iio: proximity: Add rfd77402 driver

Driver for RF Digital RFD77402 VCSEL (vertical-cavity surface-emitting
laser) Time-of-Flight (ToF) sensor to measure distance up to 2 m with
millimeter precision

Signed-off-by: Peter Meerwald-Stadler <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/proximity/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called pulsedlight-lite-v2
 
+config RFD77402
+	tristate "RFD77402 ToF sensor"
+	depends on I2C
+	help
+	  Say Y to build a driver for the RFD77420 Time-of-Flight (distance)
+	  sensor module with I2C interface.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rfd77402.
+
 config SRF04
 	tristate "Devantech SRF04 ultrasonic ranger sensor"
 	depends on GPIOLIB

drivers/iio/proximity/Makefile

···
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AS3935)		+= as3935.o
 obj-$(CONFIG_LIDAR_LITE_V2)	+= pulsedlight-lidar-lite-v2.o
+obj-$(CONFIG_RFD77402)		+= rfd77402.o
 obj-$(CONFIG_SRF04)		+= srf04.o
 obj-$(CONFIG_SRF08)		+= srf08.o
 obj-$(CONFIG_SX9500)		+= sx9500.o

drivers/iio/proximity/rfd77402.c

···
+/*
+ * rfd77402.c - Support for RF Digital RFD77402 Time-of-Flight (distance) sensor
+ *
+ * Copyright 2017 Peter Meerwald-Stadler <[e-mail]>
+ *
+ * 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 <[e-mail]>");
+MODULE_DESCRIPTION("RFD77402 Time-of-Flight sensor driver");
+MODULE_LICENSE("GPL");