[PATCH V3.3] adds support for Texas Instruments ads1110 adc

[Pirmin Duss <pirmin.duss@flytec.ch>]

From: Duss Pirmin <pirmin.duss@flytec.ch>

Version 3.3
	fixes things found by Jonathan Cameron
Version 3.2
        fixes coding errors found by Lars-Peter Clausen
        uses the new module_i2c_driver() macro
Version 3.1
        patch against staging-next
Version 3
        removed boiler plate comments
        removed table for gain/scale
        removed trivial wrapper function
        added locking around access to configuration
        scale is done via infomask

Signed-off-by: Duss Pirmin <pirmin.duss@flytec.ch>
---
 drivers/staging/iio/adc/Kconfig   |   10 ++
 drivers/staging/iio/adc/Makefile  |    1 +
 drivers/staging/iio/adc/ads1110.c |  323 +++++++++++++++++++++++++++++++++++++
 3 files changed, 334 insertions(+), 0 deletions(-)
 create mode 100644 drivers/staging/iio/adc/ads1110.c

diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
index d9decea..ab516dd 100644
--- a/drivers/staging/iio/adc/Kconfig
+++ b/drivers/staging/iio/adc/Kconfig
@@ -145,6 +145,16 @@ config AD7192
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad7192.
 
+config ADS1110
+	tristate "Texas Instruments ADS1110 Analog Digital Converter driver"
+	depends on I2C
+	help
+		Say yes here to build support for Texas Instruments ads1110 ADC.
+		Provides direct access via sysfs.
+
+		To compile this driver as a module, choose M here: the
+		module will be called ads1110.
+
 config ADT7310
 	tristate "Analog Devices ADT7310 temperature sensor driver"
 	depends on SPI
diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
index ceee7f3..5551e03 100644
--- a/drivers/staging/iio/adc/Makefile
+++ b/drivers/staging/iio/adc/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_AD7780) += ad7780.o
 obj-$(CONFIG_AD7793) += ad7793.o
 obj-$(CONFIG_AD7816) += ad7816.o
 obj-$(CONFIG_AD7192) += ad7192.o
+obj-$(CONFIG_ADS1110) += ads1110.o
 obj-$(CONFIG_ADT7310) += adt7310.o
 obj-$(CONFIG_ADT7410) += adt7410.o
 obj-$(CONFIG_AD7280) += ad7280a.o
diff --git a/drivers/staging/iio/adc/ads1110.c b/drivers/staging/iio/adc/ads1110.c
new file mode 100644
index 0000000..6445de8
--- /dev/null
+++ b/drivers/staging/iio/adc/ads1110.c
@@ -0,0 +1,323 @@
+/*
+ * Driver for Texas Instruments ads1110 ADC.
+ *
+ * Datashhet con be found on: http://www.ti.com/lit/ds/symlink/ads1110.pdf
+ *
+ * Copyright 2011 Flytec AG.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/err.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+
+#define ADS1110_DATA_BYTES		2
+#define ADS1110_CONFIG_BYTES		3
+
+#define ADS1110_CYC_MASK		0x0C
+#define ADS1110_CYC_SHIFT		2
+#define ADS1110_CYC_15			3
+#define ADS1110_CYC_30			2
+#define ADS1110_CYC_60			1
+#define ADS1110_CYC_240			0
+
+#define ADS1110_PGA_MASK		0x03
+#define ADS1110_PGA_COUNT		4
+
+struct ads1110_chip_info {
+	struct i2c_client	*client;
+	u8	config;
+};
+
+static const unsigned int ads1110_frequencies[] = {
+	[ADS1110_CYC_240] = 240,
+	[ADS1110_CYC_60] = 60,
+	[ADS1110_CYC_30] = 30,
+	[ADS1110_CYC_15] = 15,
+};
+
+static const struct iio_chan_spec ads1110_channels[] = {
+	IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 0, 0,
+		 IIO_CHAN_INFO_SCALE_SEPARATE_BIT, 0, 0,
+		 IIO_ST('s', 16, 16, 0), 0),
+};
+
+static int ads1110_i2c_read_config(struct ads1110_chip_info *chip, u8 *data)
+{
+	int ret = 0;
+	u8 tmp[ADS1110_CONFIG_BYTES];
+
+	ret = i2c_master_recv(chip->client, tmp, ADS1110_CONFIG_BYTES);
+	if (ret != ADS1110_CONFIG_BYTES) {
+		dev_err(&chip->client->dev, "I2C read error\n");
+		return -EIO;
+	}
+
+	*data = tmp[2];
+
+	return 0;
+}
+
+static int ads1110_i2c_read_data(struct ads1110_chip_info *chip, int *data)
+{
+	int ret = 0;
+	__be16 tmp;
+
+	ret = i2c_master_recv(chip->client, (char *)&tmp, ADS1110_DATA_BYTES);
+	if (ret != ADS1110_DATA_BYTES) {
+		dev_err(&chip->client->dev, "I2C read error\n");
+		return -EIO;
+	}
+
+	*data = be16_to_cpu(tmp);
+
+	return 0;
+}
+
+static ssize_t ads1110_read_frequency(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ads1110_chip_info *st = iio_priv(indio_dev);
+	u8 cfg;
+
+	mutex_lock(&indio_dev->mlock);
+	cfg = ((st->config & ADS1110_CYC_MASK) >> ADS1110_CYC_SHIFT);
+	mutex_unlock(&indio_dev->mlock);
+
+	return sprintf(buf, "%d\n", ads1110_frequencies[cfg]);
+}
+
+static ssize_t ads1110_write_frequency(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf,
+				       size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ads1110_chip_info *st = iio_priv(indio_dev);
+	unsigned long lval;
