staging: iio: light: Adding driver for ISL29018 ALS

adding support for the ISL 29018 ambient light and proximity sensor.

Addressed comments from reviews by Jonathan Cameron and Joe Perches
  * Removed some excess dbg prints that only printed function name
  * Renamed some properties to make them more descriptive
  * Added a property to list available adc resolutions
  * Defined arrays for resolutions/ranges as static const
  * Change loops initialization to memset for extensibility.
    * used sizeof() instead of ARRAY_SIZE() to be safer
  * Added a property to list available adc ranges
  * Fixed warnings and property names.

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/Documentation/sysfs-bus-iio-light

@@ -0,0 +1,64 @@
+
+What:		/sys/bus/iio/devices/device[n]/range
+KernelVersion:	2.6.37
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Hardware dependent ADC Full Scale Range used for some ambient
+		light sensors in calculating lux.
+
+What:		/sys/bus/iio/devices/device[n]/range_available
+KernelVersion:	2.6.37
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Hardware dependent supported vales for ADC Full Scale Range.
+
+What:		/sys/bus/iio/devices/device[n]/adc_resolution
+KernelVersion:	2.6.37
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Hardware dependent ADC resolution of the ambient light sensor
+		used in calculating the lux.
+
+What:		/sys/bus/iio/devices/device[n]/adc_resolution_available
+KernelVersion:	2.6.37
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Hardware dependent list of possible values supported for the
+		adc_resolution of the given sensor.
+
+What:		/sys/bus/iio/devices/device[n]/illuminance0[_input|_raw]
+KernelVersion:	2.6.35
+Contact:	linux-iio@vger.kernel.org
+Description:
+		This should return the calculated lux from the light sensor. If
+		it comes back in SI units, it should also include _input else it
+		should include _raw to signify it is not in SI units.
+
+What:		/sys/.../device[n]/proximity_on_chip_ambient_infrared_supression
+KernelVersion:	2.6.37
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Hardware dependent mode for an ALS device to calculate the value
+		in proximity mode. When this is enabled, then the device should
+		use a infrared sensor reading to remove infrared noise from the
+		proximity reading. If this is not enabled, the driver can still
+		do this calculation manually by reading the infrared sensor
+		value and doing the negation in sw.
+
+What:		/sys/bus/iio/devices/device[n]/proximity[_input|_raw]
+KernelVersion:	2.6.37
+Contact:	linux-iio@vger.kernel.org
+Description:
+		This property is supported by proximity sensors and should be
+		used to return the value of a reading by the sensor. If this
+		value is returned in SI units, it should also include _input
+		but if it is not, then it should include _raw.
+
+What:		/sys/bus/iio/devices/device[n]/intensity_infrared[_input|_raw]
+KernelVersion:	2.6.37
+Contact:	linux-iio@vger.kernel.org
+Description:
+		This property is supported by sensors that have an infrared
+		sensing mode. This value should be the output from a reading
+		and if expressed in SI units, should include _input. If this
+		value is not in SI units, then it should include _raw.

drivers/staging/iio/light/Kconfig

@@ -12,3 +12,15 @@ config SENSORS_TSL2563
 
 	 This driver can also be built as a module.  If so, the module
 	 will be called tsl2563.
+
+config SENSORS_ISL29018
+        tristate "ISL 29018 light and proximity sensor"
+        depends on I2C
+        default n
+        help
+         If you say yes here you get support for ambient light sensing and
+         proximity infrared sensing from Intersil ISL29018.
+         This driver will provide the measurements of ambient light intensity
+         in lux, proximity infrared sensing and normal infrared sensing.
+         Data from sensor is accessible via sysfs.
+

drivers/staging/iio/light/Makefile

@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o
+obj-$(CONFIG_SENSORS_ISL29018)	+= isl29018.o

