1 files changed, 398 insertions, 0 deletions
diff --git a/drivers/iio/proximity/srf08.c b/drivers/iio/proximity/srf08.c
new file mode 100644
index 000000000000..49316cbf7c60
--- /dev/null
+++ b/drivers/iio/proximity/srf08.c
@@ -0,0 +1,398 @@
+/*
+ * srf08.c - Support for Devantech SRF08 ultrasonic ranger
+ *
+ * Copyright (c) 2016 Andreas Klinger <ak@it-klinger.de>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * For details about the device see:
+ * http://www.robot-electronics.co.uk/htm/srf08tech.html
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/* registers of SRF08 device */
+#define SRF08_WRITE_COMMAND	0x00	/* Command Register */
+#define SRF08_WRITE_MAX_GAIN	0x01	/* Max Gain Register: 0 .. 31 */
+#define SRF08_WRITE_RANGE	0x02	/* Range Register: 0 .. 255 */
+#define SRF08_READ_SW_REVISION	0x00	/* Software Revision */
+#define SRF08_READ_LIGHT	0x01	/* Light Sensor during last echo */
+#define SRF08_READ_ECHO_1_HIGH	0x02	/* Range of first echo received */
+#define SRF08_READ_ECHO_1_LOW	0x03	/* Range of first echo received */
+
+#define SRF08_CMD_RANGING_CM	0x51	/* Ranging Mode - Result in cm */
+
+#define SRF08_DEFAULT_GAIN	1025	/* default analogue value of Gain */
+#define SRF08_DEFAULT_RANGE	6020	/* default value of Range in mm */
+
+struct srf08_data {
+	struct i2c_client	*client;
+	int			sensitivity;		/* Gain */
+	int			range_mm;		/* max. Range in mm */
+	struct mutex		lock;
+};
+
+/*
+ * in the documentation one can read about the "Gain" of the device
+ * which is used here for amplifying the signal and filtering out unwanted
+ * ones.
+ * But with ADC's this term is already used differently and that's why it
+ * is called "Sensitivity" here.
+ */
+static const int srf08_sensitivity[] = {
+	 94,  97, 100, 103, 107, 110, 114, 118,
+	123, 128, 133, 139, 145, 152, 159, 168,
+	177, 187, 199, 212, 227, 245, 265, 288,
+	317, 352, 395, 450, 524, 626, 777, 1025 };
+
+static int srf08_read_ranging(struct srf08_data *data)
+{
+	struct i2c_client *client = data->client;
+	int ret, i;
+	int waittime;
+
+	mutex_lock(&data->lock);
+
+	ret = i2c_smbus_write_byte_data(data->client,
+			SRF08_WRITE_COMMAND, SRF08_CMD_RANGING_CM);
+	if (ret < 0) {
+		dev_err(&client->dev, "write command - err: %d\n", ret);
+		mutex_unlock(&data->lock);
+		return ret;
+	}
+
+	/*
+	 * we read here until a correct version number shows up as
+	 * suggested by the documentation
+	 *
+	 * with an ultrasonic speed of 343 m/s and a roundtrip of it
+	 * sleep the expected duration and try to read from the device
+	 * if nothing useful is read try it in a shorter grid
+	 *
+	 * polling for not more than 20 ms should be enough
+	 */
+	waittime = 1 + data->range_mm / 172;
+	msleep(waittime);
+	for (i = 0; i < 4; i++) {
+		ret = i2c_smbus_read_byte_data(data->client,
+						SRF08_READ_SW_REVISION);
+
+		/* check if a valid version number is read */
+		if (ret < 255 && ret > 0)
+			break;
+		msleep(5);
+	}
+
+	if (ret >= 255 || ret <= 0) {
+		dev_err(&client->dev, "device not ready\n");
+		mutex_unlock(&data->lock);
+		return -EIO;
+	}
+
+	ret = i2c_smbus_read_word_swapped(data->client,
+						SRF08_READ_ECHO_1_HIGH);
+	if (ret < 0) {
+		dev_err(&client->dev, "cannot read distance: ret=%d\n", ret);
+		mutex_unlock(&data->lock);
+		return ret;
+	}
+
+	mutex_unlock(&data->lock);
+
+	return ret;
+}
+
+static int srf08_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *channel, int *val,
+			    int *val2, long mask)
+{
+	struct srf08_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (channel->type != IIO_DISTANCE)
+		return -EINVAL;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = srf08_read_ranging(data);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* 1 LSB is 1 cm */
+		*val = 0;
+		*val2 = 10000;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static ssize_t srf08_show_range_mm_available(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "[0.043 0.043 11.008]\n");
+}
+
+static IIO_DEVICE_ATTR(sensor_max_range_available, S_IRUGO,
+				srf08_show_range_mm_available, NULL, 0);
+
+static ssize_t srf08_show_range_mm(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct srf08_data *data = iio_priv(indio_dev);
+
+	return sprintf(buf, "%d.%03d\n", data->range_mm / 1000,
+						data->range_mm % 1000);
+}
+
+/*
+ * set the range of the sensor to an even multiple of 43 mm
+ * which corresponds to 1 LSB in the register
+ *
+ * register value    corresponding range
+ *         0x00             43 mm
+ *         0x01             86 mm
+ *         0x02            129 mm
+ *         ...
