pwrctl: Add latch output to power control
On the Zaius machine, the BMC signals that power up the CPU are gated by
a latch to protect against GPIO blips during BMC reset/power loss.
This adds an optional power GPIO configuration that controls the latch's
enable pin. Its behavior is to assert high when the op-pwrctl runs,
allowing power_up lines to propagate past their latches.
Signed-off-by: Xo Wang <xow@google.com>
Change-Id: Ibf0d1db771033cb9bba82575cca1bd21cfb3ad3d
diff --git a/op-pwrctl/power_control_obj.c b/op-pwrctl/power_control_obj.c
index cd13c68..679493c 100644
--- a/op-pwrctl/power_control_obj.c
+++ b/op-pwrctl/power_control_obj.c
@@ -208,6 +208,12 @@
uint8_t pgood_state;
// get gpio device paths
+ if(power_gpio->latch_out.name != NULL) { /* latch is optional */
+ rc = gpio_init(connection, &power_gpio->latch_out);
+ if(rc != GPIO_OK) {
+ error = rc;
+ }
+ }
rc = gpio_init(connection, &power_gpio->power_good_in);
if(rc != GPIO_OK) {
error = rc;
@@ -225,6 +231,26 @@
}
}
+ /* If there's a latch, it only needs to be set once. */
+ if(power_gpio->latch_out.name != NULL) {
+ do {
+ rc = gpio_open(&power_gpio->latch_out);
+ if(rc != GPIO_OK) {
+ /* Failures are non-fatal. */
+ break;
+ }
+ rc = gpio_write(&power_gpio->latch_out, 1);
+ gpio_close(&power_gpio->latch_out);
+ } while(0);
+ if (rc != GPIO_OK) {
+ error = rc;
+ g_print("PowerControl ERROR failed to assert latch %s rc=%d\n",
+ power_gpio->latch_out.name, rc);
+ } else {
+ g_print("PowerControl asserted latch %s\n", power_gpio->latch_out.name);
+ }
+ }
+
rc = gpio_open(&power_gpio->power_good_in);
if(rc != GPIO_OK) {
return rc;