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i2c: Send MSB of address first for EEPROMs

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Close #3161.
This commit is contained in:
Sebastian Huber
2017-10-02 13:06:59 +02:00
parent a3199d91f3
commit 8ca15e26ba
1 changed files with 21 additions and 12 deletions
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33
cpukit/dev/i2c/eeprom.c
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@@ -48,6 +48,23 @@ static uint16_t eeprom_i2c_addr(eeprom *dev, uint32_t off)
| ((off >> dev->i2c_address_shift) & dev->i2c_address_mask); | ((off >> dev->i2c_address_shift) & dev->i2c_address_mask);
} }
static void eeprom_set_addr(
const eeprom *dev,
uint32_t off,
uint8_t addr[EEPROM_MAX_ADDRESS_BYTES]
)
{
int shift = 24 - (4 - dev->address_bytes) * 8;
addr[0] = (uint8_t) (off >> shift);
shift -= 8;
addr[1] = (uint8_t) (off >> shift);
shift -= 8;
addr[2] = (uint8_t) (off >> shift);
shift -= 8;
addr[3] = (uint8_t) (off >> shift);
}
static ssize_t eeprom_read( static ssize_t eeprom_read(
i2c_dev *base, i2c_dev *base,
void *buf, void *buf,
@@ -80,12 +97,7 @@ static ssize_t eeprom_read(
*/ */
uint16_t cur = (uint16_t) (todo < 255 ? todo : 255); uint16_t cur = (uint16_t) (todo < 255 ? todo : 255);
uint8_t addr[EEPROM_MAX_ADDRESS_BYTES] = { uint8_t addr[EEPROM_MAX_ADDRESS_BYTES];
(uint8_t) off,
(uint8_t) (off >> 8),
(uint8_t) (off >> 16),
(uint8_t) (off >> 24)
};
i2c_msg msgs[2] = { i2c_msg msgs[2] = {
{ {
.addr = i2c_addr, .addr = i2c_addr,
@@ -101,6 +113,7 @@ static ssize_t eeprom_read(
}; };
int err; int err;
eeprom_set_addr(dev, off, addr);
err = i2c_bus_transfer(dev->base.bus, &msgs[0], RTEMS_ARRAY_SIZE(msgs)); err = i2c_bus_transfer(dev->base.bus, &msgs[0], RTEMS_ARRAY_SIZE(msgs));
if (err != 0) { if (err != 0) {
return err; return err;
@@ -141,12 +154,7 @@ static ssize_t eeprom_write(
uint16_t i2c_addr = eeprom_i2c_addr(dev, off); uint16_t i2c_addr = eeprom_i2c_addr(dev, off);
uint16_t rem = dev->page_size - (off & (dev->page_size - 1)); uint16_t rem = dev->page_size - (off & (dev->page_size - 1));
uint16_t cur = (uint16_t) (todo < rem ? todo : rem); uint16_t cur = (uint16_t) (todo < rem ? todo : rem);
uint8_t addr[EEPROM_MAX_ADDRESS_BYTES] = { uint8_t addr[EEPROM_MAX_ADDRESS_BYTES];
(uint8_t) off,
(uint8_t) (off >> 8),
(uint8_t) (off >> 16),
(uint8_t) (off >> 24)
};
i2c_msg msgs[2] = { i2c_msg msgs[2] = {
{ {
.addr = i2c_addr, .addr = i2c_addr,
@@ -165,6 +173,7 @@ static ssize_t eeprom_write(
ssize_t m; ssize_t m;
rtems_interval timeout; rtems_interval timeout;
eeprom_set_addr(dev, off, addr);
err = i2c_bus_transfer(dev->base.bus, &msgs[0], RTEMS_ARRAY_SIZE(msgs)); err = i2c_bus_transfer(dev->base.bus, &msgs[0], RTEMS_ARRAY_SIZE(msgs));
if (err != 0) { if (err != 0) {
return err; return err;