From: Michael Hennerich Date: Mon, 22 Nov 2010 13:35:32 +0000 (+0100) Subject: staging: iio: adc: Enable driver support for ad7887 AD converter X-Git-Tag: v3.0~2451^2~245 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2b4756aa36909a94596752db341a0a2c8bb8c6ea;p=platform%2Fkernel%2Flinux-amlogic.git staging: iio: adc: Enable driver support for ad7887 AD converter 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 Acked-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 "); +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 +#include +#include +#include +#include +#include +#include +#include +#include + +#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); +}