hosted: Consolidate common /dev/input code shared by the hiby targets

* Enable dynamic number of input devices, needed for bluetooth support

Change-Id: Ic2425834eb9b0fff298899ab45f3115ce1d95e91

firmware/target/hosted/button-devinput.c

@@ -0,0 +1,130 @@
+/***************************************************************************
+ *             __________               __   ___
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Copyright (C) 2017 Marcin Bukat
+ * Copyright (C) 2020 Solomon Peachy
+
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include <poll.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <linux/input.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "kernel.h"
+#include "sysfs.h"
+#include "button.h"
+#include "panic.h"
+
+#define NR_POLL_DESC    4
+
+static int num_devices = 0;
+static struct pollfd poll_fds[NR_POLL_DESC];
+
+void button_init_device(void)
+{
+    const char * const input_devs[NR_POLL_DESC] = {
+        "/dev/input/event0",
+        "/dev/input/event1",
+        "/dev/input/event2",
+        "/dev/input/event3",
+    };
+
+    for(int i = 0; i < NR_POLL_DESC; i++)
+    {
+        int fd = open(input_devs[i], O_RDONLY | O_CLOEXEC);
+
+        if(fd >= 0)
+        {
+            poll_fds[num_devices].fd = fd;
+            poll_fds[num_devices].events = POLLIN;
+            poll_fds[num_devices].revents = 0;
+            num_devices++;
+        }
+    }
+}
+
+void button_close_device(void)
+{
+    /* close descriptors */
+    for(int i = 0; i < num_devices; i++)
+    {
+        close(poll_fds[i].fd);
+    }
+    num_devices = 0;
+}
+
+int button_read_device(void)
+{
+    static int button_bitmap = 0;
+    struct input_event event;
+
+#if defined(BUTTON_SCROLL_BACK)
+    // FIXME TODO:  Make this work via HAVE_SCROLL_WHEEL instead
+
+    /* Wheel gives us press+release back to back, clear them after time elapses */
+    static long last_tick = 0;
+    if (button_bitmap & (BUTTON_SCROLL_BACK|BUTTON_SCROLL_FWD) &&
+        current_tick - last_tick >= 2)
+    {
+        button_bitmap &= ~(BUTTON_SCROLL_BACK|BUTTON_SCROLL_FWD);
+    }
+#endif
+
+    /* check if there are any events pending and process them */
+    while(poll(poll_fds, num_devices, 0))
+    {
+        for(int i = 0; i < num_devices; i++)
+        {
+            /* read only if non-blocking */
+            if(poll_fds[i].revents & POLLIN)
+            {
+                int size = read(poll_fds[i].fd, &event, sizeof(event));
+                if(size == (int)sizeof(event))
+                {
+                    int keycode = event.code;
+                    /* event.value == 0x10000 means press
+                     * event.value == 0 means release
+                     */
+                    bool press = event.value ? true : false;
+
+                    /* map linux event code to rockbox button bitmap */
+                    if(press)
+                    {
+                        button_bitmap |= button_map(keycode);
+                    }
+                    else
+                    {
+#if defined(BUTTON_SCROLL_BACK)
+                        /* Wheel gives us press+release back to back; ignore the release */
+                        int bmap = button_map(keycode) & ~(BUTTON_SCROLL_BACK|BUTTON_SCROLL_FWD);
+                        button_bitmap &= ~bmap;
+#else
+                        button_bitmap &= ~button_map(keycode);
+#endif
+                    }
+                }
+            }
+        }
+    }
+
+    return button_bitmap;
+}