct ad7887_platform_data *pdata = spi->dev.platform_data;
+ struct ad7887_state *st;
+ int ret, voltage_uv = 0;
+
+ 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;
+
+ voltage_uv = regulator_get_voltage(st->reg);
+ }
+
+ st->chip_info =
+ &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+ 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;
+ }
+
+ /* Estabilish that the iio_dev is a child of the spi device */
+ st->indio_dev->dev.parent = &spi->dev;
+ st->indio_dev->attrs = &ad7887_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->tx_cmd_buf[0] = AD7887_CH_AIN0 | AD7887_PM_MODE4 |
+ ((pdata && pdata->use_onchip_ref) ?
+ 0 : AD7887_REF_DIS);
+
+ st->xfer[0].rx_buf = &st->data[0];
+ st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
+ st->xfer[0].len = 2;
+
+ spi_message_init(&st->msg[AD7887_CH0]);
+ spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
+
+ if (pdata && pdata->en_dual) {
+ st->tx_cmd_buf[0] |= AD7887_DUAL | AD7887_REF_DIS;
+
+ st->tx_cmd_buf[2] = AD7887_CH_AIN1 | AD7887_DUAL |
+ AD7887_REF_DIS | AD7887_PM_MODE4;
+ st->tx_cmd_buf[4] = AD7887_CH_AIN0 | AD7887_DUAL |
+ AD7887_REF_DIS | AD7887_PM_MODE4;
+ st->tx_cmd_buf[6] = AD7887_CH_AIN1 | AD7887_DUAL |
+ AD7887_REF_DIS | AD7887_PM_MODE4;
+
+ st->xfer[1].rx_buf = &st->data[0];
+ st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
+ st->xfer[1].len = 2;
+
+ st->xfer[2].rx_buf = &st->data[2];
+ st->xfer[2].tx_buf = &st->tx_cmd_buf[4];
+ st->xfer[2].len = 2;
+
+ spi_message_init(&st->msg[AD7887_CH0_CH1]);
+ spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
+ spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
+
+ st->xfer[3].rx_buf = &st->data[0];
+ st->xfer[3].tx_buf = &st->tx_cmd_buf[6];
+ st->xfer[3].len = 2;
+
+ spi_message_init(&st->msg[AD7887_CH1]);
+ spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
+
+ st->en_dual = true;
+
+ if (pdata && pdata->vref_mv)
+ st->int_vref_mv = pdata->vref_mv;
+ else if (voltage_uv)
+ st->int_vref_mv = voltage_uv / 1000;
+ else
+ dev_warn(&spi->dev, "reference voltage unspecified\n");
+
+ } else {
+ if (pdata && pdata->vref_mv)
+ st->int_vref_mv = pdata->vref_mv;
+ else if (pdata && pdata->use_onchip_ref)
+ st->int_vref_mv = st->chip_info->int_vref_mv;
+ else
+ dev_warn(&spi->dev, "reference voltage unspecified\n");
+ }
+
+
+ ret = ad7887_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:
+ ad7887_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 ad7887_remove(struct spi_device *spi)
+{
+ struct ad7887_state *st = spi_get_drvdata(spi);
+ struct iio_dev *indio_dev = st->indio_dev;
+ iio_ring_buffer_unregister(indio_dev->ring);
+ ad7887_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 ad7887_id[] = {
+ {"ad7887", ID_AD7887},
+ {}
+};
+
+static struct spi_driver ad7887_driver = {
+ .driver = {
+ .name = "ad7887",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = ad7887_probe,
+ .remove = __devexit_p(ad7887_remove),
+ .id_table = ad7887_id,
+};
+
+static int __init ad7887_init(void)
+{
+ return spi_register_driver(&ad7887_driver);
+}
+module_init(ad7887_init);
+
+static void __exit ad7887_exit(void)
+{
+ spi_unregister_driver(&ad7887_driver);
+}
+module_exit(ad7887_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich at blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("spi:ad7887");
diff --git a/drivers/staging/iio/adc/ad7887_ring.c b/drivers/staging/iio/adc/ad7887_ring.c
new file mode 100644
index 0000000..6b9cb1f
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7887_ring.c
@@ -0,0 +1,266 @@
+/*
+ * Copyright 2010 Analog Devices Inc.
+ * Copyright (C) 2008 Jonathan Cameron
+ *
+ * Licensed under the GPL-2 or later.
