From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
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@xxxxxxxxxx>
Acked-by: Jonathan Cameron <jic23@xxxxxxxxx>
---
drivers/staging/iio/adc/Kconfig | 11 ++
drivers/staging/iio/adc/Makefile | 1 +
drivers/staging/iio/adc/ad7780.c | 329 ++++++++++++++++++++++++++++++++++++++
drivers/staging/iio/adc/ad7780.h | 30 ++++
4 files changed, 371 insertions(+), 0 deletions(-)
create mode 100644 drivers/staging/iio/adc/ad7780.c
create mode 100644 drivers/staging/iio/adc/ad7780.h
diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
index 6692a3d..4159389 100644
--- a/drivers/staging/iio/adc/Kconfig
+++ b/drivers/staging/iio/adc/Kconfig
@@ -142,6 +142,17 @@ config AD7887
To compile this driver as a module, choose M here: the
module will be called ad7887.
+config AD7780
+ tristate "Analog Devices AD7780 AD7781 ADC driver"
+ depends on SPI
+ help
+ Say yes here to build support for Analog Devices
+ AD7780 and AD7781 SPI analog to digital convertors (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 ad7780.
+
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 31067de..1d9b3f5 100644
--- a/drivers/staging/iio/adc/Makefile
+++ b/drivers/staging/iio/adc/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_AD7152) += ad7152.o
obj-$(CONFIG_AD7291) += ad7291.o
obj-$(CONFIG_AD7314) += ad7314.o
obj-$(CONFIG_AD7745) += ad7745.o
+obj-$(CONFIG_AD7780) += ad7780.o
obj-$(CONFIG_AD7816) += ad7816.o
obj-$(CONFIG_ADT75) += adt75.o
obj-$(CONFIG_ADT7310) += adt7310.o
diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
new file mode 100644
index 0000000..0fd994f
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7780.c
@@ -0,0 +1,329 @@
+/*
+ * AD7780/AD7781 SPI ADC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#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 <linux/sched.h>
+#include <linux/gpio.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../ring_generic.h"
+#include "adc.h"
+
+#include "ad7780.h"
+
+#define AD7780_RDY (1 << 7)
+#define AD7780_FILTER (1 << 6)
+#define AD7780_ERR (1 << 5)
+#define AD7780_ID1 (1 << 4)
+#define AD7780_ID0 (1 << 3)
+#define AD7780_GAIN (1 << 2)
+#define AD7780_PAT1 (1 << 1)
+#define AD7780_PAT0 (1 << 0)
+
+struct ad7780_chip_info {
+ u8 bits;
+ u8 storagebits;
+ u8 res_shift;
+};
+
+struct ad7780_state {
+ struct iio_dev *indio_dev;
+ struct spi_device *spi;
+ const struct ad7780_chip_info *chip_info;
+ struct regulator *reg;
+ struct ad7780_platform_data *pdata;
+ wait_queue_head_t wq_data_avail;
+ bool done;
+ u16 int_vref_mv;
+ struct spi_transfer xfer;
+ struct spi_message msg;
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ */
+ unsigned int data ____cacheline_aligned;
+};
+
+enum ad7780_supported_device_ids {
+ ID_AD7780,
+ ID_AD7781,
+};
+
+static int ad7780_read(struct ad7780_state *st, int *val)
+{
+ int ret;
+
+ spi_bus_lock(st->spi->master);
+
+ enable_irq(st->spi->irq);
+ st->done = false;
+ gpio_set_value(st->pdata->gpio_pdrst, 1);
+
+ ret = wait_event_interruptible(st->wq_data_avail, st->done);
+ disable_irq_nosync(st->spi->irq);
+ if (ret)
+ goto out;
+
+ ret = spi_sync_locked(st->spi, &st->msg);
+ *val = be32_to_cpu(st->data);
+out:
+ gpio_set_value(st->pdata->gpio_pdrst, 0);
+ spi_bus_unlock(st->spi->master);
+
+ return ret;
+}
+
+static ssize_t ad7780_scan(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7780_state *st = dev_info->dev_data;
+ int ret, val, smpl;
+
+ mutex_lock(&dev_info->mlock);
+ ret = ad7780_read(st, &smpl);
+ mutex_unlock(&dev_info->mlock);
+
+ if (ret < 0)
+ return ret;
+
+ if ((smpl & AD7780_ERR) ||
+ !((smpl & AD7780_PAT0) && !(smpl & AD7780_PAT1)))
+ return -EIO;
+
+ val = (smpl >> st->chip_info->res_shift) &
+ ((1 << (st->chip_info->bits)) - 1);
+ val -= (1 << (st->chip_info->bits - 1));
+
+ if (!(smpl & AD7780_GAIN))
+ val *= 128;
+
+ return sprintf(buf, "%d\n", val);
+}
+static IIO_DEV_ATTR_IN_RAW(0, ad7780_scan, 0);
+
+static ssize_t ad7780_show_scale(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7780_state *st = iio_dev_get_devdata(dev_info);
+ /* Corresponds to Vref / 2^(bits-1) */
+ unsigned int scale = (st->int_vref_mv * 100000) >>
+ (st->chip_info->bits - 1);
+
+ return sprintf(buf, "%d.%05d\n", scale / 100000, scale % 100000);
+}
+static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7780_show_scale, NULL, 0);
+
+static ssize_t ad7780_show_name(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct ad7780_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, ad7780_show_name, NULL, 0);
