iio: light: Add support for Azoteq IQS621/622 ambient light sensors

This patch adds support for the Azoteq IQS621 and IQS622 ambient light
sensors, both of which can report a four-bit representation of ambient
light intensity.

The IQS621 can additionally report illuminace directly in units of lux,
while the IQS622 can report a four-bit representation of infrared light
intensity. Furthermore, the IQS622 can report a unitless measurement of
a target's proximity to the device.

Signed-off-by: Jeff LaBundy <[e-mail]>
Reviewed-by: Jonathan Cameron <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/iio/light/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called gp2ap020a00f.
 
+config IQS621_ALS
+	tristate "Azoteq IQS621/622 ambient light sensors"
+	depends on MFD_IQS62X || COMPILE_TEST
+	help
+	  Say Y here if you want to build support for the Azoteq IQS621
+	  and IQS622 ambient light sensors.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called iqs621-als.
+
 config SENSORS_ISL29018
 	tristate "Intersil 29018 light and proximity sensor"
 	depends on I2C

drivers/iio/light/Makefile

···
 obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
 obj-$(CONFIG_HID_SENSOR_PROX)	+= hid-sensor-prox.o
+obj-$(CONFIG_IQS621_ALS)	+= iqs621-als.o
 obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
 obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
 obj-$(CONFIG_ISL29125)		+= isl29125.o

