Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 248 insertions, 0 deletions

diff --git a/drivers/char/nwbutton.c b/drivers/char/nwbutton.c
new file mode 100644
index 000000000000..4083b781adbf
--- /dev/null
+++ b/drivers/char/nwbutton.c
@@ -0,0 +1,248 @@
+/*
+ *      NetWinder Button Driver-
+ *      Copyright (C) Alex Holden <alex@linuxhacker.org> 1998, 1999.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/timer.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+
+#include <asm/uaccess.h>
+#include <asm/irq.h>
+#include <asm/mach-types.h>
+
+#define __NWBUTTON_C            /* Tell the header file who we are */
+#include "nwbutton.h"
+
+static int button_press_count;          /* The count of button presses */
+static struct timer_list button_timer;  /* Times for the end of a sequence */ 
+static DECLARE_WAIT_QUEUE_HEAD(button_wait_queue); /* Used for blocking read */
+static char button_output_buffer[32];   /* Stores data to write out of device */
+static int bcount;                      /* The number of bytes in the buffer */
+static int bdelay = BUTTON_DELAY;       /* The delay, in jiffies */
+static struct button_callback button_callback_list[32]; /* The callback list */
+static int callback_count;              /* The number of callbacks registered */
+static int reboot_count = NUM_PRESSES_REBOOT; /* Number of presses to reboot */
+
+/*
+ * This function is called by other drivers to register a callback function
+ * to be called when a particular number of button presses occurs.
+ * The callback list is a static array of 32 entries (I somehow doubt many
+ * people are ever going to want to register more than 32 different actions
+ * to be performed by the kernel on different numbers of button presses ;).
+ * However, if an attempt to register a 33rd entry (perhaps a stuck loop
+ * somewhere registering the same entry over and over?) it will fail to
+ * do so and return -ENOMEM. If an attempt is made to register a null pointer,
+ * it will fail to do so and return -EINVAL.
+ * Because callbacks can be unregistered at random the list can become
+ * fragmented, so we need to search through the list until we find the first
+ * free entry.
+ *
+ * FIXME: Has anyone spotted any locking functions int his code recently ??
+ */
+
+int button_add_callback (void (*callback) (void), int count)
+{
+        int lp = 0;
+        if (callback_count == 32) {
+                return -ENOMEM;
+        }
+        if (!callback) {
+                return -EINVAL;
+        }
+        callback_count++;
+        for (; (button_callback_list [lp].callback); lp++);
+        button_callback_list [lp].callback = callback;
+        button_callback_list [lp].count = count;
+        return 0;
+}
+
+/*
+ * This function is called by other drivers to deregister a callback function.
+ * If you attempt to unregister a callback which does not exist, it will fail
+ * with -EINVAL. If there is more than one entry with the same address,
+ * because it searches the list from end to beginning, it will unregister the
+ * last one to be registered first (FILO- First In Last Out).
+ * Note that this is not neccessarily true if the entries are not submitted
+ * at the same time, because another driver could have unregistered a callback
+ * between the submissions creating a gap earlier in the list, which would
+ * be filled first at submission time.
+ */
+
+int button_del_callback (void (*callback) (void))
+{
+        int lp = 31;
+        if (!callback) {
+                return -EINVAL;
+        }
+        while (lp >= 0) {
+                if ((button_callback_list [lp].callback) == callback) {
+                        button_callback_list [lp].callback = NULL;
+                        button_callback_list [lp].count = 0;
+                        callback_count--;
+                        return 0;
+                };
+                lp--;
+        };
+        return -EINVAL;
+}
+
+/*
+ * This function is called by button_sequence_finished to search through the
+ * list of callback functions, and call any of them whose count argument
+ * matches the current count of button presses. It starts at the beginning
+ * of the list and works up to the end. It will refuse to follow a null
+ * pointer (which should never happen anyway).
+ */
+
+static void button_consume_callbacks (int bpcount)
+{
+        int lp = 0;
+        for (; lp <= 31; lp++) {
+                if ((button_callback_list [lp].count) == bpcount) {
+                        if (button_callback_list [lp].callback) {
+                                button_callback_list[lp].callback();
+                        }
+                }
+        }
+}
+
+/* 
+ * This function is called when the button_timer times out.
+ * ie. When you don't press the button for bdelay jiffies, this is taken to
+ * mean you have ended the sequence of key presses, and this function is
+ * called to wind things up (write the press_count out to /dev/button, call
+ * any matching registered function callbacks, initiate reboot, etc.).