+
+static struct attribute *ad7780_attributes[] = {
+ &iio_dev_attr_in0_raw.dev_attr.attr,
+ &iio_dev_attr_in_scale.dev_attr.attr,
+ &iio_dev_attr_name.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group ad7780_attribute_group = {
+ .attrs = ad7780_attributes,
+};
+
+static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
+ [ID_AD7780] = {
+ .bits = 24,
+ .storagebits = 32,
+ .res_shift = 8,
+ },
+ [ID_AD7781] = {
+ .bits = 20,
+ .storagebits = 32,
+ .res_shift = 12,
+ },
+};
+
+/**
+ * Interrupt handler
+ */
+static irqreturn_t ad7780_interrupt(int irq, void *dev_id)
+{
+ struct ad7780_state *st = dev_id;
+
+ st->done = true;
+ wake_up_interruptible(&st->wq_data_avail);
+
+ return IRQ_HANDLED;
+};
+
+static int __devinit ad7780_probe(struct spi_device *spi)
+{
+ struct ad7780_platform_data *pdata = spi->dev.platform_data;
+ struct ad7780_state *st;
+ int ret, voltage_uv = 0;
+
+ if (!pdata) {
+ dev_dbg(&spi->dev, "no platform data?\n");
+ return -ENODEV;
+ }
+
+ 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 =
+ &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+ st->pdata = pdata;
+
+ 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");
+
+ spi_set_drvdata(spi, st);
+ st->spi = spi;
+
+ st->indio_dev = iio_allocate_device();
+ if (st->indio_dev == NULL) {
+ ret = -ENOMEM;
+ goto error_disable_reg;
+ }
+
+ /* Establish that the iio_dev is a child of the spi device */
+ st->indio_dev->dev.parent = &spi->dev;
+ st->indio_dev->attrs = &ad7780_attribute_group;
+ st->indio_dev->dev_data = (void *)(st);
+ st->indio_dev->driver_module = THIS_MODULE;
+ st->indio_dev->modes = INDIO_DIRECT_MODE;
+
+ init_waitqueue_head(&st->wq_data_avail);
+
+ /* Setup default message */
+
+ st->xfer.rx_buf = &st->data;
+ st->xfer.len = st->chip_info->storagebits / 8;
+
+ spi_message_init(&st->msg);
+ spi_message_add_tail(&st->xfer, &st->msg);
+
+ ret = gpio_request_one(st->pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
+ "AD7877 /PDRST");
+ if (ret) {
+ dev_err(&spi->dev, "failed to request GPIO PDRST\n");
+ goto error_free_device;
+ }
+
+ ret = request_irq(spi->irq, ad7780_interrupt,
+ IRQF_TRIGGER_FALLING, spi_get_device_id(spi)->name, st);
+ if (ret)
+ goto error_free_device;
+
+ disable_irq(spi->irq);
+
+ ret = iio_device_register(st->indio_dev);
+ if (ret)
+ goto error_free_irq;
+
+ return 0;
+
+error_free_irq:
+ free_irq(spi->irq, st);
+
+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 ad7780_remove(struct spi_device *spi)
+{
+ struct ad7780_state *st = spi_get_drvdata(spi);
+ struct iio_dev *indio_dev = st->indio_dev;
+ free_irq(spi->irq, st);
+ gpio_free(st->pdata->gpio_pdrst);
+ 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 ad7780_id[] = {
+ {"ad7780", ID_AD7780},
+ {"ad7781", ID_AD7781},
+ {}
+};
+
+static struct spi_driver ad7780_driver = {
+ .driver = {
+ .name = "ad7780",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = ad7780_probe,
+ .remove = __devexit_p(ad7780_remove),
+ .id_table = ad7780_id,
+};
+
+static int __init ad7780_init(void)
+{
+ return spi_register_driver(&ad7780_driver);
+}
+module_init(ad7780_init);
+
+static void __exit ad7780_exit(void)
+{
+ spi_unregister_driver(&ad7780_driver);
+}
+module_exit(ad7780_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@xxxxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Devices AD7780/1 ADC");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/iio/adc/ad7780.h b/drivers/staging/iio/adc/ad7780.h
new file mode 100644
index 0000000..67e511c
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7780.h
@@ -0,0 +1,30 @@
+/*
+ * AD7780/AD7781 SPI ADC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+#ifndef IIO_ADC_AD7780_H_
+#define IIO_ADC_AD7780_H_
+
+/*
+ * TODO: struct ad7780_platform_data needs to go into include/linux/iio
+ */
+
+/* NOTE:
+ * The AD7780 doesn't feature a dedicated SPI chip select, in addition it
+ * features a dual use data out ready DOUT/RDY output.
+ * In order to avoid contentions on the SPI bus, it's therefore necessary
+ * to use spi bus locking combined with a dedicated GPIO to control the
+ * power down reset signal of the AD7780.
+ *
+ * The DOUT/RDY output must also be wired to an interrupt capable GPIO.
+ */
+
+struct ad7780_platform_data {
+ u16 vref_mv;
+ int gpio_pdrst;
+};
+
+#endif /* IIO_ADC_AD7780_H_ */
--
1.6.0.2
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