Move exmaples to separate directory

examples/gpio.c

@@ -0,0 +1,59 @@
+#include <fcntl.h>
+#include <inttypes.h>
+#include <linux/gpio.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#define check(e)                                                               \
+  ({                                                                           \
+    int ec = (e);                                                              \
+    if (ec < 0) {                                                              \
+      perror(#e);                                                              \
+      exit(1);                                                                 \
+    }                                                                          \
+    ec;                                                                        \
+  })
+
+void gpio_info(int gpio_fd) {
+  struct gpiochip_info chip_info;
+  check(ioctl(gpio_fd, GPIO_GET_CHIPINFO_IOCTL, &chip_info));
+
+  printf("Name: %s, Label: %s, %" PRIu32 " lines\n", chip_info.name,
+         chip_info.label, chip_info.lines);
+
+  for (__u32 i = 0; i != chip_info.lines; ++i) {
+    struct gpio_v2_line_info line_info = {
+        .offset = i,
+    };
+    check(ioctl(gpio_fd, GPIO_V2_GET_LINEINFO_IOCTL, &line_info));
+    printf("Line %" PRIu32 ": '%s'. Consumer: %s\n", i, line_info.name,
+           line_info.consumer[0] ? line_info.consumer : "<none>");
+  }
+}
+
+int main() {
+  int gpio0 = check(open("/dev/gpiochip0", O_RDWR));
+
+  gpio_info(gpio0);
+
+#if 0
+  struct gpio_v2_line_request line_request = {
+      .offsets = {18},
+      .num_lines = 1,
+      .consumer = "my-super-cool-gpio",
+  };
+  check(ioctl(gpio0, GPIO_V2_GET_LINE_IOCTL, &line_request));
+
+  struct gpio_v2_line_info line_info = {
+      .offset = 18,
+  };
+  check(ioctl(gpio0, GPIO_V2_GET_LINEINFO_IOCTL, &line_info));
+  printf("Line 18: '%s'. Consumer: '%s'\n", line_info.name, line_info.consumer);
+
+  close(line_request.fd);
+#endif
+  close(gpio0);
+}

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);
+}