--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * IIO driver for the light sensor ISL76682.
+ * ISL76682 is Ambient Light Sensor
+ *
+ * Copyright (c) 2023 Marek Vasut <marex@denx.de>
+ */
+
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+#include <linux/iio/iio.h>
+
+#define ISL76682_REG_COMMAND 0x00
+
+#define ISL76682_COMMAND_EN BIT(7)
+#define ISL76682_COMMAND_MODE_CONTINUOUS BIT(6)
+#define ISL76682_COMMAND_LIGHT_IR BIT(5)
+
+#define ISL76682_COMMAND_RANGE_LUX_1K 0x0
+#define ISL76682_COMMAND_RANGE_LUX_4K 0x1
+#define ISL76682_COMMAND_RANGE_LUX_16K 0x2
+#define ISL76682_COMMAND_RANGE_LUX_64K 0x3
+#define ISL76682_COMMAND_RANGE_LUX_MASK GENMASK(1, 0)
+
+#define ISL76682_REG_ALSIR_L 0x01
+
+#define ISL76682_REG_ALSIR_U 0x02
+
+#define ISL76682_NUM_REGS (ISL76682_REG_ALSIR_U + 1)
+
+#define ISL76682_CONV_TIME_MS 100
+#define ISL76682_INT_TIME_US 90000
+
+#define ISL76682_ADC_MAX (BIT(16) - 1)
+
+struct isl76682_chip {
+ /*
+ * Lock to synchronize access to device command register
+ * and the content of range variable below.
+ */
+ struct mutex lock;
+ struct regmap *regmap;
+ u8 range;
+ u8 command;
+};
+
+struct isl76682_range {
+ u8 range;
+ u32 als;
+ u32 ir;
+};
+
+static struct isl76682_range isl76682_range_table[] = {
+ { ISL76682_COMMAND_RANGE_LUX_1K, 15000, 10500 },
+ { ISL76682_COMMAND_RANGE_LUX_4K, 60000, 42000 },
+ { ISL76682_COMMAND_RANGE_LUX_16K, 240000, 168000 },
+ { ISL76682_COMMAND_RANGE_LUX_64K, 960000, 673000 }
+};
+
+static int isl76682_get(struct isl76682_chip *chip, bool mode_ir, int *data)
+{
+ u8 command;
+ int ret;
+
+ command = ISL76682_COMMAND_EN | ISL76682_COMMAND_MODE_CONTINUOUS |
+ chip->range;
+
+ if (mode_ir)
+ command |= ISL76682_COMMAND_LIGHT_IR;
+
+ if (command != chip->command) {
+ ret = regmap_write(chip->regmap, ISL76682_REG_COMMAND, command);
+ if (ret)
+ return ret;
+
+ /* Need to wait for conversion time if ALS/IR mode enabled */
+ msleep(ISL76682_CONV_TIME_MS);
+
+ chip->command = command;
+ }
+
+ ret = regmap_bulk_read(chip->regmap, ISL76682_REG_ALSIR_L, data, 2);
+ *data &= ISL76682_ADC_MAX;
+ return ret;
+}
+
+static int isl76682_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct isl76682_chip *chip = iio_priv(indio_dev);
+ int i;
+
+ if (mask != IIO_CHAN_INFO_SCALE)
+ return -EINVAL;
+
+ if (val != 0)
+ return -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(isl76682_range_table); i++) {
+ if (chan->type == IIO_LIGHT && val2 != isl76682_range_table[i].als)
+ continue;
+ if (chan->type == IIO_INTENSITY && val2 != isl76682_range_table[i].ir)
+ continue;
+
+ scoped_guard(mutex, &chip->lock)
+ chip->range = isl76682_range_table[i].range;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int isl76682_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct isl76682_chip *chip = iio_priv(indio_dev);
+ int ret;
+ int i;
+
+ guard(mutex)(&chip->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ ret = isl76682_get(chip, false, val);
+ return (ret < 0) ? ret : IIO_VAL_INT;
+ case IIO_INTENSITY:
+ ret = isl76682_get(chip, true, val);
+ return (ret < 0) ? ret : IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ return -EINVAL;
+ case IIO_CHAN_INFO_SCALE:
+ for (i = 0; i < ARRAY_SIZE(isl76682_range_table); i++) {
+ if (chip->range != isl76682_range_table[i].range)
+ continue;
+
+ *val = 0;
+ switch (chan->type) {
+ case IIO_LIGHT:
+ *val2 = isl76682_range_table[i].als;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_INTENSITY:
+ *val2 = isl76682_range_table[i].ir;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+ }
+ return -EINVAL;
+ case IIO_CHAN_INFO_INT_TIME:
+ *val = 0;
+ *val2 = ISL76682_INT_TIME_US;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int illuminance_scale_available[] = {
+ 0, 15000,
