iio: light: Add driver for IDT ZOPT2201 ambient light and UVB sensor

Driver for 20-bit ALS and UV B sensor with I2C interface exposing
the following API:
  in_uvindex_input
  in_illuminance_raw
  in_illuminance_scale
  in_illuminance_scale_available
  in_intensity_uv_raw
  in_intensity_uv_scale
  in_intensity_uv_scale_available
  integration_time
  integration_time_available

Signed-off-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

3 files changed, 579 insertions, 0 deletions

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 2356ed9285df..6a5835fab32e 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -425,4 +425,14 @@ config VL6180
 	 To compile this driver as a module, choose M here: the
 	 module will be called vl6180.
 
+config ZOPT2201
+	tristate "ZOPT2201 ALS and UV B sensor"
+	depends on I2C
+	help
+	 Say Y here if you want to build a driver for the IDT
+	 ZOPT2201 ambient light and UV B sensor.
+
+	 To compile this driver as a module, choose M here: the
+	 module will be called zopt2201.
+
 endmenu
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index c263469b7ce9..f0176a800e14 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -41,3 +41,4 @@ obj-$(CONFIG_US5182D)		+= us5182d.o
 obj-$(CONFIG_VCNL4000)		+= vcnl4000.o
 obj-$(CONFIG_VEML6070)		+= veml6070.o
 obj-$(CONFIG_VL6180)		+= vl6180.o
+obj-$(CONFIG_ZOPT2201)		+= zopt2201.o
diff --git a/drivers/iio/light/zopt2201.c b/drivers/iio/light/zopt2201.c
new file mode 100644
index 000000000000..041ac9effdb0
--- /dev/null
+++ b/drivers/iio/light/zopt2201.c
@@ -0,0 +1,568 @@
+/*
+ * zopt2201.c - Support for IDT ZOPT2201 ambient light and UV B 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.
+ *
+ * Datasheet: https://www.idt.com/document/dst/zopt2201-datasheet
+ * 7-bit I2C slave addresses 0x53 (default) or 0x52 (programmed)
+ *
+ * TODO: interrupt support, ALS/UVB raw mode
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define ZOPT2201_DRV_NAME "zopt2201"
+
+/* Registers */
+#define ZOPT2201_MAIN_CTRL		0x00
+#define ZOPT2201_LS_MEAS_RATE		0x04
+#define ZOPT2201_LS_GAIN		0x05
+#define ZOPT2201_PART_ID		0x06
+#define ZOPT2201_MAIN_STATUS		0x07
+#define ZOPT2201_ALS_DATA		0x0d /* LSB first, 13 to 20 bits */
+#define ZOPT2201_UVB_DATA		0x10 /* LSB first, 13 to 20 bits */
+#define ZOPT2201_UV_COMP_DATA		0x13 /* LSB first, 13 to 20 bits */
+#define ZOPT2201_COMP_DATA		0x16 /* LSB first, 13 to 20 bits */
+#define ZOPT2201_INT_CFG		0x19
+#define ZOPT2201_INT_PST		0x1a
+
+#define ZOPT2201_MAIN_CTRL_LS_MODE	BIT(3) /* 0 .. ALS, 1 .. UV B */
+#define ZOPT2201_MAIN_CTRL_LS_EN	BIT(1)
+
+/* Values for ZOPT2201_LS_MEAS_RATE resolution / bit width */
+#define ZOPT2201_MEAS_RES_20BIT		0 /* takes 400 ms */
+#define ZOPT2201_MEAS_RES_19BIT		1 /* takes 200 ms */
+#define ZOPT2201_MEAS_RES_18BIT		2 /* takes 100 ms, default */
+#define ZOPT2201_MEAS_RES_17BIT		3 /* takes 50 ms */
+#define ZOPT2201_MEAS_RES_16BIT		4 /* takes 25 ms */
+#define ZOPT2201_MEAS_RES_13BIT		5 /* takes 3.125 ms */
+#define ZOPT2201_MEAS_RES_SHIFT		4
+
+/* Values for ZOPT2201_LS_MEAS_RATE measurement rate */
+#define ZOPT2201_MEAS_FREQ_25MS		0
+#define ZOPT2201_MEAS_FREQ_50MS		1
+#define ZOPT2201_MEAS_FREQ_100MS	2 /* default */
+#define ZOPT2201_MEAS_FREQ_200MS	3
+#define ZOPT2201_MEAS_FREQ_500MS	4
+#define ZOPT2201_MEAS_FREQ_1000MS	5
+#define ZOPT2201_MEAS_FREQ_2000MS	6
+
+/* Values for ZOPT2201_LS_GAIN */
+#define ZOPT2201_LS_GAIN_1		0
+#define ZOPT2201_LS_GAIN_3		1
+#define ZOPT2201_LS_GAIN_6		2
+#define ZOPT2201_LS_GAIN_9		3
+#define ZOPT2201_LS_GAIN_18		4
+
+/* Values for ZOPT2201_MAIN_STATUS */
+#define ZOPT2201_MAIN_STATUS_POWERON	BIT(5)
+#define ZOPT2201_MAIN_STATUS_INT	BIT(4)
