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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (C) 2010-2013 Bluecherry, LLC <https://www.bluecherrydvr.com>4 *5 * Original author:6 * Ben Collins <bcollins@ubuntu.com>7 *8 * Additional work by:9 * John Brooks <john.brooks@bluecherry.net>10 */11 12/* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c13 * channel. The bus can only handle one i2c event at a time. The below handles14 * this all wrong. We should be using the status registers to see if the bus15 * is in use, and have a global lock to check the status register. Also,16 * the bulk of the work should be handled out-of-interrupt. The ugly loops17 * that occur during interrupt scare me. The ISR should merely signal18 * thread context, ACK the interrupt, and move on. -- BenC */19 20#include <linux/kernel.h>21#include <linux/sched/signal.h>22 23#include "solo6x10.h"24 25u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)26{27 struct i2c_msg msgs[2];28 u8 data;29 30 msgs[0].flags = 0;31 msgs[0].addr = addr;32 msgs[0].len = 1;33 msgs[0].buf = &off;34 35 msgs[1].flags = I2C_M_RD;36 msgs[1].addr = addr;37 msgs[1].len = 1;38 msgs[1].buf = &data;39 40 i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);41 42 return data;43}44 45void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,46 u8 off, u8 data)47{48 struct i2c_msg msgs;49 u8 buf[2];50 51 buf[0] = off;52 buf[1] = data;53 msgs.flags = 0;54 msgs.addr = addr;55 msgs.len = 2;56 msgs.buf = buf;57 58 i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);59}60 61static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)62{63 u32 ctrl;64 65 ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);66 67 if (solo_dev->i2c_state == IIC_STATE_START)68 ctrl |= SOLO_IIC_START;69 70 if (wr) {71 ctrl |= SOLO_IIC_WRITE;72 } else {73 ctrl |= SOLO_IIC_READ;74 if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))75 ctrl |= SOLO_IIC_ACK_EN;76 }77 78 if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)79 ctrl |= SOLO_IIC_STOP;80 81 solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);82}83 84static void solo_i2c_start(struct solo_dev *solo_dev)85{86 u32 addr = solo_dev->i2c_msg->addr << 1;87 88 if (solo_dev->i2c_msg->flags & I2C_M_RD)89 addr |= 1;90 91 solo_dev->i2c_state = IIC_STATE_START;92 solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);93 solo_i2c_flush(solo_dev, 1);94}95 96static void solo_i2c_stop(struct solo_dev *solo_dev)97{98 solo_irq_off(solo_dev, SOLO_IRQ_IIC);99 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);100 solo_dev->i2c_state = IIC_STATE_STOP;101 wake_up(&solo_dev->i2c_wait);102}103 104static int solo_i2c_handle_read(struct solo_dev *solo_dev)105{106prepare_read:107 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {108 solo_i2c_flush(solo_dev, 0);109 return 0;110 }111 112 solo_dev->i2c_msg_ptr = 0;113 solo_dev->i2c_msg++;114 solo_dev->i2c_msg_num--;115 116 if (solo_dev->i2c_msg_num == 0) {117 solo_i2c_stop(solo_dev);118 return 0;119 }120 121 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {122 solo_i2c_start(solo_dev);123 } else {124 if (solo_dev->i2c_msg->flags & I2C_M_RD)125 goto prepare_read;126 else127 solo_i2c_stop(solo_dev);128 }129 130 return 0;131}132 133static int solo_i2c_handle_write(struct solo_dev *solo_dev)134{135retry_write:136 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {137 solo_reg_write(solo_dev, SOLO_IIC_TXD,138 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);139 solo_dev->i2c_msg_ptr++;140 solo_i2c_flush(solo_dev, 1);141 return 0;142 }143 144 solo_dev->i2c_msg_ptr = 0;145 solo_dev->i2c_msg++;146 solo_dev->i2c_msg_num--;147 148 if (solo_dev->i2c_msg_num == 0) {149 solo_i2c_stop(solo_dev);150 return 0;151 }152 153 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {154 solo_i2c_start(solo_dev);155 } else {156 if (solo_dev->i2c_msg->flags & I2C_M_RD)157 solo_i2c_stop(solo_dev);158 else159 goto retry_write;160 }161 162 return 0;163}164 165int solo_i2c_isr(struct solo_dev *solo_dev)166{167 u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);168 int ret = -EINVAL;169 170 171 if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS | SOLO_IIC_STATE_SIG_ERR)172 || solo_dev->i2c_id < 0) {173 solo_i2c_stop(solo_dev);174 return -ENXIO;175 }176 177 switch (solo_dev->i2c_state) {178 case IIC_STATE_START:179 if (solo_dev->i2c_msg->flags & I2C_M_RD) {180 solo_dev->i2c_state = IIC_STATE_READ;181 ret = solo_i2c_handle_read(solo_dev);182 break;183 }184 185 solo_dev->i2c_state = IIC_STATE_WRITE;186 fallthrough;187 case IIC_STATE_WRITE:188 ret = solo_i2c_handle_write(solo_dev);189 break;190 191 case IIC_STATE_READ:192 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =193 solo_reg_read(solo_dev, SOLO_IIC_RXD);194 solo_dev->i2c_msg_ptr++;195 196 ret = solo_i2c_handle_read(solo_dev);197 break;198 199 default:200 solo_i2c_stop(solo_dev);201 }202 203 return ret;204}205 206static int solo_i2c_master_xfer(struct i2c_adapter *adap,207 struct i2c_msg msgs[], int num)208{209 struct solo_dev *solo_dev = adap->algo_data;210 unsigned long timeout;211 int ret;212 int i;213 DEFINE_WAIT(wait);214 215 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {216 if (&solo_dev->i2c_adap[i] == adap)217 break;218 }219 220 if (i == SOLO_I2C_ADAPTERS)221 return num; /* XXX Right return value for failure? */222 223 mutex_lock(&solo_dev->i2c_mutex);224 solo_dev->i2c_id = i;225 solo_dev->i2c_msg = msgs;226 solo_dev->i2c_msg_num = num;227 solo_dev->i2c_msg_ptr = 0;228 229 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);230 solo_irq_on(solo_dev, SOLO_IRQ_IIC);231 solo_i2c_start(solo_dev);232 233 timeout = HZ / 2;234 235 for (;;) {236 prepare_to_wait(&solo_dev->i2c_wait, &wait,237 TASK_INTERRUPTIBLE);238 239 if (solo_dev->i2c_state == IIC_STATE_STOP)240 break;241 242 timeout = schedule_timeout(timeout);243 if (!timeout)244 break;245 246 if (signal_pending(current))247 break;248 }249 250 finish_wait(&solo_dev->i2c_wait, &wait);251 ret = num - solo_dev->i2c_msg_num;252 solo_dev->i2c_state = IIC_STATE_IDLE;253 solo_dev->i2c_id = -1;254 255 mutex_unlock(&solo_dev->i2c_mutex);256 257 return ret;258}259 260static u32 solo_i2c_functionality(struct i2c_adapter *adap)261{262 return I2C_FUNC_I2C;263}264 265static const struct i2c_algorithm solo_i2c_algo = {266 .master_xfer = solo_i2c_master_xfer,267 .functionality = solo_i2c_functionality,268};269 270int solo_i2c_init(struct solo_dev *solo_dev)271{272 int i;273 int ret;274 275 solo_reg_write(solo_dev, SOLO_IIC_CFG,276 SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);277 278 solo_dev->i2c_id = -1;279 solo_dev->i2c_state = IIC_STATE_IDLE;280 init_waitqueue_head(&solo_dev->i2c_wait);281 mutex_init(&solo_dev->i2c_mutex);282 283 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {284 struct i2c_adapter *adap = &solo_dev->i2c_adap[i];285 286 snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",287 SOLO6X10_NAME, i);288 adap->algo = &solo_i2c_algo;289 adap->algo_data = solo_dev;290 adap->retries = 1;291 adap->dev.parent = &solo_dev->pdev->dev;292 293 ret = i2c_add_adapter(adap);294 if (ret) {295 adap->algo_data = NULL;296 break;297 }298 }299 300 if (ret) {301 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {302 if (!solo_dev->i2c_adap[i].algo_data)303 break;304 i2c_del_adapter(&solo_dev->i2c_adap[i]);305 solo_dev->i2c_adap[i].algo_data = NULL;306 }307 return ret;308 }309 310 return 0;311}312 313void solo_i2c_exit(struct solo_dev *solo_dev)314{315 int i;316 317 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {318 if (!solo_dev->i2c_adap[i].algo_data)319 continue;320 i2c_del_adapter(&solo_dev->i2c_adap[i]);321 solo_dev->i2c_adap[i].algo_data = NULL;322 }323}324