1 files changed, 141 insertions, 0 deletions
diff --git a/src/atsamd/gpio.c b/src/atsamd/gpio.c
new file mode 100644
index 00000000..045dc003
--- /dev/null
+++ b/src/atsamd/gpio.c
@@ -0,0 +1,141 @@
+// samd21 gpio functions
+//
+// Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <string.h> // ffs
+#include "board/irq.h" // irq_save
+#include "command.h" // shutdown
+#include "gpio.h" // gpio_out_setup
+#include "internal.h" // gpio_peripheral
+#include "samd21.h" // PORT
+#include "sched.h" // sched_shutdown
+
+
+/****************************************************************
+ * Pin multiplexing
+ ****************************************************************/
+
+void
+gpio_peripheral(uint32_t gpio, char ptype, int32_t pull_up)
+{
+    uint32_t bank = GPIO2PORT(gpio), bit = gpio % 32;
+    PortGroup *pg = &PORT->Group[bank];
+    if (ptype) {
+        volatile uint8_t *pmux = &pg->PMUX[bit/2].reg;
+        uint8_t shift = (bit & 1) ? 4 : 0, mask = ~(0xf << shift);
+        *pmux = (*pmux & mask) | ((ptype - 'A') << shift);
+    }
+    if (pull_up) {
+        if (pull_up > 0)
+            pg->OUTSET.reg = (1<<bit);
+        else
+            pg->OUTCLR.reg = (1<<bit);
+    }
+
+    pg->PINCFG[bit].reg = ((ptype ? PORT_PINCFG_PMUXEN : 0)
+                           | (pull_up ? PORT_PINCFG_PULLEN : 0));
+}
+
+
+/****************************************************************
+ * General Purpose Input Output (GPIO) pins
+ ****************************************************************/
+
+#define NUM_PORT 2
+
+struct gpio_out
+gpio_out_setup(uint8_t pin, uint8_t val)
+{
+    if (GPIO2PORT(pin) >= NUM_PORT)
+        goto fail;
+    PortGroup *pg = &PORT->Group[GPIO2PORT(pin)];
+    struct gpio_out g = { .regs=pg, .bit=GPIO2BIT(pin) };
+    gpio_out_reset(g, val);
+    return g;
+fail:
+    shutdown("Not an output pin");
+}
+
+static void
+set_pincfg(PortGroup *pg, uint32_t bit, uint8_t cfg)
+{
+    pg->PINCFG[ffs(bit)-1].reg = cfg;
+}
+
+void
+gpio_out_reset(struct gpio_out g, uint8_t val)
+{
+    PortGroup *pg = g.regs;
+    irqstatus_t flag = irq_save();
+    if (val)
+        pg->OUTSET.reg = g.bit;
+    else
+        pg->OUTCLR.reg = g.bit;
+    pg->DIRSET.reg = g.bit;
+    set_pincfg(pg, g.bit, 0);
+    irq_restore(flag);
+}
+
+void
+gpio_out_toggle_noirq(struct gpio_out g)
+{
+    PortGroup *pg = g.regs;
+    pg->OUTTGL.reg = g.bit;
+}
+
+void
+gpio_out_toggle(struct gpio_out g)
+{
+    gpio_out_toggle_noirq(g);
+}
+
+void
+gpio_out_write(struct gpio_out g, uint8_t val)
+{
+    PortGroup *pg = g.regs;
+    if (val)
+        pg->OUTSET.reg = g.bit;
+    else
+        pg->OUTCLR.reg = g.bit;
+}
+
+
+struct gpio_in
+gpio_in_setup(uint8_t pin, int8_t pull_up)
+{
+    if (GPIO2PORT(pin) >= NUM_PORT)
+        goto fail;
+    PortGroup *pg = &PORT->Group[GPIO2PORT(pin)];
+    struct gpio_in g = { .regs=pg, .bit=GPIO2BIT(pin) };
+    gpio_in_reset(g, pull_up);
+    return g;
+fail:
+    shutdown("Not an input pin");
+}
+
+void
+gpio_in_reset(struct gpio_in g, int8_t pull_up)
+{
+    PortGroup *pg = g.regs;
+    irqstatus_t flag = irq_save();
+    uint32_t cfg = PORT_PINCFG_INEN;
+    if (pull_up) {
+        cfg |= PORT_PINCFG_PULLEN;
+        if (pull_up > 0)
+            pg->OUTSET.reg = g.bit;
+        else
+            pg->OUTCLR.reg = g.bit;
+    }
+    set_pincfg(pg, g.bit, cfg);
+    pg->DIRCLR.reg = g.bit;
+    irq_restore(flag);
+}
+
+uint8_t
+gpio_in_read(struct gpio_in g)
+{
+    PortGroup *pg = g.regs;
+    return !!(pg->IN.reg & g.bit);
+}