--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * lv0104cs.c: LV0104CS Ambient Light Sensor Driver
+ *
+ * Copyright (C) 2018
+ * Author: Jeff LaBundy <jeff@labundy.com>
+ *
+ * 7-bit I2C slave address: 0x13
+ *
+ * Link to data sheet: http://www.onsemi.com/pub/Collateral/LV0104CS-D.PDF
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define LV0104CS_REGVAL_MEASURE 0xE0
+#define LV0104CS_REGVAL_SLEEP 0x00
+
+#define LV0104CS_SCALE_0_25X 0
+#define LV0104CS_SCALE_1X 1
+#define LV0104CS_SCALE_2X 2
+#define LV0104CS_SCALE_8X 3
+#define LV0104CS_SCALE_SHIFT 3
+
+#define LV0104CS_INTEG_12_5MS 0
+#define LV0104CS_INTEG_100MS 1
+#define LV0104CS_INTEG_200MS 2
+#define LV0104CS_INTEG_SHIFT 1
+
+#define LV0104CS_CALIBSCALE_UNITY 31
+
+struct lv0104cs_private {
+ struct i2c_client *client;
+ struct mutex lock;
+ u8 calibscale;
+ u8 scale;
+ u8 int_time;
+};
+
+struct lv0104cs_mapping {
+ int val;
+ int val2;
+ u8 regval;
+};
+
+static const struct lv0104cs_mapping lv0104cs_calibscales[] = {
+ { 0, 666666, 0x81 },
+ { 0, 800000, 0x82 },
+ { 0, 857142, 0x83 },
+ { 0, 888888, 0x84 },
+ { 0, 909090, 0x85 },
+ { 0, 923076, 0x86 },
+ { 0, 933333, 0x87 },
+ { 0, 941176, 0x88 },
+ { 0, 947368, 0x89 },
+ { 0, 952380, 0x8A },
+ { 0, 956521, 0x8B },
+ { 0, 960000, 0x8C },
+ { 0, 962962, 0x8D },
+ { 0, 965517, 0x8E },
+ { 0, 967741, 0x8F },
+ { 0, 969696, 0x90 },
+ { 0, 971428, 0x91 },
+ { 0, 972972, 0x92 },
+ { 0, 974358, 0x93 },
+ { 0, 975609, 0x94 },
+ { 0, 976744, 0x95 },
+ { 0, 977777, 0x96 },
+ { 0, 978723, 0x97 },
+ { 0, 979591, 0x98 },
+ { 0, 980392, 0x99 },
+ { 0, 981132, 0x9A },
+ { 0, 981818, 0x9B },
+ { 0, 982456, 0x9C },
+ { 0, 983050, 0x9D },
+ { 0, 983606, 0x9E },
+ { 0, 984126, 0x9F },
+ { 1, 0, 0x80 },
+ { 1, 16129, 0xBF },
+ { 1, 16666, 0xBE },
+ { 1, 17241, 0xBD },
+ { 1, 17857, 0xBC },
+ { 1, 18518, 0xBB },
+ { 1, 19230, 0xBA },
+ { 1, 20000, 0xB9 },
+ { 1, 20833, 0xB8 },
+ { 1, 21739, 0xB7 },
+ { 1, 22727, 0xB6 },
+ { 1, 23809, 0xB5 },
+ { 1, 24999, 0xB4 },
+ { 1, 26315, 0xB3 },
+ { 1, 27777, 0xB2 },
+ { 1, 29411, 0xB1 },
+ { 1, 31250, 0xB0 },
+ { 1, 33333, 0xAF },
+ { 1, 35714, 0xAE },
+ { 1, 38461, 0xAD },
+ { 1, 41666, 0xAC },
+ { 1, 45454, 0xAB },
+ { 1, 50000, 0xAA },
+ { 1, 55555, 0xA9 },
+ { 1, 62500, 0xA8 },
+ { 1, 71428, 0xA7 },
+ { 1, 83333, 0xA6 },
+ { 1, 100000, 0xA5 },
+ { 1, 125000, 0xA4 },
+ { 1, 166666, 0xA3 },
+ { 1, 250000, 0xA2 },
+ { 1, 500000, 0xA1 },
+};
+
+static const struct lv0104cs_mapping lv0104cs_scales[] = {
+ { 0, 250000, LV0104CS_SCALE_0_25X << LV0104CS_SCALE_SHIFT },
+ { 1, 0, LV0104CS_SCALE_1X << LV0104CS_SCALE_SHIFT },
+ { 2, 0, LV0104CS_SCALE_2X << LV0104CS_SCALE_SHIFT },
+ { 8, 0, LV0104CS_SCALE_8X << LV0104CS_SCALE_SHIFT },
+};
+
+static const struct lv0104cs_mapping lv0104cs_int_times[] = {
+ { 0, 12500, LV0104CS_INTEG_12_5MS << LV0104CS_INTEG_SHIFT },
+ { 0, 100000, LV0104CS_INTEG_100MS << LV0104CS_INTEG_SHIFT },
+ { 0, 200000, LV0104CS_INTEG_200MS << LV0104CS_INTEG_SHIFT },
