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* [PATCHv4 0/5] cec-gpio: add HDMI CEC GPIO-based driver
@ 2017-08-31 11:01 ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: devicetree, dri-devel

From: Hans Verkuil <hans.verkuil@cisco.com>

This driver adds support for CEC implementations that use a pull-up
GPIO line. While SoCs exist that do this, the primary use-case is to
turn a single-board computer into a cheap CEC debugger.

Together with 'cec-ctl --monitor-pin' you can do low-level CEC bus
monitoring and do protocol analysis. And error injection is also
planned for the future.

Here is an example using the Raspberry Pi 3:

https://hverkuil.home.xs4all.nl/rpi3-cec.jpg

While this example is for the Rpi, this driver will work for any
SoC with a pull-up GPIO line.

In addition the cec-gpio driver can optionally monitor the HPD line.
The state of the HPD line influences the CEC behavior so it is very
useful to be able to monitor both.

And some HDMI sinks are known to quickly toggle the HPD when e.g.
switching between inputs. So it is useful to be able to see an event
when the HPD changes value.

The first two patches add support for the new HPD events. The last
three patches are for the cec-gpio driver itself.

Regards,

        Hans

Changes since v3:

- cec-gpio.txt: refer to lines instead of pins and use OPEN_DRAIN
  in the example.
- Kconfig: add select GPIOLIB
- cec-gpio.c: switch to gpiod.
- cec-core.c: initialize the devnode mutex/list in allocate_adapter.
  Doing this in register_adapter is too late if the HPD is high.

Changes since v2:

- Add support for HPD events.
- Switch from pin BCM4 to pin BCM7 in the bindings example

Changes since v1:

- Updated the bindings doc to not refer to the driver, instead
  refer to the hardware.


Hans Verkuil (5):
  cec: add CEC_EVENT_PIN_HPD_LOW/HIGH events
  cec-ioc-dqevent.rst: document new CEC_EVENT_PIN_HPD_LOW/HIGH events
  dt-bindings: document the CEC GPIO bindings
  cec-gpio: add HDMI CEC GPIO driver
  MAINTAINERS: add cec-gpio entry

 .../devicetree/bindings/media/cec-gpio.txt         |  22 ++
 Documentation/media/uapi/cec/cec-ioc-dqevent.rst   |  18 ++
 MAINTAINERS                                        |   9 +
 drivers/media/cec/cec-adap.c                       |  18 +-
 drivers/media/cec/cec-api.c                        |  18 +-
 drivers/media/cec/cec-core.c                       |   8 +-
 drivers/media/platform/Kconfig                     |  10 +
 drivers/media/platform/Makefile                    |   2 +
 drivers/media/platform/cec-gpio/Makefile           |   1 +
 drivers/media/platform/cec-gpio/cec-gpio.c         | 236 +++++++++++++++++++++
 include/media/cec-pin.h                            |   4 +
 include/media/cec.h                                |  12 +-
 include/uapi/linux/cec.h                           |   2 +
 13 files changed, 350 insertions(+), 10 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
 create mode 100644 drivers/media/platform/cec-gpio/Makefile
 create mode 100644 drivers/media/platform/cec-gpio/cec-gpio.c

-- 
2.14.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 27+ messages in thread
* [PATCHv4 0/5] cec-gpio: add HDMI CEC GPIO-based driver
@ 2017-08-31 11:01 ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: dri-devel, devicetree, Linus Walleij

From: Hans Verkuil <hans.verkuil@cisco.com>

This driver adds support for CEC implementations that use a pull-up
GPIO line. While SoCs exist that do this, the primary use-case is to
turn a single-board computer into a cheap CEC debugger.

Together with 'cec-ctl --monitor-pin' you can do low-level CEC bus
monitoring and do protocol analysis. And error injection is also
planned for the future.

Here is an example using the Raspberry Pi 3:

https://hverkuil.home.xs4all.nl/rpi3-cec.jpg

While this example is for the Rpi, this driver will work for any
SoC with a pull-up GPIO line.

In addition the cec-gpio driver can optionally monitor the HPD line.
The state of the HPD line influences the CEC behavior so it is very
useful to be able to monitor both.

And some HDMI sinks are known to quickly toggle the HPD when e.g.
switching between inputs. So it is useful to be able to see an event
when the HPD changes value.

The first two patches add support for the new HPD events. The last
three patches are for the cec-gpio driver itself.

Regards,

        Hans

Changes since v3:

- cec-gpio.txt: refer to lines instead of pins and use OPEN_DRAIN
  in the example.
- Kconfig: add select GPIOLIB
- cec-gpio.c: switch to gpiod.
- cec-core.c: initialize the devnode mutex/list in allocate_adapter.
  Doing this in register_adapter is too late if the HPD is high.

Changes since v2:

- Add support for HPD events.
- Switch from pin BCM4 to pin BCM7 in the bindings example

Changes since v1:

- Updated the bindings doc to not refer to the driver, instead
  refer to the hardware.


Hans Verkuil (5):
  cec: add CEC_EVENT_PIN_HPD_LOW/HIGH events
  cec-ioc-dqevent.rst: document new CEC_EVENT_PIN_HPD_LOW/HIGH events
  dt-bindings: document the CEC GPIO bindings
  cec-gpio: add HDMI CEC GPIO driver
  MAINTAINERS: add cec-gpio entry

 .../devicetree/bindings/media/cec-gpio.txt         |  22 ++
 Documentation/media/uapi/cec/cec-ioc-dqevent.rst   |  18 ++
 MAINTAINERS                                        |   9 +
 drivers/media/cec/cec-adap.c                       |  18 +-
 drivers/media/cec/cec-api.c                        |  18 +-
 drivers/media/cec/cec-core.c                       |   8 +-
 drivers/media/platform/Kconfig                     |  10 +
 drivers/media/platform/Makefile                    |   2 +
 drivers/media/platform/cec-gpio/Makefile           |   1 +
 drivers/media/platform/cec-gpio/cec-gpio.c         | 236 +++++++++++++++++++++
 include/media/cec-pin.h                            |   4 +
 include/media/cec.h                                |  12 +-
 include/uapi/linux/cec.h                           |   2 +
 13 files changed, 350 insertions(+), 10 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
 create mode 100644 drivers/media/platform/cec-gpio/Makefile
 create mode 100644 drivers/media/platform/cec-gpio/cec-gpio.c

-- 
2.14.1

^ permalink raw reply	[flat|nested] 27+ messages in thread
* [PATCHv4 1/5] cec: add CEC_EVENT_PIN_HPD_LOW/HIGH events
  2017-08-31 11:01 ` Hans Verkuil
  (?)
@ 2017-08-31 11:01 ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: dri-devel, devicetree, Linus Walleij, Hans Verkuil

From: Hans Verkuil <hans.verkuil@cisco.com>

Add support for two new low-level events: PIN_HPD_LOW and PIN_HPD_HIGH.

This is specifically meant for use with the upcoming cec-gpio driver
and makes it possible to trace when the HPD pin changes. Some HDMI
sinks do strange things with the HPD and this makes it easy to debug
this.

