// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  isl29003.c - Linux kernel module for
 *      Intersil ISL29003 ambient light sensor
 *
 *  See file:Documentation/misc-devices/isl29003.rst
 *
 *  Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
 *
 *  Based on code written by
 *      Rodolfo Giometti <giometti@linux.it>
 *      Eurotech S.p.A. <info@eurotech.it>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/delay.h>

#define ISL29003_DRV_NAME       "isl29003"
#define DRIVER_VERSION          "1.0"

#define ISL29003_REG_COMMAND            0x00
#define ISL29003_ADC_ENABLED            (1 << 7)
#define ISL29003_ADC_PD                 (1 << 6)
#define ISL29003_TIMING_INT             (1 << 5)
#define ISL29003_MODE_SHIFT             (2)
#define ISL29003_MODE_MASK              (0x3 << ISL29003_MODE_SHIFT)
#define ISL29003_RES_SHIFT              (0)
#define ISL29003_RES_MASK               (0x3 << ISL29003_RES_SHIFT)

#define ISL29003_REG_CONTROL            0x01
#define ISL29003_INT_FLG                (1 << 5)
#define ISL29003_RANGE_SHIFT            (2)
#define ISL29003_RANGE_MASK             (0x3 << ISL29003_RANGE_SHIFT)
#define ISL29003_INT_PERSISTS_SHIFT     (0)
#define ISL29003_INT_PERSISTS_MASK      (0xf << ISL29003_INT_PERSISTS_SHIFT)

#define ISL29003_REG_IRQ_THRESH_HI      0x02
#define ISL29003_REG_IRQ_THRESH_LO      0x03
#define ISL29003_REG_LSB_SENSOR         0x04
#define ISL29003_REG_MSB_SENSOR         0x05
#define ISL29003_REG_LSB_TIMER          0x06
#define ISL29003_REG_MSB_TIMER          0x07

#define ISL29003_NUM_CACHABLE_REGS      4

struct isl29003_data {
        struct i2c_client *client;
        struct mutex lock;
        u8 reg_cache[ISL29003_NUM_CACHABLE_REGS];
        u8 power_state_before_suspend;
};

static int gain_range[] = {
        1000, 4000, 16000, 64000
};

/*
 * register access helpers
 */

static int __isl29003_read_reg(struct i2c_client *client,
                               u32 reg, u8 mask, u8 shift)
{
        struct isl29003_data *data = i2c_get_clientdata(client);

        return (data->reg_cache[reg] & mask) >> shift;
}

static int __isl29003_write_reg(struct i2c_client *client,
                                u32 reg, u8 mask, u8 shift, u8 val)
{
        struct isl29003_data *data = i2c_get_clientdata(client);
        int ret = 0;
        u8 tmp;

        if (reg >= ISL29003_NUM_CACHABLE_REGS)
                return -EINVAL;

        mutex_lock(&data->lock);

        tmp = data->reg_cache[reg];
        tmp &= ~mask;
        tmp |= val << shift;

        ret = i2c_smbus_write_byte_data(client, reg, tmp);
        if (!ret)
                data->reg_cache[reg] = tmp;

        mutex_unlock(&data->lock);
        return ret;
}

/*
 * internally used functions
 */

/* range */
static int isl29003_get_range(struct i2c_client *client)
{
        return __isl29003_read_reg(client, ISL29003_REG_CONTROL,
                ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT);
}

static int isl29003_set_range(struct i2c_client *client, int range)
{
        return __isl29003_write_reg(client, ISL29003_REG_CONTROL,
                ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT, range);
}

/* resolution */
static int isl29003_get_resolution(struct i2c_client *client)
{
        return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
                ISL29003_RES_MASK, ISL29003_RES_SHIFT);
}

static int isl29003_set_resolution(struct i2c_client *client, int res)
{
        return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
                ISL29003_RES_MASK, ISL29003_RES_SHIFT, res);
}

/* mode */
static int isl29003_get_mode(struct i2c_client *client)
{
        return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
                ISL29003_MODE_MASK, ISL29003_MODE_SHIFT);
}

static int isl29003_set_mode(struct i2c_client *client, int mode)
{
        return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
                ISL29003_MODE_MASK, ISL29003_MODE_SHIFT, mode);
}

