Message-Id: <20220325103014.6597-4-shreeya.patel@collabora.com>
Date:   Fri, 25 Mar 2022 16:00:14 +0530
From:   Shreeya Patel <shreeya.patel@...labora.com>
To:     jic23@...nel.org, lars@...afoo.de, robh+dt@...nel.org,
        Zhigang.Shi@...eon.com, krisman@...labora.com
Cc:     linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel@...labora.com,
        alvaro.soliverez@...labora.com,
        Shreeya Patel <shreeya.patel@...labora.com>
Subject: [PATCH 3/3] iio: light: Add support for ltrf216a sensor

From: Zhigang Shi <Zhigang.Shi@...eon.com>

Add initial support for ltrf216a ambient light sensor.

Datasheet :-
https://gitlab.steamos.cloud/shreeya/iio/-/blob/main/LTR-F216A-QT.pdf


Co-developed-by: Shreeya Patel <shreeya.patel@...labora.com>
Signed-off-by: Shreeya Patel <shreeya.patel@...labora.com>
Signed-off-by: Zhigang Shi <Zhigang.Shi@...eon.com>
---
 drivers/iio/light/Kconfig    |  10 ++
 drivers/iio/light/Makefile   |   1 +
 drivers/iio/light/ltrf216a.c | 334 +++++++++++++++++++++++++++++++++++
 3 files changed, 345 insertions(+)
 create mode 100644 drivers/iio/light/ltrf216a.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index a62c7b4b8678..08fa383a8ca7 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -318,6 +318,16 @@ config SENSORS_LM3533
 	  changes. The ALS-control output values can be set per zone for the
 	  three current output channels.
 
