[PATCH 09/26] mfd: ab8500-debugfs: Provide a means for a user subscribe to IRQs
Lee Jones
lee.jones at linaro.org
Tue Jan 15 07:55:49 EST 2013
Allow users to subscribe to and view IRQ events live from debugfs.
Signed-off-by: Lee Jones <lee.jones at linaro.org>
---
drivers/mfd/ab8500-debugfs.c | 197 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 197 insertions(+)
diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index c4cb806..71df8e4 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -11,6 +11,9 @@
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
#include <linux/mfd/abx500.h>
#include <linux/mfd/abx500/ab8500.h>
@@ -18,6 +21,9 @@
static u32 debug_bank;
static u32 debug_address;
+static int irq_first;
+static int irq_last;
+
/**
* struct ab8500_reg_range
* @first: the first address of the range
@@ -354,6 +360,21 @@ static struct ab8500_prcmu_ranges debug_ranges[AB8500_NUM_BANKS] = {
},
};
+static irqreturn_t ab8500_debug_handler(int irq, void *data)
+{
+ char buf[16];
+ struct kobject *kobj = (struct kobject *)data;
+
+ /*
+ * This makes it possible to use poll for events (POLLPRI | POLLERR)
+ * from userspace on sysfs file named irq-<nr>
+ */
+ sprintf(buf, "irq-%d", irq);
+ sysfs_notify(kobj, NULL, buf);
+
+ return IRQ_HANDLED;
+}
+
static int ab8500_registers_print(struct seq_file *s, void *p)
{
struct device *dev = s->private;
@@ -519,6 +540,130 @@ static ssize_t ab8500_val_write(struct file *file,
return count;
}
+static int ab8500_subscribe_unsubscribe_print(struct seq_file *s, void *p)
+{
+ seq_printf(s, "%d\n", irq_first);
+
+ return 0;
+}
+
+static int ab8500_subscribe_unsubscribe_open(struct inode *inode,
+ struct file *file)
+{
+ return single_open(file, ab8500_subscribe_unsubscribe_print,
+ inode->i_private);
+}
+
+/*
+ * This function is used for all interrupts and will always print
+ * the same string. It is however this file sysfs_notify called on.
+ * Userspace should read this file and then poll. When an event occur
+ * the blocking poll will be released.
+ */
+static ssize_t show_irq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "irq\n");
+}
+
+static struct device_attribute *dev_attr[AB8500_NR_IRQS];
+static char *event_name[AB8500_NR_IRQS];
+
+static ssize_t ab8500_subscribe_write(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct device *dev = ((struct seq_file *)(file->private_data))->private;
+ char buf[32];
+ int buf_size;
+ unsigned long user_val;
+ int err;
+
+ /* Get userspace string and assure termination */
+ buf_size = min(count, (sizeof(buf)-1));
+ if (copy_from_user(buf, user_buf, buf_size))
+ return -EFAULT;
+ buf[buf_size] = 0;
+
+ err = strict_strtoul(buf, 0, &user_val);
+ if (err)
+ return -EINVAL;
+ if (user_val < irq_first) {
+ dev_err(dev, "debugfs error input < %d\n", irq_first);
+ return -EINVAL;
+ }
+ if (user_val > irq_last) {
+ dev_err(dev, "debugfs error input > %d\n", irq_last);
+ return -EINVAL;
+ }
+
+ /*
+ * This will create a sysfs file named irq-<nr> which userspace can
+ * use to select or poll and get the AB8500 events
+ */
+ dev_attr[user_val] = kmalloc(sizeof(struct device_attribute),
+ GFP_KERNEL);
+ event_name[user_val] = kmalloc(buf_size, GFP_KERNEL);
+ sprintf(event_name[user_val], "irq-%lu", user_val);
+ dev_attr[user_val]->show = show_irq;
+ dev_attr[user_val]->store = NULL;
+ dev_attr[user_val]->attr.name = event_name[user_val];
+ dev_attr[user_val]->attr.mode = S_IRUGO;
+ err = sysfs_create_file(&dev->kobj, &dev_attr[user_val]->attr);
+ if (err < 0) {
+ printk(KERN_ERR "sysfs_create_file failed %d\n", err);
