firmware: Allow to read/write single registers from a charger

This code uses existing system command functionality. The I2C
registers are placed in front of system command register, to
allow for a single transaction proxied I2C A reads/writes.

Not tested, yet.
This commit is contained in:
Samuel Holland 2021-07-08 22:49:53 -05:00 committed by Ondrej Jirman
parent c3272eb4ef
commit 394af632aa
2 changed files with 154 additions and 5 deletions

View file

@ -36,6 +36,9 @@
#ifndef CONFIG_STOCK_FW
#define CONFIG_STOCK_FW 1
#endif
#ifndef CONFIG_I2C_A
#define CONFIG_I2C_A 1
#endif
#define USB_DEBUG 0
@ -573,6 +576,8 @@ static uint8_t crc8(const uint8_t *pdata, size_t nbytes)
#include "registers.h"
#define REG_SYS(n) ctl_regs[REG_SYS_##n - REG_SYS_CONFIG]
// all the variables are volatile because they can be accessed
// from interrupt context of I2C interrupt handler
@ -592,12 +597,15 @@ static volatile uint8_t __idata ro_regs[REG_KEYMATRIX_STATE_END + 1] = {
#endif
#if CONFIG_STOCK_FW
REG_FW_FEATURES_STOCK_FW |
#endif
#if CONFIG_I2CA
REG_FW_FEATURES_I2CA |
#endif
0,
[REG_KEYMATRIX_SIZE] = 0xc6, // 12 x 6
};
static volatile uint8_t ctl_regs[3] = {0, 0, 0};
static volatile uint8_t ctl_regs[5] = {0, 0, 0, 0, 0};
static volatile __bit sys_cmd_run = 0;
static volatile uint8_t reg_addr = 0;
@ -970,9 +978,137 @@ static void self_test_run(void)
#endif
// }}}
// {{{ System commands
// {{{ I2C A forwarding
#define REG_SYS(n) ctl_regs[REG_SYS_##n - REG_SYS_CONFIG]
#if CONFIG_I2C_A
#define CHARGER_ADDR 0x75u
// returns 1 on success
static __bit poll_flag(uint8_t flag)
{
// set timeout for the duration of single transfer at 100kHz + some
// slack for slave clock stretching
T0_SET_TIMEOUT(2 * 250); // 250us
while (!TF0) {
if (P0_I2CASF & flag) {
P0_I2CASF &= ~flag;
return 1;
}
}
return 0;
}
static __bit i2c_a_send_addr(uint8_t addr)
{
P0_I2CASA = addr;
P0_I2CACR1 |= BIT(7); // strobe
if (!poll_flag(BIT(0)))
return 0;
if (!(P0_I2CACR1 & BIT(2))) // ACK
return 0;
return 1;
}
static __bit i2c_a_send_data(uint8_t data)
{
P0_I2CADB = data;
P0_I2CACR1 |= BIT(7); // strobe
if (!poll_flag(BIT(0)))
return 0;
if (!(P0_I2CACR1 & BIT(2))) // ACK
return 0;
return 1;
}
static void i2c_a_stop(void)
{
P0_I2CACR1 |= BIT(4); // stop
poll_flag(BIT(2));
// and finaly do a reset just in case
P0_I2CACR2 &= ~BIT(5);
P0_I2CACR2 |= BIT(5);
}
static uint8_t i2c_a_read(void)
{
uint8_t status = 0xff;
// reset FSM
P0_I2CACR2 &= ~BIT(5);
P0_I2CACR2 |= BIT(5);
if (!i2c_a_send_addr(CHARGER_ADDR))
goto err;
if (!i2c_a_send_data(REG_SYS(I2CA_ADDR)))
goto err;
if (!i2c_a_send_addr(CHARGER_ADDR | BIT(0)))
goto err;
P0_I2CACR1 |= BIT(7) | BIT(4); // strobe + stop
if (!poll_flag(BIT(2))) // poll for stop bit
goto err;
// read received data
REG_SYS(I2CA_DATA) = P0_I2CBDB;
status = 0;
err:
i2c_a_stop();
return status;
}
static uint8_t i2c_a_write(void)
{
uint8_t status = 0xff;
// reset FSM
P0_I2CACR2 &= ~BIT(5);
P0_I2CACR2 |= BIT(5);
if (!i2c_a_send_addr(CHARGER_ADDR))
goto err;
if (!i2c_a_send_data(REG_SYS(I2CA_ADDR)))
goto err;
if (!i2c_a_send_data(REG_SYS(I2CA_DATA)))
goto err;
status = 0;
err:
i2c_a_stop();
return status;
}
static void i2c_a_init(void)
{
PAGESW = 0;
// un-powerdown I2CA
P0_DEVPD2 &= ~BIT(0);
P0_I2CACR1 = BIT(6); // master mode
P0_I2CACR2 = BIT(5) | 0x07 << 1 | BIT(0); // 100kHz mode, enable
}
#endif
// }}}
// {{{ System commands
static void exec_system_command(void)
{
@ -991,6 +1127,10 @@ static void exec_system_command(void)
#endif
} else if (REG_SYS(COMMAND) == REG_SYS_COMMAND_USB_IAP) {
jump_to_usb_bootloader = 1;
} else if (REG_SYS(COMMAND) == REG_SYS_COMMAND_I2CA_READ) {
REG_SYS(COMMAND) = i2c_a_read();
} else if (REG_SYS(COMMAND) == REG_SYS_COMMAND_I2CA_WRITE) {
REG_SYS(COMMAND) = i2c_a_write();
} else {
REG_SYS(COMMAND) = 0xff;
goto out_done;
@ -1778,6 +1918,9 @@ void main(void)
puts("ppkb firmware " FW_REVISION_STR " (user)\n");
#endif
#if CONFIG_I2C_A
i2c_a_init();
#endif
i2c_slave_init();
T1_SET_TIMEOUT(40000);

View file

@ -32,6 +32,7 @@
#define REG_FW_FEATURES_FLASHING_MODE BIT(1)
#define REG_FW_FEATURES_SELF_TEST BIT(2)
#define REG_FW_FEATURES_STOCK_FW BIT(3)
#define REG_FW_FEATURES_I2CA BIT(4)
#define REG_KEYMATRIX_SIZE 0x06
#define REG_KEYMATRIX_STATE_CRC8 0x07
@ -42,12 +43,17 @@
#define REG_SYS_CONFIG_SCAN_BLOCK BIT(0)
#define REG_SYS_CONFIG_USB_DEBUG_EN BIT(1)
#define REG_SYS_COMMAND 0x21
#define REG_SYS_I2CA_ADDR 0x21
#define REG_SYS_I2CA_DATA 0x22
#define REG_SYS_COMMAND 0x23
#define REG_SYS_COMMAND_MCU_RESET 'r'
#define REG_SYS_COMMAND_SELFTEST 't'
#define REG_SYS_COMMAND_USB_IAP 'i'
#define REG_SYS_COMMAND_I2CA_READ 'R'
#define REG_SYS_COMMAND_I2CA_WRITE 'W'
#define REG_SYS_USER_APP_BLOCK 0x22
#define REG_SYS_USER_APP_BLOCK 0x24
#define REG_SYS_USER_APP_BLOCK_MAGIC 0x53
#define REG_FLASH_DATA_START 0x70