drivers/staging/iio/light/isl29018.c

@@ -0,0 +1,563 @@
+/*
+ * A iio driver for the light sensor ISL 29018.
+ *
+ * IIO driver for monitoring ambient light intensity in luxi, proximity
+ * sensing and infrared sensing.
+ *
+ * Copyright (c) 2010, NVIDIA Corporation.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA	02110-1301, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include "../iio.h"
+
+#define CONVERSION_TIME_MS		100
+
+#define ISL29018_REG_ADD_COMMAND1	0x00
+#define COMMMAND1_OPMODE_SHIFT		5
+#define COMMMAND1_OPMODE_MASK		(7 << COMMMAND1_OPMODE_SHIFT)
+#define COMMMAND1_OPMODE_POWER_DOWN	0
+#define COMMMAND1_OPMODE_ALS_ONCE	1
+#define COMMMAND1_OPMODE_IR_ONCE	2
+#define COMMMAND1_OPMODE_PROX_ONCE	3
+
+#define ISL29018_REG_ADD_COMMANDII	0x01
+#define COMMANDII_RESOLUTION_SHIFT	2
+#define COMMANDII_RESOLUTION_MASK	(0x3 << COMMANDII_RESOLUTION_SHIFT)
+
+#define COMMANDII_RANGE_SHIFT		0
+#define COMMANDII_RANGE_MASK		(0x3 << COMMANDII_RANGE_SHIFT)
+
+#define COMMANDII_SCHEME_SHIFT		7
+#define COMMANDII_SCHEME_MASK		(0x1 << COMMANDII_SCHEME_SHIFT)
+
+#define ISL29018_REG_ADD_DATA_LSB	0x02
+#define ISL29018_REG_ADD_DATA_MSB	0x03
+#define ISL29018_MAX_REGS		ISL29018_REG_ADD_DATA_MSB
+
+struct isl29018_chip {
+	struct iio_dev		*indio_dev;
+	struct i2c_client	*client;
+	struct mutex		lock;
+	unsigned int		range;
+	unsigned int		adc_bit;
+	int			prox_scheme;
+	u8			reg_cache[ISL29018_MAX_REGS];
+};
+
+static int isl29018_write_data(struct i2c_client *client, u8 reg,
+			u8 val, u8 mask, u8 shift)
+{
+	u8 regval;
+	int ret = 0;
+	struct isl29018_chip *chip = i2c_get_clientdata(client);
+
+	regval = chip->reg_cache[reg];
+	regval &= ~mask;
+	regval |= val << shift;
+
+	ret = i2c_smbus_write_byte_data(client, reg, regval);
+	if (ret) {
+		dev_err(&client->dev, "Write to device fails status %x\n", ret);
+		return ret;
+	}
+	chip->reg_cache[reg] = regval;
+
+	return 0;
+}
+
+static int isl29018_set_range(struct i2c_client *client, unsigned long range,
+		unsigned int *new_range)
+{
+	static const unsigned long supp_ranges[] = {1000, 4000, 16000, 64000};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(supp_ranges); ++i) {
+		if (range <= supp_ranges[i]) {
+			*new_range = (unsigned int)supp_ranges[i];
+			break;
+		}
+	}
+
+	if (i >= ARRAY_SIZE(supp_ranges))
+		return -EINVAL;
+
+	return isl29018_write_data(client, ISL29018_REG_ADD_COMMANDII,
+			i, COMMANDII_RANGE_MASK, COMMANDII_RANGE_SHIFT);
+}
+
+static int isl29018_set_resolution(struct i2c_client *client,
+			unsigned long adcbit, unsigned int *conf_adc_bit)
+{
+	static const unsigned long supp_adcbit[] = {16, 12, 8, 4};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(supp_adcbit); ++i) {
+		if (adcbit >= supp_adcbit[i]) {
+			*conf_adc_bit = (unsigned int)supp_adcbit[i];
+			break;
+		}
+	}
+
+	if (i >= ARRAY_SIZE(supp_adcbit))
+		return -EINVAL;
+
+	return isl29018_write_data(client, ISL29018_REG_ADD_COMMANDII,
+			i, COMMANDII_RESOLUTION_MASK,
+			COMMANDII_RESOLUTION_SHIFT);
+}
+
+static int isl29018_read_sensor_input(struct i2c_client *client, int mode)
+{
+	int status;
+	int lsb;
+	int msb;
+
+	/* Set mode */
+	status = isl29018_write_data(client, ISL29018_REG_ADD_COMMAND1,
+			mode, COMMMAND1_OPMODE_MASK, COMMMAND1_OPMODE_SHIFT);
+	if (status) {
+		dev_err(&client->dev, "Error in setting operating mode\n");
+		return status;
+	}
+	msleep(CONVERSION_TIME_MS);
