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/* SPDX-License-Identifier: MIT */
/*
* Copied from Linux drivers/gpu/drm/ast/ast_mode.c
*/
#include <delay.h>
#include <device/i2c_simple.h>
#include "ast_drv.h"
static struct ast_private *ast;
#define _GET_INDEX_REG(x) ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, (x))
#define ASPEED_BUS 0
static int get_clock(unsigned int bus)
{
uint32_t val, val2, count, pass;
count = 0;
pass = 0;
val = (_GET_INDEX_REG(0x10) >> 4) & 0x01;
do {
val2 = (_GET_INDEX_REG(0x10) >> 4) & 0x01;
if (val == val2) {
pass++;
} else {
pass = 0;
val = (_GET_INDEX_REG(0x10) >> 4) & 0x01;
}
} while ((pass < 5) && (count++ < 0x10000));
return val & 1 ? 1 : 0;
}
static int get_data(unsigned int bus)
{
uint32_t val, val2, count, pass;
count = 0;
pass = 0;
val = (_GET_INDEX_REG(0x20) >> 5) & 0x01;
do {
val2 = (_GET_INDEX_REG(0x20) >> 5) & 0x01;
if (val == val2) {
pass++;
} else {
pass = 0;
val = (_GET_INDEX_REG(0x20) >> 5) & 0x01;
}
} while ((pass < 5) && (count++ < 0x10000));
return val & 1 ? 1 : 0;
}
static void set_clock(unsigned int bus, int clock)
{
int i;
u8 ujcrb7, jtemp;
for (i = 0; i < 0x10000; i++) {
ujcrb7 = ((clock & 0x01) ? 0 : 1);
ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf4, ujcrb7);
jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x01);
if (ujcrb7 == jtemp)
break;
}
}
static void set_data(unsigned int bus, int data)
{
int i;
u8 ujcrb7, jtemp;
for (i = 0; i < 0x10000; i++) {
ujcrb7 = ((data & 0x01) ? 0 : 1) << 2;
ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf1, ujcrb7);
jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x04);
if (ujcrb7 == jtemp)
break;
}
}
static struct software_i2c_ops ast_ops = {
.set_sda = set_data,
.set_scl = set_clock,
.get_sda = get_data,
.get_scl = get_clock,
};
int ast_software_i2c_read(struct ast_private *ast_priv, uint8_t edid[128])
{
struct software_i2c_ops *backup;
int ret;
backup = software_i2c[ASPEED_BUS];
software_i2c[ASPEED_BUS] = &ast_ops;
ast = ast_priv;
/* Ast POST pulled SDA and SCL low, recover the bus to a known state */
set_clock(ASPEED_BUS, 1);
set_data(ASPEED_BUS, 1);
udelay(100);
/* Need to reset internal EEPROM counter to 0 */
ret = i2c_read_bytes(ASPEED_BUS, 0x50, 0, edid, 128);
software_i2c[ASPEED_BUS] = backup;
return ret;
}
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