Re: [PATCH 7/8] smiapp: Add support for flash, lens and EEPROM devices

[Pavel Machek]

Hi!

> > This is quite a lot of boilerplate for that. Would it make sense to
> > provide helper function at least for this?
> 
> Yes. I've been thinking of having helper functions for notifiers and
> sub-notifiers. Most of the receiver drivers are implementing exactly the
> same thing but with different twists (read: bugs).

Perhaps something like this is a starting point?

                                                                        Pavel

commit 22d722b7ee7cb437ae2013fa83a215f91151621c
Author: Pavel <pa...@ucw.cz>
Date:   Sat Jun 17 14:14:08 2017 +0200

    Subdev support for et8ek8.
    
    Subdev code is ready for moving to some other place -- this is really
    common code.
    
    Signed-off-by: Pavel Machek <pa...@ucw.cz>

diff --git a/drivers/media/i2c/et8ek8/et8ek8_driver.c 
b/drivers/media/i2c/et8ek8/et8ek8_driver.c
index 05b9bd9..a6899fc 100644
--- a/drivers/media/i2c/et8ek8/et8ek8_driver.c
+++ b/drivers/media/i2c/et8ek8/et8ek8_driver.c
@@ -32,13 +32,90 @@
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/sort.h>
-#include <linux/v4l2-mediabus.h>
 
+#include <media/v4l2-async.h>
+#include <linux/v4l2-mediabus.h>
 #include <media/media-entity.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-subdev.h>
 
+static int simple_subdev_notifier_bound(struct v4l2_async_notifier *notifier,
+                                       struct v4l2_subdev *sd,
+                                       struct v4l2_async_subdev *asd)
+{
+       return 0;
+}
+
+static int simple_subdev_notifier_complete(
+       struct v4l2_async_notifier *notifier)
+{
+       struct v4l2_async_notifier_simple *notifier_s =
+               container_of(notifier, struct v4l2_async_notifier_simple, 
notifier);
+
+       return v4l2_device_register_subdev_nodes(notifier_s->v4l2_dev);
+}
+
+static inline int v4l2_simple_subnotifier_register(struct v4l2_subdev *subdev,
+                                    struct v4l2_async_notifier_simple 
*notifier_s)
+{
+       struct v4l2_async_notifier *notifier = &notifier_s->notifier;
+       int rval;
+       if (!notifier->num_subdevs)
+               return 0;
+
+       notifier_s->v4l2_dev = subdev->v4l2_dev;
+       notifier->bound = simple_subdev_notifier_bound;
+       notifier->complete = simple_subdev_notifier_complete;
+       rval = v4l2_async_subnotifier_register(subdev, notifier);
+       return rval;
+}
+
+static inline int simple_subdev_probe(struct device *dev,
+                                     struct v4l2_async_notifier *notifier)
+{
+       static const char *props[] = { "flash", "lens", "eeprom" };
+       unsigned int i;
+       const int max_subdevs = 3;
+       
+       notifier->subdevs =
+               devm_kcalloc(dev, max_subdevs,
+                            sizeof(struct v4l2_async_subdev *), GFP_KERNEL);
+       if (!notifier->subdevs)
+               return -ENOMEM;
+
+       for (i = 0; i < ARRAY_SIZE(props); i++) {
+               struct device_node *node;
+               unsigned int j = 0;
+
+               while ((node = of_parse_phandle(dev->of_node, props[i], j++))) {
+                       struct v4l2_async_subdev **asd =
+                                &notifier->subdevs[
+                                        notifier->num_subdevs];
+
+                       if (WARN_ON(notifier->num_subdevs >= max_subdevs)) {
+                               of_node_put(node);
+                               return 0;
+                       }
+
+                       *asd = devm_kzalloc(
+                               dev, sizeof(struct v4l2_async_subdev),
+                               GFP_KERNEL);
+                       if (!*asd) {
+                               of_node_put(node);
+                               return 0;
+                       }
+
+                       (*asd)->match.fwnode.fwnode = of_fwnode_handle(node);
+                       (*asd)->match_type = V4L2_ASYNC_MATCH_FWNODE;
+                       notifier->num_subdevs++;
+
+                       of_node_put(node);
+               }
+       }
+       return 0;
+}
+
 #include "et8ek8_reg.h"
 
 #define ET8EK8_NAME            "et8ek8"
@@ -67,6 +144,8 @@ struct et8ek8_sensor {
 
        struct mutex power_lock;
        int power_count;
+
+       struct v4l2_async_notifier_simple notifier_s;
 };
 
 #define to_et8ek8_sensor(sd)   container_of(sd, struct et8ek8_sensor, subdev)
@@ -1510,6 +1589,8 @@ et8ek8_registered(struct v4l2_subdev *subdev)
                goto err_file;
        }
 
+       v4l2_simple_subnotifier_register(subdev, &sensor->notifier_s);
+       
        __et8ek8_get_pad_format(sensor, NULL, 0, V4L2_SUBDEV_FORMAT_ACTIVE);
 
        return 0;
@@ -1680,6 +1761,8 @@ static int et8ek8_probe(struct i2c_client *client,
        if (ret < 0)
                goto err_entity;
 
+       simple_subdev_probe(dev, &sensor->notifier_s.notifier);
+
        dev_dbg(dev, "initialized!\n");
 
        return 0;
diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index f7e2a1a..63bcf80 100644
--- a/include/media/v4l2-async.h
+++ b/include/media/v4l2-async.h
@@ -104,6 +104,11 @@ struct v4l2_async_notifier {
                       struct v4l2_async_subdev *asd);
 };
 
+struct v4l2_async_notifier_simple {
+       struct v4l2_async_notifier notifier;
+       struct v4l2_device * v4l2_dev;
+};
+
 /**
  * v4l2_async_notifier_register - registers a subdevice asynchronous 
subnotifier
  *


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) 
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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