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linux/drivers/iio/light/vl6180.c
Lars-Peter Clausen ed0ccf6d22 iio: vl6180: Use DIV_ROUND_CLOSEST() instead of open-coding it 
Use DIV_ROUND_CLOSEST() instead of open-coding it. This documents intent
and makes it more clear what is going on for the casual reviewer.

Generated using the following the Coccinelle semantic patch.

// <smpl>
@r1@
expression x;
constant C1;
constant C2;
@@
 ((x) + C1) / C2

@script:python@
C1 << r1.C1;
C2 << r1.C2;
@@
try:
	if int(C1) * 2 != int(C2):
		cocci.include_match(False)
except:
	cocci.include_match(False)

@@
expression r1.x;
constant r1.C1;
constant r1.C2;
@@
-(((x) + C1) / C2)
+DIV_ROUND_CLOSEST(x, C2)
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/20201227171126.28216-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-01-09 21:52:45 +00:00

552 lines
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// SPDX-License-Identifier: GPL-2.0-only
/*
* vl6180.c - Support for STMicroelectronics VL6180 ALS, range and proximity
* sensor
*
* Copyright 2017 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
* Copyright 2017 Manivannan Sadhasivam <manivannanece23@gmail.com>
*
* IIO driver for VL6180 (7-bit I2C slave address 0x29)
*
* Range: 0 to 100mm
* ALS: < 1 Lux up to 100 kLux
* IR: 850nm
*
* TODO: irq, threshold events, continuous mode, hardware buffer
*/
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/util_macros.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define VL6180_DRV_NAME "vl6180"
/* Device identification register and value */
#define VL6180_MODEL_ID 0x000
#define VL6180_MODEL_ID_VAL 0xb4
/* Configuration registers */
#define VL6180_INTR_CONFIG 0x014
#define VL6180_INTR_CLEAR 0x015
#define VL6180_OUT_OF_RESET 0x016
#define VL6180_HOLD 0x017
#define VL6180_RANGE_START 0x018
#define VL6180_ALS_START 0x038
#define VL6180_ALS_GAIN 0x03f
#define VL6180_ALS_IT 0x040
/* Status registers */
#define VL6180_RANGE_STATUS 0x04d
#define VL6180_ALS_STATUS 0x04e
#define VL6180_INTR_STATUS 0x04f
/* Result value registers */
#define VL6180_ALS_VALUE 0x050
#define VL6180_RANGE_VALUE 0x062
#define VL6180_RANGE_RATE 0x066
/* bits of the RANGE_START and ALS_START register */
#define VL6180_MODE_CONT BIT(1) /* continuous mode */
#define VL6180_STARTSTOP BIT(0) /* start measurement, auto-reset */
/* bits of the INTR_STATUS and INTR_CONFIG register */
#define VL6180_ALS_READY BIT(5)
#define VL6180_RANGE_READY BIT(2)
/* bits of the INTR_CLEAR register */
#define VL6180_CLEAR_ERROR BIT(2)
#define VL6180_CLEAR_ALS BIT(1)
#define VL6180_CLEAR_RANGE BIT(0)
/* bits of the HOLD register */
#define VL6180_HOLD_ON BIT(0)
/* default value for the ALS_IT register */
#define VL6180_ALS_IT_100 0x63 /* 100 ms */
/* values for the ALS_GAIN register */
#define VL6180_ALS_GAIN_1 0x46
#define VL6180_ALS_GAIN_1_25 0x45
#define VL6180_ALS_GAIN_1_67 0x44
#define VL6180_ALS_GAIN_2_5 0x43
#define VL6180_ALS_GAIN_5 0x42
#define VL6180_ALS_GAIN_10 0x41
#define VL6180_ALS_GAIN_20 0x40
#define VL6180_ALS_GAIN_40 0x47
struct vl6180_data {
struct i2c_client *client;
struct mutex lock;
unsigned int als_gain_milli;
unsigned int als_it_ms;
};
enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
/**
* struct vl6180_chan_regs - Registers for accessing channels
* @drdy_mask: Data ready bit in status register
* @start_reg: Conversion start register
* @value_reg: Result value register
* @word: Register word length
*/
struct vl6180_chan_regs {
u8 drdy_mask;
u16 start_reg, value_reg;
bool word;
};
static const struct vl6180_chan_regs vl6180_chan_regs_table[] = {
[VL6180_ALS] = {
.drdy_mask = VL6180_ALS_READY,
.start_reg = VL6180_ALS_START,
.value_reg = VL6180_ALS_VALUE,
.word = true,
},
[VL6180_RANGE] = {
.drdy_mask = VL6180_RANGE_READY,
.start_reg = VL6180_RANGE_START,
.value_reg = VL6180_RANGE_VALUE,
.word = false,
},
[VL6180_PROX] = {
.drdy_mask = VL6180_RANGE_READY,
.start_reg = VL6180_RANGE_START,
.value_reg = VL6180_RANGE_RATE,
.word = true,
},
};
static int vl6180_read(struct i2c_client *client, u16 cmd, void *databuf,
u8 len)
{
__be16 cmdbuf = cpu_to_be16(cmd);
struct i2c_msg msgs[2] = {
{ .addr = client->addr, .len = sizeof(cmdbuf), .buf = (u8 *) &cmdbuf },
