cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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veml6030.c (22221B)


      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * VEML6030 Ambient Light Sensor
      4 *
      5 * Copyright (c) 2019, Rishi Gupta <gupt21@gmail.com>
      6 *
      7 * Datasheet: https://www.vishay.com/docs/84366/veml6030.pdf
      8 * Appnote-84367: https://www.vishay.com/docs/84367/designingveml6030.pdf
      9 */
     10
     11#include <linux/module.h>
     12#include <linux/i2c.h>
     13#include <linux/err.h>
     14#include <linux/regmap.h>
     15#include <linux/interrupt.h>
     16#include <linux/pm_runtime.h>
     17#include <linux/iio/iio.h>
     18#include <linux/iio/sysfs.h>
     19#include <linux/iio/events.h>
     20
     21/* Device registers */
     22#define VEML6030_REG_ALS_CONF   0x00
     23#define VEML6030_REG_ALS_WH     0x01
     24#define VEML6030_REG_ALS_WL     0x02
     25#define VEML6030_REG_ALS_PSM    0x03
     26#define VEML6030_REG_ALS_DATA   0x04
     27#define VEML6030_REG_WH_DATA    0x05
     28#define VEML6030_REG_ALS_INT    0x06
     29
     30/* Bit masks for specific functionality */
     31#define VEML6030_ALS_IT       GENMASK(9, 6)
     32#define VEML6030_PSM          GENMASK(2, 1)
     33#define VEML6030_ALS_PERS     GENMASK(5, 4)
     34#define VEML6030_ALS_GAIN     GENMASK(12, 11)
     35#define VEML6030_PSM_EN       BIT(0)
     36#define VEML6030_INT_TH_LOW   BIT(15)
     37#define VEML6030_INT_TH_HIGH  BIT(14)
     38#define VEML6030_ALS_INT_EN   BIT(1)
     39#define VEML6030_ALS_SD       BIT(0)
     40
     41/*
     42 * The resolution depends on both gain and integration time. The
     43 * cur_resolution stores one of the resolution mentioned in the
     44 * table during startup and gets updated whenever integration time
     45 * or gain is changed.
     46 *
     47 * Table 'resolution and maximum detection range' in appnote 84367
     48 * is visualized as a 2D array. The cur_gain stores index of gain
     49 * in this table (0-3) while the cur_integration_time holds index
     50 * of integration time (0-5).
     51 */
     52struct veml6030_data {
     53	struct i2c_client *client;
     54	struct regmap *regmap;
     55	int cur_resolution;
     56	int cur_gain;
     57	int cur_integration_time;
     58};
     59
     60/* Integration time available in seconds */
     61static IIO_CONST_ATTR(in_illuminance_integration_time_available,
     62				"0.025 0.05 0.1 0.2 0.4 0.8");
     63
     64/*
     65 * Scale is 1/gain. Value 0.125 is ALS gain x (1/8), 0.25 is
     66 * ALS gain x (1/4), 1.0 = ALS gain x 1 and 2.0 is ALS gain x 2.
     67 */
     68static IIO_CONST_ATTR(in_illuminance_scale_available,
     69				"0.125 0.25 1.0 2.0");
     70
     71static struct attribute *veml6030_attributes[] = {
     72	&iio_const_attr_in_illuminance_integration_time_available.dev_attr.attr,
     73	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
     74	NULL
     75};
     76
     77static const struct attribute_group veml6030_attr_group = {
     78	.attrs = veml6030_attributes,
     79};
     80
     81/*
     82 * Persistence = 1/2/4/8 x integration time
     83 * Minimum time for which light readings must stay above configured
     84 * threshold to assert the interrupt.
     85 */
     86static const char * const period_values[] = {
     87		"0.1 0.2 0.4 0.8",
     88		"0.2 0.4 0.8 1.6",
     89		"0.4 0.8 1.6 3.2",
     90		"0.8 1.6 3.2 6.4",
     91		"0.05 0.1 0.2 0.4",
     92		"0.025 0.050 0.1 0.2"
     93};
     94
     95/*
     96 * Return list of valid period values in seconds corresponding to
     97 * the currently active integration time.
