iio: light: add Dyna-Image AL3010 driver

Based on:
- 3320A in-kernel driver
- https://www.spinics.net/lists/linux-iio/msg25145.html
- https://lore.kernel.org/patchwork/patch/684179/

I decided to keep it aside of AL3320A due to different approach and much
simpler design of 3010.

Tested on Nexus 7 2012 (grouper/tilapia).
Tested-by: David Heidelberg <david@ixit.cz>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/light/Kconfig

@@ -43,6 +43,16 @@ config ADUX1020
 	 To compile this driver as a module, choose M here: the
 	 module will be called adux1020.
 
+config AL3010
+	tristate "AL3010 ambient light sensor"
+	depends on I2C
+	help
+	  Say Y here if you want to build a driver for the Dyna Image AL3010
+	  ambient light sensor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called al3010.
+
 config AL3320A
 	tristate "AL3320A ambient light sensor"
 	depends on I2C

drivers/iio/light/Makefile

@@ -7,6 +7,7 @@
 obj-$(CONFIG_ACPI_ALS)		+= acpi-als.o
 obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
 obj-$(CONFIG_ADUX1020)		+= adux1020.o
+obj-$(CONFIG_AL3010)		+= al3010.o
 obj-$(CONFIG_AL3320A)		+= al3320a.o
 obj-$(CONFIG_APDS9300)		+= apds9300.o
 obj-$(CONFIG_APDS9960)		+= apds9960.o

drivers/iio/light/al3010.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AL3010 - Dyna Image Ambient Light Sensor
+ *
+ * Copyright (c) 2014, Intel Corporation.
+ * Copyright (c) 2016, Dyna-Image Corp.
+ * Copyright (c) 2020, David Heidelberg, Michał Mirosław, Dmitry Osipenko
+ *
+ * IIO driver for AL3010 (7-bit I2C slave address 0x1C).
+ *
+ * TODO: interrupt support, thresholds
+ * When the driver will get support for interrupt handling, then interrupt
+ * will need to be disabled before turning sensor OFF in order to avoid
+ * potential races with the interrupt handling.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define AL3010_DRV_NAME "al3010"
+
+#define AL3010_REG_SYSTEM		0x00
+#define AL3010_REG_DATA_LOW		0x0c
+#define AL3010_REG_CONFIG		0x10
+
+#define AL3010_CONFIG_DISABLE		0x00
+#define AL3010_CONFIG_ENABLE		0x01
+
+#define AL3010_GAIN_MASK		GENMASK(6,4)
+
+#define AL3010_SCALE_AVAILABLE "1.1872 0.2968 0.0742 0.018"
+
+enum al3xxxx_range {
+	AL3XXX_RANGE_1, /* 77806 lx */
+	AL3XXX_RANGE_2, /* 19542 lx */
+	AL3XXX_RANGE_3, /*  4863 lx */
+	AL3XXX_RANGE_4  /*  1216 lx */
+};
+
+static const int al3010_scales[][2] = {
+	{0, 1187200}, {0, 296800}, {0, 74200}, {0, 18600}
+};
+
+struct al3010_data {
+	struct i2c_client *client;
+};
+
+static const struct iio_chan_spec al3010_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, AL3010_SCALE_AVAILABLE);
+
+static struct attribute *al3010_attributes[] = {
+	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group al3010_attribute_group = {
+	.attrs = al3010_attributes,
+};
+
+static int al3010_set_pwr(struct i2c_client *client, bool pwr)
+{
+	u8 val = pwr ? AL3010_CONFIG_ENABLE : AL3010_CONFIG_DISABLE;
+	return i2c_smbus_write_byte_data(client, AL3010_REG_SYSTEM, val);
+}
+
+static void al3010_set_pwr_off(void *_data)
+{
+	struct al3010_data *data = _data;
+
+	al3010_set_pwr(data->client, false);
+}
+
+static int al3010_init(struct al3010_data *data)
+{
+	int ret;
+
+	ret = al3010_set_pwr(data->client, true);
+
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, AL3010_REG_CONFIG,
+					FIELD_PREP(AL3010_GAIN_MASK,
+						   AL3XXX_RANGE_3));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int al3010_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan, int *val,
+			   int *val2, long mask)
+{
+	struct al3010_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 AL3010_REG_DATA_LOW
+		 * - high byte of output is stored at AL3010_REG_DATA_LOW + 1
+		 */
+		ret = i2c_smbus_read_word_data(data->client,
+					       AL3010_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,
+					       AL3010_REG_CONFIG);
+		if (ret < 0)
+			return ret;
+
+		ret = FIELD_GET(AL3010_GAIN_MASK, ret);
+		*val = al3010_scales[ret][0];
+		*val2 = al3010_scales[ret][1];
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+	return -EINVAL;
+}
+
+static int al3010_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int val,
+			    int val2, long mask)
+{
+	struct al3010_data *data = iio_priv(indio_dev);
+	int i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		for (i = 0; i < ARRAY_SIZE(al3010_scales); i++) {
+			if (val != al3010_scales[i][0] ||
+			    val2 != al3010_scales[i][1])
+				continue;
+
+			return i2c_smbus_write_byte_data(data->client,
+					AL3010_REG_CONFIG,
+					FIELD_PREP(AL3010_GAIN_MASK, i));
+		}
+		break;
+	}
+	return -EINVAL;
+}
+
+static const struct iio_info al3010_info = {
+	.read_raw	= al3010_read_raw,
+	.write_raw	= al3010_write_raw,
+	.attrs		= &al3010_attribute_group,
+};
+
+static int al3010_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct al3010_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 = &al3010_info;
+	indio_dev->name = AL3010_DRV_NAME;
+	indio_dev->channels = al3010_channels;
+	indio_dev->num_channels = ARRAY_SIZE(al3010_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = al3010_init(data);
+	if (ret < 0) {
+		dev_err(&client->dev, "al3010 chip init failed\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(&client->dev,
+					al3010_set_pwr_off,
+					data);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int __maybe_unused al3010_suspend(struct device *dev)
+{
+	return al3010_set_pwr(to_i2c_client(dev), false);
+}
+
+static int __maybe_unused al3010_resume(struct device *dev)
+{
+	return al3010_set_pwr(to_i2c_client(dev), true);
+}
+
+static SIMPLE_DEV_PM_OPS(al3010_pm_ops, al3010_suspend, al3010_resume);
+
+static const struct i2c_device_id al3010_id[] = {
+	{"al3010", },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, al3010_id);
+
+static const struct of_device_id al3010_of_match[] = {
+	{ .compatible = "dynaimage,al3010", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, al3010_of_match);
+
+static struct i2c_driver al3010_driver = {
+	.driver = {
+		.name = AL3010_DRV_NAME,
+		.of_match_table = al3010_of_match,
+		.pm = &al3010_pm_ops,
+	},
+	.probe		= al3010_probe,
+	.id_table	= al3010_id,
+};
+module_i2c_driver(al3010_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
+MODULE_AUTHOR("David Heidelberg <david@ixit.cz>");
+MODULE_DESCRIPTION("AL3010 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL v2");