diff options
Diffstat (limited to 'drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c')
| -rw-r--r-- | drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c new file mode 100644 index 000000000..7327e5723 --- /dev/null +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 TDK-InvenSense, Inc. + */ + +#include <linux/kernel.h> +#include <linux/device.h> +#include <linux/regmap.h> +#include <linux/delay.h> + +#include "inv_mpu_aux.h" +#include "inv_mpu_iio.h" + +/* + * i2c master auxiliary bus transfer function. + * Requires the i2c operations to be correctly setup before. + */ +static int inv_mpu_i2c_master_xfer(const struct inv_mpu6050_state *st) +{ + /* use 50hz frequency for xfer */ + const unsigned int freq = 50; + const unsigned int period_ms = 1000 / freq; + uint8_t d; + unsigned int user_ctrl; + int ret; + + /* set sample rate */ + d = INV_MPU6050_FIFO_RATE_TO_DIVIDER(freq); + ret = regmap_write(st->map, st->reg->sample_rate_div, d); + if (ret) + return ret; + + /* start i2c master */ + user_ctrl = st->chip_config.user_ctrl | INV_MPU6050_BIT_I2C_MST_EN; + ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl); + if (ret) + goto error_restore_rate; + + /* wait for xfer: 1 period + half-period margin */ + msleep(period_ms + period_ms / 2); + + /* stop i2c master */ + user_ctrl = st->chip_config.user_ctrl; + ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl); + if (ret) + goto error_stop_i2c; + + /* restore sample rate */ + d = st->chip_config.divider; + ret = regmap_write(st->map, st->reg->sample_rate_div, d); + if (ret) + goto error_restore_rate; + + return 0; + +error_stop_i2c: + regmap_write(st->map, st->reg->user_ctrl, st->chip_config.user_ctrl); +error_restore_rate: + regmap_write(st->map, st->reg->sample_rate_div, st->chip_config.divider); + return ret; +} + +/** + * inv_mpu_aux_init() - init i2c auxiliary bus + * @st: driver internal state + * + * Returns 0 on success, a negative error code otherwise. + */ +int inv_mpu_aux_init(const struct inv_mpu6050_state *st) +{ + unsigned int val; + int ret; + + /* configure i2c master */ + val = INV_MPU6050_BITS_I2C_MST_CLK_400KHZ | + INV_MPU6050_BIT_WAIT_FOR_ES; + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_MST_CTRL, val); + if (ret) + return ret; + + /* configure i2c master delay */ + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV4_CTRL, 0); + if (ret) + return ret; + + val = INV_MPU6050_BIT_I2C_SLV0_DLY_EN | + INV_MPU6050_BIT_I2C_SLV1_DLY_EN | + INV_MPU6050_BIT_I2C_SLV2_DLY_EN | + INV_MPU6050_BIT_I2C_SLV3_DLY_EN | + INV_MPU6050_BIT_DELAY_ES_SHADOW; + return regmap_write(st->map, INV_MPU6050_REG_I2C_MST_DELAY_CTRL, val); +} + +/** + * inv_mpu_aux_read() - read register function for i2c auxiliary bus + * @st: driver internal state. + * @addr: chip i2c Address + * @reg: chip register address + * @val: buffer for storing read bytes + * @size: number of bytes to read + * + * Returns 0 on success, a negative error code otherwise. + */ +int inv_mpu_aux_read(const struct inv_mpu6050_state *st, uint8_t addr, + uint8_t reg, uint8_t *val, size_t size) +{ + unsigned int status; + int ret; + + if (size > 0x0F) + return -EINVAL; + + /* setup i2c SLV0 control: i2c addr, register, enable + size */ + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0), + INV_MPU6050_BIT_I2C_SLV_RNW | addr); + if (ret) + return ret; + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg); + if (ret) + return ret; + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), + INV_MPU6050_BIT_SLV_EN | size); + if (ret) + return ret; + + /* do i2c xfer */ + ret = inv_mpu_i2c_master_xfer(st); + if (ret) + goto error_disable_i2c; + + /* disable i2c slave */ + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); + if (ret) + goto error_disable_i2c; + + /* check i2c status */ + ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status); + if (ret) + return ret; + if (status & INV_MPU6050_BIT_I2C_SLV0_NACK) + return -EIO; + + /* read data in registers */ + return regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA, + val, size); + +error_disable_i2c: + regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); + return ret; +} + +/** + * inv_mpu_aux_write() - write register function for i2c auxiliary bus + * @st: driver internal state. + * @addr: chip i2c Address + * @reg: chip register address + * @val: 1 byte value to write + * + * Returns 0 on success, a negative error code otherwise. + */ +int inv_mpu_aux_write(const struct inv_mpu6050_state *st, uint8_t addr, + uint8_t reg, uint8_t val) +{ + unsigned int status; + int ret; + + /* setup i2c SLV0 control: i2c addr, register, value, enable + size */ + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0), addr); + if (ret) + return ret; + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg); + if (ret) + return ret; + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(0), val); + if (ret) + return ret; + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), + INV_MPU6050_BIT_SLV_EN | 1); + if (ret) + return ret; + + /* do i2c xfer */ + ret = inv_mpu_i2c_master_xfer(st); + if (ret) + goto error_disable_i2c; + + /* disable i2c slave */ + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); + if (ret) + goto error_disable_i2c; + + /* check i2c status */ + ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status); + if (ret) + return ret; + if (status & INV_MPU6050_BIT_I2C_SLV0_NACK) + return -EIO; + + return 0; + +error_disable_i2c: + regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); + return ret; +} |