     98 */
     99static ssize_t in_illuminance_period_available_show(struct device *dev,
    100				struct device_attribute *attr, char *buf)
    101{
    102	int ret, reg, x;
    103	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
    104	struct veml6030_data *data = iio_priv(indio_dev);
    105
    106	ret = regmap_read(data->regmap, VEML6030_REG_ALS_CONF, &reg);
    107	if (ret) {
    108		dev_err(&data->client->dev,
    109				"can't read als conf register %d\n", ret);
    110		return ret;
    111	}
    112
    113	ret = ((reg >> 6) & 0xF);
    114	switch (ret) {
    115	case 0:
    116	case 1:
    117	case 2:
    118	case 3:
    119		x = ret;
    120		break;
    121	case 8:
    122		x = 4;
    123		break;
    124	case 12:
    125		x = 5;
    126		break;
    127	default:
    128		return -EINVAL;
    129	}
    130
    131	return sysfs_emit(buf, "%s\n", period_values[x]);
    132}
    133
    134static IIO_DEVICE_ATTR_RO(in_illuminance_period_available, 0);
    135
    136static struct attribute *veml6030_event_attributes[] = {
    137	&iio_dev_attr_in_illuminance_period_available.dev_attr.attr,
    138	NULL
    139};
    140
    141static const struct attribute_group veml6030_event_attr_group = {
    142	.attrs = veml6030_event_attributes,
    143};
    144
    145static int veml6030_als_pwr_on(struct veml6030_data *data)
    146{
    147	return regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
    148				 VEML6030_ALS_SD, 0);
    149}
    150
    151static int veml6030_als_shut_down(struct veml6030_data *data)
    152{
    153	return regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
    154				 VEML6030_ALS_SD, 1);
    155}
    156
    157static void veml6030_als_shut_down_action(void *data)
    158{
    159	veml6030_als_shut_down(data);
    160}
    161
    162static const struct iio_event_spec veml6030_event_spec[] = {
    163	{
    164		.type = IIO_EV_TYPE_THRESH,
    165		.dir = IIO_EV_DIR_RISING,
    166		.mask_separate = BIT(IIO_EV_INFO_VALUE),
    167	}, {
    168		.type = IIO_EV_TYPE_THRESH,
    169		.dir = IIO_EV_DIR_FALLING,
    170		.mask_separate = BIT(IIO_EV_INFO_VALUE),
    171	}, {
    172		.type = IIO_EV_TYPE_THRESH,
    173		.dir = IIO_EV_DIR_EITHER,
    174		.mask_separate = BIT(IIO_EV_INFO_PERIOD) |
    175		BIT(IIO_EV_INFO_ENABLE),
    176	},
    177};
    178
    179/* Channel number */
    180enum veml6030_chan {
    181	CH_ALS,
    182	CH_WHITE,
    183};
    184
    185static const struct iio_chan_spec veml6030_channels[] = {
    186	{
    187		.type = IIO_LIGHT,
    188		.channel = CH_ALS,
    189		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
    190				BIT(IIO_CHAN_INFO_PROCESSED) |
    191				BIT(IIO_CHAN_INFO_INT_TIME) |
    192				BIT(IIO_CHAN_INFO_SCALE),
    193		.event_spec = veml6030_event_spec,
    194		.num_event_specs = ARRAY_SIZE(veml6030_event_spec),
    195	},
    196	{
    197		.type = IIO_INTENSITY,
    198		.channel = CH_WHITE,
    199		.modified = 1,
    200		.channel2 = IIO_MOD_LIGHT_BOTH,
    201		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
    202				BIT(IIO_CHAN_INFO_PROCESSED),
    203	},
    204};
    205
    206static const struct regmap_config veml6030_regmap_config = {
    207	.name = "veml6030_regmap",
    208	.reg_bits = 8,
    209	.val_bits = 16,
    210	.max_register = VEML6030_REG_ALS_INT,
    211	.val_format_endian = REGMAP_ENDIAN_LITTLE,
    212};
    213
    214static int veml6030_get_intgrn_tm(struct iio_dev *indio_dev,
    215						int *val, int *val2)
    216{
    217	int ret, reg;
    218	struct veml6030_data *data = iio_priv(indio_dev);
    219
    220	ret = regmap_read(data->regmap, VEML6030_REG_ALS_CONF, &reg);
    221	if (ret) {
    222		dev_err(&data->client->dev,
    223				"can't read als conf register %d\n", ret);
    224		return ret;
    225	}
    226
