From d3a09ff7f9a2fb497ba492398f4307c2df628a03 Mon Sep 17 00:00:00 2001
From: knolax <1339802534.kk@gmail.com>
Date: Thu, 7 Dec 2017 20:19:41 -0500
Subject: initial commit

---
 Makefile |   7 ++++
 skey.c   | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 Makefile
 create mode 100644 skey.c

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..5597d2f
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,7 @@
+obj-m := skey.o
+
+all:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
+
+clean:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
diff --git a/skey.c b/skey.c
new file mode 100644
index 0000000..834a6fe
--- /dev/null
+++ b/skey.c
@@ -0,0 +1,110 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/timer.h>
+/*
+ * Unsigned ints containing the BCM pin numbers for the pins used, __initdata
+ * helps with the loading and unloading of data in memory
+ */
+static __initdata unsigned int column_pins[10] = {10, 24, 23, 22, 27, 18, 17, 15, 14, 4};
+static __initdata unsigned int row_pins[3] = {3, 6, 5};
+/*
+ * GPIO labels
+ */
+static __initdata char * clabels[10] = {"C0", "C1", "C2", "C3", "C4", "C5", "C6", "C7", "C8", "C9",};
+static __initdata char * rlabels[3] = {"R0", "R1", "R2"};
+/*
+ * timer period in ms and timer struct
+ */
+static struct timer_list update_timer;
+static int update_period = 5000;
+/*
+ *This function is called every timer-period to actually read the keyboard
+ */
+static void skey_update (unsigned long unused) {
+	printk(KERN_INFO "skey: updated keyboard\n");
+	mod_timer(&update_timer, jiffies + msecs_to_jiffies(update_period));
+}
+/*
+ * This function is called when the module is loaded
+ * __init functions similar to __initdata
+ */
+static int  __init skey_init (void) {
+	printk(KERN_INFO "skey: module initiating...\n");
+	int i = 0;
+	//claims the column pins
+	while (i < 10) {
+		//checks to see if the gpios are valid
+		if (!gpio_is_valid(column_pins[i])) {
+			printk(KERN_ALERT "skey: column_pins[%d], BCM %d request invalid\n", i, column_pins[i]);
+			return -EINVAL;
+		}
+		//requests access of the GPIO
+		if (gpio_request_one(column_pins[i], GPIOF_DIR_IN ,clabels[i])) {
+			printk(KERN_ALERT "skey: column_pins[%d], BCM %d request failed\n", i, column_pins[i]);
+			return -EINVAL;
+		}
+		i++;
+	}
+	//ditto for row pins
+	int j = 0;
+	while (j < 3) {
+		//checks to see if the gpios are valid
+		if (!gpio_is_valid(row_pins[j])) {
+			printk(KERN_ALERT "skey: row_pins[%d], BCM %d request invalid\n", j, row_pins[j]);
+			return -EINVAL;
+		}
+		//requests access of the GPIO
+		if (gpio_request_one(row_pins[j], GPIOF_OUT_INIT_LOW ,rlabels[j])) {
+			printk(KERN_ALERT "skey: row_pins[%d], BCM %d request failed\n", j, row_pins[j]);
+			return -EINVAL;
+		}
+		j++;
+	}
+	//sets up timer for keyboard read function
+	setup_timer(&update_timer, skey_update, 0);
+	if (mod_timer(&update_timer, jiffies + msecs_to_jiffies(update_period))) {
+		printk(KERN_ALERT "skey: failed to set up timer\n");
+		return -EINVAL;
+	}
+	printk(KERN_INFO "skey: module finished initiating\n");
+	return 0;
+}
+/*
+ * This function is called when the module is unloaded
+ *
+ */
+static void __exit skey_exit (void) {
+	printk(KERN_INFO "skey: module exiting...\n");
+	//frees column and row pins
+	int i = 0;
+	while (i < 10) {
+		gpio_free(column_pins[i]);
+		i++;
+	}
+	int j = 0;
+	while (j < 3) {
+		gpio_free(row_pins[j]);
+		j++;
+	}
+	//deletes update timer
+	del_timer(&update_timer);
+	printk(KERN_INFO "skey: module exited\n");
+	return;
+}
+/*
+ * Registers the init and exit functions
+ */
+module_init(skey_init);
+module_exit(skey_exit);
+/*
+ * registers module metadata
+ */
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Haoran S. Diao <1339802534.kk@gmail.com>");
+MODULE_DESCRIPTION("Driver for the omnicom switch keyboard");
+/*
+ *this sets the name of device files used by this module, this is used
+ *when the kernel makes devices automatically
+ */
+MODULE_SUPPORTED_DEVICE("skeydev");
-- 
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