+#define ZOPT2201_MAIN_STATUS_DRDY	BIT(3)
+
+#define ZOPT2201_PART_NUMBER		0xb2
+
+struct zopt2201_data {
+	struct i2c_client *client;
+	struct mutex lock;
+	u8 gain;
+	u8 res;
+	u8 rate;
+};
+
+static const struct {
+	unsigned int gain; /* gain factor */
+	unsigned int scale; /* micro lux per count */
+} zopt2201_gain_als[] = {
+	{  1, 19200000 },
+	{  3,  6400000 },
+	{  6,  3200000 },
+	{  9,  2133333 },
+	{ 18,  1066666 },
+};
+
+static const struct {
+	unsigned int gain; /* gain factor */
+	unsigned int scale; /* micro W/m2 per count */
+} zopt2201_gain_uvb[] = {
+	{  1, 460800 },
+	{  3, 153600 },
+	{  6,  76800 },
+	{  9,  51200 },
+	{ 18,  25600 },
+};
+
+static const struct {
+	unsigned int bits; /* sensor resolution in bits */
+	unsigned long us; /* measurement time in micro seconds */
+} zopt2201_resolution[] = {
+	{ 20, 400000 },
+	{ 19, 200000 },
+	{ 18, 100000 },
+	{ 17,  50000 },
+	{ 16,  25000 },
+	{ 13,   3125 },
+};
+
+static const struct {
+	unsigned int scale, uscale; /* scale factor as integer + micro */
+	u8 gain; /* gain register value */
+	u8 res; /* resolution register value */
+} zopt2201_scale_als[] = {
+	{ 19, 200000, 0, 5 },
+	{  6, 400000, 1, 5 },
+	{  3, 200000, 2, 5 },
+	{  2, 400000, 0, 4 },
+	{  2, 133333, 3, 5 },
+	{  1, 200000, 0, 3 },
+	{  1,  66666, 4, 5 },
+	{  0, 800000, 1, 4 },
+	{  0, 600000, 0, 2 },
+	{  0, 400000, 2, 4 },
+	{  0, 300000, 0, 1 },
+	{  0, 266666, 3, 4 },
+	{  0, 200000, 2, 3 },
+	{  0, 150000, 0, 0 },
+	{  0, 133333, 4, 4 },
+	{  0, 100000, 2, 2 },
+	{  0,  66666, 4, 3 },
+	{  0,  50000, 2, 1 },
+	{  0,  33333, 4, 2 },
+	{  0,  25000, 2, 0 },
+	{  0,  16666, 4, 1 },
+	{  0,   8333, 4, 0 },
+};
+
+static const struct {
+	unsigned int scale, uscale; /* scale factor as integer + micro */
+	u8 gain; /* gain register value */
+	u8 res; /* resolution register value */
+} zopt2201_scale_uvb[] = {
+	{ 0, 460800, 0, 5 },
+	{ 0, 153600, 1, 5 },
+	{ 0,  76800, 2, 5 },
+	{ 0,  57600, 0, 4 },
+	{ 0,  51200, 3, 5 },
+	{ 0,  28800, 0, 3 },
+	{ 0,  25600, 4, 5 },
+	{ 0,  19200, 1, 4 },
+	{ 0,  14400, 0, 2 },
+	{ 0,   9600, 2, 4 },
+	{ 0,   7200, 0, 1 },
+	{ 0,   6400, 3, 4 },
+	{ 0,   4800, 2, 3 },
+	{ 0,   3600, 0, 0 },
+	{ 0,   3200, 4, 4 },
+	{ 0,   2400, 2, 2 },
+	{ 0,   1600, 4, 3 },
+	{ 0,   1200, 2, 1 },
+	{ 0,    800, 4, 2 },
+	{ 0,    600, 2, 0 },
+	{ 0,    400, 4, 1 },
+	{ 0,    200, 4, 0 },
+};
+
+static int zopt2201_enable_mode(struct zopt2201_data *data, bool uvb_mode)
+{
+	u8 out = ZOPT2201_MAIN_CTRL_LS_EN;
+
+	if (uvb_mode)
+		out |= ZOPT2201_MAIN_CTRL_LS_MODE;
+
+	return i2c_smbus_write_byte_data(data->client, ZOPT2201_MAIN_CTRL, out);
+}
+
+static int zopt2201_read(struct zopt2201_data *data, u8 reg)
+{
+	struct i2c_client *client = data->client;
+	int tries = 10;
+	u8 buf[3];
+	int ret;
+
+	mutex_lock(&data->lock);
+	ret = zopt2201_enable_mode(data, reg == ZOPT2201_UVB_DATA);
+	if (ret < 0)
+		goto fail;
+
+	while (tries--) {
+		unsigned long t = zopt2201_resolution[data->res].us;
+
+		if (t <= 20000)
+			usleep_range(t, t + 1000);
+		else
+			msleep(t / 1000);
+		ret = i2c_smbus_read_byte_data(client, ZOPT2201_MAIN_STATUS);
+		if (ret < 0)
+			goto fail;
+		if (ret & ZOPT2201_MAIN_STATUS_DRDY)
+			break;
+	}
+
+	if (tries < 0) {
+		ret = -ETIMEDOUT;
+		goto fail;
+	}
+
+	ret = i2c_smbus_read_i2c_block_data(client, reg, sizeof(buf), buf);
+	if (ret < 0)
+		goto fail;
+
+	ret = i2c_smbus_write_byte_data(client, ZOPT2201_MAIN_CTRL, 0x00);
+	if (ret < 0)
+		goto fail;
+	mutex_unlock(&data->lock);
+
+	return (buf[2] << 16) | (buf[1] << 8) | buf[0];
+
+fail:
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static const struct iio_chan_spec zopt2201_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.address = ZOPT2201_ALS_DATA,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+	{
+		.type = IIO_INTENSITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_LIGHT_UV,
+		.address = ZOPT2201_UVB_DATA,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+	{
+		.type = IIO_UVINDEX,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+	},
+};
+
+static int zopt2201_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct zopt2201_data *data = iio_priv(indio_dev);
+	u64 tmp;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = zopt2201_read(data, chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_PROCESSED:
+		ret = zopt2201_read(data, ZOPT2201_UVB_DATA);
+		if (ret < 0)
+			return ret;
+		*val = ret * 18 *
+			(1 << (20 - zopt2201_resolution[data->res].bits)) /
+			zopt2201_gain_uvb[data->gain].gain;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->address) {
+		case ZOPT2201_ALS_DATA:
+			*val = zopt2201_gain_als[data->gain].scale;
+			break;
+		case ZOPT2201_UVB_DATA:
+			*val = zopt2201_gain_uvb[data->gain].scale;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		*val2 = 1000000;
+		*val2 *= (1 << (zopt2201_resolution[data->res].bits - 13));
+		tmp = div_s64(*val * 1000000ULL, *val2);
+		*val = div_s64_rem(tmp, 1000000, val2);
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_INT_TIME:
+		*val = 0;
+		*val2 = zopt2201_resolution[data->res].us;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int zopt2201_set_resolution(struct zopt2201_data *data, u8 res)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, ZOPT2201_LS_MEAS_RATE,
+					(res << ZOPT2201_MEAS_RES_SHIFT) |
+					data->rate);
+	if (ret < 0)
+		return ret;
+
+	data->res = res;
+
+	return 0;
+}
+
+static int zopt2201_write_resolution(struct zopt2201_data *data,
+				     int val, int val2)
+{
+	int i, ret;
+
+	if (val != 0)
+		return -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_resolution); i++)
+		if (val2 == zopt2201_resolution[i].us) {
+			mutex_lock(&data->lock);
+			ret = zopt2201_set_resolution(data, i);
+			mutex_unlock(&data->lock);
+			return ret;
+		}
+
+	return -EINVAL;
+}
+
+static int zopt2201_set_gain(struct zopt2201_data *data, u8 gain)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, ZOPT2201_LS_GAIN, gain);
+	if (ret < 0)
+		return ret;
+
+	data->gain = gain;
+
+	return 0;
+}
+
+static int zopt2201_write_scale_als_by_idx(struct zopt2201_data *data, int idx)
+{
+	int ret;
+
+	mutex_lock(&data->lock);
+	ret = zopt2201_set_resolution(data, zopt2201_scale_als[idx].res);
+	if (ret < 0)
+		goto unlock;
+
+	ret = zopt2201_set_gain(data, zopt2201_scale_als[idx].gain);
+
+unlock:
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static int zopt2201_write_scale_als(struct zopt2201_data *data,
+				     int val, int val2)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_als); i++)
+		if (val == zopt2201_scale_als[i].scale &&
+		    val2 == zopt2201_scale_als[i].uscale) {
+			return zopt2201_write_scale_als_by_idx(data, i);
+		}
+
+	return -EINVAL;
+}
+
+static int zopt2201_write_scale_uvb_by_idx(struct zopt2201_data *data, int idx)
+{
+	int ret;
+
+	mutex_lock(&data->lock);
+	ret = zopt2201_set_resolution(data, zopt2201_scale_als[idx].res);
+	if (ret < 0)
+		goto unlock;
+
+	ret = zopt2201_set_gain(data, zopt2201_scale_als[idx].gain);
+
+unlock:
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static int zopt2201_write_scale_uvb(struct zopt2201_data *data,
+				     int val, int val2)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_uvb); i++)
+		if (val == zopt2201_scale_uvb[i].scale &&
+		    val2 == zopt2201_scale_uvb[i].uscale)