    227	switch ((reg >> 6) & 0xF) {
    228	case 0:
    229		*val2 = 100000;
    230		break;
    231	case 1:
    232		*val2 = 200000;
    233		break;
    234	case 2:
    235		*val2 = 400000;
    236		break;
    237	case 3:
    238		*val2 = 800000;
    239		break;
    240	case 8:
    241		*val2 = 50000;
    242		break;
    243	case 12:
    244		*val2 = 25000;
    245		break;
    246	default:
    247		return -EINVAL;
    248	}
    249
    250	*val = 0;
    251	return IIO_VAL_INT_PLUS_MICRO;
    252}
    253
    254static int veml6030_set_intgrn_tm(struct iio_dev *indio_dev,
    255						int val, int val2)
    256{
    257	int ret, new_int_time, int_idx;
    258	struct veml6030_data *data = iio_priv(indio_dev);
    259
    260	if (val)
    261		return -EINVAL;
    262
    263	switch (val2) {
    264	case 25000:
    265		new_int_time = 0x300;
    266		int_idx = 5;
    267		break;
    268	case 50000:
    269		new_int_time = 0x200;
    270		int_idx = 4;
    271		break;
    272	case 100000:
    273		new_int_time = 0x00;
    274		int_idx = 3;
    275		break;
    276	case 200000:
    277		new_int_time = 0x40;
    278		int_idx = 2;
    279		break;
    280	case 400000:
    281		new_int_time = 0x80;
    282		int_idx = 1;
    283		break;
    284	case 800000:
    285		new_int_time = 0xC0;
    286		int_idx = 0;
    287		break;
    288	default:
    289		return -EINVAL;
    290	}
    291
    292	ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
    293					VEML6030_ALS_IT, new_int_time);
    294	if (ret) {
    295		dev_err(&data->client->dev,
    296				"can't update als integration time %d\n", ret);
    297		return ret;
    298	}
    299
    300	/*
    301	 * Cache current integration time and update resolution. For every
    302	 * increase in integration time to next level, resolution is halved
    303	 * and vice-versa.
    304	 */
    305	if (data->cur_integration_time < int_idx)
    306		data->cur_resolution <<= int_idx - data->cur_integration_time;
    307	else if (data->cur_integration_time > int_idx)
    308		data->cur_resolution >>= data->cur_integration_time - int_idx;
    309
    310	data->cur_integration_time = int_idx;
    311
    312	return ret;
    313}
    314
    315static int veml6030_read_persistence(struct iio_dev *indio_dev,
    316						int *val, int *val2)
    317{
    318	int ret, reg, period, x, y;
    319	struct veml6030_data *data = iio_priv(indio_dev);
    320
    321	ret = veml6030_get_intgrn_tm(indio_dev, &x, &y);
    322	if (ret < 0)
    323		return ret;
    324
    325	ret = regmap_read(data->regmap, VEML6030_REG_ALS_CONF, &reg);
    326	if (ret) {
    327		dev_err(&data->client->dev,
    328				"can't read als conf register %d\n", ret);
    329	}
    330
    331	/* integration time multiplied by 1/2/4/8 */
    332	period = y * (1 << ((reg >> 4) & 0x03));
    333
    334	*val = period / 1000000;
    335	*val2 = period % 1000000;
    336
    337	return IIO_VAL_INT_PLUS_MICRO;
    338}
    339
    340static int veml6030_write_persistence(struct iio_dev *indio_dev,
    341						int val, int val2)
    342{
    343	int ret, period, x, y;
    344	struct veml6030_data *data = iio_priv(indio_dev);
    345
    346	ret = veml6030_get_intgrn_tm(indio_dev, &x, &y);
    347	if (ret < 0)
    348		return ret;
    349
    350	if (!val) {
    351		period = val2 / y;
    352	} else {
    353		if ((val == 1) && (val2 == 600000))
    354			period = 1600000 / y;
    355		else if ((val == 3) && (val2 == 200000))
    356			period = 3200000 / y;
    357		else if ((val == 6) && (val2 == 400000))
    358			period = 6400000 / y;
    359		else
    360			period = -1;
    361	}
    362
    363	if (period <= 0 || period > 8 || hweight8(period) != 1)
    364		return -EINVAL;
    365
    366	ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
    367				VEML6030_ALS_PERS, (ffs(period) - 1) << 4);