+ *         0xFF          11008 mm
+ */
+static ssize_t srf08_write_range_mm(struct srf08_data *data, unsigned int val)
+{
+	int ret;
+	struct i2c_client *client = data->client;
+	unsigned int mod;
+	u8 regval;
+
+	ret = val / 43 - 1;
+	mod = val % 43;
+
+	if (mod || (ret < 0) || (ret > 255))
+		return -EINVAL;
+
+	regval = ret;
+
+	mutex_lock(&data->lock);
+
+	ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_RANGE, regval);
+	if (ret < 0) {
+		dev_err(&client->dev, "write_range - err: %d\n", ret);
+		mutex_unlock(&data->lock);
+		return ret;
+	}
+
+	data->range_mm = val;
+
+	mutex_unlock(&data->lock);
+
+	return 0;
+}
+
+static ssize_t srf08_store_range_mm(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct srf08_data *data = iio_priv(indio_dev);
+	int ret;
+	int integer, fract;
+
+	ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);
+	if (ret)
+		return ret;
+
+	ret = srf08_write_range_mm(data, integer * 1000 + fract);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(sensor_max_range, S_IRUGO | S_IWUSR,
+			srf08_show_range_mm, srf08_store_range_mm, 0);
+
+static ssize_t srf08_show_sensitivity_available(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	int i, len = 0;
+
+	for (i = 0; i < ARRAY_SIZE(srf08_sensitivity); i++)
+		len += sprintf(buf + len, "%d ", srf08_sensitivity[i]);
+
+	len += sprintf(buf + len, "\n");
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(sensor_sensitivity_available, S_IRUGO,
+				srf08_show_sensitivity_available, NULL, 0);
+
+static ssize_t srf08_show_sensitivity(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct srf08_data *data = iio_priv(indio_dev);
+	int len;
+
+	len = sprintf(buf, "%d\n", data->sensitivity);
+
+	return len;
+}
+
+static ssize_t srf08_write_sensitivity(struct srf08_data *data,
+							unsigned int val)
+{
+	struct i2c_client *client = data->client;
+	int ret, i;
+	u8 regval;
+
+	for (i = 0; i < ARRAY_SIZE(srf08_sensitivity); i++)
+		if (val == srf08_sensitivity[i]) {
+			regval = i;
+			break;
+		}
+
+	if (i >= ARRAY_SIZE(srf08_sensitivity))
+		return -EINVAL;
+
+	mutex_lock(&data->lock);
+
+	ret = i2c_smbus_write_byte_data(client,
+						SRF08_WRITE_MAX_GAIN, regval);
+	if (ret < 0) {
+		dev_err(&client->dev, "write_sensitivity - err: %d\n", ret);
+		mutex_unlock(&data->lock);
+		return ret;
+	}
+
+	data->sensitivity = val;
+
+	mutex_unlock(&data->lock);
+
+	return 0;
+}
+
+static ssize_t srf08_store_sensitivity(struct device *dev,
+						struct device_attribute *attr,
+						const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct srf08_data *data = iio_priv(indio_dev);
+	int ret;
+	unsigned int val;
+
+	ret = kstrtouint(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	ret = srf08_write_sensitivity(data, val);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
+			srf08_show_sensitivity, srf08_store_sensitivity, 0);
+
+static struct attribute *srf08_attributes[] = {
+	&iio_dev_attr_sensor_max_range.dev_attr.attr,
+	&iio_dev_attr_sensor_max_range_available.dev_attr.attr,
+	&iio_dev_attr_sensor_sensitivity.dev_attr.attr,
+	&iio_dev_attr_sensor_sensitivity_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group srf08_attribute_group = {
+	.attrs = srf08_attributes,
+};
+
+static const struct iio_chan_spec srf08_channels[] = {
+	{
+		.type = IIO_DISTANCE,
+		.info_mask_separate =
+				BIT(IIO_CHAN_INFO_RAW) |
+				BIT(IIO_CHAN_INFO_SCALE),
+	},
+};
+
+static const struct iio_info srf08_info = {
+	.read_raw = srf08_read_raw,
+	.attrs = &srf08_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static int srf08_probe(struct i2c_client *client,
+					 const struct i2c_device_id *id)
+{
+	struct iio_dev *indio_dev;
+	struct srf08_data *data;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+					I2C_FUNC_SMBUS_READ_BYTE_DATA |
+					I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+					I2C_FUNC_SMBUS_READ_WORD_DATA))
+		return -ENODEV;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	indio_dev->name = "srf08";
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &srf08_info;
+	indio_dev->channels = srf08_channels;
+	indio_dev->num_channels = ARRAY_SIZE(srf08_channels);
+
+	mutex_init(&data->lock);
+
+	/*
+	 * set default values of device here
+	 * these register values cannot be read from the hardware
+	 * therefore set driver specific default values
+	 */
+	ret = srf08_write_range_mm(data, SRF08_DEFAULT_RANGE);
+	if (ret < 0)
+		return ret;
+
+	ret = srf08_write_sensitivity(data, SRF08_DEFAULT_GAIN);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id srf08_id[] = {
+	{ "srf08", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, srf08_id);
+
+static struct i2c_driver srf08_driver = {
+	.driver = {
+		.name	= "srf08",
+	},
+	.probe = srf08_probe,
+	.id_table = srf08_id,
+};
+module_i2c_driver(srf08_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
+MODULE_DESCRIPTION("Devantech SRF08 ultrasonic ranger driver");
+MODULE_LICENSE("GPL");