iio: Add Lite-On ltr501 ambient light / proximity sensor driver

combined ambient light (two channels) and proximity sensor with I2C
interface; the ALS channels are visible+IR and IR

datasheet is here
http://optoelectronics.liteon.com/upload/download/DS86-2012-0006/P_100_LTR-501ALS-01_PrelimDS_ver1.1.pdf

v3:
* fix use of sizeof in _read_als()
v2: (thanks to Lars-Peter Clausen)
* cannot use devm_iio_device_register() due to cleanup order in _remove()
* mutex around data wait/read
* turn info message in _probe() into check for part number
* change copyright year to 2014

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 458 insertions, 0 deletions

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index d12b2a0dbfbc..3a7a5d9f03a3 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -90,6 +90,18 @@ config SENSORS_LM3533
 	  changes. The ALS-control output values can be set per zone for the
 	  three current output channels.
 
+config LTR501
+	tristate "LTR-501ALS-01 light sensor"
+	depends on I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	 If you say yes here you get support for the Lite-On LTR-501ALS-01
+	 ambient light and proximity sensor.
+
+	 This driver can also be built as a module.  If so, the module
+         will be called ltr501.
+
 config TCS3472
 	tristate "TAOS TCS3472 color light-to-digital converter"
 	depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 60e35ac07ff0..924530597f83 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_CM36651)		+= cm36651.o
 obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
+obj-$(CONFIG_LTR501)		+= ltr501.o
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o
 obj-$(CONFIG_TCS3472)		+= tcs3472.o
 obj-$(CONFIG_TSL4531)		+= tsl4531.o
diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
new file mode 100644
index 000000000000..62b7072af4de
--- /dev/null
+++ b/drivers/iio/light/ltr501.c
@@ -0,0 +1,445 @@
+/*
+ * ltr501.c - Support for Lite-On LTR501 ambient light and proximity sensor
+ *
+ * Copyright 2014 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.
+ *
+ * 7-bit I2C slave address 0x23
+ *
+ * TODO: interrupt, threshold, measurement rate, IR LED characteristics
+ */
+
+#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>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define LTR501_DRV_NAME "ltr501"
+
+#define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
+#define LTR501_PS_CONTR 0x81 /* PS operation mode */
+#define LTR501_PART_ID 0x86
+#define LTR501_MANUFAC_ID 0x87
+#define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */
+#define LTR501_ALS_DATA0 0x8a /* 16-bit, little endian */
+#define LTR501_ALS_PS_STATUS 0x8c
+#define LTR501_PS_DATA 0x8d /* 16-bit, little endian */
+
+#define LTR501_ALS_CONTR_SW_RESET BIT(2)
+#define LTR501_CONTR_PS_GAIN_MASK (BIT(3) | BIT(2))
+#define LTR501_CONTR_PS_GAIN_SHIFT 2
+#define LTR501_CONTR_ALS_GAIN_MASK BIT(3)
+#define LTR501_CONTR_ACTIVE BIT(1)
+
+#define LTR501_STATUS_ALS_RDY BIT(2)
+#define LTR501_STATUS_PS_RDY BIT(0)
+
+#define LTR501_PS_DATA_MASK 0x7ff
+
+struct ltr501_data {
+	struct i2c_client *client;
+	struct mutex lock_als, lock_ps;
+	u8 als_contr, ps_contr;
+};
+
+static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
+{
+	int tries = 100;
+	int ret;
+
+	while (tries--) {
+		ret = i2c_smbus_read_byte_data(data->client,
+			LTR501_ALS_PS_STATUS);
+		if (ret < 0)
+			return ret;
+		if ((ret & drdy_mask) == drdy_mask)
+			return 0;
+		msleep(25);
+	}
+
+	dev_err(&data->client->dev, "ltr501_drdy() failed, data not ready\n");
+	return -EIO;
+}
+
+static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
+{
+	int ret = ltr501_drdy(data, LTR501_STATUS_ALS_RDY);
+	if (ret < 0)
+		return ret;
+	/* always read both ALS channels in given order */
+	return i2c_smbus_read_i2c_block_data(data->client,
+		LTR501_ALS_DATA1, 2 * sizeof(__le16), (u8 *) buf);
+}
+
+static int ltr501_read_ps(struct ltr501_data *data)
+{
+	int ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
+	if (ret < 0)
+		return ret;
+	return i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
+}
+
