[PATCH 0/3] iio: add Intersil isl76683 light sensor support

[PATCH 0/3] iio: add Intersil isl76683 light sensor support

[Christoph Fritz]

This patchset adds initial support for isl76683 light sensor.

Christoph Fritz (3):
  iio: light: add support for Intersil isl76683 sensor
  dt-bindings: iio: add Intersil isl76683 light sensor bindings
  iio: light: isl76683 add way to adjust irq threshold

 .../ABI/testing/sysfs-bus-iio-light-isl76683       |  17 +
 .../devicetree/bindings/iio/light/isl76683.txt     |  26 +
 drivers/iio/light/Kconfig                          |  12 +
 drivers/iio/light/Makefile                         |   1 +
 drivers/iio/light/isl76683.c                       | 743 +++++++++++++++++++++
 5 files changed, 799 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-light-isl76683
 create mode 100644 Documentation/devicetree/bindings/iio/light/isl76683.txt
 create mode 100644 drivers/iio/light/isl76683.c

-- 
2.1.4

[PATCH 1/3] iio: light: add support for Intersil isl76683 sensor

[Christoph Fritz]

This patch adds support for Intersil isl76683 light sensor.

Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
---
 drivers/iio/light/Kconfig    |  12 +
 drivers/iio/light/Makefile   |   1 +
 drivers/iio/light/isl76683.c | 693 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 706 insertions(+)
 create mode 100644 drivers/iio/light/isl76683.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 2356ed9..4f0882c 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -194,6 +194,18 @@ config ISL29125
 	  To compile this driver as a module, choose M here: the module will be
 	  called isl29125.
 
+config ISL76683
+	tristate "Intersil ISL76683 light sensor"
+	depends on I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say Y here if you want to build a driver for the Intersil ISL76683
+	  light sensor for I2C.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called isl76683.
+
 config HID_SENSOR_ALS
 	depends on HID_SENSOR_HUB
 	select IIO_BUFFER
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index fa32fa4..886a51f 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_HID_SENSOR_PROX)	+= hid-sensor-prox.o
 obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
 obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
 obj-$(CONFIG_ISL29125)		+= isl29125.o
+obj-$(CONFIG_ISL76683)		+= isl76683.o
 obj-$(CONFIG_JSA1212)		+= jsa1212.o
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
 obj-$(CONFIG_LTR501)		+= ltr501.o
diff --git a/drivers/iio/light/isl76683.c b/drivers/iio/light/isl76683.c
new file mode 100644
index 0000000..b730276
--- /dev/null
+++ b/drivers/iio/light/isl76683.c
@@ -0,0 +1,693 @@
+/*
+ * IIO driver for the light sensor ISL76683.
+ *
+ * Copyright (c) 2017 Christoph Fritz <chf.fritz@googlemail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * Datasheet:
+ *  http://www.intersil.com/content/dam/Intersil/documents/isl7/isl76683.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/util_macros.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define ISL76683_REG_CMD		0x00
+#define ISL76683_REG_CTRL		0x01
+#define ISL76683_REG_THR_HI		0x02
+#define ISL76683_REG_THR_LO		0x03
+#define ISL76683_REG_SENSOR_L		0x04
+#define ISL76683_REG_SENSOR_M		0x05
+#define ISL76683_REG_CLEAR_INT		0x40
+#define ISL76683_REGMAP_MAX		0x40
+
+#define ISL76683_CMD_ENABLE		BIT(7)
+#define ISL76683_CMD_PWRDWN		BIT(6)
+#define ISL76683_WIDTH_MASK		0x3
+#define ISL76683_PHOTOD_SHFT		2
+#define ISL76683_PHOTOD_MASK		(0x3 << ISL76683_PHOTOD_SHFT)
+#define ISL76683_INTPERS_MASK		0x3
+#define ISL76683_LUXRANGE_SHFT		2
+#define ISL76683_LUXRANGE_MASK		(0x3 << ISL76683_LUXRANGE_SHFT)
+#define ISL76683_LUXRANGE_STR		"1000 4000 16000 64000"
+
+enum isl76683_dmode {
+	ISL76683_DIODE_0 = 0,
+	ISL76683_DIODE_IR,
+	ISL76683_DIODE_DIFF,
+};
+
+enum isl76683_lux_range {
+	ISL76683_LUX_1000 = 0,
+	ISL76683_LUX_4000,
+	ISL76683_LUX_16000,
+	ISL76683_LUX_64000,
+};
+
+static const int isl76683_lux_ranges_available[] = {
+	1000, 4000, 16000, 64000};
+
+#define ISL76683_LUX_RANGE_DEFAULT	ISL76683_LUX_1000
+#define ISL76683_DIODE_MAX		ISL76683_DIODE_DIFF
+#define ISL76683_DIODE_DEFAULT		ISL76683_DIODE_0
+#define ISL76683_WIDTH_DEFAULT		0x0
+#define ISL76683_RESOLUTION_DEFAULT	16
+#define ISL76683_EXT_RESISTOR_DEFAULT	100
+#define ISL76683_KOHM_MIN		1
+#define ISL76683_KOHM_MAX		1000
+#define ISL76683_INTPERS_DEFAULT	0x0
+#define ISL76683_THR_DEFAULT		0x7f
+
+struct isl76683_chip {
+	enum isl76683_lux_range	luxrange;
+	int			external_resistor;
+	enum isl76683_dmode	photodiode;
+	struct i2c_client	*client;
+	struct regmap		*rmp;
+	struct completion	irq_complete;
+	struct iio_trigger	*trig;
+	bool			trig_enabled;
+	struct mutex		lock;
+	__le16			*buffer;
+	s64			time_ns;
+	bool			buffer_running;
+};
+
+static bool isl76683_readable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case ISL76683_REG_CMD:
+	case ISL76683_REG_CTRL:
+	case ISL76683_REG_THR_HI:
+	case ISL76683_REG_THR_LO:
+	case ISL76683_REG_SENSOR_L:
+	case ISL76683_REG_SENSOR_M:
+	case ISL76683_REG_CLEAR_INT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool isl76683_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case ISL76683_REG_CMD:
+	case ISL76683_REG_CTRL:
+	case ISL76683_REG_THR_HI:
+	case ISL76683_REG_THR_LO:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool isl76683_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case ISL76683_REG_SENSOR_L:
+	case ISL76683_REG_SENSOR_M:
+	case ISL76683_REG_CLEAR_INT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config isl76683_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = ISL76683_REGMAP_MAX,
+	.readable_reg = isl76683_readable_reg,
+	.writeable_reg = isl76683_writeable_reg,
+	.volatile_reg = isl76683_is_volatile_reg,
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int isl76683_set_config(struct isl76683_chip *chip)
+{
+	int ret;
+
+	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CTRL,
+				ISL76683_LUXRANGE_MASK | ISL76683_INTPERS_MASK,
+				(chip->luxrange << ISL76683_LUXRANGE_SHFT) |
+				ISL76683_INTPERS_DEFAULT);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
+				ISL76683_PHOTOD_MASK | ISL76683_WIDTH_MASK,
+				(chip->photodiode << ISL76683_PHOTOD_SHFT) |
+				ISL76683_WIDTH_DEFAULT);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(chip->rmp, ISL76683_REG_THR_HI,
+				ISL76683_THR_DEFAULT);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(chip->rmp, ISL76683_REG_THR_LO,
+				ISL76683_THR_DEFAULT);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int isl76683_power(struct isl76683_chip *chip, bool on)
+{
+	int ret;
+
+	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
+				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
+				0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
+				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
+				on ? ISL76683_CMD_ENABLE : ISL76683_CMD_PWRDWN);
+	if (ret < 0)
+		return ret;
+
+	return on ? isl76683_set_config(chip) : 0;
+}
+
+static int isl76683_reset(struct isl76683_chip *chip)
+{
+	int ret;
+
+	ret = isl76683_power(chip, false);
+	if (ret < 0)
+		return ret;
+
+	return isl76683_power(chip, true);
+}
+
+static int isl76683_read_lux(struct isl76683_chip *chip,
+			     bool is_processed, int *val)
+{
+	unsigned int sensor_data, range, fsr;
+	__le16 sensor_raw;
+	int ret;
+
+	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L,
+				&sensor_raw, sizeof(sensor_raw));
+	if (ret)
+		return ret;
+
+	sensor_data = le16_to_cpu(sensor_raw);
+
+	if (!is_processed) {
+		*val = sensor_data;
+		return 0;
+	}
+
+	/* range values taken from datasheet (table 9) */
+	if (chip->luxrange == ISL76683_LUX_1000)
+		range = 973;
+	else if (chip->luxrange == ISL76683_LUX_4000)
+		range = 3892;
+	else if (chip->luxrange == ISL76683_LUX_16000)
+		range = 15568;
+	else if (chip->luxrange == ISL76683_LUX_64000)
+		range = 62272;
+	else
+		return -EINVAL;
+
+	/* equations from datasheet (EQ.3 and EQ.4) */
+	fsr = (100 * range) / chip->external_resistor;
+	*val = (fsr * sensor_data) / (1 << ISL76683_RESOLUTION_DEFAULT);
+
+	return 0;
+}
+
+static irqreturn_t isl76683_interrupt_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+
+	chip->time_ns = iio_get_time_ns(indio_dev);
+
+	if (chip->trig_enabled)
+		iio_trigger_poll(chip->trig);
+
+	if (!completion_done(&chip->irq_complete))
+		complete(&chip->irq_complete);
+
+	return IRQ_HANDLED;
+}
+
+static inline int isl76683_start_measurement(struct isl76683_chip *chip)
+{
+	int dummy;
+
+	/* dummy read is clearing irq and triggers new measurement */
+	return regmap_read(chip->rmp, ISL76683_REG_CLEAR_INT, &dummy);
+}
+
+static int isl76683_singleshot_conversion(struct isl76683_chip *chip,
+					  const struct iio_chan_spec *chan,
+					  bool is_processed, int *val)
+{
+	long timeout;
+	int ret;
+
+	if (chip->buffer_running)
+		return -EAGAIN;
+
+	switch (chan->channel2) {
+	case IIO_MOD_LIGHT_BOTH:
+		chip->photodiode = ISL76683_DIODE_DIFF;
+		break;
+	case IIO_MOD_LIGHT_IR:
+		chip->photodiode = ISL76683_DIODE_IR;
+		break;
+	default:
+		chip->photodiode = ISL76683_DIODE_0;
+	}
+
+	ret = isl76683_set_config(chip);
+	if (ret)
+		return ret;
+
+	ret = isl76683_start_measurement(chip);
+	if (ret < 0)
+		return ret;
+
+	/* wait for measurement to complete */
+	timeout = wait_for_completion_interruptible_timeout(
+			&chip->irq_complete,
+			msecs_to_jiffies(5000));
+	if (timeout == 0) {
+		dev_err(&chip->client->dev, "measurement timed out\n");
+		return -ETIMEDOUT;
+	} else if (timeout < 0) {
+		dev_err(&chip->client->dev, "wait for measurement failed\n");
+		return -EINTR;
+	}
+
+	ret = isl76683_read_lux(chip, is_processed, val);
+	if (ret) {
+		dev_err(&chip->client->dev, "%s: Error %d reading lux\n",
+				__func__, ret);
+		return ret;
+	}
+
+	return IIO_VAL_INT;
+}
+
+static irqreturn_t isl76683_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+	__le16 buf;
+	int ret;
+
+	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L, &buf, 2);
+	if (ret)
+		return ret;
+
+	chip->buffer[0] = le16_to_cpu(buf);
+
+	iio_push_to_buffers_with_timestamp(indio_dev, chip->buffer,
+					   chip->time_ns);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	ret = isl76683_start_measurement(chip);
+	if (ret < 0)
+		return ret;
+
+	return IRQ_HANDLED;
+}
+
+static int isl76683_buffer_preenable(struct iio_dev *indio_dev)
+{
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+
+	mutex_lock(&chip->lock);
+	chip->buffer_running = true;
+	mutex_unlock(&chip->lock);
+	chip->photodiode = indio_dev->channels[0].channel2;
+	return isl76683_set_config(chip);
+}
+
+static int isl76683_buffer_postdisable(struct iio_dev *indio_dev)
+{
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+
+	chip->buffer_running = false;
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops isl76683_buffer_setup_ops = {
+	.preenable = &isl76683_buffer_preenable,
+	.postdisable = &isl76683_buffer_postdisable,
+	.predisable = iio_triggered_buffer_predisable,
+	.postenable = iio_triggered_buffer_postenable,
+	.validate_scan_mask = &iio_validate_scan_mask_onehot,
+};
+
+static int isl76683_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val, int *val2, long mask)
+{
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&chip->lock);
+		ret = isl76683_singleshot_conversion(chip, chan, false, val);
+		mutex_unlock(&chip->lock);
+		return ret;
+	case IIO_CHAN_INFO_PROCESSED:
+		mutex_lock(&chip->lock);
+		ret = isl76683_singleshot_conversion(chip, chan, true, val);
+		mutex_unlock(&chip->lock);
+		return ret;
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		*val = isl76683_lux_ranges_available[chip->luxrange];
+		return IIO_VAL_INT;
+	}
+
+	return -EINVAL;
+}
+
+static int isl76683_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		mutex_lock(&chip->lock);
+		chip->luxrange = find_closest(val,
+			isl76683_lux_ranges_available,
+			ARRAY_SIZE(isl76683_lux_ranges_available));
+		ret = isl76683_set_config(chip);
+		mutex_unlock(&chip->lock);
+		return ret;
+	}
+
+	return -EINVAL;
+}
+
+static IIO_CONST_ATTR(in_illuminance_hardwaregain_available,
+		ISL76683_LUXRANGE_STR);
+
+static struct attribute *isl76683_attributes[] = {
+	&iio_const_attr_in_illuminance_hardwaregain_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group isl76683_attribute_group = {
+	.attrs = isl76683_attributes,
+};
+
+#define ISL76683_CHANNEL_2(_ch2, _si) { \
+	.type = IIO_LIGHT, \
+	.modified = 1, \
+	.channel2 = _ch2, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+			BIT(IIO_CHAN_INFO_PROCESSED), \
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
+	.scan_index = _si, \
+	.scan_type = { \
+		.sign = 'u', \
+		.realbits = 16, \
+		.storagebits = 16, \
+		.endianness = IIO_CPU, \
+	}, \
+}
+
+static const struct iio_chan_spec isl76683_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_CPU,
+		},
+	},
+	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_IR, 1),
+	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_BOTH, 2),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static int isl76683_update_scan_mode(struct iio_dev *indio_dev,
+	const unsigned long *scan_mask)
+{
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+
+	kfree(chip->buffer);
+	chip->buffer = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
+	if (chip->buffer == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static const struct iio_info isl76683_info = {
+	.update_scan_mode = isl76683_update_scan_mode,
+	.read_raw = isl76683_read_raw,
+	.write_raw = isl76683_write_raw,
+	.attrs = &isl76683_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static int isl76683_set_trigger_state(struct iio_trigger *trig, bool enable)
+{
+	struct isl76683_chip *chip = iio_trigger_get_drvdata(trig);
+	int ret;
+
+	if (enable) {
+		chip->trig_enabled = true;
+		ret = isl76683_start_measurement(chip);
+		if (ret < 0)
+			return ret;
+	} else
+		chip->trig_enabled = false;
+
+	return 0;
+}
+
+static const struct iio_trigger_ops isl76683_trigger_ops = {
+	.owner = THIS_MODULE,
+	.set_trigger_state = isl76683_set_trigger_state,
+	.validate_device = iio_trigger_validate_own_device,
+};
+
+static int isl76683_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct isl76683_chip *chip;
+	struct iio_dev *indio_dev;
+	struct device_node *np = client->dev.of_node;
+	int rs = ISL76683_EXT_RESISTOR_DEFAULT;
+	int v, ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	chip = iio_priv(indio_dev);
+
+	i2c_set_clientdata(client, indio_dev);
+	chip->client = client;
+
+	if (np) {
+		ret = of_property_read_u32(np, "isil,external-resistor", &v);
+		if (ret || v < ISL76683_KOHM_MIN || v > ISL76683_KOHM_MAX)
+			dev_warn(&client->dev,
+				 "assuming %i kOhm resistor\n", rs);
+		else
+			rs = v;
+	}
+
+	chip->luxrange = ISL76683_LUX_RANGE_DEFAULT;
+	chip->external_resistor = rs;
+	chip->photodiode = ISL76683_DIODE_DEFAULT;
+	chip->buffer_running = false;
+
+	chip->rmp = devm_regmap_init_i2c(client, &isl76683_regmap_config);
+	if (IS_ERR(chip->rmp)) {
+		ret = PTR_ERR(chip->rmp);
+		dev_err(&client->dev, "%s: Error %d initializing regmap\n",
+			__func__, ret);
+		return ret;
+	}
+
+	mutex_init(&chip->lock);
+
+	init_completion(&chip->irq_complete);
+
+	if (!client->irq) {
+		dev_err(&client->dev, "no interrupt configured\n");
+		return -EINVAL;
+	}
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &isl76683_info;
+	indio_dev->channels = isl76683_channels;
+	indio_dev->num_channels = ARRAY_SIZE(isl76683_channels);
+	indio_dev->name = id->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	chip->trig_enabled = false;
+	chip->trig = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
+			indio_dev->name, indio_dev->id);
+	if (!chip->trig)
+		return -ENOMEM;
+
+	chip->trig->ops = &isl76683_trigger_ops;
+	chip->trig->dev.parent = &client->dev;
+	iio_trigger_set_drvdata(chip->trig, chip);
+
+	ret = devm_request_irq(&client->dev, client->irq,
+			isl76683_interrupt_handler,
+			IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+			"isl76683_event", indio_dev);
+	if (ret) {
+		dev_err(&client->dev, "irq request error\n");
+		return ret;
+	}
+
+	ret = devm_iio_trigger_register(&client->dev, chip->trig);
+	if (ret) {
+		dev_err(&client->dev, "iio_trigger register error\n");
+		return ret;
+	}
+
+	ret = isl76683_reset(chip);
+	if (ret) {
+		dev_err(&client->dev, "reset failed\n");
+		return ret;
+	}
+
+	ret = isl76683_read_lux(chip, false, &v);
+	if (ret) {
+		dev_err(&client->dev, "initial dummy readout failed\n");
+		return ret;
+	}
+
+	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
+			&isl76683_trigger_handler, &isl76683_buffer_setup_ops);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_device_register(&client->dev, indio_dev);
+	if (ret) {
+		dev_err(&client->dev,
+			"%s(): iio registration failed with error %d\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int isl76683_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct isl76683_chip *chip = iio_priv(indio_dev);
+
+	pm_runtime_disable(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+	isl76683_power(chip, false);
+	kfree(chip->buffer);
+
+	return 0;
+}
+
+#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM)
+static int isl76683_runtime_suspend(struct device *dev)
+{
+	struct isl76683_chip *chip =
+		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+	int ret;
+
+	mutex_lock(&chip->lock);
+	ret = isl76683_power(chip, false);
+	regcache_mark_dirty(chip->rmp);
+	mutex_unlock(&chip->lock);
+
+	return ret;
+}
+
+static int isl76683_runtime_resume(struct device *dev)
+{
+	struct isl76683_chip *chip =
+		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+	int ret;
+
+	mutex_lock(&chip->lock);
+	ret = isl76683_power(chip, true);
+	mutex_unlock(&chip->lock);
+
+	return ret;
+}
+#endif
+
+static const struct dev_pm_ops isl76683_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(isl76683_runtime_suspend,
+			   isl76683_runtime_resume, NULL)
+};
+
+static const struct i2c_device_id isl76683_id[] = {
+	{"isl76683", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, isl76683_id);
+
+static const struct of_device_id isl76683_of_match[] = {
+	{ .compatible = "isil,isl76683", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, isl76683_of_match);
+
+static struct i2c_driver isl76683_driver = {
+	.driver  = {
+		.name = "isl76683",
+		.of_match_table = isl76683_of_match,
+		.pm = &isl76683_pm_ops,
+	},
+	.probe = isl76683_probe,
+	.remove = isl76683_remove,
+	.id_table = isl76683_id,
+};
+
+module_i2c_driver(isl76683_driver);
+
+MODULE_DESCRIPTION("ISL76683 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christoph Fritz <chf.fritz@googlemail.com>");
-- 
2.1.4