drivers/iio/light/iqs621-als.c

···
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Azoteq IQS621/622 Ambient Light Sensors
+ *
+ * Copyright (C) 2019 Jeff LaBundy <[e-mail]>
+ */
+
+#include <linux/device.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/mfd/iqs62x.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define IQS621_ALS_FLAGS_LIGHT			BIT(7)
+#define IQS621_ALS_FLAGS_RANGE			GENMASK(3, 0)
+
+#define IQS621_ALS_UI_OUT			0x17
+
+#define IQS621_ALS_THRESH_DARK			0x80
+#define IQS621_ALS_THRESH_LIGHT			0x81
+
+#define IQS622_IR_RANGE				0x15
+#define IQS622_IR_FLAGS				0x16
+#define IQS622_IR_FLAGS_TOUCH			BIT(1)
+#define IQS622_IR_FLAGS_PROX			BIT(0)
+
+#define IQS622_IR_UI_OUT			0x17
+
+#define IQS622_IR_THRESH_PROX			0x91
+#define IQS622_IR_THRESH_TOUCH			0x92
+
+struct iqs621_als_private {
+	struct iqs62x_core *iqs62x;
+	struct notifier_block notifier;
+	struct mutex lock;
+	bool light_en;
+	bool range_en;
+	bool prox_en;
+	u8 als_flags;
+	u8 ir_flags_mask;
+	u8 ir_flags;
+	u8 thresh_light;
+	u8 thresh_dark;
+	u8 thresh_prox;
+};
+
+static int iqs621_als_init(struct iqs621_als_private *iqs621_als)
+{
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	unsigned int event_mask = 0;
+	int ret;
+
+	switch (iqs621_als->ir_flags_mask) {
+	case IQS622_IR_FLAGS_TOUCH:
+		ret = regmap_write(iqs62x->regmap, IQS622_IR_THRESH_TOUCH,
+				   iqs621_als->thresh_prox);
+		break;
+
+	case IQS622_IR_FLAGS_PROX:
+		ret = regmap_write(iqs62x->regmap, IQS622_IR_THRESH_PROX,
+				   iqs621_als->thresh_prox);
+		break;
+
+	default:
+		ret = regmap_write(iqs62x->regmap, IQS621_ALS_THRESH_LIGHT,
+				   iqs621_als->thresh_light);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(iqs62x->regmap, IQS621_ALS_THRESH_DARK,
+				   iqs621_als->thresh_dark);
+	}
+
+	if (ret)
+		return ret;
+
+	if (iqs621_als->light_en || iqs621_als->range_en)
+		event_mask |= iqs62x->dev_desc->als_mask;
+
+	if (iqs621_als->prox_en)
+		event_mask |= iqs62x->dev_desc->ir_mask;
+
+	return regmap_update_bits(iqs62x->regmap, IQS620_GLBL_EVENT_MASK,
+				  event_mask, 0);
+}
+
+static int iqs621_als_notifier(struct notifier_block *notifier,
+			       unsigned long event_flags, void *context)
+{
+	struct iqs62x_event_data *event_data = context;
+	struct iqs621_als_private *iqs621_als;
+	struct iio_dev *indio_dev;
+	bool light_new, light_old;
+	bool prox_new, prox_old;
+	u8 range_new, range_old;
+	s64 timestamp;
+	int ret;
+
+	iqs621_als = container_of(notifier, struct iqs621_als_private,
+				  notifier);
+	indio_dev = iio_priv_to_dev(iqs621_als);
+	timestamp = iio_get_time_ns(indio_dev);
+
+	mutex_lock(&iqs621_als->lock);
+
+	if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
+		ret = iqs621_als_init(iqs621_als);
+		if (ret) {
+			dev_err(indio_dev->dev.parent,
+				"Failed to re-initialize device: %d\n", ret);
+			ret = NOTIFY_BAD;
+		} else {
+			ret = NOTIFY_OK;
+		}
+
+		goto err_mutex;
+	}
+
+	if (!iqs621_als->light_en && !iqs621_als->range_en &&
+	    !iqs621_als->prox_en) {
+		ret = NOTIFY_DONE;
+		goto err_mutex;
+	}
+
+	/* IQS621 only */
+	light_new = event_data->als_flags & IQS621_ALS_FLAGS_LIGHT;
+	light_old = iqs621_als->als_flags & IQS621_ALS_FLAGS_LIGHT;
+
+	if (iqs621_als->light_en && light_new && !light_old)
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_RISING),
+			       timestamp);
+	else if (iqs621_als->light_en && !light_new && light_old)
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_FALLING),
+			       timestamp);
+
+	/* IQS621 and IQS622 */
+	range_new = event_data->als_flags & IQS621_ALS_FLAGS_RANGE;
+	range_old = iqs621_als->als_flags & IQS621_ALS_FLAGS_RANGE;
+
+	if (iqs621_als->range_en && (range_new > range_old))
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
+						    IIO_EV_TYPE_CHANGE,
+						    IIO_EV_DIR_RISING),
+			       timestamp);
+	else if (iqs621_als->range_en && (range_new < range_old))
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
+						    IIO_EV_TYPE_CHANGE,
+						    IIO_EV_DIR_FALLING),
+			       timestamp);
+
+	/* IQS622 only */
+	prox_new = event_data->ir_flags & iqs621_als->ir_flags_mask;
+	prox_old = iqs621_als->ir_flags & iqs621_als->ir_flags_mask;
+
+	if (iqs621_als->prox_en && prox_new && !prox_old)
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_RISING),
+			       timestamp);
+	else if (iqs621_als->prox_en && !prox_new && prox_old)
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_FALLING),
+			       timestamp);
+
+	iqs621_als->als_flags = event_data->als_flags;
+	iqs621_als->ir_flags = event_data->ir_flags;
+	ret = NOTIFY_OK;
+
+err_mutex:
+	mutex_unlock(&iqs621_als->lock);
+
+	return ret;
+}
+
+static void iqs621_als_notifier_unregister(void *context)
+{
+	struct iqs621_als_private *iqs621_als = context;
+	struct iio_dev *indio_dev = iio_priv_to_dev(iqs621_als);
