pwmcmds: Add Kconfig option to allow boards to disable hardware PWM commands

Some boards may not support hardware based PWM.  Update the build so
that those commands do not need to be compiled if they are not
available.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 78 insertions, 0 deletions

diff --git a/src/pwmcmds.c b/src/pwmcmds.c
new file mode 100644
index 00000000..bc9fec03
--- /dev/null
+++ b/src/pwmcmds.c
@@ -0,0 +1,78 @@
+// Commands for controlling hardware based pulse-width-modulator pins
+//
+// Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "basecmd.h" // alloc_oid
+#include "board/gpio.h" // struct gpio_pwm
+#include "command.h" // DECL_COMMAND
+#include "sched.h" // sched_timer
+
+struct pwm_out_s {
+    struct timer timer;
+    struct gpio_pwm pin;
+    uint32_t max_duration;
+    uint8_t value, default_value;
+};
+
+static uint8_t
+pwm_end_event(struct timer *timer)
+{
+    shutdown("Missed scheduling of next hard pwm event");
+}
+
+static uint8_t
+pwm_event(struct timer *timer)
+{
+    struct pwm_out_s *p = container_of(timer, struct pwm_out_s, timer);
+    gpio_pwm_write(p->pin, p->value);
+    if (p->value == p->default_value || !p->max_duration)
+        return SF_DONE;
+    p->timer.waketime += p->max_duration;
+    p->timer.func = pwm_end_event;
+    return SF_RESCHEDULE;
+}
+
+void
+command_config_pwm_out(uint32_t *args)
+{
+    struct pwm_out_s *p = alloc_oid(args[0], command_config_pwm_out, sizeof(*p));
+    p->default_value = args[3];
+    p->pin = gpio_pwm_setup(args[1], args[2], p->default_value);
+    p->max_duration = args[4];
+}
+DECL_COMMAND(command_config_pwm_out,
+             "config_pwm_out oid=%c pin=%u cycle_ticks=%u default_value=%c"
+             " max_duration=%u");
+
+void
+command_schedule_pwm_out(uint32_t *args)
+{
+    struct pwm_out_s *p = lookup_oid(args[0], command_config_pwm_out);
+    sched_del_timer(&p->timer);
+    p->timer.func = pwm_event;
+    p->timer.waketime = args[1];
+    p->value = args[2];
+    sched_timer(&p->timer);
+}
+DECL_COMMAND(command_schedule_pwm_out,
+             "schedule_pwm_out oid=%c clock=%u value=%c");
+
+static void
+pwm_shutdown(void)
+{
+    uint8_t i;
+    struct pwm_out_s *p;
+    foreach_oid(i, p, command_config_pwm_out) {
+        gpio_pwm_write(p->pin, p->default_value);
+    }
+}
+DECL_SHUTDOWN(pwm_shutdown);
+
+void
+command_set_pwm_out(uint32_t *args)
+{
+    gpio_pwm_setup(args[0], args[1], args[2]);
+}
+DECL_COMMAND(command_set_pwm_out, "set_pwm_out pin=%u cycle_ticks=%u value=%c");