// SPDX-License-Identifier: GPL-2.0+ /* * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor * * Copyright (C) 2015, 2018 * Author: Matt Ranostay <matt.ranostay@konsulko.com> * * TODO: enable pulse length controls via device tree properties */ #include <linux/module.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/irq.h> #include <linux/i2c.h> #include <linux/mutex.h> #include <linux/property.h> #include <linux/regmap.h> #include <linux/iio/iio.h> #include <linux/iio/buffer.h> #include <linux/iio/kfifo_buf.h> #define MAX30100_REGMAP_NAME "max30100_regmap" #define MAX30100_DRV_NAME "max30100" #define MAX30100_REG_INT_STATUS 0x00 #define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0) #define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4) #define MAX30100_REG_INT_STATUS_HR_RDY BIT(5) #define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7) #define MAX30100_REG_INT_ENABLE 0x01 #define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0) #define MAX30100_REG_INT_ENABLE_HR_EN BIT(1) #define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3) #define MAX30100_REG_INT_ENABLE_MASK 0xf0 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4 #define MAX30100_REG_FIFO_WR_PTR 0x02 #define MAX30100_REG_FIFO_OVR_CTR 0x03 #define MAX30100_REG_FIFO_RD_PTR 0x04 #define MAX30100_REG_FIFO_DATA 0x05 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4 #define MAX30100_REG_MODE_CONFIG 0x06 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0) #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1) #define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03 #define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3) #define MAX30100_REG_MODE_CONFIG_PWR BIT(7) #define MAX30100_REG_SPO2_CONFIG 0x07 #define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2) #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6) #define MAX30100_REG_SPO2_CONFIG_1600US 0x3 #define MAX30100_REG_LED_CONFIG 0x09 #define MAX30100_REG_LED_CONFIG_LED_MASK 0x0f #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4 #define MAX30100_REG_LED_CONFIG_24MA 0x07 #define MAX30100_REG_LED_CONFIG_50MA 0x0f #define MAX30100_REG_TEMP_INTEGER 0x16 #define MAX30100_REG_TEMP_FRACTION 0x17 struct max30100_data { struct i2c_client *client; struct iio_dev *indio_dev; struct mutex lock; struct regmap *regmap; __be16 buffer[2]; /* 2 16-bit channels */ }; static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg) { switch (reg) { case MAX30100_REG_INT_STATUS: case MAX30100_REG_MODE_CONFIG: case MAX30100_REG_FIFO_WR_PTR: case MAX30100_REG_FIFO_OVR_CTR: case MAX30100_REG_FIFO_RD_PTR: case MAX30100_REG_FIFO_DATA: case MAX30100_REG_TEMP_INTEGER: case MAX30100_REG_TEMP_FRACTION: return true; default: return false; } } static const struct regmap_config max30100_regmap_config = { .name = MAX30100_REGMAP_NAME, .reg_bits = 8, .val_bits = 8, .max_register = MAX30100_REG_TEMP_FRACTION, .cache_type = REGCACHE_FLAT, .volatile_reg = max30100_is_volatile_reg, }; static const unsigned int max30100_led_current_mapping[] = { 4400, 7600, 11000, 14200, 17400, 20800, 24000, 27100, 30600, 33800, 37000, 40200, 43600, 46800, 50000 }; static const unsigned long max30100_scan_masks[] = {0x3, 0}; static const struct iio_chan_spec max30100_channels[] = { { .type = IIO_INTENSITY, .channel2 = IIO_MOD_LIGHT_IR, .modified = 1, .scan_index = 0, .scan_type = { .sign = 'u', .realbits = 16, .storagebits = 16, .endianness = IIO_BE, }, }, { .type = IIO_INTENSITY, .channel2 = IIO_MOD_LIGHT_RED, .modified = 1, .scan_index = 1, .scan_type = { .sign = 'u', .realbits = 16, .storagebits = 16, .endianness = IIO_BE, }, }, { .type = IIO_TEMP, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), .scan_index = -1, }, }; static int max30100_set_powermode(struct max30100_data *data, bool state) { return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, MAX30100_REG_MODE_CONFIG_PWR, state ? 