diff options
Diffstat (limited to 'src/linux/i2c.c')
| -rw-r--r-- | src/linux/i2c.c | 41 |
1 files changed, 33 insertions, 8 deletions
diff --git a/src/linux/i2c.c b/src/linux/i2c.c index ce91656f..2994403f 100644 --- a/src/linux/i2c.c +++ b/src/linux/i2c.c @@ -4,7 +4,8 @@ // // This file may be distributed under the terms of the GNU GPLv3 license. #include <fcntl.h> // open -#include <linux/i2c-dev.h> // I2C_SLAVE +#include <linux/i2c-dev.h> // I2C_SLAVE i2c_msg +#include <linux/i2c.h> // i2c_rdwr_ioctl_data I2C_M_RD I2C_FUNC_I2C #include <stdio.h> // snprintf #include <sys/ioctl.h> // ioctl #include <unistd.h> // write @@ -42,6 +43,13 @@ i2c_open(uint32_t bus, uint8_t addr) report_errno("open i2c", fd); goto fail; } + // Test for I2C_RDWR support + unsigned long i2c_funcs; // datatype from ioctl spec. + ioctl(fd, I2C_FUNCS, &i2c_funcs); + if ((i2c_funcs & I2C_FUNC_I2C) == 0) { + report_errno("i2c does not support I2C_RDWR", fd); + goto fail; + } int ret = ioctl(fd, I2C_SLAVE, addr); if (ret < 0) { report_errno("ioctl i2c", fd); @@ -73,7 +81,7 @@ i2c_setup(uint32_t bus, uint32_t rate, uint8_t addr) // dtparam=i2c_baudrate=<rate> int fd = i2c_open(bus, addr); - return (struct i2c_config){.fd=fd}; + return (struct i2c_config){.fd=fd, .addr=addr}; } void @@ -91,12 +99,29 @@ void i2c_read(struct i2c_config config, uint8_t reg_len, uint8_t *reg , uint8_t read_len, uint8_t *data) { - if(reg_len != 0) - i2c_write(config, reg_len, reg); - int ret = read(config.fd, data, read_len); - if (ret != read_len) { - if (ret < 0) - report_errno("read value i2c", ret); + struct i2c_rdwr_ioctl_data i2c_data; + struct i2c_msg msgs[2]; + + if(reg_len != 0) { + msgs[0].addr = config.addr; + msgs[0].flags = 0x0; + msgs[0].len = reg_len; + msgs[0].buf = reg; + i2c_data.nmsgs = 2; + i2c_data.msgs = &msgs[0]; + } else { + i2c_data.nmsgs = 1; + i2c_data.msgs = &msgs[1]; + } + + msgs[1].addr = config.addr; + msgs[1].flags = I2C_M_RD; + msgs[1].len = read_len; + msgs[1].buf = data; + + int ret = ioctl(config.fd, I2C_RDWR, &i2c_data); + + if(ret < 0) { try_shutdown("Unable to read i2c device"); } } |