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Commit 971672c0 authored by Kevin Tsai's avatar Kevin Tsai Committed by Jonathan Cameron
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iio: add Capella CM32181 ambient light sensor driver. 



Add Capella Microsystem CM32181 Ambient Light Sensor IIO driver.
This driver will convert raw data to lux value under open-air
condition. Change the calibscale based on the cover material.

Signed-off-by: default avatarKevin Tsai <ktsai@capellamicro.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent a6e8e3a4

Documentation/devicetree/bindings/i2c/trivial-devices.txt

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ adt7461 +/-1C TDM Extended Temp Range I.C 
at,24c08		i2c serial eeprom  (24cxx)

atmel,24c02		i2c serial eeprom  (24cxx)

atmel,at97sc3204t	i2c trusted platform module (TPM)

capella,cm32181		CM32181: Ambient Light Sensor

catalyst,24c32		i2c serial eeprom

dallas,ds1307		64 x 8, Serial, I2C Real-Time Clock

dallas,ds1338		I2C RTC with 56-Byte NV RAM

drivers/iio/light/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -27,6 +27,17 @@ config APDS9300 
	 To compile this driver as a module, choose M here: the

	 module will be called apds9300.



config CM32181

	depends on I2C

	tristate "CM32181 driver"

	help

	 Say Y here if you use cm32181.

	 This option enables ambient light sensor using

	 Capella cm32181 device driver.



	 To compile this driver as a module, choose M here:

	 the module will be called cm32181.



config CM36651

	depends on I2C

	tristate "CM36651 driver"

drivers/iio/light/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
# When adding new entries keep the list in alphabetical order

obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o

obj-$(CONFIG_APDS9300)		+= apds9300.o

obj-$(CONFIG_CM32181)		+= cm32181.o

obj-$(CONFIG_CM36651)		+= cm36651.o

obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o

obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o

drivers/iio/light/cm32181.c

0 → 100644
+379 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2013 Capella Microsystems Inc.

 * Author: Kevin Tsai <ktsai@capellamicro.com>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2, as published

 * by the Free Software Foundation.

 */



#include <linux/delay.h>

#include <linux/err.h>

#include <linux/i2c.h>

#include <linux/mutex.h>

#include <linux/module.h>

#include <linux/interrupt.h>

#include <linux/regulator/consumer.h>

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/iio/events.h>

#include <linux/init.h>



/* Registers Address */

#define CM32181_REG_ADDR_CMD		0x00

#define CM32181_REG_ADDR_ALS		0x04

#define CM32181_REG_ADDR_STATUS		0x06

#define CM32181_REG_ADDR_ID		0x07



/* Number of Configurable Registers */

#define CM32181_CONF_REG_NUM		0x01



/* CMD register */

#define CM32181_CMD_ALS_ENABLE		0x00

#define CM32181_CMD_ALS_DISABLE		0x01

#define CM32181_CMD_ALS_INT_EN		0x02



#define CM32181_CMD_ALS_IT_SHIFT	6

#define CM32181_CMD_ALS_IT_MASK		(0x0F << CM32181_CMD_ALS_IT_SHIFT)

#define CM32181_CMD_ALS_IT_DEFAULT	(0x00 << CM32181_CMD_ALS_IT_SHIFT)



#define CM32181_CMD_ALS_SM_SHIFT	11

#define CM32181_CMD_ALS_SM_MASK		(0x03 << CM32181_CMD_ALS_SM_SHIFT)

#define CM32181_CMD_ALS_SM_DEFAULT	(0x01 << CM32181_CMD_ALS_SM_SHIFT)



#define CM32181_MLUX_PER_BIT		5	/* ALS_SM=01 IT=800ms */

#define CM32181_MLUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */

#define	CM32181_CALIBSCALE_DEFAULT	1000

#define CM32181_CALIBSCALE_RESOLUTION	1000

#define MLUX_PER_LUX			1000



static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {

	CM32181_REG_ADDR_CMD,

};



static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};

static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,

	800000};



struct cm32181_chip {

	struct i2c_client *client;

	struct mutex lock;

	u16 conf_regs[CM32181_CONF_REG_NUM];

	int calibscale;

};



/**

 * cm32181_reg_init() - Initialize CM32181 registers

 * @cm32181:	pointer of struct cm32181.