Re: [PATCH 1/3] iio: light: add support for Intersil isl76683 sensor

[Peter Meerwald-Stadler]

On Tue, 7 Nov 2017, Christoph Fritz wrote:

> This patch adds support for Intersil isl76683 light sensor.

nitpicking in subject: maybe 'Add support...', start uppercase 
more comments below
 
> Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
> ---
>  drivers/iio/light/Kconfig    |  12 +
>  drivers/iio/light/Makefile   |   1 +
>  drivers/iio/light/isl76683.c | 693 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 706 insertions(+)
>  create mode 100644 drivers/iio/light/isl76683.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 2356ed9..4f0882c 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -194,6 +194,18 @@ config ISL29125
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called isl29125.
>  
> +config ISL76683
> +	tristate "Intersil ISL76683 light sensor"
> +	depends on I2C
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
> +	help
> +	  Say Y here if you want to build a driver for the Intersil ISL76683
> +	  light sensor for I2C.
> +
> +	  To compile this driver as a module, choose M here: the module will be
> +	  called isl76683.
> +
>  config HID_SENSOR_ALS
>  	depends on HID_SENSOR_HUB
>  	select IIO_BUFFER
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index fa32fa4..886a51f 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_HID_SENSOR_PROX)	+= hid-sensor-prox.o
>  obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
>  obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
>  obj-$(CONFIG_ISL29125)		+= isl29125.o
> +obj-$(CONFIG_ISL76683)		+= isl76683.o
>  obj-$(CONFIG_JSA1212)		+= jsa1212.o
>  obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
>  obj-$(CONFIG_LTR501)		+= ltr501.o
> diff --git a/drivers/iio/light/isl76683.c b/drivers/iio/light/isl76683.c
> new file mode 100644
> index 0000000..b730276
> --- /dev/null
> +++ b/drivers/iio/light/isl76683.c
> @@ -0,0 +1,693 @@
> +/*
> + * IIO driver for the light sensor ISL76683.
> + *
> + * Copyright (c) 2017 Christoph Fritz <chf.fritz@googlemail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * Datasheet:
> + *  http://www.intersil.com/content/dam/Intersil/documents/isl7/isl76683.pdf
> + */
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/util_macros.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +
> +#define ISL76683_REG_CMD		0x00
> +#define ISL76683_REG_CTRL		0x01
> +#define ISL76683_REG_THR_HI		0x02
> +#define ISL76683_REG_THR_LO		0x03
> +#define ISL76683_REG_SENSOR_L		0x04

maybe L -> LSB, M -> MSB to make it more clear
OTOH SENSOR_M is not really used, so could drop as well and maybe add a 
comment to denote that data is 16-bit little endian

> +#define ISL76683_REG_SENSOR_M		0x05
> +#define ISL76683_REG_CLEAR_INT		0x40
> +#define ISL76683_REGMAP_MAX		0x40
> +
> +#define ISL76683_CMD_ENABLE		BIT(7)
> +#define ISL76683_CMD_PWRDWN		BIT(6)
> +#define ISL76683_WIDTH_MASK		0x3
> +#define ISL76683_PHOTOD_SHFT		2
> +#define ISL76683_PHOTOD_MASK		(0x3 << ISL76683_PHOTOD_SHFT)

could use GENMASK()

> +#define ISL76683_INTPERS_MASK		0x3
> +#define ISL76683_LUXRANGE_SHFT		2
> +#define ISL76683_LUXRANGE_MASK		(0x3 << ISL76683_LUXRANGE_SHFT)
> +#define ISL76683_LUXRANGE_STR		"1000 4000 16000 64000"
> +
> +enum isl76683_dmode {
> +	ISL76683_DIODE_0 = 0,
> +	ISL76683_DIODE_IR,
> +	ISL76683_DIODE_DIFF,
> +};
> +
> +enum isl76683_lux_range {
> +	ISL76683_LUX_1000 = 0,
> +	ISL76683_LUX_4000,
> +	ISL76683_LUX_16000,
> +	ISL76683_LUX_64000,
> +};
> +
> +static const int isl76683_lux_ranges_available[] = {
> +	1000, 4000, 16000, 64000};
> +
> +#define ISL76683_LUX_RANGE_DEFAULT	ISL76683_LUX_1000
> +#define ISL76683_DIODE_MAX		ISL76683_DIODE_DIFF
> +#define ISL76683_DIODE_DEFAULT		ISL76683_DIODE_0
> +#define ISL76683_WIDTH_DEFAULT		0x0
> +#define ISL76683_RESOLUTION_DEFAULT	16
> +#define ISL76683_EXT_RESISTOR_DEFAULT	100
> +#define ISL76683_KOHM_MIN		1
> +#define ISL76683_KOHM_MAX		1000
> +#define ISL76683_INTPERS_DEFAULT	0x0
> +#define ISL76683_THR_DEFAULT		0x7f
> +
> +struct isl76683_chip {
> +	enum isl76683_lux_range	luxrange;
> +	int			external_resistor;
> +	enum isl76683_dmode	photodiode;
> +	struct i2c_client	*client;
> +	struct regmap		*rmp;
> +	struct completion	irq_complete;
> +	struct iio_trigger	*trig;
> +	bool			trig_enabled;
> +	struct mutex		lock;
> +	__le16			*buffer;

isl76683_trigger_handler() stores the already endianness-converted value 
into buffer, so type should be u16?

why do we need buffer at all?

