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// SPDX-License-Identifier: GPL-2.0-only
/*
* Coral-P(A)/Lime I2C adapter driver
*
* (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
*/
#include <linux/fb.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/export.h>
#include "mb862xxfb.h"
#include "mb862xx_reg.h"
static int mb862xx_i2c_wait_event(struct i2c_adapter *adap)
{
struct mb862xxfb_par *par = adap->algo_data;
u32 reg;
do {
udelay(10);
reg = inreg(i2c, GC_I2C_BCR);
if (reg & (I2C_INT | I2C_BER))
break;
} while (1);
return (reg & I2C_BER) ? 0 : 1;
}
static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr)
{
struct mb862xxfb_par *par = adap->algo_data;
outreg(i2c, GC_I2C_DAR, addr);
outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE);
outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START);
if (!mb862xx_i2c_wait_event(adap))
return -EIO;
par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
return par->i2c_rs;
}
static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte)
{
struct mb862xxfb_par *par = adap->algo_data;
outreg(i2c, GC_I2C_DAR, byte);
outreg(i2c, GC_I2C_BCR, I2C_START);
if (!mb862xx_i2c_wait_event(adap))
return -EIO;
return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
}
static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last)
{
struct mb862xxfb_par *par = adap->algo_data;
outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK));
if (!mb862xx_i2c_wait_event(adap))
return 0;
*byte = inreg(i2c, GC_I2C_DAR);
return 1;
}
static void mb862xx_i2c_stop(struct i2c_adapter *adap)
{
struct mb862xxfb_par *par = adap->algo_data;
outreg(i2c, GC_I2C_BCR, I2C_STOP);
outreg(i2c, GC_I2C_CCR, I2C_DISABLE);
par->i2c_rs = 0;
}
static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m)
{
int i, ret = 0;
int last = m->len - 1;
for (i = 0; i < m->len; i++) {
if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) {
ret = -EIO;
break;
}
}
return ret;
}
static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m)
{
int i, ret = 0;
for (i = 0; i < m->len; i++) {
if (!mb862xx_i2c_write_byte(adap, m->buf[i])) {
ret = -EIO;
break;
}
}
return ret;
}
static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
struct mb862xxfb_par *par = adap->algo_data;
struct i2c_msg *m;
int addr;
int i = 0, err = 0;
dev_dbg(par->dev, "%s: %d msgs\n", __func__, num);
for (i = 0; i < num; i++) {
m = &msgs[i];
if (!m->len) {
dev_dbg(par->dev, "%s: null msgs\n", __func__);
continue;
}
addr = m->addr;
if (m->flags & I2C_M_RD)
addr |= 1;
err = mb862xx_i2c_do_address(adap, addr);
if (err < 0)
break;
if (m->flags & I2C_M_RD)
err = mb862xx_i2c_read(adap, m);
else
err = mb862xx_i2c_write(adap, m);
}
if (i)
mb862xx_i2c_stop(adap);
return (err < 0) ? err : i;
}
static u32 mb862xx_func(struct i2c_adapter *adap)
{
return I2C_FUNC_SMBUS_BYTE_DATA;
}
static const struct i2c_algorithm mb862xx_algo = {
.master_xfer = mb862xx_xfer,
.functionality = mb862xx_func,
};
static struct i2c_adapter mb862xx_i2c_adapter = {
.name = "MB862xx I2C adapter",
.algo = &mb862xx_algo,
.owner = THIS_MODULE,
};
int mb862xx_i2c_init(struct mb862xxfb_par *par)
{
mb862xx_i2c_adapter.algo_data = par;
par->adap = &mb862xx_i2c_adapter;
return i2c_add_adapter(par->adap);
}
void mb862xx_i2c_exit(struct mb862xxfb_par *par)
{
if (par->adap) {
i2c_del_adapter(par->adap);
par->adap = NULL;
}
}
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