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// SAM4 I2C Port
//
// Copyright (C) 2018 Florian Heilmann <Florian.Heilmann@gmx.net>
// Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include "autoconf.h" // CONFIG_CLOCK_FREQ
#include "board/misc.h" // timer_from_us
#include "command.h" // shutdown
#include "gpio.h" // i2c_setup
#include "internal.h" // gpio_peripheral
#include "sam4e.h" // TWI0
#include "sched.h" // sched_shutdown
// I2C pin definitions
#define TWI0_SCL_BANK 'A'
#define TWI0_SCL_PIN PIO_PA4A_TWCK0
#define TWI0_SCL_PERIPH 'A'
#define TWI0_SDA_BANK 'A'
#define TWI0_SDA_PIN PIO_PA3A_TWD0
#define TWI0_SDA_PERIPH 'A'
#define TWI1_SCL_BANK 'B'
#define TWI1_SCL_PIN PIO_PB5A_TWCK1
#define TWI1_SCL_PERIPH 'A'
#define TWI1_SDA_BANK 'B'
#define TWI1_SDA_PIN PIO_PB4A_TWD1
#define TWI1_SDA_PERIPH 'A'
void
i2c_init(Twi *p_twi, uint32_t rate)
{
uint32_t twi_id = (p_twi == TWI0) ? ID_TWI0 : ID_TWI1;
if ((PMC->PMC_PCSR0 & (1u << twi_id)) == 0) {
PMC->PMC_PCER0 = 1 << twi_id;
}
if (p_twi == TWI0) {
gpio_set_peripheral(TWI0_SCL_BANK, TWI0_SCL_PIN, TWI0_SCL_PERIPH, 0);
gpio_set_peripheral(TWI0_SDA_BANK, TWI0_SDA_PIN, TWI0_SDA_PERIPH, 0);
} else {
gpio_set_peripheral(TWI1_SCL_BANK, TWI1_SCL_PIN, TWI1_SCL_PERIPH, 0);
gpio_set_peripheral(TWI1_SDA_BANK, TWI1_SDA_PIN, TWI1_SDA_PERIPH, 0);
}
p_twi->TWI_IDR = 0xFFFFFFFF;
(void)p_twi->TWI_SR;
p_twi->TWI_CR = TWI_CR_SWRST;
(void)p_twi->TWI_RHR;
p_twi->TWI_CR = TWI_CR_MSDIS;
p_twi->TWI_CR = TWI_CR_SVDIS;
p_twi->TWI_CR = TWI_CR_MSEN;
uint32_t cldiv = 0;
uint32_t chdiv = 0;
uint32_t ckdiv = 0;
cldiv = CONFIG_CLOCK_FREQ / ((rate > 384000 ? 384000 : rate) * 2) - 4;
while((cldiv > 255) && (ckdiv < 7)) {
ckdiv++;
cldiv /= 2;
}
if (rate > 348000) {
chdiv = CONFIG_CLOCK_FREQ / ((2 * rate - 384000) * 2) - 4;
while((chdiv > 255) && (ckdiv < 7)) {
ckdiv++;
chdiv /= 2;
}
} else {
chdiv = cldiv;
}
p_twi->TWI_CWGR = TWI_CWGR_CLDIV(cldiv) | \
TWI_CWGR_CHDIV(chdiv) | \
TWI_CWGR_CKDIV(ckdiv);
}
uint32_t
addr_to_u32(uint8_t addr_len, uint8_t *addr)
{
uint32_t address = addr[0];
if (addr_len > 1) {
address <<= 8;
address |= addr[1];
}
if (addr_len > 2) {
address <<= 8;
address |= addr[2];
}
if (addr_len > 3) {
shutdown("Addresses larger than 3 bytes are not supported");
}
return address;
}
struct i2c_config
i2c_setup(uint32_t bus, uint32_t rate, uint8_t addr)
{
if ((bus > 1) | (rate > 400000))
shutdown("Invalid i2c_setup parameters!");
Twi *p_twi = (bus == 0) ? TWI0 : TWI1;
i2c_init(p_twi, rate);
return (struct i2c_config){ .twi=p_twi, .addr=addr};
}
void
i2c_write(struct i2c_config config,
uint8_t write_len, uint8_t *write)
{
Twi *p_twi = config.twi;
uint32_t status;
uint32_t bytes_to_send = write_len;
p_twi->TWI_MMR = TWI_MMR_DADR(config.addr);
for(;;) {
status = p_twi->TWI_SR;
if (status & TWI_SR_NACK)
shutdown("I2C NACK error encountered!");
if (!(status & TWI_SR_TXRDY))
continue;
if (!bytes_to_send)
break;
p_twi->TWI_THR = *write++;
bytes_to_send--;
}
p_twi->TWI_CR = TWI_CR_STOP;
while(!(p_twi->TWI_SR& TWI_SR_TXCOMP)) {
}
}
static void
i2c_wait(Twi* p_twi, uint32_t bit, uint32_t timeout)
{
for (;;) {
uint32_t flags = p_twi->TWI_SR;
if (flags & bit)
break;
if (!timer_is_before(timer_read_time(), timeout))
shutdown("I2C timeout occured");
}
}
void
i2c_read(struct i2c_config config,
uint8_t reg_len, uint8_t *reg,
uint8_t read_len, uint8_t *read)
{
Twi *p_twi = config.twi;
uint32_t status;
uint32_t bytes_to_send=read_len;
uint8_t stop = 0;
p_twi->TWI_MMR = 0;
p_twi->TWI_MMR = TWI_MMR_MREAD | TWI_MMR_DADR(config.addr) |
((reg_len << TWI_MMR_IADRSZ_Pos) &
TWI_MMR_IADRSZ_Msk);
p_twi->TWI_IADR = 0;
p_twi->TWI_IADR = addr_to_u32(reg_len, reg);
if (bytes_to_send == 1) {
p_twi->TWI_CR = TWI_CR_START | TWI_CR_STOP;
stop = 1;
} else {
p_twi->TWI_CR = TWI_CR_START;
stop = 0;
}
while (bytes_to_send > 0) {
status = p_twi->TWI_SR;
if (status & TWI_SR_NACK) {
shutdown("I2C NACK error encountered!");
}
if (bytes_to_send == 1 && !stop) {
p_twi->TWI_CR = TWI_CR_STOP;
stop = 1;
}
i2c_wait(p_twi, TWI_SR_RXRDY, timer_read_time() + timer_from_us(5000));
if (!(status & TWI_SR_RXRDY)) {
continue;
}
*read++ = p_twi->TWI_RHR;
bytes_to_send--;
}
while (!(p_twi->TWI_SR & TWI_SR_TXCOMP)) {}
(void)p_twi->TWI_SR;
}
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