Date:	Thu, 22 Jan 2015 11:48:23 +0100 (CET)
From:	Peter Meerwald <pmeerw@...erw.net>
To:	Daniel Baluta <daniel.baluta@...el.com>
cc:	jic23@...nel.org, ktsai@...ellamicro.com, knaack.h@....de,
	lars@...afoo.de, linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: light: Add support for Capella CM3323 color/light
 sensor

> Minimal implementation providing raw light intensity and illuminance
> readings. For illuminance user can compute lux values using raw readings
> and scale.

minor comments below
the driver does more locking than other implementations; nothing wrong 
with that
 
> This driver also supports CM3323E sensor chip.
> 
> Cc: Kevin Tsai <ktsai@...ellamicro.com>
> Signed-off-by: Daniel Baluta <daniel.baluta@...el.com>
> ---
>  drivers/iio/light/Kconfig  |  10 ++
>  drivers/iio/light/Makefile |   1 +
>  drivers/iio/light/cm3323.c | 345 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 356 insertions(+)
>  create mode 100644 drivers/iio/light/cm3323.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 5bea821..aeaf1c7 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -48,6 +48,16 @@ config CM32181
>  	 To compile this driver as a module, choose M here:
>  	 the module will be called cm32181.
>  
> +config CM3323
> +	depends on I2C
> +	tristate "Capella CM3323 color/ambient light sensor"
> +	help
> +	 Say Y here if you want to build a driver for Capela CM3323
> +	 color sensor. This driver also supports CM3323E sensor.
> +
> +	 To compile this driver as a module, choose M here: the module will
> +	 be called cm3323.
> +
>  config CM36651
>  	depends on I2C
>  	tristate "CM36651 driver"
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index 47877a3..0815b38 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
>  obj-$(CONFIG_AL3320A)		+= al3320a.o
>  obj-$(CONFIG_APDS9300)		+= apds9300.o
>  obj-$(CONFIG_CM32181)		+= cm32181.o
> +obj-$(CONFIG_CM3323)		+= cm3323.o
>  obj-$(CONFIG_CM36651)		+= cm36651.o
>  obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
>  obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
> diff --git a/drivers/iio/light/cm3323.c b/drivers/iio/light/cm3323.c
> new file mode 100644
> index 0000000..5e9b32d
> --- /dev/null
> +++ b/drivers/iio/light/cm3323.c
> @@ -0,0 +1,345 @@
> +/*
> + * CM3323/CM3323E - Capella Color/Ambient Light Sensor
> + *
> + * Copyright (c) 2015, Intel Corporation.
> + *
> + * 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 CM3323/CM3323E (7-bit I2C slave address 0x10)
> + *
> + * TODO: calibscale to correct the lens factor
> + */
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/mutex.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define CM3323_DRV_NAME "cm3323"
> +
> +#define CM3323_CMD_CONF		0x00
> +#define CM3323_CMD_RED_DATA	0x08
> +#define CM3323_CMD_GREEN_DATA	0x09
> +#define CM3323_CMD_BLUE_DATA	0x0A
> +#define CM3323_CMD_CLEAR_DATA	0x0B
> +
> +#define CM3323_CONF_SD_BIT	BIT(0) /* sensor disable */
> +#define CM3323_CONF_AF_BIT	BIT(1) /* auto/manual force mode */
> +#define CM3323_CONF_IT_MASK	(BIT(4) | BIT(5) | BIT(6))
> +#define CM3323_CONF_IT_SHIFT	4
> +
> +#define CM3323_INT_TIME_AVAILABLE "0.04 0.08 0.16 0.32 0.64 1.28"
> +#define CM3323_SCALE_AVAILABLE "0.18 0.09 0.045 0.0225 0.01125 0.005625"
> +
> +static const struct {
> +	int val;
> +	int val2;
> +} cm3323_int_time[] = {
> +	{0, 40000},  /* 40 ms */
> +	{0, 80000},  /* 80 ms */
> +	{0, 160000}, /* 160 ms */
> +	{0, 320000}, /* 320 ms */
> +	{0, 640000}, /* 640 ms */
> +	{1, 280000}, /* 1280 ms */
> +};
> +
> +/* scale depends on integration time */
> +static int cm3323_uscale[] = {
> +	180000, /* 40 ms */
> +	 90000, /* 80 ms */
> +	 45000, /* 160 ms */
> +	 22500, /* 320 ms */
> +	 11250, /* 640 ms */
> +	 5625,  /* 1280 ms */
> +};
> +
> +struct cm3323_data {
> +	struct i2c_client *client;
> +	u16 reg_conf;
> +	struct mutex mutex;
> +};
> +
> +#define CM3323_COLOR_CHANNEL(_color, _addr) {\

perhaps a space between { and \ (here and below)

