iio: add vcnl4000 combined ALS and proximity sensor

minimal driver, no IR current control and proximity/event
handling yet

v5:
* checkpatch warnings
* increase msleep() to 20 ms when waiting for data ready as
  measurement/conversion can take up to 100 ms, 1 ms is too short

v4 (address comments by Jonathan Cameron)
* remove SENSORS_ prefix in Kconfig
* change from IIO_INTENSITY to IIO_LIGHT
* move from staging

v3 (address comments by Shubhrajyoti Datta)
* cleanup Kconfig entry
* call I2C read/write functions directly

v2 (address comments by Lars-Peter Clausen and Jonathan Cameron)
* unify code for reading PS and AL data into
  parameterized _measure() function
* limit wait for data to become ready within 20 tries
* drop IIO_LIGHT channel, add SCALE to IIO_INTENSITY
* drop extra string arguments used for logging purpose only
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/iio/light/Kconfig

@@ -19,4 +19,15 @@ config SENSORS_LM3533
 	  light zone through sysfs. A threshold event can be generated on zone
 	  changes. The ALS-control output values can be set per zone for the
 	  three current output channels.
+
+config VCNL4000
+	tristate "VCNL4000 combined ALS and proximity sensor"
+	depends on I2C
+	help
+	 Say Y here if you want to build a driver for the Vishay VCNL4000
+	 combined ambient light and proximity sensor.
+
+	 To compile this driver as a module, choose M here: the
+	 module will be called vcnl4000.
+
 endmenu

drivers/iio/light/Makefile

@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
+obj-$(CONFIG_VCNL4000)		+= vcnl4000.o

drivers/iio/light/vcnl4000.c

+/*
+ * vcnl4000.c - Support for Vishay VCNL4000 combined ambient light and
+ * proximity sensor
+ *
+ * Copyright 2012 Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * IIO driver for VCNL4000 (7-bit I2C slave address 0x13)
+ *
+ * TODO:
+ *   allow to adjust IR current
+ *   proximity threshold and event handling
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define VCNL4000_DRV_NAME "vcnl4000"
+
+#define VCNL4000_COMMAND	0x80 /* Command register */
+#define VCNL4000_PROD_REV	0x81 /* Product ID and Revision ID */
+#define VCNL4000_LED_CURRENT	0x83 /* IR LED current for proximity mode */
+#define VCNL4000_AL_PARAM	0x84 /* Ambient light parameter register */
+#define VCNL4000_AL_RESULT_HI	0x85 /* Ambient light result register, MSB */
+#define VCNL4000_AL_RESULT_LO	0x86 /* Ambient light result register, LSB */
+#define VCNL4000_PS_RESULT_HI	0x87 /* Proximity result register, MSB */
+#define VCNL4000_PS_RESULT_LO	0x88 /* Proximity result register, LSB */
+#define VCNL4000_PS_MEAS_FREQ	0x89 /* Proximity test signal frequency */
+#define VCNL4000_PS_MOD_ADJ	0x8a /* Proximity modulator timing adjustment */
+
+/* Bit masks for COMMAND register */
+#define VCNL4000_AL_RDY		0x40 /* ALS data ready? */
+#define VCNL4000_PS_RDY		0x20 /* proximity data ready? */
+#define VCNL4000_AL_OD		0x10 /* start on-demand ALS measurement */
+#define VCNL4000_PS_OD		0x08 /* start on-demand proximity measurement */
+
+struct vcnl4000_data {
+	struct i2c_client *client;
+};
+
+static const struct i2c_device_id vcnl4000_id[] = {
+	{ "vcnl4000", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, vcnl4000_id);
+
+static int vcnl4000_measure(struct vcnl4000_data *data, u8 req_mask,
+				u8 rdy_mask, u8 data_reg, int *val)
+{
+	int tries = 20;
+	u16 buf;
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, VCNL4000_COMMAND,
+					req_mask);
+	if (ret < 0)
+		return ret;
+
+	/* wait for data to become ready */
+	while (tries--) {
+		ret = i2c_smbus_read_byte_data(data->client, VCNL4000_COMMAND);
+		if (ret < 0)
+			return ret;
+		if (ret & rdy_mask)
+			break;
+		msleep(20); /* measurement takes up to 100 ms */
+	}
+
+	if (tries < 0) {
+		dev_err(&data->client->dev,
+			"vcnl4000_measure() failed, data not ready\n");
+		return -EIO;
+	}
+
+	ret = i2c_smbus_read_i2c_block_data(data->client,
+		data_reg, sizeof(buf), (u8 *) &buf);
+	if (ret < 0)
+		return ret;
+
+	*val = be16_to_cpu(buf);
+
+	return 0;
+}
+
+static const struct iio_chan_spec vcnl4000_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
+			IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
+	}, {
+		.type = IIO_PROXIMITY,
+		.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
+	}
+};
+
+static int vcnl4000_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	int ret = -EINVAL;
+	struct vcnl4000_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_LIGHT:
+			ret = vcnl4000_measure(data,
+				VCNL4000_AL_OD, VCNL4000_AL_RDY,
+				VCNL4000_AL_RESULT_HI, val);
+			if (ret < 0)
+				return ret;
+			ret = IIO_VAL_INT;
+			break;
+		case IIO_PROXIMITY:
+			ret = vcnl4000_measure(data,
+				VCNL4000_PS_OD, VCNL4000_PS_RDY,
+				VCNL4000_PS_RESULT_HI, val);
+			if (ret < 0)
+				return ret;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type == IIO_LIGHT) {
+			*val = 0;
+			*val2 = 250000;
+			ret = IIO_VAL_INT_PLUS_MICRO;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static const struct iio_info vcnl4000_info = {
+	.read_raw = vcnl4000_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int __devinit vcnl4000_probe(struct i2c_client *client,
+					const struct i2c_device_id *id)
+{
+	struct vcnl4000_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = iio_device_alloc(sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	ret = i2c_smbus_read_byte_data(data->client, VCNL4000_PROD_REV);
+	if (ret < 0)
+		goto error_free_dev;
+
+	dev_info(&client->dev, "VCNL4000 Ambient light/proximity sensor, Prod %02x, Rev: %02x\n",
+		ret >> 4, ret & 0xf);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &vcnl4000_info;
+	indio_dev->channels = vcnl4000_channels;
+	indio_dev->num_channels = ARRAY_SIZE(vcnl4000_channels);
+	indio_dev->name = VCNL4000_DRV_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0)
+		goto error_free_dev;
+
+	return 0;
+
+error_free_dev:
+	iio_device_free(indio_dev);
+	return ret;
+}
+
+static int __devexit vcnl4000_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+static struct i2c_driver vcnl4000_driver = {
+	.driver = {
+		.name   = VCNL4000_DRV_NAME,
+		.owner  = THIS_MODULE,
+	},
+	.probe  = vcnl4000_probe,
+	.remove = __devexit_p(vcnl4000_remove),
+	.id_table = vcnl4000_id,
+};
+
+module_i2c_driver(vcnl4000_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("Vishay VCNL4000 proximity/ambient light sensor driver");
+MODULE_LICENSE("GPL");