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Fix for PWM on Beaglebone black with a kernel > 3.8.13 #273

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Fix for PWM on Beaglebone black with a kernel > 3.8.13 #273

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23 changes: 23 additions & 0 deletions src/pwm/pwm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,9 @@ mraa_pwm_setup_duty_fp(mraa_pwm_context dev)
{
char bu[MAX_SIZE];
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwmchip%d/pwm%d/duty_cycle", dev->chipid, dev->pin);
if (!mraa_file_exist(bu)) {
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwm%d/duty_ns", dev->pin);
}

dev->duty_fp = open(bu, O_RDWR);
if (dev->duty_fp == -1) {
Expand All @@ -58,6 +61,9 @@ mraa_pwm_write_period(mraa_pwm_context dev, int period)
}
char bu[MAX_SIZE];
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwmchip%d/pwm%d/period", dev->chipid, dev->pin);
if (!mraa_file_exist(bu)) {
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwm%d/period_ns", dev->pin);
}

int period_f = open(bu, O_RDWR);
if (period_f == -1) {
Expand Down Expand Up @@ -97,6 +103,9 @@ mraa_pwm_read_period(mraa_pwm_context dev)
char bu[MAX_SIZE];
char output[MAX_SIZE];
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwmchip%d/pwm%d/period", dev->chipid, dev->pin);
if (!mraa_file_exist(bu)) {
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwm%d/period_ns", dev->pin);
}

int period_f = open(bu, O_RDWR);
if (period_f == -1) {
Expand Down Expand Up @@ -235,13 +244,21 @@ mraa_pwm_init_raw(int chipin, int pin)

char directory[MAX_SIZE];
snprintf(directory, MAX_SIZE, SYSFS_PWM "/pwmchip%d/pwm%d", dev->chipid, dev->pin);
if (!mraa_file_exist(directory)) {
snprintf(directory, MAX_SIZE, SYSFS_PWM "/pwm%d", dev->pin);
}

struct stat dir;
if (stat(directory, &dir) == 0 && S_ISDIR(dir.st_mode)) {
syslog(LOG_NOTICE, "pwm: Pin already exported, continuing");
dev->owner = 0; // Not Owner
} else {
char buffer[MAX_SIZE];
snprintf(buffer, MAX_SIZE, "/sys/class/pwm/pwmchip%d/export", dev->chipid);
if (!mraa_file_exist(buffer)) {
snprintf(buffer, MAX_SIZE, "/sys/class/pwm/export");
}

int export_f = open(buffer, O_WRONLY);
if (export_f == -1) {
syslog(LOG_ERR, "pwm: Failed to open export for writing");
Expand Down Expand Up @@ -341,6 +358,9 @@ mraa_pwm_enable(mraa_pwm_context dev, int enable)
}
char bu[MAX_SIZE];
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwmchip%d/pwm%d/enable", dev->chipid, dev->pin);
if (!mraa_file_exist(bu)) {
snprintf(bu, MAX_SIZE, "/sys/class/pwm/pwm%d/run", dev->pin);
}

int enable_f = open(bu, O_RDWR);

Expand All @@ -364,6 +384,9 @@ mraa_pwm_unexport_force(mraa_pwm_context dev)
{
char filepath[MAX_SIZE];
snprintf(filepath, MAX_SIZE, "/sys/class/pwm/pwmchip%d/unexport", dev->chipid);
if (!mraa_file_exist(filepath)) {
snprintf(filepath, MAX_SIZE, "/sys/class/pwm/unexport");
}

int unexport_f = open(filepath, O_WRONLY);
if (unexport_f == -1) {
Expand Down