Note that this also moves the initialization of a devnode mutex and
list to the allocate_adapter function: if the HPD is high, then as
soon as the HPD interrupt is created an interrupt occurs and
cec_queue_pin_hpd_event() is called which requires that the devnode
mutex and list are initialized.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/cec/cec-adap.c | 18 +++++++++++++++++-
 drivers/media/cec/cec-api.c  | 18 ++++++++++++++----
 drivers/media/cec/cec-core.c |  8 ++++----
 include/media/cec-pin.h      |  4 ++++
 include/media/cec.h          | 12 +++++++++++-
 include/uapi/linux/cec.h     |  2 ++
 6 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index dd769e40416f..eb904a71609a 100644
--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -86,7 +86,7 @@ void cec_queue_event_fh(struct cec_fh *fh,
 			const struct cec_event *new_ev, u64 ts)
 {
 	static const u8 max_events[CEC_NUM_EVENTS] = {
-		1, 1, 64, 64,
+		1, 1, 64, 64, 8, 8,
 	};
 	struct cec_event_entry *entry;
 	unsigned int ev_idx = new_ev->event - 1;
@@ -170,6 +170,22 @@ void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high, ktime_t ts)
 }
 EXPORT_SYMBOL_GPL(cec_queue_pin_cec_event);
 
+/* Notify userspace that the HPD pin changed state at the given time. */
+void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts)
+{
+	struct cec_event ev = {
+		.event = is_high ? CEC_EVENT_PIN_HPD_HIGH :
+				   CEC_EVENT_PIN_HPD_LOW,
+	};
+	struct cec_fh *fh;
+
+	mutex_lock(&adap->devnode.lock);
+	list_for_each_entry(fh, &adap->devnode.fhs, list)
+		cec_queue_event_fh(fh, &ev, ktime_to_ns(ts));
+	mutex_unlock(&adap->devnode.lock);
+}
+EXPORT_SYMBOL_GPL(cec_queue_pin_hpd_event);
+
 /*
  * Queue a new message for this filehandle.
  *
diff --git a/drivers/media/cec/cec-api.c b/drivers/media/cec/cec-api.c
index a079f7fe018c..465bb3ec21f6 100644
--- a/drivers/media/cec/cec-api.c
+++ b/drivers/media/cec/cec-api.c
@@ -529,7 +529,7 @@ static int cec_open(struct inode *inode, struct file *filp)
 	 * Initial events that are automatically sent when the cec device is
 	 * opened.
 	 */
-	struct cec_event ev_state = {
+	struct cec_event ev = {
 		.event = CEC_EVENT_STATE_CHANGE,
 		.flags = CEC_EVENT_FL_INITIAL_STATE,
 	};
@@ -569,9 +569,19 @@ static int cec_open(struct inode *inode, struct file *filp)
 	filp->private_data = fh;
 
 	/* Queue up initial state events */
-	ev_state.state_change.phys_addr = adap->phys_addr;
-	ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
-	cec_queue_event_fh(fh, &ev_state, 0);
+	ev.state_change.phys_addr = adap->phys_addr;
+	ev.state_change.log_addr_mask = adap->log_addrs.log_addr_mask;
+	cec_queue_event_fh(fh, &ev, 0);
+#ifdef CONFIG_CEC_PIN
+	if (adap->pin && adap->pin->ops->read_hpd) {
+		err = adap->pin->ops->read_hpd(adap);
+		if (err >= 0) {
+			ev.event = err ? CEC_EVENT_PIN_HPD_HIGH :
+					 CEC_EVENT_PIN_HPD_LOW;
+			cec_queue_event_fh(fh, &ev, 0);
+		}
+	}
+#endif
 
 	list_add(&fh->list, &devnode->fhs);
 	mutex_unlock(&devnode->lock);
diff --git a/drivers/media/cec/cec-core.c b/drivers/media/cec/cec-core.c
index 648136e552d5..e3a1fb6d6690 100644
--- a/drivers/media/cec/cec-core.c
+++ b/drivers/media/cec/cec-core.c
@@ -112,10 +112,6 @@ static int __must_check cec_devnode_register(struct cec_devnode *devnode,
 	int minor;
 	int ret;
 
-	/* Initialization */
-	INIT_LIST_HEAD(&devnode->fhs);
-	mutex_init(&devnode->lock);
-
 	/* Part 1: Find a free minor number */
 	mutex_lock(&cec_devnode_lock);
 	minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
@@ -242,6 +238,10 @@ struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
 	INIT_LIST_HEAD(&adap->wait_queue);
 	init_waitqueue_head(&adap->kthread_waitq);
 
+	/* adap->devnode initialization */
+	INIT_LIST_HEAD(&adap->devnode.fhs);
+	mutex_init(&adap->devnode.lock);
+
 	adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
 	if (IS_ERR(adap->kthread)) {
 		pr_err("cec-%s: kernel_thread() failed\n", name);
diff --git a/include/media/cec-pin.h b/include/media/cec-pin.h
index f09cc9579d53..ea84b9c9e0c3 100644
--- a/include/media/cec-pin.h
+++ b/include/media/cec-pin.h
@@ -97,6 +97,9 @@ enum cec_pin_state {
  * @free:	optional. Free any allocated resources. Called when the
  *		adapter is deleted.
  * @status:	optional, log status information.
+ * @read_hpd:	read the HPD pin. Return true if high, false if low or
+ *		an error if negative. If NULL or -ENOTTY is returned,
+ *		then this is not supported.
  *
  * These operations are used by the cec pin framework to manipulate
  * the CEC pin.
@@ -109,6 +112,7 @@ struct cec_pin_ops {
 	void (*disable_irq)(struct cec_adapter *adap);
 	void (*free)(struct cec_adapter *adap);
 	void (*status)(struct cec_adapter *adap, struct seq_file *file);
+	int  (*read_hpd)(struct cec_adapter *adap);
 };
 
 #define CEC_NUM_PIN_EVENTS 128
diff --git a/include/media/cec.h b/include/media/cec.h
index df6b3bd31284..9d0f983faea9 100644
--- a/include/media/cec.h
+++ b/include/media/cec.h
@@ -91,7 +91,7 @@ struct cec_event_entry {
 };
 
 #define CEC_NUM_CORE_EVENTS 2
-#define CEC_NUM_EVENTS CEC_EVENT_PIN_CEC_HIGH
+#define CEC_NUM_EVENTS CEC_EVENT_PIN_HPD_HIGH
 
 struct cec_fh {
 	struct list_head	list;
@@ -296,6 +296,16 @@ static inline void cec_received_msg(struct cec_adapter *adap,
 void cec_queue_pin_cec_event(struct cec_adapter *adap,
 			     bool is_high, ktime_t ts);
 
+/**
+ * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp.
+ *
+ * @adap:	pointer to the cec adapter
+ * @is_high:	when true the HPD pin is high, otherwise it is low
+ * @ts:		the timestamp for this event
+ *
+ */
+void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
+
 /**
  * cec_get_edid_phys_addr() - find and return the physical address
  *
diff --git a/include/uapi/linux/cec.h b/include/uapi/linux/cec.h
index 4351c3481aea..b9f8df3a0477 100644
--- a/include/uapi/linux/cec.h
+++ b/include/uapi/linux/cec.h
@@ -410,6 +410,8 @@ struct cec_log_addrs {
 #define CEC_EVENT_LOST_MSGS		2
 #define CEC_EVENT_PIN_CEC_LOW		3
 #define CEC_EVENT_PIN_CEC_HIGH		4
+#define CEC_EVENT_PIN_HPD_LOW		5
+#define CEC_EVENT_PIN_HPD_HIGH		6
 
 #define CEC_EVENT_FL_INITIAL_STATE	(1 << 0)
 #define CEC_EVENT_FL_DROPPED_EVENTS	(1 << 1)
-- 
2.14.1

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 2/5] cec-ioc-dqevent.rst: document new CEC_EVENT_PIN_HPD_LOW/HIGH events
  2017-08-31 11:01 ` Hans Verkuil
@ 2017-08-31 11:01     ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media-u79uwXL29TY76Z2rM5mHXA
  Cc: dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Linus Walleij, Hans Verkuil

From: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>

Document these new CEC events.

