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Release 4.7 drivers/iio/light/max44000.c

/*
 * MAX44000 Ambient and Infrared Proximity Sensor
 *
 * Copyright (c) 2016, Intel Corporation.
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * Data sheet: https://datasheets.maximintegrated.com/en/ds/MAX44000.pdf
 *
 * 7-bit I2C slave address 0x4a
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/util_macros.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/acpi.h>


#define MAX44000_DRV_NAME		"max44000"

/* Registers in datasheet order */

#define MAX44000_REG_STATUS		0x00

#define MAX44000_REG_CFG_MAIN		0x01

#define MAX44000_REG_CFG_RX		0x02

#define MAX44000_REG_CFG_TX		0x03

#define MAX44000_REG_ALS_DATA_HI	0x04

#define MAX44000_REG_ALS_DATA_LO	0x05

#define MAX44000_REG_PRX_DATA		0x16

#define MAX44000_REG_ALS_UPTHR_HI	0x06

#define MAX44000_REG_ALS_UPTHR_LO	0x07

#define MAX44000_REG_ALS_LOTHR_HI	0x08

#define MAX44000_REG_ALS_LOTHR_LO	0x09

#define MAX44000_REG_PST		0x0a

#define MAX44000_REG_PRX_IND		0x0b

#define MAX44000_REG_PRX_THR		0x0c

#define MAX44000_REG_TRIM_GAIN_GREEN	0x0f

#define MAX44000_REG_TRIM_GAIN_IR	0x10

/* REG_CFG bits */

#define MAX44000_CFG_ALSINTE            0x01

#define MAX44000_CFG_PRXINTE            0x02

#define MAX44000_CFG_MASK               0x1c

#define MAX44000_CFG_MODE_SHUTDOWN      0x00

#define MAX44000_CFG_MODE_ALS_GIR       0x04

#define MAX44000_CFG_MODE_ALS_G         0x08

#define MAX44000_CFG_MODE_ALS_IR        0x0c

#define MAX44000_CFG_MODE_ALS_PRX       0x10

#define MAX44000_CFG_MODE_PRX           0x14

#define MAX44000_CFG_TRIM               0x20

/*
 * Upper 4 bits are not documented but start as 1 on powerup
 * Setting them to 0 causes proximity to misbehave so set them to 1
 */

#define MAX44000_REG_CFG_RX_DEFAULT 0xf0

/* REG_RX bits */

#define MAX44000_CFG_RX_ALSTIM_MASK	0x0c

#define MAX44000_CFG_RX_ALSTIM_SHIFT	2

#define MAX44000_CFG_RX_ALSPGA_MASK	0x03

#define MAX44000_CFG_RX_ALSPGA_SHIFT	0

/* REG_TX bits */

#define MAX44000_LED_CURRENT_MASK	0xf

#define MAX44000_LED_CURRENT_MAX	11

#define MAX44000_LED_CURRENT_DEFAULT	6


#define MAX44000_ALSDATA_OVERFLOW	0x4000


struct max44000_data {
	
struct mutex lock;
	
struct regmap *regmap;
};

/* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */

#define MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 5

/* Scale can be multiplied by up to 128x via ALSPGA for measurement gain */

static const int max44000_alspga_shift[] = {0, 2, 4, 7};

#define MAX44000_ALSPGA_MAX_SHIFT 7

/*
 * Scale can be multiplied by up to 64x via ALSTIM because of lost resolution
 *
 * This scaling factor is hidden from userspace and instead accounted for when
 * reading raw values from the device.
 *
 * This makes it possible to cleanly expose ALSPGA as IIO_CHAN_INFO_SCALE and
 * ALSTIM as IIO_CHAN_INFO_INT_TIME without the values affecting each other.
 *
 * Handling this internally is also required for buffer support because the
 * channel's scan_type can't be modified dynamically.
 */

static const int max44000_alstim_shift[] = {0, 2, 4, 6};

#define MAX44000_ALSTIM_SHIFT(alstim) (2 * (alstim))

/* Available integration times with pretty manual alignment: */

static const int max44000_int_time_avail_ns_array[] = {
	   100000000,
	    25000000,
	     6250000,
	     1562500,
};

static const char max44000_int_time_avail_str[] =
	"0.100 "
	"0.025 "
	"0.00625 "
	"0.001625";

/* Available scales (internal to ulux) with pretty manual alignment: */

static const int max44000_scale_avail_ulux_array[] = {
	    31250,
	   125000,
	   500000,
	  4000000,
};

static const char max44000_scale_avail_str[] =
	"0.03125 "
	"0.125 "
	"0.5 "
	 "4";


#define MAX44000_SCAN_INDEX_ALS 0

#define MAX44000_SCAN_INDEX_PRX 1


static const struct iio_chan_spec max44000_channels[] = {
	{
		.type = IIO_LIGHT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
					    BIT(IIO_CHAN_INFO_INT_TIME),
		.scan_index = MAX44000_SCAN_INDEX_ALS,
		.scan_type = {
			.sign		= 'u',
			.realbits	= 14,
			.storagebits	= 16,
                }
	},
	{
		.type = IIO_PROXIMITY,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.scan_index = MAX44000_SCAN_INDEX_PRX,
		.scan_type = {
			.sign		= 'u',
			.realbits	= 8,
			.storagebits	= 16,
                }
	},
	IIO_CHAN_SOFT_TIMESTAMP(2),
	{
		.type = IIO_CURRENT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
				      BIT(IIO_CHAN_INFO_SCALE),
		.extend_name = "led",
		.output = 1,
		.scan_index = -1,
        },
};


static int max44000_read_alstim(struct max44000_data *data) { unsigned int val; int ret; ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val); if (ret < 0) return ret; return (val & MAX44000_CFG_RX_ALSTIM_MASK) >> MAX44000_CFG_RX_ALSTIM_SHIFT; }

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static int max44000_write_alstim(struct max44000_data *data, int val) { return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX, MAX44000_CFG_RX_ALSTIM_MASK, val << MAX44000_CFG_RX_ALSTIM_SHIFT); }

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static int max44000_read_alspga(struct max44000_data *data) { unsigned int val; int ret; ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val); if (ret < 0) return ret; return (val & MAX44000_CFG_RX_ALSPGA_MASK) >> MAX44000_CFG_RX_ALSPGA_SHIFT; }

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static int max44000_write_alspga(struct max44000_data *data, int val) { return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX, MAX44000_CFG_RX_ALSPGA_MASK, val << MAX44000_CFG_RX_ALSPGA_SHIFT); }

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static int max44000_read_alsval(struct max44000_data *data) { u16 regval; int alstim, ret; ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI, &regval, sizeof(regval)); if (ret < 0) return ret; alstim = ret = max44000_read_alstim(data); if (ret < 0) return ret; regval = be16_to_cpu(regval); /* * Overflow is explained on datasheet page 17. * * It's a warning that either the G or IR channel has become saturated * and that the value in the register is likely incorrect. * * The recommendation is to change the scale (ALSPGA). * The driver just returns the max representable value. */ if (regval & MAX44000_ALSDATA_OVERFLOW) return 0x3FFF; return regval << MAX44000_ALSTIM_SHIFT(alstim); }

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static int max44000_write_led_current_raw(struct max44000_data *data, int val) { /* Maybe we should clamp the value instead? */ if (val < 0 || val > MAX44000_LED_CURRENT_MAX) return -ERANGE; if (val >= 8) val += 4; return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX, MAX44000_LED_CURRENT_MASK, val); }

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static int max44000_read_led_current_raw(struct max44000_data *data) { unsigned int regval; int ret; ret = regmap_read(data->regmap, MAX44000_REG_CFG_TX, &regval); if (ret < 0) return ret; regval &= MAX44000_LED_CURRENT_MASK; if (regval >= 8) regval -= 4; return regval; }

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static int max44000_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct max44000_data *data = iio_priv(indio_dev); int alstim, alspga; unsigned int regval; int ret; switch (mask) { case IIO_CHAN_INFO_RAW: switch (chan->type) { case IIO_LIGHT: mutex_lock(&data->lock); ret = max44000_read_alsval(data); mutex_unlock(&data->lock); if (ret < 0) return ret; *val = ret; return IIO_VAL_INT; case IIO_PROXIMITY: mutex_lock(&data->lock); ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, &regval); mutex_unlock(&data->lock); if (ret < 0) return ret; *val = regval; return IIO_VAL_INT; case IIO_CURRENT: mutex_lock(&data->lock); ret = max44000_read_led_current_raw(data); mutex_unlock(&data->lock); if (ret < 0) return ret; *val = ret; return IIO_VAL_INT; default: return -EINVAL; } case IIO_CHAN_INFO_SCALE: switch (chan->type) { case IIO_CURRENT: /* Output register is in 10s of miliamps */ *val = 10; return IIO_VAL_INT; case IIO_LIGHT: mutex_lock(&data->lock); alspga = ret = max44000_read_alspga(data); mutex_unlock(&data->lock); if (ret < 0) return ret; /* Avoid negative shifts */ *val = (1 << MAX44000_ALSPGA_MAX_SHIFT); *val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 + MAX44000_ALSPGA_MAX_SHIFT - max44000_alspga_shift[alspga]; return IIO_VAL_FRACTIONAL_LOG2; default: return -EINVAL; } case IIO_CHAN_INFO_INT_TIME: mutex_lock(&data->lock); alstim = ret = max44000_read_alstim(data); mutex_unlock(&data->lock); if (ret < 0) return ret; *val = 0; *val2 = max44000_int_time_avail_ns_array[alstim]; return IIO_VAL_INT_PLUS_NANO; default: return -EINVAL; } }

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static int max44000_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { struct max44000_data *data = iio_priv(indio_dev); int ret; if (mask == IIO_CHAN_INFO_RAW && chan->type == IIO_CURRENT) { mutex_lock(&data->lock); ret = max44000_write_led_current_raw(data, val); mutex_unlock(&data->lock); return ret; } else if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) { s64 valns = val * NSEC_PER_SEC + val2; int alstim = find_closest_descending(valns, max44000_int_time_avail_ns_array, ARRAY_SIZE(max44000_int_time_avail_ns_array)); mutex_lock(&data->lock); ret = max44000_write_alstim(data, alstim); mutex_unlock(&data->lock); return ret; } else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) { s64 valus = val * USEC_PER_SEC + val2; int alspga = find_closest(valus, max44000_scale_avail_ulux_array, ARRAY_SIZE(max44000_scale_avail_ulux_array)); mutex_lock(&data->lock); ret = max44000_write_alspga(data, alspga); mutex_unlock(&data->lock); return ret; } return -EINVAL; }

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static int max44000_write_raw_get_fmt(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, long mask) { if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) return IIO_VAL_INT_PLUS_NANO; else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) return IIO_VAL_INT_PLUS_MICRO; else return IIO_VAL_INT; }

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static IIO_CONST_ATTR(illuminance_integration_time_available, max44000_int_time_avail_str); static IIO_CONST_ATTR(illuminance_scale_available, max44000_scale_avail_str); static struct attribute *max44000_attributes[] = { &iio_const_attr_illuminance_integration_time_available.dev_attr.attr, &iio_const_attr_illuminance_scale_available.dev_attr.attr, NULL }; static const struct attribute_group max44000_attribute_group = { .attrs = max44000_attributes, }; static const struct iio_info max44000_info = { .driver_module = THIS_MODULE, .read_raw = max44000_read_raw, .write_raw = max44000_write_raw, .write_raw_get_fmt = max44000_write_raw_get_fmt, .attrs = &max44000_attribute_group, };
static bool max44000_readable_reg(struct device *dev, unsigned int reg) { switch (reg) { case MAX44000_REG_STATUS: case MAX44000_REG_CFG_MAIN: case MAX44000_REG_CFG_RX: case MAX44000_REG_CFG_TX: case MAX44000_REG_ALS_DATA_HI: case MAX44000_REG_ALS_DATA_LO: case MAX44000_REG_PRX_DATA: case MAX44000_REG_ALS_UPTHR_HI: case MAX44000_REG_ALS_UPTHR_LO: case MAX44000_REG_ALS_LOTHR_HI: case MAX44000_REG_ALS_LOTHR_LO: case MAX44000_REG_PST: case MAX44000_REG_PRX_IND: case MAX44000_REG_PRX_THR: case MAX44000_REG_TRIM_GAIN_GREEN: case MAX44000_REG_TRIM_GAIN_IR: return true; default: return false; } }

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static bool max44000_writeable_reg(struct device *dev, unsigned int reg) { switch (reg) { case MAX44000_REG_CFG_MAIN: case MAX44000_REG_CFG_RX: case MAX44000_REG_CFG_TX: case MAX44000_REG_ALS_UPTHR_HI: case MAX44000_REG_ALS_UPTHR_LO: case MAX44000_REG_ALS_LOTHR_HI: case MAX44000_REG_ALS_LOTHR_LO: case MAX44000_REG_PST: case MAX44000_REG_PRX_IND: case MAX44000_REG_PRX_THR: case MAX44000_REG_TRIM_GAIN_GREEN: case MAX44000_REG_TRIM_GAIN_IR: return true; default: return false; } }

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static bool max44000_volatile_reg(struct device *dev, unsigned int reg) { switch (reg) { case MAX44000_REG_STATUS: case MAX44000_REG_ALS_DATA_HI: case MAX44000_REG_ALS_DATA_LO: case MAX44000_REG_PRX_DATA: return true; default: return false; } }

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static bool max44000_precious_reg(struct device *dev, unsigned int reg) { return reg == MAX44000_REG_STATUS; }

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static const struct regmap_config max44000_regmap_config = { .reg_bits = 8, .val_bits = 8, .max_register = MAX44000_REG_PRX_DATA, .readable_reg = max44000_readable_reg, .writeable_reg = max44000_writeable_reg, .volatile_reg = max44000_volatile_reg, .precious_reg = max44000_precious_reg, .use_single_rw = 1, .cache_type = REGCACHE_RBTREE, };
static irqreturn_t max44000_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct max44000_data *data = iio_priv(indio_dev); u16 buf[8]; /* 2x u16 + padding + 8 bytes timestamp */ int index = 0; unsigned int regval; int ret; mutex_lock(&data->lock); if (test_bit(MAX44000_SCAN_INDEX_ALS, indio_dev->active_scan_mask)) { ret = max44000_read_alsval(data); if (ret < 0) goto out_unlock; buf[index++] = ret; } if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) { ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, &regval); if (ret < 0) goto out_unlock; buf[index] = regval; } mutex_unlock(&data->lock); iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns()); iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; out_unlock: mutex_unlock(&data->lock); iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; }

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static int max44000_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct max44000_data *data; struct iio_dev *indio_dev; int ret, reg; indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); data->regmap = devm_regmap_init_i2c(client, &max44000_regmap_config); if (IS_ERR(data->regmap)) { dev_err(&client->dev, "regmap_init failed!\n"); return PTR_ERR(data->regmap); } i2c_set_clientdata(client, indio_dev); mutex_init(&data->lock); indio_dev->dev.parent = &client->dev; indio_dev->info = &max44000_info; indio_dev->name = MAX44000_DRV_NAME; indio_dev->channels = max44000_channels; indio_dev->num_channels = ARRAY_SIZE(max44000_channels); /* * The device doesn't have a reset function so we just clear some * important bits at probe time to ensure sane operation. * * Since we don't support interrupts/events the threshold values are * not important. We also don't touch trim values. */ /* Reset ALS scaling bits */ ret = regmap_write(data->regmap, MAX44000_REG_CFG_RX, MAX44000_REG_CFG_RX_DEFAULT); if (ret < 0) { dev_err(&client->dev, "failed to write default CFG_RX: %d\n", ret); return ret; } /* * By default the LED pulse used for the proximity sensor is disabled. * Set a middle value so that we get some sort of valid data by default. */ ret = max44000_write_led_current_raw(data, MAX44000_LED_CURRENT_DEFAULT); if (ret < 0) { dev_err(&client->dev, "failed to write init config: %d\n", ret); return ret; } /* Reset CFG bits to ALS_PRX mode which allows easy reading of both values. */ reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX; ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg); if (ret < 0) { dev_err(&client->dev, "failed to write init config: %d\n", ret); return ret; } /* Read status at least once to clear any stale interrupt bits. */ ret = regmap_read(data->regmap, MAX44000_REG_STATUS, &reg); if (ret < 0) { dev_err(&client->dev, "failed to read init status: %d\n", ret); return ret; } ret = iio_triggered_buffer_setup(indio_dev, NULL, max44000_trigger_handler, NULL); if (ret < 0) { dev_err(&client->dev, "iio triggered buffer setup failed\n"); return ret; } return iio_device_register(indio_dev); }

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static int max44000_remove(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); iio_device_unregister(indio_dev); iio_triggered_buffer_cleanup(indio_dev); return 0; }

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static const struct i2c_device_id max44000_id[] = { {"max44000", 0}, { } }; MODULE_DEVICE_TABLE(i2c, max44000_id); #ifdef CONFIG_ACPI static const struct acpi_device_id max44000_acpi_match[] = { {"MAX44000", 0}, { } }; MODULE_DEVICE_TABLE(acpi, max44000_acpi_match); #endif static struct i2c_driver max44000_driver = { .driver = { .name = MAX44000_DRV_NAME, .acpi_match_table = ACPI_PTR(max44000_acpi_match), }, .probe = max44000_probe, .remove = max44000_remove, .id_table = max44000_id, }; module_i2c_driver(max44000_driver); MODULE_AUTHOR("Crestez Dan Leonard <leonard.crestez@intel.com>"); MODULE_DESCRIPTION("MAX44000 Ambient and Infrared Proximity Sensor"); MODULE_LICENSE("GPL v2");

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