    368	if (ret)
    369		dev_err(&data->client->dev,
    370				"can't set persistence value %d\n", ret);
    371
    372	return ret;
    373}
    374
    375static int veml6030_set_als_gain(struct iio_dev *indio_dev,
    376						int val, int val2)
    377{
    378	int ret, new_gain, gain_idx;
    379	struct veml6030_data *data = iio_priv(indio_dev);
    380
    381	if (val == 0 && val2 == 125000) {
    382		new_gain = 0x1000; /* 0x02 << 11 */
    383		gain_idx = 3;
    384	} else if (val == 0 && val2 == 250000) {
    385		new_gain = 0x1800;
    386		gain_idx = 2;
    387	} else if (val == 1 && val2 == 0) {
    388		new_gain = 0x00;
    389		gain_idx = 1;
    390	} else if (val == 2 && val2 == 0) {
    391		new_gain = 0x800;
    392		gain_idx = 0;
    393	} else {
    394		return -EINVAL;
    395	}
    396
    397	ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
    398					VEML6030_ALS_GAIN, new_gain);
    399	if (ret) {
    400		dev_err(&data->client->dev,
    401				"can't set als gain %d\n", ret);
    402		return ret;
    403	}
    404
    405	/*
    406	 * Cache currently set gain & update resolution. For every
    407	 * increase in the gain to next level, resolution is halved
    408	 * and vice-versa.
    409	 */
    410	if (data->cur_gain < gain_idx)
    411		data->cur_resolution <<= gain_idx - data->cur_gain;
    412	else if (data->cur_gain > gain_idx)
    413		data->cur_resolution >>= data->cur_gain - gain_idx;
    414
    415	data->cur_gain = gain_idx;
    416
    417	return ret;
    418}
    419
    420static int veml6030_get_als_gain(struct iio_dev *indio_dev,
    421						int *val, int *val2)
    422{
    423	int ret, reg;
    424	struct veml6030_data *data = iio_priv(indio_dev);
    425
    426	ret = regmap_read(data->regmap, VEML6030_REG_ALS_CONF, &reg);
    427	if (ret) {
    428		dev_err(&data->client->dev,
    429				"can't read als conf register %d\n", ret);
    430		return ret;
    431	}
    432
    433	switch ((reg >> 11) & 0x03) {
    434	case 0:
    435		*val = 1;
    436		*val2 = 0;
    437		break;
    438	case 1:
    439		*val = 2;
    440		*val2 = 0;
    441		break;
    442	case 2:
    443		*val = 0;
    444		*val2 = 125000;
    445		break;
    446	case 3:
    447		*val = 0;
    448		*val2 = 250000;
    449		break;
    450	default:
    451		return -EINVAL;
    452	}
    453
    454	return IIO_VAL_INT_PLUS_MICRO;
    455}
    456
    457static int veml6030_read_thresh(struct iio_dev *indio_dev,
    458						int *val, int *val2, int dir)
    459{
    460	int ret, reg;
    461	struct veml6030_data *data = iio_priv(indio_dev);
    462
    463	if (dir == IIO_EV_DIR_RISING)
    464		ret = regmap_read(data->regmap, VEML6030_REG_ALS_WH, &reg);
    465	else
    466		ret = regmap_read(data->regmap, VEML6030_REG_ALS_WL, &reg);
    467	if (ret) {
    468		dev_err(&data->client->dev,
    469				"can't read als threshold value %d\n", ret);
    470		return ret;
    471	}
    472
    473	*val = reg & 0xffff;
    474	return IIO_VAL_INT;
    475}
    476
    477static int veml6030_write_thresh(struct iio_dev *indio_dev,
    478						int val, int val2, int dir)
    479{
    480	int ret;
    481	struct veml6030_data *data = iio_priv(indio_dev);
    482
    483	if (val > 0xFFFF || val < 0 || val2)
    484		return -EINVAL;
    485
    486	if (dir == IIO_EV_DIR_RISING) {
    487		ret = regmap_write(data->regmap, VEML6030_REG_ALS_WH, val);
    488		if (ret)
    489			dev_err(&data->client->dev,
    490					"can't set high threshold %d\n", ret);
    491	} else {
    492		ret = regmap_write(data->regmap, VEML6030_REG_ALS_WL, val);
    493		if (ret)
    494			dev_err(&data->client->dev,
    495					"can't set low threshold %d\n", ret);
    496	}
    497
    498	return ret;
    499}
    500
    501/*
    502 * Provide both raw as well as light reading in lux.