> +	s64			time_ns;
> +	bool			buffer_running;
> +};
> +
> +static bool isl76683_readable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case ISL76683_REG_CMD:
> +	case ISL76683_REG_CTRL:
> +	case ISL76683_REG_THR_HI:
> +	case ISL76683_REG_THR_LO:
> +	case ISL76683_REG_SENSOR_L:
> +	case ISL76683_REG_SENSOR_M:
> +	case ISL76683_REG_CLEAR_INT:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool isl76683_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case ISL76683_REG_CMD:
> +	case ISL76683_REG_CTRL:
> +	case ISL76683_REG_THR_HI:
> +	case ISL76683_REG_THR_LO:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool isl76683_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case ISL76683_REG_SENSOR_L:
> +	case ISL76683_REG_SENSOR_M:
> +	case ISL76683_REG_CLEAR_INT:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config isl76683_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = ISL76683_REGMAP_MAX,
> +	.readable_reg = isl76683_readable_reg,
> +	.writeable_reg = isl76683_writeable_reg,
> +	.volatile_reg = isl76683_is_volatile_reg,
> +	.cache_type = REGCACHE_RBTREE,
> +};
> +
> +static int isl76683_set_config(struct isl76683_chip *chip)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CTRL,
> +				ISL76683_LUXRANGE_MASK | ISL76683_INTPERS_MASK,
> +				(chip->luxrange << ISL76683_LUXRANGE_SHFT) |
> +				ISL76683_INTPERS_DEFAULT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> +				ISL76683_PHOTOD_MASK | ISL76683_WIDTH_MASK,
> +				(chip->photodiode << ISL76683_PHOTOD_SHFT) |
> +				ISL76683_WIDTH_DEFAULT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_write(chip->rmp, ISL76683_REG_THR_HI,
> +				ISL76683_THR_DEFAULT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_write(chip->rmp, ISL76683_REG_THR_LO,
> +				ISL76683_THR_DEFAULT);

could just 
return regmap_write(...);

> +	if (ret < 0)
> +
> +	return 0;
> +}
> +
> +static int isl76683_power(struct isl76683_chip *chip, bool on)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> +				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
> +				0x0);
> +	if (ret < 0)
> +		return ret;

why are these bits first set to 0 and then bits are written with a 
separate command?
is this a requirement of the chip to clear and set?

> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> +				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
> +				on ? ISL76683_CMD_ENABLE : ISL76683_CMD_PWRDWN);
> +	if (ret < 0)
> +		return ret;
> +
> +	return on ? isl76683_set_config(chip) : 0;
> +}
> +
> +static int isl76683_reset(struct isl76683_chip *chip)
> +{
> +	int ret;
> +
> +	ret = isl76683_power(chip, false);
> +	if (ret < 0)
> +		return ret;

is an explicit delay needed here? just curious...

> +
> +	return isl76683_power(chip, true);
> +}
> +
> +static int isl76683_read_lux(struct isl76683_chip *chip,
> +			     bool is_processed, int *val)
> +{
> +	unsigned int sensor_data, range, fsr;
> +	__le16 sensor_raw;
> +	int ret;
> +
> +	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L,
> +				&sensor_raw, sizeof(sensor_raw));
> +	if (ret)
> +		return ret;
> +
> +	sensor_data = le16_to_cpu(sensor_raw);
> +
> +	if (!is_processed) {

in this case sensor_data is probably NOT in lux?
function name read_lux() is misleading?

> +		*val = sensor_data;
> +		return 0;
> +	}
> +
> +	/* range values taken from datasheet (table 9) */
> +	if (chip->luxrange == ISL76683_LUX_1000)
> +		range = 973;
> +	else if (chip->luxrange == ISL76683_LUX_4000)
> +		range = 3892;
> +	else if (chip->luxrange == ISL76683_LUX_16000)
> +		range = 15568;
> +	else if (chip->luxrange == ISL76683_LUX_64000)
> +		range = 62272;
> +	else
> +		return -EINVAL;
> +
> +	/* equations from datasheet (EQ.3 and EQ.4) */
> +	fsr = (100 * range) / chip->external_resistor;
> +	*val = (fsr * sensor_data) / (1 << ISL76683_RESOLUTION_DEFAULT);
> +
> +	return 0;
> +}
> +
> +static irqreturn_t isl76683_interrupt_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	chip->time_ns = iio_get_time_ns(indio_dev);
> +
> +	if (chip->trig_enabled)
> +		iio_trigger_poll(chip->trig);
> +
> +	if (!completion_done(&chip->irq_complete))
> +		complete(&chip->irq_complete);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static inline int isl76683_start_measurement(struct isl76683_chip *chip)
> +{
> +	int dummy;
> +
> +	/* dummy read is clearing irq and triggers new measurement */
> +	return regmap_read(chip->rmp, ISL76683_REG_CLEAR_INT, &dummy);
> +}
> +
> +static int isl76683_singleshot_conversion(struct isl76683_chip *chip,
> +					  const struct iio_chan_spec *chan,
> +					  bool is_processed, int *val)
> +{
> +	long timeout;
> +	int ret;
> +
> +	if (chip->buffer_running)
> +		return -EAGAIN;
> +
> +	switch (chan->channel2) {
> +	case IIO_MOD_LIGHT_BOTH:
> +		chip->photodiode = ISL76683_DIODE_DIFF;
> +		break;
> +	case IIO_MOD_LIGHT_IR:
> +		chip->photodiode = ISL76683_DIODE_IR;
> +		break;
> +	default:
> +		chip->photodiode = ISL76683_DIODE_0;
> +	}
> +
> +	ret = isl76683_set_config(chip);
> +	if (ret)
> +		return ret;
> +
> +	ret = isl76683_start_measurement(chip);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* wait for measurement to complete */
> +	timeout = wait_for_completion_interruptible_timeout(
> +			&chip->irq_complete,
> +			msecs_to_jiffies(5000));
> +	if (timeout == 0) {
> +		dev_err(&chip->client->dev, "measurement timed out\n");
> +		return -ETIMEDOUT;
> +	} else if (timeout < 0) {
> +		dev_err(&chip->client->dev, "wait for measurement failed\n");
> +		return -EINTR;
> +	}
> +
> +	ret = isl76683_read_lux(chip, is_processed, val);
> +	if (ret) {
> +		dev_err(&chip->client->dev, "%s: Error %d reading lux\n",
> +				__func__, ret);
> +		return ret;
> +	}
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static irqreturn_t isl76683_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +	__le16 buf;
> +	int ret;
> +
> +	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L, &buf, 2);

sizeof(buf)

> +	if (ret)
> +		return ret;
> +
> +	chip->buffer[0] = le16_to_cpu(buf);
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, chip->buffer,
> +					   chip->time_ns);
> +
> +	iio_trigger_notify_done(indio_dev->trig);
> +
> +	ret = isl76683_start_measurement(chip);
> +	if (ret < 0)
> +		return ret;

I think even if this fails IRQ_HANDLED should be returned

> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int isl76683_buffer_preenable(struct iio_dev *indio_dev)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	mutex_lock(&chip->lock);
> +	chip->buffer_running = true;
> +	mutex_unlock(&chip->lock);

should set_config() be also protected by the mutex?

> +	chip->photodiode = indio_dev->channels[0].channel2;
> +	return isl76683_set_config(chip);
> +}
> +
> +static int isl76683_buffer_postdisable(struct iio_dev *indio_dev)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	chip->buffer_running = false;
> +	return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops isl76683_buffer_setup_ops = {
> +	.preenable = &isl76683_buffer_preenable,
> +	.postdisable = &isl76683_buffer_postdisable,
> +	.predisable = iio_triggered_buffer_predisable,
> +	.postenable = iio_triggered_buffer_postenable,
> +	.validate_scan_mask = &iio_validate_scan_mask_onehot,
> +};
> +
> +static int isl76683_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val, int *val2, long mask)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		mutex_lock(&chip->lock);
> +		ret = isl76683_singleshot_conversion(chip, chan, false, val);
> +		mutex_unlock(&chip->lock);
> +		return ret;
> +	case IIO_CHAN_INFO_PROCESSED:
> +		mutex_lock(&chip->lock);
> +		ret = isl76683_singleshot_conversion(chip, chan, true, val);
> +		mutex_unlock(&chip->lock);
> +		return ret;
> +	case IIO_CHAN_INFO_HARDWAREGAIN:

use _SCALE?

> +		*val = isl76683_lux_ranges_available[chip->luxrange];
> +		return IIO_VAL_INT;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int isl76683_write_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int val, int val2, long mask)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_HARDWAREGAIN:
> +		mutex_lock(&chip->lock);
> +		chip->luxrange = find_closest(val,
> +			isl76683_lux_ranges_available,
> +			ARRAY_SIZE(isl76683_lux_ranges_available));
> +		ret = isl76683_set_config(chip);
> +		mutex_unlock(&chip->lock);
> +		return ret;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static IIO_CONST_ATTR(in_illuminance_hardwaregain_available,
> +		ISL76683_LUXRANGE_STR);
> +
> +static struct attribute *isl76683_attributes[] = {
> +	&iio_const_attr_in_illuminance_hardwaregain_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group isl76683_attribute_group = {
> +	.attrs = isl76683_attributes,
> +};
> +
> +#define ISL76683_CHANNEL_2(_ch2, _si) { \

why _2?

