iio: light: Add support for ltrf216a sensor

Add initial support for ltrf216a ambient light sensor.

Datasheet: https://gitlab.collabora.com/shreeya/iio/-/blob/master/LTRF216A.pdf
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Co-developed-by: Zhigang Shi <Zhigang.Shi@liteon.com>
Signed-off-by: Zhigang Shi <Zhigang.Shi@liteon.com>
Co-developed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Shreeya Patel <shreeya.patel@collabora.com>
Link: https://lore.kernel.org/r/20220725104050.491396-3-shreeya.patel@collabora.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 537 insertions, 0 deletions

diff --git a/drivers/iio/light/ltrf216a.c b/drivers/iio/light/ltrf216a.c
new file mode 100644
index 000000000000..e6e24e70d2b9
--- /dev/null
+++ b/drivers/iio/light/ltrf216a.c
@@ -0,0 +1,537 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LTRF216A Ambient Light Sensor
+ *
+ * Copyright (C) 2022 Collabora, Ltd.
+ * Author: Shreeya Patel <shreeya.patel@collabora.com>
+ *
+ * Copyright (C) 2021 Lite-On Technology Corp (Singapore)
+ * Author: Shi Zhigang <Zhigang.Shi@liteon.com>
+ *
+ * IIO driver for LTRF216A (7-bit I2C slave address 0x53).
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+
+#include <linux/iio/iio.h>
+
+#include <asm/unaligned.h>
+
+#define LTRF216A_ALS_RESET_MASK		BIT(4)
+#define LTRF216A_ALS_DATA_STATUS	BIT(3)
+#define LTRF216A_ALS_ENABLE_MASK	BIT(1)
+#define LTRF216A_MAIN_CTRL		0x00
+#define LTRF216A_ALS_MEAS_RES		0x04
+#define LTRF216A_ALS_GAIN		0x05
+#define LTRF216A_PART_ID		0x06
+#define LTRF216A_MAIN_STATUS		0x07
+#define LTRF216A_ALS_CLEAR_DATA_0	0x0a
+#define LTRF216A_ALS_CLEAR_DATA_1	0x0b
+#define LTRF216A_ALS_CLEAR_DATA_2	0x0c
+#define LTRF216A_ALS_DATA_0		0x0d
+#define LTRF216A_ALS_DATA_1		0x0e
+#define LTRF216A_ALS_DATA_2		0x0f
+#define LTRF216A_INT_CFG		0x19
+#define LTRF216A_INT_PST		0x1a
+#define LTRF216A_ALS_THRES_UP_0		0x21
+#define LTRF216A_ALS_THRES_UP_1		0x22
+#define LTRF216A_ALS_THRES_UP_2		0x23
+#define LTRF216A_ALS_THRES_LOW_0	0x24
+#define LTRF216A_ALS_THRES_LOW_1	0x25
+#define LTRF216A_ALS_THRES_LOW_2	0x26
+#define LTRF216A_ALS_READ_DATA_DELAY_US	20000
+
+static const int ltrf216a_int_time_available[][2] = {
+	{ 0, 400000 },
+	{ 0, 200000 },
+	{ 0, 100000 },
+	{ 0,  50000 },
+	{ 0,  25000 },
+};
+
+static const int ltrf216a_int_time_reg[][2] = {
+	{ 400, 0x03 },
+	{ 200, 0x13 },
+	{ 100, 0x22 },
+	{  50, 0x31 },
+	{  25, 0x40 },
+};
+
+/*
+ * Window Factor is needed when the device is under Window glass
+ * with coated tinted ink. This is to compensate for the light loss
+ * due to the lower transmission rate of the window glass and helps
+ * in calculating lux.
+ */
+#define LTRF216A_WIN_FAC	1
+
+struct ltrf216a_data {
+	struct regmap *regmap;
+	struct i2c_client *client;
+	u32 int_time;
+	u16 int_time_fac;
+	u8 als_gain_fac;
+	/*
+	 * Protects regmap accesses and makes sure integration time
+	 * remains constant during the measurement of lux.
+	 */
+	struct mutex lock;
+};
+
+static const struct iio_chan_spec ltrf216a_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_PROCESSED) |
+			BIT(IIO_CHAN_INFO_INT_TIME),
+		.info_mask_separate_available =
+			BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+};
+
+static void ltrf216a_reset(struct iio_dev *indio_dev)
+{
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+
+	/* reset sensor, chip fails to respond to this, so ignore any errors */
+	regmap_write(data->regmap, LTRF216A_MAIN_CTRL, LTRF216A_ALS_RESET_MASK);
+
+	/* reset time */
+	usleep_range(1000, 2000);
+}
+
+static int ltrf216a_enable(struct iio_dev *indio_dev)
+{
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+	struct device *dev = &data->client->dev;
+	int ret;
+
+	/* enable sensor */
+	ret = regmap_set_bits(data->regmap,
+			      LTRF216A_MAIN_CTRL, LTRF216A_ALS_ENABLE_MASK);
+	if (ret) {
+		dev_err(dev, "failed to enable sensor: %d\n", ret);
+		return ret;
+	}
+
+	/* sleep for one integration cycle after enabling the device */
+	msleep(ltrf216a_int_time_reg[0][0]);
+
+	return 0;
+}
+
+static int ltrf216a_disable(struct iio_dev *indio_dev)
+{
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+	struct device *dev = &data->client->dev;
+	int ret;
+
+	ret = regmap_write(data->regmap, LTRF216A_MAIN_CTRL, 0);
+	if (ret)
+		dev_err(dev, "failed to disable sensor: %d\n", ret);
+
+	return ret;
+}
+
+static void ltrf216a_cleanup(void *data)
+{
+	struct iio_dev *indio_dev = data;
+
+	ltrf216a_disable(indio_dev);
+}
+
+static int ltrf216a_set_int_time(struct ltrf216a_data *data, int itime)
+{
+	struct device *dev = &data->client->dev;
+	unsigned int i;
+	u8 reg_val;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(ltrf216a_int_time_available); i++) {
+		if (ltrf216a_int_time_available[i][1] == itime)
+			break;
+	}
+	if (i == ARRAY_SIZE(ltrf216a_int_time_available))
+		return -EINVAL;
+
+	reg_val = ltrf216a_int_time_reg[i][1];
+
+	ret = regmap_write(data->regmap, LTRF216A_ALS_MEAS_RES, reg_val);
+	if (ret) {
+		dev_err(dev, "failed to set integration time: %d\n", ret);
+		return ret;
+	}
+
+	data->int_time_fac = ltrf216a_int_time_reg[i][0];
+	data->int_time = itime;
+
+	return 0;
+}
+
+static int ltrf216a_get_int_time(struct ltrf216a_data *data,
+				 int *val, int *val2)
+{
+	*val = 0;
+	*val2 = data->int_time;
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ltrf216a_set_power_state(struct ltrf216a_data *data, bool on)
+{
+	struct device *dev = &data->client->dev;
+	int ret = 0;
+
+	if (on) {
+		ret = pm_runtime_resume_and_get(dev);
+		if (ret) {
+			dev_err(dev, "failed to resume runtime PM: %d\n", ret);
+			return ret;
+		}
+	} else {
+		pm_runtime_mark_last_busy(dev);
+		pm_runtime_put_autosuspend(dev);
+	}
+
+	return ret;
+}
+
+static int ltrf216a_read_data(struct ltrf216a_data *data, u8 addr)
+{
+	struct device *dev = &data->client->dev;
+	int ret, val;
+	u8 buf[3];
+
+	ret = regmap_read_poll_timeout(data->regmap, LTRF216A_MAIN_STATUS,
+				       val, val & LTRF216A_ALS_DATA_STATUS,
+				       LTRF216A_ALS_READ_DATA_DELAY_US,
+				       LTRF216A_ALS_READ_DATA_DELAY_US * 50);
+	if (ret) {
+		dev_err(dev, "failed to wait for measurement data: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_bulk_read(data->regmap, addr, buf, sizeof(buf));
+	if (ret) {
+		dev_err(dev, "failed to read measurement data: %d\n", ret);
+		return ret;
+	}
+
+	return get_unaligned_le24(&buf[0]);
+}
+
+static int ltrf216a_get_lux(struct ltrf216a_data *data)
+{
+	int ret, greendata;
+	u64 lux, div;
+
+	ret = ltrf216a_set_power_state(data, true);
+	if (ret)
+		return ret;
+
+	greendata = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
+	if (greendata < 0)
+		return greendata;
+
+	ltrf216a_set_power_state(data, false);
+
+	lux = greendata * 45 * LTRF216A_WIN_FAC * 100;
+	div = data->als_gain_fac * data->int_time_fac * 100;
+
+	return div_u64(lux, div);
+}
+
+static int ltrf216a_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int *val,
+			     int *val2, long mask)
+{
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		mutex_lock(&data->lock);
+		ret = ltrf216a_get_lux(data);
+		mutex_unlock(&data->lock);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_INT_TIME:
+		mutex_lock(&data->lock);
+		ret = ltrf216a_get_int_time(data, val, val2);
+		mutex_unlock(&data->lock);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ltrf216a_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan, int val,
+			      int val2, long mask)
+{
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		if (val != 0)
+			return -EINVAL;
+		mutex_lock(&data->lock);
+		ret = ltrf216a_set_int_time(data, val2);
+		mutex_unlock(&data->lock);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ltrf216a_read_available(struct iio_dev *indio_dev,
+				   struct iio_chan_spec const *chan,
+				   const int **vals, int *type, int *length,
+				   long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		*length = ARRAY_SIZE(ltrf216a_int_time_available) * 2;
+		*vals = (const int *)ltrf216a_int_time_available;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ltrf216a_info = {
+	.read_raw = ltrf216a_read_raw,
+	.write_raw = ltrf216a_write_raw,
+	.read_avail = ltrf216a_read_available,
+};
+
+static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LTRF216A_MAIN_CTRL:
+	case LTRF216A_ALS_MEAS_RES:
+	case LTRF216A_ALS_GAIN:
+	case LTRF216A_PART_ID:
+	case LTRF216A_MAIN_STATUS:
+	case LTRF216A_ALS_CLEAR_DATA_0:
+	case LTRF216A_ALS_CLEAR_DATA_1:
+	case LTRF216A_ALS_CLEAR_DATA_2:
+	case LTRF216A_ALS_DATA_0:
+	case LTRF216A_ALS_DATA_1:
+	case LTRF216A_ALS_DATA_2:
+	case LTRF216A_INT_CFG:
+	case LTRF216A_INT_PST:
+	case LTRF216A_ALS_THRES_UP_0:
+	case LTRF216A_ALS_THRES_UP_1:
+	case LTRF216A_ALS_THRES_UP_2:
+	case LTRF216A_ALS_THRES_LOW_0:
+	case LTRF216A_ALS_THRES_LOW_1:
+	case LTRF216A_ALS_THRES_LOW_2:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LTRF216A_MAIN_CTRL:
+	case LTRF216A_ALS_MEAS_RES:
+	case LTRF216A_ALS_GAIN:
+	case LTRF216A_INT_CFG:
+	case LTRF216A_INT_PST:
+	case LTRF216A_ALS_THRES_UP_0:
+	case LTRF216A_ALS_THRES_UP_1:
+	case LTRF216A_ALS_THRES_UP_2:
+	case LTRF216A_ALS_THRES_LOW_0:
+	case LTRF216A_ALS_THRES_LOW_1:
+	case LTRF216A_ALS_THRES_LOW_2:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LTRF216A_MAIN_STATUS:
+	case LTRF216A_ALS_CLEAR_DATA_0:
+	case LTRF216A_ALS_CLEAR_DATA_1:
+	case LTRF216A_ALS_CLEAR_DATA_2:
+	case LTRF216A_ALS_DATA_0:
+	case LTRF216A_ALS_DATA_1:
+	case LTRF216A_ALS_DATA_2:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool ltrf216a_precious_reg(struct device *dev, unsigned int reg)
+{
+	return reg == LTRF216A_MAIN_STATUS;
+}
+
+static const struct regmap_config ltrf216a_regmap_config = {
+	.name = "ltrf216a",
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_RBTREE,
+	.max_register = LTRF216A_ALS_THRES_LOW_2,
+	.readable_reg = ltrf216a_readable_reg,
+	.writeable_reg = ltrf216a_writable_reg,
+	.volatile_reg = ltrf216a_volatile_reg,
+	.precious_reg = ltrf216a_precious_reg,
+	.disable_locking = true,
+};
+
+static int ltrf216a_probe(struct i2c_client *client)
+{
+	struct ltrf216a_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+
+	data->regmap = devm_regmap_init_i2c(client, &ltrf216a_regmap_config);
+	if (IS_ERR(data->regmap))
+		return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
+				     "regmap initialization failed\n");
+
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	mutex_init(&data->lock);
+
+	indio_dev->info = &ltrf216a_info;
+	indio_dev->name = "ltrf216a";
+	indio_dev->channels = ltrf216a_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ltrf216a_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = pm_runtime_set_active(&client->dev);
+	if (ret)
+		return ret;
+
+	/* reset sensor, chip fails to respond to this, so ignore any errors */
+	ltrf216a_reset(indio_dev);
+
+	ret = regmap_reinit_cache(data->regmap, &ltrf216a_regmap_config);
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to reinit regmap cache\n");
+
+	ret = ltrf216a_enable(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(&client->dev, ltrf216a_cleanup,
+				       indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_pm_runtime_enable(&client->dev);
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to enable runtime PM\n");
+
+	pm_runtime_set_autosuspend_delay(&client->dev, 1000);
+	pm_runtime_use_autosuspend(&client->dev);
+
+	data->int_time = 100000;
+	data->int_time_fac = 100;
+	data->als_gain_fac = 3;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int ltrf216a_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+	int ret;
+
+	ret = ltrf216a_disable(indio_dev);
+	if (ret)
+		return ret;
+
+	regcache_cache_only(data->regmap, true);
+
+	return 0;
+}
+
+static int ltrf216a_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+	int ret;
+
+	regcache_cache_only(data->regmap, false);
+	regcache_mark_dirty(data->regmap);
+	ret = regcache_sync(data->regmap);
+	if (ret)
+		goto cache_only;
+
+	ret = ltrf216a_enable(indio_dev);
+	if (ret)
+		goto cache_only;
+
+	return 0;
+
+cache_only:
+	regcache_cache_only(data->regmap, true);
+
+	return ret;
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_runtime_suspend,
+				 ltrf216a_runtime_resume, NULL);
+
+static const struct i2c_device_id ltrf216a_id[] = {
+	{ "ltrf216a" },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
+
+static const struct of_device_id ltrf216a_of_match[] = {
+	{ .compatible = "liteon,ltrf216a" },
+	{ .compatible = "ltr,ltrf216a" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ltrf216a_of_match);
+
+static struct i2c_driver ltrf216a_driver = {
+	.driver = {
+		.name = "ltrf216a",
+		.pm = pm_ptr(&ltrf216a_pm_ops),
+		.of_match_table = ltrf216a_of_match,
+	},
+	.probe_new = ltrf216a_probe,
+	.id_table = ltrf216a_id,
+};
+module_i2c_driver(ltrf216a_driver);
+
+MODULE_AUTHOR("Shreeya Patel <shreeya.patel@collabora.com>");
+MODULE_AUTHOR("Shi Zhigang <Zhigang.Shi@liteon.com>");
+MODULE_DESCRIPTION("LTRF216A ambient light sensor driver");
+MODULE_LICENSE("GPL");