staging: IIO: ADC: New driver for the AD7780 / AD7781 24-bit Sigma-Delta ADC
Changes since v1: IIO: ADC: AD7780: Apply review feedback Abort probe() with error in case platform_data is not present. Add comment explaining power down reset (PDRST) GPIO handling and dual function DOUT/RDY interrupt usage. Signed-off-by: Michael Hennerich <michael.hennerich@analog.com> Acked-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Michael Hennerich
Greg Kroah-Hartman
parent
8a789f8c30
commit
d6f087ec9c
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@ -142,6 +142,17 @@ config AD7887
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To compile this driver as a module, choose M here: the
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module will be called ad7887.
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config AD7780
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tristate "Analog Devices AD7780 AD7781 ADC driver"
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depends on SPI
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help
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Say yes here to build support for Analog Devices
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AD7780 and AD7781 SPI analog to digital convertors (ADC).
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If unsure, say N (but it's safe to say "Y").
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To compile this driver as a module, choose M here: the
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module will be called ad7780.
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config AD7745
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tristate "Analog Devices AD7745, AD7746 AD7747 capacitive sensor driver"
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depends on I2C
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@ -34,6 +34,7 @@ obj-$(CONFIG_AD7152) += ad7152.o
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obj-$(CONFIG_AD7291) += ad7291.o
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obj-$(CONFIG_AD7314) += ad7314.o
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obj-$(CONFIG_AD7745) += ad7745.o
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obj-$(CONFIG_AD7780) += ad7780.o
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obj-$(CONFIG_AD7816) += ad7816.o
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obj-$(CONFIG_ADT75) += adt75.o
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obj-$(CONFIG_ADT7310) += adt7310.o
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@ -0,0 +1,329 @@
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/*
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* AD7780/AD7781 SPI ADC driver
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*
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* Copyright 2011 Analog Devices Inc.
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*
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* Licensed under the GPL-2.
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*/
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#include <linux/interrupt.h>
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#include <linux/workqueue.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/list.h>
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#include <linux/spi/spi.h>
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#include <linux/regulator/consumer.h>
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <linux/gpio.h>
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#include "../iio.h"
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#include "../sysfs.h"
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#include "../ring_generic.h"
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#include "adc.h"
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#include "ad7780.h"
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#define AD7780_RDY (1 << 7)
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#define AD7780_FILTER (1 << 6)
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#define AD7780_ERR (1 << 5)
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#define AD7780_ID1 (1 << 4)
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#define AD7780_ID0 (1 << 3)
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#define AD7780_GAIN (1 << 2)
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#define AD7780_PAT1 (1 << 1)
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#define AD7780_PAT0 (1 << 0)
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struct ad7780_chip_info {
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u8 bits;
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u8 storagebits;
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u8 res_shift;
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};
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struct ad7780_state {
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struct iio_dev *indio_dev;
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struct spi_device *spi;
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const struct ad7780_chip_info *chip_info;
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struct regulator *reg;
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struct ad7780_platform_data *pdata;
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wait_queue_head_t wq_data_avail;
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bool done;
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u16 int_vref_mv;
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struct spi_transfer xfer;
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struct spi_message msg;
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/*
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* DMA (thus cache coherency maintenance) requires the
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* transfer buffers to live in their own cache lines.
