Add fbatt

4 files changed, 134 insertions, 1 deletions

diff --git a/bin/.gitignore b/bin/.gitignore
index a85824f1..c193de65 100644
--- a/bin/.gitignore
+++ b/bin/.gitignore
@@ -11,5 +11,6 @@ klon
 typo
 watch
 bri
+fbatt
 fbclock
 gfxx
diff --git a/bin/Makefile b/bin/Makefile
index 6a4902cc..52bca4d4 100644
--- a/bin/Makefile
+++ b/bin/Makefile
@@ -1,6 +1,6 @@
 ANY_BINS = atch dtch hnel pbcopy pbd pbpaste wake xx
 BSD_BINS = jrp klon typo watch
-LIN_BINS = bri fbclock gfxx
+LIN_BINS = bri fbatt fbclock gfxx
 ALL_BINS = $(ANY_BINS) $(BSD_BINS) $(LIN_BINS)
 
 CFLAGS += -Wall -Wextra -Wpedantic
diff --git a/bin/README b/bin/README
index b476d085..9a990d71 100644
--- a/bin/README
+++ b/bin/README
@@ -19,6 +19,11 @@ with ^Q.
     dtch a nvim & disown
     atch a
 
+                                 fbatt
+
+Battery charge indicator panel for the Linux Framebuffer through
+/sys/class/power_supply.
+
                                 fbclock
 
 Clock panel for the Linux framebuffer. Renders PSF2 bitmap fonts.
diff --git a/bin/fbatt.c b/bin/fbatt.c
new file mode 100644
index 00000000..5b0180ea
--- /dev/null
+++ b/bin/fbatt.c
@@ -0,0 +1,127 @@
+/* Copyright (c) 2018, June McEnroe <programble@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <dirent.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+static const char *CLASS = "/sys/class/power_supply";
+
+static const uint32_t RIGHT  = 5 * 8 + 1; // fbclock width.
+static const uint32_t WIDTH  = 8;
+static const uint32_t HEIGHT = 16;
+
+static const uint32_t BG     = 0x1D2021;
+static const uint32_t BORDER = 0xA99A84;
+static const uint32_t GRAY   = 0x938374;
+static const uint32_t YELLOW = 0xD89A22;
+static const uint32_t RED    = 0xCC241D;
+
+int main() {
+    int error;
+
+    DIR *dir = opendir(CLASS);
+    if (!dir) err(EX_OSFILE, "%s", CLASS);
+
+    FILE *chargeFull = NULL;
+    FILE *chargeNow = NULL;
+
+    const struct dirent *entry;
+    while (NULL != (errno = 0, entry = readdir(dir))) {
+        if (entry->d_name[0] == '.') continue;
+
+        error = chdir(CLASS);
+        if (error) err(EX_IOERR, "%s", CLASS);
+
+        error = chdir(entry->d_name);
+        if (error) err(EX_IOERR, "%s/%s", CLASS, entry->d_name);
+
+        chargeFull = fopen("charge_full", "r");
+        chargeNow = fopen("charge_now", "r");
+        if (chargeFull && chargeNow) break;
+    }
+    if (!chargeFull || !chargeNow) {
+        if (errno) err(EX_IOERR, "%s", CLASS);
+        errx(EX_CONFIG, "empty %s", CLASS);
+    }
+    closedir(dir);
+
+    const char *path = getenv("FRAMEBUFFER");
+    if (!path) path = "/dev/fb0";
+
+    int fb = open(path, O_RDWR);
+    if (fb < 0) err(EX_OSFILE, "%s", path);
+
+    struct fb_var_screeninfo info;
+    error = ioctl(fb, FBIOGET_VSCREENINFO, &info);
+    if (error) err(EX_IOERR, "%s", path);
+
+    size_t size = 4 * info.xres * info.yres;
+    uint32_t *buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
+    if (buf == MAP_FAILED) err(EX_IOERR, "%s", path);
+
+    for (;;) {
+        int match;
+
+        rewind(chargeFull);
+        fflush(chargeFull);
+        uint32_t full;
+        match = fscanf(chargeFull, "%u", &full);
+        if (match == EOF) err(EX_IOERR, "charge_full");
+        if (match < 1) errx(EX_DATAERR, "charge_full");
+
+        rewind(chargeNow);
+        fflush(chargeNow);
+        uint32_t now;
+        match = fscanf(chargeNow, "%u", &now);
+        if (match == EOF) err(EX_IOERR, "charge_now");
+        if (match < 1) errx(EX_DATAERR, "charge_now");
+
+        uint32_t percent = 100 * now / full;
+        uint32_t height = 16 * now / full;
+
+        for (int i = 0; i < 60; ++i, sleep(1)) {
+            uint32_t left = info.xres - RIGHT - WIDTH;
+
+            for (uint32_t y = 0; y <= HEIGHT; ++y) {
+                buf[y * info.xres + left - 1] = BORDER;
+                buf[y * info.xres + left + WIDTH] = BORDER;
+            }
+            for (uint32_t x = left; x < left + WIDTH; ++x) {
+                buf[HEIGHT * info.xres + x] = BORDER;
+            }
+
+            for (uint32_t y = 0; y < HEIGHT; ++y) {
+                for (uint32_t x = left; x < left + WIDTH; ++x) {
+                    buf[y * info.xres + x] =
+                        (HEIGHT - 1 - y > height) ? BG
+                        : (percent <= 10) ? RED
+                        : (percent <= 30) ? YELLOW
+                        : GRAY;
+                }
+            }
+        }
+    }
+}