> +	.type = IIO_LIGHT, \
> +	.modified = 1, \
> +	.channel2 = _ch2, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			BIT(IIO_CHAN_INFO_PROCESSED), \

for INFO_RAW the measurement is not in lux, hence IIO_INTENSITY should be 
used? why have _RAW and _PROCESSED?

the computation in the _PROCESSED path should ideally go into the _SCALE 
factor


> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \

I think this should be _SCALE rather

> +	.scan_index = _si, \
> +	.scan_type = { \
> +		.sign = 'u', \
> +		.realbits = 16, \
> +		.storagebits = 16, \
> +		.endianness = IIO_CPU, \

you can/should specify IIO_LE and save the endianness conversion in 
isl76683_trigger_handler()

> +	}, \
> +}
> +
> +static const struct iio_chan_spec isl76683_channels[] = {
> +	{
> +		.type = IIO_LIGHT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +			BIT(IIO_CHAN_INFO_PROCESSED),
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN),
> +		.scan_index = 0,
> +		.scan_type = {
> +			.sign = 'u',
> +			.realbits = 16,
> +			.storagebits = 16,
> +			.endianness = IIO_CPU,
> +		},
> +	},
> +	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_IR, 1),
> +	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_BOTH, 2),
> +	IIO_CHAN_SOFT_TIMESTAMP(3),
> +};
> +
> +static int isl76683_update_scan_mode(struct iio_dev *indio_dev,
> +	const unsigned long *scan_mask)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	kfree(chip->buffer);
> +	chip->buffer = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);

most drivers do static allocation of the buffer, i.e. 2 bytes + 6 bytes 
padding + 8 bytes timestamp

> +	if (chip->buffer == NULL)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static const struct iio_info isl76683_info = {
> +	.update_scan_mode = isl76683_update_scan_mode,
> +	.read_raw = isl76683_read_raw,
> +	.write_raw = isl76683_write_raw,
> +	.attrs = &isl76683_attribute_group,
> +	.driver_module = THIS_MODULE,

THIS_MODULE not needed anymore

> +};
> +
> +static int isl76683_set_trigger_state(struct iio_trigger *trig, bool enable)
> +{
> +	struct isl76683_chip *chip = iio_trigger_get_drvdata(trig);
> +	int ret;
> +
> +	if (enable) {
> +		chip->trig_enabled = true;
> +		ret = isl76683_start_measurement(chip);
> +		if (ret < 0)
> +			return ret;
> +	} else
> +		chip->trig_enabled = false;
> +
> +	return 0;
> +}
> +
> +static const struct iio_trigger_ops isl76683_trigger_ops = {
> +	.owner = THIS_MODULE,
> +	.set_trigger_state = isl76683_set_trigger_state,
> +	.validate_device = iio_trigger_validate_own_device,
> +};
> +
> +static int isl76683_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	struct isl76683_chip *chip;
> +	struct iio_dev *indio_dev;
> +	struct device_node *np = client->dev.of_node;
> +	int rs = ISL76683_EXT_RESISTOR_DEFAULT;
> +	int v, ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	chip = iio_priv(indio_dev);
> +
> +	i2c_set_clientdata(client, indio_dev);
> +	chip->client = client;
> +
> +	if (np) {
> +		ret = of_property_read_u32(np, "isil,external-resistor", &v);
> +		if (ret || v < ISL76683_KOHM_MIN || v > ISL76683_KOHM_MAX)
> +			dev_warn(&client->dev,
> +				 "assuming %i kOhm resistor\n", rs);

I'd rather fail if the value is incorrect (matter of taste)

> +		else
> +			rs = v;
> +	}
> +
> +	chip->luxrange = ISL76683_LUX_RANGE_DEFAULT;
> +	chip->external_resistor = rs;
> +	chip->photodiode = ISL76683_DIODE_DEFAULT;
> +	chip->buffer_running = false;
> +
> +	chip->rmp = devm_regmap_init_i2c(client, &isl76683_regmap_config);
> +	if (IS_ERR(chip->rmp)) {
> +		ret = PTR_ERR(chip->rmp);
> +		dev_err(&client->dev, "%s: Error %d initializing regmap\n",
> +			__func__, ret);
> +		return ret;
> +	}
> +
> +	mutex_init(&chip->lock);
> +
> +	init_completion(&chip->irq_complete);
> +
> +	if (!client->irq) {
> +		dev_err(&client->dev, "no interrupt configured\n");
> +		return -EINVAL;
> +	}
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &isl76683_info;
> +	indio_dev->channels = isl76683_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(isl76683_channels);
> +	indio_dev->name = id->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	chip->trig_enabled = false;
> +	chip->trig = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
> +			indio_dev->name, indio_dev->id);
> +	if (!chip->trig)
> +		return -ENOMEM;
> +
> +	chip->trig->ops = &isl76683_trigger_ops;
> +	chip->trig->dev.parent = &client->dev;
> +	iio_trigger_set_drvdata(chip->trig, chip);
> +
> +	ret = devm_request_irq(&client->dev, client->irq,
> +			isl76683_interrupt_handler,
> +			IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +			"isl76683_event", indio_dev);
> +	if (ret) {
> +		dev_err(&client->dev, "irq request error\n");
> +		return ret;
> +	}
> +
> +	ret = devm_iio_trigger_register(&client->dev, chip->trig);
> +	if (ret) {
> +		dev_err(&client->dev, "iio_trigger register error\n");
> +		return ret;
> +	}
> +
> +	ret = isl76683_reset(chip);
> +	if (ret) {
> +		dev_err(&client->dev, "reset failed\n");
> +		return ret;
> +	}
> +
> +	ret = isl76683_read_lux(chip, false, &v);
> +	if (ret) {
> +		dev_err(&client->dev, "initial dummy readout failed\n");
> +		return ret;
> +	}
> +
> +	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
> +			&isl76683_trigger_handler, &isl76683_buffer_setup_ops);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_iio_device_register(&client->dev, indio_dev);
> +	if (ret) {
> +		dev_err(&client->dev,
> +			"%s(): iio registration failed with error %d\n",
> +			__func__, ret);
> +		return ret;
> +	}
> +
> +	return ret;
> +}
> +
> +static int isl76683_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +	isl76683_power(chip, false);
> +	kfree(chip->buffer);
> +
> +	return 0;
> +}
> +
> +#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM)
> +static int isl76683_runtime_suspend(struct device *dev)
> +{
> +	struct isl76683_chip *chip =
> +		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +	int ret;
> +
> +	mutex_lock(&chip->lock);
> +	ret = isl76683_power(chip, false);
> +	regcache_mark_dirty(chip->rmp);
> +	mutex_unlock(&chip->lock);
> +
> +	return ret;
> +}
> +
> +static int isl76683_runtime_resume(struct device *dev)
> +{
> +	struct isl76683_chip *chip =
> +		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +	int ret;
> +
> +	mutex_lock(&chip->lock);
> +	ret = isl76683_power(chip, true);
> +	mutex_unlock(&chip->lock);
> +
> +	return ret;
> +}
> +#endif
> +
> +static const struct dev_pm_ops isl76683_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +				pm_runtime_force_resume)
> +	SET_RUNTIME_PM_OPS(isl76683_runtime_suspend,
> +			   isl76683_runtime_resume, NULL)
> +};
> +
> +static const struct i2c_device_id isl76683_id[] = {
> +	{"isl76683", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, isl76683_id);
> +
> +static const struct of_device_id isl76683_of_match[] = {
> +	{ .compatible = "isil,isl76683", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, isl76683_of_match);
> +
> +static struct i2c_driver isl76683_driver = {
> +	.driver  = {
> +		.name = "isl76683",
> +		.of_match_table = isl76683_of_match,
> +		.pm = &isl76683_pm_ops,
> +	},
> +	.probe = isl76683_probe,
> +	.remove = isl76683_remove,
> +	.id_table = isl76683_id,
> +};
> +
> +module_i2c_driver(isl76683_driver);
> +
> +MODULE_DESCRIPTION("ISL76683 Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Christoph Fritz <chf.fritz@googlemail.com>");
> 

-- 

Peter Meerwald-Stadler
Mobile: +43 664 24 44 418

Re: [PATCH 1/3] iio: light: add support for Intersil isl76683 sensor

[Christoph Fritz]

Hi Peter,

 thanks for your input, please see my comments and questions below.

On Tue, 2017-11-07 at 17:28 +0100, Peter Meerwald-Stadler wrote:
> On Tue, 7 Nov 2017, Christoph Fritz wrote:
> 
> > This patch adds support for Intersil isl76683 light sensor.
> 
> nitpicking in subject: maybe 'Add support...', start uppercase 
> more comments below

OK

>  
> > Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
> > ---
> >  drivers/iio/light/Kconfig    |  12 +
> >  drivers/iio/light/Makefile   |   1 +
> >  drivers/iio/light/isl76683.c | 693 +++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 706 insertions(+)
> >  create mode 100644 drivers/iio/light/isl76683.c
> > 
> > diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> > index 2356ed9..4f0882c 100644
> > --- a/drivers/iio/light/Kconfig
> > +++ b/drivers/iio/light/Kconfig
> > @@ -194,6 +194,18 @@ config ISL29125
> >  	  To compile this driver as a module, choose M here: the module will be
> >  	  called isl29125.
> >  
> > +config ISL76683
> > +	tristate "Intersil ISL76683 light sensor"
> > +	depends on I2C
> > +	select IIO_BUFFER
> > +	select IIO_TRIGGERED_BUFFER
> > +	help
> > +	  Say Y here if you want to build a driver for the Intersil ISL76683
> > +	  light sensor for I2C.
> > +
> > +	  To compile this driver as a module, choose M here: the module will be
> > +	  called isl76683.
> > +
> >  config HID_SENSOR_ALS
> >  	depends on HID_SENSOR_HUB
> >  	select IIO_BUFFER
> > diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> > index fa32fa4..886a51f 100644
> > --- a/drivers/iio/light/Makefile
> > +++ b/drivers/iio/light/Makefile
> > @@ -22,6 +22,7 @@ obj-$(CONFIG_HID_SENSOR_PROX)	+= hid-sensor-prox.o
> >  obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
> >  obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
> >  obj-$(CONFIG_ISL29125)		+= isl29125.o
> > +obj-$(CONFIG_ISL76683)		+= isl76683.o
> >  obj-$(CONFIG_JSA1212)		+= jsa1212.o
> >  obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
> >  obj-$(CONFIG_LTR501)		+= ltr501.o
> > diff --git a/drivers/iio/light/isl76683.c b/drivers/iio/light/isl76683.c
> > new file mode 100644
> > index 0000000..b730276
> > --- /dev/null
> > +++ b/drivers/iio/light/isl76683.c
> > @@ -0,0 +1,693 @@
> > +/*
> > + * IIO driver for the light sensor ISL76683.
> > + *
> > + * Copyright (c) 2017 Christoph Fritz <chf.fritz@googlemail.com>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful, but WITHOUT
> > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> > + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> > + * more details.
> > + *
> > + * Datasheet:
> > + *  http://www.intersil.com/content/dam/Intersil/documents/isl7/isl76683.pdf
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/i2c.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/regmap.h>
> > +#include <linux/util_macros.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > +#include <linux/iio/buffer.h>
> > +#include <linux/iio/trigger.h>
> > +#include <linux/iio/trigger_consumer.h>
> > +#include <linux/iio/triggered_buffer.h>
> > +
> > +#define ISL76683_REG_CMD		0x00
> > +#define ISL76683_REG_CTRL		0x01
> > +#define ISL76683_REG_THR_HI		0x02
> > +#define ISL76683_REG_THR_LO		0x03
> > +#define ISL76683_REG_SENSOR_L		0x04
> 
> maybe L -> LSB, M -> MSB to make it more clear
> OTOH SENSOR_M is not really used, so could drop as well and maybe add a 
> comment to denote that data is 16-bit little endian

I'll change it to ISL76683_REG_SENSOR_LSB and _MSB

ISL76683_REG_SENSOR_MSB is used in regmap readable and volatile
definition and is read by

 regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_LSB,
                                &sensor_raw, sizeof(sensor_raw));

because sizeof(sensor_raw) is 2

> 
> > +#define ISL76683_REG_SENSOR_M		0x05
> > +#define ISL76683_REG_CLEAR_INT		0x40
> > +#define ISL76683_REGMAP_MAX		0x40
> > +
> > +#define ISL76683_CMD_ENABLE		BIT(7)
> > +#define ISL76683_CMD_PWRDWN		BIT(6)
> > +#define ISL76683_WIDTH_MASK		0x3
> > +#define ISL76683_PHOTOD_SHFT		2
> > +#define ISL76683_PHOTOD_MASK		(0x3 << ISL76683_PHOTOD_SHFT)
> 
> could use GENMASK()

OK

> 
> > +#define ISL76683_INTPERS_MASK		0x3
> > +#define ISL76683_LUXRANGE_SHFT		2
> > +#define ISL76683_LUXRANGE_MASK		(0x3 << ISL76683_LUXRANGE_SHFT)
> > +#define ISL76683_LUXRANGE_STR		"1000 4000 16000 64000"
> > +
> > +enum isl76683_dmode {
> > +	ISL76683_DIODE_0 = 0,
> > +	ISL76683_DIODE_IR,
> > +	ISL76683_DIODE_DIFF,
> > +};
> > +
> > +enum isl76683_lux_range {
> > +	ISL76683_LUX_1000 = 0,
> > +	ISL76683_LUX_4000,
> > +	ISL76683_LUX_16000,
> > +	ISL76683_LUX_64000,
> > +};
> > +
> > +static const int isl76683_lux_ranges_available[] = {
> > +	1000, 4000, 16000, 64000};
> > +
> > +#define ISL76683_LUX_RANGE_DEFAULT	ISL76683_LUX_1000
> > +#define ISL76683_DIODE_MAX		ISL76683_DIODE_DIFF
> > +#define ISL76683_DIODE_DEFAULT		ISL76683_DIODE_0
> > +#define ISL76683_WIDTH_DEFAULT		0x0
> > +#define ISL76683_RESOLUTION_DEFAULT	16
> > +#define ISL76683_EXT_RESISTOR_DEFAULT	100
> > +#define ISL76683_KOHM_MIN		1
> > +#define ISL76683_KOHM_MAX		1000
> > +#define ISL76683_INTPERS_DEFAULT	0x0
> > +#define ISL76683_THR_DEFAULT		0x7f
> > +
> > +struct isl76683_chip {
> > +	enum isl76683_lux_range	luxrange;
> > +	int			external_resistor;
> > +	enum isl76683_dmode	photodiode;
> > +	struct i2c_client	*client;
> > +	struct regmap		*rmp;
> > +	struct completion	irq_complete;
> > +	struct iio_trigger	*trig;
> > +	bool			trig_enabled;
> > +	struct mutex		lock;
> > +	__le16			*buffer;
> 
> isl76683_trigger_handler() stores the already endianness-converted value 
> into buffer, so type should be u16?

