// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2010-2013 Bluecherry, LLC <https://www.bluecherrydvr.com>
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*
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* Original author:
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* Ben Collins <bcollins@ubuntu.com>
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*
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* Additional work by:
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* John Brooks <john.brooks@bluecherry.net>
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*/
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/* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
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* channel. The bus can only handle one i2c event at a time. The below handles
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* this all wrong. We should be using the status registers to see if the bus
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* is in use, and have a global lock to check the status register. Also,
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* the bulk of the work should be handled out-of-interrupt. The ugly loops
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* that occur during interrupt scare me. The ISR should merely signal
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* thread context, ACK the interrupt, and move on. -- BenC */
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#include <linux/kernel.h>
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#include <linux/sched/signal.h>
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#include "solo6x10.h"
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u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
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{
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struct i2c_msg msgs[2];
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u8 data;
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msgs[0].flags = 0;
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msgs[0].addr = addr;
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msgs[0].len = 1;
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msgs[0].buf = &off;
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msgs[1].flags = I2C_M_RD;
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msgs[1].addr = addr;
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msgs[1].len = 1;
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msgs[1].buf = &data;
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i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);
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return data;
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}
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void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
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u8 off, u8 data)
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{
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struct i2c_msg msgs;
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u8 buf[2];
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buf[0] = off;
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buf[1] = data;
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msgs.flags = 0;
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msgs.addr = addr;
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msgs.len = 2;
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msgs.buf = buf;
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i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
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}
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static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
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{
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u32 ctrl;
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ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);
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if (solo_dev->i2c_state == IIC_STATE_START)
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ctrl |= SOLO_IIC_START;
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if (wr) {
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ctrl |= SOLO_IIC_WRITE;
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} else {
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ctrl |= SOLO_IIC_READ;
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if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
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ctrl |= SOLO_IIC_ACK_EN;
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}
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if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
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ctrl |= SOLO_IIC_STOP;
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solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
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}
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static void solo_i2c_start(struct solo_dev *solo_dev)
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{
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u32 addr = solo_dev->i2c_msg->addr << 1;
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if (solo_dev->i2c_msg->flags & I2C_M_RD)
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addr |= 1;
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solo_dev->i2c_state = IIC_STATE_START;
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solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
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solo_i2c_flush(solo_dev, 1);
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}
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static void solo_i2c_stop(struct solo_dev *solo_dev)
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{
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solo_irq_off(solo_dev, SOLO_IRQ_IIC);
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solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
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solo_dev->i2c_state = IIC_STATE_STOP;
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wake_up(&solo_dev->i2c_wait);
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}
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static int solo_i2c_handle_read(struct solo_dev *solo_dev)
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{
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prepare_read:
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if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
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solo_i2c_flush(solo_dev, 0);
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return 0;
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}
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solo_dev->i2c_msg_ptr = 0;
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solo_dev->i2c_msg++;
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solo_dev->i2c_msg_num--;
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if (solo_dev->i2c_msg_num == 0) {
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solo_i2c_stop(solo_dev);
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return 0;
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}
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if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
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solo_i2c_start(solo_dev);
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} else {
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if (solo_dev->i2c_msg->flags & I2C_M_RD)
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goto prepare_read;
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else
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solo_i2c_stop(solo_dev);
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}
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return 0;
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}
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static int solo_i2c_handle_write(struct solo_dev *solo_dev)
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{
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retry_write:
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if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
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solo_reg_write(solo_dev, SOLO_IIC_TXD,
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solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
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solo_dev->i2c_msg_ptr++;
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solo_i2c_flush(solo_dev, 1);
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return 0;
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}
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solo_dev->i2c_msg_ptr = 0;
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solo_dev->i2c_msg++;
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solo_dev->i2c_msg_num--;
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if (solo_dev->i2c_msg_num == 0) {
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solo_i2c_stop(solo_dev);
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return 0;
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}
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if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
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solo_i2c_start(solo_dev);
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} else {
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if (solo_dev->i2c_msg->flags & I2C_M_RD)
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solo_i2c_stop(solo_dev);
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else
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goto retry_write;
