| /* 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; |
| } |