+};
+
+static int lv0104cs_write_reg(struct i2c_client *client, u8 regval)
+{
+ int ret;
+
+ ret = i2c_master_send(client, (char *)®val, sizeof(regval));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(regval))
+ return -EIO;
+
+ return 0;
+}
+
+static int lv0104cs_read_adc(struct i2c_client *client, u16 *adc_output)
+{
+ __be16 regval;
+ int ret;
+
+ ret = i2c_master_recv(client, (char *)®val, sizeof(regval));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(regval))
+ return -EIO;
+
+ *adc_output = be16_to_cpu(regval);
+
+ return 0;
+}
+
+static int lv0104cs_get_lux(struct lv0104cs_private *lv0104cs,
+ int *val, int *val2)
+{
+ u8 regval = LV0104CS_REGVAL_MEASURE;
+ u16 adc_output;
+ int ret;
+
+ regval |= lv0104cs_scales[lv0104cs->scale].regval;
+ regval |= lv0104cs_int_times[lv0104cs->int_time].regval;
+ ret = lv0104cs_write_reg(lv0104cs->client, regval);
+ if (ret)
+ return ret;
+
+ /* wait for integration time to pass (with margin) */
+ switch (lv0104cs->int_time) {
+ case LV0104CS_INTEG_12_5MS:
+ msleep(50);
+ break;
+
+ case LV0104CS_INTEG_100MS:
+ msleep(150);
+ break;
+
+ case LV0104CS_INTEG_200MS:
+ msleep(250);
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ ret = lv0104cs_read_adc(lv0104cs->client, &adc_output);
+ if (ret)
+ return ret;
+
+ ret = lv0104cs_write_reg(lv0104cs->client, LV0104CS_REGVAL_SLEEP);
+ if (ret)
+ return ret;
+
+ /* convert ADC output to lux */
+ switch (lv0104cs->scale) {
+ case LV0104CS_SCALE_0_25X:
+ *val = adc_output * 4;
+ *val2 = 0;
+ return 0;
+
+ case LV0104CS_SCALE_1X:
+ *val = adc_output;
+ *val2 = 0;
+ return 0;
+
+ case LV0104CS_SCALE_2X:
+ *val = adc_output / 2;
+ *val2 = (adc_output % 2) * 500000;
+ return 0;
+
+ case LV0104CS_SCALE_8X:
+ *val = adc_output / 8;
+ *val2 = (adc_output % 8) * 125000;
+ return 0;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int lv0104cs_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct lv0104cs_private *lv0104cs = iio_priv(indio_dev);
+ int ret;
+
+ if (chan->type != IIO_LIGHT)
+ return -EINVAL;
+
+ mutex_lock(&lv0104cs->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_PROCESSED:
+ ret = lv0104cs_get_lux(lv0104cs, val, val2);
+ if (ret)
+ goto err_mutex;
+ ret = IIO_VAL_INT_PLUS_MICRO;
+ break;
+
+ case IIO_CHAN_INFO_CALIBSCALE:
+ *val = lv0104cs_calibscales[lv0104cs->calibscale].val;
+ *val2 = lv0104cs_calibscales[lv0104cs->calibscale].val2;
+ ret = IIO_VAL_INT_PLUS_MICRO;
+ break;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = lv0104cs_scales[lv0104cs->scale].val;
+ *val2 = lv0104cs_scales[lv0104cs->scale].val2;
+ ret = IIO_VAL_INT_PLUS_MICRO;
+ break;
+
+ case IIO_CHAN_INFO_INT_TIME:
+ *val = lv0104cs_int_times[lv0104cs->int_time].val;
+ *val2 = lv0104cs_int_times[lv0104cs->int_time].val2;
+ ret = IIO_VAL_INT_PLUS_MICRO;
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+
+err_mutex:
+ mutex_unlock(&lv0104cs->lock);
+
+ return ret;
+}
+