Signed-off-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
---
 Documentation/media/uapi/cec/cec-ioc-dqevent.rst | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Documentation/media/uapi/cec/cec-ioc-dqevent.rst b/Documentation/media/uapi/cec/cec-ioc-dqevent.rst
index db615e3405c0..32b47763f5a6 100644
--- a/Documentation/media/uapi/cec/cec-ioc-dqevent.rst
+++ b/Documentation/media/uapi/cec/cec-ioc-dqevent.rst
@@ -160,6 +160,24 @@ it is guaranteed that the state did change in between the two events.
       - Generated if the CEC pin goes from a low voltage to a high voltage.
         Only applies to adapters that have the ``CEC_CAP_MONITOR_PIN``
 	capability set.
+    * .. _`CEC-EVENT-PIN-HPD-LOW`:
+
+      - ``CEC_EVENT_PIN_HPD_LOW``
+      - 5
+      - Generated if the HPD pin goes from a high voltage to a low voltage.
+        Only applies to adapters that have the ``CEC_CAP_MONITOR_PIN``
+	capability set. When open() is called, the HPD pin can be read and
+	the HPD is low, then an initial event will be generated for that
+	filehandle.
+    * .. _`CEC-EVENT-PIN-HPD-HIGH`:
+
+      - ``CEC_EVENT_PIN_HPD_HIGH``
+      - 6
+      - Generated if the HPD pin goes from a low voltage to a high voltage.
+        Only applies to adapters that have the ``CEC_CAP_MONITOR_PIN``
+	capability set. When open() is called, the HPD pin can be read and
+	the HPD is high, then an initial event will be generated for that
+	filehandle.
 
 
 .. tabularcolumns:: |p{6.0cm}|p{0.6cm}|p{10.9cm}|
-- 
2.14.1

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^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 2/5] cec-ioc-dqevent.rst: document new CEC_EVENT_PIN_HPD_LOW/HIGH events
@ 2017-08-31 11:01     ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: dri-devel, devicetree, Linus Walleij, Hans Verkuil

From: Hans Verkuil <hans.verkuil@cisco.com>

Document these new CEC events.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 Documentation/media/uapi/cec/cec-ioc-dqevent.rst | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Documentation/media/uapi/cec/cec-ioc-dqevent.rst b/Documentation/media/uapi/cec/cec-ioc-dqevent.rst
index db615e3405c0..32b47763f5a6 100644
--- a/Documentation/media/uapi/cec/cec-ioc-dqevent.rst
+++ b/Documentation/media/uapi/cec/cec-ioc-dqevent.rst
@@ -160,6 +160,24 @@ it is guaranteed that the state did change in between the two events.
       - Generated if the CEC pin goes from a low voltage to a high voltage.
         Only applies to adapters that have the ``CEC_CAP_MONITOR_PIN``
 	capability set.
+    * .. _`CEC-EVENT-PIN-HPD-LOW`:
+
+      - ``CEC_EVENT_PIN_HPD_LOW``
+      - 5
+      - Generated if the HPD pin goes from a high voltage to a low voltage.
+        Only applies to adapters that have the ``CEC_CAP_MONITOR_PIN``
+	capability set. When open() is called, the HPD pin can be read and
+	the HPD is low, then an initial event will be generated for that
+	filehandle.
+    * .. _`CEC-EVENT-PIN-HPD-HIGH`:
+
+      - ``CEC_EVENT_PIN_HPD_HIGH``
+      - 6
+      - Generated if the HPD pin goes from a low voltage to a high voltage.
+        Only applies to adapters that have the ``CEC_CAP_MONITOR_PIN``
+	capability set. When open() is called, the HPD pin can be read and
+	the HPD is high, then an initial event will be generated for that
+	filehandle.
 
 
 .. tabularcolumns:: |p{6.0cm}|p{0.6cm}|p{10.9cm}|
-- 
2.14.1

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-08-31 11:01 ` Hans Verkuil
@ 2017-08-31 11:01     ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media-u79uwXL29TY76Z2rM5mHXA
  Cc: dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Linus Walleij, Hans Verkuil

From: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>

Document the bindings for the cec-gpio module for hardware where the
CEC line and optionally the HPD line are connected to GPIO lines.

Signed-off-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
---
 .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt

diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
new file mode 100644
index 000000000000..db20a7452dbd
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
@@ -0,0 +1,22 @@
+* HDMI CEC GPIO driver
+
+The HDMI CEC GPIO module supports CEC implementations where the CEC line
+is hooked up to a pull-up GPIO line and - optionally - the HPD line is
+hooked up to another GPIO line.
+
+Required properties:
+  - compatible: value must be "cec-gpio"
+  - cec-gpio: gpio that the CEC line is connected to
+
+Optional property:
+  - hpd-gpio: gpio that the HPD line is connected to
+
+Example for the Raspberry Pi 3 where the CEC line is connected to
+pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
+connected to pin 11 aka BCM17:
+
+cec-gpio@7 {
+       compatible = "cec-gpio";
+       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
+       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
+};
-- 
2.14.1

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^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
@ 2017-08-31 11:01     ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: dri-devel, devicetree, Linus Walleij, Hans Verkuil

From: Hans Verkuil <hans.verkuil@cisco.com>

Document the bindings for the cec-gpio module for hardware where the
CEC line and optionally the HPD line are connected to GPIO lines.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt

diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
new file mode 100644
index 000000000000..db20a7452dbd
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
@@ -0,0 +1,22 @@
+* HDMI CEC GPIO driver
+
+The HDMI CEC GPIO module supports CEC implementations where the CEC line
+is hooked up to a pull-up GPIO line and - optionally - the HPD line is
+hooked up to another GPIO line.
+
+Required properties:
+  - compatible: value must be "cec-gpio"
+  - cec-gpio: gpio that the CEC line is connected to
+
+Optional property:
+  - hpd-gpio: gpio that the HPD line is connected to
+
+Example for the Raspberry Pi 3 where the CEC line is connected to
+pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
+connected to pin 11 aka BCM17:
+
+cec-gpio@7 {
+       compatible = "cec-gpio";
+       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
+       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
+};
-- 
2.14.1

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 4/5] cec-gpio: add HDMI CEC GPIO driver
  2017-08-31 11:01 ` Hans Verkuil
@ 2017-08-31 11:01   ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: devicetree, Hans Verkuil, dri-devel

From: Hans Verkuil <hans.verkuil@cisco.com>

Add a simple HDMI CEC GPIO driver that sits on top of the cec-pin framework.

While I have heard of SoCs that use the GPIO pin for CEC (apparently an
early RockChip SoC used that), the main use-case of this driver is to
function as a debugging tool.

By connecting the CEC line to a GPIO pin on a Raspberry Pi 3 for example
it turns it into a CEC debugger and protocol analyzer.