> +	.type = IIO_INTENSITY, \
> +	.modified = 1, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> +	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
> +	.channel2 = IIO_MOD_LIGHT_##_color, \
> +	.address = _addr, \
> +}
> +
> +/*
> + * CM3323's GREEN channel is used for reading illuminance
> + */
> +#define CM3323_LIGHT_CHANNEL(_addr) {\
> +	.type = IIO_LIGHT, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			      BIT(IIO_CHAN_INFO_SCALE), \
> +	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
> +	.address = _addr, \
> +}
> +
> +static const struct iio_chan_spec cm3323_channels[] = {
> +	CM3323_COLOR_CHANNEL(RED, CM3323_CMD_RED_DATA),
> +	CM3323_COLOR_CHANNEL(GREEN, CM3323_CMD_GREEN_DATA),
> +	CM3323_COLOR_CHANNEL(BLUE, CM3323_CMD_BLUE_DATA),
> +	CM3323_COLOR_CHANNEL(CLEAR, CM3323_CMD_CLEAR_DATA),
> +	CM3323_LIGHT_CHANNEL(CM3323_CMD_GREEN_DATA),
> +};
> +
> +static IIO_CONST_ATTR(in_illuminance_scale_available, CM3323_SCALE_AVAILABLE);
> +static IIO_CONST_ATTR_INT_TIME_AVAIL(CM3323_INT_TIME_AVAILABLE);
> +
> +static struct attribute *cm3323_attributes[] = {
> +	&iio_const_attr_integration_time_available.dev_attr.attr,
> +	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group cm3323_attribute_group = {
> +	.attrs = cm3323_attributes,
> +};
> +
> +static int cm3323_init(struct iio_dev *indio_dev)
> +{
> +	int ret;
> +	struct cm3323_data *data = iio_priv(indio_dev);
> +
> +	ret = i2c_smbus_read_word_data(data->client, CM3323_CMD_CONF);
> +	if (ret < 0) {
> +		dev_err(&data->client->dev, "Error reading reg_conf\n");
> +		return ret;
> +	}
> +
> +	/* enable sensor and set auto force mode */
> +	ret &= ~(CM3323_CONF_SD_BIT | CM3323_CONF_AF_BIT);
> +
> +	ret = i2c_smbus_write_word_data(data->client, CM3323_CMD_CONF, ret);
> +	if (ret < 0) {
> +		dev_err(&data->client->dev, "Error writing reg_conf\n");
> +		return ret;
> +	}
> +
> +	data->reg_conf = ret;
> +
> +	return 0;
> +}
> +
> +static int cm3323_set_it_bits(struct cm3323_data *data, int val, int val2)
> +{
> +	int i, ret;
> +	u16 reg_conf;
> +
> +	for (i = 0; i < ARRAY_SIZE(cm3323_int_time); i++) {
> +		if (val == cm3323_int_time[i].val &&
> +			val2 == cm3323_int_time[i].val2) {
> +			reg_conf = data->reg_conf;
> +			reg_conf |= i << CM3323_CONF_IT_SHIFT;
> +
> +			ret = i2c_smbus_write_word_data(data->client,
> +				 CM3323_CMD_CONF, reg_conf);
> +			if (ret < 0)
> +				return ret;
> +
> +			data->reg_conf = reg_conf;
> +			return 0;
> +		}
> +	}
> +	return -EINVAL;
> +}
> +
> +static int cm3323_set_scale(struct cm3323_data *data, int val, int val2)
> +{
> +	int i, ret;
> +	u16 reg_conf;
> +
> +	if (val != 0)
> +		return 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(cm3323_uscale); i++) {
> +		if (val2 == cm3323_uscale[i]) {
> +			reg_conf = data->reg_conf;
> +			reg_conf |= i << CM3323_CONF_IT_SHIFT;
> +
> +			ret = i2c_smbus_write_word_data(data->client,
> +				 CM3323_CMD_CONF, reg_conf);
> +			if (ret < 0)
> +				return ret;
> +
> +			data->reg_conf = reg_conf;
> +			return 0;
> +		}
> +	}
> +	return -EINVAL;
> +}
> +
> +static int cm3323_get_it_bits(struct cm3323_data *data)
> +{
> +	int bits;
> +
> +	bits = (data->reg_conf & CM3323_CONF_IT_MASK) >>
> +		CM3323_CONF_IT_SHIFT;
> +
> +	if (bits >= ARRAY_SIZE(cm3323_int_time))
> +		return -EINVAL;
> +	return bits;
> +}
> +
> +static int cm3323_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, int *val,
> +			    int *val2, long mask)
> +{
> +	int i, ret;
> +	struct cm3323_data *data = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		mutex_lock(&data->mutex);