/* power_state */
static int isl29003_set_power_state(struct i2c_client *client, int state)
{
        return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
                                ISL29003_ADC_ENABLED | ISL29003_ADC_PD, 0,
                                state ? ISL29003_ADC_ENABLED : ISL29003_ADC_PD);
}

static int isl29003_get_power_state(struct i2c_client *client)
{
        struct isl29003_data *data = i2c_get_clientdata(client);
        u8 cmdreg = data->reg_cache[ISL29003_REG_COMMAND];

        return ~cmdreg & ISL29003_ADC_PD;
}

static int isl29003_get_adc_value(struct i2c_client *client)
{
        struct isl29003_data *data = i2c_get_clientdata(client);
        int lsb, msb, range, bitdepth;

        mutex_lock(&data->lock);
        lsb = i2c_smbus_read_byte_data(client, ISL29003_REG_LSB_SENSOR);

        if (lsb < 0) {
                mutex_unlock(&data->lock);
                return lsb;
        }

        msb = i2c_smbus_read_byte_data(client, ISL29003_REG_MSB_SENSOR);
        mutex_unlock(&data->lock);

        if (msb < 0)
                return msb;

        range = isl29003_get_range(client);
        bitdepth = (4 - isl29003_get_resolution(client)) * 4;
        return (((msb << 8) | lsb) * gain_range[range]) >> bitdepth;
}

/*
 * sysfs layer
 */

/* range */
static ssize_t isl29003_show_range(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);

        return sysfs_emit(buf, "%i\n", isl29003_get_range(client));
}

static ssize_t isl29003_store_range(struct device *dev,
                                    struct device_attribute *attr,
                                    const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        unsigned long val;
        int ret;

        ret = kstrtoul(buf, 10, &val);
        if (ret)
                return ret;

        if (val > 3)
                return -EINVAL;

        ret = isl29003_set_range(client, val);
        if (ret < 0)
                return ret;

        return count;
}

static DEVICE_ATTR(range, S_IWUSR | S_IRUGO,
                   isl29003_show_range, isl29003_store_range);


/* resolution */
static ssize_t isl29003_show_resolution(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);

        return sysfs_emit(buf, "%d\n", isl29003_get_resolution(client));
}

static ssize_t isl29003_store_resolution(struct device *dev,
                                         struct device_attribute *attr,
                                         const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        unsigned long val;
        int ret;

        ret = kstrtoul(buf, 10, &val);
        if (ret)
                return ret;

        if (val > 3)
                return -EINVAL;

        ret = isl29003_set_resolution(client, val);
        if (ret < 0)
                return ret;

        return count;
}

static DEVICE_ATTR(resolution, S_IWUSR | S_IRUGO,
                   isl29003_show_resolution, isl29003_store_resolution);

/* mode */
static ssize_t isl29003_show_mode(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);

        return sysfs_emit(buf, "%d\n", isl29003_get_mode(client));
}

static ssize_t isl29003_store_mode(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        unsigned long val;
        int ret;

        ret = kstrtoul(buf, 10, &val);
        if (ret)
                return ret;

        if (val > 2)
                return -EINVAL;

        ret = isl29003_set_mode(client, val);
        if (ret < 0)
                return ret;

        return count;
}

static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO,
                   isl29003_show_mode, isl29003_store_mode);


/* power state */
static ssize_t isl29003_show_power_state(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);

        return sysfs_emit(buf, "%d\n", isl29003_get_power_state(client));
}

static ssize_t isl29003_store_power_state(struct device *dev,
                                          struct device_attribute *attr,
                                          const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        unsigned long val;
        int ret;

        ret = kstrtoul(buf, 10, &val);
        if (ret)
                return ret;

        if (val > 1)
                return -EINVAL;

        ret = isl29003_set_power_state(client, val);
        return ret ? ret : count;
}

static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
                   isl29003_show_power_state, isl29003_store_power_state);