+			return zopt2201_write_scale_uvb_by_idx(data, i);
+
+	return -EINVAL;
+}
+
+static int zopt2201_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int val, int val2, long mask)
+{
+	struct zopt2201_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		return zopt2201_write_resolution(data, val, val2);
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->address) {
+		case ZOPT2201_ALS_DATA:
+			return zopt2201_write_scale_als(data, val, val2);
+		case ZOPT2201_UVB_DATA:
+			return zopt2201_write_scale_uvb(data, val, val2);
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t zopt2201_show_int_time_available(struct device *dev,
+						struct device_attribute *attr,
+						char *buf)
+{
+	size_t len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_resolution); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06lu ",
+				 zopt2201_resolution[i].us);
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static IIO_DEV_ATTR_INT_TIME_AVAIL(zopt2201_show_int_time_available);
+
+static ssize_t zopt2201_show_als_scale_avail(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	ssize_t len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_als); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
+				 zopt2201_scale_als[i].scale,
+				 zopt2201_scale_als[i].uscale);
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static ssize_t zopt2201_show_uvb_scale_avail(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	ssize_t len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(zopt2201_scale_uvb); i++)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
+				 zopt2201_scale_uvb[i].scale,
+				 zopt2201_scale_uvb[i].uscale);
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(in_illuminance_scale_available, 0444,
+		       zopt2201_show_als_scale_avail, NULL, 0);
+static IIO_DEVICE_ATTR(in_intensity_uv_scale_available, 0444,
+		       zopt2201_show_uvb_scale_avail, NULL, 0);
+
+static struct attribute *zopt2201_attributes[] = {
+	&iio_dev_attr_integration_time_available.dev_attr.attr,
+	&iio_dev_attr_in_illuminance_scale_available.dev_attr.attr,
+	&iio_dev_attr_in_intensity_uv_scale_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group zopt2201_attribute_group = {
+	.attrs = zopt2201_attributes,
+};
+
+static const struct iio_info zopt2201_info = {
+	.read_raw = zopt2201_read_raw,
+	.write_raw = zopt2201_write_raw,
+	.attrs = &zopt2201_attribute_group,
+};
+
+static int zopt2201_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct zopt2201_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+		return -EOPNOTSUPP;
+
+	ret = i2c_smbus_read_byte_data(client, ZOPT2201_PART_ID);
+	if (ret < 0)
+		return ret;
+	if (ret != ZOPT2201_PART_NUMBER)
+		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 = &zopt2201_info;
+	indio_dev->channels = zopt2201_channels;
+	indio_dev->num_channels = ARRAY_SIZE(zopt2201_channels);
+	indio_dev->name = ZOPT2201_DRV_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	data->rate = ZOPT2201_MEAS_FREQ_100MS;
+	ret = zopt2201_set_resolution(data, ZOPT2201_MEAS_RES_18BIT);
+	if (ret < 0)
+		return ret;
+
+	ret = zopt2201_set_gain(data, ZOPT2201_LS_GAIN_3);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id zopt2201_id[] = {
+	{ "zopt2201", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, zopt2201_id);
+
+static struct i2c_driver zopt2201_driver = {
+	.driver = {
+		.name   = ZOPT2201_DRV_NAME,
+	},
+	.probe  = zopt2201_probe,
+	.id_table = zopt2201_id,
+};
+
+module_i2c_driver(zopt2201_driver);
+
+MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("IDT ZOPT2201 ambient light and UV B sensor driver");
+MODULE_LICENSE("GPL");