With 'cec-ctl --monitor-pin' the CEC traffic can be analyzed.

But of course it can also be used with any hardware project where the
HDMI CEC line is hooked up to a pull-up gpio line.

In addition this has (optional) support for tracing HPD changes if the
HPD is connected to a GPIO.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/Kconfig             |  10 ++
 drivers/media/platform/Makefile            |   2 +
 drivers/media/platform/cec-gpio/Makefile   |   1 +
 drivers/media/platform/cec-gpio/cec-gpio.c | 236 +++++++++++++++++++++++++++++
 4 files changed, 249 insertions(+)
 create mode 100644 drivers/media/platform/cec-gpio/Makefile
 create mode 100644 drivers/media/platform/cec-gpio/cec-gpio.c

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index 7e7cc49b8674..e4c89a16a3e7 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -553,6 +553,16 @@ config VIDEO_MESON_AO_CEC
 	  This is a driver for Amlogic Meson SoCs AO CEC interface. It uses the
 	  generic CEC framework interface.
 	  CEC bus is present in the HDMI connector and enables communication
+
+config CEC_GPIO
+	tristate "Generic GPIO-based CEC driver"
+	depends on PREEMPT
+	select CEC_CORE
+	select CEC_PIN
+	select GPIOLIB
+	---help---
+	  This is a generic GPIO-based CEC driver.
+	  The CEC bus is present in the HDMI connector and enables communication
 	  between compatible devices.
 
 config VIDEO_SAMSUNG_S5P_CEC
diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
index c1ef946bf032..9bf48f118537 100644
--- a/drivers/media/platform/Makefile
+++ b/drivers/media/platform/Makefile
@@ -26,6 +26,8 @@ obj-$(CONFIG_VIDEO_CODA) 		+= coda/
 
 obj-$(CONFIG_VIDEO_SH_VEU)		+= sh_veu.o
 
+obj-$(CONFIG_CEC_GPIO)			+= cec-gpio/
+
 obj-$(CONFIG_VIDEO_MEM2MEM_DEINTERLACE)	+= m2m-deinterlace.o
 
 obj-$(CONFIG_VIDEO_MUX)			+= video-mux.o
diff --git a/drivers/media/platform/cec-gpio/Makefile b/drivers/media/platform/cec-gpio/Makefile
new file mode 100644
index 000000000000..e82b258afa55
--- /dev/null
+++ b/drivers/media/platform/cec-gpio/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_CEC_GPIO) += cec-gpio.o
diff --git a/drivers/media/platform/cec-gpio/cec-gpio.c b/drivers/media/platform/cec-gpio/cec-gpio.c
new file mode 100644
index 000000000000..eb982bce99fc
--- /dev/null
+++ b/drivers/media/platform/cec-gpio/cec-gpio.c
@@ -0,0 +1,236 @@
+/*
+ * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/consumer.h>
+#include <media/cec-pin.h>
+
+struct cec_gpio {
+	struct cec_adapter	*adap;
+	struct device		*dev;
+
+	struct gpio_desc	*cec_gpio;
+	int			cec_irq;
+	bool			cec_is_low;
+	bool			cec_have_irq;
+
+	struct gpio_desc	*hpd_gpio;
+	int			hpd_irq;
+	bool			hpd_is_high;
+	ktime_t			hpd_ts;
+};
+
+static bool cec_gpio_read(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_is_low)
+		return false;
+	return gpiod_get_value(cec->cec_gpio);
+}
+
+static void cec_gpio_high(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (!cec->cec_is_low)
+		return;
+	cec->cec_is_low = false;
+	gpiod_set_value(cec->cec_gpio, 1);
+}
+
+static void cec_gpio_low(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_is_low)
+		return;
+	if (WARN_ON_ONCE(cec->cec_have_irq))
+		free_irq(cec->cec_irq, cec);
+	cec->cec_have_irq = false;
+	cec->cec_is_low = true;
+	gpiod_set_value(cec->cec_gpio, 0);
+}
+
+static irqreturn_t cec_hpd_gpio_irq_handler_thread(int irq, void *priv)
+{
+	struct cec_gpio *cec = priv;
+
+	cec_queue_pin_hpd_event(cec->adap, cec->hpd_is_high, cec->hpd_ts);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t cec_hpd_gpio_irq_handler(int irq, void *priv)
+{
+	struct cec_gpio *cec = priv;
+
+	cec->hpd_ts = ktime_get();
+	cec->hpd_is_high = gpiod_get_value(cec->hpd_gpio);
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t cec_gpio_irq_handler(int irq, void *priv)
+{
+	struct cec_gpio *cec = priv;
+
+	cec_pin_changed(cec->adap, gpiod_get_value(cec->cec_gpio));
+	return IRQ_HANDLED;
+}
+
+static bool cec_gpio_enable_irq(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_have_irq)
+		return true;
+
+	if (request_irq(cec->cec_irq, cec_gpio_irq_handler,
+			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+			adap->name, cec))
+		return false;
+	cec->cec_have_irq = true;
+	return true;
+}
+
+static void cec_gpio_disable_irq(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_have_irq)
+		free_irq(cec->cec_irq, cec);
+	cec->cec_have_irq = false;
+}
+
+static void cec_gpio_status(struct cec_adapter *adap, struct seq_file *file)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	seq_printf(file, "mode: %s\n", cec->cec_is_low ? "low-drive" : "read");
+	if (cec->cec_have_irq)
+		seq_printf(file, "using irq: %d\n", cec->cec_irq);
+	if (cec->hpd_gpio)
+		seq_printf(file, "hpd: %s\n",
+			   cec->hpd_is_high ? "high" : "low");
+}
+
+static int cec_gpio_read_hpd(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (!cec->hpd_gpio)
+		return -ENOTTY;
+	return gpiod_get_value(cec->hpd_gpio);
+}
+
+static void cec_gpio_free(struct cec_adapter *adap)
+{
+	cec_gpio_disable_irq(adap);
+}
+
+static const struct cec_pin_ops cec_gpio_pin_ops = {
+	.read = cec_gpio_read,
+	.low = cec_gpio_low,
+	.high = cec_gpio_high,
+	.enable_irq = cec_gpio_enable_irq,
+	.disable_irq = cec_gpio_disable_irq,
+	.status = cec_gpio_status,
+	.free = cec_gpio_free,
+	.read_hpd = cec_gpio_read_hpd,
+};
+
+static int cec_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cec_gpio *cec;
+	int ret;
+
+	cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL);
+	if (!cec)
+		return -ENOMEM;
+
+	cec->dev = dev;
+
+	cec->cec_gpio = devm_gpiod_get(dev, "cec", GPIOD_IN);
+	if (IS_ERR(cec->cec_gpio))
+		return PTR_ERR(cec->cec_gpio);
+	cec->cec_irq = gpiod_to_irq(cec->cec_gpio);
+
+	cec->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
+	if (IS_ERR(cec->hpd_gpio))
+		return PTR_ERR(cec->hpd_gpio);
+
+	cec->adap = cec_pin_allocate_adapter(&cec_gpio_pin_ops,
+		cec, pdev->name, CEC_CAP_DEFAULTS | CEC_CAP_PHYS_ADDR |
+				 CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN);
+	if (IS_ERR(cec->adap))
+		return PTR_ERR(cec->adap);
+
+	if (cec->hpd_gpio) {
+		cec->hpd_irq = gpiod_to_irq(cec->hpd_gpio);
+		ret = devm_request_threaded_irq(dev, cec->hpd_irq,
+			cec_hpd_gpio_irq_handler,
+			cec_hpd_gpio_irq_handler_thread,
+			IRQF_ONESHOT |
+			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+			"hpd-gpio", cec);
+		if (ret)
+			return ret;
+	}
+
+	ret = cec_register_adapter(cec->adap, &pdev->dev);
+	if (ret) {
+		cec_delete_adapter(cec->adap);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, cec);
+	return 0;
+}
+
+static int cec_gpio_remove(struct platform_device *pdev)
+{
+	struct cec_gpio *cec = platform_get_drvdata(pdev);
+
+	cec_unregister_adapter(cec->adap);
+	return 0;
+}
+
+static const struct of_device_id cec_gpio_match[] = {
+	{
+		.compatible	= "cec-gpio",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, cec_gpio_match);
+
+static struct platform_driver cec_gpio_pdrv = {
+	.probe	= cec_gpio_probe,
+	.remove = cec_gpio_remove,
+	.driver = {
+		.name		= "cec-gpio",
+		.of_match_table	= cec_gpio_match,
+	},
+};
+
+module_platform_driver(cec_gpio_pdrv);
+
+MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("CEC GPIO driver");
-- 
2.14.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 4/5] cec-gpio: add HDMI CEC GPIO driver
@ 2017-08-31 11:01   ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: dri-devel, devicetree, Linus Walleij, Hans Verkuil

