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stm32: add support for i2c read 

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>
This commit is contained in:
Arksine 2020-05-02 17:52:24 -04:00 committed by KevinOConnor
parent 2d4b520260
commit 72b3ab8b29
1 changed files with 39 additions and 3 deletions
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42
src/stm32/i2c.c
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@ -10,6 +10,7 @@
#include "gpio.h" // i2c_setup
#include "internal.h" // GPIO
#include "sched.h" // sched_shutdown
#include "board/irq.h" //irq_disable
struct i2c_info {
I2C_TypeDef *i2c;
@ -81,13 +82,20 @@ i2c_wait(I2C_TypeDef *i2c, uint32_t set, uint32_t clear, uint32_t timeout)
}
static void
i2c_start(I2C_TypeDef *i2c, uint8_t addr, uint32_t timeout)
i2c_start(I2C_TypeDef *i2c, uint8_t addr, uint8_t xfer_len,
uint32_t timeout)
{
i2c->CR1 = I2C_CR1_START | I2C_CR1_PE;
i2c_wait(i2c, I2C_SR1_SB, 0, timeout);
i2c->DR = addr;
if (addr & 0x01)
i2c->CR1 |= I2C_CR1_ACK;
i2c_wait(i2c, I2C_SR1_ADDR, 0, timeout);
irqstatus_t flag = irq_save();
uint32_t sr2 = i2c->SR2;
if (addr & 0x01 && xfer_len == 1)
i2c->CR1 = I2C_CR1_STOP | I2C_CR1_PE;
irq_restore(flag);
if (!(sr2 & I2C_SR2_MSL))
shutdown("Failed to send i2c addr");
}
@ -99,6 +107,18 @@ i2c_send_byte(I2C_TypeDef *i2c, uint8_t b, uint32_t timeout)
i2c_wait(i2c, I2C_SR1_TXE, 0, timeout);
}
static uint8_t
i2c_read_byte(I2C_TypeDef *i2c, uint32_t timeout, uint8_t remaining)
{
i2c_wait(i2c, I2C_SR1_RXNE, 0, timeout);
irqstatus_t flag = irq_save();
uint8_t b = i2c->DR;
if (remaining == 1)
i2c->CR1 = I2C_CR1_STOP | I2C_CR1_PE;
irq_restore(flag);
return b;
}
static void
i2c_stop(I2C_TypeDef *i2c, uint32_t timeout)
{
@ -112,7 +132,7 @@ i2c_write(struct i2c_config config, uint8_t write_len, uint8_t *write)
I2C_TypeDef *i2c = config.i2c;
uint32_t timeout = timer_read_time() + timer_from_us(5000);
i2c_start(i2c, config.addr, timeout);
i2c_start(i2c, config.addr, write_len, timeout);
while (write_len--)
i2c_send_byte(i2c, *write++, timeout);
i2c_stop(i2c, timeout);
@ -122,5 +142,21 @@ void
i2c_read(struct i2c_config config, uint8_t reg_len, uint8_t *reg
, uint8_t read_len, uint8_t *read)
{
shutdown("i2c_read not supported on stm32");
I2C_TypeDef *i2c = config.i2c;
uint32_t timeout = timer_read_time() + timer_from_us(5000);
uint8_t addr = config.addr | 0x01;
if (reg_len) {
// write the register
i2c_start(i2c, config.addr, reg_len, timeout);
while(reg_len--)
i2c_send_byte(i2c, *reg++, timeout);
}
// start/re-start and read data
i2c_start(i2c, addr, read_len, timeout);
while(read_len--) {
*read = i2c_read_byte(i2c, timeout, read_len);
read++;
}
i2c_wait(i2c, 0, I2C_SR1_RXNE, timeout);
}