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https://github.com/Atmosphere-NX/Atmosphere.git
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104 lines
3.1 KiB
C
104 lines
3.1 KiB
C
/*
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* Copyright (c) 2018-2019 Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "i2c.h"
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#include "timer.h"
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/* Prototypes for internal commands. */
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void i2c_load_config(void);
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int i2c_write(unsigned int device, uint32_t val, unsigned int num_bytes);
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int i2c_send_byte_command(unsigned int device, unsigned char reg, unsigned char b);
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/* Load hardware config for I2C4. */
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void i2c_load_config(void) {
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/* Set MSTR_CONFIG_LOAD, TIMEOUT_CONFIG_LOAD, undocumented bit. */
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I2C_I2C_CONFIG_LOAD_0 = 0x25;
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/* Wait a bit for master config to be loaded. */
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for (unsigned int i = 0; i < 20; i++) {
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timer_wait(1);
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if (!(I2C_I2C_CONFIG_LOAD_0 & 1)) {
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break;
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}
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}
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}
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/* Initialize I2C4. */
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void i2c_init(void) {
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/* Setup divisor, and clear the bus. */
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I2C_I2C_CLK_DIVISOR_REGISTER_0 = 0x50001;
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I2C_I2C_BUS_CLEAR_CONFIG_0 = 0x90003;
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/* Load hardware configuration. */
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i2c_load_config();
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/* Wait a while until BUS_CLEAR_DONE is set. */
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for (unsigned int i = 0; i < 10; i++) {
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timer_wait(20000);
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if (I2C_INTERRUPT_STATUS_REGISTER_0 & 0x800) {
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break;
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}
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}
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/* Read the BUS_CLEAR_STATUS. Result doesn't matter. */
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I2C_I2C_BUS_CLEAR_STATUS_0;
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/* Read and set the Interrupt Status. */
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uint32_t int_status = I2C_INTERRUPT_STATUS_REGISTER_0;
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I2C_INTERRUPT_STATUS_REGISTER_0 = int_status;
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}
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/* Writes a value to an i2c device. */
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int i2c_write(unsigned int device, uint32_t val, unsigned int num_bytes) {
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if (num_bytes > 4) {
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return 0;
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}
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/* Set device for 7-bit mode. */
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I2C_I2C_CMD_ADDR0_0 = device << 1;
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/* Load in data to write. */
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I2C_I2C_CMD_DATA1_0 = val;
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/* Set config with LENGTH = num_bytes, NEW_MASTER_FSM, DEBOUNCE_CNT = 4T. */
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I2C_I2C_CNFG_0 = ((num_bytes << 1) - 2) | 0x2800;
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i2c_load_config();
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/* Config |= SEND; */
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I2C_I2C_CNFG_0 |= 0x200;
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while (I2C_I2C_STATUS_0 & 0x100) {
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/* Wait until not busy. */
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}
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/* Return CMD1_STAT == SL1_XFER_SUCCESSFUL. */
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return (I2C_I2C_STATUS_0 & 0xF) == 0;
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}
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/* Writes a byte val to reg for given device. */
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int i2c_send_byte_command(unsigned int device, unsigned char reg, unsigned char b) {
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uint32_t val = (reg) | (b << 8);
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/* Write 1 byte (reg) + 1 byte (value) */
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return i2c_write(device, val, 2);
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}
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/* Actually reset device 27. This might turn off the screen? */
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int i2c_send_reset_cmd(void) {
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/* Write 00 to Device 27 Reg 00. */
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return i2c_send_byte_command(27, 0, 0);
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}
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