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fix 8k read limit #22

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fix 8k read limit #22

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2 changes: 2 additions & 0 deletions include/i2c/i2c.h
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@ extern "C" {
#include <linux/i2c.h>
#include <linux/i2c-dev.h>

#define MAX_I2C_MSG_LEN 8192

/* I2c device */
typedef struct i2c_device {
int bus; /* I2C Bus fd, return from i2c_open */
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20 changes: 11 additions & 9 deletions src/i2c.c
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Expand Up @@ -214,9 +214,10 @@ ssize_t i2c_ioctl_write(const I2CDevice *device, unsigned int iaddr, const void
*/
ssize_t i2c_read(const I2CDevice *device, unsigned int iaddr, void *buf, size_t len)
{
ssize_t cnt;
ssize_t cnt, total_read = 0;
unsigned char addr[INT_ADDR_MAX_BYTES];
unsigned char delay = GET_I2C_DELAY(device->delay);
char *ptr = (char*)buf;

/* Set i2c slave address */
if (i2c_select(device->bus, device->addr, device->tenbit) == -1) {
Expand All @@ -237,15 +238,16 @@ ssize_t i2c_read(const I2CDevice *device, unsigned int iaddr, void *buf, size_t

/* Wait a while */
i2c_delay(delay);

/* Read count bytes data from int_addr specify address */
if ((cnt = read(device->bus, buf, len)) == -1) {

perror("Read i2c data error");
return -1;
while (total_read < len) {
size_t chunk_size = (len - total_read > MAX_I2C_MSG_LEN) ? MAX_I2C_MSG_LEN : (len - total_read);
if ((cnt = read(device->bus, ptr + total_read, chunk_size)) == -1) {
perror("Read i2c data error");
return -1;
}
total_read += cnt;
i2c_delay(delay);
}

return cnt;
return total_read;
}


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