+	lsb = i2c_smbus_read_byte_data(client, ISL29018_REG_ADD_DATA_LSB);
+	if (lsb < 0) {
+		dev_err(&client->dev, "Error in reading LSB DATA\n");
+		return lsb;
+	}
+
+	msb = i2c_smbus_read_byte_data(client, ISL29018_REG_ADD_DATA_MSB);
+	if (msb < 0) {
+		dev_err(&client->dev, "Error in reading MSB DATA\n");
+		return msb;
+	}
+	dev_vdbg(&client->dev, "MSB 0x%x and LSB 0x%x\n", msb, lsb);
+
+	return (msb << 8) | lsb;
+}
+
+static int isl29018_read_lux(struct i2c_client *client, int *lux)
+{
+	int lux_data;
+	struct isl29018_chip *chip = i2c_get_clientdata(client);
+
+	lux_data = isl29018_read_sensor_input(client,
+				COMMMAND1_OPMODE_ALS_ONCE);
+
+	if (lux_data < 0)
+		return lux_data;
+
+	*lux = (lux_data * chip->range) >> chip->adc_bit;
+
+	return 0;
+}
+
+static int isl29018_read_ir(struct i2c_client *client, int *ir)
+{
+	int ir_data;
+
+	ir_data = isl29018_read_sensor_input(client, COMMMAND1_OPMODE_IR_ONCE);
+
+	if (ir_data < 0)
+		return ir_data;
+
+	*ir = ir_data;
+
+	return 0;
+}
+
+static int isl29018_read_proximity_ir(struct i2c_client *client, int scheme,
+		int *near_ir)
+{
+	int status;
+	int prox_data = -1;
+	int ir_data = -1;
+
+	/* Do proximity sensing with required scheme */
+	status = isl29018_write_data(client, ISL29018_REG_ADD_COMMANDII,
+			scheme, COMMANDII_SCHEME_MASK, COMMANDII_SCHEME_SHIFT);
+	if (status) {
+		dev_err(&client->dev, "Error in setting operating mode\n");
+		return status;
+	}
+
+	prox_data = isl29018_read_sensor_input(client,
+					COMMMAND1_OPMODE_PROX_ONCE);
+	if (prox_data < 0)
+		return prox_data;
+
+	if (scheme == 1) {
+		*near_ir = prox_data;
+		return 0;
+	}
+
+	ir_data = isl29018_read_sensor_input(client,
+				COMMMAND1_OPMODE_IR_ONCE);
+
+	if (ir_data < 0)
+		return ir_data;
+
+	if (prox_data >= ir_data)
+		*near_ir = prox_data - ir_data;
+	else
+		*near_ir = 0;
+
+	return 0;
+}
+
+static ssize_t get_sensor_data(struct device *dev, char *buf, int mode)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+	struct i2c_client *client = chip->client;
+	int value = 0;
+	int status;
+
+	mutex_lock(&chip->lock);
+	switch (mode) {
+	case COMMMAND1_OPMODE_PROX_ONCE:
+		status = isl29018_read_proximity_ir(client,
+				chip->prox_scheme, &value);
+		break;
+
+	case COMMMAND1_OPMODE_ALS_ONCE:
+		status = isl29018_read_lux(client, &value);
+		break;
+
+	case COMMMAND1_OPMODE_IR_ONCE:
+		status = isl29018_read_ir(client, &value);
+		break;
+
+	default:
+		dev_err(&client->dev, "Mode %d is not supported\n", mode);
+		mutex_unlock(&chip->lock);
+		return -EBUSY;
+	}
+	if (status < 0) {
+		dev_err(&client->dev, "Error in Reading data");
+		mutex_unlock(&chip->lock);
+		return status;
+	}
+
+	mutex_unlock(&chip->lock);
+
+	return sprintf(buf, "%d\n", value);
+}
+
+/* Sysfs interface */
+/* range */
+static ssize_t show_range(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+
+	return sprintf(buf, "%u\n", chip->range);
+}
+
+static ssize_t store_range(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+	struct i2c_client *client = chip->client;
+	int status;
+	unsigned long lval;
+	unsigned int new_range;
+
+	if (strict_strtoul(buf, 10, &lval))
+		return -EINVAL;
+
+	if (!(lval == 1000UL || lval == 4000UL ||
+			lval == 16000UL || lval == 64000UL)) {
+		dev_err(dev, "The range is not supported\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&chip->lock);