    503 * light (in lux) = resolution * raw reading
    504 */
    505static int veml6030_read_raw(struct iio_dev *indio_dev,
    506			    struct iio_chan_spec const *chan, int *val,
    507			    int *val2, long mask)
    508{
    509	int ret, reg;
    510	struct veml6030_data *data = iio_priv(indio_dev);
    511	struct regmap *regmap = data->regmap;
    512	struct device *dev = &data->client->dev;
    513
    514	switch (mask) {
    515	case IIO_CHAN_INFO_RAW:
    516	case IIO_CHAN_INFO_PROCESSED:
    517		switch (chan->type) {
    518		case IIO_LIGHT:
    519			ret = regmap_read(regmap, VEML6030_REG_ALS_DATA, &reg);
    520			if (ret < 0) {
    521				dev_err(dev, "can't read als data %d\n", ret);
    522				return ret;
    523			}
    524			if (mask == IIO_CHAN_INFO_PROCESSED) {
    525				*val = (reg * data->cur_resolution) / 10000;
    526				*val2 = (reg * data->cur_resolution) % 10000;
    527				return IIO_VAL_INT_PLUS_MICRO;
    528			}
    529			*val = reg;
    530			return IIO_VAL_INT;
    531		case IIO_INTENSITY:
    532			ret = regmap_read(regmap, VEML6030_REG_WH_DATA, &reg);
    533			if (ret < 0) {
    534				dev_err(dev, "can't read white data %d\n", ret);
    535				return ret;
    536			}
    537			if (mask == IIO_CHAN_INFO_PROCESSED) {
    538				*val = (reg * data->cur_resolution) / 10000;
    539				*val2 = (reg * data->cur_resolution) % 10000;
    540				return IIO_VAL_INT_PLUS_MICRO;
    541			}
    542			*val = reg;
    543			return IIO_VAL_INT;
    544		default:
    545			return -EINVAL;
    546		}
    547	case IIO_CHAN_INFO_INT_TIME:
    548		if (chan->type == IIO_LIGHT)
    549			return veml6030_get_intgrn_tm(indio_dev, val, val2);
    550		return -EINVAL;
    551	case IIO_CHAN_INFO_SCALE:
    552		if (chan->type == IIO_LIGHT)
    553			return veml6030_get_als_gain(indio_dev, val, val2);
    554		return -EINVAL;
    555	default:
    556		return -EINVAL;
    557	}
    558}
    559
    560static int veml6030_write_raw(struct iio_dev *indio_dev,
    561				struct iio_chan_spec const *chan,
    562				int val, int val2, long mask)
    563{
    564	switch (mask) {
    565	case IIO_CHAN_INFO_INT_TIME:
    566		switch (chan->type) {
    567		case IIO_LIGHT:
    568			return veml6030_set_intgrn_tm(indio_dev, val, val2);
    569		default:
    570			return -EINVAL;
    571		}
    572	case IIO_CHAN_INFO_SCALE:
    573		switch (chan->type) {
    574		case IIO_LIGHT:
    575			return veml6030_set_als_gain(indio_dev, val, val2);
    576		default:
    577			return -EINVAL;
    578		}
    579	default:
    580		return -EINVAL;
    581	}
    582}
    583
    584static int veml6030_read_event_val(struct iio_dev *indio_dev,
    585		const struct iio_chan_spec *chan, enum iio_event_type type,
    586		enum iio_event_direction dir, enum iio_event_info info,
    587		int *val, int *val2)
    588{
    589	switch (info) {
    590	case IIO_EV_INFO_VALUE:
    591		switch (dir) {
    592		case IIO_EV_DIR_RISING:
    593		case IIO_EV_DIR_FALLING:
    594			return veml6030_read_thresh(indio_dev, val, val2, dir);
    595		default:
    596			return -EINVAL;
    597		}
    598		break;
    599	case IIO_EV_INFO_PERIOD:
    600		return veml6030_read_persistence(indio_dev, val, val2);
    601	default:
    602		return -EINVAL;
    603	}
    604}
    605
    606static int veml6030_write_event_val(struct iio_dev *indio_dev,