From: Hans Verkuil <hans.verkuil@cisco.com>

Add a simple HDMI CEC GPIO driver that sits on top of the cec-pin framework.

While I have heard of SoCs that use the GPIO pin for CEC (apparently an
early RockChip SoC used that), the main use-case of this driver is to
function as a debugging tool.

By connecting the CEC line to a GPIO pin on a Raspberry Pi 3 for example
it turns it into a CEC debugger and protocol analyzer.

With 'cec-ctl --monitor-pin' the CEC traffic can be analyzed.

But of course it can also be used with any hardware project where the
HDMI CEC line is hooked up to a pull-up gpio line.

In addition this has (optional) support for tracing HPD changes if the
HPD is connected to a GPIO.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/Kconfig             |  10 ++
 drivers/media/platform/Makefile            |   2 +
 drivers/media/platform/cec-gpio/Makefile   |   1 +
 drivers/media/platform/cec-gpio/cec-gpio.c | 236 +++++++++++++++++++++++++++++
 4 files changed, 249 insertions(+)
 create mode 100644 drivers/media/platform/cec-gpio/Makefile
 create mode 100644 drivers/media/platform/cec-gpio/cec-gpio.c

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index 7e7cc49b8674..e4c89a16a3e7 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -553,6 +553,16 @@ config VIDEO_MESON_AO_CEC
 	  This is a driver for Amlogic Meson SoCs AO CEC interface. It uses the
 	  generic CEC framework interface.
 	  CEC bus is present in the HDMI connector and enables communication
+
+config CEC_GPIO
+	tristate "Generic GPIO-based CEC driver"
+	depends on PREEMPT
+	select CEC_CORE
+	select CEC_PIN
+	select GPIOLIB
+	---help---
+	  This is a generic GPIO-based CEC driver.
+	  The CEC bus is present in the HDMI connector and enables communication
 	  between compatible devices.
 
 config VIDEO_SAMSUNG_S5P_CEC
diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
index c1ef946bf032..9bf48f118537 100644
--- a/drivers/media/platform/Makefile
+++ b/drivers/media/platform/Makefile
@@ -26,6 +26,8 @@ obj-$(CONFIG_VIDEO_CODA) 		+= coda/
 
 obj-$(CONFIG_VIDEO_SH_VEU)		+= sh_veu.o
 
+obj-$(CONFIG_CEC_GPIO)			+= cec-gpio/
+
 obj-$(CONFIG_VIDEO_MEM2MEM_DEINTERLACE)	+= m2m-deinterlace.o
 