OK

> why do we need buffer at all?

to keep the buffer data small in either case when
scan_elements/timestamp is used or not, see isl76683_update_scan_mode()

> > +	s64			time_ns;
> > +	bool			buffer_running;
> > +};
> > +
> > +static bool isl76683_readable_reg(struct device *dev, unsigned int reg)
> > +{
> > +	switch (reg) {
> > +	case ISL76683_REG_CMD:
> > +	case ISL76683_REG_CTRL:
> > +	case ISL76683_REG_THR_HI:
> > +	case ISL76683_REG_THR_LO:
> > +	case ISL76683_REG_SENSOR_L:
> > +	case ISL76683_REG_SENSOR_M:
> > +	case ISL76683_REG_CLEAR_INT:
> > +		return true;
> > +	default:
> > +		return false;
> > +	}
> > +}
> > +
> > +static bool isl76683_writeable_reg(struct device *dev, unsigned int reg)
> > +{
> > +	switch (reg) {
> > +	case ISL76683_REG_CMD:
> > +	case ISL76683_REG_CTRL:
> > +	case ISL76683_REG_THR_HI:
> > +	case ISL76683_REG_THR_LO:
> > +		return true;
> > +	default:
> > +		return false;
> > +	}
> > +}
> > +
> > +static bool isl76683_is_volatile_reg(struct device *dev, unsigned int reg)
> > +{
> > +	switch (reg) {
> > +	case ISL76683_REG_SENSOR_L:
> > +	case ISL76683_REG_SENSOR_M:
> > +	case ISL76683_REG_CLEAR_INT:
> > +		return true;
> > +	default:
> > +		return false;
> > +	}
> > +}
> > +
> > +static const struct regmap_config isl76683_regmap_config = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +	.max_register = ISL76683_REGMAP_MAX,
> > +	.readable_reg = isl76683_readable_reg,
> > +	.writeable_reg = isl76683_writeable_reg,
> > +	.volatile_reg = isl76683_is_volatile_reg,
> > +	.cache_type = REGCACHE_RBTREE,
> > +};
> > +
> > +static int isl76683_set_config(struct isl76683_chip *chip)
> > +{
> > +	int ret;
> > +
> > +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CTRL,
> > +				ISL76683_LUXRANGE_MASK | ISL76683_INTPERS_MASK,
> > +				(chip->luxrange << ISL76683_LUXRANGE_SHFT) |
> > +				ISL76683_INTPERS_DEFAULT);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> > +				ISL76683_PHOTOD_MASK | ISL76683_WIDTH_MASK,
> > +				(chip->photodiode << ISL76683_PHOTOD_SHFT) |
> > +				ISL76683_WIDTH_DEFAULT);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = regmap_write(chip->rmp, ISL76683_REG_THR_HI,
> > +				ISL76683_THR_DEFAULT);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = regmap_write(chip->rmp, ISL76683_REG_THR_LO,
> > +				ISL76683_THR_DEFAULT);
> 
> could just 
> return regmap_write(...);

ok, but then it looks like this because of 80 chars max per line:

        return regmap_write(chip->rmp, ISL76683_REG_THR_LO,
                            chip->threshold_low);
}

> 
> > +	if (ret < 0)
> > +
> > +	return 0;
> > +}
> > +
> > +static int isl76683_power(struct isl76683_chip *chip, bool on)
> > +{
> > +	int ret;
> > +
> > +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> > +				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
> > +				0x0);
> > +	if (ret < 0)
> > +		return ret;
> 
> why are these bits first set to 0 and then bits are written with a 
> separate command?
> is this a requirement of the chip to clear and set?

yes, that's the "proper" way as the data-sheet (page 9, bullet 2.)
recommends.

> 
> > +
> > +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> > +				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
> > +				on ? ISL76683_CMD_ENABLE : ISL76683_CMD_PWRDWN);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return on ? isl76683_set_config(chip) : 0;
> > +}
> > +
> > +static int isl76683_reset(struct isl76683_chip *chip)
> > +{
> > +	int ret;
> > +
> > +	ret = isl76683_power(chip, false);
> > +	if (ret < 0)
> > +		return ret;
> 
> is an explicit delay needed here? just curious...

nope, haven't found any info in the data-sheet which would recommend any
delay and here it works fine for me

> 
> > +
> > +	return isl76683_power(chip, true);
> > +}
> > +
> > +static int isl76683_read_lux(struct isl76683_chip *chip,
> > +			     bool is_processed, int *val)
> > +{
> > +	unsigned int sensor_data, range, fsr;
> > +	__le16 sensor_raw;
> > +	int ret;
> > +
> > +	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L,
> > +				&sensor_raw, sizeof(sensor_raw));
> > +	if (ret)
> > +		return ret;
> > +
> > +	sensor_data = le16_to_cpu(sensor_raw);
> > +
> > +	if (!is_processed) {
> 
> in this case sensor_data is probably NOT in lux?
> function name read_lux() is misleading?

is isl76683_get_sensordata() better?

> 
> > +		*val = sensor_data;
> > +		return 0;
> > +	}
> > +
> > +	/* range values taken from datasheet (table 9) */
> > +	if (chip->luxrange == ISL76683_LUX_1000)
> > +		range = 973;
> > +	else if (chip->luxrange == ISL76683_LUX_4000)
> > +		range = 3892;
> > +	else if (chip->luxrange == ISL76683_LUX_16000)
> > +		range = 15568;
> > +	else if (chip->luxrange == ISL76683_LUX_64000)
> > +		range = 62272;
> > +	else
> > +		return -EINVAL;
> > +
> > +	/* equations from datasheet (EQ.3 and EQ.4) */
> > +	fsr = (100 * range) / chip->external_resistor;
> > +	*val = (fsr * sensor_data) / (1 << ISL76683_RESOLUTION_DEFAULT);
> > +
> > +	return 0;
> > +}

<snip>

> > +
> > +static irqreturn_t isl76683_trigger_handler(int irq, void *p)
> > +{
> > +	struct iio_poll_func *pf = p;
> > +	struct iio_dev *indio_dev = pf->indio_dev;
> > +	struct isl76683_chip *chip = iio_priv(indio_dev);
> > +	__le16 buf;
> > +	int ret;
> > +
> > +	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L, &buf, 2);
> 
> sizeof(buf)

OK

I used 2 to fit into 80 chars

> 
> > +	if (ret)
> > +		return ret;
> > +
> > +	chip->buffer[0] = le16_to_cpu(buf);
> > +
> > +	iio_push_to_buffers_with_timestamp(indio_dev, chip->buffer,
> > +					   chip->time_ns);
> > +
> > +	iio_trigger_notify_done(indio_dev->trig);
> > +
> > +	ret = isl76683_start_measurement(chip);
> > +	if (ret < 0)
> > +		return ret;
> 
> I think even if this fails IRQ_HANDLED should be returned

OK

> 
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int isl76683_buffer_preenable(struct iio_dev *indio_dev)
> > +{
> > +	struct isl76683_chip *chip = iio_priv(indio_dev);
> > +
> > +	mutex_lock(&chip->lock);
> > +	chip->buffer_running = true;
> > +	mutex_unlock(&chip->lock);
> 
> should set_config() be also protected by the mutex?

OK

> 
> > +	chip->photodiode = indio_dev->channels[0].channel2;
> > +	return isl76683_set_config(chip);
> > +}
> > +
> > +static int isl76683_buffer_postdisable(struct iio_dev *indio_dev)
> > +{
> > +	struct isl76683_chip *chip = iio_priv(indio_dev);
> > +
> > +	chip->buffer_running = false;
> > +	return 0;
> > +}
> > +
> > +static const struct iio_buffer_setup_ops isl76683_buffer_setup_ops = {
> > +	.preenable = &isl76683_buffer_preenable,
> > +	.postdisable = &isl76683_buffer_postdisable,
> > +	.predisable = iio_triggered_buffer_predisable,
> > +	.postenable = iio_triggered_buffer_postenable,
> > +	.validate_scan_mask = &iio_validate_scan_mask_onehot,
> > +};
> > +
> > +static int isl76683_read_raw(struct iio_dev *indio_dev,
> > +			     struct iio_chan_spec const *chan,
> > +			     int *val, int *val2, long mask)
> > +{
> > +	struct isl76683_chip *chip = iio_priv(indio_dev);
> > +	int ret;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		mutex_lock(&chip->lock);
> > +		ret = isl76683_singleshot_conversion(chip, chan, false, val);
> > +		mutex_unlock(&chip->lock);
> > +		return ret;
> > +	case IIO_CHAN_INFO_PROCESSED:
> > +		mutex_lock(&chip->lock);
> > +		ret = isl76683_singleshot_conversion(chip, chan, true, val);
> > +		mutex_unlock(&chip->lock);
> > +		return ret;
> > +	case IIO_CHAN_INFO_HARDWAREGAIN:
> 
> use _SCALE?

OK

> 
> > +		*val = isl76683_lux_ranges_available[chip->luxrange];
> > +		return IIO_VAL_INT;
> > +	}
> > +
> > +	return -EINVAL;
> > +}
> > +
> > +static int isl76683_write_raw(struct iio_dev *indio_dev,
> > +			     struct iio_chan_spec const *chan,
> > +			     int val, int val2, long mask)
> > +{
> > +	struct isl76683_chip *chip = iio_priv(indio_dev);
> > +	int ret;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_HARDWAREGAIN:
> > +		mutex_lock(&chip->lock);
> > +		chip->luxrange = find_closest(val,
> > +			isl76683_lux_ranges_available,
> > +			ARRAY_SIZE(isl76683_lux_ranges_available));
> > +		ret = isl76683_set_config(chip);
> > +		mutex_unlock(&chip->lock);
> > +		return ret;
> > +	}
> > +
> > +	return -EINVAL;
> > +}
> > +
> > +static IIO_CONST_ATTR(in_illuminance_hardwaregain_available,
> > +		ISL76683_LUXRANGE_STR);
> > +
> > +static struct attribute *isl76683_attributes[] = {
> > +	&iio_const_attr_in_illuminance_hardwaregain_available.dev_attr.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group isl76683_attribute_group = {
> > +	.attrs = isl76683_attributes,
> > +};
> > +
> > +#define ISL76683_CHANNEL_2(_ch2, _si) { \
> 
> why _2?

to be more clear about what the purpose here is: "setting channel 2".
But obviously this doesn't work :) ... so I'll change it to
ISL76683_CHANNEL

> 
> > +	.type = IIO_LIGHT, \
> > +	.modified = 1, \
> > +	.channel2 = _ch2, \
> > +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> > +			BIT(IIO_CHAN_INFO_PROCESSED), \
> 
> for INFO_RAW the measurement is not in lux, hence IIO_INTENSITY should be 
> used? why have _RAW and _PROCESSED?
> 
> the computation in the _PROCESSED path should ideally go into the _SCALE 
> factor
> 
> 
> > +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
> 
> I think this should be _SCALE rather
> 
> > +	.scan_index = _si, \
> > +	.scan_type = { \
> > +		.sign = 'u', \
> > +		.realbits = 16, \
> > +		.storagebits = 16, \
> > +		.endianness = IIO_CPU, \
> 
> you can/should specify IIO_LE and save the endianness conversion in 
> isl76683_trigger_handler()

So buffer should still be __le16* and not u16*?