+static int lv0104cs_set_calibscale(struct lv0104cs_private *lv0104cs,
+ int val, int val2)
+{
+ int calibscale = val * 1000000 + val2;
+ int floor, ceil, mid;
+ int ret, i, index;
+
+ /* round to nearest quantized calibscale (sensitivity) */
+ for (i = 0; i < ARRAY_SIZE(lv0104cs_calibscales) - 1; i++) {
+ floor = lv0104cs_calibscales[i].val * 1000000
+ + lv0104cs_calibscales[i].val2;
+ ceil = lv0104cs_calibscales[i + 1].val * 1000000
+ + lv0104cs_calibscales[i + 1].val2;
+ mid = (floor + ceil) / 2;
+
+ /* round down */
+ if (calibscale >= floor && calibscale < mid) {
+ index = i;
+ break;
+ }
+
+ /* round up */
+ if (calibscale >= mid && calibscale <= ceil) {
+ index = i + 1;
+ break;
+ }
+ }
+
+ if (i == ARRAY_SIZE(lv0104cs_calibscales) - 1)
+ return -EINVAL;
+
+ mutex_lock(&lv0104cs->lock);
+
+ /* set calibscale (sensitivity) */
+ ret = lv0104cs_write_reg(lv0104cs->client,
+ lv0104cs_calibscales[index].regval);
+ if (ret)
+ goto err_mutex;
+
+ lv0104cs->calibscale = index;
+
+err_mutex:
+ mutex_unlock(&lv0104cs->lock);
+
+ return ret;
+}
+
+static int lv0104cs_set_scale(struct lv0104cs_private *lv0104cs,
+ int val, int val2)
+{
+ int i;
+
+ /* hard matching */
+ for (i = 0; i < ARRAY_SIZE(lv0104cs_scales); i++) {
+ if (val != lv0104cs_scales[i].val)
+ continue;
+
+ if (val2 == lv0104cs_scales[i].val2)
+ break;
+ }
+
+ if (i == ARRAY_SIZE(lv0104cs_scales))
+ return -EINVAL;
+
+ mutex_lock(&lv0104cs->lock);
+ lv0104cs->scale = i;
+ mutex_unlock(&lv0104cs->lock);
+
+ return 0;
+}
+
+static int lv0104cs_set_int_time(struct lv0104cs_private *lv0104cs,
+ int val, int val2)
+{
+ int i;
+
+ /* hard matching */
+ for (i = 0; i < ARRAY_SIZE(lv0104cs_int_times); i++) {
+ if (val != lv0104cs_int_times[i].val)
+ continue;
+
+ if (val2 == lv0104cs_int_times[i].val2)
+ break;
+ }
+
+ if (i == ARRAY_SIZE(lv0104cs_int_times))
+ return -EINVAL;
+
+ mutex_lock(&lv0104cs->lock);
+ lv0104cs->int_time = i;
+ mutex_unlock(&lv0104cs->lock);
+
+ return 0;
+}
+
+static int lv0104cs_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct lv0104cs_private *lv0104cs = iio_priv(indio_dev);
+
+ if (chan->type != IIO_LIGHT)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_CALIBSCALE:
+ return lv0104cs_set_calibscale(lv0104cs, val, val2);
+
+ case IIO_CHAN_INFO_SCALE:
+ return lv0104cs_set_scale(lv0104cs, val, val2);
+
+ case IIO_CHAN_INFO_INT_TIME:
+ return lv0104cs_set_int_time(lv0104cs, val, val2);
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static ssize_t lv0104cs_show_calibscale_avail(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t len = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(lv0104cs_calibscales); i++) {
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06d ",
+ lv0104cs_calibscales[i].val,
+ lv0104cs_calibscales[i].val2);
+ }
+
+ buf[len - 1] = '\n';
+
+ return len;
+}
+
+static ssize_t lv0104cs_show_scale_avail(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t len = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(lv0104cs_scales); i++) {