 obj-$(CONFIG_VIDEO_MUX)			+= video-mux.o
diff --git a/drivers/media/platform/cec-gpio/Makefile b/drivers/media/platform/cec-gpio/Makefile
new file mode 100644
index 000000000000..e82b258afa55
--- /dev/null
+++ b/drivers/media/platform/cec-gpio/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_CEC_GPIO) += cec-gpio.o
diff --git a/drivers/media/platform/cec-gpio/cec-gpio.c b/drivers/media/platform/cec-gpio/cec-gpio.c
new file mode 100644
index 000000000000..eb982bce99fc
--- /dev/null
+++ b/drivers/media/platform/cec-gpio/cec-gpio.c
@@ -0,0 +1,236 @@
+/*
+ * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/consumer.h>
+#include <media/cec-pin.h>
+
+struct cec_gpio {
+	struct cec_adapter	*adap;
+	struct device		*dev;
+
+	struct gpio_desc	*cec_gpio;
+	int			cec_irq;
+	bool			cec_is_low;
+	bool			cec_have_irq;
+
+	struct gpio_desc	*hpd_gpio;
+	int			hpd_irq;
+	bool			hpd_is_high;
+	ktime_t			hpd_ts;
+};
+
+static bool cec_gpio_read(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_is_low)
+		return false;
+	return gpiod_get_value(cec->cec_gpio);
+}
+
+static void cec_gpio_high(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (!cec->cec_is_low)
+		return;
+	cec->cec_is_low = false;
+	gpiod_set_value(cec->cec_gpio, 1);
+}
+
+static void cec_gpio_low(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_is_low)
+		return;
+	if (WARN_ON_ONCE(cec->cec_have_irq))
+		free_irq(cec->cec_irq, cec);
+	cec->cec_have_irq = false;
+	cec->cec_is_low = true;
+	gpiod_set_value(cec->cec_gpio, 0);
+}
+
+static irqreturn_t cec_hpd_gpio_irq_handler_thread(int irq, void *priv)
+{
+	struct cec_gpio *cec = priv;
+
+	cec_queue_pin_hpd_event(cec->adap, cec->hpd_is_high, cec->hpd_ts);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t cec_hpd_gpio_irq_handler(int irq, void *priv)
+{
+	struct cec_gpio *cec = priv;
+
+	cec->hpd_ts = ktime_get();
+	cec->hpd_is_high = gpiod_get_value(cec->hpd_gpio);
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t cec_gpio_irq_handler(int irq, void *priv)
+{
+	struct cec_gpio *cec = priv;
+
+	cec_pin_changed(cec->adap, gpiod_get_value(cec->cec_gpio));
+	return IRQ_HANDLED;
+}
+
+static bool cec_gpio_enable_irq(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_have_irq)
+		return true;
+
+	if (request_irq(cec->cec_irq, cec_gpio_irq_handler,
+			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+			adap->name, cec))
+		return false;
+	cec->cec_have_irq = true;
+	return true;
+}
+
+static void cec_gpio_disable_irq(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (cec->cec_have_irq)
+		free_irq(cec->cec_irq, cec);
+	cec->cec_have_irq = false;
+}
+
+static void cec_gpio_status(struct cec_adapter *adap, struct seq_file *file)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	seq_printf(file, "mode: %s\n", cec->cec_is_low ? "low-drive" : "read");
+	if (cec->cec_have_irq)
+		seq_printf(file, "using irq: %d\n", cec->cec_irq);
+	if (cec->hpd_gpio)
+		seq_printf(file, "hpd: %s\n",
+			   cec->hpd_is_high ? "high" : "low");
+}
+
+static int cec_gpio_read_hpd(struct cec_adapter *adap)
+{
+	struct cec_gpio *cec = cec_get_drvdata(adap);
+
+	if (!cec->hpd_gpio)
+		return -ENOTTY;
+	return gpiod_get_value(cec->hpd_gpio);
+}
+
+static void cec_gpio_free(struct cec_adapter *adap)
+{
+	cec_gpio_disable_irq(adap);
+}
+
+static const struct cec_pin_ops cec_gpio_pin_ops = {
+	.read = cec_gpio_read,
+	.low = cec_gpio_low,
+	.high = cec_gpio_high,
+	.enable_irq = cec_gpio_enable_irq,
+	.disable_irq = cec_gpio_disable_irq,
+	.status = cec_gpio_status,
+	.free = cec_gpio_free,
+	.read_hpd = cec_gpio_read_hpd,
+};
+
+static int cec_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cec_gpio *cec;
+	int ret;
+
+	cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL);
+	if (!cec)
+		return -ENOMEM;
+
+	cec->dev = dev;
+
+	cec->cec_gpio = devm_gpiod_get(dev, "cec", GPIOD_IN);
+	if (IS_ERR(cec->cec_gpio))
+		return PTR_ERR(cec->cec_gpio);
+	cec->cec_irq = gpiod_to_irq(cec->cec_gpio);
+
+	cec->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
+	if (IS_ERR(cec->hpd_gpio))
+		return PTR_ERR(cec->hpd_gpio);
+
+	cec->adap = cec_pin_allocate_adapter(&cec_gpio_pin_ops,
+		cec, pdev->name, CEC_CAP_DEFAULTS | CEC_CAP_PHYS_ADDR |
+				 CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN);
+	if (IS_ERR(cec->adap))
+		return PTR_ERR(cec->adap);
+
+	if (cec->hpd_gpio) {
+		cec->hpd_irq = gpiod_to_irq(cec->hpd_gpio);
+		ret = devm_request_threaded_irq(dev, cec->hpd_irq,
+			cec_hpd_gpio_irq_handler,
+			cec_hpd_gpio_irq_handler_thread,
+			IRQF_ONESHOT |
+			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+			"hpd-gpio", cec);
+		if (ret)
+			return ret;
+	}
+
+	ret = cec_register_adapter(cec->adap, &pdev->dev);
+	if (ret) {
+		cec_delete_adapter(cec->adap);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, cec);
+	return 0;
+}
+
+static int cec_gpio_remove(struct platform_device *pdev)
+{
+	struct cec_gpio *cec = platform_get_drvdata(pdev);
+
+	cec_unregister_adapter(cec->adap);
+	return 0;
+}
+
+static const struct of_device_id cec_gpio_match[] = {
+	{
+		.compatible	= "cec-gpio",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, cec_gpio_match);
+
+static struct platform_driver cec_gpio_pdrv = {
+	.probe	= cec_gpio_probe,
+	.remove = cec_gpio_remove,
+	.driver = {
+		.name		= "cec-gpio",
+		.of_match_table	= cec_gpio_match,
+	},
+};
+
+module_platform_driver(cec_gpio_pdrv);
+
+MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("CEC GPIO driver");
-- 
2.14.1

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 5/5] MAINTAINERS: add cec-gpio entry
  2017-08-31 11:01 ` Hans Verkuil
@ 2017-08-31 11:01   ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: devicetree, Hans Verkuil, dri-devel

From: Hans Verkuil <hans.verkuil@cisco.com>

Add an entry for the CEC GPIO driver.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 MAINTAINERS | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index eb930ebecfcb..5ef0d34ef502 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3205,6 +3205,15 @@ F:	include/uapi/linux/cec.h
 F:	include/uapi/linux/cec-funcs.h
 F:	Documentation/devicetree/bindings/media/cec.txt
 
+CEC GPIO DRIVER
+M:	Hans Verkuil <hans.verkuil@cisco.com>
+L:	linux-media@vger.kernel.org
+T:	git git://linuxtv.org/media_tree.git
+W:	http://linuxtv.org
+S:	Supported
+F:	drivers/media/platform/cec-gpio/
+F:	Documentation/devicetree/bindings/media/cec-gpio.txt
+
 CELL BROADBAND ENGINE ARCHITECTURE
 M:	Arnd Bergmann <arnd@arndb.de>
 L:	linuxppc-dev@lists.ozlabs.org
-- 
2.14.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCHv4 5/5] MAINTAINERS: add cec-gpio entry
@ 2017-08-31 11:01   ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 11:01 UTC (permalink / raw)
  To: linux-media; +Cc: dri-devel, devicetree, Linus Walleij, Hans Verkuil

From: Hans Verkuil <hans.verkuil@cisco.com>

Add an entry for the CEC GPIO driver.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 MAINTAINERS | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index eb930ebecfcb..5ef0d34ef502 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3205,6 +3205,15 @@ F:	include/uapi/linux/cec.h
 F:	include/uapi/linux/cec-funcs.h
 F:	Documentation/devicetree/bindings/media/cec.txt
 
+CEC GPIO DRIVER
+M:	Hans Verkuil <hans.verkuil@cisco.com>
+L:	linux-media@vger.kernel.org
+T:	git git://linuxtv.org/media_tree.git
+W:	http://linuxtv.org
+S:	Supported
+F:	drivers/media/platform/cec-gpio/
+F:	Documentation/devicetree/bindings/media/cec-gpio.txt
+
 CELL BROADBAND ENGINE ARCHITECTURE
 M:	Arnd Bergmann <arnd@arndb.de>
 L:	linuxppc-dev@lists.ozlabs.org
-- 
2.14.1

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-08-31 11:01     ` Hans Verkuil
@ 2017-08-31 14:07         ` Linus Walleij
  -1 siblings, 0 replies; 27+ messages in thread
From: Linus Walleij @ 2017-08-31 14:07 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media-u79uwXL29TY76Z2rM5mHXA, open list:DRM PANEL DRIVERS,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Hans Verkuil

On Thu, Aug 31, 2017 at 1:01 PM, Hans Verkuil <hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org> wrote:

> From: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
>
> Document the bindings for the cec-gpio module for hardware where the
> CEC line and optionally the HPD line are connected to GPIO lines.
>
> Signed-off-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>

Reviewed-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
@ 2017-08-31 14:07         ` Linus Walleij
  0 siblings, 0 replies; 27+ messages in thread
From: Linus Walleij @ 2017-08-31 14:07 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media, open list:DRM PANEL DRIVERS, devicetree, Hans Verkuil

On Thu, Aug 31, 2017 at 1:01 PM, Hans Verkuil <hverkuil@xs4all.nl> wrote:

> From: Hans Verkuil <hans.verkuil@cisco.com>
>
> Document the bindings for the cec-gpio module for hardware where the
> CEC line and optionally the HPD line are connected to GPIO lines.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 4/5] cec-gpio: add HDMI CEC GPIO driver
  2017-08-31 11:01   ` Hans Verkuil
  (?)
@ 2017-08-31 14:10   ` Linus Walleij
       [not found]     ` <CACRpkdYQSYMQHgrOimV6iVRdrjhAXvXdzsfnNr8abykOyZP8yw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
  -1 siblings, 1 reply; 27+ messages in thread
From: Linus Walleij @ 2017-08-31 14:10 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media, open list:DRM PANEL DRIVERS, devicetree, Hans Verkuil

