--- /dev/null
+/*
+ * Copyright (c) 2014 Intel Corporation
+ *
+ * Driver for Bosch Sensortec BMP280 digital pressure sensor.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#define pr_fmt(fmt) "bmp280: " fmt
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/regmap.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define BMP280_REG_TEMP_XLSB 0xFC
+#define BMP280_REG_TEMP_LSB 0xFB
+#define BMP280_REG_TEMP_MSB 0xFA
+#define BMP280_REG_PRESS_XLSB 0xF9
+#define BMP280_REG_PRESS_LSB 0xF8
+#define BMP280_REG_PRESS_MSB 0xF7
+
+#define BMP280_REG_CONFIG 0xF5
+#define BMP280_REG_CTRL_MEAS 0xF4
+#define BMP280_REG_STATUS 0xF3
+#define BMP280_REG_RESET 0xE0
+#define BMP280_REG_ID 0xD0
+
+#define BMP280_REG_COMP_TEMP_START 0x88
+#define BMP280_COMP_TEMP_REG_COUNT 6
+
+#define BMP280_REG_COMP_PRESS_START 0x8E
+#define BMP280_COMP_PRESS_REG_COUNT 18
+
+#define BMP280_FILTER_MASK (BIT(4) | BIT(3) | BIT(2))
+#define BMP280_FILTER_OFF 0
+#define BMP280_FILTER_2X BIT(2)
+#define BMP280_FILTER_4X BIT(3)
+#define BMP280_FILTER_8X (BIT(3) | BIT(2))
+#define BMP280_FILTER_16X BIT(4)
+
+#define BMP280_OSRS_TEMP_MASK (BIT(7) | BIT(6) | BIT(5))
+#define BMP280_OSRS_TEMP_SKIP 0
+#define BMP280_OSRS_TEMP_1X BIT(5)
+#define BMP280_OSRS_TEMP_2X BIT(6)
+#define BMP280_OSRS_TEMP_4X (BIT(6) | BIT(5))
+#define BMP280_OSRS_TEMP_8X BIT(7)
+#define BMP280_OSRS_TEMP_16X (BIT(7) | BIT(5))
+
+#define BMP280_OSRS_PRESS_MASK (BIT(4) | BIT(3) | BIT(2))
+#define BMP280_OSRS_PRESS_SKIP 0
+#define BMP280_OSRS_PRESS_1X BIT(2)
+#define BMP280_OSRS_PRESS_2X BIT(3)
+#define BMP280_OSRS_PRESS_4X (BIT(3) | BIT(2))
+#define BMP280_OSRS_PRESS_8X BIT(4)
+#define BMP280_OSRS_PRESS_16X (BIT(4) | BIT(2))
+
+#define BMP280_MODE_MASK (BIT(1) | BIT(0))
+#define BMP280_MODE_SLEEP 0
+#define BMP280_MODE_FORCED BIT(0)
+#define BMP280_MODE_NORMAL (BIT(1) | BIT(0))
+
+#define BMP280_CHIP_ID 0x58
+#define BMP280_SOFT_RESET_VAL 0xB6
+
+struct bmp280_data {
+ struct i2c_client *client;
+ struct mutex lock;
+ struct regmap *regmap;
+
+ /*
+ * Carryover value from temperature conversion, used in pressure
+ * calculation.
+ */
+ s32 t_fine;
+};
+
+/* Compensation parameters. */
+struct bmp280_comp_temp {
+ u16 dig_t1;
+ s16 dig_t2, dig_t3;
+};
+
+struct bmp280_comp_press {
+ u16 dig_p1;
+ s16 dig_p2, dig_p3, dig_p4, dig_p5, dig_p6, dig_p7, dig_p8, dig_p9;
+};
+
+static const struct iio_chan_spec bmp280_channels[] = {
+ {
+ .type = IIO_PRESSURE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ },
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ },
+};
+
+static bool bmp280_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case BMP280_REG_CONFIG:
+ case BMP280_REG_CTRL_MEAS:
+ case BMP280_REG_RESET:
+ return true;
+ default:
+ return false;
+ };
+}
+
+static bool bmp280_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case BMP280_REG_TEMP_XLSB:
+ case BMP280_REG_TEMP_LSB:
+ case BMP280_REG_TEMP_MSB:
+ case BMP280_REG_PRESS_XLSB:
+ case BMP280_REG_PRESS_LSB:
+ case BMP280_REG_PRESS_MSB:
+ case BMP280_REG_STATUS:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static const struct regmap_config bmp280_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+
+ .max_register = BMP280_REG_TEMP_XLSB,
+ .cache_type = REGCACHE_RBTREE,
+
+ .writeable_reg = bmp280_is_writeable_reg,
+ .volatile_reg = bmp280_is_volatile_reg,
+};
+
+static int bmp280_read_compensation_temp(struct bmp280_data *data,
+ struct bmp280_comp_temp *comp)
+{
+ int ret;
+ __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2];
+
