--- /dev/null
+/*
+ * rfd77402.c - Support for RF Digital RFD77402 Time-of-Flight (distance) sensor
+ *
+ * Copyright 2017 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
+ *
+ * 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.
+ *
+ * 7-bit I2C slave address 0x4c
+ *
+ * TODO: interrupt
+ * https://media.digikey.com/pdf/Data%20Sheets/RF%20Digital%20PDFs/RFD77402.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+
+#define RFD77402_DRV_NAME "rfd77402"
+
+#define RFD77402_ICSR 0x00 /* Interrupt Control Status Register */
+#define RFD77402_ICSR_INT_MODE BIT(2)
+#define RFD77402_ICSR_INT_POL BIT(3)
+#define RFD77402_ICSR_RESULT BIT(4)
+#define RFD77402_ICSR_M2H_MSG BIT(5)
+#define RFD77402_ICSR_H2M_MSG BIT(6)
+#define RFD77402_ICSR_RESET BIT(7)
+
+#define RFD77402_CMD_R 0x04
+#define RFD77402_CMD_SINGLE 0x01
+#define RFD77402_CMD_STANDBY 0x10
+#define RFD77402_CMD_MCPU_OFF 0x11
+#define RFD77402_CMD_MCPU_ON 0x12
+#define RFD77402_CMD_RESET BIT(6)
+#define RFD77402_CMD_VALID BIT(7)
+
+#define RFD77402_STATUS_R 0x06
+#define RFD77402_STATUS_PM_MASK GENMASK(4, 0)
+#define RFD77402_STATUS_STANDBY 0x00
+#define RFD77402_STATUS_MCPU_OFF 0x10
+#define RFD77402_STATUS_MCPU_ON 0x18
+
+#define RFD77402_RESULT_R 0x08
+#define RFD77402_RESULT_DIST_MASK GENMASK(12, 2)
+#define RFD77402_RESULT_ERR_MASK GENMASK(14, 13)
+#define RFD77402_RESULT_VALID BIT(15)
+
+#define RFD77402_PMU_CFG 0x14
+#define RFD77402_PMU_MCPU_INIT BIT(9)
+
+#define RFD77402_I2C_INIT_CFG 0x1c
+#define RFD77402_I2C_ADDR_INCR BIT(0)
+#define RFD77402_I2C_DATA_INCR BIT(2)
+#define RFD77402_I2C_HOST_DEBUG BIT(5)
+#define RFD77402_I2C_MCPU_DEBUG BIT(6)
+
+#define RFD77402_CMD_CFGR_A 0x0c
+#define RFD77402_CMD_CFGR_B 0x0e
+#define RFD77402_HFCFG_0 0x20
+#define RFD77402_HFCFG_1 0x22
+#define RFD77402_HFCFG_2 0x24
+#define RFD77402_HFCFG_3 0x26
+
+#define RFD77402_MOD_CHIP_ID 0x28
+
+/* magic configuration values from datasheet */
+static const struct {
+ u8 reg;
+ u16 val;
+} rf77402_tof_config[] = {
+ {RFD77402_CMD_CFGR_A, 0xe100},
+ {RFD77402_CMD_CFGR_B, 0x10ff},
+ {RFD77402_HFCFG_0, 0x07d0},
+ {RFD77402_HFCFG_1, 0x5008},
+ {RFD77402_HFCFG_2, 0xa041},
+ {RFD77402_HFCFG_3, 0x45d4},
+};
+
+struct rfd77402_data {
+ struct i2c_client *client;
+ /* Serialize reads from the sensor */
+ struct mutex lock;
+};
+
+static const struct iio_chan_spec rfd77402_channels[] = {
+ {
+ .type = IIO_DISTANCE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static int rfd77402_set_state(struct rfd77402_data *data, u8 state, u16 check)
+{
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(data->client, RFD77402_CMD_R,
+ state | RFD77402_CMD_VALID);
+ if (ret < 0)
+ return ret;
+
+ usleep_range(10000, 20000);
+
+ ret = i2c_smbus_read_word_data(data->client, RFD77402_STATUS_R);
+ if (ret < 0)
+ return ret;
+ if ((ret & RFD77402_STATUS_PM_MASK) != check)
+ return -ENODEV;
+
+ return 0;
+}
+
+static int rfd77402_measure(struct rfd77402_data *data)
+{
+ int ret;
+ int tries = 10;
+
+ ret = rfd77402_set_state(data, RFD77402_CMD_MCPU_ON,
+ RFD77402_STATUS_MCPU_ON);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_write_byte_data(data->client, RFD77402_CMD_R,
+ RFD77402_CMD_SINGLE |
+ RFD77402_CMD_VALID);
+ if (ret < 0)
+ goto err;
+
+ while (tries-- > 0) {
+ ret = i2c_smbus_read_byte_data(data->client, RFD77402_ICSR);
+ if (ret < 0)
+ goto err;
+ if (ret & RFD77402_ICSR_RESULT)
+ break;
+ msleep(20);
+ }
+
+ if (tries < 0) {
+ ret = -ETIMEDOUT;
+ goto err;
+ }
+
+ ret = i2c_smbus_read_word_data(data->client, RFD77402_RESULT_R);
+ if (ret < 0)
+ goto err;
+
+ if ((ret & RFD77402_RESULT_ERR_MASK) ||
+ !(ret & RFD77402_RESULT_VALID)) {
+ ret = -EIO;
+ goto err;
+ }
+
+ return (ret & RFD77402_RESULT_DIST_MASK) >> 2;
+
+err:
+ rfd77402_set_state(data, RFD77402_CMD_MCPU_OFF,
+ RFD77402_STATUS_MCPU_OFF);
+ return ret;
+}
+
+static int rfd77402_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct rfd77402_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&data->lock);
