Move exmaples to separate directory

examples/i2c.c

@@ -0,0 +1,89 @@
+#include <linux/i2c.h>
+#include <linux/i2c-dev.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+
+#define check(e) ({\
+		int ec = (e); \
+		if(ec < 0) {\
+		perror(#e); \
+		exit(1);\
+		}\
+		ec;\
+		})
+
+enum BME280Register {
+	ID = 0xd0,
+	CTRL_MEAS = 0xf4,
+	PRESS_MSB = 0xf5,
+};
+
+typedef struct {
+	int fd;
+} BME280;
+
+int i2c_read_register(int fd, uint8_t reg) {
+	if(write(fd, &reg, 1) < 0)
+		return -1;
+	uint8_t byte;
+	if(read(fd, &byte, 1) < 0)
+		return -1;
+	return byte;
+}
+
+int i2c_read_registers(int fd, uint8_t start_addr, uint8_t* values, size_t n_bytes) {
+	if(write(fd, &start_addr, 1) < 0)
+		return -1;
+	return read(fd, values, n_bytes);
+}
+
+int bme280_init(BME280* self, int fd) {
+	self->fd = fd;
+
+	if(i2c_read_register(fd, 0xd0) != 0x60)
+		return -ENOTSUP;
+	return 0;
+}
+
+int main() {
+	int bus = check(open("/dev/i2c-1", O_RDWR));
+	check(ioctl(bus, I2C_SLAVE, 0x76));
+
+#if 0
+	// Check I2C driver compatibility
+	unsigned long adapter_funcs;
+	check(ioctl(bus, I2C_FUNCS, &adapter_funcs));
+	for(size_t i = 0; i != (sizeof(funcs)/sizeof(*funcs)); ++i) {
+		if(adapter_funcs & funcs[i].bit)
+			puts(funcs[i].name);
+	}
+#endif
+
+	BME280 sensor;
+	check(bme280_init(&sensor, bus));
+
+	for(size_t j = 0; j != 10; ++j) {
+		uint8_t ctrl_meas = (0b001u << 5) | (0b001 << 2) | 0b11;
+		uint8_t bus_data[] = {CTRL_MEAS, ctrl_meas};
+		check(write(bus, bus_data, 2));
+
+		//TODO: should we sleep here? Maybe poll the busy flag?
+
+		uint8_t sensor_data[8];
+		check(i2c_read_registers(bus, PRESS_MSB, sensor_data, 8));
+
+		for(size_t i = 0; i != sizeof(sensor_data); ++i) {
+			printf("%02x ", sensor_data[i]);
+		}
+		puts("");
+
+		sleep(1);
+	}
+
+	close(bus);
+}