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Release 4.7 drivers/iio/light/cm32181.c

/*
 * 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; }

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/** * cm32181_read_als_it() - Get sensor integration time (ms) * @cm32181: pointer of struct cm32181 * @val2: pointer of int to load the als_it value. * * Report the current integartion time by millisecond. * * Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL. */
static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2) { 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]) { *val2 = als_it_value[i]; return IIO_VAL_INT_PLUS_MICRO; } } return -EINVAL; }

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/** * 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; }

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/** * cm32181_get_lux() - report current lux value * @cm32181: pointer of struct cm32181. * * Convert sensor raw data to lux. It depends on integration * time and calibscale 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; }

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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: *val = 0; ret = cm32181_read_als_it(cm32181, val2); return ret; } return -EINVAL; }

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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, val2); return ret; } return -EINVAL; }

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/** * 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, "0.%06u ", als_it_value[i]); return len + sprintf(buf + len, "\n"); }

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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 = devm_iio_device_register(&client->dev, indio_dev); if (ret) { dev_err(&client->dev, "%s: regist device failed\n", __func__); return ret; } return 0; }

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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" }, { } }; MODULE_DEVICE_TABLE(of, cm32181_of_match); static struct i2c_driver cm32181_driver = { .driver = { .name = "cm32181", .of_match_table = of_match_ptr(cm32181_of_match), }, .id_table = cm32181_id, .probe = cm32181_probe, }; module_i2c_driver(cm32181_driver); MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>"); MODULE_DESCRIPTION("CM32181 ambient light sensor driver"); MODULE_LICENSE("GPL");

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