> 
> > +	}, \
> > +}
> > +
> > +static const struct iio_chan_spec isl76683_channels[] = {
> > +	{
> > +		.type = IIO_LIGHT,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> > +			BIT(IIO_CHAN_INFO_PROCESSED),
> > +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN),
> > +		.scan_index = 0,
> > +		.scan_type = {
> > +			.sign = 'u',
> > +			.realbits = 16,
> > +			.storagebits = 16,
> > +			.endianness = IIO_CPU,
> > +		},
> > +	},
> > +	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_IR, 1),
> > +	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_BOTH, 2),
> > +	IIO_CHAN_SOFT_TIMESTAMP(3),
> > +};
> > +
> > +static int isl76683_update_scan_mode(struct iio_dev *indio_dev,
> > +	const unsigned long *scan_mask)
> > +{
> > +	struct isl76683_chip *chip = iio_priv(indio_dev);
> > +
> > +	kfree(chip->buffer);
> > +	chip->buffer = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
> 
> most drivers do static allocation of the buffer, i.e. 2 bytes + 6 bytes 
> padding + 8 bytes timestamp

is this a "have to"?

> 
> > +	if (chip->buffer == NULL)
> > +		return -ENOMEM;
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct iio_info isl76683_info = {
> > +	.update_scan_mode = isl76683_update_scan_mode,
> > +	.read_raw = isl76683_read_raw,
> > +	.write_raw = isl76683_write_raw,
> > +	.attrs = &isl76683_attribute_group,
> > +	.driver_module = THIS_MODULE,
> 
> THIS_MODULE not needed anymore

OK

> 
> > +};
> > +
> > +static int isl76683_set_trigger_state(struct iio_trigger *trig, bool enable)
> > +{
> > +	struct isl76683_chip *chip = iio_trigger_get_drvdata(trig);
> > +	int ret;
> > +
> > +	if (enable) {
> > +		chip->trig_enabled = true;
> > +		ret = isl76683_start_measurement(chip);
> > +		if (ret < 0)
> > +			return ret;
> > +	} else
> > +		chip->trig_enabled = false;
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct iio_trigger_ops isl76683_trigger_ops = {
> > +	.owner = THIS_MODULE,
> > +	.set_trigger_state = isl76683_set_trigger_state,
> > +	.validate_device = iio_trigger_validate_own_device,
> > +};
> > +
> > +static int isl76683_probe(struct i2c_client *client,
> > +			  const struct i2c_device_id *id)
> > +{
> > +	struct isl76683_chip *chip;
> > +	struct iio_dev *indio_dev;
> > +	struct device_node *np = client->dev.of_node;
> > +	int rs = ISL76683_EXT_RESISTOR_DEFAULT;
> > +	int v, ret;
> > +
> > +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	chip = iio_priv(indio_dev);
> > +
> > +	i2c_set_clientdata(client, indio_dev);
> > +	chip->client = client;
> > +
> > +	if (np) {
> > +		ret = of_property_read_u32(np, "isil,external-resistor", &v);
> > +		if (ret || v < ISL76683_KOHM_MIN || v > ISL76683_KOHM_MAX)
> > +			dev_warn(&client->dev,
> > +				 "assuming %i kOhm resistor\n", rs);
> 
> I'd rather fail if the value is incorrect (matter of taste)

it's only for IIO_CHAN_INFO_PROCESSED, so I like it to let it slide:
Okay for you?

<snip>

Re: [PATCH 1/3] iio: light: add support for Intersil isl76683 sensor

[Jonathan Cameron]

On Tue, 7 Nov 2017 16:36:21 +0100
Christoph Fritz <chf.fritz@googlemail.com> wrote:

> This patch adds support for Intersil isl76683 light sensor.
> 
> Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
Sorry, bit of a rushed review as boarding about to start for a transatlantic flight...

Anyhow, a few comments inline in addition to Peter's. I'll take a proper look at V2.

Jonathan
> ---
>  drivers/iio/light/Kconfig    |  12 +
>  drivers/iio/light/Makefile   |   1 +
>  drivers/iio/light/isl76683.c | 693 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 706 insertions(+)
>  create mode 100644 drivers/iio/light/isl76683.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 2356ed9..4f0882c 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -194,6 +194,18 @@ config ISL29125
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called isl29125.
>  
> +config ISL76683
> +	tristate "Intersil ISL76683 light sensor"
> +	depends on I2C
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
> +	help
> +	  Say Y here if you want to build a driver for the Intersil ISL76683
> +	  light sensor for I2C.
> +
> +	  To compile this driver as a module, choose M here: the module will be
> +	  called isl76683.
> +
>  config HID_SENSOR_ALS
>  	depends on HID_SENSOR_HUB
>  	select IIO_BUFFER
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index fa32fa4..886a51f 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_HID_SENSOR_PROX)	+= hid-sensor-prox.o
>  obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o
>  obj-$(CONFIG_SENSORS_ISL29028)	+= isl29028.o
>  obj-$(CONFIG_ISL29125)		+= isl29125.o
> +obj-$(CONFIG_ISL76683)		+= isl76683.o
>  obj-$(CONFIG_JSA1212)		+= jsa1212.o
>  obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
>  obj-$(CONFIG_LTR501)		+= ltr501.o
> diff --git a/drivers/iio/light/isl76683.c b/drivers/iio/light/isl76683.c
> new file mode 100644
> index 0000000..b730276
> --- /dev/null
> +++ b/drivers/iio/light/isl76683.c
> @@ -0,0 +1,693 @@
> +/*
> + * IIO driver for the light sensor ISL76683.
> + *
> + * Copyright (c) 2017 Christoph Fritz <chf.fritz@googlemail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * Datasheet:
> + *  http://www.intersil.com/content/dam/Intersil/documents/isl7/isl76683.pdf
> + */
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/util_macros.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +
> +#define ISL76683_REG_CMD		0x00
> +#define ISL76683_REG_CTRL		0x01
> +#define ISL76683_REG_THR_HI		0x02
> +#define ISL76683_REG_THR_LO		0x03
> +#define ISL76683_REG_SENSOR_L		0x04
> +#define ISL76683_REG_SENSOR_M		0x05
> +#define ISL76683_REG_CLEAR_INT		0x40
> +#define ISL76683_REGMAP_MAX		0x40
> +
> +#define ISL76683_CMD_ENABLE		BIT(7)
> +#define ISL76683_CMD_PWRDWN		BIT(6)
> +#define ISL76683_WIDTH_MASK		0x3
> +#define ISL76683_PHOTOD_SHFT		2
> +#define ISL76683_PHOTOD_MASK		(0x3 << ISL76683_PHOTOD_SHFT)
> +#define ISL76683_INTPERS_MASK		0x3
> +#define ISL76683_LUXRANGE_SHFT		2
> +#define ISL76683_LUXRANGE_MASK		(0x3 << ISL76683_LUXRANGE_SHFT)
> +#define ISL76683_LUXRANGE_STR		"1000 4000 16000 64000"
> +
> +enum isl76683_dmode {
> +	ISL76683_DIODE_0 = 0,
> +	ISL76683_DIODE_IR,
> +	ISL76683_DIODE_DIFF,
> +};
> +
> +enum isl76683_lux_range {
> +	ISL76683_LUX_1000 = 0,
> +	ISL76683_LUX_4000,
> +	ISL76683_LUX_16000,
> +	ISL76683_LUX_64000,
> +};
> +
> +static const int isl76683_lux_ranges_available[] = {
> +	1000, 4000, 16000, 64000};
> +
> +#define ISL76683_LUX_RANGE_DEFAULT	ISL76683_LUX_1000
> +#define ISL76683_DIODE_MAX		ISL76683_DIODE_DIFF
> +#define ISL76683_DIODE_DEFAULT		ISL76683_DIODE_0
> +#define ISL76683_WIDTH_DEFAULT		0x0
> +#define ISL76683_RESOLUTION_DEFAULT	16
> +#define ISL76683_EXT_RESISTOR_DEFAULT	100
> +#define ISL76683_KOHM_MIN		1
> +#define ISL76683_KOHM_MAX		1000
> +#define ISL76683_INTPERS_DEFAULT	0x0
> +#define ISL76683_THR_DEFAULT		0x7f
> +
> +struct isl76683_chip {
> +	enum isl76683_lux_range	luxrange;
> +	int			external_resistor;
> +	enum isl76683_dmode	photodiode;
> +	struct i2c_client	*client;
> +	struct regmap		*rmp;
> +	struct completion	irq_complete;
> +	struct iio_trigger	*trig;
> +	bool			trig_enabled;
> +	struct mutex		lock;
> +	__le16			*buffer;
> +	s64			time_ns;
> +	bool			buffer_running;
> +};
> +
> +static bool isl76683_readable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case ISL76683_REG_CMD:
> +	case ISL76683_REG_CTRL:
> +	case ISL76683_REG_THR_HI:
> +	case ISL76683_REG_THR_LO:
> +	case ISL76683_REG_SENSOR_L:
> +	case ISL76683_REG_SENSOR_M:
> +	case ISL76683_REG_CLEAR_INT:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool isl76683_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case ISL76683_REG_CMD:
> +	case ISL76683_REG_CTRL:
> +	case ISL76683_REG_THR_HI:
> +	case ISL76683_REG_THR_LO:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool isl76683_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case ISL76683_REG_SENSOR_L:
> +	case ISL76683_REG_SENSOR_M:
> +	case ISL76683_REG_CLEAR_INT:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config isl76683_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = ISL76683_REGMAP_MAX,
> +	.readable_reg = isl76683_readable_reg,
> +	.writeable_reg = isl76683_writeable_reg,
> +	.volatile_reg = isl76683_is_volatile_reg,
> +	.cache_type = REGCACHE_RBTREE,
> +};
> +
> +static int isl76683_set_config(struct isl76683_chip *chip)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CTRL,
> +				ISL76683_LUXRANGE_MASK | ISL76683_INTPERS_MASK,
> +				(chip->luxrange << ISL76683_LUXRANGE_SHFT) |
> +				ISL76683_INTPERS_DEFAULT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> +				ISL76683_PHOTOD_MASK | ISL76683_WIDTH_MASK,
> +				(chip->photodiode << ISL76683_PHOTOD_SHFT) |
> +				ISL76683_WIDTH_DEFAULT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_write(chip->rmp, ISL76683_REG_THR_HI,
> +				ISL76683_THR_DEFAULT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_write(chip->rmp, ISL76683_REG_THR_LO,
> +				ISL76683_THR_DEFAULT);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int isl76683_power(struct isl76683_chip *chip, bool on)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> +				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
> +				0x0);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_update_bits(chip->rmp, ISL76683_REG_CMD,
> +				ISL76683_CMD_ENABLE | ISL76683_CMD_PWRDWN,
> +				on ? ISL76683_CMD_ENABLE : ISL76683_CMD_PWRDWN);
> +	if (ret < 0)
> +		return ret;
> +
> +	return on ? isl76683_set_config(chip) : 0;
> +}
> +
> +static int isl76683_reset(struct isl76683_chip *chip)
> +{
> +	int ret;
> +
> +	ret = isl76683_power(chip, false);
> +	if (ret < 0)
> +		return ret;
> +
> +	return isl76683_power(chip, true);
> +}
> +
> +static int isl76683_read_lux(struct isl76683_chip *chip,
> +			     bool is_processed, int *val)
> +{
> +	unsigned int sensor_data, range, fsr;
> +	__le16 sensor_raw;
> +	int ret;
> +
> +	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L,
> +				&sensor_raw, sizeof(sensor_raw));
> +	if (ret)
> +		return ret;
> +
> +	sensor_data = le16_to_cpu(sensor_raw);
> +
> +	if (!is_processed) {
> +		*val = sensor_data;
> +		return 0;
> +	}
> +
> +	/* range values taken from datasheet (table 9) */
> +	if (chip->luxrange == ISL76683_LUX_1000)
> +		range = 973;
> +	else if (chip->luxrange == ISL76683_LUX_4000)
> +		range = 3892;
> +	else if (chip->luxrange == ISL76683_LUX_16000)
> +		range = 15568;
> +	else if (chip->luxrange == ISL76683_LUX_64000)
> +		range = 62272;
> +	else
> +		return -EINVAL;
> +
> +	/* equations from datasheet (EQ.3 and EQ.4) */
> +	fsr = (100 * range) / chip->external_resistor;
> +	*val = (fsr * sensor_data) / (1 << ISL76683_RESOLUTION_DEFAULT);
> +
> +	return 0;
> +}
> +
> +static irqreturn_t isl76683_interrupt_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	chip->time_ns = iio_get_time_ns(indio_dev);
> +
> +	if (chip->trig_enabled)
> +		iio_trigger_poll(chip->trig);
> +
> +	if (!completion_done(&chip->irq_complete))
> +		complete(&chip->irq_complete);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static inline int isl76683_start_measurement(struct isl76683_chip *chip)
> +{
> +	int dummy;
> +
> +	/* dummy read is clearing irq and triggers new measurement */
> +	return regmap_read(chip->rmp, ISL76683_REG_CLEAR_INT, &dummy);
> +}
> +
> +static int isl76683_singleshot_conversion(struct isl76683_chip *chip,
> +					  const struct iio_chan_spec *chan,
> +					  bool is_processed, int *val)
> +{
> +	long timeout;
> +	int ret;
> +
> +	if (chip->buffer_running)
Don't reinvent the wheel.  (this is racy btw).

