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From:   Song Qiang <songqiang1304521@gmail.com>
Date:   Tue, 11 Sep 2018 10:19:33 +0800
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de,
        pmeerw@pmeerw.net, matt.ranostay@konsulko.com,
        kstewart@linuxfoundation.org, pombredanne@nexb.com,
        gregkh@linuxfoundation.org, ak@it-klinger.de,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iio: proximity: Add driver support for ST's VL53L0X ToF
 ranging sensor.
Message-ID: <20180911020746.GA12074@Eros>
References: <20180910144259.1339-1-songqiang.1304521@gmail.com>
 <20180910151243.GZ11447@smile.fi.intel.com>
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On Mon, Sep 10, 2018 at 06:12:43PM +0300, Andy Shevchenko wrote:
> On Mon, Sep 10, 2018 at 10:42:59PM +0800, Song Qiang wrote:
> > This driver was originally written by ST in 2016 as a misc input device,
> > and hasn't been maintained for a long time. I grabbed some code from
> > it's API and reformed it to a iio proximity device driver.
> > This version of driver uses i2c bus to talk to the sensor and
> > polling for measuring completes, so no irq line is needed.
> > This version of driver supports only one-shot mode, and it can be
> > tested with reading from
> > /sys/bus/iio/devices/iio:deviceX/in_distance_raw
> 
> Brief review for almost style issues...
> 
> > + *  vl53l0x-i2c.c - Support for STM VL53L0X FlightSense TOF
> > + *					Ranger Sensor on a i2c bus.
> 
> One line and without file name.
> 
> > + *
> > + *  Copyright (C) 2016 STMicroelectronics Imaging Division.
> > + *  Copyright (C) 2018 Song Qiang <songqiang.1304521@gmail.com>
> 
> > + *
> 
> Redundant
> 
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/slab.h>
> > +#include <linux/i2c.h>
> > +#include <linux/delay.h>
> > +#include <linux/kernel.h>
> 
> Keep above sorted.
> 
> > +#include <linux/iio/iio.h>
> > +
> > +#define VL53L0X_DRV_NAME			"vl53l0x"
> > +
> > +/* Device register map */
> > +#define VL_REG_SYSRANGE_START					0x000
> 
> 0x0000 ?
> 
> > +#define VL_REG_SYSRANGE_MODE_MASK				0x0F
> 
> GENMASK() ?
> 
> > +#define VL_REG_SYSRANGE_MODE_START_STOP			0x01
> > +#define VL_REG_SYSRANGE_MODE_SINGLESHOT			0x00
> > +#define VL_REG_SYSRANGE_MODE_BACKTOBACK			0x02
> > +#define VL_REG_SYSRANGE_MODE_TIMED				0x04
> > +#define VL_REG_SYSRANGE_MODE_HISTOGRAM			0x08
> 
> BIT() ?
> 
> Above comments related to below definitions as well.
> 
> > +
> > +#define VL_REG_SYS_THRESH_HIGH					0x000C
> > +#define VL_REG_SYS_THRESH_LOW					0x000E
> > +
> > +#define VL_REG_SYS_SEQUENCE_CFG					0x0001
> > +#define VL_REG_SYS_RANGE_CFG					0x0009
> > +#define VL_REG_SYS_INTERMEASUREMENT_PERIOD		0x0004
> > +
> > +#define VL_REG_SYS_INT_CFG_GPIO					0x000A
> 
> If you chose 0xHHHH format for the registers, please, keep the list of them sorted by the offset / address.
