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Subject[PATCH 2/2] MFD: ab8500-debugfs irq support
Date
This patch makes it possible to listned for ab8500 interrupts
from userspace. A sysfs file is dynamically created
and sysfs_notify is called when an interrupt occurs. This will
make the userspace poll call to be released.

Signed-off-by: Mattias Wallin <mattias.wallin@stericsson.com>
---
drivers/mfd/ab8500-debugfs.c | 236 +++++++++++++++++++++++++++++++++++++++++-
1 files changed, 231 insertions(+), 5 deletions(-)
diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index dfdc76e..8d5e30a 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -10,6 +10,9 @@
#include <linux/fs.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/ab8500.h>
@@ -17,6 +20,13 @@
static u32 debug_bank;
static u32 debug_address;

+static int irq_first;
+static int irq_last;
+static u32 irq_count[AB8500_NR_IRQS];
+
+static struct device_attribute *dev_attr[AB8500_NR_IRQS];
+static char *event_name[AB8500_NR_IRQS];
+
/**
* struct ab8500_reg_range
* @first: the first address of the range
@@ -44,7 +54,7 @@ struct ab8500_i2c_ranges {
#define AB8500_NAME_STRING "ab8500"
#define AB8500_NUM_BANKS 22

-#define AB8500_REV_REG 0x80
+#define AB8500_REV_REG 0x80

static struct ab8500_i2c_ranges debug_ranges[AB8500_NUM_BANKS] = {
[0x0] = {
@@ -353,6 +363,24 @@ static struct ab8500_i2c_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;
+ unsigned int irq_abb = irq - irq_first;
+
+ if (irq_abb < AB8500_NR_IRQS)
+ irq_count[irq_abb]++;
+ /*
+ * This makes it possible to use poll for events (POLLPRI | POLLERR)
+ * from userspace on sysfs file named <irq-nr>
+ */
+ sprintf(buf, "%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;
@@ -382,8 +410,10 @@ static int ab8500_registers_print(struct seq_file *s, void *p)
reg, value);
if (err < 0) {
dev_err(dev, "seq_printf overflow\n");
- /* Error is not returned here since
- * the output is wanted in any case */
+ /*
+ * Error is not returned here since
+ * the output is wanted in any case
+ */
return 0;
}
}
@@ -537,6 +567,152 @@ static ssize_t ab8500_val_write(struct file *file,
return buf_size;
}

+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);
+}
+
+/*
+ * Userspace should use poll() on this file. When an event occur
+ * the blocking poll will be released.
+ */
+static ssize_t show_irq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ unsigned long name;
+ unsigned int irq_index;
+ int err;
+
+ err = strict_strtoul(attr->attr.name, 0, &name);
+ if (err)
+ return err;
+
+ irq_index = name - irq_first;
+ if (irq_index >= AB8500_NR_IRQS)
+ return -EINVAL;
+ else
+ return sprintf(buf, "%u\n", irq_count[irq_index]);
+}
+
+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;
+ unsigned int irq_index;
+
+ /* 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;
+ }
+
+ irq_index = user_val - irq_first;
+ if (irq_index >= AB8500_NR_IRQS)
+ 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[irq_index] = kmalloc(sizeof(struct device_attribute),
+ GFP_KERNEL);
+ event_name[irq_index] = kmalloc(buf_size, GFP_KERNEL);
+ sprintf(event_name[irq_index], "%lu", user_val);
+ dev_attr[irq_index]->show = show_irq;
+ dev_attr[irq_index]->store = NULL;
+ dev_attr[irq_index]->attr.name = event_name[irq_index];
+ dev_attr[irq_index]->attr.mode = S_IRUGO;
+ err = sysfs_create_file(&dev->kobj, &dev_attr[irq_index]->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,
+ IRQF_SHARED | IRQF_NO_SUSPEND, "ab8500-debug", &dev->kobj);
+ if (err < 0) {
+ printk(KERN_ERR "request_threaded_irq failed %d, %lu\n",
+ err, user_val);
+ sysfs_remove_file(&dev->kobj, &dev_attr[irq_index]->attr);
+ 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;
+ unsigned int irq_index;
+
+ /* 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;
+ }
+
+ irq_index = user_val - irq_first;
+ if (irq_index >= AB8500_NR_IRQS)
+ return -EINVAL;
+
+ /* Set irq count to 0 when unsubscribe */
+ irq_count[irq_index] = 0;
+
+ if (dev_attr[irq_index])
+ sysfs_remove_file(&dev->kobj, &dev_attr[irq_index]->attr);
+
+
+ free_irq(user_val, &dev->kobj);
+ kfree(event_name[irq_index]);
+ kfree(dev_attr[irq_index]);
+
+ return buf_size;
+}
+
static const struct file_operations ab8500_bank_fops = {
.open = ab8500_bank_open,
.write = ab8500_bank_write,
@@ -564,17 +740,51 @@ 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;
@@ -600,8 +810,24 @@ 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:
@@ -631,8 +857,8 @@ static struct platform_driver ab8500_debug_driver = {
.name = "ab8500-debug",
.owner = THIS_MODULE,
},
- .probe = ab8500_debug_probe,
- .remove = __devexit_p(ab8500_debug_remove)
+ .probe = ab8500_debug_probe,
+ .remove = __devexit_p(ab8500_debug_remove)
};

static int __init ab8500_debug_init(void)
--
1.7.2.2


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