0 : MAX30100_REG_MODE_CONFIG_PWR); } static int max30100_clear_fifo(struct max30100_data *data) { int ret; ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0); if (ret) return ret; ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0); if (ret) return ret; return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0); } static int max30100_buffer_postenable(struct iio_dev *indio_dev) { struct max30100_data *data = iio_priv(indio_dev); int ret; ret = max30100_set_powermode(data, true); if (ret) return ret; return max30100_clear_fifo(data); } static int max30100_buffer_predisable(struct iio_dev *indio_dev) { struct max30100_data *data = iio_priv(indio_dev); return max30100_set_powermode(data, false); } static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = { .postenable = max30100_buffer_postenable, .predisable = max30100_buffer_predisable, }; static inline int max30100_fifo_count(struct max30100_data *data) { unsigned int val; int ret; ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val); if (ret) return ret; /* FIFO is almost full */ if (val & MAX30100_REG_INT_STATUS_FIFO_RDY) return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1; return 0; } static int max30100_read_measurement(struct max30100_data *data) { int ret; ret = i2c_smbus_read_i2c_block_data(data->client, MAX30100_REG_FIFO_DATA, MAX30100_REG_FIFO_DATA_ENTRY_LEN, (u8 *) &data->buffer); return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret; } static irqreturn_t max30100_interrupt_handler(int irq, void *private) { struct iio_dev *indio_dev = private; struct max30100_data *data = iio_priv(indio_dev); int ret, cnt = 0; mutex_lock(&data->lock); while (cnt || (cnt = max30100_fifo_count(data)) > 0) { ret = max30100_read_measurement(data); if (ret) break; iio_push_to_buffers(data->indio_dev, data->buffer); cnt--; } mutex_unlock(&data->lock); return IRQ_HANDLED; } static int max30100_get_current_idx(unsigned int val, int *reg) { int idx; /* LED turned off */ if (val == 0) { *reg = 0; return 0; } for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) { if (max30100_led_current_mapping[idx] == val) { *reg = idx + 1; return 0; } } return -EINVAL; } static int max30100_led_init(struct max30100_data *data) { struct device *dev = &data->client->dev; unsigned int val[2]; int reg, ret; ret = device_property_read_u32_array(dev, "maxim,led-current-microamp", (unsigned int *) &val, 2); if (ret) { /* Default to 24 mA RED LED, 50 mA IR LED */ reg = (MAX30100_REG_LED_CONFIG_24MA << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) | MAX30100_REG_LED_CONFIG_50MA; dev_warn(dev, "no led-current-microamp set"); return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg); } /* RED LED current */ ret = max30100_get_current_idx(val[0], ®); if (ret) { dev_err(dev, "invalid RED current setting %d", val[0]); return ret; } ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, MAX30100_REG_LED_CONFIG_LED_MASK << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT, reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT); if (ret) return ret; /* IR LED current */ ret = max30100_get_current_idx(val[1], ®); if (ret) { dev_err(dev, "invalid IR current setting %d", val[1]); return ret; } return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, MAX30100_REG_LED_CONFIG_LED_MASK, reg); } static int max30100_chip_init(struct max30100_data *data) { int ret; /* setup LED current settings */ ret = max30100_led_init(data); if (ret) return ret; /* enable hi-res SPO2 readings at 100Hz */ ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG, MAX30100_REG_SPO2_CONFIG_HI_RES_EN | MAX30100_REG_SPO2_CONFIG_100HZ); if (ret) return ret; /* enable SPO2 mode */ ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, MAX30100_REG_MODE_CONFIG_MODE_MASK, MAX30100_REG_MODE_CONFIG_MODE_HR_EN | MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN); if (ret) return ret; /* enable FIFO interrupt */ return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE, MAX30100_REG_INT_ENABLE_MASK, MAX30100_REG_INT_ENABLE_FIFO_EN << MAX30100_REG_INT_ENABLE_MASK_SHIFT); } static int max30100_read_temp(struct max30100_data *data, int *val) { int ret; unsigned int reg; ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®); if (ret < 0) return ret; *val = reg << 4; ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®); if (ret < 0) return ret; *val |= reg & 0xf; *val = sign_extend32(*val, 11); return 0; } static int max30100_get_temp(struct max30100_data *data, int *val) { int ret; /* start acquisition */ ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, MAX30100_REG_MODE_CONFIG_TEMP_EN, MAX30100_REG_MODE_CONFIG_TEMP_EN); if (ret) return ret; msleep(35); return max30100_read_temp(data, val); } static int max30100_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct max30100_data *data = iio_priv(indio_dev); int ret = -EINVAL; switch (mask) { case IIO_CHAN_INFO_RAW: /* * Temperature reading can only be acquired while engine * is running */ if (iio_device_claim_buffer_mode(indio_dev)) { /* * Replacing -EBUSY or other error code * returned by iio_device_claim_buffer_mode() * because user space may rely on the current * one. */ ret = -EAGAIN; } else { ret = max30100_get_temp(data, val); if (!ret) ret = IIO_VAL_INT; iio_device_release_buffer_mode(indio_dev); } break; case IIO_CHAN_INFO_SCALE: *val = 1; /* 0.0625 */ *val2 = 16; ret = IIO_VAL_FRACTIONAL; break; } return ret; } static const struct iio_info max30100_info = { .read_raw = max30100_read_raw, }; static int max30100_probe(struct i2c_client *client) { struct max30100_data *data; struct iio_dev *indio_dev; int ret; indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; indio_dev->name = MAX30100_DRV_NAME; indio_dev->channels = max30100_channels; indio_dev->info = &max30100_info; indio_dev->num_channels = ARRAY_SIZE(max30100_channels); indio_dev->available_scan_masks = max30100_scan_masks; indio_dev->modes = INDIO_DIRECT_MODE; ret = devm_iio_kfifo_buffer_setup(&client->dev, indio_dev, &max30100_buffer_setup_ops); if (ret) return ret; data = iio_priv(indio_dev); data->indio_dev = indio_dev; data->client = client; mutex_init(&data->lock); i2c_set_clientdata(client, indio_dev); data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config); if (IS_ERR(data->regmap)) { dev_err(&client->dev, "regmap initialization failed.\n"); return PTR_ERR(data->regmap); } max30100_set_powermode(data, false); ret = max30100_chip_init(data); if (ret) return ret; if (client->irq <= 0) { dev_err(&client->dev, "no valid irq defined\n"); return -EINVAL; } ret = devm_request_threaded_irq(&client->dev, client->irq, NULL, max30100_interrupt_handler, IRQF_TRIGGER_FALLING | IRQF_ONESHOT, "max30100_irq", indio_dev); if (ret) { dev_err(&client->dev, "request irq (%d) failed\n", client->irq); return ret; } return iio_device_register(indio_dev); } static void max30100_remove(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); struct max30100_data *data = iio_priv(indio_dev); iio_device_unregister(indio_dev); max30100_set_powermode(data, false); } static const struct i2c_device_id max30100_id[] = { { "max30100", 0 }, {} }; MODULE_DEVICE_TABLE(i2c, max30100_id); static const struct of_device_id max30100_dt_ids[] = { { .compatible = "maxim,max30100" }, { } }; MODULE_DEVICE_TABLE(of, max30100_dt_ids); static struct i2c_driver max30100_driver = { .driver = { .name = MAX30100_DRV_NAME, .of_match_table = max30100_dt_ids, }, .probe = max30100_probe, .remove = max30100_remove, .id_table = max30100_id, }; module_i2c_driver(max30100_driver); MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>"); MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor"); MODULE_LICENSE("GPL");