inv_mpu_aux.c (5242B)
1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Copyright (C) 2019 TDK-InvenSense, Inc. 4 */ 5 6#include <linux/kernel.h> 7#include <linux/device.h> 8#include <linux/regmap.h> 9#include <linux/delay.h> 10 11#include "inv_mpu_aux.h" 12#include "inv_mpu_iio.h" 13 14/* 15 * i2c master auxiliary bus transfer function. 16 * Requires the i2c operations to be correctly setup before. 17 */ 18static int inv_mpu_i2c_master_xfer(const struct inv_mpu6050_state *st) 19{ 20 /* use 50hz frequency for xfer */ 21 const unsigned int freq = 50; 22 const unsigned int period_ms = 1000 / freq; 23 uint8_t d; 24 unsigned int user_ctrl; 25 int ret; 26 27 /* set sample rate */ 28 d = INV_MPU6050_FIFO_RATE_TO_DIVIDER(freq); 29 ret = regmap_write(st->map, st->reg->sample_rate_div, d); 30 if (ret) 31 return ret; 32 33 /* start i2c master */ 34 user_ctrl = st->chip_config.user_ctrl | INV_MPU6050_BIT_I2C_MST_EN; 35 ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl); 36 if (ret) 37 goto error_restore_rate; 38 39 /* wait for xfer: 1 period + half-period margin */ 40 msleep(period_ms + period_ms / 2); 41 42 /* stop i2c master */ 43 user_ctrl = st->chip_config.user_ctrl; 44 ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl); 45 if (ret) 46 goto error_stop_i2c; 47 48 /* restore sample rate */ 49 d = st->chip_config.divider; 50 ret = regmap_write(st->map, st->reg->sample_rate_div, d); 51 if (ret) 52 goto error_restore_rate; 53 54 return 0; 55 56error_stop_i2c: 57 regmap_write(st->map, st->reg->user_ctrl, st->chip_config.user_ctrl); 58error_restore_rate: 59 regmap_write(st->map, st->reg->sample_rate_div, st->chip_config.divider); 60 return ret; 61} 62 63/** 64 * inv_mpu_aux_init() - init i2c auxiliary bus 65 * @st: driver internal state 66 * 67 * Returns 0 on success, a negative error code otherwise. 68 */ 69int inv_mpu_aux_init(const struct inv_mpu6050_state *st) 70{ 71 unsigned int val; 72 int ret; 73 74 /* configure i2c master */ 75 val = INV_MPU6050_BITS_I2C_MST_CLK_400KHZ | 76 INV_MPU6050_BIT_WAIT_FOR_ES; 77 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_MST_CTRL, val); 78 if (ret) 79 return ret; 80 81 /* configure i2c master delay */ 82 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV4_CTRL, 0); 83 if (ret) 84 return ret; 85 86 val = INV_MPU6050_BIT_I2C_SLV0_DLY_EN | 87 INV_MPU6050_BIT_I2C_SLV1_DLY_EN | 88 INV_MPU6050_BIT_I2C_SLV2_DLY_EN | 89 INV_MPU6050_BIT_I2C_SLV3_DLY_EN | 90 INV_MPU6050_BIT_DELAY_ES_SHADOW; 91 return regmap_write(st->map, INV_MPU6050_REG_I2C_MST_DELAY_CTRL, val); 92} 93 94/** 95 * inv_mpu_aux_read() - read register function for i2c auxiliary bus 96 * @st: driver internal state. 97 * @addr: chip i2c Address 98 * @reg: chip register address 99 * @val: buffer for storing read bytes 100 * @size: number of bytes to read 101 * 102 * Returns 0 on success, a negative error code otherwise. 103 */ 104int inv_mpu_aux_read(const struct inv_mpu6050_state *st, uint8_t addr, 105 uint8_t reg, uint8_t *val, size_t size) 106{ 107 unsigned int status; 108 int ret; 109 110 if (size > 0x0F) 111 return -EINVAL; 112 113 /* setup i2c SLV0 control: i2c addr, register, enable + size */ 114 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0), 115 INV_MPU6050_BIT_I2C_SLV_RNW | addr); 116 if (ret) 117 return ret; 118 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg); 119 if (ret) 120 return ret; 121 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 122 INV_MPU6050_BIT_SLV_EN | size); 123 if (ret) 124 return ret; 125 126 /* do i2c xfer */ 127 ret = inv_mpu_i2c_master_xfer(st); 128 if (ret) 129 goto error_disable_i2c; 130 131 /* disable i2c slave */ 132 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); 133 if (ret) 134 goto error_disable_i2c; 135 136 /* check i2c status */ 137 ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status); 138 if (ret) 139 return ret; 140 if (status & INV_MPU6050_BIT_I2C_SLV0_NACK) 141 return -EIO; 142 143 /* read data in registers */ 144 return regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA, 145 val, size); 146 147error_disable_i2c: 148 regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); 149 return ret; 150} 151 152/** 153 * inv_mpu_aux_write() - write register function for i2c auxiliary bus 154 * @st: driver internal state. 155 * @addr: chip i2c Address 156 * @reg: chip register address 157 * @val: 1 byte value to write 158 * 159 * Returns 0 on success, a negative error code otherwise. 160 */ 161int inv_mpu_aux_write(const struct inv_mpu6050_state *st, uint8_t addr, 162 uint8_t reg, uint8_t val) 163{ 164 unsigned int status; 165 int ret; 166 167 /* setup i2c SLV0 control: i2c addr, register, value, enable + size */ 168 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0), addr); 169 if (ret) 170 return ret; 171 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg); 172 if (ret) 173 return ret; 174 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(0), val); 175 if (ret) 176 return ret; 177 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 178 INV_MPU6050_BIT_SLV_EN | 1); 179 if (ret) 180 return ret; 181 182 /* do i2c xfer */ 183 ret = inv_mpu_i2c_master_xfer(st); 184 if (ret) 185 goto error_disable_i2c; 186 187 /* disable i2c slave */ 188 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); 189 if (ret) 190 goto error_disable_i2c; 191 192 /* check i2c status */ 193 ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status); 194 if (ret) 195 return ret; 196 if (status & INV_MPU6050_BIT_I2C_SLV0_NACK) 197 return -EIO; 198 199 return 0; 200 201error_disable_i2c: 202 regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0); 203 return ret; 204}