--- /dev/null
+// 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, <rf216a_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 = <rf216a_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, <rf216a_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(<rf216a_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");
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