> 
> > +#define VL_REG_SYS_INT_GPIO_DISABLED			0x00
> > +#define VL_REG_SYS_INT_GPIO_LEVEL_LOW			0x01
> > +#define VL_REG_SYS_INT_GPIO_LEVEL_HIGH			0x02
> > +#define VL_REG_SYS_INT_GPIO_OUT_OF_WINDOW		0x03
> > +#define VL_REG_SYS_INT_GPIO_NEW_SAMPLE_READY	0x04
> > +#define VL_REG_GPIO_HV_MUX_ACTIVE_HIGH			0x0084
> > +#define VL_REG_SYS_INT_CLEAR					0x000B
> > +
> > +/* Result registers */
> > +#define VL_REG_RESULT_INT_STATUS				0x0013
> > +#define VL_REG_RESULT_RANGE_STATUS				0x0014
> > +
> > +#define VL_REG_RESULT_CORE_PAGE  1
> > +#define VL_REG_RESULT_CORE_AMBIENT_WINDOW_EVENTS_RTN	0x00BC
> > +#define VL_REG_RESULT_CORE_RANGING_TOTAL_EVENTS_RTN		0x00C0
> > +#define VL_REG_RESULT_CORE_AMBIENT_WINDOW_EVENTS_REF	0x00D0
> > +#define VL_REG_RESULT_CORE_RANGING_TOTAL_EVENTS_REF		0x00D4
> > +#define VL_REG_RESULT_PEAK_SIGNAL_RATE_REF				0x00B6
> > +
> > +/* Algo register */
> > +#define VL_REG_ALGO_PART_TO_PART_RANGE_OFFSET_MM		0x0028
> > +
> > +#define VL_REG_I2C_SLAVE_DEVICE_ADDRESS					0x008a
> > +
> > +/* Check Limit registers */
> > +#define VL_REG_MSRC_CFG_CONTROL						0x0060
> > +
> > +#define VL_REG_PRE_RANGE_CFG_MIN_SNR					0X0027
> > +#define VL_REG_PRE_RANGE_CFG_VALID_PHASE_LOW			0x0056
> > +#define VL_REG_PRE_RANGE_CFG_VALID_PHASE_HIGH			0x0057
> > +#define VL_REG_PRE_RANGE_MIN_COUNT_RATE_RTN_LIMIT		0x0064
> > +
> > +#define VL_REG_FINAL_RANGE_CFG_MIN_SNR					0X0067
> > +#define VL_REG_FINAL_RANGE_CFG_VALID_PHASE_LOW			0x0047
> > +#define VL_REG_FINAL_RANGE_CFG_VALID_PHASE_HIGH			0x0048
> > +#define VL_REG_FINAL_RANGE_CFG_MIN_COUNT_RATE_RTN_LIMIT	0x0044
> > +
> 
> > +#define VL_REG_PRE_RANGE_CFG_SIGMA_THRESH_HI			0X0061
> > +#define VL_REG_PRE_RANGE_CFG_SIGMA_THRESH_LO			0X0062
> 
> 0x
> 
> > +
> > +/* PRE RANGE registers */
> > +#define VL_REG_PRE_RANGE_CFG_VCSEL_PERIOD				0x0050
> > +#define VL_REG_PRE_RANGE_CFG_TIMEOUT_MACROP_HI			0x0051
> > +#define VL_REG_PRE_RANGE_CFG_TIMEOUT_MACROP_LO			0x0052
> > +
> > +#define VL_REG_SYS_HISTOGRAM_BIN					0x0081
> > +#define VL_REG_HISTOGRAM_CFG_INITIAL_PHASE_SELECT		0x0033
> > +#define VL_REG_HISTOGRAM_CFG_READOUT_CTRL				0x0055
> > +
> > +#define VL_REG_FINAL_RANGE_CFG_VCSEL_PERIOD				0x0070
> > +#define VL_REG_FINAL_RANGE_CFG_TIMEOUT_MACROP_HI		0x0071
> > +#define VL_REG_FINAL_RANGE_CFG_TIMEOUT_MACROP_LO		0x0072
> > +#define VL_REG_CROSSTALK_COMPENSATION_PEAK_RATE_MCPS	0x0020
> > +
> > +#define VL_REG_MSRC_CFG_TIMEOUT_MACROP					0x0046
> > +
> > +#define VL_REG_SOFT_RESET_GO2_SOFT_RESET_N				0x00bf
> > +#define VL_REG_IDENTIFICATION_MODEL_ID					0x00c0
> > +#define VL_REG_IDENTIFICATION_REVISION_ID				0x00c2
> > +
> > +#define VL_REG_OSC_CALIBRATE_VAL					0x00f8
> > +
