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SubjectRe: [PATCH v2 1/5] media: cec-notifier: Get notifier by device and connector name
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Hi Sean,

On 18/05/2018 17:48, Sean Paul wrote:
> On Fri, May 18, 2018 at 03:05:00PM +0200, Neil Armstrong wrote:
>> In non device-tree world, we can need to get the notifier by the driver
>> name directly and eventually defer probe if not yet created.
>>
>> This patch adds a variant of the get function by using the device name
>> instead and will not create a notifier if not yet created.
>>
>> But the i915 driver exposes at least 2 HDMI connectors, this patch also
>> adds the possibility to add a connector name tied to the notifier device
>> to form a tuple and associate different CEC controllers for each HDMI
>> connectors.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
>
> Hi Neil,
> Thanks for posting these!
>
>> ---
>> drivers/media/cec/cec-notifier.c | 11 ++++++++---
>> include/media/cec-notifier.h | 27 ++++++++++++++++++++++++---
>> 2 files changed, 32 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c
>> index 16dffa0..dd2078b 100644
>> --- a/drivers/media/cec/cec-notifier.c
>> +++ b/drivers/media/cec/cec-notifier.c
>> @@ -21,6 +21,7 @@ struct cec_notifier {
>> struct list_head head;
>> struct kref kref;
>> struct device *dev;
>> + const char *conn;
>> struct cec_adapter *cec_adap;
>> void (*callback)(struct cec_adapter *adap, u16 pa);
>>
>> @@ -30,13 +31,14 @@ struct cec_notifier {
>> static LIST_HEAD(cec_notifiers);
>> static DEFINE_MUTEX(cec_notifiers_lock);
>>
>> -struct cec_notifier *cec_notifier_get(struct device *dev)
>> +struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
>> {
>> struct cec_notifier *n;
>>
>> mutex_lock(&cec_notifiers_lock);
>> list_for_each_entry(n, &cec_notifiers, head) {
>> - if (n->dev == dev) {
>> + if (n->dev == dev &&
>> + (!conn || !strcmp(n->conn, conn))) {
>> kref_get(&n->kref);
>> mutex_unlock(&cec_notifiers_lock);
>> return n;
>> @@ -46,6 +48,8 @@ struct cec_notifier *cec_notifier_get(struct device *dev)
>> if (!n)
>> goto unlock;
>> n->dev = dev;
>> + if (conn)
>> + n->conn = kstrdup(conn, GFP_KERNEL);
>> n->phys_addr = CEC_PHYS_ADDR_INVALID;
>> mutex_init(&n->lock);
>> kref_init(&n->kref);
>> @@ -54,7 +58,7 @@ struct cec_notifier *cec_notifier_get(struct device *dev)
>> mutex_unlock(&cec_notifiers_lock);
>> return n;
>> }
>> -EXPORT_SYMBOL_GPL(cec_notifier_get);
>> +EXPORT_SYMBOL_GPL(cec_notifier_get_conn);
>>
>> static void cec_notifier_release(struct kref *kref)
>> {
>> @@ -62,6 +66,7 @@ static void cec_notifier_release(struct kref *kref)
>> container_of(kref, struct cec_notifier, kref);
>>
>> list_del(&n->head);
>> + kfree(n->conn);
>> kfree(n);
>> }
>>
>> diff --git a/include/media/cec-notifier.h b/include/media/cec-notifier.h
>> index cf0add7..814eeef 100644
>> --- a/include/media/cec-notifier.h
>> +++ b/include/media/cec-notifier.h
>> @@ -20,8 +20,10 @@ struct cec_notifier;
>> #if IS_REACHABLE(CONFIG_CEC_CORE) && IS_ENABLED(CONFIG_CEC_NOTIFIER)
>>
>> /**
>> - * cec_notifier_get - find or create a new cec_notifier for the given device.
>> + * cec_notifier_get_conn - find or create a new cec_notifier for the given
>> + * device and connector tuple.
>> * @dev: device that sends the events.
>> + * @conn: the connector name from which the event occurs
>
> Probably best to use "name" instead of connector, since it doesn't necessarily
> _have_ to be a connector name. So, cec_notifier_get_by_name(dev, name)

I don't have a stong opinion, but since the CEC is tied to a connector, it should
mention connector, maybe conn_name ?

>
>> *
>> * If a notifier for device @dev already exists, then increase the refcount
>> * and return that notifier.
>> @@ -31,7 +33,8 @@ struct cec_notifier;
>> *
>> * Return NULL if the memory could not be allocated.
>> */
>> -struct cec_notifier *cec_notifier_get(struct device *dev);
>> +struct cec_notifier *cec_notifier_get_conn(struct device *dev,
>> + const char *conn);
>>
>> /**
>> * cec_notifier_put - decrease refcount and delete when the refcount reaches 0.
>> @@ -85,7 +88,8 @@ void cec_register_cec_notifier(struct cec_adapter *adap,
>> struct cec_notifier *notifier);
>>
>> #else
>> -static inline struct cec_notifier *cec_notifier_get(struct device *dev)
>> +static inline struct cec_notifier *cec_notifier_get_conn(struct device *dev,
>> + const char *conn)
>> {
>> /* A non-NULL pointer is expected on success */
>> return (struct cec_notifier *)0xdeadfeed;
>> @@ -121,6 +125,23 @@ static inline void cec_register_cec_notifier(struct cec_adapter *adap,
>> #endif
>>
>> /**
>> + * cec_notifier_get - find or create a new cec_notifier for the given device.
>> + * @dev: device that sends the events.
>> + *
>> + * If a notifier for device @dev already exists, then increase the refcount
>> + * and return that notifier.
>> + *
>> + * If it doesn't exist, then allocate a new notifier struct and return a
>> + * pointer to that new struct.
>
> You might also want to cover the case where you have multiple named notifiers
> for the same device. It looks like it just grabs the first one?

Yes, the code grabs the first one if not precised, do you mean I'll need to add
a line to document the behaviour ?

>
> Sean
>
>> + *
>> + * Return NULL if the memory could not be allocated.
>> + */
>> +static inline struct cec_notifier *cec_notifier_get(struct device *dev)
>> +{
>> + return cec_notifier_get_conn(dev, NULL);
>> +}
>> +
>> +/**
>> * cec_notifier_phys_addr_invalidate() - set the physical address to INVALID
>> *
>> * @n: the CEC notifier
>> --
>> 2.7.4
>>
>

Thanks,
Neil

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