1 files changed, 103 insertions, 14 deletions

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index c498b0fbbec8..154d959e8993 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -47,6 +47,7 @@ enum {
 struct gpio_mockup_line_status {
         int dir;
         int value;
+        int pull;
 };
 
 struct gpio_mockup_chip {
@@ -188,15 +189,56 @@ static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
         return irq_sim_irqnum(&chip->irqsim, offset);
 }
 
-static ssize_t gpio_mockup_event_write(struct file *file,
-                                       const char __user *usr_buf,
-                                       size_t size, loff_t *ppos)
+static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
+{
+        struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
+
+        __gpio_mockup_set(chip, offset, chip->lines[offset].pull);
+}
+
+static ssize_t gpio_mockup_debugfs_read(struct file *file,
+                                        char __user *usr_buf,
+                                        size_t size, loff_t *ppos)
 {
         struct gpio_mockup_dbgfs_private *priv;
         struct gpio_mockup_chip *chip;
         struct seq_file *sfile;
+        struct gpio_chip *gc;
+        char buf[3];
+        int val, rv;
+
+        if (*ppos != 0)
+                return 0;
+
+        sfile = file->private_data;
+        priv = sfile->private;
+        chip = priv->chip;
+        gc = &chip->gc;
+
+        val = gpio_mockup_get(gc, priv->offset);
+        snprintf(buf, sizeof(buf), "%d\n", val);
+
+        rv = copy_to_user(usr_buf, buf, sizeof(buf));
+        if (rv)
+                return rv;
+
+        return sizeof(buf) - 1;
+}
+
+static ssize_t gpio_mockup_debugfs_write(struct file *file,
+                                         const char __user *usr_buf,
+                                         size_t size, loff_t *ppos)
+{
+        struct gpio_mockup_dbgfs_private *priv;
+        int rv, val, curr, irq, irq_type;
+        struct gpio_mockup_chip *chip;
+        struct seq_file *sfile;
         struct gpio_desc *desc;
-        int rv, val;
+        struct gpio_chip *gc;
+        struct irq_sim *sim;
+
+        if (*ppos != 0)
+                return -EINVAL;
 
         rv = kstrtoint_from_user(usr_buf, size, 0, &val);
         if (rv)
@@ -206,24 +248,70 @@ static ssize_t gpio_mockup_event_write(struct file *file,
 
         sfile = file->private_data;
         priv = sfile->private;
-        desc = priv->desc;
         chip = priv->chip;
+        gc = &chip->gc;
+        desc = &gc->gpiodev->descs[priv->offset];
+        sim = &chip->irqsim;
+
+        mutex_lock(&chip->lock);
+
+        if (test_bit(FLAG_REQUESTED, &desc->flags) &&
+            !test_bit(FLAG_IS_OUT, &desc->flags)) {
+                curr = __gpio_mockup_get(chip, priv->offset);
+                if (curr == val)
+                        goto out;
 
-        gpiod_set_value_cansleep(desc, val);
-        irq_sim_fire(&chip->irqsim, priv->offset);
+                irq = irq_sim_irqnum(sim, priv->offset);
+                irq_type = irq_get_trigger_type(irq);
+
+                if ((val == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
+                    (val == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING)))
+                        irq_sim_fire(sim, priv->offset);
+        }
+
+        /* Change the value unless we're actively driving the line. */
+        if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
+            !test_bit(FLAG_IS_OUT, &desc->flags))
+                __gpio_mockup_set(chip, priv->offset, val);
+
+out:
+        chip->lines[priv->offset].pull = val;
+        mutex_unlock(&chip->lock);
 
         return size;
 }
 
-static int gpio_mockup_event_open(struct inode *inode, struct file *file)
+static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file)
 {
         return single_open(file, NULL, inode->i_private);
 }
 
-static const struct file_operations gpio_mockup_event_ops = {
+/*
+ * Each mockup chip is represented by a directory named after the chip's device
+ * name under /sys/kernel/debug/gpio-mockup/. Each line is represented by
+ * a file using the line's offset as the name under the chip's directory.
+ *
+ * Reading from the line's file yields the current *value*, writing to the
+ * line's file changes the current *pull*. Default pull for mockup lines is
+ * down.
+ *
+ * Examples:
+ * - when a line pulled down is requested in output mode and driven high, its
+ *   value will return to 0 once it's released
+ * - when the line is requested in output mode and driven high, writing 0 to
+ *   the corresponding debugfs file will change the pull to down but the
+ *   reported value will still be 1 until the line is released
+ * - line requested in input mode always reports the same value as its pull
+ *   configuration
+ * - when the line is requested in input mode and monitored for events, writing
+ *   the same value to the debugfs file will be a noop, while writing the
+ *   opposite value will generate a dummy interrupt with an appropriate edge
+ */
+static const struct file_operations gpio_mockup_debugfs_ops = {
         .owner = THIS_MODULE,
-        .open = gpio_mockup_event_open,
-        .write = gpio_mockup_event_write,
+        .open = gpio_mockup_debugfs_open,
+        .read = gpio_mockup_debugfs_read,
+        .write = gpio_mockup_debugfs_write,
         .llseek = no_llseek,
 };
 
@@ -258,7 +346,7 @@ static void gpio_mockup_debugfs_setup(struct device *dev,
                 priv->desc = &gc->gpiodev->descs[i];
 
                 evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
-                                             &gpio_mockup_event_ops);
+                                             &gpio_mockup_debugfs_ops);
                 if (IS_ERR_OR_NULL(evfile))
                         goto err;
         }
@@ -266,7 +354,7 @@ static void gpio_mockup_debugfs_setup(struct device *dev,
         return;
 
 err:
-        dev_err(dev, "error creating debugfs event files\n");
+        dev_err(dev, "error creating debugfs files\n");
 }
 
 static int gpio_mockup_name_lines(struct device *dev,
@@ -342,6 +430,7 @@ static int gpio_mockup_probe(struct platform_device *pdev)
         gc->direction_input = gpio_mockup_dirin;
         gc->get_direction = gpio_mockup_get_direction;
         gc->to_irq = gpio_mockup_to_irq;
+        gc->free = gpio_mockup_free;
 
         chip->lines = devm_kcalloc(dev, gc->ngpio,
                                    sizeof(*chip->lines), GFP_KERNEL);
@@ -415,7 +504,7 @@ static int __init gpio_mockup_init(void)
                         return -EINVAL;
         }
 
-        gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
+        gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL);
         if (IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
                 gpio_mockup_err("error creating debugfs directory\n");