On Thu, Aug 31, 2017 at 1:01 PM, Hans Verkuil <hverkuil@xs4all.nl> wrote:

> From: Hans Verkuil <hans.verkuil@cisco.com>
>
> Add a simple HDMI CEC GPIO driver that sits on top of the cec-pin framework.
>
> While I have heard of SoCs that use the GPIO pin for CEC (apparently an
> early RockChip SoC used that), the main use-case of this driver is to
> function as a debugging tool.
>
> By connecting the CEC line to a GPIO pin on a Raspberry Pi 3 for example
> it turns it into a CEC debugger and protocol analyzer.
>
> With 'cec-ctl --monitor-pin' the CEC traffic can be analyzed.
>
> But of course it can also be used with any hardware project where the
> HDMI CEC line is hooked up to a pull-up gpio line.
>
> In addition this has (optional) support for tracing HPD changes if the
> HPD is connected to a GPIO.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>

This looks nice!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 4/5] cec-gpio: add HDMI CEC GPIO driver
  2017-08-31 14:10   ` Linus Walleij
@ 2017-08-31 14:19         ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 14:19 UTC (permalink / raw)
  To: Linus Walleij
  Cc: linux-media-u79uwXL29TY76Z2rM5mHXA, open list:DRM PANEL DRIVERS,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Hans Verkuil

On 31/08/17 16:10, Linus Walleij wrote:
> On Thu, Aug 31, 2017 at 1:01 PM, Hans Verkuil <hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org> wrote:
> 
>> From: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
>>
>> Add a simple HDMI CEC GPIO driver that sits on top of the cec-pin framework.
>>
>> While I have heard of SoCs that use the GPIO pin for CEC (apparently an
>> early RockChip SoC used that), the main use-case of this driver is to
>> function as a debugging tool.
>>
>> By connecting the CEC line to a GPIO pin on a Raspberry Pi 3 for example
>> it turns it into a CEC debugger and protocol analyzer.
>>
>> With 'cec-ctl --monitor-pin' the CEC traffic can be analyzed.
>>
>> But of course it can also be used with any hardware project where the
>> HDMI CEC line is hooked up to a pull-up gpio line.
>>
>> In addition this has (optional) support for tracing HPD changes if the
>> HPD is connected to a GPIO.
>>
>> Signed-off-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
> 
> This looks nice!
> Reviewed-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

Thank you for the gpio crash course! :-)

	Hans

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 4/5] cec-gpio: add HDMI CEC GPIO driver
@ 2017-08-31 14:19         ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-08-31 14:19 UTC (permalink / raw)
  To: Linus Walleij
  Cc: linux-media, open list:DRM PANEL DRIVERS, devicetree, Hans Verkuil

On 31/08/17 16:10, Linus Walleij wrote:
> On Thu, Aug 31, 2017 at 1:01 PM, Hans Verkuil <hverkuil@xs4all.nl> wrote:
> 
>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>
>> Add a simple HDMI CEC GPIO driver that sits on top of the cec-pin framework.
>>
>> While I have heard of SoCs that use the GPIO pin for CEC (apparently an
>> early RockChip SoC used that), the main use-case of this driver is to
>> function as a debugging tool.
>>
>> By connecting the CEC line to a GPIO pin on a Raspberry Pi 3 for example
>> it turns it into a CEC debugger and protocol analyzer.
>>
>> With 'cec-ctl --monitor-pin' the CEC traffic can be analyzed.
>>
>> But of course it can also be used with any hardware project where the
>> HDMI CEC line is hooked up to a pull-up gpio line.
>>
>> In addition this has (optional) support for tracing HPD changes if the
>> HPD is connected to a GPIO.
>>
>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> 
> This looks nice!
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Thank you for the gpio crash course! :-)

	Hans

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-08-31 11:01     ` Hans Verkuil
  (?)
@ 2017-09-11  7:42     ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-09-11  7:42 UTC (permalink / raw)
  To: linux-media; +Cc: dri-devel, devicetree, Linus Walleij, Hans Verkuil

Ping!

Still waiting for an Ack from the devicetree devs so this can be merged for 4.15.

Regards,

	Hans

On 08/31/2017 01:01 PM, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Document the bindings for the cec-gpio module for hardware where the
> CEC line and optionally the HPD line are connected to GPIO lines.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
> new file mode 100644
> index 000000000000..db20a7452dbd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
> @@ -0,0 +1,22 @@
> +* HDMI CEC GPIO driver
> +
> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
> +hooked up to another GPIO line.
> +
> +Required properties:
> +  - compatible: value must be "cec-gpio"
> +  - cec-gpio: gpio that the CEC line is connected to
> +
> +Optional property:
> +  - hpd-gpio: gpio that the HPD line is connected to
> +
> +Example for the Raspberry Pi 3 where the CEC line is connected to
> +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
> +connected to pin 11 aka BCM17:
> +
> +cec-gpio@7 {
> +       compatible = "cec-gpio";
> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
> +       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
> +};
> 

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-08-31 11:01     ` Hans Verkuil
@ 2017-09-11 20:56         ` Linus Walleij
  -1 siblings, 0 replies; 27+ messages in thread
From: Linus Walleij @ 2017-09-11 20:56 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media-u79uwXL29TY76Z2rM5mHXA, open list:DRM PANEL DRIVERS,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Hans Verkuil

On Thu, Aug 31, 2017 at 1:01 PM, Hans Verkuil <hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org> wrote:

> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;

Actually if you want to be 100% specific:

cec-gpio = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;

(Parens are needed.)

But I'm not very picky about that, active high is implicit.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
@ 2017-09-11 20:56         ` Linus Walleij
  0 siblings, 0 replies; 27+ messages in thread
From: Linus Walleij @ 2017-09-11 20:56 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media, open list:DRM PANEL DRIVERS, devicetree, Hans Verkuil

On Thu, Aug 31, 2017 at 1:01 PM, Hans Verkuil <hverkuil@xs4all.nl> wrote:

> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;

Actually if you want to be 100% specific:

cec-gpio = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;

(Parens are needed.)

But I'm not very picky about that, active high is implicit.

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-08-31 11:01     ` Hans Verkuil
@ 2017-09-12 14:43         ` Rob Herring
  -1 siblings, 0 replies; 27+ messages in thread
From: Rob Herring @ 2017-09-12 14:43 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media-u79uwXL29TY76Z2rM5mHXA,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Linus Walleij, Hans Verkuil

On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
> 
> Document the bindings for the cec-gpio module for hardware where the
> CEC line and optionally the HPD line are connected to GPIO lines.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
> ---
>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
> new file mode 100644
> index 000000000000..db20a7452dbd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
> @@ -0,0 +1,22 @@
> +* HDMI CEC GPIO driver
> +
> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
> +hooked up to another GPIO line.
> +
> +Required properties:
> +  - compatible: value must be "cec-gpio"
> +  - cec-gpio: gpio that the CEC line is connected to

cec-gpios

> +
> +Optional property:
> +  - hpd-gpio: gpio that the HPD line is connected to

hpd-gpios

However, HPD is already part of the HDMI connector binding. Having it in 
2 places would be wrong.