+ *
+ * ad7887_ring.c
+ */
+
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+#include <linux/spi/spi.h>
+
+#include "../iio.h"
+#include "../ring_generic.h"
+#include "../ring_sw.h"
+#include "../trigger.h"
+#include "../sysfs.h"
+
+#include "ad7887.h"
+
+static IIO_SCAN_EL_C(in0, 0, 0, NULL);
+static IIO_SCAN_EL_C(in1, 1, 0, NULL);
+
+static ssize_t ad7887_show_type(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_ring_buffer *ring = dev_get_drvdata(dev);
+ struct iio_dev *indio_dev = ring->indio_dev;
+ struct ad7887_state *st = indio_dev->dev_data;
+
+ return sprintf(buf, "%c%d/%d>>%d\n", st->chip_info->sign,
+ st->chip_info->bits, st->chip_info->storagebits,
+ st->chip_info->left_shift);
+}
+static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7887_show_type, NULL, 0);
+
+static struct attribute *ad7887_scan_el_attrs[] = {
+ &iio_scan_el_in0.dev_attr.attr,
+ &iio_const_attr_in0_index.dev_attr.attr,
+ &iio_scan_el_in1.dev_attr.attr,
+ &iio_const_attr_in1_index.dev_attr.attr,
+ &iio_dev_attr_in_type.dev_attr.attr,
+ NULL,
+};
+
+static mode_t ad7887_scan_el_attr_is_visible(struct kobject *kobj,
+ struct attribute *attr, int n)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct iio_ring_buffer *ring = dev_get_drvdata(dev);
+ struct iio_dev *indio_dev = ring->indio_dev;
+ struct ad7887_state *st = indio_dev->dev_data;
+
+ mode_t mode = attr->mode;
+
+ if ((attr == &iio_scan_el_in1.dev_attr.attr) ||
+ (attr == &iio_const_attr_in1_index.dev_attr.attr))
+ if (!st->en_dual)
+ mode = 0;
+
+ return mode;
+}
+
+static struct attribute_group ad7887_scan_el_group = {
+ .name = "scan_elements",
+ .attrs = ad7887_scan_el_attrs,
+ .is_visible = ad7887_scan_el_attr_is_visible,
+};
+
+int ad7887_scan_from_ring(struct ad7887_state *st, long mask)
+{
+ struct iio_ring_buffer *ring = st->indio_dev->ring;
+ int count = 0, ret;
+ u16 *ring_data;
+
+ if (!(ring->scan_mask & mask)) {
+ ret = -EBUSY;
+ goto error_ret;
+ }
+
+ ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
+ if (ring_data == NULL) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ ret = ring->access.read_last(ring, (u8 *) ring_data);
+ if (ret)
+ goto error_free_ring_data;
+
+ /* for single channel scan the result is stored with zero offset */
+ if ((ring->scan_mask == ((1 << 1) | (1 << 0))) && (mask == (1 << 1)))
+ count = 1;
+
+ ret = be16_to_cpu(ring_data[count]);
+
+error_free_ring_data:
+ kfree(ring_data);
+error_ret:
+ return ret;
+}
+
+/**
+ * ad7887_ring_preenable() setup the parameters of the ring before enabling
+ *
+ * The complex nature of the setting of the nuber of bytes per datum is due
+ * to this driver currently ensuring that the timestamp is stored at an 8
+ * byte boundary.
+ **/
+static int ad7887_ring_preenable(struct iio_dev *indio_dev)
+{
+ struct ad7887_state *st = indio_dev->dev_data;
+ struct iio_ring_buffer *ring = indio_dev->ring;
+ size_t d_size;
+
+ if (indio_dev->ring->access.set_bytes_per_datum) {
+ d_size = st->chip_info->storagebits / 8 + sizeof(s64);
+ if (d_size % 8)
+ d_size += 8 - (d_size % 8);
+ indio_dev->ring->access.set_bytes_per_datum(indio_dev->ring,
+ d_size);
+ }
+
+ switch (ring->scan_mask) {
+ case (1 << 0):
+ st->ring_msg = &st->msg[AD7887_CH0];
+ break;
+ case (1 << 1):
+ st->ring_msg = &st->msg[AD7887_CH1];
+ /* Dummy read: push CH1 setting down to hardware */
+ spi_sync(st->spi, st->ring_msg);
+ break;
+ case ((1 << 1) | (1 << 0)):
+ st->ring_msg = &st->msg[AD7887_CH0_CH1];
+ break;
+ }
+
+ return 0;
+}
+
+static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
+{
+ struct ad7887_state *st = indio_dev->dev_data;
+
+ /* dummy read: restore default CH0 settin */
+ return spi_sync(st->spi, &st->msg[AD7887_CH0]);
+}
+
+/**
+ * ad7887_poll_func_th() th of trigger launched polling to ring buffer
+ *
+ * As sampling only occurs on spi comms occuring, leave timestamping until
+ * then. Some triggers will generate their own time stamp. Currently
+ * there is no way of notifying them when no one cares.