+	int ret;
+
+	ret = blocking_notifier_chain_unregister(&iqs621_als->iqs62x->nh,
+						 &iqs621_als->notifier);
+	if (ret)
+		dev_err(indio_dev->dev.parent,
+			"Failed to unregister notifier: %d\n", ret);
+}
+
+static int iqs621_als_read_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int *val, int *val2, long mask)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	int ret;
+	__le16 val_buf;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		ret = regmap_read(iqs62x->regmap, chan->address, val);
+		if (ret)
+			return ret;
+
+		*val &= IQS621_ALS_FLAGS_RANGE;
+		return IIO_VAL_INT;
+
+	case IIO_PROXIMITY:
+	case IIO_LIGHT:
+		ret = regmap_raw_read(iqs62x->regmap, chan->address, &val_buf,
+				      sizeof(val_buf));
+		if (ret)
+			return ret;
+
+		*val = le16_to_cpu(val_buf);
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int iqs621_als_read_event_config(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					enum iio_event_type type,
+					enum iio_event_direction dir)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&iqs621_als->lock);
+
+	switch (chan->type) {
+	case IIO_LIGHT:
+		ret = iqs621_als->light_en;
+		break;
+
+	case IIO_INTENSITY:
+		ret = iqs621_als->range_en;
+		break;
+
+	case IIO_PROXIMITY:
+		ret = iqs621_als->prox_en;
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&iqs621_als->lock);
+
+	return ret;
+}
+
+static int iqs621_als_write_event_config(struct iio_dev *indio_dev,
+					 const struct iio_chan_spec *chan,
+					 enum iio_event_type type,
+					 enum iio_event_direction dir,
+					 int state)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	unsigned int val;
+	int ret;
+
+	mutex_lock(&iqs621_als->lock);
+
+	ret = regmap_read(iqs62x->regmap, iqs62x->dev_desc->als_flags, &val);
+	if (ret)
+		goto err_mutex;
+	iqs621_als->als_flags = val;
+
+	switch (chan->type) {
+	case IIO_LIGHT:
+		ret = regmap_update_bits(iqs62x->regmap, IQS620_GLBL_EVENT_MASK,
+					 iqs62x->dev_desc->als_mask,
+					 iqs621_als->range_en || state ? 0 :
+									 0xFF);
+		if (!ret)
+			iqs621_als->light_en = state;
+		break;
+
+	case IIO_INTENSITY:
+		ret = regmap_update_bits(iqs62x->regmap, IQS620_GLBL_EVENT_MASK,
+					 iqs62x->dev_desc->als_mask,
+					 iqs621_als->light_en || state ? 0 :
+									 0xFF);
+		if (!ret)
+			iqs621_als->range_en = state;
+		break;
+
+	case IIO_PROXIMITY:
+		ret = regmap_read(iqs62x->regmap, IQS622_IR_FLAGS, &val);
+		if (ret)
+			goto err_mutex;
+		iqs621_als->ir_flags = val;
+
+		ret = regmap_update_bits(iqs62x->regmap, IQS620_GLBL_EVENT_MASK,
+					 iqs62x->dev_desc->ir_mask,
+					 state ? 0 : 0xFF);
+		if (!ret)
+			iqs621_als->prox_en = state;
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+
+err_mutex:
+	mutex_unlock(&iqs621_als->lock);
+
+	return ret;
+}
+
+static int iqs621_als_read_event_value(struct iio_dev *indio_dev,
+				       const struct iio_chan_spec *chan,
+				       enum iio_event_type type,
+				       enum iio_event_direction dir,
+				       enum iio_event_info info,
+				       int *val, int *val2)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	int ret = IIO_VAL_INT;
+
+	mutex_lock(&iqs621_als->lock);
+
+	switch (dir) {
+	case IIO_EV_DIR_RISING:
+		*val = iqs621_als->thresh_light * 16;
+		break;
+
+	case IIO_EV_DIR_FALLING:
+		*val = iqs621_als->thresh_dark * 4;
+		break;
+
+	case IIO_EV_DIR_EITHER:
+		if (iqs621_als->ir_flags_mask == IQS622_IR_FLAGS_TOUCH)
+			*val = iqs621_als->thresh_prox * 4;
+		else
+			*val = iqs621_als->thresh_prox;
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&iqs621_als->lock);
+
+	return ret;
+}
+
+static int iqs621_als_write_event_value(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					enum iio_event_type type,
+					enum iio_event_direction dir,
+					enum iio_event_info info,
+					int val, int val2)
+{
+	struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+	struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+	unsigned int thresh_reg, thresh_val;
+	u8 ir_flags_mask, *thresh_cache;
+	int ret = -EINVAL;
+
+	mutex_lock(&iqs621_als->lock);
+
+	switch (dir) {
+	case IIO_EV_DIR_RISING:
+		thresh_reg = IQS621_ALS_THRESH_LIGHT;
+		thresh_val = val / 16;
+
+		thresh_cache = &iqs621_als->thresh_light;
+		ir_flags_mask = 0;
+		break;
+
+	case IIO_EV_DIR_FALLING:
+		thresh_reg = IQS621_ALS_THRESH_DARK;
+		thresh_val = val / 4;
+
+		thresh_cache = &iqs621_als->thresh_dark;
+		ir_flags_mask = 0;
+		break;
+
+	case IIO_EV_DIR_EITHER:
+		/*
+		 * The IQS622 supports two detection thresholds, both measured
+		 * in the same arbitrary units reported by read_raw: proximity
+		 * (0 through 255 in steps of 1), and touch (0 through 1020 in
+		 * steps of 4).
+		 *
+		 * Based on the single detection threshold chosen by the user,
+		 * select the hardware threshold that gives the best trade-off
+		 * between range and resolution.
