Re: [PATCH v2] iio: Add Lite-On ltr501 ambient light / proximity sensor driver

[Jonathan Cameron <jic23@kernel.org>]

On 10/01/14 12:22, Peter Meerwald wrote:
> 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
>
> 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
You could have skipped the endian conversions in the buffer code I think and
had the channels as little endian, but given it's not going to be a particularly
fast device, this is fine by me.
>
> Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
> Cc: Lars-Peter Clausen <lars@metafoo.de>
This looks fine to me. Will wait for Lars to come back and declare
himself happy before applying it though!

> ---
>   drivers/iio/light/Kconfig  |  12 ++
>   drivers/iio/light/Makefile |   1 +
>   drivers/iio/light/ltr501.c | 445 +++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 458 insertions(+)
>   create mode 100644 drivers/iio/light/ltr501.c
>
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index c941fbe..6041fa3 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 d8b482e..20fc0dd 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-$(CONFIG_SI114X)		+= si114x.o
>   obj-$(CONFIG_TCS3472)		+= tcs3472.o
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> new file mode 100644
> index 0000000..60d7ada
> --- /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, sizeof(buf), (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");
>