 *

 * Initialize CM32181 ambient light sensor register to default values.

 *

 * Return: 0 for success; otherwise for error code.

 */

static int cm32181_reg_init(struct cm32181_chip *cm32181)

{

	struct i2c_client *client = cm32181->client;

	int i;

	s32 ret;



	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);

	if (ret < 0)

		return ret;



	/* check device ID */

	if ((ret & 0xFF) != 0x81)

		return -ENODEV;



	/* Default Values */

	cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |

			CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;

	cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;



	/* Initialize registers*/

	for (i = 0; i < CM32181_CONF_REG_NUM; i++) {

		ret = i2c_smbus_write_word_data(client, cm32181_reg[i],

			cm32181->conf_regs[i]);

		if (ret < 0)

			return ret;

	}



	return 0;

}



/**

 *  cm32181_read_als_it() - Get sensor integration time (ms)

 *  @cm32181:	pointer of struct cm32181

 *  @val:	pointer of int to load the als_it value.

 *

 *  Report the current integartion time by millisecond.

 *

 *  Return: IIO_VAL_INT for success, otherwise -EINVAL.

 */

static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val)

{

	u16 als_it;

	int i;



	als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];

	als_it &= CM32181_CMD_ALS_IT_MASK;

	als_it >>= CM32181_CMD_ALS_IT_SHIFT;

	for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {

		if (als_it == als_it_bits[i]) {

			*val = als_it_value[i];

			return IIO_VAL_INT;

		}

	}



	return -EINVAL;

}



/**

 * cm32181_write_als_it() - Write sensor integration time

 * @cm32181:	pointer of struct cm32181.

 * @val:	integration time by millisecond.

 *

 * Convert integration time (ms) to sensor value.

 *

 * Return: i2c_smbus_write_word_data command return value.

 */

static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)

{

	struct i2c_client *client = cm32181->client;

	u16 als_it;

	int ret, i, n;



	n = ARRAY_SIZE(als_it_value);

	for (i = 0; i < n; i++)

		if (val <= als_it_value[i])

			break;

	if (i >= n)

		i = n - 1;



	als_it = als_it_bits[i];

	als_it <<= CM32181_CMD_ALS_IT_SHIFT;



	mutex_lock(&cm32181->lock);

	cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=

		~CM32181_CMD_ALS_IT_MASK;

	cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=

		als_it;

	ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,

			cm32181->conf_regs[CM32181_REG_ADDR_CMD]);

	mutex_unlock(&cm32181->lock);



	return ret;

}



/**

 * cm32181_get_lux() - report current lux value

 * @cm32181:	pointer of struct cm32181.

 *

 * Convert sensor raw data to lux.  It depends on integration

 * time and claibscale variable.

 *

 * Return: Positive value is lux, otherwise is error code.

 */

static int cm32181_get_lux(struct cm32181_chip *cm32181)

{

	struct i2c_client *client = cm32181->client;

	int ret;

	int als_it;

	unsigned long lux;



	ret = cm32181_read_als_it(cm32181, &als_it);

	if (ret < 0)

		return -EINVAL;



	lux = CM32181_MLUX_PER_BIT;

	lux *= CM32181_MLUX_PER_BIT_BASE_IT;

	lux /= als_it;



	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);

	if (ret < 0)

		return ret;



	lux *= ret;

	lux *= cm32181->calibscale;

	lux /= CM32181_CALIBSCALE_RESOLUTION;

	lux /= MLUX_PER_LUX;



	if (lux > 0xFFFF)

		lux = 0xFFFF;



	return lux;

}



static int cm32181_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan,

			    int *val, int *val2, long mask)

{

	struct cm32181_chip *cm32181 = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_PROCESSED:

		ret = cm32181_get_lux(cm32181);

		if (ret < 0)

			return ret;

		*val = ret;

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_CALIBSCALE:

		*val = cm32181->calibscale;

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_INT_TIME:

		ret = cm32181_read_als_it(cm32181, val);

		return ret;

	}



	return -EINVAL;

}



static int cm32181_write_raw(struct iio_dev *indio_dev,

			     struct iio_chan_spec const *chan,

			     int val, int val2, long mask)

{

	struct cm32181_chip *cm32181 = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_CALIBSCALE:

		cm32181->calibscale = val;

		return val;

	case IIO_CHAN_INFO_INT_TIME:

		ret = cm32181_write_als_it(cm32181, val);

		return ret;

	}



	return -EINVAL;

}



/**

 * cm32181_get_it_available() - Get available ALS IT value

 * @dev:	pointer of struct device.

 * @attr:	pointer of struct device_attribute.

 * @buf:	pointer of return string buffer.

 *

 * Display the available integration time values by millisecond.

 *

 * Return: string length.

 */

static ssize_t cm32181_get_it_available(struct device *dev,

			struct device_attribute *attr, char *buf)

{

	int i, n, len;



	n = ARRAY_SIZE(als_it_value);

	for (i = 0, len = 0; i < n; i++)

		len += sprintf(buf + len, "%d ", als_it_value[i]);

	return len + sprintf(buf + len, "\n");

}



static const struct iio_chan_spec cm32181_channels[] = {

	{

		.type = IIO_LIGHT,

		.info_mask_separate =

			BIT(IIO_CHAN_INFO_PROCESSED) |

			BIT(IIO_CHAN_INFO_CALIBSCALE) |

			BIT(IIO_CHAN_INFO_INT_TIME),

	}

};



static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,

			S_IRUGO, cm32181_get_it_available, NULL, 0);



static struct attribute *cm32181_attributes[] = {

	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,

	NULL,

};



static const struct attribute_group cm32181_attribute_group = {

	.attrs = cm32181_attributes

};



static const struct iio_info cm32181_info = {

	.driver_module		= THIS_MODULE,

	.read_raw		= &cm32181_read_raw,

	.write_raw		= &cm32181_write_raw,

	.attrs			= &cm32181_attribute_group,

};



static int cm32181_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	struct cm32181_chip *cm32181;

	struct iio_dev *indio_dev;

	int ret;



	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));

	if (!indio_dev) {

		dev_err(&client->dev, "devm_iio_device_alloc failed\n");

		return -ENOMEM;

	}



	cm32181 = iio_priv(indio_dev);

	i2c_set_clientdata(client, indio_dev);

	cm32181->client = client;



	mutex_init(&cm32181->lock);

	indio_dev->dev.parent = &client->dev;

	indio_dev->channels = cm32181_channels;

	indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);

	indio_dev->info = &cm32181_info;

	indio_dev->name = id->name;

	indio_dev->modes = INDIO_DIRECT_MODE;



	ret = cm32181_reg_init(cm32181);

	if (ret) {

		dev_err(&client->dev,

			"%s: register init failed\n",

			__func__);

		return ret;

	}



	ret = iio_device_register(indio_dev);

	if (ret) {

		dev_err(&client->dev,

			"%s: regist device failed\n",

			__func__);

		return ret;

	}



	return 0;

}



static int cm32181_remove(struct i2c_client *client)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(client);



	iio_device_unregister(indio_dev);

	return 0;

}



static const struct i2c_device_id cm32181_id[] = {

	{ "cm32181", 0 },

	{ }

};



MODULE_DEVICE_TABLE(i2c, cm32181_id);



static const struct of_device_id cm32181_of_match[] = {

	{ .compatible = "capella,cm32181" },

	{ }

};



static struct i2c_driver cm32181_driver = {

	.driver = {

		.name	= "cm32181",

		.of_match_table = of_match_ptr(cm32181_of_match),

		.owner	= THIS_MODULE,

	},

	.id_table       = cm32181_id,

	.probe		= cm32181_probe,

	.remove		= cm32181_remove,

};



module_i2c_driver(cm32181_driver);



MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");

MODULE_DESCRIPTION("CM32181 ambient light sensor driver");

MODULE_LICENSE("GPL");