--- /dev/null
+/*
+ * AL3320A - Dyna Image Ambient Light Sensor
+ *
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * 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.
+ *
+ * IIO driver for AL3320A (7-bit I2C slave address 0x1C).
+ *
+ * TODO: interrupt support, thresholds
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define AL3320A_DRV_NAME "al3320a"
+
+#define AL3320A_REG_CONFIG 0x00
+#define AL3320A_REG_STATUS 0x01
+#define AL3320A_REG_INT 0x02
+#define AL3320A_REG_WAIT 0x06
+#define AL3320A_REG_CONFIG_RANGE 0x07
+#define AL3320A_REG_PERSIST 0x08
+#define AL3320A_REG_MEAN_TIME 0x09
+#define AL3320A_REG_ADUMMY 0x0A
+#define AL3320A_REG_DATA_LOW 0x22
+
+#define AL3320A_REG_LOW_THRESH_LOW 0x30
+#define AL3320A_REG_LOW_THRESH_HIGH 0x31
+#define AL3320A_REG_HIGH_THRESH_LOW 0x32
+#define AL3320A_REG_HIGH_THRESH_HIGH 0x33
+
+#define AL3320A_CONFIG_DISABLE 0x00
+#define AL3320A_CONFIG_ENABLE 0x01
+
+#define AL3320A_GAIN_SHIFT 1
+#define AL3320A_GAIN_MASK (BIT(2) | BIT(1))
+
+/* chip params default values */
+#define AL3320A_DEFAULT_MEAN_TIME 4
+#define AL3320A_DEFAULT_WAIT_TIME 0 /* no waiting */
+
+#define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
+
+enum al3320a_range {
+ AL3320A_RANGE_1, /* 33.28 Klx */
+ AL3320A_RANGE_2, /* 8.32 Klx */
+ AL3320A_RANGE_3, /* 2.08 Klx */
+ AL3320A_RANGE_4 /* 0.65 Klx */
+};
+
+static const int al3320a_scales[][2] = {
+ {0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
+};
+
+struct al3320a_data {
+ struct i2c_client *client;
+};
+
+static const struct iio_chan_spec al3320a_channels[] = {
+ {
+ .type = IIO_LIGHT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ }
+};
+
+static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
+
+static struct attribute *al3320a_attributes[] = {
+ &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group al3320a_attribute_group = {
+ .attrs = al3320a_attributes,
+};
+
+static int al3320a_init(struct al3320a_data *data)
+{
+ int ret;
+
+ /* power on */
+ ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
+ AL3320A_CONFIG_ENABLE);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
+ AL3320A_RANGE_3 << AL3320A_GAIN_SHIFT);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
+ AL3320A_DEFAULT_MEAN_TIME);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
+ AL3320A_DEFAULT_WAIT_TIME);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int al3320a_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct al3320a_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ /*
+ * ALS ADC value is stored in two adjacent registers:
+ * - low byte of output is stored at AL3320A_REG_DATA_LOW
+ * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
+ */
+ ret = i2c_smbus_read_word_data(data->client,
+ AL3320A_REG_DATA_LOW);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ ret = i2c_smbus_read_byte_data(data->client,
+ AL3320A_REG_CONFIG_RANGE);
+ if (ret < 0)
+ return ret;
+
+ ret = (ret & AL3320A_GAIN_MASK) >> AL3320A_GAIN_SHIFT;
+ *val = al3320a_scales[ret][0];
+ *val2 = al3320a_scales[ret][1];
+
+ return IIO_VAL_INT_PLUS_MICRO;
+ }
+ return -EINVAL;
+}
+
+static int al3320a_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val,
+ int val2, long mask)
+{
+ struct al3320a_data *data = iio_priv(indio_dev);
+ int i;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
+ if (val == al3320a_scales[i][0] &&
+ val2 == al3320a_scales[i][1])
+ return i2c_smbus_write_byte_data(data->client,
+ AL3320A_REG_CONFIG_RANGE,
+ i << AL3320A_GAIN_SHIFT);
+ }
+ break;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_info al3320a_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = al3320a_read_raw,
+ .write_raw = al3320a_write_raw,
+ .attrs = &al3320a_attribute_group,
+};
+
+static int al3320a_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct al3320a_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);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &al3320a_info;
+ indio_dev->name = AL3320A_DRV_NAME;
+ indio_dev->channels = al3320a_channels;
+ indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ ret = al3320a_init(data);
+ if (ret < 0) {
+ dev_err(&client->dev, "al3320a chip init failed\n");
+ return ret;
+ }
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int al3320a_remove(struct i2c_client *client)
+{
+ return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG,
+ AL3320A_CONFIG_DISABLE);
+}
+
+static const struct i2c_device_id al3320a_id[] = {
+ {"al3320a", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, al3320a_id);
+
+static struct i2c_driver al3320a_driver = {
+ .driver = {
+ .name = AL3320A_DRV_NAME,
+ },
+ .probe = al3320a_probe,
+ .remove = al3320a_remove,
+ .id_table = al3320a_id,
+};
+
+module_i2c_driver(al3320a_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
+MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-rpi.git / commitdiff