+ ret = rfd77402_measure(data);
+ mutex_unlock(&data->lock);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ /* 1 LSB is 1 mm */
+ *val = 0;
+ *val2 = 1000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info rfd77402_info = {
+ .read_raw = rfd77402_read_raw,
+};
+
+static int rfd77402_init(struct rfd77402_data *data)
+{
+ int ret, i;
+
+ ret = rfd77402_set_state(data, RFD77402_CMD_STANDBY,
+ RFD77402_STATUS_STANDBY);
+ if (ret < 0)
+ return ret;
+
+ /* configure INT pad as push-pull, active low */
+ ret = i2c_smbus_write_byte_data(data->client, RFD77402_ICSR,
+ RFD77402_ICSR_INT_MODE);
+ if (ret < 0)
+ return ret;
+
+ /* I2C configuration */
+ ret = i2c_smbus_write_word_data(data->client, RFD77402_I2C_INIT_CFG,
+ RFD77402_I2C_ADDR_INCR |
+ RFD77402_I2C_DATA_INCR |
+ RFD77402_I2C_HOST_DEBUG |
+ RFD77402_I2C_MCPU_DEBUG);
+ if (ret < 0)
+ return ret;
+
+ /* set initialization */
+ ret = i2c_smbus_write_word_data(data->client, RFD77402_PMU_CFG, 0x0500);
+ if (ret < 0)
+ return ret;
+
+ ret = rfd77402_set_state(data, RFD77402_CMD_MCPU_OFF,
+ RFD77402_STATUS_MCPU_OFF);
+ if (ret < 0)
+ return ret;
+
+ /* set initialization */
+ ret = i2c_smbus_write_word_data(data->client, RFD77402_PMU_CFG, 0x0600);
+ if (ret < 0)
+ return ret;
+
+ ret = rfd77402_set_state(data, RFD77402_CMD_MCPU_ON,
+ RFD77402_STATUS_MCPU_ON);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < ARRAY_SIZE(rf77402_tof_config); i++) {
+ ret = i2c_smbus_write_word_data(data->client,
+ rf77402_tof_config[i].reg,
+ rf77402_tof_config[i].val);
+ if (ret < 0)
+ return ret;
+ }
+
+ ret = rfd77402_set_state(data, RFD77402_CMD_STANDBY,
+ RFD77402_STATUS_STANDBY);
+
+ return ret;
+}
+
+static int rfd77402_powerdown(struct rfd77402_data *data)
+{
+ return rfd77402_set_state(data, RFD77402_CMD_STANDBY,
+ RFD77402_STATUS_STANDBY);
+}
+
+static int rfd77402_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct rfd77402_data *data;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ ret = i2c_smbus_read_word_data(client, RFD77402_MOD_CHIP_ID);
+ if (ret < 0)
+ return ret;
+ if (ret != 0xad01 && ret != 0xad02) /* known chip ids */
+ 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;
+ mutex_init(&data->lock);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &rfd77402_info;
+ indio_dev->channels = rfd77402_channels;
+ indio_dev->num_channels = ARRAY_SIZE(rfd77402_channels);
+ indio_dev->name = RFD77402_DRV_NAME;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ ret = rfd77402_init(data);
+ if (ret < 0)
+ return ret;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto err_powerdown;
+
+ return 0;
+
+err_powerdown:
+ rfd77402_powerdown(data);
+ return ret;
+}
+
+static int rfd77402_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+ iio_device_unregister(indio_dev);
+ rfd77402_powerdown(iio_priv(indio_dev));
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int rfd77402_suspend(struct device *dev)
+{
+ struct rfd77402_data *data = iio_priv(i2c_get_clientdata(
+ to_i2c_client(dev)));
+
+ return rfd77402_powerdown(data);
+}
+
+static int rfd77402_resume(struct device *dev)
+{
+ struct rfd77402_data *data = iio_priv(i2c_get_clientdata(
+ to_i2c_client(dev)));
+
+ return rfd77402_init(data);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(rfd77402_pm_ops, rfd77402_suspend, rfd77402_resume);
+
+static const struct i2c_device_id rfd77402_id[] = {
+ { "rfd77402", 0},
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, rfd77402_id);
+
+static struct i2c_driver rfd77402_driver = {
+ .driver = {
+ .name = RFD77402_DRV_NAME,
+ .pm = &rfd77402_pm_ops,
+ },
+ .probe = rfd77402_probe,
+ .remove = rfd77402_remove,
+ .id_table = rfd77402_id,
+};
+
+module_i2c_driver(rfd77402_driver);
+
+MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("RFD77402 Time-of-Flight sensor driver");
+MODULE_LICENSE("GPL");
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