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06d ",
+ lv0104cs_scales[i].val,
+ lv0104cs_scales[i].val2);
+ }
+
+ buf[len - 1] = '\n';
+
+ return len;
+}
+
+static ssize_t lv0104cs_show_int_time_avail(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t len = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(lv0104cs_int_times); i++) {
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06d ",
+ lv0104cs_int_times[i].val,
+ lv0104cs_int_times[i].val2);
+ }
+
+ buf[len - 1] = '\n';
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(calibscale_available, 0444,
+ lv0104cs_show_calibscale_avail, NULL, 0);
+static IIO_DEVICE_ATTR(scale_available, 0444,
+ lv0104cs_show_scale_avail, NULL, 0);
+static IIO_DEV_ATTR_INT_TIME_AVAIL(lv0104cs_show_int_time_avail);
+
+static struct attribute *lv0104cs_attributes[] = {
+ &iio_dev_attr_calibscale_available.dev_attr.attr,
+ &iio_dev_attr_scale_available.dev_attr.attr,
+ &iio_dev_attr_integration_time_available.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group lv0104cs_attribute_group = {
+ .attrs = lv0104cs_attributes,
+};
+
+static const struct iio_info lv0104cs_info = {
+ .attrs = &lv0104cs_attribute_group,
+ .read_raw = &lv0104cs_read_raw,
+ .write_raw = &lv0104cs_write_raw,
+};
+
+static const struct iio_chan_spec lv0104cs_channels[] = {
+ {
+ .type = IIO_LIGHT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
+ BIT(IIO_CHAN_INFO_CALIBSCALE) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_INT_TIME),
+ },
+};
+
+static int lv0104cs_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct lv0104cs_private *lv0104cs;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*lv0104cs));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ lv0104cs = iio_priv(indio_dev);
+
+ i2c_set_clientdata(client, lv0104cs);
+ lv0104cs->client = client;
+
+ mutex_init(&lv0104cs->lock);
+
+ lv0104cs->calibscale = LV0104CS_CALIBSCALE_UNITY;
+ lv0104cs->scale = LV0104CS_SCALE_1X;
+ lv0104cs->int_time = LV0104CS_INTEG_200MS;
+
+ ret = lv0104cs_write_reg(lv0104cs->client,
+ lv0104cs_calibscales[LV0104CS_CALIBSCALE_UNITY].regval);
+ if (ret)
+ return ret;
+
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->channels = lv0104cs_channels;
+ indio_dev->num_channels = ARRAY_SIZE(lv0104cs_channels);
+ indio_dev->name = client->name;
+ indio_dev->info = &lv0104cs_info;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id lv0104cs_id[] = {
+ { "lv0104cs", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, lv0104cs_id);
+
+static struct i2c_driver lv0104cs_i2c_driver = {
+ .driver = {
+ .name = "lv0104cs",
+ },
+ .id_table = lv0104cs_id,
+ .probe = lv0104cs_probe,
+};
+module_i2c_driver(lv0104cs_i2c_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
+MODULE_DESCRIPTION("LV0104CS Ambient Light Sensor Driver");
+MODULE_LICENSE("GPL");
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