1 files changed, 559 insertions, 0 deletions

diff --git a/drivers/iio/proximity/srf08.c b/drivers/iio/proximity/srf08.c
new file mode 100644
index 000000000..9b0886760
--- /dev/null
+++ b/drivers/iio/proximity/srf08.c
@@ -0,0 +1,559 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * srf08.c - Support for Devantech SRFxx ultrasonic ranger
+ *           with i2c interface
+ * actually supported are srf02, srf08, srf10
+ *
+ * Copyright (c) 2016, 2017 Andreas Klinger <ak@it-klinger.de>
+ *
+ * For details about the device see:
+ * https://www.robot-electronics.co.uk/htm/srf08tech.html
+ * https://www.robot-electronics.co.uk/htm/srf10tech.htm
+ * https://www.robot-electronics.co.uk/htm/srf02tech.htm
+ */
+
+#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>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.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 */
+
+enum srf08_sensor_type {
+	SRF02,
+	SRF08,
+	SRF10,
+	SRF_MAX_TYPE
+};
+
+struct srf08_chip_info {
+	const int		*sensitivity_avail;
+	int			num_sensitivity_avail;
+	int			sensitivity_default;
+
+	/* default value of Range in mm */
+	int			range_default;
+};
+
+struct srf08_data {
+	struct i2c_client	*client;
+
+	/*
+	 * Gain in the datasheet is called sensitivity here to distinct it
+	 * from the gain used with amplifiers of adc's
+	 */
+	int			sensitivity;
+
+	/* max. Range in mm */
+	int			range_mm;
+	struct mutex		lock;
+
+	/* Ensure timestamp is naturally aligned */
+	struct {
+		s16 chan;
+		s64 timestamp __aligned(8);
+	} scan;
+
+	/* Sensor-Type */
+	enum srf08_sensor_type	sensor_type;
+
+	/* Chip-specific information */
+	const struct srf08_chip_info	*chip_info;
+};
+
+/*
+ * 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 struct srf08_chip_info srf02_chip_info = {
+	.sensitivity_avail	= NULL,
+	.num_sensitivity_avail	= 0,
+	.sensitivity_default	= 0,
+
+	.range_default		= 0,
+};
+
+static const int srf08_sensitivity_avail[] = {
+	 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 const struct srf08_chip_info srf08_chip_info = {
+	.sensitivity_avail	= srf08_sensitivity_avail,
+	.num_sensitivity_avail	= ARRAY_SIZE(srf08_sensitivity_avail),
+	.sensitivity_default	= 1025,
+
+	.range_default		= 6020,
+};
+
+static const int srf10_sensitivity_avail[] = {
+	 40,  40,  50,  60,  70,  80, 100, 120,
+	140, 200, 250, 300, 350, 400, 500, 600,
+	700,
+	};
+
+static const struct srf08_chip_info srf10_chip_info = {
+	.sensitivity_avail	= srf10_sensitivity_avail,
+	.num_sensitivity_avail	= ARRAY_SIZE(srf10_sensitivity_avail),
+	.sensitivity_default	= 700,
+
+	.range_default		= 6020,
+};
+
+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 irqreturn_t srf08_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct srf08_data *data = iio_priv(indio_dev);
+	s16 sensor_data;
+
+	sensor_data = srf08_read_ranging(data);
+	if (sensor_data < 0)
+		goto err;
+
+	mutex_lock(&data->lock);
+
+	data->scan.chan = sensor_data;
+	iio_push_to_buffers_with_timestamp(indio_dev,
+					   &data->scan, pf->timestamp);
+
+	mutex_unlock(&data->lock);
+err:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
+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;
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct srf08_data *data = iio_priv(indio_dev);
+
+	for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
+		if (data->chip_info->sensitivity_avail[i])
+			len += sprintf(buf + len, "%d ",
+				data->chip_info->sensitivity_avail[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;
+
+	if (!val)
+		return -EINVAL;
+
+	for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
+		if (val && (val == data->chip_info->sensitivity_avail[i])) {
+			regval = i;
+			break;
+		}
+
+	if (i >= data->chip_info->num_sensitivity_avail)
+		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),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_CPU,
+		},
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static const struct iio_info srf08_info = {
+	.read_raw = srf08_read_raw,
+	.attrs = &srf08_attribute_group,
+};
+
+/*
+ * srf02 don't have an adjustable range or sensitivity,
+ * so we don't need attributes at all
+ */
+static const struct iio_info srf02_info = {
+	.read_raw = srf08_read_raw,
+};
+
+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;
+	data->sensor_type = (enum srf08_sensor_type)id->driver_data;
+
+	switch (data->sensor_type) {
+	case SRF02:
+		data->chip_info = &srf02_chip_info;
+		indio_dev->info = &srf02_info;
+		break;
+	case SRF08:
+		data->chip_info = &srf08_chip_info;
+		indio_dev->info = &srf08_info;
+		break;
+	case SRF10:
+		data->chip_info = &srf10_chip_info;
+		indio_dev->info = &srf08_info;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	indio_dev->name = id->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = srf08_channels;
+	indio_dev->num_channels = ARRAY_SIZE(srf08_channels);
+
+	mutex_init(&data->lock);
+
+	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
+			iio_pollfunc_store_time, srf08_trigger_handler, NULL);
+	if (ret < 0) {
+		dev_err(&client->dev, "setup of iio triggered buffer failed\n");
+		return ret;
+	}
+
+	if (data->chip_info->range_default) {
+		/*
+		 * set default range of device in mm here
+		 * these register values cannot be read from the hardware
+		 * therefore set driver specific default values
+		 *
+		 * srf02 don't have a default value so it'll be omitted
+		 */
+		ret = srf08_write_range_mm(data,
+					data->chip_info->range_default);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (data->chip_info->sensitivity_default) {
+		/*
+		 * set default sensitivity of device here
+		 * these register values cannot be read from the hardware
+		 * therefore set driver specific default values
+		 *
+		 * srf02 don't have a default value so it'll be omitted
+		 */
+		ret = srf08_write_sensitivity(data,
+				data->chip_info->sensitivity_default);
+		if (ret < 0)
+			return ret;
+	}
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct of_device_id of_srf08_match[] = {
+	{ .compatible = "devantech,srf02", (void *)SRF02},
+	{ .compatible = "devantech,srf08", (void *)SRF08},
+	{ .compatible = "devantech,srf10", (void *)SRF10},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, of_srf08_match);
+
+static const struct i2c_device_id srf08_id[] = {
+	{ "srf02", SRF02 },
+	{ "srf08", SRF08 },
+	{ "srf10", SRF10 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, srf08_id);
+
+static struct i2c_driver srf08_driver = {
+	.driver = {
+		.name	= "srf08",
+		.of_match_table	= of_srf08_match,
+	},
+	.probe = srf08_probe,
+	.id_table = srf08_id,
+};
+module_i2c_driver(srf08_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
+MODULE_DESCRIPTION("Devantech SRF02/SRF08/SRF10 i2c ultrasonic ranger driver");
+MODULE_LICENSE("GPL");