--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * mb1232.c - Support for MaxBotix I2CXL-MaxSonar-EZ series ultrasonic
+ * ranger with i2c interface
+ * actually tested with mb1232 type
+ *
+ * Copyright (c) 2019 Andreas Klinger <ak@it-klinger.de>
+ *
+ * For details about the device see:
+ * https://www.maxbotix.com/documents/I2CXL-MaxSonar-EZ_Datasheet.pdf
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/of_irq.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 MaxSonar device */
+#define MB1232_RANGE_COMMAND 0x51 /* Command for reading range */
+#define MB1232_ADDR_UNLOCK_1 0xAA /* Command 1 for changing address */
+#define MB1232_ADDR_UNLOCK_2 0xA5 /* Command 2 for changing address */
+
+struct mb1232_data {
+ struct i2c_client *client;
+
+ struct mutex lock;
+
+ /*
+ * optionally a gpio can be used to announce when ranging has
+ * finished
+ * since we are just using the falling trigger of it we request
+ * only the interrupt for announcing when data is ready to be read
+ */
+ struct completion ranging;
+ int irqnr;
+};
+
+static irqreturn_t mb1232_handle_irq(int irq, void *dev_id)
+{
+ struct iio_dev *indio_dev = dev_id;
+ struct mb1232_data *data = iio_priv(indio_dev);
+
+ complete(&data->ranging);
+
+ return IRQ_HANDLED;
+}
+
+static s16 mb1232_read_distance(struct mb1232_data *data)
+{
+ struct i2c_client *client = data->client;
+ int ret;
+ s16 distance;
+ __be16 buf;
+
+ mutex_lock(&data->lock);
+
+ reinit_completion(&data->ranging);
+
+ ret = i2c_smbus_write_byte(client, MB1232_RANGE_COMMAND);
+ if (ret < 0) {
+ dev_err(&client->dev, "write command - err: %d\n", ret);
+ goto error_unlock;
+ }
+
+ if (data->irqnr >= 0) {
+ /* it cannot take more than 100 ms */
+ ret = wait_for_completion_killable_timeout(&data->ranging,
+ HZ/10);
+ if (ret < 0)
+ goto error_unlock;
+ else if (ret == 0) {
+ ret = -ETIMEDOUT;
+ goto error_unlock;
+ }
+ } else {
+ /* use simple sleep if announce irq is not connected */
+ msleep(15);
+ }
+
+ ret = i2c_master_recv(client, (char *)&buf, sizeof(buf));
+ if (ret < 0) {
+ dev_err(&client->dev, "i2c_master_recv: ret=%d\n", ret);
+ goto error_unlock;
+ }
+
+ distance = __be16_to_cpu(buf);
+ /* check for not returning misleading error codes */
+ if (distance < 0) {
+ dev_err(&client->dev, "distance=%d\n", distance);
+ ret = -EINVAL;
+ goto error_unlock;
+ }
+
+ mutex_unlock(&data->lock);
+
+ return distance;
+
+error_unlock:
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static irqreturn_t mb1232_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct mb1232_data *data = iio_priv(indio_dev);
+ /*
+ * triggered buffer
+ * 16-bit channel + 48-bit padding + 64-bit timestamp
+ */
+ s16 buffer[8] = { 0 };
+
+ buffer[0] = mb1232_read_distance(data);
+ if (buffer[0] < 0)
+ goto err;
+
+ iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp);
+
+err:
+ iio_trigger_notify_done(indio_dev->trig);
+ return IRQ_HANDLED;
+}
+
+static int mb1232_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel, int *val,
+ int *val2, long mask)
+{
+ struct mb1232_data *data = iio_priv(indio_dev);
+ int ret;
+
+ if (channel->type != IIO_DISTANCE)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = mb1232_read_distance(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 const struct iio_chan_spec mb1232_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 mb1232_info = {
+ .read_raw = mb1232_read_raw,
+};
+
+static int mb1232_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct mb1232_data *data;
+ int ret;
+ struct device *dev = &client->dev;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_BYTE |
+ I2C_FUNC_SMBUS_WRITE_BYTE))
+ return -ENODEV;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+
+ indio_dev->info = &mb1232_info;
+ indio_dev->name = id->name;
+ indio_dev->dev.parent = dev;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = mb1232_channels;
+ indio_dev->num_channels = ARRAY_SIZE(mb1232_channels);
+
+ mutex_init(&data->lock);
+
+ init_completion(&data->ranging);
+
+ data->irqnr = irq_of_parse_and_map(dev->of_node, 0);
+ if (data->irqnr <= 0) {
+ /* usage of interrupt is optional */
+ data->irqnr = -1;
+ } else {
+ ret = devm_request_irq(dev, data->irqnr, mb1232_handle_irq,
+ IRQF_TRIGGER_FALLING, id->name, indio_dev);
+ if (ret < 0) {
+ dev_err(dev, "request_irq: %d\n", ret);
+ return ret;
+ }
+ }
+
+ ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+ iio_pollfunc_store_time, mb1232_trigger_handler, NULL);
+ if (ret < 0) {
+ dev_err(dev, "setup of iio triggered buffer failed\n");
+ return ret;
+ }
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id of_mb1232_match[] = {
+ { .compatible = "maxbotix,mb1202", },
+ { .compatible = "maxbotix,mb1212", },
+ { .compatible = "maxbotix,mb1222", },
+ { .compatible = "maxbotix,mb1232", },
+ { .compatible = "maxbotix,mb1242", },
+ { .compatible = "maxbotix,mb7040", },
+ { .compatible = "maxbotix,mb7137", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, of_mb1232_match);
+
+static const struct i2c_device_id mb1232_id[] = {
+ { "maxbotix-mb1202", },
+ { "maxbotix-mb1212", },
+ { "maxbotix-mb1222", },
+ { "maxbotix-mb1232", },
+ { "maxbotix-mb1242", },
+ { "maxbotix-mb7040", },
+ { "maxbotix-mb7137", },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mb1232_id);
+
+static struct i2c_driver mb1232_driver = {
+ .driver = {
+ .name = "maxbotix-mb1232",
+ .of_match_table = of_mb1232_match,
+ },
+ .probe = mb1232_probe,
+ .id_table = mb1232_id,
+};
+module_i2c_driver(mb1232_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
+MODULE_DESCRIPTION("Maxbotix I2CXL-MaxSonar i2c ultrasonic ranger driver");
+MODULE_LICENSE("GPL");
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