372 lines
8.9 KiB
C
372 lines
8.9 KiB
C
/*
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* Copyright (C) 2013 Capella Microsystems Inc.
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* Author: Kevin Tsai <ktsai@capellamicro.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2, as published
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* by the Free Software Foundation.
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*/
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/mutex.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/regulator/consumer.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/events.h>
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#include <linux/init.h>
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/* Registers Address */
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#define CM32181_REG_ADDR_CMD 0x00
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#define CM32181_REG_ADDR_ALS 0x04
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#define CM32181_REG_ADDR_STATUS 0x06
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#define CM32181_REG_ADDR_ID 0x07
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/* Number of Configurable Registers */
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#define CM32181_CONF_REG_NUM 0x01
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/* CMD register */
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#define CM32181_CMD_ALS_ENABLE 0x00
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#define CM32181_CMD_ALS_DISABLE 0x01
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#define CM32181_CMD_ALS_INT_EN 0x02
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#define CM32181_CMD_ALS_IT_SHIFT 6
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#define CM32181_CMD_ALS_IT_MASK (0x0F << CM32181_CMD_ALS_IT_SHIFT)
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#define CM32181_CMD_ALS_IT_DEFAULT (0x00 << CM32181_CMD_ALS_IT_SHIFT)
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#define CM32181_CMD_ALS_SM_SHIFT 11
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#define CM32181_CMD_ALS_SM_MASK (0x03 << CM32181_CMD_ALS_SM_SHIFT)
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#define CM32181_CMD_ALS_SM_DEFAULT (0x01 << CM32181_CMD_ALS_SM_SHIFT)
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#define CM32181_MLUX_PER_BIT 5 /* ALS_SM=01 IT=800ms */
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#define CM32181_MLUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */
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#define CM32181_CALIBSCALE_DEFAULT 1000
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#define CM32181_CALIBSCALE_RESOLUTION 1000
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#define MLUX_PER_LUX 1000
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static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
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CM32181_REG_ADDR_CMD,
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};
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static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
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static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
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800000};
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struct cm32181_chip {
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struct i2c_client *client;
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struct mutex lock;
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u16 conf_regs[CM32181_CONF_REG_NUM];
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int calibscale;
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};
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/**
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* cm32181_reg_init() - Initialize CM32181 registers
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* @cm32181: pointer of struct cm32181.
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*
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* Initialize CM32181 ambient light sensor register to default values.
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*
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* Return: 0 for success; otherwise for error code.
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*/
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static int cm32181_reg_init(struct cm32181_chip *cm32181)
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{
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struct i2c_client *client = cm32181->client;
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int i;
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s32 ret;
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ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
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if (ret < 0)
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return ret;
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/* check device ID */
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if ((ret & 0xFF) != 0x81)
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return -ENODEV;
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/* Default Values */
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cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |
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CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
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cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
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/* Initialize registers*/
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for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
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ret = i2c_smbus_write_word_data(client, cm32181_reg[i],
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cm32181->conf_regs[i]);
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if (ret < 0)
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return ret;
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}
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return 0;
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}
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/**
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* cm32181_read_als_it() - Get sensor integration time (ms)
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* @cm32181: pointer of struct cm32181
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* @val2: pointer of int to load the als_it value.
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*
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* Report the current integartion time by millisecond.
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*
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* Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
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*/
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static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2)
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{
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u16 als_it;
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int i;
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als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
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als_it &= CM32181_CMD_ALS_IT_MASK;
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als_it >>= CM32181_CMD_ALS_IT_SHIFT;
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for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
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if (als_it == als_it_bits[i]) {
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*val2 = als_it_value[i];
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return IIO_VAL_INT_PLUS_MICRO;
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}
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}
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return -EINVAL;
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}
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/**
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* cm32181_write_als_it() - Write sensor integration time
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* @cm32181: pointer of struct cm32181.
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* @val: integration time by millisecond.
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*
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* Convert integration time (ms) to sensor value.
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*
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* Return: i2c_smbus_write_word_data command return value.
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*/
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static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
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{
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struct i2c_client *client = cm32181->client;
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u16 als_it;
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int ret, i, n;
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n = ARRAY_SIZE(als_it_value);
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for (i = 0; i < n; i++)
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if (val <= als_it_value[i])
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break;
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if (i >= n)
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i = n - 1;
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als_it = als_it_bits[i];
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als_it <<= CM32181_CMD_ALS_IT_SHIFT;
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mutex_lock(&cm32181->lock);
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cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
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~CM32181_CMD_ALS_IT_MASK;
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cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
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als_it;
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ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
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cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
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mutex_unlock(&cm32181->lock);
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return ret;
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}
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/**
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* cm32181_get_lux() - report current lux value
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* @cm32181: pointer of struct cm32181.
