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1// SPDX-License-Identifier: GPL-2.02/*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 bus65 * @st: driver internal state66 *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 /*75 * Code based on the vendor Linux kernel v3.0,76 * the exact meaning is unknown.77 */78 if (st->chip_type == INV_MPU9150) {79 unsigned int mask = BIT(7);80 81 val = st->level_shifter ? mask : 0;82 ret = regmap_update_bits(st->map, 0x1, mask, val);83 if (ret)84 return ret;85 }86 87 /* configure i2c master */88 val = INV_MPU6050_BITS_I2C_MST_CLK_400KHZ |89 INV_MPU6050_BIT_WAIT_FOR_ES;90 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_MST_CTRL, val);91 if (ret)92 return ret;93 94 /* configure i2c master delay */95 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV4_CTRL, 0);96 if (ret)97 return ret;98 99 val = INV_MPU6050_BIT_I2C_SLV0_DLY_EN |100 INV_MPU6050_BIT_I2C_SLV1_DLY_EN |101 INV_MPU6050_BIT_I2C_SLV2_DLY_EN |102 INV_MPU6050_BIT_I2C_SLV3_DLY_EN |103 INV_MPU6050_BIT_DELAY_ES_SHADOW;104 return regmap_write(st->map, INV_MPU6050_REG_I2C_MST_DELAY_CTRL, val);105}106 107/**108 * inv_mpu_aux_read() - read register function for i2c auxiliary bus109 * @st: driver internal state.110 * @addr: chip i2c Address111 * @reg: chip register address112 * @val: buffer for storing read bytes113 * @size: number of bytes to read114 *115 * Returns 0 on success, a negative error code otherwise.116 */117int inv_mpu_aux_read(const struct inv_mpu6050_state *st, uint8_t addr,118 uint8_t reg, uint8_t *val, size_t size)119{120 unsigned int status;121 int ret;122 123 if (size > 0x0F)124 return -EINVAL;125 126 /* setup i2c SLV0 control: i2c addr, register, enable + size */127 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0),128 INV_MPU6050_BIT_I2C_SLV_RNW | addr);129 if (ret)130 return ret;131 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg);132 if (ret)133 return ret;134 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),135 INV_MPU6050_BIT_SLV_EN | size);136 if (ret)137 return ret;138 139 /* do i2c xfer */140 ret = inv_mpu_i2c_master_xfer(st);141 if (ret)142 goto error_disable_i2c;143 144 /* disable i2c slave */145 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);146 if (ret)147 goto error_disable_i2c;148 149 /* check i2c status */150 ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);151 if (ret)152 return ret;153 if (status & INV_MPU6050_BIT_I2C_SLV0_NACK)154 return -EIO;155 156 /* read data in registers */157 return regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA,158 val, size);159 160error_disable_i2c:161 regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);162 return ret;163}164 165/**166 * inv_mpu_aux_write() - write register function for i2c auxiliary bus167 * @st: driver internal state.168 * @addr: chip i2c Address169 * @reg: chip register address170 * @val: 1 byte value to write171 *172 * Returns 0 on success, a negative error code otherwise.173 */174int inv_mpu_aux_write(const struct inv_mpu6050_state *st, uint8_t addr,175 uint8_t reg, uint8_t val)176{177 unsigned int status;178 int ret;179 180 /* setup i2c SLV0 control: i2c addr, register, value, enable + size */181 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0), addr);182 if (ret)183 return ret;184 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg);185 if (ret)186 return ret;187 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(0), val);188 if (ret)189 return ret;190 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),191 INV_MPU6050_BIT_SLV_EN | 1);192 if (ret)193 return ret;194 195 /* do i2c xfer */196 ret = inv_mpu_i2c_master_xfer(st);197 if (ret)198 goto error_disable_i2c;199 200 /* disable i2c slave */201 ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);202 if (ret)203 goto error_disable_i2c;204 205 /* check i2c status */206 ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);207 if (ret)208 return ret;209 if (status & INV_MPU6050_BIT_I2C_SLV0_NACK)210 return -EIO;211 212 return 0;213 214error_disable_i2c:215 regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);216 return ret;217}218