[PATCH v3] iio: Add Dyna-Image AL3320A ambient light sensor driver

From: Daniel Baluta
Date: Fri Aug 22 2014 - 05:13:18 EST

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Minimal implementation. This driver provides raw illuminance readings.

This is based on drivers/hwmon/al3320.c (*) driver from msm tree written
by Tsechih Lin <Tsechih_Lin@xxxxxxxx>

* https://android.googlesource.com/kernel/msm.git

Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
---
Changes since v2: (reported by Peter Meerwald)
* removed definition of DATA_HIGH and SW_RESET as they are not used
* added a comment to al3320a_get_adc_value() function
* added thresholds on TODO list
* small stye fixes

Changes since v1: (reported by Peter Meerwald)
* used u8 instead of int for passing gain and mean_time
* used i2c_smbus_read_word_swapped instead of 2 x i2c_smbus_read_byte_data
* used devm_iio_device_register instead of iio_device_register
* small style fixes

drivers/iio/light/Kconfig | 10 ++
drivers/iio/light/Makefile | 1 +
drivers/iio/light/al3320a.c | 255 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 266 insertions(+)
create mode 100644 drivers/iio/light/al3320a.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index bf05ca5..5bea821 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -17,6 +17,16 @@ config ADJD_S311
This driver can also be built as a module. If so, the module
will be called adjd_s311.

+config AL3320A
+ tristate "AL3320A ambient light sensor"
+ depends on I2C
+ help
+ Say Y here if you want to build a driver for the Dyna Image AL3320A
+ ambient light sensor.
+
+ To compile this driver as a module, choose M here: the
+ module will be called al3320a.
+
config APDS9300
tristate "APDS9300 ambient light sensor"
depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 8b8c09f..47877a3 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -4,6 +4,7 @@

# When adding new entries keep the list in alphabetical order
obj-$(CONFIG_ADJD_S311) += adjd_s311.o
+obj-$(CONFIG_AL3320A) += al3320a.o
obj-$(CONFIG_APDS9300) += apds9300.o
obj-$(CONFIG_CM32181) += cm32181.o
obj-$(CONFIG_CM36651) += cm36651.o
diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c
new file mode 100644
index 0000000..28fc8b0
--- /dev/null
+++ b/drivers/iio/light/al3320a.c
@@ -0,0 +1,255 @@
+/*
+ * 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 BIT(0)
+
+#define AL3320A_GAIN_SHIFT 1
+
+/* chip params default values */
+#define AL3320A_DEFAULT_MEAN_TIME 4
+#define AL3320A_DEFAULT_WAIT_TIME 0 /* no waiting */
+
+enum al3320a_range {
+ AL3320A_RANGE_1, /* 33.28K lux */
+ AL3320A_RANGE_2, /* 8.32K lux */
+ AL3320A_RANGE_3, /* 2.08K lux */
+ AL3320A_RANGE_4 /* 0.65K lux */
+};
+
+static const int al3320a_scales[][2] = {
+ {0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
+};
+
+struct al3320a_data {
+ struct i2c_client *client;
+ u8 range;
+};
+
+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 int al3320a_enable(struct al3320a_data *data)
+{
+ return i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
+ AL3320A_CONFIG_ENABLE);
+}
+
+static int al3320a_disable(struct al3320a_data *data)
+{
+ return i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
+ AL3320A_CONFIG_DISABLE);
+}
+
+static int al3320a_set_config_range(struct al3320a_data *data, u8 gain)
+{
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
+ gain << AL3320A_GAIN_SHIFT);
+ if (ret >= 0)
+ data->range = gain;
+ return ret;
+}
+
+static int al3320a_set_mean_time(struct al3320a_data *data, u8 mean_time)
+{
+ return i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
+ mean_time);
+}
+
+static int al3320a_set_wait_time(struct al3320a_data *data, u8 wait_time)
+{
+ return i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
+ wait_time);
+}
+
+/**
+ * al3320a_get_adc_value() - report raw ADC reading
+ * @data - pointer to struct al3320a_data
+ *
+ * ALS ADC value is stored in two adjacent registers:
+ * - low byte of the channel output is stored at AL3320A_REG_DATA_LOW
+ * - high byte of channel output is stored at AL3320A_REG_DATA_LOW + 1.
+ *
+ * Return: positive raw ADC reading or negative error code.
+ */
+static int al3320a_get_adc_value(struct al3320a_data *data)
+{
+ return i2c_smbus_read_word_swapped(data->client, AL3320A_REG_DATA_LOW);
+}
+
+static int al3320a_init(struct al3320a_data *data)
+{
+ int ret;
+
+ /* power on */
+ ret = al3320a_enable(data);
+ if (ret)
+ return ret;
+
+ ret = al3320a_set_config_range(data, AL3320A_RANGE_3);
+ if (ret)
+ return ret;
+
+ ret = al3320a_set_mean_time(data, AL3320A_DEFAULT_MEAN_TIME);
+ if (ret)
+ return ret;
+
+ ret = al3320a_set_wait_time(data, AL3320A_DEFAULT_WAIT_TIME);
+ if (ret)
+ 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:
+ ret = al3320a_get_adc_value(data);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = al3320a_scales[data->range][0];
+ *val2 = al3320a_scales[data->range][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 al3320a_set_config_range(data, i);
+ }
+ break;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_info al3320a_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = al3320a_read_raw,
+ .write_raw = al3320a_write_raw,
+};
+
+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) {
+ 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)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct al3320a_data *data = iio_priv(indio_dev);
+
+ return al3320a_disable(data);
+}
+
+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@xxxxxxxxx>");
+MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1

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Next message: Stefan Bader: "Re: [Xen-devel] Xen PV domain regression with KASLR enabled (kernel 3.16)"
Previous message: Kay Sievers: "Re: [PATCH v3 03/11] drivers: base: add new class "cpu" to group cpu devices"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]