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*/
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unsigned int data ____cacheline_aligned;
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};
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enum ad7780_supported_device_ids {
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ID_AD7780,
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ID_AD7781,
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};
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static int ad7780_read(struct ad7780_state *st, int *val)
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{
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int ret;
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spi_bus_lock(st->spi->master);
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enable_irq(st->spi->irq);
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st->done = false;
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gpio_set_value(st->pdata->gpio_pdrst, 1);
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ret = wait_event_interruptible(st->wq_data_avail, st->done);
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disable_irq_nosync(st->spi->irq);
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if (ret)
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goto out;
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ret = spi_sync_locked(st->spi, &st->msg);
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*val = be32_to_cpu(st->data);
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out:
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gpio_set_value(st->pdata->gpio_pdrst, 0);
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spi_bus_unlock(st->spi->master);
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return ret;
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}
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static ssize_t ad7780_scan(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7780_state *st = dev_info->dev_data;
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int ret, val, smpl;
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mutex_lock(&dev_info->mlock);
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ret = ad7780_read(st, &smpl);
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mutex_unlock(&dev_info->mlock);
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if (ret < 0)
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return ret;
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if ((smpl & AD7780_ERR) ||
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!((smpl & AD7780_PAT0) && !(smpl & AD7780_PAT1)))
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return -EIO;
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val = (smpl >> st->chip_info->res_shift) &
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((1 << (st->chip_info->bits)) - 1);
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val -= (1 << (st->chip_info->bits - 1));
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if (!(smpl & AD7780_GAIN))
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val *= 128;
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return sprintf(buf, "%d\n", val);
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}
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static IIO_DEV_ATTR_IN_RAW(0, ad7780_scan, 0);
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static ssize_t ad7780_show_scale(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7780_state *st = iio_dev_get_devdata(dev_info);
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/* Corresponds to Vref / 2^(bits-1) */
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unsigned int scale = (st->int_vref_mv * 100000) >>
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(st->chip_info->bits - 1);
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return sprintf(buf, "%d.%05d\n", scale / 100000, scale % 100000);
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}
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static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7780_show_scale, NULL, 0);
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static ssize_t ad7780_show_name(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7780_state *st = iio_dev_get_devdata(dev_info);
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return sprintf(buf, "%s\n", spi_get_device_id(st->spi)->name);
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}
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static IIO_DEVICE_ATTR(name, S_IRUGO, ad7780_show_name, NULL, 0);
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static struct attribute *ad7780_attributes[] = {
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&iio_dev_attr_in0_raw.dev_attr.attr,
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&iio_dev_attr_in_scale.dev_attr.attr,
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&iio_dev_attr_name.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ad7780_attribute_group = {
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.attrs = ad7780_attributes,
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};
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static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
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[ID_AD7780] = {
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.bits = 24,
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.storagebits = 32,
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.res_shift = 8,
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},
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[ID_AD7781] = {
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.bits = 20,
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.storagebits = 32,
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.res_shift = 12,
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},
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};
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/**
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* Interrupt handler
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*/
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static irqreturn_t ad7780_interrupt(int irq, void *dev_id)
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{
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struct ad7780_state *st = dev_id;
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st->done = true;
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wake_up_interruptible(&st->wq_data_avail);
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return IRQ_HANDLED;
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};
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static int __devinit ad7780_probe(struct spi_device *spi)
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{
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struct ad7780_platform_data *pdata = spi->dev.platform_data;
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struct ad7780_state *st;
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int ret, voltage_uv = 0;
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if (!pdata) {
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dev_dbg(&spi->dev, "no platform data?\n");
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return -ENODEV;
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}
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st = kzalloc(sizeof(*st), GFP_KERNEL);
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if (st == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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st->reg = regulator_get(&spi->dev, "vcc");
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if (!IS_ERR(st->reg)) {
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ret = regulator_enable(st->reg);
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if (ret)
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goto error_put_reg;
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voltage_uv = regulator_get_voltage(st->reg);
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}
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st->chip_info =
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&ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
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st->pdata = pdata;
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if (pdata && pdata->vref_mv)
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st->int_vref_mv = pdata->vref_mv;
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else if (voltage_uv)
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st->int_vref_mv = voltage_uv / 1000;
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else
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dev_warn(&spi->dev, "reference voltage unspecified\n");
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spi_set_drvdata(spi, st);
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st->spi = spi;