+	int ret, i;
+
+	mutex_lock(&indio_dev->mlock);
+	ret = kstrtoul(buf, 10, &lval);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < ARRAY_SIZE(ads1110_frequencies); i++)
+		if (lval == ads1110_frequencies[i])
+			break;
+
+	if (i == ARRAY_SIZE(ads1110_frequencies)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	st->config &= ~ADS1110_CYC_MASK;
+	st->config |= (i << ADS1110_CYC_SHIFT);
+
+	ret = i2c_master_send(st->client, &st->config, 1);
+	if (ret < 0) {
+		ret = -EIO;
+		dev_err(&st->client->dev, "I2C write error\n");
+	}
+
+out:
+	mutex_unlock(&indio_dev->mlock);
+	return ret < 0 ? ret : len;
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
+		ads1110_read_frequency,
+		ads1110_write_frequency);
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("240 60 30 15");
+
+static IIO_CONST_ATTR(in_voltage_scale_available, "1 2 4 8");
+
+static int ads1110_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val,
+			    int *val2,
+			    long mask)
+{
+	struct ads1110_chip_info *st = iio_priv(indio_dev);
+	int ret, data, gain;
+
+	switch (mask) {
+	case 0:
+		mutex_lock(&indio_dev->mlock);
+		ret = ads1110_i2c_read_data(st, &data);
+		mutex_unlock(&indio_dev->mlock);
+
+		if (ret < 0)
+			return -EIO;
+
+		*val = data;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+
+		mutex_lock(&indio_dev->mlock);
+		gain = 1 << (st->config & ADS1110_PGA_MASK);
+		mutex_unlock(&indio_dev->mlock);
+
+		*val = gain;
+
+		return IIO_VAL_INT;
+	}
+	return -EINVAL;
+}
+
+static int ads1110_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val,
+			     int val2,
+			     long mask)
+{
+	struct ads1110_chip_info *st = iio_priv(indio_dev);
+	int ret, i;
+
+	mutex_lock(&indio_dev->mlock);
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		ret = -EINVAL;
+
+		for (i = 0; i < ADS1110_PGA_COUNT; i++) {
+			if (val == (1 << i))
+				break;
+		}
+
+		if (i == ADS1110_PGA_COUNT) {
+			ret = -EINVAL;
+			goto out;
+		}
+		if (st->config && i) {
+			ret = 0;
+			goto out;
+		}
+
+		st->config &= ~ADS1110_PGA_MASK;
+		st->config |= i;
+
+		ret = i2c_master_send(st->client, &st->config, 1);
+		if (ret < 0) {
+			ret = -EIO;
+			dev_err(&st->client->dev, "I2C write error\n");
+			goto out;
+		}
+		break;
+	default:
+		ret = -EINVAL;
+	}
+out:
+	mutex_unlock(&indio_dev->mlock);
+	return ret;
+}
+
+
+static struct attribute *ads1110_attributes[] = {
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_const_attr_in_voltage_scale_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ads1110_attribute_group = {
+	.attrs = ads1110_attributes,
+};
+
+static const struct iio_info ads1110_info = {
+	.attrs = &ads1110_attribute_group,
+	.read_raw = &ads1110_read_raw,
+	.write_raw = &ads1110_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int __devinit ads1110_probe(struct i2c_client *client,
+				   const struct i2c_device_id *id)
+{
+	int ret;
+	struct ads1110_chip_info *chip;
+	struct iio_dev *indio_dev;
+
+	indio_dev = iio_allocate_device(sizeof(*chip));
+	if (indio_dev == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+	chip = iio_priv(indio_dev);
+
+	/* this is only used for device removal purposes  */
+	i2c_set_clientdata(client, indio_dev);
+
+	chip->client = client;
+
+	/* Establish that the iio_dev is a child of the i2c device */
+	indio_dev->name = id->name;
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &ads1110_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ads1110_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ads1110_channels);
+
+	/* read the config register from the chip */
+	ret = ads1110_i2c_read_config(chip, &chip->config);
+	if (ret < 0)
+		goto error_free_dev;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_free_dev;
+
+	dev_err(&client->dev, "%s ADC registered.\n", id->name);
+
+	return 0;
+
+error_free_dev:
+	iio_free_device(indio_dev);
+	kfree(chip);
+error_ret:
+	return ret;
+}
+
+static int __devexit ads1110_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+	iio_free_device(indio_dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id ads1110_id[] = {
+	{ "ads1110", 0x00 },
+	{},
+};
+
+MODULE_DEVICE_TABLE(i2c, ads1110_id);
+
+static struct i2c_driver ads1110_driver = {
+	.driver = {
+		.name = "ads1110",
+	},
+	.probe = ads1110_probe,
+	.remove = __devexit_p(ads1110_remove),
+	.id_table = ads1110_id,
+};
+
+module_i2c_driver(ads1110_driver);
+
+MODULE_AUTHOR("Duss Pirmin <pirmin.duss@flytec.ch>");
+MODULE_DESCRIPTION("Texas Instruments ads1110 adc driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.2.5