altos: Add power management to TRNG driver

Support suspend/resume of the TRNG power supply, delaying after resume
to wait for it to stabilize.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/drivers/ao_trng_send.c b/src/drivers/ao_trng_send.c
index 99994900aadbc3d1f8b7d2c174967fd21a2ef3f6..63366d3ef53baad6f4b9f0f2a107aeea0c76a79b 100644 (file)
--- a/src/drivers/ao_trng_send.c
+++ b/src/drivers/ao_trng_send.c
@@ -20,6 +20,9 @@
 #include <ao_crc.h>
 #include <ao_trng_send.h>
 #include <ao_exti.h>
+#include <ao_power.h>
+
+static uint8_t trng_running;
 
 static void
 ao_trng_send_raw(uint16_t *buf)
@@ -72,12 +75,15 @@ ao_trng_send(void)
 
        ao_crc_reset();
 
-       /* Delay long enough for the HV power supply to stabilize so that the
-        * first bits we read aren't of poor quality
-        */
-       ao_delay(AO_MS_TO_TICKS(250));
-
        for (;;) {
+               if (!trng_running) {
+                       /* Delay long enough for the HV power supply
+                        * to stabilize so that the first bits we read
+                        * aren't of poor quality
+                        */
+                       ao_delay(AO_MS_TO_TICKS(10));
+                       trng_running = TRUE;
+               }
                if (ao_send_raw()) {
                        ao_led_on(AO_LED_TRNG_RAW);
                        ao_trng_send_raw(buffer[usb_buf_id]);
@@ -95,9 +101,39 @@ ao_trng_send(void)
 
 static struct ao_task ao_trng_send_task;
 
+#if AO_POWER_MANAGEMENT
+
+static void ao_trng_suspend(void *arg)
+{
+       (void) arg;
+#ifdef AO_TRNG_ENABLE_PORT
+       ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 0);
+#endif
+       trng_running = FALSE;
+}
+
+static void ao_trng_resume(void *arg)
+{
+       (void) arg;
+#ifdef AO_TRNG_ENABLE_PORT
+       ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 1);
+#endif
+}
+
+static struct ao_power ao_trng_power = {
+       .suspend = ao_trng_suspend,
+       .resume = ao_trng_resume
+};
+
+#endif
+
 void
 ao_trng_send_init(void)
 {
+#ifdef AO_TRNG_ENABLE_PORT
+       ao_enable_output(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 1);
+       ao_power_register(&ao_trng_power);
+#endif
        ao_enable_input(AO_RAW_PORT, AO_RAW_BIT, AO_EXTI_MODE_PULL_UP);
        ao_add_task(&ao_trng_send_task, ao_trng_send, "trng_send");
 }