/* lux */
static ssize_t isl29003_show_lux(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);

        /* No LUX data if not operational */
        if (!isl29003_get_power_state(client))
                return -EBUSY;

        return sysfs_emit(buf, "%d\n", isl29003_get_adc_value(client));
}

static DEVICE_ATTR(lux, S_IRUGO, isl29003_show_lux, NULL);

static struct attribute *isl29003_attributes[] = {
        &dev_attr_range.attr,
        &dev_attr_resolution.attr,
        &dev_attr_mode.attr,
        &dev_attr_power_state.attr,
        &dev_attr_lux.attr,
        NULL
};

static const struct attribute_group isl29003_attr_group = {
        .attrs = isl29003_attributes,
};

static int isl29003_init_client(struct i2c_client *client)
{
        struct isl29003_data *data = i2c_get_clientdata(client);
        int i;

        /* read all the registers once to fill the cache.
         * if one of the reads fails, we consider the init failed */
        for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++) {
                int v = i2c_smbus_read_byte_data(client, i);

                if (v < 0)
                        return -ENODEV;

                data->reg_cache[i] = v;
        }

        /* set defaults */
        isl29003_set_range(client, 0);
        isl29003_set_resolution(client, 0);
        isl29003_set_mode(client, 0);
        isl29003_set_power_state(client, 0);

        return 0;
}

/*
 * I2C layer
 */

static int isl29003_probe(struct i2c_client *client)
{
        struct i2c_adapter *adapter = client->adapter;
        struct isl29003_data *data;
        int err = 0;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
                return -EIO;

        data = kzalloc_obj(struct isl29003_data);
        if (!data)
                return -ENOMEM;

        data->client = client;
        i2c_set_clientdata(client, data);
        mutex_init(&data->lock);

        /* initialize the ISL29003 chip */
        err = isl29003_init_client(client);
        if (err)
                goto exit_kfree;

        /* register sysfs hooks */
        err = sysfs_create_group(&client->dev.kobj, &isl29003_attr_group);
        if (err)
                goto exit_kfree;

        dev_info(&client->dev, "driver version %s enabled\n", DRIVER_VERSION);
        return 0;

exit_kfree:
        kfree(data);
        return err;
}

static void isl29003_remove(struct i2c_client *client)
{
        sysfs_remove_group(&client->dev.kobj, &isl29003_attr_group);
        isl29003_set_power_state(client, 0);
        kfree(i2c_get_clientdata(client));
}

#ifdef CONFIG_PM_SLEEP
static int isl29003_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct isl29003_data *data = i2c_get_clientdata(client);

        data->power_state_before_suspend = isl29003_get_power_state(client);
        return isl29003_set_power_state(client, 0);
}

static int isl29003_resume(struct device *dev)
{
        int i;
        struct i2c_client *client = to_i2c_client(dev);
        struct isl29003_data *data = i2c_get_clientdata(client);

        /* restore registers from cache */
        for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++)
                if (i2c_smbus_write_byte_data(client, i, data->reg_cache[i]))
                        return -EIO;

        return isl29003_set_power_state(client,
                data->power_state_before_suspend);
}

static SIMPLE_DEV_PM_OPS(isl29003_pm_ops, isl29003_suspend, isl29003_resume);
#define ISL29003_PM_OPS (&isl29003_pm_ops)

#else
#define ISL29003_PM_OPS NULL
#endif /* CONFIG_PM_SLEEP */

static const struct i2c_device_id isl29003_id[] = {
        { "isl29003" },
        {}
};
MODULE_DEVICE_TABLE(i2c, isl29003_id);

static struct i2c_driver isl29003_driver = {
        .driver = {
                .name   = ISL29003_DRV_NAME,
                .pm     = ISL29003_PM_OPS,
        },
        .probe = isl29003_probe,
        .remove = isl29003_remove,
        .id_table = isl29003_id,
};

module_i2c_driver(isl29003_driver);

MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
MODULE_DESCRIPTION("ISL29003 ambient light sensor driver");
MODULE_LICENSE("GPL v2");
MODULE_VERSION(DRIVER_VERSION);