First commit

2 files changed, 195 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..a157cee
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,18 @@
+TARGET = pwm
+OBJ = pwm.o
+
+#export STAGING_DIR = ~/openwrt/staging_dir
+#TOOLCHAIN_DIR = $(STAGING_DIR)/toolchain-mips_34kc_gcc-4.8-linaro_uClibc-0.9.33.2
+#LDCFLAGS = -L$(TOOLCHAIN_DIR)/usr/lib
+#LD_LIBRARY_PATH = $(TOOLCHAIN_DIR)/usr/lib
+
+CC = mipsel-openwrt-linux-gcc
+
+all: $(TARGET)
+
+$(TARGET): $(OBJ)
+	. ./env
+	$(CC) $(LCDFLAGS) -o $@ $^
+
+clean:
+	rm -f $(TARGET) *~ \#*\# *.o
diff --git a/pwm.c b/pwm.c
new file mode 100644
index 0000000..63e0fff
--- /dev/null
+++ b/pwm.c
@@ -0,0 +1,177 @@
+/*
+ * pwm.c: Simple program control hardware PWM on Omega2
+ *
+ *  Copyright (C) 2017, Alexey 'Cluster' Avdyukhin (clusterrr@clusterrr.com)
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <inttypes.h>
+
+#define printerr(fmt,...) do { fprintf(stderr, fmt, ## __VA_ARGS__); fflush(stderr); } while(0)
+
+#define PWM_ENABLE 0x10005000        // PWM Enable register
+#define PWM0_CON 0x10005010          // PWM0 Control register
+#define PWM0_HDURATION 0x10005014    // PWM0 High Duration register
+#define PWM0_LDURATION 0x10005018    // PWM0 Low Duration register
+#define PWM0_GDURATION 0x1000501C    // PWM0 Guard Duration register
+#define PWM0_SEND_DATA0 0x10005030   // PWM0 Send Data0 register
+#define PWM0_SEND_DATA1 0x10005034   // PWM0 Send Data1 register
+#define PWM0_WAVE_NUM 0x10005038     // PWM0 Wave Number register
+#define PWM0_DATA_WIDTH 0x1000503C   // PWM0 Data Width register
+#define PWM0_THRESH 0x10005040       // PWM0 Thresh register
+#define PWM0_SEND_WAVENUM 0x10005044 // PWM0 Send Wave Number register
+
+uint32_t devmem(uint32_t target, uint8_t size, uint8_t write, uint32_t value)
+{
+    int fd;
+    void *map_base, *virt_addr;
+    uint32_t pagesize = (unsigned)getpagesize(); /* or sysconf(_SC_PAGESIZE)  */
+    uint32_t map_size = pagesize;
+    uint32_t offset;
+    uint32_t result;
+
+    offset = (unsigned int)(target & (pagesize-1));
+    if (offset + size > pagesize ) {
+        // Access straddles page boundary:  add another page:
+        map_size += pagesize;
+    }
+
+    fd = open("/dev/mem", O_RDWR | O_SYNC);
+    if (fd == -1) {
+        printerr("Error opening /dev/mem (%d) : %s\n", errno, strerror(errno));
+        exit(1);
+    }
+
+    map_base = mmap(0, map_size, PROT_READ | PROT_WRITE, MAP_SHARED,
+                    fd, 
+                    target & ~((typeof(target))pagesize-1));
+    if (map_base == (void *) -1) {
+        printerr("Error mapping (%d) : %s\n", errno, strerror(errno));
+        exit(1);
+    }
+
+    virt_addr = map_base + offset;
+
+    if (write)
+    {
+        switch (size) {
+            case 1:
+                *((volatile uint8_t *) virt_addr) = value;
+                break;
+            case 2:
+                *((volatile uint16_t *) virt_addr) = value;
+                break;
+            case 4:
+                *((volatile uint32_t *) virt_addr) = value;
+                break;
+        }
+    }    
+
+    switch (size) {
+        case 1:
+            result = *((volatile uint8_t *) virt_addr);
+            break;
+        case 2:
+            result = *((volatile uint16_t *) virt_addr);
+            break;
+        case 4:
+            result = *((volatile uint32_t *) virt_addr);
+            break;
+    }
+
+    if (munmap(map_base, map_size) != 0) {
+        printerr("ERROR munmap (%d) %s\n", errno, strerror(errno));
+        exit(1);
+    }
+    close(fd);
+
+    return result;
+}
+
+static void usage(const char *cmd)
+{
+    fprintf(stderr, 
+        "\nUsage:\t%s pwm <channel> <frequency> <duty>\n",
+        "\nUsage:\t%s melody <channel> <frequency> <duration_ms> [<frequency> <duration_ms> [<frequency> <duration_ms> ...]]\n",
+        "\n",
+        cmd, cmd);
+}
+
+static void pwm(uint8_t channel, uint32_t freq, uint8_t duty)
+{
+    uint32_t enable = devmem(PWM_ENABLE, 4, 0, 0);
+
+    enable &= ~((uint32_t)(1<<channel));
+    devmem(PWM_ENABLE, 4, 1, enable);
+
+    // Need to disable PWM?
+    if (!freq)
+        return;
+
+    uint32_t reg_offset = 0x40 * channel;
+
+    uint32_t duration = 100000 / freq;
+    uint32_t duration0 = duration * duty / 100;
+    uint32_t duration1 = duration * (100-duty) / 100;
+
+    devmem(PWM0_CON + reg_offset, 4, 1, 0x7000);
+    devmem(PWM0_HDURATION + reg_offset, 4, 1, duration1-1);
+    devmem(PWM0_LDURATION + reg_offset, 4, 1, duration0-1);
+    devmem(PWM0_GDURATION + reg_offset, 4, 1, duration / 2 - 1);
+    devmem(PWM0_SEND_DATA0 + reg_offset, 4, 1, 0x55555555);
+    devmem(PWM0_SEND_DATA1 + reg_offset, 4, 1, 0x55555555);
+    devmem(PWM0_WAVE_NUM + reg_offset, 4, 1, 0);
+
+    enable |= 1<<channel;
+    devmem(PWM_ENABLE, 4, 1, enable);
+}
+
+int main(int argc, char **argv)
+{
+    const char *progname = argv[0];
+    if (argc < 3)
+    {
+        usage(progname);
+        exit(2);
+    }
+
+    uint8_t channel;
+    uint32_t freq;
+    uint8_t duty = 50;
+
+    if (sscanf(argv[1], "%d", &channel) != 1)
+    {
+        fprintf(stderr, "Invalid number\n");
+        exit(1);
+    }
+
+    if (sscanf(argv[2], "%d", &freq) != 1)
+    {
+        fprintf(stderr, "Invalid number\n");
+        exit(1);
+    }
+
+    if (argc >= 4)
+    {
+        if (sscanf(argv[3], "%d", &duty) != 1)
+        {
+            fprintf(stderr, "Invalid number\n");
+            exit(1);
+        }
+    }
+
+    pwm(channel, freq, duty);
+
+    return 0;
+}