    607		const struct iio_chan_spec *chan, enum iio_event_type type,
    608		enum iio_event_direction dir, enum iio_event_info info,
    609		int val, int val2)
    610{
    611	switch (info) {
    612	case IIO_EV_INFO_VALUE:
    613		return veml6030_write_thresh(indio_dev, val, val2, dir);
    614	case IIO_EV_INFO_PERIOD:
    615		return veml6030_write_persistence(indio_dev, val, val2);
    616	default:
    617		return -EINVAL;
    618	}
    619}
    620
    621static int veml6030_read_interrupt_config(struct iio_dev *indio_dev,
    622		const struct iio_chan_spec *chan, enum iio_event_type type,
    623		enum iio_event_direction dir)
    624{
    625	int ret, reg;
    626	struct veml6030_data *data = iio_priv(indio_dev);
    627
    628	ret = regmap_read(data->regmap, VEML6030_REG_ALS_CONF, &reg);
    629	if (ret) {
    630		dev_err(&data->client->dev,
    631				"can't read als conf register %d\n", ret);
    632		return ret;
    633	}
    634
    635	if (reg & VEML6030_ALS_INT_EN)
    636		return 1;
    637	else
    638		return 0;
    639}
    640
    641/*
    642 * Sensor should not be measuring light when interrupt is configured.
    643 * Therefore correct sequence to configure interrupt functionality is:
    644 * shut down -> enable/disable interrupt -> power on
    645 *
    646 * state = 1 enables interrupt, state = 0 disables interrupt
    647 */
    648static int veml6030_write_interrupt_config(struct iio_dev *indio_dev,
    649		const struct iio_chan_spec *chan, enum iio_event_type type,
    650		enum iio_event_direction dir, int state)
    651{
    652	int ret;
    653	struct veml6030_data *data = iio_priv(indio_dev);
    654
    655	if (state < 0 || state > 1)
    656		return -EINVAL;
    657
    658	ret = veml6030_als_shut_down(data);
    659	if (ret < 0) {
    660		dev_err(&data->client->dev,
    661			"can't disable als to configure interrupt %d\n", ret);
    662		return ret;
    663	}
    664
    665	/* enable interrupt + power on */
    666	ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
    667			VEML6030_ALS_INT_EN | VEML6030_ALS_SD, state << 1);
    668	if (ret)
    669		dev_err(&data->client->dev,
    670			"can't enable interrupt & poweron als %d\n", ret);
    671
    672	return ret;
    673}
    674
    675static const struct iio_info veml6030_info = {
    676	.read_raw  = veml6030_read_raw,
    677	.write_raw = veml6030_write_raw,
    678	.read_event_value = veml6030_read_event_val,
    679	.write_event_value	= veml6030_write_event_val,
    680	.read_event_config = veml6030_read_interrupt_config,
    681	.write_event_config	= veml6030_write_interrupt_config,
    682	.attrs = &veml6030_attr_group,
    683	.event_attrs = &veml6030_event_attr_group,
    684};
    685
    686static const struct iio_info veml6030_info_no_irq = {
    687	.read_raw  = veml6030_read_raw,
    688	.write_raw = veml6030_write_raw,
    689	.attrs = &veml6030_attr_group,
    690};
    691
    692static irqreturn_t veml6030_event_handler(int irq, void *private)
    693{
    694	int ret, reg, evtdir;
    695	struct iio_dev *indio_dev = private;
    696	struct veml6030_data *data = iio_priv(indio_dev);
    697
    698	ret = regmap_read(data->regmap, VEML6030_REG_ALS_INT, &reg);
    699	if (ret) {
    700		dev_err(&data->client->dev,
    701				"can't read als interrupt register %d\n", ret);