iio_claim_direct_mode etc will do this in a non racy fashion for you.
> +		return -EAGAIN;
> +
> +	switch (chan->channel2) {
> +	case IIO_MOD_LIGHT_BOTH:
> +		chip->photodiode = ISL76683_DIODE_DIFF;
> +		break;
> +	case IIO_MOD_LIGHT_IR:
> +		chip->photodiode = ISL76683_DIODE_IR;
> +		break;
> +	default:
> +		chip->photodiode = ISL76683_DIODE_0;
> +	}
> +
> +	ret = isl76683_set_config(chip);
> +	if (ret)
> +		return ret;
> +
> +	ret = isl76683_start_measurement(chip);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* wait for measurement to complete */
> +	timeout = wait_for_completion_interruptible_timeout(
> +			&chip->irq_complete,
> +			msecs_to_jiffies(5000));
> +	if (timeout == 0) {
> +		dev_err(&chip->client->dev, "measurement timed out\n");
> +		return -ETIMEDOUT;
> +	} else if (timeout < 0) {
> +		dev_err(&chip->client->dev, "wait for measurement failed\n");
> +		return -EINTR;
> +	}
> +
> +	ret = isl76683_read_lux(chip, is_processed, val);
> +	if (ret) {
> +		dev_err(&chip->client->dev, "%s: Error %d reading lux\n",
> +				__func__, ret);
> +		return ret;
> +	}
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static irqreturn_t isl76683_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +	__le16 buf;
> +	int ret;
> +
> +	ret = regmap_bulk_read(chip->rmp, ISL76683_REG_SENSOR_L, &buf, 2);
> +	if (ret)
> +		return ret;
> +
> +	chip->buffer[0] = le16_to_cpu(buf);
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, chip->buffer,
> +					   chip->time_ns);
> +
> +	iio_trigger_notify_done(indio_dev->trig);
> +
> +	ret = isl76683_start_measurement(chip);
> +	if (ret < 0)
> +		return ret;
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int isl76683_buffer_preenable(struct iio_dev *indio_dev)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	mutex_lock(&chip->lock);
> +	chip->buffer_running = true;
> +	mutex_unlock(&chip->lock);
> +	chip->photodiode = indio_dev->channels[0].channel2;
> +	return isl76683_set_config(chip);
> +}
> +
> +static int isl76683_buffer_postdisable(struct iio_dev *indio_dev)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	chip->buffer_running = false;
> +	return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops isl76683_buffer_setup_ops = {
> +	.preenable = &isl76683_buffer_preenable,
> +	.postdisable = &isl76683_buffer_postdisable,
> +	.predisable = iio_triggered_buffer_predisable,
> +	.postenable = iio_triggered_buffer_postenable,
> +	.validate_scan_mask = &iio_validate_scan_mask_onehot,
> +};
> +
> +static int isl76683_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val, int *val2, long mask)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		mutex_lock(&chip->lock);
> +		ret = isl76683_singleshot_conversion(chip, chan, false, val);
> +		mutex_unlock(&chip->lock);
> +		return ret;
> +	case IIO_CHAN_INFO_PROCESSED:
> +		mutex_lock(&chip->lock);
> +		ret = isl76683_singleshot_conversion(chip, chan, true, val);
> +		mutex_unlock(&chip->lock);
> +		return ret;
> +	case IIO_CHAN_INFO_HARDWAREGAIN:
> +		*val = isl76683_lux_ranges_available[chip->luxrange];
> +		return IIO_VAL_INT;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int isl76683_write_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int val, int val2, long mask)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_HARDWAREGAIN:
> +		mutex_lock(&chip->lock);
> +		chip->luxrange = find_closest(val,
> +			isl76683_lux_ranges_available,
> +			ARRAY_SIZE(isl76683_lux_ranges_available));
> +		ret = isl76683_set_config(chip);
> +		mutex_unlock(&chip->lock);
> +		return ret;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static IIO_CONST_ATTR(in_illuminance_hardwaregain_available,
> +		ISL76683_LUXRANGE_STR);
> +
> +static struct attribute *isl76683_attributes[] = {
> +	&iio_const_attr_in_illuminance_hardwaregain_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group isl76683_attribute_group = {
> +	.attrs = isl76683_attributes,
> +};
> +
> +#define ISL76683_CHANNEL_2(_ch2, _si) { \
> +	.type = IIO_LIGHT, \
> +	.modified = 1, \
> +	.channel2 = _ch2, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			BIT(IIO_CHAN_INFO_PROCESSED), \
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
> +	.scan_index = _si, \
> +	.scan_type = { \
> +		.sign = 'u', \
> +		.realbits = 16, \
> +		.storagebits = 16, \
> +		.endianness = IIO_CPU, \
> +	}, \
> +}
> +
> +static const struct iio_chan_spec isl76683_channels[] = {
> +	{
> +		.type = IIO_LIGHT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +			BIT(IIO_CHAN_INFO_PROCESSED),
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN),
> +		.scan_index = 0,
> +		.scan_type = {
> +			.sign = 'u',
> +			.realbits = 16,
> +			.storagebits = 16,
> +			.endianness = IIO_CPU,
> +		},
> +	},
> +	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_IR, 1),
> +	ISL76683_CHANNEL_2(IIO_MOD_LIGHT_BOTH, 2),
> +	IIO_CHAN_SOFT_TIMESTAMP(3),
> +};
> +
> +static int isl76683_update_scan_mode(struct iio_dev *indio_dev,
> +	const unsigned long *scan_mask)
> +{
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	kfree(chip->buffer);
> +	chip->buffer = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
> +	if (chip->buffer == NULL)
> +		return -ENOMEM;

I would be lazy and just make the buffer big enough for all cases.
You will want to play the __cachline_aligned game to make it
dma safe at the end of the chip structure.

> +
> +	return 0;
> +}
> +
> +static const struct iio_info isl76683_info = {
> +	.update_scan_mode = isl76683_update_scan_mode,
> +	.read_raw = isl76683_read_raw,
> +	.write_raw = isl76683_write_raw,
> +	.attrs = &isl76683_attribute_group,
> +	.driver_module = THIS_MODULE,
This will not work with latest IIO tree (or linux-next)
Just drop setting this field as it no longer exists.

> +};
> +
> +static int isl76683_set_trigger_state(struct iio_trigger *trig, bool enable)
> +{
> +	struct isl76683_chip *chip = iio_trigger_get_drvdata(trig);
> +	int ret;
> +
> +	if (enable) {
> +		chip->trig_enabled = true;

This is unusual enough that I'd like a comment here on how you would end
up in a state where this is necessary.

> +		ret = isl76683_start_measurement(chip);
> +		if (ret < 0)
> +			return ret;
> +	} else
> +		chip->trig_enabled = false;
> +
> +	return 0;
> +}
> +
> +static const struct iio_trigger_ops isl76683_trigger_ops = {
> +	.owner = THIS_MODULE,
> +	.set_trigger_state = isl76683_set_trigger_state,
> +	.validate_device = iio_trigger_validate_own_device,
> +};
> +
> +static int isl76683_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	struct isl76683_chip *chip;
> +	struct iio_dev *indio_dev;
> +	struct device_node *np = client->dev.of_node;
> +	int rs = ISL76683_EXT_RESISTOR_DEFAULT;
> +	int v, ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	chip = iio_priv(indio_dev);
> +
> +	i2c_set_clientdata(client, indio_dev);
> +	chip->client = client;
> +
> +	if (np) {
> +		ret = of_property_read_u32(np, "isil,external-resistor", &v);
> +		if (ret || v < ISL76683_KOHM_MIN || v > ISL76683_KOHM_MAX)
> +			dev_warn(&client->dev,
> +				 "assuming %i kOhm resistor\n", rs);
> +		else
> +			rs = v;
> +	}
> +
> +	chip->luxrange = ISL76683_LUX_RANGE_DEFAULT;
> +	chip->external_resistor = rs;
> +	chip->photodiode = ISL76683_DIODE_DEFAULT;
> +	chip->buffer_running = false;
> +
> +	chip->rmp = devm_regmap_init_i2c(client, &isl76683_regmap_config);
> +	if (IS_ERR(chip->rmp)) {
> +		ret = PTR_ERR(chip->rmp);
> +		dev_err(&client->dev, "%s: Error %d initializing regmap\n",
> +			__func__, ret);
> +		return ret;
> +	}
> +
> +	mutex_init(&chip->lock);
> +
> +	init_completion(&chip->irq_complete);
> +
> +	if (!client->irq) {
> +		dev_err(&client->dev, "no interrupt configured\n");
> +		return -EINVAL;
> +	}
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &isl76683_info;
> +	indio_dev->channels = isl76683_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(isl76683_channels);
> +	indio_dev->name = id->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	chip->trig_enabled = false;
> +	chip->trig = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
> +			indio_dev->name, indio_dev->id);
> +	if (!chip->trig)
> +		return -ENOMEM;
> +
> +	chip->trig->ops = &isl76683_trigger_ops;
> +	chip->trig->dev.parent = &client->dev;
> +	iio_trigger_set_drvdata(chip->trig, chip);
> +
> +	ret = devm_request_irq(&client->dev, client->irq,
> +			isl76683_interrupt_handler,
> +			IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +			"isl76683_event", indio_dev);
> +	if (ret) {
> +		dev_err(&client->dev, "irq request error\n");
> +		return ret;
> +	}
> +
> +	ret = devm_iio_trigger_register(&client->dev, chip->trig);
> +	if (ret) {
> +		dev_err(&client->dev, "iio_trigger register error\n");
> +		return ret;
> +	}
> +
> +	ret = isl76683_reset(chip);
> +	if (ret) {
> +		dev_err(&client->dev, "reset failed\n");
> +		return ret;
> +	}
> +
> +	ret = isl76683_read_lux(chip, false, &v);
> +	if (ret) {
> +		dev_err(&client->dev, "initial dummy readout failed\n");
> +		return ret;
> +	}
> +
> +	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
> +			&isl76683_trigger_handler, &isl76683_buffer_setup_ops);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_iio_device_register(&client->dev, indio_dev);
> +	if (ret) {
> +		dev_err(&client->dev,
> +			"%s(): iio registration failed with error %d\n",
> +			__func__, ret);
> +		return ret;
Drop this return ret.