+	status = isl29018_set_range(client, lval, &new_range);
+	if (status < 0) {
+		mutex_unlock(&chip->lock);
+		dev_err(dev, "Error in setting max range\n");
+		return status;
+	}
+	chip->range = new_range;
+	mutex_unlock(&chip->lock);
+
+	return count;
+}
+
+/* resolution */
+static ssize_t show_resolution(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+
+	return sprintf(buf, "%u\n", chip->adc_bit);
+}
+
+static ssize_t store_resolution(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+	struct i2c_client *client = chip->client;
+	int status;
+	unsigned long lval;
+	unsigned int new_adc_bit;
+
+	if (strict_strtoul(buf, 10, &lval))
+		return -EINVAL;
+	if (!(lval == 4 || lval == 8 || lval == 12 || lval == 16)) {
+		dev_err(dev, "The resolution is not supported\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&chip->lock);
+	status = isl29018_set_resolution(client, lval, &new_adc_bit);
+	if (status < 0) {
+		mutex_unlock(&chip->lock);
+		dev_err(dev, "Error in setting resolution\n");
+		return status;
+	}
+	chip->adc_bit = new_adc_bit;
+	mutex_unlock(&chip->lock);
+
+	return count;
+}
+
+/* proximity scheme */
+static ssize_t show_prox_infrared_supression(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+
+	/* return the "proximity scheme" i.e. if the chip does on chip
+	infrared supression (1 means perform on chip supression) */
+	return sprintf(buf, "%d\n", chip->prox_scheme);
+}
+
+static ssize_t store_prox_infrared_supression(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+	unsigned long lval;
+
+	if (strict_strtoul(buf, 10, &lval))
+		return -EINVAL;
+	if (!(lval == 0UL || lval == 1UL)) {
+		dev_err(dev, "The mode is not supported\n");
+		return -EINVAL;
+	}
+
+	/* get the  "proximity scheme" i.e. if the chip does on chip
+	infrared supression (1 means perform on chip supression) */
+	mutex_lock(&chip->lock);
+	chip->prox_scheme = (int)lval;
+	mutex_unlock(&chip->lock);
+
+	return count;
+}
+
+/* Read lux */
+static ssize_t show_lux(struct device *dev,
+		struct device_attribute *devattr, char *buf)
+{
+	return get_sensor_data(dev, buf, COMMMAND1_OPMODE_ALS_ONCE);
+}
+
+/* Read ir */
+static ssize_t show_ir(struct device *dev,
+		struct device_attribute *devattr, char *buf)
+{
+	return get_sensor_data(dev, buf, COMMMAND1_OPMODE_IR_ONCE);
+}
+
+/* Read nearest ir */
+static ssize_t show_proxim_ir(struct device *dev,
+		struct device_attribute *devattr, char *buf)
+{
+	return get_sensor_data(dev, buf, COMMMAND1_OPMODE_PROX_ONCE);
+}
+
+/* Read name */
+static ssize_t show_name(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct isl29018_chip *chip = indio_dev->dev_data;
+
+	return sprintf(buf, "%s\n", chip->client->name);
+}
+
+static IIO_DEVICE_ATTR(range, S_IRUGO | S_IWUSR, show_range, store_range, 0);
+static IIO_CONST_ATTR(range_available, "1000 4000 16000 64000");
+static IIO_CONST_ATTR(adc_resolution_available, "4 8 12 16");
+static IIO_DEVICE_ATTR(adc_resolution, S_IRUGO | S_IWUSR,
+					show_resolution, store_resolution, 0);
+static IIO_DEVICE_ATTR(proximity_on_chip_ambient_infrared_supression,
+					S_IRUGO | S_IWUSR,
+					show_prox_infrared_supression,
+					store_prox_infrared_supression, 0);
+static IIO_DEVICE_ATTR(illuminance0_input, S_IRUGO, show_lux, NULL, 0);
+static IIO_DEVICE_ATTR(intensity_infrared_raw, S_IRUGO, show_ir, NULL, 0);
+static IIO_DEVICE_ATTR(proximity_raw, S_IRUGO, show_proxim_ir, NULL, 0);