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*
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* Convert sensor raw data to lux. It depends on integration
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* time and calibscale variable.
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*
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* Return: Positive value is lux, otherwise is error code.
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*/
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static int cm32181_get_lux(struct cm32181_chip *cm32181)
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{
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struct i2c_client *client = cm32181->client;
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int ret;
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int als_it;
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unsigned long lux;
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ret = cm32181_read_als_it(cm32181, &als_it);
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if (ret < 0)
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return -EINVAL;
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lux = CM32181_MLUX_PER_BIT;
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lux *= CM32181_MLUX_PER_BIT_BASE_IT;
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lux /= als_it;
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ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
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if (ret < 0)
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return ret;
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lux *= ret;
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lux *= cm32181->calibscale;
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lux /= CM32181_CALIBSCALE_RESOLUTION;
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lux /= MLUX_PER_LUX;
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if (lux > 0xFFFF)
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lux = 0xFFFF;
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return lux;
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}
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static int cm32181_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct cm32181_chip *cm32181 = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_PROCESSED:
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ret = cm32181_get_lux(cm32181);
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if (ret < 0)
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return ret;
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*val = ret;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_CALIBSCALE:
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*val = cm32181->calibscale;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_INT_TIME:
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*val = 0;
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ret = cm32181_read_als_it(cm32181, val2);
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return ret;
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}
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return -EINVAL;
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}
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static int cm32181_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int val, int val2, long mask)
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{
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struct cm32181_chip *cm32181 = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_CALIBSCALE:
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cm32181->calibscale = val;
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return val;
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case IIO_CHAN_INFO_INT_TIME:
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ret = cm32181_write_als_it(cm32181, val2);
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return ret;
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}
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return -EINVAL;
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}
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/**
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* cm32181_get_it_available() - Get available ALS IT value
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* @dev: pointer of struct device.
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* @attr: pointer of struct device_attribute.
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* @buf: pointer of return string buffer.
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*
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* Display the available integration time values by millisecond.
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*
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* Return: string length.
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*/
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static ssize_t cm32181_get_it_available(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int i, n, len;
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n = ARRAY_SIZE(als_it_value);
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for (i = 0, len = 0; i < n; i++)
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len += sprintf(buf + len, "0.%06u ", als_it_value[i]);
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return len + sprintf(buf + len, "\n");
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}
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static const struct iio_chan_spec cm32181_channels[] = {
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{
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.type = IIO_LIGHT,
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.info_mask_separate =
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BIT(IIO_CHAN_INFO_PROCESSED) |
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BIT(IIO_CHAN_INFO_CALIBSCALE) |
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BIT(IIO_CHAN_INFO_INT_TIME),
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}
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};
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static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
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S_IRUGO, cm32181_get_it_available, NULL, 0);
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static struct attribute *cm32181_attributes[] = {
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&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group cm32181_attribute_group = {
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.attrs = cm32181_attributes
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};
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static const struct iio_info cm32181_info = {
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.driver_module = THIS_MODULE,
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.read_raw = &cm32181_read_raw,
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.write_raw = &cm32181_write_raw,
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.attrs = &cm32181_attribute_group,
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};
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static int cm32181_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct cm32181_chip *cm32181;
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struct iio_dev *indio_dev;
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int ret;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
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if (!indio_dev) {
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dev_err(&client->dev, "devm_iio_device_alloc failed\n");
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return -ENOMEM;
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}
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cm32181 = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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cm32181->client = client;
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mutex_init(&cm32181->lock);
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indio_dev->dev.parent = &client->dev;
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indio_dev->channels = cm32181_channels;
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indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
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indio_dev->info = &cm32181_info;
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indio_dev->name = id->name;
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indio_dev->modes = INDIO_DIRECT_MODE;
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ret = cm32181_reg_init(cm32181);
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if (ret) {
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dev_err(&client->dev,
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"%s: register init failed\n",
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__func__);
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return ret;
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}
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ret = devm_iio_device_register(&client->dev, indio_dev);
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if (ret) {
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dev_err(&client->dev,
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"%s: regist device failed\n",
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__func__);
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return ret;
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}
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return 0;
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}
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static const struct i2c_device_id cm32181_id[] = {
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{ "cm32181", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, cm32181_id);
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static const struct of_device_id cm32181_of_match[] = {
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{ .compatible = "capella,cm32181" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, cm32181_of_match);
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static struct i2c_driver cm32181_driver = {
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.driver = {
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.name = "cm32181",
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.of_match_table = of_match_ptr(cm32181_of_match),
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},
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.id_table = cm32181_id,
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.probe = cm32181_probe,
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};
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module_i2c_driver(cm32181_driver);
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MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
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MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
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MODULE_LICENSE("GPL");
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