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

[Daniel Baluta]

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>
---
 drivers/iio/light/Kconfig   |  10 ++
 drivers/iio/light/Makefile  |   1 +
 drivers/iio/light/al3320a.c | 261 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 272 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..06ab557
--- /dev/null
+++ b/drivers/iio/light/al3320a.c
@@ -0,0 +1,261 @@
+/*
+ * 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
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/mutex.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_DATA_HIGH		0x23
+
+#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_CONFIG_SW_RESET		BIT(2)
+
+#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, int gain)
+{
+	data->range = gain;
+
+	return i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
+					 gain << AL3320A_GAIN_SHIFT);
+}
+
+static int al3320a_set_mean_time(struct al3320a_data *data, int 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, int wait_time)
+{
+	return i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
+					 wait_time);
+}
+
+static int al3320a_get_adc_value(struct al3320a_data *data)
+{
+	unsigned int low, high;
+
+	high = i2c_smbus_read_byte_data(data->client, AL3320A_REG_DATA_HIGH);
+	if (high < 0)
+		return high;
+
+	low = i2c_smbus_read_byte_data(data->client, AL3320A_REG_DATA_LOW);
+	if (low < 0)
+		return low;
+	return (high << 8) | 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]) {
+				data->range = i;
+				return al3320a_set_config_range(data, i);
+			}
+		}
+	}
+	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 < 0)
+		return ret;
+
+	return iio_device_register(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);
+	int ret;
+
+	iio_device_unregister(indio_dev);
+
+	ret = al3320a_disable(data);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+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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