{ .addr = client->addr, .len = len, .buf = databuf,
.flags = I2C_M_RD } };
int ret;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0)
dev_err(&client->dev, "failed reading register 0x%04x\n", cmd);
return ret;
}
static int vl6180_read_byte(struct i2c_client *client, u16 cmd)
{
u8 data;
int ret;
ret = vl6180_read(client, cmd, &data, sizeof(data));
if (ret < 0)
return ret;
return data;
}
static int vl6180_read_word(struct i2c_client *client, u16 cmd)
{
__be16 data;
int ret;
ret = vl6180_read(client, cmd, &data, sizeof(data));
if (ret < 0)
return ret;
return be16_to_cpu(data);
}
static int vl6180_write_byte(struct i2c_client *client, u16 cmd, u8 val)
{
u8 buf[3];
struct i2c_msg msgs[1] = {
{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
int ret;
buf[0] = cmd >> 8;
buf[1] = cmd & 0xff;
buf[2] = val;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0) {
dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
return ret;
}
return 0;
}
static int vl6180_write_word(struct i2c_client *client, u16 cmd, u16 val)
{
__be16 buf[2];
struct i2c_msg msgs[1] = {
{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
int ret;
buf[0] = cpu_to_be16(cmd);
buf[1] = cpu_to_be16(val);
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0) {
dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
return ret;
}
return 0;
}
static int vl6180_measure(struct vl6180_data *data, int addr)
{
struct i2c_client *client = data->client;
int tries = 20, ret;
u16 value;
mutex_lock(&data->lock);
/* Start single shot measurement */
ret = vl6180_write_byte(client,
vl6180_chan_regs_table[addr].start_reg, VL6180_STARTSTOP);
if (ret < 0)
goto fail;
while (tries--) {
ret = vl6180_read_byte(client, VL6180_INTR_STATUS);
if (ret < 0)
goto fail;
if (ret & vl6180_chan_regs_table[addr].drdy_mask)
break;
msleep(20);
}
if (tries < 0) {
ret = -EIO;
goto fail;
}
/* Read result value from appropriate registers */
ret = vl6180_chan_regs_table[addr].word ?
vl6180_read_word(client, vl6180_chan_regs_table[addr].value_reg) :
vl6180_read_byte(client, vl6180_chan_regs_table[addr].value_reg);
if (ret < 0)
goto fail;
value = ret;
/* Clear the interrupt flag after data read */
ret = vl6180_write_byte(client, VL6180_INTR_CLEAR,
VL6180_CLEAR_ERROR | VL6180_CLEAR_ALS | VL6180_CLEAR_RANGE);
if (ret < 0)
goto fail;
ret = value;
fail:
mutex_unlock(&data->lock);
return ret;
}
static const struct iio_chan_spec vl6180_channels[] = {
{
.type = IIO_LIGHT,
.address = VL6180_ALS,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_INT_TIME) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_HARDWAREGAIN),
}, {
.type = IIO_DISTANCE,
.address = VL6180_RANGE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
}, {
.type = IIO_PROXIMITY,
.address = VL6180_PROX,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
}
};
/*
* Available Ambient Light Sensor gain settings, 1/1000th, and
* corresponding setting for the VL6180_ALS_GAIN register
*/
static const int vl6180_als_gain_tab[8] = {
1000, 1250, 1670, 2500, 5000, 10000, 20000, 40000
};
static const u8 vl6180_als_gain_tab_bits[8] = {
VL6180_ALS_GAIN_1, VL6180_ALS_GAIN_1_25,
VL6180_ALS_GAIN_1_67, VL6180_ALS_GAIN_2_5,
VL6180_ALS_GAIN_5, VL6180_ALS_GAIN_10,
VL6180_ALS_GAIN_20, VL6180_ALS_GAIN_40
};
static int vl6180_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct vl6180_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = vl6180_measure(data, chan->address);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_INT_TIME:
*val = data->als_it_ms;
*val2 = 1000;
return IIO_VAL_FRACTIONAL;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_LIGHT:
/* one ALS count is 0.32 Lux @ gain 1, IT 100 ms */
*val = 32000; /* 0.32 * 1000 * 100 */
*val2 = data->als_gain_milli * data->als_it_ms;
return IIO_VAL_FRACTIONAL;
case IIO_DISTANCE:
*val = 0; /* sensor reports mm, scale to meter */
*val2 = 1000;
break;
default:
return -EINVAL;
}
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_HARDWAREGAIN:
*val = data->als_gain_milli;
*val2 = 1000;
return IIO_VAL_FRACTIONAL;
default:
return -EINVAL;
}
}
static IIO_CONST_ATTR(als_gain_available, "1 1.25 1.67 2.5 5 10 20 40");
static struct attribute *vl6180_attributes[] = {