+#define LTR501_INTENSITY_CHANNEL(_idx, _addr, _mod, _shared) { \
+	.type = IIO_INTENSITY, \
+	.modified = 1, \
+	.address = (_addr), \
+	.channel2 = (_mod), \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	.info_mask_shared_by_type = (_shared), \
+	.scan_index = (_idx), \
+	.scan_type = { \
+		.sign = 'u', \
+		.realbits = 16, \
+		.storagebits = 16, \
+		.endianness = IIO_CPU, \
+	} \
+}
+
+static const struct iio_chan_spec ltr501_channels[] = {
+	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
+	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
+		BIT(IIO_CHAN_INFO_SCALE)),
+	{
+		.type = IIO_PROXIMITY,
+		.address = LTR501_PS_DATA,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_SCALE),
+		.scan_index = 2,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 11,
+			.storagebits = 16,
+			.endianness = IIO_CPU,
+		},
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static const int ltr501_ps_gain[4][2] = {
+	{1, 0}, {0, 250000}, {0, 125000}, {0, 62500}
+};
+
+static int ltr501_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct ltr501_data *data = iio_priv(indio_dev);
+	__le16 buf[2];
+	int ret, i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (iio_buffer_enabled(indio_dev))
+			return -EBUSY;
+
+		switch (chan->type) {
+		case IIO_INTENSITY:
+			mutex_lock(&data->lock_als);
+			ret = ltr501_read_als(data, buf);
+			mutex_unlock(&data->lock_als);
+			if (ret < 0)
+				return ret;
+			*val = le16_to_cpu(chan->address == LTR501_ALS_DATA1 ?
+				buf[0] : buf[1]);
+			return IIO_VAL_INT;
+		case IIO_PROXIMITY:
+			mutex_lock(&data->lock_ps);
+			ret = ltr501_read_ps(data);
+			mutex_unlock(&data->lock_ps);
+			if (ret < 0)
+				return ret;
+			*val = ret & LTR501_PS_DATA_MASK;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_INTENSITY:
+			if (data->als_contr & LTR501_CONTR_ALS_GAIN_MASK) {
+				*val = 0;
+				*val2 = 5000;
+				return IIO_VAL_INT_PLUS_MICRO;
+			} else {
+				*val = 1;
+				*val2 = 0;
+				return IIO_VAL_INT;
+			}
+		case IIO_PROXIMITY:
+			i = (data->ps_contr & LTR501_CONTR_PS_GAIN_MASK) >>
+				LTR501_CONTR_PS_GAIN_SHIFT;
+			*val = ltr501_ps_gain[i][0];
+			*val2 = ltr501_ps_gain[i][1];
+			return IIO_VAL_INT_PLUS_MICRO;
+		default:
+			return -EINVAL;
+		}
+	}
+	return -EINVAL;
+}
+
+static int ltr501_get_ps_gain_index(int val, int val2)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ltr501_ps_gain); i++)
+		if (val == ltr501_ps_gain[i][0] && val2 == ltr501_ps_gain[i][1])
+			return i;
+
+	return -1;
+}
+
+static int ltr501_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val, int val2, long mask)
+{
+	struct ltr501_data *data = iio_priv(indio_dev);
+	int i;
+
+	if (iio_buffer_enabled(indio_dev))
+		return -EBUSY;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_INTENSITY:
+			if (val == 0 && val2 == 5000)
+				data->als_contr |= LTR501_CONTR_ALS_GAIN_MASK;
+			else if (val == 1 && val2 == 0)
+				data->als_contr &= ~LTR501_CONTR_ALS_GAIN_MASK;
+			else
+				return -EINVAL;
+			return i2c_smbus_write_byte_data(data->client,
+				LTR501_ALS_CONTR, data->als_contr);
+		case IIO_PROXIMITY:
+			i = ltr501_get_ps_gain_index(val, val2);
+			if (i < 0)
+				return -EINVAL;
+			data->ps_contr &= ~LTR501_CONTR_PS_GAIN_MASK;
+			data->ps_contr |= i << LTR501_CONTR_PS_GAIN_SHIFT;
+			return i2c_smbus_write_byte_data(data->client,
+				LTR501_PS_CONTR, data->ps_contr);
+		default:
+			return -EINVAL;
+		}
+	}
+	return -EINVAL;
+}
+
+static IIO_CONST_ATTR(in_proximity_scale_available, "1 0.25 0.125 0.0625");
+static IIO_CONST_ATTR(in_intensity_scale_available, "1 0.005");
+
+static struct attribute *ltr501_attributes[] = {
+	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
+	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group ltr501_attribute_group = {
+	.attrs = ltr501_attributes,
+};
+
+static const struct iio_info ltr501_info = {
+	.read_raw = ltr501_read_raw,
+	.write_raw = ltr501_write_raw,
+	.attrs = &ltr501_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static int ltr501_write_contr(struct i2c_client *client, u8 als_val, u8 ps_val)
+{