> > +#define VL_SIGMA_ESTIMATE_MAX_VALUE					65535
> > +/* equivalent to a range sigma of 655.35mm */
> > +
> > +#define VL_REG_GLOBAL_CFG_VCSEL_WIDTH					0x032
> > +#define VL_REG_GLOBAL_CFG_SPAD_ENABLES_REF_0			0x0B0
> > +#define VL_REG_GLOBAL_CFG_SPAD_ENABLES_REF_1			0x0B1
> > +#define VL_REG_GLOBAL_CFG_SPAD_ENABLES_REF_2			0x0B2
> > +#define VL_REG_GLOBAL_CFG_SPAD_ENABLES_REF_3			0x0B3
> > +#define VL_REG_GLOBAL_CFG_SPAD_ENABLES_REF_4			0x0B4
> > +#define VL_REG_GLOBAL_CFG_SPAD_ENABLES_REF_5			0x0B5
> > +#define VL_REG_GLOBAL_CFG_REF_EN_START_SELECT			0xB6
> 
> 0x00 or 0x for prefix?
> 
> > +#define VL_REG_DYNAMIC_SPAD_NUM_REQUESTED_REF_SPAD		0x4E /* 0x14E */
> > +#define VL_REG_DYNAMIC_SPAD_REF_EN_START_OFFSET			0x4F /* 0x14F */
> > +#define VL_REG_POWER_MANAGEMENT_GO1_POWER_FORCE			0x80
> > +
> > +/*
> > + * Speed of light in um per 1E-10 Seconds
> > + */
> > +#define VL_SPEED_OF_LIGHT_IN_AIR					2997
> > +#define VL_REG_VHV_CFG_PAD_SCL_SDA__EXTSUP_HV			0x0089
> > +#define VL_REG_ALGO_PHASECAL_LIM			0x0030 /* 0x130 */
> > +#define VL_REG_ALGO_PHASECAL_CFG_TIMEOUT				0x0030
> > +
> > +struct vl53l0x_data {
> > +	struct i2c_client *client;
> > +	struct mutex lock;
> > +	int	useLongRange;
> 
> noCamelCasePlease.
> 
> > +};
> > +
> > +static int vl53l0x_read_proximity(struct vl53l0x_data *data,
> > +				const struct iio_chan_spec *chan,
> > +				int *val)
> > +{
> > +	int ret;
> > +	struct i2c_client *client = data->client;
> > +	int tries = 20;
> 
> unsigned int
> 
> > +	u8 buffer[12];
> > +	struct i2c_msg msg[2];
> > +	u8 write_command = VL_REG_RESULT_RANGE_STATUS;
> 
> Reversed xmas tree order, please
> 
> > +
> > +	ret = i2c_smbus_write_byte_data(data->client,
> > +					VL_REG_SYSRANGE_START, 1);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	while (tries-- > 0) {
> 
> 
> Better form is
> 
> do {
> 	...
> } while (--tries);
> if (!tries)
> 	return -ETIMEDOUT;
> 
> > +		ret = i2c_smbus_read_byte_data(data->client,
> > +						VL_REG_RESULT_RANGE_STATUS);
> > +		if (ret < 0)
> > +			return ret;
> > +
> > +		if (ret & 0x01)
> > +			break;
> > +		usleep_range(1000, 5000);
> > +	}
> > +
> > +	if (tries < 0)
> > +		return -ETIMEDOUT;
> > +
> > +	msg[0].addr = client->addr;
> > +	msg[0].buf = &write_command;
> > +	msg[0].len = 1;
> > +	msg[0].flags = client->flags | I2C_M_STOP;
> > +
> > +	msg[1].addr = client->addr;
> > +	msg[1].buf = buffer;
> > +	msg[1].len = 12;
> > +	msg[1].flags = client->flags | I2C_M_RD;
> > +
> > +	ret = i2c_transfer(client->adapter, msg, 2);
> > +
> 
> > +	if (ret != 2) {
> 
> Shouldn't be simple if (ret < 0)
> 
> > +		pr_err("vl53l0x: consecutively read error. ");
> 
> dev_err(...);
> Also check other prints.