&iio_const_attr_als_gain_available.dev_attr.attr,
NULL
};
static const struct attribute_group vl6180_attribute_group = {
.attrs = vl6180_attributes,
};
/* HOLD is needed before updating any config registers */
static int vl6180_hold(struct vl6180_data *data, bool hold)
{
return vl6180_write_byte(data->client, VL6180_HOLD,
hold ? VL6180_HOLD_ON : 0);
}
static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2)
{
int i, ret, gain;
if (val < 1 || val > 40)
return -EINVAL;
gain = (val * 1000000 + val2) / 1000;
if (gain < 1 || gain > 40000)
return -EINVAL;
i = find_closest(gain, vl6180_als_gain_tab,
ARRAY_SIZE(vl6180_als_gain_tab));
mutex_lock(&data->lock);
ret = vl6180_hold(data, true);
if (ret < 0)
goto fail;
ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN,
vl6180_als_gain_tab_bits[i]);
if (ret >= 0)
data->als_gain_milli = vl6180_als_gain_tab[i];
fail:
vl6180_hold(data, false);
mutex_unlock(&data->lock);
return ret;
}
static int vl6180_set_it(struct vl6180_data *data, int val, int val2)
{
int ret, it_ms;
it_ms = DIV_ROUND_CLOSEST(val2, 1000); /* round to ms */
if (val != 0 || it_ms < 1 || it_ms > 512)
return -EINVAL;
mutex_lock(&data->lock);
ret = vl6180_hold(data, true);
if (ret < 0)
goto fail;
ret = vl6180_write_word(data->client, VL6180_ALS_IT, it_ms - 1);
if (ret >= 0)
data->als_it_ms = it_ms;
fail:
vl6180_hold(data, false);
mutex_unlock(&data->lock);
return ret;
}
static int vl6180_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct vl6180_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_INT_TIME:
return vl6180_set_it(data, val, val2);
case IIO_CHAN_INFO_HARDWAREGAIN:
if (chan->type != IIO_LIGHT)
return -EINVAL;
return vl6180_set_als_gain(data, val, val2);
default:
return -EINVAL;
}
}
static const struct iio_info vl6180_info = {
.read_raw = vl6180_read_raw,
.write_raw = vl6180_write_raw,
.attrs = &vl6180_attribute_group,
};
static int vl6180_init(struct vl6180_data *data)
{
struct i2c_client *client = data->client;
int ret;
ret = vl6180_read_byte(client, VL6180_MODEL_ID);
if (ret < 0)
return ret;
if (ret != VL6180_MODEL_ID_VAL) {
dev_err(&client->dev, "invalid model ID %02x\n", ret);
return -ENODEV;
}
ret = vl6180_hold(data, true);
if (ret < 0)
return ret;
ret = vl6180_read_byte(client, VL6180_OUT_OF_RESET);
if (ret < 0)
return ret;
/*
* Detect false reset condition here. This bit is always set when the
* system comes out of reset.
*/
if (ret != 0x01)
dev_info(&client->dev, "device is not fresh out of reset\n");
/* Enable ALS and Range ready interrupts */
ret = vl6180_write_byte(client, VL6180_INTR_CONFIG,
VL6180_ALS_READY | VL6180_RANGE_READY);
if (ret < 0)
return ret;
/* ALS integration time: 100ms */
data->als_it_ms = 100;
ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
if (ret < 0)
return ret;
/* ALS gain: 1 */
data->als_gain_milli = 1000;
ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1);
if (ret < 0)
return ret;
ret = vl6180_write_byte(client, VL6180_OUT_OF_RESET, 0x00);
if (ret < 0)
return ret;
return vl6180_hold(data, false);
}
static int vl6180_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct vl6180_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->lock);
indio_dev->info = &vl6180_info;
indio_dev->channels = vl6180_channels;
indio_dev->num_channels = ARRAY_SIZE(vl6180_channels);
indio_dev->name = VL6180_DRV_NAME;
indio_dev->modes = INDIO_DIRECT_MODE;
ret = vl6180_init(data);
if (ret < 0)
return ret;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct of_device_id vl6180_of_match[] = {
{ .compatible = "st,vl6180", },
{ },
};
MODULE_DEVICE_TABLE(of, vl6180_of_match);
static const struct i2c_device_id vl6180_id[] = {
{ "vl6180", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, vl6180_id);
static struct i2c_driver vl6180_driver = {
.driver = {
.name = VL6180_DRV_NAME,
.of_match_table = vl6180_of_match,
},
.probe = vl6180_probe,
.id_table = vl6180_id,
};
module_i2c_driver(vl6180_driver);
MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
MODULE_AUTHOR("Manivannan Sadhasivam <manivannanece23@gmail.com>");
MODULE_DESCRIPTION("STMicro VL6180 ALS, range and proximity sensor driver");
MODULE_LICENSE("GPL");
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