    702		return IRQ_HANDLED;
    703	}
    704
    705	/* Spurious interrupt handling */
    706	if (!(reg & (VEML6030_INT_TH_HIGH | VEML6030_INT_TH_LOW)))
    707		return IRQ_NONE;
    708
    709	if (reg & VEML6030_INT_TH_HIGH)
    710		evtdir = IIO_EV_DIR_RISING;
    711	else
    712		evtdir = IIO_EV_DIR_FALLING;
    713
    714	iio_push_event(indio_dev, IIO_UNMOD_EVENT_CODE(IIO_INTENSITY,
    715					0, IIO_EV_TYPE_THRESH, evtdir),
    716					iio_get_time_ns(indio_dev));
    717
    718	return IRQ_HANDLED;
    719}
    720
    721/*
    722 * Set ALS gain to 1/8, integration time to 100 ms, PSM to mode 2,
    723 * persistence to 1 x integration time and the threshold
    724 * interrupt disabled by default. First shutdown the sensor,
    725 * update registers and then power on the sensor.
    726 */
    727static int veml6030_hw_init(struct iio_dev *indio_dev)
    728{
    729	int ret, val;
    730	struct veml6030_data *data = iio_priv(indio_dev);
    731	struct i2c_client *client = data->client;
    732
    733	ret = veml6030_als_shut_down(data);
    734	if (ret) {
    735		dev_err(&client->dev, "can't shutdown als %d\n", ret);
    736		return ret;
    737	}
    738
    739	ret = regmap_write(data->regmap, VEML6030_REG_ALS_CONF, 0x1001);
    740	if (ret) {
    741		dev_err(&client->dev, "can't setup als configs %d\n", ret);
    742		return ret;
    743	}
    744
    745	ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_PSM,
    746				 VEML6030_PSM | VEML6030_PSM_EN, 0x03);
    747	if (ret) {
    748		dev_err(&client->dev, "can't setup default PSM %d\n", ret);
    749		return ret;
    750	}
    751
    752	ret = regmap_write(data->regmap, VEML6030_REG_ALS_WH, 0xFFFF);
    753	if (ret) {
    754		dev_err(&client->dev, "can't setup high threshold %d\n", ret);
    755		return ret;
    756	}
    757
    758	ret = regmap_write(data->regmap, VEML6030_REG_ALS_WL, 0x0000);
    759	if (ret) {
    760		dev_err(&client->dev, "can't setup low threshold %d\n", ret);
    761		return ret;
    762	}
    763
    764	ret = veml6030_als_pwr_on(data);
    765	if (ret) {
    766		dev_err(&client->dev, "can't poweron als %d\n", ret);
    767		return ret;
    768	}
    769
    770	/* Wait 4 ms to let processor & oscillator start correctly */
    771	usleep_range(4000, 4002);
    772
    773	/* Clear stale interrupt status bits if any during start */
    774	ret = regmap_read(data->regmap, VEML6030_REG_ALS_INT, &val);
    775	if (ret < 0) {
    776		dev_err(&client->dev,
    777			"can't clear als interrupt status %d\n", ret);
    778		return ret;
    779	}
    780
    781	/* Cache currently active measurement parameters */
    782	data->cur_gain = 3;
    783	data->cur_resolution = 4608;
    784	data->cur_integration_time = 3;
    785
    786	return ret;
    787}
    788
    789static int veml6030_probe(struct i2c_client *client,
    790			  const struct i2c_device_id *id)
    791{
    792	int ret;
    793	struct veml6030_data *data;
    794	struct iio_dev *indio_dev;
    795	struct regmap *regmap;
    796
    797	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
    798		dev_err(&client->dev, "i2c adapter doesn't support plain i2c\n");
    799		return -EOPNOTSUPP;
    800	}
    801
    802	regmap = devm_regmap_init_i2c(client, &veml6030_regmap_config);
    803	if (IS_ERR(regmap)) {
