Finalize sk6812 control via memory interface

src/fader.c

@@ -13,7 +13,7 @@ double nextFrame;
 
 int somethingChanged = 0; // indicates when a sk6812 update is required
 
-static const double interval = 0.01f;
+static const double interval = 1.0f / 75.0f;
 
 struct Colour {
 	float red, green, blue, white; // value range is 0.0 to 255.0

src/main.c

@@ -12,9 +12,9 @@
 
 #define PORT 2703
 
-#define NUM_MODULES 160
-#define GPIO_IDX    960
-#define BASE_ADDR   ((void*)0x40000000U)
+#define NUM_MODULES 300
+#define GPIO_IDX    961
+#define BASE_ADDR   ((void*)0x40010000U)
 
 int main(void)
 {

src/sk6812.c

@@ -5,6 +5,7 @@
 #include <sys/mman.h>
 #include <errno.h>
 
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -13,6 +14,8 @@
 
 int sk6812_init(struct sk6812_ctx *ctx, uint32_t gpio_idx, void *phys_baseptr, uint32_t num_modules)
 {
+	ctx->gpio_idx = gpio_idx;
+
 	/*
 	 * Setup memory map for LED memory.
 	 */
@@ -41,6 +44,34 @@ int sk6812_init(struct sk6812_ctx *ctx, uint32_t gpio_idx, void *phys_baseptr, u
 	// write number of modules to mapped memory
 	ctx->memptr->num_leds = num_modules;
 
+	/*
+	 * set up GPIO
+	 */
+	char filename[256];
+	char data[32];
+	int dlen;
+
+	int fd = open("/sys/class/gpio/export", O_WRONLY);
+	if(ctx->devmem_fd == -1) {
+		LOG(LVL_ERR, "sk6812: open(/sys/class/gpio/export, WRONLY) failed: %s.", strerror(errno));
+		return -1;
+	}
+
+	dlen = snprintf(data, 32, "%d\n", ctx->gpio_idx);
+	write(fd, data, dlen);
+	close(fd);
+
+	snprintf(filename, 256, "/sys/class/gpio/gpio%u/direction", ctx->gpio_idx);
+
+	fd = open(filename, O_WRONLY);
+	if(ctx->devmem_fd == -1) {
+		LOG(LVL_ERR, "sk6812: open(%s, WRONLY) failed: %s.", filename, strerror(errno));
+		return -1;
+	}
+
+	write(fd, "out\n", 4);
+	close(fd);
+
 	return 0;
 }
 
@@ -52,17 +83,42 @@ void sk6812_shutdown(struct sk6812_ctx *ctx)
 
 void sk6812_set_colour(struct sk6812_ctx *ctx, uint32_t module, uint8_t red, uint8_t green, uint8_t blue, uint8_t white)
 {
+	// despite the info in the datasheet, red and green are swapped :/
 	uint32_t value =
-		((uint32_t)red << 24U) |
-		((uint32_t)green << 16U) |
+		((uint32_t)green << 24U) |
+		((uint32_t)red << 16U) |
 		((uint32_t)blue << 8U) |
 		(uint32_t)white;
 
 	ctx->memptr->led_data[module] = value;
 }
 
-void sk6812_send_update(struct sk6812_ctx *ctx)
+int sk6812_send_update(struct sk6812_ctx *ctx)
 {
-	// TODO: generate rising edge on GPIO
+	LOG(LVL_DEBUG, "Updating with LED count: %u", ctx->memptr->num_leds);
+
+	char filename[256];
+
+	snprintf(filename, 256, "/sys/class/gpio/gpio%u/value", ctx->gpio_idx);
+
+	int fd = open(filename, O_WRONLY);
+	if(ctx->devmem_fd == -1) {
+		LOG(LVL_ERR, "sk6812: open(%s, WRONLY) failed: %s.", filename, strerror(errno));
+		return -1;
+	}
+
+	write(fd, "0\n", 2);
+	close(fd);
+
+	fd = open(filename, O_WRONLY);
+	if(ctx->devmem_fd == -1) {
+		LOG(LVL_ERR, "sk6812: open(%s, WRONLY) failed: %s.", filename, strerror(errno));
+		return -1;
+	}
+
+	write(fd, "1\n", 2);
+	close(fd);
+
+	return 0;
 }
 

src/sk6812.h

@@ -15,11 +15,12 @@ struct sk6812_ctx
 	char *gpio_value_path;
 	int devmem_fd;
 	size_t mapped_size;
+	uint32_t gpio_idx;
 };
 
 int sk6812_init(struct sk6812_ctx *ctx, uint32_t gpio_idx, void *phys_baseptr, uint32_t num_modules);
 void sk6812_shutdown(struct sk6812_ctx *ctx);
 void sk6812_set_colour(struct sk6812_ctx *ctx, uint32_t module, uint8_t red, uint8_t green, uint8_t blue, uint8_t white);
-void sk6812_send_update(struct sk6812_ctx *ctx);
+int sk6812_send_update(struct sk6812_ctx *ctx);
 
 #endif // SK6812_H

src/udpproto.c

@@ -17,6 +17,8 @@
 #define ADD_COLOUR   2
 #define SET_FADESTEP 3
 
+#define BYTES_PER_PACKET 7
+
 int sock;
 
 int udpproto_init(uint16_t port)
@@ -50,7 +52,8 @@ int udpproto_process(void)
 	uint8_t pkgbuf[65536];
 	ssize_t rcvbytes, offset = 0;
 
-	uint8_t r, g, b, w, action, module;
+	uint8_t r, g, b, w, action;
+	uint16_t module;
 	int fds_ready;
 
 	// check if there is data to be read (to prevent blocking)
@@ -81,14 +84,15 @@ int udpproto_process(void)
 
 	// parse commands from packet
 	offset = 0;
-	while(offset <= rcvbytes - 5) {
+	while(offset <= rcvbytes - BYTES_PER_PACKET) {
 		action = pkgbuf[offset + 0];
-		module = pkgbuf[offset + 1];
-		r      = pkgbuf[offset + 2];
-		g      = pkgbuf[offset + 3];
-		b      = pkgbuf[offset + 4];
-		w      = pkgbuf[offset + 5];
-		offset += 5;
+		module = (uint16_t)pkgbuf[offset + 1] << 8;
+		module |= pkgbuf[offset + 2];
+		r      = pkgbuf[offset + 3];
+		g      = pkgbuf[offset + 4];
+		b      = pkgbuf[offset + 5];
+		w      = pkgbuf[offset + 6];
+		offset += BYTES_PER_PACKET;
 
 		switch(action) {
 			case SET_COLOUR:
@@ -112,7 +116,7 @@ int udpproto_process(void)
 		}
 	}
 
-	return rcvbytes / 6; // number of commands in packet
+	return rcvbytes / BYTES_PER_PACKET; // number of commands in packet
 }
 
 void udpproto_shutdown(void)