+	int ret = i2c_smbus_write_byte_data(client, LTR501_ALS_CONTR, als_val);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(client, LTR501_PS_CONTR, ps_val);
+}
+
+static irqreturn_t ltr501_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ltr501_data *data = iio_priv(indio_dev);
+	u16 buf[8];
+	__le16 als_buf[2];
+	u8 mask = 0;
+	int j = 0;
+	int ret;
+
+	memset(buf, 0, sizeof(buf));
+
+	/* figure out which data needs to be ready */
+	if (test_bit(0, indio_dev->active_scan_mask) ||
+		test_bit(1, indio_dev->active_scan_mask))
+		mask |= LTR501_STATUS_ALS_RDY;
+	if (test_bit(2, indio_dev->active_scan_mask))
+		mask |= LTR501_STATUS_PS_RDY;
+
+	ret = ltr501_drdy(data, mask);
+	if (ret < 0)
+		goto done;
+
+	if (mask & LTR501_STATUS_ALS_RDY) {
+		ret = i2c_smbus_read_i2c_block_data(data->client,
+			LTR501_ALS_DATA1, sizeof(als_buf), (u8 *) als_buf);
+		if (ret < 0)
+			return ret;
+		if (test_bit(0, indio_dev->active_scan_mask))
+			buf[j++] = le16_to_cpu(als_buf[1]);
+		if (test_bit(1, indio_dev->active_scan_mask))
+			buf[j++] = le16_to_cpu(als_buf[0]);
+	}
+
+	if (mask & LTR501_STATUS_PS_RDY) {
+		ret = i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
+		if (ret < 0)
+			goto done;
+		buf[j++] = ret & LTR501_PS_DATA_MASK;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, buf,
+		iio_get_time_ns());
+
+done:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int ltr501_init(struct ltr501_data *data)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(data->client, LTR501_ALS_CONTR);
+	if (ret < 0)
+		return ret;
+	data->als_contr = ret | LTR501_CONTR_ACTIVE;
+
+	ret = i2c_smbus_read_byte_data(data->client, LTR501_PS_CONTR);
+	if (ret < 0)
+		return ret;
+	data->ps_contr = ret | LTR501_CONTR_ACTIVE;
+
+	return ltr501_write_contr(data->client, data->als_contr,
+		data->ps_contr);
+}
+
+static int ltr501_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct ltr501_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+	mutex_init(&data->lock_als);
+	mutex_init(&data->lock_ps);
+
+	ret = i2c_smbus_read_byte_data(data->client, LTR501_PART_ID);
+	if (ret < 0)
+		return ret;
+	if ((ret >> 4) != 0x8)
+		return -ENODEV;
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &ltr501_info;
+	indio_dev->channels = ltr501_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ltr501_channels);
+	indio_dev->name = LTR501_DRV_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = ltr501_init(data);
+	if (ret < 0)
+		return ret;
+
+	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+		ltr501_trigger_handler, NULL);
+	if (ret)
+		return ret;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_unreg_buffer;
+
+	return 0;
+
+error_unreg_buffer:
+	iio_triggered_buffer_cleanup(indio_dev);
+	return ret;
+}
+
+static int ltr501_powerdown(struct ltr501_data *data)
+{
+	return ltr501_write_contr(data->client,
+		data->als_contr & ~LTR501_CONTR_ACTIVE,
+		data->ps_contr & ~LTR501_CONTR_ACTIVE);
+}
+
+static int ltr501_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+	ltr501_powerdown(iio_priv(indio_dev));
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int ltr501_suspend(struct device *dev)
+{
+	struct ltr501_data *data = iio_priv(i2c_get_clientdata(
+		to_i2c_client(dev)));
+	return ltr501_powerdown(data);
+}
+
+static int ltr501_resume(struct device *dev)
+{
+	struct ltr501_data *data = iio_priv(i2c_get_clientdata(
+		to_i2c_client(dev)));
+
+	return ltr501_write_contr(data->client, data->als_contr,
+		data->ps_contr);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(ltr501_pm_ops, ltr501_suspend, ltr501_resume);
+
+static const struct i2c_device_id ltr501_id[] = {
+	{ "ltr501", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ltr501_id);
+
+static struct i2c_driver ltr501_driver = {
+	.driver = {
+		.name   = LTR501_DRV_NAME,
+		.pm	= &ltr501_pm_ops,
+		.owner  = THIS_MODULE,
+	},
+	.probe  = ltr501_probe,
+	.remove	= ltr501_remove,
+	.id_table = ltr501_id,
+};
+
+module_i2c_driver(ltr501_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("Lite-On LTR501 ambient light and proximity sensor driver");
+MODULE_LICENSE("GPL");