+ */
+
+static void button_sequence_finished (unsigned long parameters)
+{
+#ifdef CONFIG_NWBUTTON_REBOOT           /* Reboot using button is enabled */
+        if (button_press_count == reboot_count) {
+                kill_proc (1, SIGINT, 1);       /* Ask init to reboot us */
+        }
+#endif /* CONFIG_NWBUTTON_REBOOT */
+        button_consume_callbacks (button_press_count);
+        bcount = sprintf (button_output_buffer, "%d\n", button_press_count);
+        button_press_count = 0;         /* Reset the button press counter */
+        wake_up_interruptible (&button_wait_queue);
+}
+
+/* 
+ *  This handler is called when the orange button is pressed (GPIO 10 of the
+ *  SuperIO chip, which maps to logical IRQ 26). If the press_count is 0,
+ *  this is the first press, so it starts a timer and increments the counter.
+ *  If it is higher than 0, it deletes the old timer, starts a new one, and
+ *  increments the counter.
+ */ 
+
+static irqreturn_t button_handler (int irq, void *dev_id, struct pt_regs *regs)
+{
+        if (button_press_count) {
+                del_timer (&button_timer);
+        }
+        button_press_count++;
+        init_timer (&button_timer);
+        button_timer.function = button_sequence_finished;
+        button_timer.expires = (jiffies + bdelay);
+        add_timer (&button_timer);
+
+        return IRQ_HANDLED;
+}
+
+/*
+ * This function is called when a user space program attempts to read
+ * /dev/nwbutton. It puts the device to sleep on the wait queue until
+ * button_sequence_finished writes some data to the buffer and flushes
+ * the queue, at which point it writes the data out to the device and
+ * returns the number of characters it has written. This function is
+ * reentrant, so that many processes can be attempting to read from the
+ * device at any one time.
+ */
+
+static int button_read (struct file *filp, char __user *buffer,
+                        size_t count, loff_t *ppos)
+{
+        interruptible_sleep_on (&button_wait_queue);
+        return (copy_to_user (buffer, &button_output_buffer, bcount))
+                 ? -EFAULT : bcount;
+}
+
+/* 
+ * This structure is the file operations structure, which specifies what
+ * callbacks functions the kernel should call when a user mode process
+ * attempts to perform these operations on the device.
+ */
+
+static struct file_operations button_fops = {
+        .owner          = THIS_MODULE,
+        .read           = button_read,
+};
+
+/* 
+ * This structure is the misc device structure, which specifies the minor
+ * device number (158 in this case), the name of the device (for /proc/misc),
+ * and the address of the above file operations structure.
+ */
+
+static struct miscdevice button_misc_device = {
+        BUTTON_MINOR,
+        "nwbutton",
+        &button_fops,
+};
+
+/*
+ * This function is called to initialise the driver, either from misc.c at
+ * bootup if the driver is compiled into the kernel, or from init_module
+ * below at module insert time. It attempts to register the device node
+ * and the IRQ and fails with a warning message if either fails, though
+ * neither ever should because the device number and IRQ are unique to
+ * this driver.
+ */
+
+static int __init nwbutton_init(void)
+{
+        if (!machine_is_netwinder())
+                return -ENODEV;
+
+        printk (KERN_INFO "NetWinder Button Driver Version %s (C) Alex Holden "
+                        "<alex@linuxhacker.org> 1998.\n", VERSION);
+
+        if (misc_register (&button_misc_device)) {
+                printk (KERN_WARNING "nwbutton: Couldn't register device 10, "
+                                "%d.\n", BUTTON_MINOR);
+                return -EBUSY;
+        }
+
+        if (request_irq (IRQ_NETWINDER_BUTTON, button_handler, SA_INTERRUPT,
+                        "nwbutton", NULL)) {
+                printk (KERN_WARNING "nwbutton: IRQ %d is not free.\n",
+                                IRQ_NETWINDER_BUTTON);
+                misc_deregister (&button_misc_device);
+                return -EIO;
+        }
+        return 0;
+}
+
+static void __exit nwbutton_exit (void) 
+{
+        free_irq (IRQ_NETWINDER_BUTTON, NULL);
+        misc_deregister (&button_misc_device);
+}
+
+
+MODULE_AUTHOR("Alex Holden");
+MODULE_LICENSE("GPL");
+
+module_init(nwbutton_init);
+module_exit(nwbutton_exit);