+ return err;
+ }
+
+ err = request_threaded_irq(user_val, NULL, ab8500_debug_handler,
+ 0, "ab8500-debug", &dev->kobj);
+ if (err < 0) {
+ printk(KERN_ERR "request_threaded_irq failed %d, %lu\n",
+ err, user_val);
+ return err;
+ }
+
+ return buf_size;
+}
+
+static ssize_t ab8500_unsubscribe_write(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct device *dev = ((struct seq_file *)(file->private_data))->private;
+ char buf[32];
+ int buf_size;
+ unsigned long user_val;
+ int err;
+
+ /* Get userspace string and assure termination */
+ buf_size = min(count, (sizeof(buf)-1));
+ if (copy_from_user(buf, user_buf, buf_size))
+ return -EFAULT;
+ buf[buf_size] = 0;
+
+ err = strict_strtoul(buf, 0, &user_val);
+ if (err)
+ return -EINVAL;
+ if (user_val < irq_first) {
+ dev_err(dev, "debugfs error input < %d\n", irq_first);
+ return -EINVAL;
+ }
+ if (user_val > irq_last) {
+ dev_err(dev, "debugfs error input > %d\n", irq_last);
+ return -EINVAL;
+ }
+
+ free_irq(user_val, &dev->kobj);
+ kfree(event_name[user_val]);
+ kfree(dev_attr[user_val]);
+
+ if (dev_attr[user_val])
+ sysfs_remove_file(&dev->kobj, &dev_attr[user_val]->attr);
+
+ return buf_size;
+}
+
static const struct file_operations ab8500_bank_fops = {
.open = ab8500_bank_open,
.write = ab8500_bank_write,
@@ -546,17 +691,51 @@ static const struct file_operations ab8500_val_fops = {
.owner = THIS_MODULE,
};
+static const struct file_operations ab8500_subscribe_fops = {
+ .open = ab8500_subscribe_unsubscribe_open,
+ .write = ab8500_subscribe_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .owner = THIS_MODULE,
+};
+
+static const struct file_operations ab8500_unsubscribe_fops = {
+ .open = ab8500_subscribe_unsubscribe_open,
+ .write = ab8500_unsubscribe_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .owner = THIS_MODULE,
+};
+
static struct dentry *ab8500_dir;
static struct dentry *ab8500_reg_file;
static struct dentry *ab8500_bank_file;
static struct dentry *ab8500_address_file;
static struct dentry *ab8500_val_file;
+static struct dentry *ab8500_subscribe_file;
+static struct dentry *ab8500_unsubscribe_file;
static int __devinit ab8500_debug_probe(struct platform_device *plf)
{
debug_bank = AB8500_MISC;
debug_address = AB8500_REV_REG & 0x00FF;
+ irq_first = platform_get_irq_byname(plf, "IRQ_FIRST");
+ if (irq_first < 0) {
+ dev_err(&plf->dev, "First irq not found, err %d\n",
+ irq_first);
+ return irq_first;
+ }
+
+ irq_last = platform_get_irq_byname(plf, "IRQ_LAST");
+ if (irq_last < 0) {
+ dev_err(&plf->dev, "Last irq not found, err %d\n",
+ irq_last);
+ return irq_last;
+ }
+
ab8500_dir = debugfs_create_dir(AB8500_NAME_STRING, NULL);
if (!ab8500_dir)
goto exit_no_debugfs;
@@ -582,8 +761,26 @@ static int __devinit ab8500_debug_probe(struct platform_device *plf)
if (!ab8500_val_file)
goto exit_destroy_address;
+ ab8500_subscribe_file =
+ debugfs_create_file("irq-subscribe",
+ (S_IRUGO | S_IWUGO), ab8500_dir, &plf->dev,
+ &ab8500_subscribe_fops);
+ if (!ab8500_subscribe_file)
+ goto exit_destroy_val;
+
+ ab8500_unsubscribe_file =
+ debugfs_create_file("irq-unsubscribe",
+ (S_IRUGO | S_IWUGO), ab8500_dir, &plf->dev,
+ &ab8500_unsubscribe_fops);
+ if (!ab8500_unsubscribe_file)
+ goto exit_destroy_subscribe;
+
return 0;
+exit_destroy_subscribe:
+ debugfs_remove(ab8500_subscribe_file);
+exit_destroy_val:
+ debugfs_remove(ab8500_val_file);
exit_destroy_address:
debugfs_remove(ab8500_address_file);
exit_destroy_bank:
--
1.7.9.5
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