+static IIO_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, 0);
+
+#define ISL29018_DEV_ATTR(name) (&iio_dev_attr_##name.dev_attr.attr)
+#define ISL29018_CONST_ATTR(name) (&iio_const_attr_##name.dev_attr.attr)
+static struct attribute *isl29018_attributes[] = {
+	ISL29018_DEV_ATTR(name),
+	ISL29018_DEV_ATTR(range),
+	ISL29018_CONST_ATTR(range_available),
+	ISL29018_DEV_ATTR(adc_resolution),
+	ISL29018_CONST_ATTR(adc_resolution_available),
+	ISL29018_DEV_ATTR(proximity_on_chip_ambient_infrared_supression),
+	ISL29018_DEV_ATTR(illuminance0_input),
+	ISL29018_DEV_ATTR(intensity_infrared_raw),
+	ISL29018_DEV_ATTR(proximity_raw),
+	NULL
+};
+
+static const struct attribute_group isl29108_group = {
+	.attrs = isl29018_attributes,
+};
+
+static int isl29018_chip_init(struct i2c_client *client)
+{
+	struct isl29018_chip *chip = i2c_get_clientdata(client);
+	int status;
+	int new_adc_bit;
+	unsigned int new_range;
+
+	memset(chip->reg_cache, 0, sizeof(chip->reg_cache));
+
+	/* set defaults */
+	status = isl29018_set_range(client, chip->range, &new_range);
+	if (status < 0) {
+		dev_err(&client->dev, "Init of isl29018 fails\n");
+		return status;
+	}
+
+	status = isl29018_set_resolution(client, chip->adc_bit,
+						&new_adc_bit);
+
+	return 0;
+}
+
+static int __devinit isl29018_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct isl29018_chip *chip;
+	int err;
+
+	chip = kzalloc(sizeof(struct isl29018_chip), GFP_KERNEL);
+	if (!chip) {
+		dev_err(&client->dev, "Memory allocation fails\n");
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	i2c_set_clientdata(client, chip);
+	chip->client = client;
+
+	mutex_init(&chip->lock);
+
+	chip->range = 1000;
+	chip->adc_bit = 16;
+
+	err = isl29018_chip_init(client);
+	if (err)
+		goto exit_free;
+
+	chip->indio_dev = iio_allocate_device();
+	if (!chip->indio_dev) {
+		dev_err(&client->dev, "iio allocation fails\n");
+		goto exit_free;
+	}
+	chip->indio_dev->attrs = &isl29108_group;
+	chip->indio_dev->dev.parent = &client->dev;
+	chip->indio_dev->dev_data = (void *)(chip);
+	chip->indio_dev->driver_module = THIS_MODULE;
+	chip->indio_dev->modes = INDIO_DIRECT_MODE;
+	err = iio_device_register(chip->indio_dev);
+	if (err) {
+		dev_err(&client->dev, "iio registration fails\n");
+		goto exit_iio_free;
+	}
+
+	return 0;
+exit_iio_free:
+	iio_free_device(chip->indio_dev);
+exit_free:
+	kfree(chip);
+exit:
+	return err;
+}
+
+static int __devexit isl29018_remove(struct i2c_client *client)
+{
+	struct isl29018_chip *chip = i2c_get_clientdata(client);
+
+	dev_dbg(&client->dev, "%s()\n", __func__);
+	iio_device_unregister(chip->indio_dev);
+	kfree(chip);
+
+	return 0;
+}
+
+static const struct i2c_device_id isl29018_id[] = {
+	{"isl29018", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, isl29018_id);
+
+static struct i2c_driver isl29018_driver = {
+	.class	= I2C_CLASS_HWMON,
+	.driver	 = {
+			.name = "isl29018",
+			.owner = THIS_MODULE,
+		    },
+	.probe	 = isl29018_probe,
+	.remove	 = __devexit_p(isl29018_remove),
+	.id_table = isl29018_id,
+};
+
+static int __init isl29018_init(void)
+{
+	return i2c_add_driver(&isl29018_driver);
+}
+
+static void __exit isl29018_exit(void)
+{
+	i2c_del_driver(&isl29018_driver);
+}
+
+module_init(isl29018_init);
+module_exit(isl29018_exit);
+
+MODULE_DESCRIPTION("ISL29018 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL");