diff options
Diffstat (limited to 'drivers/iio/light/max44000.c')
| -rw-r--r-- | drivers/iio/light/max44000.c | 643 |
1 files changed, 643 insertions, 0 deletions
diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c new file mode 100644 index 000000000..7d2b3d065 --- /dev/null +++ b/drivers/iio/light/max44000.c @@ -0,0 +1,643 @@ +/* + * 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; + /* Ensure naturally aligned timestamp */ + struct { + u16 channels[2]; + s64 ts __aligned(8); + } scan; +}; + +/* 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 " + "0.0015625"; + +/* 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; +} + +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); +} + +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; +} + +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); +} + +static int max44000_read_alsval(struct max44000_data *data) +{ + u16 regval; + __be16 val; + int alstim, ret; + + ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI, + &val, sizeof(val)); + if (ret < 0) + return ret; + alstim = ret = max44000_read_alstim(data); + if (ret < 0) + return ret; + + regval = be16_to_cpu(val); + + /* + * 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); +} + +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); +} + +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, ®val); + if (ret < 0) + return ret; + regval &= MAX44000_LED_CURRENT_MASK; + if (regval >= 8) + regval -= 4; + return regval; +} + +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, ®val); + 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; + } +} + +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; +} + +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; +} + +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 = { + .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; + } +} + +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; + } +} + +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; + } +} + +static bool max44000_precious_reg(struct device *dev, unsigned int reg) +{ + return reg == MAX44000_REG_STATUS; +} + +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); + 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; + data->scan.channels[index++] = ret; + } + if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) { + ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val); + if (ret < 0) + goto out_unlock; + data->scan.channels[index] = regval; + } + mutex_unlock(&data->lock); + + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, + iio_get_time_ns(indio_dev)); + 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; +} + +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, ®); + 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); +} + +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; +} + +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"); |