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fw: Change to bit-banging I2C implementation for charger comm

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New code, compiles, but it's not tested yet!
This commit is contained in:
Ondrej Jirman 2021-09-01 00:47:44 +02:00
parent 4a1abce0eb
commit 574d68aa89
2 changed files with 189 additions and 148 deletions
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329
firmware/main.c
View File

@ -36,9 +36,6 @@
#ifndef CONFIG_STOCK_FW
#define CONFIG_STOCK_FW 1
#endif
#ifndef CONFIG_I2C_A
#define CONFIG_I2C_A 0
#endif
#define USB_DEBUG 0
@ -496,32 +493,18 @@ static uint8_t keyscan_scan(uint8_t* res)
static void ext_int_assert(void)
{
#if CONFIG_I2C_A
// modded prototype 3 POGO INT pin
P84 = 0;
PAGESW = 0;
P0_P8M0 &= ~BIT(4); // output
#else
// original prototype POGO INT pin
// POGO INT pin
P90 = 0;
PAGESW = 1;
P1_P9M0 &= ~BIT(0);
#endif
}
static void ext_int_deassert(void)
{
#if CONFIG_I2C_A
// modded prototype 3 POGO INT pin
P84 = 0;
PAGESW = 0;
P0_P8M0 |= BIT(4); // input
#else
// original prototype POGO INT pin
// POGO INT pin
P90 = 0;
PAGESW = 1;
P1_P9M0 |= BIT(0);
#endif
}
// }}}
@ -602,9 +585,6 @@ 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_I2C_A
REG_FW_FEATURES_I2CA |
#endif
0,
[REG_KEYMATRIX_SIZE] = 0xc6, // 12 x 6
@ -983,151 +963,215 @@ static void self_test_run(void)
#endif
// }}}
// {{{ I2C A forwarding
#if CONFIG_I2C_A
// {{{ Charger I2C bitbanging
#define CHARGER_ADDR 0x75u
// returns 1 on success
static __bit poll_flag(uint8_t flag)
// Inspired by: https://calcium3000.wordpress.com/2016/08/19/i2c-bit-banging-tutorial-part-i/
// TODO: recognize clock-stretching
#define CHG_SCL BIT(5)
#define CHG_SDA BIT(6)
#define CHG_INT BIT(7)
#define CHG_PORT P8
#define CHG_RELEASE_SCL P0_P8M0 &= ~CHG_SCL
#define CHG_PULL_SCL P0_P8M0 |= CHG_SCL
#define CHG_RELEASE_SDA P0_P8M0 &= ~CHG_SDA
#define CHG_PULL_SDA P0_P8M0 |= CHG_SDA
void i2c_init(void)
{
// set timeout for the duration of single transfer at 100kHz + some
// slack for slave clock stretching
PAGESW = 0;
P0_P8M0 |= CHG_SCL | CHG_SDA | CHG_INT; // set SCL/SDA to input (release I2C bus)
P8 &= ~(CHG_SCL | CHG_SDA); // set SCL/SDA to output low when changed to output mode
}
// returns 1 on busy/timeout, abort needed because the bus is locked
static __bit poll_scl_busy(void)
{
// timeout for clock stretching by the slave
T0_SET_TIMEOUT(2 * 250); // 250us
while (!TF0) {
if (P0_I2CASF & flag) {
P0_I2CASF &= ~flag;
return 1;
}
while (!TF0)
if (CHG_PORT & CHG_SCL)
return 0;
return 1;
}
void i2c_start_condition(void)
{
CHG_RELEASE_SCL;
CHG_RELEASE_SDA;
delay_us(5);
CHG_PULL_SDA;
delay_us(5);
CHG_PULL_SCL;
delay_us(5);
}
void i2c_stop_condition(void)
{
CHG_PULL_SDA;
delay_us(5);
CHG_RELEASE_SCL;
delay_us(5);
CHG_RELEASE_SDA;
delay_us(5);
}
void i2c_write_bit(__bit b)
{
if (b)
CHG_RELEASE_SDA;
else
CHG_PULL_SDA;
delay_us(5);
CHG_RELEASE_SCL;
delay_us(5);
CHG_PULL_SCL;
}
__bit i2c_read_bit(void)
{
__bit b;
CHG_RELEASE_SDA;
delay_us(5);
CHG_RELEASE_SCL;
delay_us(5);
if (CHG_PORT & CHG_SDA)
b = 1;
else
b = 0;
CHG_PULL_SCL;
return b;
}
__bit i2c_write_byte(uint8_t data)
{
uint8_t i;
// write data
for (i = 0; i < 8; i++) {
i2c_write_bit(data & 0x80); // write the most-significant bit