> +		ret = i2c_smbus_read_word_data(data->client, chan->address);
> +		if (ret < 0) {
> +			mutex_unlock(&data->mutex);
> +			return ret;
> +		}
> +		*val = ret;
> +		mutex_unlock(&data->mutex);
> +
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_INT_TIME:
> +		mutex_lock(&data->mutex);
> +		i = cm3323_get_it_bits(data);
> +		if (i < 0) {
> +			mutex_unlock(&data->mutex);
> +			return -EINVAL;
> +		}
> +
> +		*val = cm3323_int_time[i].val;
> +		*val2 = cm3323_int_time[i].val2;
> +		mutex_unlock(&data->mutex);
> +
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	case IIO_CHAN_INFO_SCALE:
> +		if (chan->type != IIO_LIGHT)
> +			return -EINVAL;
> +
> +		mutex_lock(&data->mutex);
> +		i = cm3323_get_it_bits(data);
> +		if (i < 0) {
> +			mutex_unlock(&data->mutex);
> +			return -EINVAL;
> +		}
> +		*val = 0;
> +		*val2 = cm3323_uscale[i];
> +		mutex_unlock(&data->mutex);
> +
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	}
> +	return -EINVAL;
> +}
> +
> +static int cm3323_write_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, int val,
> +			    int val2, long mask)
> +{
> +	struct cm3323_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_INT_TIME:
> +		mutex_lock(&data->mutex);
> +		ret = cm3323_set_it_bits(data, val, val2);
> +		mutex_unlock(&data->mutex);
> +
> +		return ret;
> +	case IIO_CHAN_INFO_SCALE:
> +		if (chan->type != IIO_LIGHT)
> +			return -EINVAL;
> +		mutex_lock(&data->mutex);
> +		ret = cm3323_set_scale(data, val, val2);
> +		mutex_unlock(&data->mutex);
> +		return ret;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static const struct iio_info cm3323_info = {
> +	.driver_module	= THIS_MODULE,
> +	.read_raw	= cm3323_read_raw,
> +	.write_raw	= cm3323_write_raw,
> +	.attrs		= &cm3323_attribute_group,
> +};
> +
> +static int cm3323_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct cm3323_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->mutex);
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &cm3323_info;
> +	indio_dev->name = CM3323_DRV_NAME;
> +	indio_dev->channels = cm3323_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(cm3323_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = cm3323_init(indio_dev);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "cm3323 chip init failed\n");
> +		return ret;
> +	}
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static int cm3323_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct cm3323_data *data  = iio_priv(indio_dev);
> +	int ret;
> +
> +	mutex_lock(&data->mutex);
> +	/* disable sensor */
> +	ret = i2c_smbus_write_word_data(client, CM3323_CMD_CONF,
> +					CM3323_CONF_SD_BIT);
> +	if (ret < 0)
> +		dev_err(&client->dev, "Error writing reg_conf\n");
> +
> +	mutex_unlock(&data->mutex);
> +	return ret;
> +}
> +
> +static const struct i2c_device_id cm3323_id[] = {
> +	{"cm3323", 0},
> +	{"cm3323e", 0},

no need to have two IDs I think

> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, cm3323_id);
> +
> +static struct i2c_driver cm3323_driver = {
> +	.driver = {
> +		.name = CM3323_DRV_NAME,
> +	},
> +	.probe		= cm3323_probe,
> +	.remove		= cm3323_remove,
> +	.id_table	= cm3323_id,
> +};
> +
> +module_i2c_driver(cm3323_driver);
> +
> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@...el.com>");
> +MODULE_DESCRIPTION("Capella CM3323 Color/Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL v2");
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
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