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START,
+ buf, BMP280_COMP_TEMP_REG_COUNT);
+ if (ret < 0) {
+ dev_err(&data->client->dev,
+ "failed to read temperature calibration parameters\n");
+ return ret;
+ }
+
+ comp->dig_t1 = (u16) le16_to_cpu(buf[0]);
+ comp->dig_t2 = (s16) le16_to_cpu(buf[1]);
+ comp->dig_t3 = (s16) le16_to_cpu(buf[2]);
+
+ return 0;
+}
+
+static int bmp280_read_compensation_press(struct bmp280_data *data,
+ struct bmp280_comp_press *comp)
+{
+ int ret;
+ __le16 buf[BMP280_COMP_PRESS_REG_COUNT / 2];
+
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START,
+ buf, BMP280_COMP_PRESS_REG_COUNT);
+ if (ret < 0) {
+ dev_err(&data->client->dev,
+ "failed to read pressure calibration parameters\n");
+ return ret;
+ }
+
+ comp->dig_p1 = (s16) le16_to_cpu(buf[0]);
+ comp->dig_p2 = (u16) le16_to_cpu(buf[1]);
+ comp->dig_p3 = (u16) le16_to_cpu(buf[2]);
+ comp->dig_p4 = (u16) le16_to_cpu(buf[3]);
+ comp->dig_p5 = (u16) le16_to_cpu(buf[4]);
+ comp->dig_p6 = (u16) le16_to_cpu(buf[5]);
+ comp->dig_p7 = (u16) le16_to_cpu(buf[6]);
+ comp->dig_p8 = (u16) le16_to_cpu(buf[7]);
+ comp->dig_p9 = (u16) le16_to_cpu(buf[8]);
+
+ return 0;
+}
+
+/*
+ * Returns temperature in DegC, resolution is 0.01 DegC. Output value of
+ * "5123" equals 51.23 DegC. t_fine carries fine temperature as global
+ * value.
+ *
+ * Taken from datasheet, Section 3.11.3, "Compensation formula".
+ */
+static s32 bmp280_compensate_temp(struct bmp280_data *data,
+ struct bmp280_comp_temp *comp,
+ s32 adc_temp)
+{
+ s32 var1, var2, t;
+
+ var1 = (((adc_temp >> 3) - ((s32) comp->dig_t1 << 1)) *
+ ((s32) comp->dig_t2)) >> 11;
+ var2 = (((((adc_temp >> 4) - ((s32) comp->dig_t1)) *
+ ((adc_temp >> 4) - ((s32) comp->dig_t1))) >> 12) *
+ ((s32) comp->dig_t3)) >> 14;
+
+ data->t_fine = var1 + var2;
+ t = (data->t_fine * 5 + 128) >> 8;
+
+ return t;
+}
+
+/*
+ * Returns pressure in Pa as unsigned 32 bit integer in Q24.8 format (24
+ * integer bits and 8 fractional bits). Output value of "24674867"
+ * represents 24674867/256 = 96386.2 Pa = 963.862 hPa
+ *
+ * Taken from datasheet, Section 3.11.3, "Compensation formula".
+ */
+static u32 bmp280_compensate_press(struct bmp280_data *data,
+ struct bmp280_comp_press *comp,
+ s32 adc_press)
+{
+ s64 var1, var2, p;
+
+ var1 = ((s64) data->t_fine) - 128000;
+ var2 = var1 * var1 * (s64) comp->dig_p6;
+ var2 = var2 + ((var1 * (s64) comp->dig_p5) << 17);
+ var2 = var2 + (((s64) comp->dig_p4) << 35);
+ var1 = ((var1 * var1 * (s64) comp->dig_p3) >> 8) +
+ ((var1 * (s64) comp->dig_p2) << 12);
+ var1 = (((((s64) 1) << 47) + var1)) * ((s64) comp->dig_p1) >> 33;
+
+ if (var1 == 0)
+ return 0;
+
+ p = ((((s64) 1048576 - adc_press) << 31) - var2) * 3125;
+ do_div(p, var1);
+ var1 = (((s64) comp->dig_p9) * (p >> 13) * (p >> 13)) >> 25;
+ var2 = (((s64) comp->dig_p8) * p) >> 19;
+ p = ((p + var1 + var2) >> 8) + (((s64) comp->dig_p7) << 4);
+
+ return (u32) p;
+}
+
+static int bmp280_read_temp(struct bmp280_data *data,
+ int *val)
+{
+ int ret;
+ __be32 tmp = 0;
+ s32 adc_temp, comp_temp;
+ struct bmp280_comp_temp comp;
+
+ ret = bmp280_read_compensation_temp(data, &comp);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB,
+ (u8 *) &tmp, 3);
+ if (ret < 0) {
+ dev_err(&data->client->dev, "failed to read temperature\n");
+ return ret;
+ }
+
+ adc_temp = be32_to_cpu(tmp) >> 12;
+ comp_temp = bmp280_compensate_temp(data, &comp, adc_temp);
+
+ /*
+ * val might be NULL if we're called by the read_press routine,
+ * who only cares about the carry over t_fine value.