> +	}
> +
> +	return ret;
> +}
> +
> +static int isl76683_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct isl76683_chip *chip = iio_priv(indio_dev);
> +
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +	isl76683_power(chip, false);
> +	kfree(chip->buffer);
> +
> +	return 0;
> +}
> +
> +#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM)
> +static int isl76683_runtime_suspend(struct device *dev)
> +{
> +	struct isl76683_chip *chip =
> +		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +	int ret;
> +
> +	mutex_lock(&chip->lock);
> +	ret = isl76683_power(chip, false);
> +	regcache_mark_dirty(chip->rmp);
> +	mutex_unlock(&chip->lock);
> +
> +	return ret;
> +}
> +
> +static int isl76683_runtime_resume(struct device *dev)
> +{
> +	struct isl76683_chip *chip =
> +		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +	int ret;
> +
> +	mutex_lock(&chip->lock);
> +	ret = isl76683_power(chip, true);
> +	mutex_unlock(&chip->lock);
> +
> +	return ret;
> +}
> +#endif
> +
> +static const struct dev_pm_ops isl76683_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +				pm_runtime_force_resume)
> +	SET_RUNTIME_PM_OPS(isl76683_runtime_suspend,
> +			   isl76683_runtime_resume, NULL)
> +};
> +
> +static const struct i2c_device_id isl76683_id[] = {
> +	{"isl76683", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, isl76683_id);
> +
> +static const struct of_device_id isl76683_of_match[] = {
> +	{ .compatible = "isil,isl76683", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, isl76683_of_match);
> +
> +static struct i2c_driver isl76683_driver = {
> +	.driver  = {
> +		.name = "isl76683",
> +		.of_match_table = isl76683_of_match,
> +		.pm = &isl76683_pm_ops,
> +	},
> +	.probe = isl76683_probe,
> +	.remove = isl76683_remove,
> +	.id_table = isl76683_id,
> +};
> +
> +module_i2c_driver(isl76683_driver);
> +
> +MODULE_DESCRIPTION("ISL76683 Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Christoph Fritz <chf.fritz@googlemail.com>");

[PATCH 2/3] dt-bindings: iio: add Intersil isl76683 light sensor bindings

[Christoph Fritz]

This patch adds documentation of device tree bindings for Intersil
isl76683 light sensor.

Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
---
 .../devicetree/bindings/iio/light/isl76683.txt     | 26 ++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/isl76683.txt

diff --git a/Documentation/devicetree/bindings/iio/light/isl76683.txt b/Documentation/devicetree/bindings/iio/light/isl76683.txt
new file mode 100644
index 0000000..657f17d
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/light/isl76683.txt
@@ -0,0 +1,26 @@
+* ISL76683 ambient light sensor
+
+http://www.intersil.com/content/dam/Intersil/documents/isl7/isl76683.pdf
+
+Required properties:
+
+  - compatible: must be "isil,isl76683"
+  - reg: the I2C address of the sensor
+  - interrupt-parent: should be the phandle for the interrupt controller
+  - interrupts: interrupt mapping for GPIO IRQ
+
+Optional properties:
+
+  - isil,external-resistor: integer in kOhm of external resistor R_ext.
+                            Valid values are from 1 to 1000.
+                            If not supplied, 100 kOhm will be assumed.
+
+Example:
+
+isl76683@44 {
+	compatible = "isil,isl76683";
+	reg = <0x44>;
+	interrupt-parent = <&gpio1>;
+	interrupts = <20 IRQ_TYPE_LEVEL_LOW>;
+	isil,external-resistor = <50>;
+};
-- 
2.1.4

Re: [PATCH 2/3] dt-bindings: iio: add Intersil isl76683 light sensor bindings

[Rob Herring]

On Tue, Nov 07, 2017 at 04:36:22PM +0100, Christoph Fritz wrote:
> This patch adds documentation of device tree bindings for Intersil
> isl76683 light sensor.
> 
> Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
> ---
>  .../devicetree/bindings/iio/light/isl76683.txt     | 26 ++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/light/isl76683.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/light/isl76683.txt b/Documentation/devicetree/bindings/iio/light/isl76683.txt
> new file mode 100644
> index 0000000..657f17d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/light/isl76683.txt
> @@ -0,0 +1,26 @@
> +* ISL76683 ambient light sensor
> +
> +http://www.intersil.com/content/dam/Intersil/documents/isl7/isl76683.pdf
> +
> +Required properties:
> +
> +  - compatible: must be "isil,isl76683"
> +  - reg: the I2C address of the sensor
> +  - interrupt-parent: should be the phandle for the interrupt controller
> +  - interrupts: interrupt mapping for GPIO IRQ
> +
> +Optional properties:
> +
> +  - isil,external-resistor: integer in kOhm of external resistor R_ext.
> +                            Valid values are from 1 to 1000.
> +                            If not supplied, 100 kOhm will be assumed.

Add an unit suffix as defined in property-units.txt.

> +
> +Example:
> +
> +isl76683@44 {
> +	compatible = "isil,isl76683";
> +	reg = <0x44>;
> +	interrupt-parent = <&gpio1>;
> +	interrupts = <20 IRQ_TYPE_LEVEL_LOW>;
> +	isil,external-resistor = <50>;
> +};
> -- 
> 2.1.4
> 

Re: [PATCH 2/3] dt-bindings: iio: add Intersil isl76683 light sensor bindings

[Christoph Fritz]

Hi Rob

On Fri, 2017-11-10 at 15:26 -0600, Rob Herring wrote:
> On Tue, Nov 07, 2017 at 04:36:22PM +0100, Christoph Fritz wrote:

> > +Optional properties:
> > +
> > +  - isil,external-resistor: integer in kOhm of external resistor R_ext.
> > +                            Valid values are from 1 to 1000.
> > +                            If not supplied, 100 kOhm will be assumed.
> 
> Add an unit suffix as defined in property-units.txt.

Thanks, I'll use "isil,external-resistor-ohms" as defined in
property-units.txt.

What bothers me a bit is that there is no "-kilo-ohms" suffix but a
"-micro-ohms" which is pretty uncommon. Even the only use of suffix
"-micro-ohms" could have been expressed easily as "-ohms" while being
more readable:

qcom,external-resistor-micro-ohms = <10000>;

Due to stable dt-api I suppose this cannot be changed and/or extended
with "-kilo-ohms", right?

Thanks
 -- Christoph

[PATCH 3/3] iio: light: isl76683 add way to adjust irq threshold

[Christoph Fritz]

This patch adds sysfs read/write support for upper and lower irq
thresholds. So it's possible that only on certain lux ranges the
irq triggered measurement happens.

Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
---
 .../ABI/testing/sysfs-bus-iio-light-isl76683       | 17 +++++++
 drivers/iio/light/isl76683.c                       | 58 ++++++++++++++++++++--
 2 files changed, 71 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-light-isl76683

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-light-isl76683 b/Documentation/ABI/testing/sysfs-bus-iio-light-isl76683
new file mode 100644
index 0000000..c7e08d7
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-light-isl76683
@@ -0,0 +1,17 @@
+What:		/sys/bus/iio/devices/iio:deviceX/in_illuminance_threshold_low
+Date:		November 2017
+KernelVersion:	4.15.0
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Raw value of lower threshold for the interrupt.
+		Reading returns 8-bit MSB data of a 16-bit threshold.
+		Writing 0...255 represents 8-bit MSB data of a 16-bit threshold.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_illuminance_threshold_up
+Date:		November 2017
+KernelVersion:	4.15.0
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Raw value of upper threshold for the interrupt.
+		Reading returns 8-bit MSB data of a 16-bit threshold.
+		Writing 0...255 represents 8-bit MSB data of a 16-bit threshold.
diff --git a/drivers/iio/light/isl76683.c b/drivers/iio/light/isl76683.c
index b730276..889fb85 100644
--- a/drivers/iio/light/isl76683.c
+++ b/drivers/iio/light/isl76683.c
@@ -74,11 +74,14 @@ static const int isl76683_lux_ranges_available[] = {
 #define ISL76683_KOHM_MAX		1000
 #define ISL76683_INTPERS_DEFAULT	0x0
 #define ISL76683_THR_DEFAULT		0x7f
+#define ISL76683_THR_MAX		0xFF
 
 struct isl76683_chip {
 	enum isl76683_lux_range	luxrange;
 	int			external_resistor;
 	enum isl76683_dmode	photodiode;
+	int			threshold_up;
+	int			threshold_low;
 	struct i2c_client	*client;
 	struct regmap		*rmp;
 	struct completion	irq_complete;
@@ -159,13 +162,11 @@ static int isl76683_set_config(struct isl76683_chip *chip)
 	if (ret < 0)
 		return ret;
 
-	ret = regmap_write(chip->rmp, ISL76683_REG_THR_HI,
-				ISL76683_THR_DEFAULT);
+	ret = regmap_write(chip->rmp, ISL76683_REG_THR_HI, chip->threshold_up);
 	if (ret < 0)
 		return ret;
 
-	ret = regmap_write(chip->rmp, ISL76683_REG_THR_LO,
-				ISL76683_THR_DEFAULT);
+	ret = regmap_write(chip->rmp, ISL76683_REG_THR_LO, chip->threshold_low);
 	if (ret < 0)
 		return ret;
 
@@ -415,11 +416,58 @@ static int isl76683_write_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+#define ISL76683_SYSFS_STORE(ident, _max)				\
+static ssize_t in_illuminance_##ident##_store(struct device *dev,	\
+					struct device_attribute *attr,	\
+					const char *buf, size_t len)	\
+{									\
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);		\
+	struct isl76683_chip *chip = iio_priv(indio_dev);		\
+	unsigned int val;						\
+	int ret;							\
+									\
+	if (kstrtouint(buf, 10, &val))					\
+		return -EINVAL;						\
+									\
+	if (val > _max)							\
+		return -EINVAL;						\
+									\
+	mutex_lock(&chip->lock);					\
+	chip->ident = val;						\
+	ret = isl76683_set_config(chip);				\
+	mutex_unlock(&chip->lock);					\
+									\
+	if (ret)							\
+		return -EIO;						\
+									\
+	return len;							\
+}
+
+ISL76683_SYSFS_STORE(threshold_low, ISL76683_THR_MAX)
+ISL76683_SYSFS_STORE(threshold_up, ISL76683_THR_MAX)
+
+#define ISL76683_SYSFS_SHOW(ident, show_val)				\
+static ssize_t in_illuminance_##ident##_show(struct device *dev,	\
+			struct device_attribute *attr, char *buf)	\
+{									\
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);		\
+	struct isl76683_chip *chip = iio_priv(indio_dev);		\
+									\
+	return snprintf(buf, PAGE_SIZE, "%i\n", show_val);		\
+}
+
+ISL76683_SYSFS_SHOW(threshold_up, chip->threshold_up)
+ISL76683_SYSFS_SHOW(threshold_low, chip->threshold_low)
+
 static IIO_CONST_ATTR(in_illuminance_hardwaregain_available,
 		ISL76683_LUXRANGE_STR);
+static IIO_DEVICE_ATTR_RW(in_illuminance_threshold_up, 0);
+static IIO_DEVICE_ATTR_RW(in_illuminance_threshold_low, 0);
 
 static struct attribute *isl76683_attributes[] = {
 	&iio_const_attr_in_illuminance_hardwaregain_available.dev_attr.attr,
+	&iio_dev_attr_in_illuminance_threshold_up.dev_attr.attr,
+	&iio_dev_attr_in_illuminance_threshold_low.dev_attr.attr,
 	NULL
 };
 
@@ -535,6 +583,8 @@ static int isl76683_probe(struct i2c_client *client,
 	chip->luxrange = ISL76683_LUX_RANGE_DEFAULT;
 	chip->external_resistor = rs;
 	chip->photodiode = ISL76683_DIODE_DEFAULT;
+	chip->threshold_up = ISL76683_THR_DEFAULT;
+	chip->threshold_low = ISL76683_THR_DEFAULT;
 	chip->buffer_running = false;
 
 	chip->rmp = devm_regmap_init_i2c(client, &isl76683_regmap_config);
-- 
2.1.4