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st->indio_dev = iio_allocate_device();
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if (st->indio_dev == NULL) {
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ret = -ENOMEM;
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goto error_disable_reg;
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}
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/* Establish that the iio_dev is a child of the spi device */
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st->indio_dev->dev.parent = &spi->dev;
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st->indio_dev->attrs = &ad7780_attribute_group;
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st->indio_dev->dev_data = (void *)(st);
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st->indio_dev->driver_module = THIS_MODULE;
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st->indio_dev->modes = INDIO_DIRECT_MODE;
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init_waitqueue_head(&st->wq_data_avail);
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/* Setup default message */
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st->xfer.rx_buf = &st->data;
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st->xfer.len = st->chip_info->storagebits / 8;
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spi_message_init(&st->msg);
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spi_message_add_tail(&st->xfer, &st->msg);
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ret = gpio_request_one(st->pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
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"AD7877 /PDRST");
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if (ret) {
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dev_err(&spi->dev, "failed to request GPIO PDRST\n");
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goto error_free_device;
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}
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ret = request_irq(spi->irq, ad7780_interrupt,
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IRQF_TRIGGER_FALLING, spi_get_device_id(spi)->name, st);
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if (ret)
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goto error_free_device;
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disable_irq(spi->irq);
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ret = iio_device_register(st->indio_dev);
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if (ret)
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goto error_free_irq;
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return 0;
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error_free_irq:
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free_irq(spi->irq, st);
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error_free_device:
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iio_free_device(st->indio_dev);
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error_disable_reg:
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if (!IS_ERR(st->reg))
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regulator_disable(st->reg);
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error_put_reg:
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if (!IS_ERR(st->reg))
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regulator_put(st->reg);
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kfree(st);
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error_ret:
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return ret;
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}
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static int ad7780_remove(struct spi_device *spi)
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{
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struct ad7780_state *st = spi_get_drvdata(spi);
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struct iio_dev *indio_dev = st->indio_dev;
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free_irq(spi->irq, st);
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gpio_free(st->pdata->gpio_pdrst);
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iio_device_unregister(indio_dev);
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if (!IS_ERR(st->reg)) {
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regulator_disable(st->reg);
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regulator_put(st->reg);
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}
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kfree(st);
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return 0;
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}
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static const struct spi_device_id ad7780_id[] = {
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{"ad7780", ID_AD7780},
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{"ad7781", ID_AD7781},
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{}
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};
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static struct spi_driver ad7780_driver = {
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.driver = {
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.name = "ad7780",
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.bus = &spi_bus_type,
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.owner = THIS_MODULE,
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},
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.probe = ad7780_probe,
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.remove = __devexit_p(ad7780_remove),
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.id_table = ad7780_id,
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};
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static int __init ad7780_init(void)
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{
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return spi_register_driver(&ad7780_driver);
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}
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module_init(ad7780_init);
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static void __exit ad7780_exit(void)
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{
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spi_unregister_driver(&ad7780_driver);
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}
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module_exit(ad7780_exit);
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MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
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MODULE_DESCRIPTION("Analog Devices AD7780/1 ADC");
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MODULE_LICENSE("GPL v2");
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@ -0,0 +1,30 @@
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/*
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* AD7780/AD7781 SPI ADC driver
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*
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* Copyright 2011 Analog Devices Inc.
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*
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* Licensed under the GPL-2.
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*/
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#ifndef IIO_ADC_AD7780_H_
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#define IIO_ADC_AD7780_H_
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/*
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* TODO: struct ad7780_platform_data needs to go into include/linux/iio
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*/
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/* NOTE:
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* The AD7780 doesn't feature a dedicated SPI chip select, in addition it
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* features a dual use data out ready DOUT/RDY output.
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* In order to avoid contentions on the SPI bus, it's therefore necessary
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* to use spi bus locking combined with a dedicated GPIO to control the
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* power down reset signal of the AD7780.
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*
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* The DOUT/RDY output must also be wired to an interrupt capable GPIO.
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*/
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struct ad7780_platform_data {
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u16 vref_mv;
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int gpio_pdrst;
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};
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#endif /* IIO_ADC_AD7780_H_ */
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