+		 *
+		 * By default, the close-range (but coarse) touch threshold is
+		 * chosen during probe.
+		 */
+		switch (val) {
+		case 0 ... 255:
+			thresh_reg = IQS622_IR_THRESH_PROX;
+			thresh_val = val;
+
+			ir_flags_mask = IQS622_IR_FLAGS_PROX;
+			break;
+
+		case 256 ... 1020:
+			thresh_reg = IQS622_IR_THRESH_TOUCH;
+			thresh_val = val / 4;
+
+			ir_flags_mask = IQS622_IR_FLAGS_TOUCH;
+			break;
+
+		default:
+			goto err_mutex;
+		}
+
+		thresh_cache = &iqs621_als->thresh_prox;
+		break;
+
+	default:
+		goto err_mutex;
+	}
+
+	if (thresh_val > 0xFF)
+		goto err_mutex;
+
+	ret = regmap_write(iqs62x->regmap, thresh_reg, thresh_val);
+	if (ret)
+		goto err_mutex;
+
+	*thresh_cache = thresh_val;
+	iqs621_als->ir_flags_mask = ir_flags_mask;
+
+err_mutex:
+	mutex_unlock(&iqs621_als->lock);
+
+	return ret;
+}
+
+static const struct iio_info iqs621_als_info = {
+	.read_raw = &iqs621_als_read_raw,
+	.read_event_config = iqs621_als_read_event_config,
+	.write_event_config = iqs621_als_write_event_config,
+	.read_event_value = iqs621_als_read_event_value,
+	.write_event_value = iqs621_als_write_event_value,
+};
+
+static const struct iio_event_spec iqs621_als_range_events[] = {
+	{
+		.type = IIO_EV_TYPE_CHANGE,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	},
+};
+
+static const struct iio_event_spec iqs621_als_light_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	},
+};
+
+static const struct iio_chan_spec iqs621_als_channels[] = {
+	{
+		.type = IIO_INTENSITY,
+		.address = IQS621_ALS_FLAGS,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.event_spec = iqs621_als_range_events,
+		.num_event_specs = ARRAY_SIZE(iqs621_als_range_events),
+	},
+	{
+		.type = IIO_LIGHT,
+		.address = IQS621_ALS_UI_OUT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.event_spec = iqs621_als_light_events,
+		.num_event_specs = ARRAY_SIZE(iqs621_als_light_events),
+	},
+};
+
+static const struct iio_event_spec iqs622_als_prox_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+				 BIT(IIO_EV_INFO_VALUE),
+	},
+};
+
+static const struct iio_chan_spec iqs622_als_channels[] = {
+	{
+		.type = IIO_INTENSITY,
+		.channel2 = IIO_MOD_LIGHT_BOTH,
+		.address = IQS622_ALS_FLAGS,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.event_spec = iqs621_als_range_events,
+		.num_event_specs = ARRAY_SIZE(iqs621_als_range_events),
+		.modified = true,
+	},
+	{
+		.type = IIO_INTENSITY,
+		.channel2 = IIO_MOD_LIGHT_IR,
+		.address = IQS622_IR_RANGE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.modified = true,
+	},
+	{
+		.type = IIO_PROXIMITY,
+		.address = IQS622_IR_UI_OUT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.event_spec = iqs622_als_prox_events,
+		.num_event_specs = ARRAY_SIZE(iqs622_als_prox_events),
+	},
+};
+
+static int iqs621_als_probe(struct platform_device *pdev)
+{
+	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
+	struct iqs621_als_private *iqs621_als;
+	struct iio_dev *indio_dev;
+	unsigned int val;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*iqs621_als));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	iqs621_als = iio_priv(indio_dev);
+	iqs621_als->iqs62x = iqs62x;
+
+	if (iqs62x->dev_desc->prod_num == IQS622_PROD_NUM) {
+		ret = regmap_read(iqs62x->regmap, IQS622_IR_THRESH_TOUCH,
+				  &val);
+		if (ret)
+			return ret;
+		iqs621_als->thresh_prox = val;
+		iqs621_als->ir_flags_mask = IQS622_IR_FLAGS_TOUCH;
+
+		indio_dev->channels = iqs622_als_channels;
+		indio_dev->num_channels = ARRAY_SIZE(iqs622_als_channels);
+	} else {
+		ret = regmap_read(iqs62x->regmap, IQS621_ALS_THRESH_LIGHT,
+				  &val);
+		if (ret)
+			return ret;
+		iqs621_als->thresh_light = val;
+
+		ret = regmap_read(iqs62x->regmap, IQS621_ALS_THRESH_DARK,
+				  &val);
+		if (ret)
+			return ret;
+		iqs621_als->thresh_dark = val;
+
+		indio_dev->channels = iqs621_als_channels;
+		indio_dev->num_channels = ARRAY_SIZE(iqs621_als_channels);
+	}
+
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->name = iqs62x->dev_desc->dev_name;
+	indio_dev->info = &iqs621_als_info;
+
+	mutex_init(&iqs621_als->lock);
+
+	iqs621_als->notifier.notifier_call = iqs621_als_notifier;
+	ret = blocking_notifier_chain_register(&iqs621_als->iqs62x->nh,
+					       &iqs621_als->notifier);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(&pdev->dev,
+				       iqs621_als_notifier_unregister,
+				       iqs621_als);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static struct platform_driver iqs621_als_platform_driver = {
+	.driver = {
+		.name = "iqs621-als",
+	},
+	.probe = iqs621_als_probe,
+};
+module_platform_driver(iqs621_als_platform_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <[e-mail]>");
+MODULE_DESCRIPTION("Azoteq IQS621/622 Ambient Light Sensors");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:iqs621-als");