+ */
+ if (val) {
+ *val = comp_temp * 10;
+ return IIO_VAL_INT;
+ }
+
+ return 0;
+}
+
+static int bmp280_read_press(struct bmp280_data *data,
+ int *val, int *val2)
+{
+ int ret;
+ __be32 tmp = 0;
+ s32 adc_press;
+ u32 comp_press;
+ struct bmp280_comp_press comp;
+
+ ret = bmp280_read_compensation_press(data, &comp);
+ if (ret < 0)
+ return ret;
+
+ /* Read and compensate temperature so we get a reading of t_fine. */
+ ret = bmp280_read_temp(data, NULL);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_PRESS_MSB,
+ (u8 *) &tmp, 3);
+ if (ret < 0) {
+ dev_err(&data->client->dev, "failed to read pressure\n");
+ return ret;
+ }
+
+ adc_press = be32_to_cpu(tmp) >> 12;
+ comp_press = bmp280_compensate_press(data, &comp, adc_press);
+
+ *val = comp_press / 256000;
+ *val2 = comp_press * 1000000 / 256000;
+
+ return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int bmp280_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int ret;
+ struct bmp280_data *data = iio_priv(indio_dev);
+
+ mutex_lock(&data->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_PROCESSED:
+ switch (chan->type) {
+ case IIO_PRESSURE:
+ ret = bmp280_read_press(data, val, val2);
+ break;
+ case IIO_TEMP:
+ ret = bmp280_read_temp(data, val);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static const struct iio_info bmp280_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = &bmp280_read_raw,
+};
+
+static int bmp280_chip_init(struct bmp280_data *data)
+{
+ int ret;
+
+ ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_MEAS,
+ BMP280_OSRS_TEMP_MASK |
+ BMP280_OSRS_PRESS_MASK |
+ BMP280_MODE_MASK,
+ BMP280_OSRS_TEMP_2X |
+ BMP280_OSRS_PRESS_16X |
+ BMP280_MODE_NORMAL);
+ if (ret < 0) {
+ dev_err(&data->client->dev,
+ "failed to write config register\n");
+ return ret;
+ }
+
+ ret = regmap_update_bits(data->regmap, BMP280_REG_CONFIG,
+ BMP280_FILTER_MASK,
+ BMP280_FILTER_4X);
+ if (ret < 0) {
+ dev_err(&data->client->dev,
+ "failed to write config register\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+static int bmp280_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct iio_dev *indio_dev;
+ struct bmp280_data *data;
+ unsigned int chip_id;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, indio_dev);
+ data = iio_priv(indio_dev);
+ mutex_init(&data->lock);
+ data->client = client;
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->name = id->name;
+ indio_dev->channels = bmp280_channels;
+ indio_dev->num_channels = ARRAY_SIZE(bmp280_channels);
+ indio_dev->info = &bmp280_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ data->regmap = devm_regmap_init_i2c(client, &bmp280_regmap_config);
+ if (IS_ERR(data->regmap)) {
+ dev_err(&client->dev, "failed to allocate register map\n");
+ return PTR_ERR(data->regmap);
+ }
+
+ ret = regmap_read(data->regmap, BMP280_REG_ID, &chip_id);
+ if (ret < 0)
+ return ret;
+ if (chip_id != BMP280_CHIP_ID) {
+ dev_err(&client->dev, "bad chip id. expected %x got %x\n",
+ BMP280_CHIP_ID, chip_id);
+ return -EINVAL;
+ }
+
+ ret = bmp280_chip_init(data);
+ if (ret < 0)
+ return ret;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct acpi_device_id bmp280_acpi_match[] = {
+ {"BMP0280", 0},
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, bmp280_acpi_match);
+
+static const struct i2c_device_id bmp280_id[] = {
+ {"bmp280", 0},
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, bmp280_id);
+
+static struct i2c_driver bmp280_driver = {
+ .driver = {
+ .name = "bmp280",
+ .acpi_match_table = ACPI_PTR(bmp280_acpi_match),
+ },
+ .probe = bmp280_probe,
+ .id_table = bmp280_id,
+};
+module_i2c_driver(bmp280_driver);
+
+MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@intel.com>");
+MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP280 pressure and temperature sensor");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-starfive.git / commitdiff