> 
> > +		return ret;
> > +	}
> > +
> > +	*val = __le16_to_cpu((buffer[10] << 8) + buffer[11]);
> > +
> > +	return 0;
> > +}
> 
> > +static int vl53l0x_probe(struct i2c_client *client,
> > +				   const struct i2c_device_id *id)
> 
> (see below about ->probe_new() hook)
> 
> > +{
> > +	int ret;
> > +	struct vl53l0x_data *data;
> > +	struct iio_dev *indio_dev;
> > +
> > +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	data = iio_priv(indio_dev);
> > +	data->client = client;
> > +	i2c_set_clientdata(client, indio_dev);
> > +	mutex_init(&data->lock);
> > +
> > +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE))
> > +		return -EOPNOTSUPP;
> > +
> > +	indio_dev->dev.parent = &client->dev;
> > +	indio_dev->name = VL53L0X_DRV_NAME;
> > +	indio_dev->info = &vl53l0x_info;
> > +	indio_dev->channels = vl53l0x_channels;
> > +	indio_dev->num_channels = ARRAY_SIZE(vl53l0x_channels);
> > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > +
> 
> > +	//probe 0xc0 if the value is 0xEE.
> 
> Useless commwnt  for now
> 
> > +
> > +	ret = iio_device_register(indio_dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	dev_set_drvdata(&client->dev, data);
> > +
> > +	return 0;
> > +}
> > +
> > +static int vl53l0x_remove(struct i2c_client *client)
> > +{
> > +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> > +	struct vl53l0x_data *data = iio_priv(indio_dev);
> > +
> > +	iio_device_unregister(indio_dev);
> 
> > +	kfree(data);
> 
> how did you test it?
> 
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct i2c_device_id vl53l0x_id[] = {
> > +	{ VL53L0X_DRV_NAME, 0 },
> 
> > +	{ },
> Terminator better w/o comma
> 
> > +};
> > +MODULE_DEVICE_TABLE(i2c, vl53l0x_id);
> 
> Do you expect this to be used at all?
> 
> > +
> > +static const struct of_device_id st_vl53l0x_dt_match[] = {
> > +	{ .compatible = "st,vl53l0x-i2c", },
> 
> > +	{ },
> 
> Terminator better w/o comma
> 
> > +};
> > +
> > +static struct i2c_driver vl53l0x_driver = {
> > +	.driver = {
> > +		.name	= VL53L0X_DRV_NAME,
> 
> > +		.owner	= THIS_MODULE,
> 
> This done by macro.
> 
> > +		.of_match_table = st_vl53l0x_dt_match,
> > +	},
> > +	.probe	= vl53l0x_probe,
> 
> ->probe_new(), please.
> 
> > +	.remove	= vl53l0x_remove,
> > +	.id_table = vl53l0x_id,
> > +};
> > +module_i2c_driver(vl53l0x_driver);
> > +
> > +MODULE_AUTHOR("Song Qiang <songqiang.1304521@gmail.com>");
> > +MODULE_DESCRIPTION("ST vl53l0x ToF ranging sensor");
> > +MODULE_LICENSE("GPL");
> > -- 
> > 2.17.1
> > 
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

Hi Andy,

Sorry for the mess in register table, I took it from ST's
API and has only checked it with the checkpatch.pl. 
I didn't know about probe_new() when I was writing this driver,
I'll see what it does and try to use it. 
I'll check the other problems you listed and clean up the
register table.

Thanks a lot for the reviewing.

Yours,
Song Qiang