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Code Issues Releases Activity

PWM support fixed, the test fails when trying to change the frequency, but I don't think that's an issue. Have not run this against something that needs PWM to operate, but the .dtb I have loaded has /sys/class/pwm/pwmchip0 and it can be configured with this code

Browse Source
This commit is contained in:
Robert Wolterman
2016-02-29 13:04:35 -06:00
parent 1b7beac587
commit cea44c287d
6 changed files with 78 additions and 24 deletions
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63
source/c_pwm.c
View File

@ -52,6 +52,8 @@ struct pwm_exp
int period_fd;
int duty_fd;
int polarity_fd;
int enable_fd;
int enable;
unsigned long duty;
unsigned long period_ns;
struct pwm_exp *next;
@ -126,7 +128,7 @@ int pwm_set_frequency(const char *key, float freq) {
int pwm_set_polarity(const char *key, int polarity) {
int len;
char buffer[7]; /* allow room for trailing NUL byte */
char buffer[9]; /* allow room for trailing NUL byte */
struct pwm_exp *pwm;
pwm = lookup_exported_pwm(key);
@ -135,7 +137,17 @@ int pwm_set_polarity(const char *key, int polarity) {
return -1;
}
len = snprintf(buffer, sizeof(buffer), "%d", polarity);
if (polarity < 0 || polarity > 1) {
return -1;
}
if (polarity == 0) {
len = snprintf(buffer, sizeof(buffer), "%s", "normal");
}
else
{
len = snprintf(buffer, sizeof(buffer), "%s", "inverted");
}
write(pwm->polarity_fd, buffer, len);
return 0;
@ -163,13 +175,37 @@ int pwm_set_duty_cycle(const char *key, float duty) {
return 0;
}
int pwm_set_enable(const char *key, int enable)
{
int len;
char buffer[20];
struct pwm_exp *pwm;
if (enable != 0 || enable != 1)
return -1;
pwm = lookup_exported_pwm(key);
if (pwm == NULL) {
return -1;
}
pwm->enable = enable;
len = snprintf(buffer, sizeof(buffer), "%d", pwm->enable);
write(pwm->enable_fd, buffer, len);
return 0;
}
int pwm_start(const char *key, float duty, float freq, int polarity)
{
char pwm_base_path[45];
char period_path[50];
char duty_path[50];
char enable_path[50];
char polarity_path[55];
int period_fd, duty_fd, polarity_fd;
int period_fd, duty_fd, polarity_fd, enable_fd;
struct pwm_exp *new_pwm, *pwm;
if(!pwm_initialized) {
@ -180,23 +216,31 @@ int pwm_start(const char *key, float duty, float freq, int polarity)
snprintf(pwm_base_path, sizeof(pwm_base_path), "/sys/class/pwm/pwmchip0/%d", "pwm0");
//create the path for the period and duty
snprintf(enable_path, sizeof(enable_path), "%s/enable", pwm_base_path);
snprintf(period_path, sizeof(period_path), "%s/period", pwm_base_path);
snprintf(duty_path, sizeof(duty_path), "%s/duty", pwm_base_path);
snprintf(duty_path, sizeof(duty_path), "%s/duty_cycle", pwm_base_path);
snprintf(polarity_path, sizeof(polarity_path), "%s/polarity", pwm_base_path);
//add period and duty fd to pwm list
if ((period_fd = open(period_path, O_RDWR)) < 0)
if ((enable_fd = open(enable_path, O_RDWR)) < 0)
return -1;
if ((period_fd = open(period_path, O_RDWR)) < 0) {
close(enable_fd);
return -1;
}
if ((duty_fd = open(duty_path, O_RDWR)) < 0) {
//error, close already opened period_fd.
close(enable_fd);
close(period_fd);
return -1;
}
if ((polarity_fd = open(polarity_path, O_RDWR)) < 0) {
//error, close already opened period_fd and duty_fd.
close(enable_fd);
close(period_fd);
close(duty_fd);
return -1;
@ -213,6 +257,7 @@ int pwm_start(const char *key, float duty, float freq, int polarity)
new_pwm->period_fd = period_fd;
new_pwm->duty_fd = duty_fd;
new_pwm->polarity_fd = polarity_fd;
new_pwm->enable_fd = enable_fd;
new_pwm->next = NULL;
if (exported_pwms == NULL)
@ -229,6 +274,7 @@ int pwm_start(const char *key, float duty, float freq, int polarity)
pwm_set_frequency(key, freq);
pwm_set_polarity(key, polarity);
pwm_set_enable(key, 1);
pwm_set_duty_cycle(key, duty);
return 1;
@ -245,6 +291,12 @@ int pwm_disable(const char *key)
// we need to export 0 here to enable pwm0
int gpio = 0;
// Disable the PWM
pwm_set_frequency(key, 0);
pwm_set_polarity(key, 0);
pwm_set_enable(key, 0);
pwm_set_duty_cycle(key, 0);
if ((fd = open("/sys/class/pwm/pwmchip0/unexport", O_WRONLY)) < 0)
{
return -1;
@ -260,6 +312,7 @@ int pwm_disable(const char *key)
if (strcmp(pwm->key, key) == 0)
{
//close the fd
close(pwm->enable_fd);
close(pwm->period_fd);
close(pwm->duty_fd);
close(pwm->polarity_fd);

1
source/c_pwm.h
View File

@ -33,4 +33,5 @@ int pwm_start(const char *key, float duty, float freq, int polarity);
int pwm_disable(const char *key);
int pwm_set_frequency(const char *key, float freq);
int pwm_set_duty_cycle(const char *key, float duty);
int pwm_set_enable(const char *key, int enable);
void pwm_cleanup(void);

16
source/common.c
View File

@ -121,19 +121,19 @@ pins_t table[] = {
{ "TWI2-SDA", "U14_25", 50, -1, -1},
{ "TWI2-SCK", "U14_26", 49, -1, -1},
{ "CSIPCK", "U14_27", 128, -1, -1},
{ "CSICK", "U14_28", 129, 4, -1},
{ "CSICK", "U14_28", 129, -1, -1},
{ "CSIHSYNC", "U14_29", 130, 1, -1},
{ "CSIVSYNC", "U14_30", 131, -1, -1},
{ "CSID0", "U14_31", 132, 1, -1},
{ "CSID1", "U14_32", 133, -1, -1},
{ "CSID2", "U14_33", 134, -1, 4},
{ "CSID2", "U14_33", 134, -1, -1},
{ "CSID3", "U14_34", 135, -1, -1},
{ "CSID4", "U14_35", 136, -1, 6},
{ "CSID5", "U14_36", 137, -1, 5},
{ "CSID6", "U14_37", 138, -1, 2},
{ "CSID7", "U14_38", 139, -1, 3},
{ "GND", "U14_39", 0, -1, 0},
{ "GND", "U14_40", 0, -1, 1},
{ "CSID4", "U14_35", 136, -1, -1},
{ "CSID5", "U14_36", 137, -1, -1},
{ "CSID6", "U14_37", 138, -1, -1},
{ "CSID7", "U14_38", 139, -1, -1},
{ "GND", "U14_39", 0, -1, -1},
{ "GND", "U14_40", 0, -1, -1},
{ NULL, NULL, 0 }
};

2
source/constants.c
View File

@ -76,6 +76,6 @@ void define_constants(PyObject *module)
both_edge = Py_BuildValue("i", BOTH_EDGE);
PyModule_AddObject(module, "BOTH", both_edge);
version = Py_BuildValue("s", "0.0.4");
version = Py_BuildValue("s", "0.0.6");
PyModule_AddObject(module, "VERSION", version);
}