data <<= 1;
}
return 0;
// read ack bit
return i2c_read_bit();
}
uint8_t i2c_read_byte(__bit ack)
{
uint8_t data = 0;
uint8_t i;
// read data
for (i = 0; i < 8; i++) {
data <<= 1;
data |= i2c_read_bit();
}
// send ack
i2c_write_bit(!ack);
return data;
}
__bit i2c_write_reg(uint8_t reg, uint8_t data)
{
__bit ok = 0;
PAGESW = 0;
i2c_start_condition();
if (!i2c_write_byte(CHARGER_ADDR << 1))
goto stop;
if (!i2c_write_byte(reg))
goto stop;
if (!i2c_write_byte(data))
goto stop;
ok = 1;
stop:
i2c_stop_condition();
return ok;
}
__bit i2c_read_reg(uint8_t reg, uint8_t* data)
{
__bit ok = 0;
PAGESW = 0;
i2c_start_condition();
if (!i2c_write_byte(CHARGER_ADDR << 1))
goto stop;
if (!i2c_write_byte(reg))
goto stop;
// repeated start
i2c_start_condition();
if (!i2c_write_byte((CHARGER_ADDR << 1) | 0x01))
goto stop;
*data = i2c_read_byte(0);
ok = 1;
stop:
i2c_stop_condition();
return ok;
}
static __bit charger_is_woke(void)
{
PAGESW = 1;
P1_PHCON2 |= BIT(3); // pull-up on P87-P84
PAGESW = 0;
P0_P8M0 |= BIT(7); // input
return !P87;
}
static __bit i2c_a_send_addr(uint8_t addr)
static uint8_t charger_read(void)
{
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 (!charger_is_woke())
return 0xff;
if (!i2c_a_send_addr(CHARGER_ADDR))
goto err;
if (!i2c_read_reg(REG_SYS(CHG_ADDR), &REG_SYS(CHG_DATA)))
return 0xff;
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;
return 0;;
err:
i2c_a_stop();
return status;
return 0;
}
static uint8_t i2c_a_write(void)
static uint8_t charger_write(void)
{
uint8_t status = 0xff;
// reset FSM
P0_I2CACR2 &= ~BIT(5);
P0_I2CACR2 |= BIT(5);
if (!charger_is_woke())
return 0xff;
if (!i2c_a_send_addr(CHARGER_ADDR))
goto err;
if (!i2c_write_reg(REG_SYS(CHG_ADDR), REG_SYS(CHG_DATA)))
return 0xff;
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;
return 0;
}
static void i2c_a_init(void)
static void charger_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
i2c_init();
}
#endif
// }}}
// {{{ System commands
@ -1148,12 +1192,10 @@ static void exec_system_command(void)
#endif
} else if (REG_SYS(COMMAND) == REG_SYS_COMMAND_USB_IAP) {
jump_to_usb_bootloader = 1;
#if CONFIG_I2C_A
} 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();
#endif
} else if (REG_SYS(COMMAND) == REG_SYS_COMMAND_CHG_READ) {
REG_SYS(COMMAND) = charger_read();
} else if (REG_SYS(COMMAND) == REG_SYS_COMMAND_CHG_WRITE) {
REG_SYS(COMMAND) = charger_write();
} else {
REG_SYS(COMMAND) = 0xff;
goto out_done;
@ -1917,9 +1959,8 @@ void main(void)
puts("ppkb firmware " FW_REVISION_STR " (user)\n");
#endif
#if CONFIG_I2C_A
i2c_a_init();
#endif
charger_init();
i2c_slave_init();
T1_SET_TIMEOUT(40000);

8
firmware/registers.h
View File

@ -42,15 +42,15 @@
#define REG_SYS_CONFIG 0x20
#define REG_SYS_CONFIG_SCAN_BLOCK BIT(0)
#define REG_SYS_I2CA_ADDR 0x21
#define REG_SYS_I2CA_DATA 0x22
#define REG_SYS_CHG_DATA 0x22
#define REG_SYS_CHG_ADDR 0x21
#define REG_SYS_COMMAND 0x23
#define REG_SYS_COMMAND_MCU_RESET 'r'
#define REG_SYS_COMMAND_USB_IAP 'i'
#define REG_SYS_COMMAND_SELFTEST 't'
#define REG_SYS_COMMAND_I2CA_READ 0x91
#define REG_SYS_COMMAND_I2CA_WRITE 0xA1
#define REG_SYS_COMMAND_CHG_READ 0x91
#define REG_SYS_COMMAND_CHG_WRITE 0xA1
#define REG_SYS_USER_APP_BLOCK 0x24
#define REG_SYS_USER_APP_BLOCK_MAGIC 0x53