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}
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return 0;
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}
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int solo_i2c_isr(struct solo_dev *solo_dev)
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{
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u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
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int ret = -EINVAL;
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if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS | SOLO_IIC_STATE_SIG_ERR)
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|| solo_dev->i2c_id < 0) {
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solo_i2c_stop(solo_dev);
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return -ENXIO;
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}
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switch (solo_dev->i2c_state) {
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case IIC_STATE_START:
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if (solo_dev->i2c_msg->flags & I2C_M_RD) {
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solo_dev->i2c_state = IIC_STATE_READ;
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ret = solo_i2c_handle_read(solo_dev);
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break;
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}
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solo_dev->i2c_state = IIC_STATE_WRITE;
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fallthrough;
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case IIC_STATE_WRITE:
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ret = solo_i2c_handle_write(solo_dev);
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break;
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case IIC_STATE_READ:
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solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
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solo_reg_read(solo_dev, SOLO_IIC_RXD);
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solo_dev->i2c_msg_ptr++;
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ret = solo_i2c_handle_read(solo_dev);
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break;
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default:
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solo_i2c_stop(solo_dev);
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}
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return ret;
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}
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static int solo_i2c_master_xfer(struct i2c_adapter *adap,
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struct i2c_msg msgs[], int num)
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{
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struct solo_dev *solo_dev = adap->algo_data;
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unsigned long timeout;
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int ret;
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int i;
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DEFINE_WAIT(wait);
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for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
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if (&solo_dev->i2c_adap[i] == adap)
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break;
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}
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if (i == SOLO_I2C_ADAPTERS)
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return num; /* XXX Right return value for failure? */
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mutex_lock(&solo_dev->i2c_mutex);
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solo_dev->i2c_id = i;
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solo_dev->i2c_msg = msgs;
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solo_dev->i2c_msg_num = num;
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solo_dev->i2c_msg_ptr = 0;
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solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
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solo_irq_on(solo_dev, SOLO_IRQ_IIC);
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solo_i2c_start(solo_dev);
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timeout = HZ / 2;
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for (;;) {
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prepare_to_wait(&solo_dev->i2c_wait, &wait,
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TASK_INTERRUPTIBLE);
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if (solo_dev->i2c_state == IIC_STATE_STOP)
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break;
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timeout = schedule_timeout(timeout);
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if (!timeout)
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break;
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if (signal_pending(current))
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break;
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}
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finish_wait(&solo_dev->i2c_wait, &wait);
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ret = num - solo_dev->i2c_msg_num;
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solo_dev->i2c_state = IIC_STATE_IDLE;
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solo_dev->i2c_id = -1;
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mutex_unlock(&solo_dev->i2c_mutex);
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return ret;
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}
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static u32 solo_i2c_functionality(struct i2c_adapter *adap)
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{
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return I2C_FUNC_I2C;
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}
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static const struct i2c_algorithm solo_i2c_algo = {
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.master_xfer = solo_i2c_master_xfer,
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.functionality = solo_i2c_functionality,
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};
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int solo_i2c_init(struct solo_dev *solo_dev)
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{
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int i;
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int ret;
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solo_reg_write(solo_dev, SOLO_IIC_CFG,
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SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);
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solo_dev->i2c_id = -1;
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solo_dev->i2c_state = IIC_STATE_IDLE;
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init_waitqueue_head(&solo_dev->i2c_wait);
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mutex_init(&solo_dev->i2c_mutex);
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for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
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struct i2c_adapter *adap = &solo_dev->i2c_adap[i];
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snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",
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SOLO6X10_NAME, i);
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adap->algo = &solo_i2c_algo;
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adap->algo_data = solo_dev;
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adap->retries = 1;
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adap->dev.parent = &solo_dev->pdev->dev;
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ret = i2c_add_adapter(adap);
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if (ret) {
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adap->algo_data = NULL;
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break;
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}
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}
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if (ret) {
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for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
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if (!solo_dev->i2c_adap[i].algo_data)
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break;
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i2c_del_adapter(&solo_dev->i2c_adap[i]);
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solo_dev->i2c_adap[i].algo_data = NULL;
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}
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return ret;
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}
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return 0;
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}
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void solo_i2c_exit(struct solo_dev *solo_dev)
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{
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int i;
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for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
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if (!solo_dev->i2c_adap[i].algo_data)
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continue;
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i2c_del_adapter(&solo_dev->i2c_adap[i]);
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solo_dev->i2c_adap[i].algo_data = NULL;
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}
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}
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