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