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>

3 files changed, 229 insertions, 0 deletions

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index db5618e7d90b..f3ea90d735b8 100644
--- a/drivers/iio/light/Kconfig
+++ b/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
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index c1c23a024cd2..06fa4d3f33ec 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_SENSORS_LM3533)    += lm3533-als.o
+obj-$(CONFIG_VCNL4000)          += vcnl4000.o
diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
new file mode 100644
index 000000000000..e49cb9784a6f
--- /dev/null
+++ b/drivers/iio/light/vcnl4000.c
@@ -0,0 +1,217 @@
+/*
+ * 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");