+ 0, 60000,
+ 0, 240000,
+ 0, 960000,
+};
+
+static int intensity_scale_available[] = {
+ 0, 10500,
+ 0, 42000,
+ 0, 168000,
+ 0, 673000,
+};
+
+static int isl76682_read_avail(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_SCALE:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ *vals = illuminance_scale_available;
+ *length = ARRAY_SIZE(illuminance_scale_available);
+ *type = IIO_VAL_INT_PLUS_MICRO;
+ return IIO_AVAIL_LIST;
+ case IIO_INTENSITY:
+ *vals = intensity_scale_available;
+ *length = ARRAY_SIZE(intensity_scale_available);
+ *type = IIO_VAL_INT_PLUS_MICRO;
+ return IIO_AVAIL_LIST;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_chan_spec isl76682_channels[] = {
+ {
+ .type = IIO_LIGHT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+ }, {
+ .type = IIO_INTENSITY,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
+ }
+};
+
+static const struct iio_info isl76682_info = {
+ .read_avail = isl76682_read_avail,
+ .read_raw = isl76682_read_raw,
+ .write_raw = isl76682_write_raw,
+};
+
+static int isl76682_clear_configure_reg(struct isl76682_chip *chip)
+{
+ struct device *dev = regmap_get_device(chip->regmap);
+ int ret;
+
+ ret = regmap_write(chip->regmap, ISL76682_REG_COMMAND, 0x0);
+ if (ret < 0)
+ dev_err(dev, "Error %d clearing the CONFIGURE register\n", ret);
+
+ /*
+ * In the success case, the command register was zeroed out.
+ *
+ * In the error case, we do not know in which state the command
+ * register is, so we assume it is zeroed out, so that it would
+ * be reprogrammed at the next data read out, and at that time
+ * we hope it would be reprogrammed successfully. That is very
+ * much a best effort approach.
+ */
+ chip->command = 0;
+
+ return ret;
+}
+
+static void isl76682_reset_action(void *chip)
+{
+ isl76682_clear_configure_reg(chip);
+}
+
+static bool isl76682_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case ISL76682_REG_ALSIR_L:
+ case ISL76682_REG_ALSIR_U:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static const struct regmap_config isl76682_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .volatile_reg = isl76682_is_volatile_reg,
+ .max_register = ISL76682_NUM_REGS - 1,
+ .num_reg_defaults_raw = ISL76682_NUM_REGS,
+ .cache_type = REGCACHE_FLAT,
+};
+
+static int isl76682_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct isl76682_chip *chip;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ chip = iio_priv(indio_dev);
+
+ mutex_init(&chip->lock);
+
+ chip->regmap = devm_regmap_init_i2c(client, &isl76682_regmap_config);
+ ret = PTR_ERR_OR_ZERO(chip->regmap);
+ if (ret)
+ return dev_err_probe(dev, ret, "Error initializing regmap\n");
+
+ chip->range = ISL76682_COMMAND_RANGE_LUX_1K;
+
+ ret = isl76682_clear_configure_reg(chip);
+ if (ret < 0)
+ return ret;
+
+ ret = devm_add_action_or_reset(dev, isl76682_reset_action, chip);
+ if (ret)
+ return ret;
+
+ indio_dev->info = &isl76682_info;
+ indio_dev->channels = isl76682_channels;
+ indio_dev->num_channels = ARRAY_SIZE(isl76682_channels);
+ indio_dev->name = "isl76682";
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct i2c_device_id isl76682_id[] = {
+ { "isl76682" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, isl76682_id);
+
+static const struct of_device_id isl76682_of_match[] = {
+ { .compatible = "isil,isl76682" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, isl76682_of_match);
+
+static struct i2c_driver isl76682_driver = {
+ .driver = {
+ .name = "isl76682",
+ .of_match_table = isl76682_of_match,
+ },
+ .probe = isl76682_probe,
+ .id_table = isl76682_id,
+};
+module_i2c_driver(isl76682_driver);
+
+MODULE_DESCRIPTION("ISL76682 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
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