+config LTRF216A
+        tristate "Liteon LTRF216A Light Sensor"
+        depends on I2C
+        help
+          If you say Y or M here, you get support for Liteon LTRF216A
+          Ambient Light Sensor.
+
+          If built as a dynamically linked module, it will be called
+          ltrf216a.
+
 config LTR501
 	tristate "LTR-501ALS-01 light sensor"
 	depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index d10912faf964..8fa91b9fe5b6 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
 obj-$(CONFIG_ISL29125)		+= isl29125.o
 obj-$(CONFIG_JSA1212)		+= jsa1212.o
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
+obj-$(CONFIG_LTRF216A)		+= ltrf216a.o
 obj-$(CONFIG_LTR501)		+= ltr501.o
 obj-$(CONFIG_LV0104CS)		+= lv0104cs.o
 obj-$(CONFIG_MAX44000)		+= max44000.o
diff --git a/drivers/iio/light/ltrf216a.c b/drivers/iio/light/ltrf216a.c
new file mode 100644
index 000000000000..99295358a7fe
--- /dev/null
+++ b/drivers/iio/light/ltrf216a.c
@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LTRF216A Ambient Light Sensor
+ *
+ * Copyright (C) 2021 Lite-On Technology Corp (Singapore)
+ * Author: Shi Zhigang <Zhigang.Shi@...eon.com>
+ *
+ * IIO driver for LTRF216A (7-bit I2C slave address 0x53).
+ */
+
+#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>
+#include <linux/pm.h>
+#include <linux/delay.h>
+
+#define LTRF216A_DRV_NAME "ltrf216a"
+
+#define LTRF216A_MAIN_CTRL		0x00
+
+#define LTRF216A_ALS_MEAS_RATE		0x04
+#define LTRF216A_MAIN_STATUS		0x07
+#define LTRF216A_CLEAR_DATA_0		0x0A
+
+#define LTRF216A_ALS_DATA_0		0x0D
+
+static const int int_time_mapping[] = { 400000, 200000, 100000 };
+
+struct ltrf216a_data {
+	struct i2c_client *client;
+	u32			int_time;
+	u8			int_time_fac;
+	u8			als_gain_fac;
+	struct mutex mutex;
+};
+
+/* open air. need to update based on TP transmission rate. */
+#define WIN_FAC	1
+
+static const struct iio_chan_spec ltrf216a_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_PROCESSED) |
+			BIT(IIO_CHAN_INFO_INT_TIME),
+	}
+};
+
+static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.2 0.4");
+
+static struct attribute *ltrf216a_attributes[] = {
+	&iio_const_attr_integration_time_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group ltrf216a_attribute_group = {
+	.attrs = ltrf216a_attributes,
+};
+
+static int ltrf216a_init(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+
+	ret = i2c_smbus_read_byte_data(data->client, LTRF216A_MAIN_CTRL);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Error reading LTRF216A_MAIN_CTRL\n");
+		return ret;
+	}
+
+	/* enable sensor */
+	ret |= 0x02;
+	ret = i2c_smbus_write_byte_data(data->client, LTRF216A_MAIN_CTRL, ret);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Error writing LTRF216A_MAIN_CTRL\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ltrf216a_disable(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+
+	ret = i2c_smbus_write_byte_data(data->client, LTRF216A_MAIN_CTRL, 0);
+	if (ret < 0)
+		dev_err(&data->client->dev, "Error writing LTRF216A_MAIN_CTRL\n");
+
+	return ret;
+}
+
+static int ltrf216a_set_it_time(struct ltrf216a_data *data, int itime)
+{
+	int i, ret, index = -1;
+	u8 reg;
+
+	for (i = 0; i < ARRAY_SIZE(int_time_mapping); i++) {
+		if (int_time_mapping[i] == itime) {
+			index = i;
+			break;
+		}
+	}
+	/* Make sure integration time index is valid */
+	if (index < 0)
+		return -EINVAL;
+
+	if (index == 0) {
+		reg = 0x03;
+		data->int_time_fac = 4;
+	} else if (index == 1) {
+		reg = 0x13;
+		data->int_time_fac = 2;
+	} else {
+		reg = (index << 4) | 0x02;
+		data->int_time_fac = 1;
+	}
+
+	ret = i2c_smbus_write_byte_data(data->client, LTRF216A_ALS_MEAS_RATE, reg);
+	if (ret < 0)
+		return ret;
+
+	data->int_time = itime;
+
+	return 0;
+}
+
+static int ltrf216a_get_it_time(struct ltrf216a_data *data, int *val, int *val2)
+{
+	*val = 0;
+	*val2 = data->int_time;
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ltrf216a_read_data(struct ltrf216a_data *data, u8 addr)
+{
+	int ret;
+	int tries = 25;
+	int val_0, val_1, val_2;
+
+	while (tries--) {
+		ret = i2c_smbus_read_byte_data(data->client, LTRF216A_MAIN_STATUS);
+		if (ret < 0)
+			return ret;
+		if (ret & 0x08)
+			break;
+		msleep(20);
+	}
+
+	val_0 = i2c_smbus_read_byte_data(data->client, addr);
+	val_1 = i2c_smbus_read_byte_data(data->client, addr + 1);
+	val_2 = i2c_smbus_read_byte_data(data->client, addr + 2);
+	ret = (val_2 << 16) + (val_1 << 8) + val_0;
+
+	return ret;
+}
+
+static int ltrf216a_get_lux(struct ltrf216a_data *data)
+{
+	int greendata, cleardata, lux;
+
+	greendata = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
+	cleardata = ltrf216a_read_data(data, LTRF216A_CLEAR_DATA_0);
+
+	if (greendata < 0 || cleardata < 0)
+		lux = 0;
+	else
+		lux = greendata * 8 * WIN_FAC / data->als_gain_fac / data->int_time_fac / 10;
+
+	return lux;
+}
+
+static int ltrf216a_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int *val,
+			     int *val2, long mask)
+{
+	int ret;
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+
+	mutex_lock(&data->mutex);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		ret = ltrf216a_get_lux(data);
+		*val = ret;
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_INT_TIME:
+		ret = ltrf216a_get_it_time(data, val, val2);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int ltrf216a_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan, int val,
+			      int val2, long mask)
+{
+	struct ltrf216a_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		if (val != 0)
+			return -EINVAL;
+		mutex_lock(&data->mutex);
+		ret = ltrf216a_set_it_time(data, val2);
+		mutex_unlock(&data->mutex);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ltrf216a_info = {
+	.read_raw	= ltrf216a_read_raw,
+	.write_raw	= ltrf216a_write_raw,
+	.attrs		= &ltrf216a_attribute_group,
+};
+
+static int ltrf216a_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct ltrf216a_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;
+
+	mutex_init(&data->mutex);
+
+	indio_dev->info = &ltrf216a_info;
+	indio_dev->name = LTRF216A_DRV_NAME;
+	indio_dev->channels = ltrf216a_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ltrf216a_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = ltrf216a_init(indio_dev);
+	if (ret < 0) {
+		dev_err(&client->dev, "ltrf216a chip init failed\n");
+		return ret;
+	}
+	data->int_time = 100000;
+	data->int_time_fac = 1;
+	data->als_gain_fac = 3;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to register iio dev\n");
+		goto err_init;
+	}
+
+	return 0;
+err_init:
+	ltrf216a_disable(indio_dev);
+	return ret;
+}
+
+static int ltrf216a_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+	ltrf216a_disable(indio_dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int ltrf216a_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+
+	return ltrf216a_disable(indio_dev);
+}
+
+static int ltrf216a_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+
+	return ltrf216a_init(indio_dev);
+}
+
+static SIMPLE_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_suspend, ltrf216a_resume);
+#define LTRF216A_PM_OPS (&ltrf216a_pm_ops)
+#else
+#define LTRF216A_PM_OPS NULL
+#endif
+
+static const struct i2c_device_id ltrf216a_id[] = {
+	{ LTRF216A_DRV_NAME, 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
+
+static const struct of_device_id ltrf216a_of_match[] = {
+	{ .compatible = "ltr,ltrf216a", },
+	{ .compatible = "liteon,ltrf216a", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ltrf216a_of_match);
+
+static struct i2c_driver ltrf216a_driver = {
+	.driver = {
+		.name = LTRF216A_DRV_NAME,
+		.pm = LTRF216A_PM_OPS,
+		.of_match_table = ltrf216a_of_match,
+	},
+	.probe		= ltrf216a_probe,
+	.remove		= ltrf216a_remove,
+	.id_table	= ltrf216a_id,
+};
+
+module_i2c_driver(ltrf216a_driver);
+
+MODULE_AUTHOR("Shi Zhigang <Zhigang.Shi@...eon.com>");
+MODULE_DESCRIPTION("LTRF216A ambient light sensor driver");
+MODULE_LICENSE("GPL v2");
-- 
2.30.2

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