+ **/
+static void ad7887_poll_func_th(struct iio_dev *indio_dev, s64 time)
+{
+ struct ad7887_state *st = indio_dev->dev_data;
+
+ schedule_work(&st->poll_work);
+ return;
+}
+/**
+ * ad7887_poll_bh_to_ring() bh of trigger launched polling to ring buffer
+ * @work_s: the work struct through which this was scheduled
+ *
+ * Currently there is no option in this driver to disable the saving of
+ * timestamps within the ring.
+ * I think the one copy of this at a time was to avoid problems if the
+ * trigger was set far too high and the reads then locked up the computer.
+ **/
+static void ad7887_poll_bh_to_ring(struct work_struct *work_s)
+{
+ struct ad7887_state *st = container_of(work_s, struct ad7887_state,
+ poll_work);
+ struct iio_dev *indio_dev = st->indio_dev;
+ struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
+ struct iio_ring_buffer *ring = indio_dev->ring;
+ s64 time_ns;
+ __u8 *buf;
+ int b_sent;
+ size_t d_size;
+
+ unsigned int bytes = ring->scan_count * st->chip_info->storagebits / 8;
+
+ /* Ensure the timestamp is 8 byte aligned */
+ d_size = bytes + sizeof(s64);
+ if (d_size % sizeof(s64))
+ d_size += sizeof(s64) - (d_size % sizeof(s64));
+
+ /* Ensure only one copy of this function running at a time */
+ if (atomic_inc_return(&st->protect_ring) > 1)
+ return;
+
+ buf = kzalloc(d_size, GFP_KERNEL);
+ if (buf == NULL)
+ return;
+
+ b_sent = spi_sync(st->spi, st->ring_msg);
+ if (b_sent)
+ goto done;
+
+ time_ns = iio_get_time_ns();
+
+ memcpy(buf, st->data, bytes);
+ memcpy(buf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
+
+ indio_dev->ring->access.store_to(&sw_ring->buf, buf, time_ns);
+done:
+ kfree(buf);
+ atomic_dec(&st->protect_ring);
+}
+
+int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev)
+{
+ struct ad7887_state *st = indio_dev->dev_data;
+ int ret;
+
+ indio_dev->ring = iio_sw_rb_allocate(indio_dev);
+ if (!indio_dev->ring) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ /* Effectively select the ring buffer implementation */
+ iio_ring_sw_register_funcs(&indio_dev->ring->access);
+ ret = iio_alloc_pollfunc(indio_dev, NULL, &ad7887_poll_func_th);
+ if (ret)
+ goto error_deallocate_sw_rb;
+
+ /* Ring buffer functions - here trigger setup related */
+
+ indio_dev->ring->preenable = &ad7887_ring_preenable;
+ indio_dev->ring->postenable = &iio_triggered_ring_postenable;
+ indio_dev->ring->predisable = &iio_triggered_ring_predisable;
+ indio_dev->ring->postdisable = &ad7887_ring_postdisable;
+ indio_dev->ring->scan_el_attrs = &ad7887_scan_el_group;
+
+ INIT_WORK(&st->poll_work, &ad7887_poll_bh_to_ring);
+
+ /* Flag that polled ring buffering is possible */
+ indio_dev->modes |= INDIO_RING_TRIGGERED;
+ return 0;
+error_deallocate_sw_rb:
+ iio_sw_rb_free(indio_dev->ring);
+error_ret:
+ return ret;
+}
+
+void ad7887_ring_cleanup(struct iio_dev *indio_dev)
+{
+ /* ensure that the trigger has been detached */
+ if (indio_dev->trig) {
+ iio_put_trigger(indio_dev->trig);
+ iio_trigger_dettach_poll_func(indio_dev->trig,
+ indio_dev->pollfunc);
+ }
+ kfree(indio_dev->pollfunc);
+ iio_sw_rb_free(indio_dev->ring);
+}
--
1.7.3.2
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