    804		dev_err(&client->dev, "can't setup regmap\n");
    805		return PTR_ERR(regmap);
    806	}
    807
    808	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
    809	if (!indio_dev)
    810		return -ENOMEM;
    811
    812	data = iio_priv(indio_dev);
    813	i2c_set_clientdata(client, indio_dev);
    814	data->client = client;
    815	data->regmap = regmap;
    816
    817	indio_dev->name = "veml6030";
    818	indio_dev->channels = veml6030_channels;
    819	indio_dev->num_channels = ARRAY_SIZE(veml6030_channels);
    820	indio_dev->modes = INDIO_DIRECT_MODE;
    821
    822	if (client->irq) {
    823		ret = devm_request_threaded_irq(&client->dev, client->irq,
    824						NULL, veml6030_event_handler,
    825						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
    826						"veml6030", indio_dev);
    827		if (ret < 0) {
    828			dev_err(&client->dev,
    829					"irq %d request failed\n", client->irq);
    830			return ret;
    831		}
    832		indio_dev->info = &veml6030_info;
    833	} else {
    834		indio_dev->info = &veml6030_info_no_irq;
    835	}
    836
    837	ret = veml6030_hw_init(indio_dev);
    838	if (ret < 0)
    839		return ret;
    840
    841	ret = devm_add_action_or_reset(&client->dev,
    842					veml6030_als_shut_down_action, data);
    843	if (ret < 0)
    844		return ret;
    845
    846	return devm_iio_device_register(&client->dev, indio_dev);
    847}
    848
    849static int __maybe_unused veml6030_runtime_suspend(struct device *dev)
    850{
    851	int ret;
    852	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
    853	struct veml6030_data *data = iio_priv(indio_dev);
    854
    855	ret = veml6030_als_shut_down(data);
    856	if (ret < 0)
    857		dev_err(&data->client->dev, "can't suspend als %d\n", ret);
    858
    859	return ret;
    860}
    861
    862static int __maybe_unused veml6030_runtime_resume(struct device *dev)
    863{
    864	int ret;
    865	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
    866	struct veml6030_data *data = iio_priv(indio_dev);
    867
    868	ret = veml6030_als_pwr_on(data);
    869	if (ret < 0)
    870		dev_err(&data->client->dev, "can't resume als %d\n", ret);
    871
    872	return ret;
    873}
    874
    875static const struct dev_pm_ops veml6030_pm_ops = {
    876	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
    877				pm_runtime_force_resume)
    878	SET_RUNTIME_PM_OPS(veml6030_runtime_suspend,
    879				veml6030_runtime_resume, NULL)
    880};
    881
    882static const struct of_device_id veml6030_of_match[] = {
    883	{ .compatible = "vishay,veml6030" },
    884	{ }
    885};
    886MODULE_DEVICE_TABLE(of, veml6030_of_match);
    887
    888static const struct i2c_device_id veml6030_id[] = {
    889	{ "veml6030", 0 },
    890	{ }
    891};
    892MODULE_DEVICE_TABLE(i2c, veml6030_id);
    893
    894static struct i2c_driver veml6030_driver = {
    895	.driver = {
    896		.name = "veml6030",
    897		.of_match_table = veml6030_of_match,
    898		.pm = &veml6030_pm_ops,
    899	},
    900	.probe = veml6030_probe,
    901	.id_table = veml6030_id,
    902};
    903module_i2c_driver(veml6030_driver);
    904
    905MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
    906MODULE_DESCRIPTION("VEML6030 Ambient Light Sensor");
    907MODULE_LICENSE("GPL v2");