I think we should have either:

hdmi-connector {
	compatible = 'hdmi-connector-a";
	hpd-gpios = <...>;
	cec-gpios = <...>;
	ports {
		// port to HDMI controller
	...
	};
};

Or:

hdmi-connector {
        compatible = 'hdmi-connector-a";
        hpd-gpios = <...>;
        cec = <&cec>;
        ... 
};

cec: cec-gpio {
	compatible = "cec-gpio";
	cec-gpios = <...>;
};

My preference is probably the former. The latter just helps create a 
device to bind to a driver, but DT is not the only way to create 
devices. Then again, if you have a phandle to real CEC controllers in 
the HDMI connector node, it may make sense to do the same thing with 
cec-gpio. 

> +
> +Example for the Raspberry Pi 3 where the CEC line is connected to
> +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
> +connected to pin 11 aka BCM17:
> +
> +cec-gpio@7 {

unit address is not valid. Build your dts's with W=2.

> +       compatible = "cec-gpio";
> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
> +       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
> +};
> -- 
> 2.14.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe devicetree" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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--
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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
@ 2017-09-12 14:43         ` Rob Herring
  0 siblings, 0 replies; 27+ messages in thread
From: Rob Herring @ 2017-09-12 14:43 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media, dri-devel, devicetree, Linus Walleij, Hans Verkuil

On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Document the bindings for the cec-gpio module for hardware where the
> CEC line and optionally the HPD line are connected to GPIO lines.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
> new file mode 100644
> index 000000000000..db20a7452dbd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
> @@ -0,0 +1,22 @@
> +* HDMI CEC GPIO driver
> +
> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
> +hooked up to another GPIO line.
> +
> +Required properties:
> +  - compatible: value must be "cec-gpio"
> +  - cec-gpio: gpio that the CEC line is connected to

cec-gpios

> +
> +Optional property:
> +  - hpd-gpio: gpio that the HPD line is connected to

hpd-gpios

However, HPD is already part of the HDMI connector binding. Having it in 
2 places would be wrong.

I think we should have either:

hdmi-connector {
	compatible = 'hdmi-connector-a";
	hpd-gpios = <...>;
	cec-gpios = <...>;
	ports {
		// port to HDMI controller
	...
	};
};

Or:

hdmi-connector {
        compatible = 'hdmi-connector-a";
        hpd-gpios = <...>;
        cec = <&cec>;
        ... 
};

cec: cec-gpio {
	compatible = "cec-gpio";
	cec-gpios = <...>;
};

My preference is probably the former. The latter just helps create a 
device to bind to a driver, but DT is not the only way to create 
devices. Then again, if you have a phandle to real CEC controllers in 
the HDMI connector node, it may make sense to do the same thing with 
cec-gpio. 

> +
> +Example for the Raspberry Pi 3 where the CEC line is connected to
> +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
> +connected to pin 11 aka BCM17:
> +
> +cec-gpio@7 {

unit address is not valid. Build your dts's with W=2.

> +       compatible = "cec-gpio";
> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
> +       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
> +};
> -- 
> 2.14.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe devicetree" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-09-12 14:43         ` Rob Herring
@ 2017-09-13  8:21           ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-09-13  8:21 UTC (permalink / raw)
  To: Rob Herring; +Cc: devicetree, Hans Verkuil, dri-devel, linux-media

On 09/12/2017 04:43 PM, Rob Herring wrote:
> On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>
>> Document the bindings for the cec-gpio module for hardware where the
>> CEC line and optionally the HPD line are connected to GPIO lines.
>>
>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>> ---
>>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>>  1 file changed, 22 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
>>
>> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
>> new file mode 100644
>> index 000000000000..db20a7452dbd
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
>> @@ -0,0 +1,22 @@
>> +* HDMI CEC GPIO driver
>> +
>> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
>> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
>> +hooked up to another GPIO line.
>> +
>> +Required properties:
>> +  - compatible: value must be "cec-gpio"
>> +  - cec-gpio: gpio that the CEC line is connected to
> 
> cec-gpios

Will change.

> 
>> +
>> +Optional property:
>> +  - hpd-gpio: gpio that the HPD line is connected to
> 
> hpd-gpios

Will change.

> 
> However, HPD is already part of the HDMI connector binding. Having it in 
> 2 places would be wrong.

No. This is not an HDMI receiver/transmitter. There are two use-cases for this
driver:

1) For HDMI receivers/transmitters that connect the CEC pin of an HDMI connector
   to a GPIO pin. In that case the HPD goes to the HDMI transmitter/receiver and
   not to this driver. As you say, that would not make any sense.

   But currently no such devices are in the kernel (I know they exist, though).
   Once such a driver would appear in the kernel then these bindings need to be
   extended with an hdmi-phandle.

2) This driver is used for debugging CEC like this:

	https://hverkuil.home.xs4all.nl/rpi3-cec.jpg

   Here the CEC pin of an HDMI breakout connector is hooked up to a Raspberry Pi
   GPIO pin and the RPi monitors it. It's a cheap but very effective CEC analyzer.
   In this use-case it is very helpful to also monitor the HPD pin since some
   displays do weird things with the HPD and knowing the state of the HPD helps
   a lot when debugging CEC problems. It's optional and it only monitors the pin.

   Actually, there does not have to be an HDMI connector involved at all: you can
   make two cec-gpio instances and just connect the two GPIO pins together in
   order to emulate two CEC adapters and play with that.

> 
> I think we should have either:
> 
> hdmi-connector {
> 	compatible = 'hdmi-connector-a";
> 	hpd-gpios = <...>;
> 	cec-gpios = <...>;
> 	ports {
> 		// port to HDMI controller
> 	...
> 	};
> };
> 
> Or:
> 
> hdmi-connector {
>         compatible = 'hdmi-connector-a";
>         hpd-gpios = <...>;
>         cec = <&cec>;
>         ... 
> };
> 
> cec: cec-gpio {
> 	compatible = "cec-gpio";
> 	cec-gpios = <...>;
> };
> 
> My preference is probably the former. The latter just helps create a 
> device to bind to a driver, but DT is not the only way to create 
> devices. Then again, if you have a phandle to real CEC controllers in 
> the HDMI connector node, it may make sense to do the same thing with 
> cec-gpio. 
> 
>> +
>> +Example for the Raspberry Pi 3 where the CEC line is connected to
>> +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
>> +connected to pin 11 aka BCM17:
>> +
>> +cec-gpio@7 {
> 
> unit address is not valid. Build your dts's with W=2.

I'll do that.

> 
>> +       compatible = "cec-gpio";
>> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
>> +       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
>> +};
>> -- 
>> 2.14.1

Regards,

	Hans
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
@ 2017-09-13  8:21           ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-09-13  8:21 UTC (permalink / raw)
  To: Rob Herring
  Cc: linux-media, dri-devel, devicetree, Linus Walleij, Hans Verkuil

On 09/12/2017 04:43 PM, Rob Herring wrote:
> On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>
>> Document the bindings for the cec-gpio module for hardware where the
>> CEC line and optionally the HPD line are connected to GPIO lines.
>>
>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>> ---
>>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>>  1 file changed, 22 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
>>
>> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
>> new file mode 100644
>> index 000000000000..db20a7452dbd
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
>> @@ -0,0 +1,22 @@
>> +* HDMI CEC GPIO driver
>> +
>> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
>> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
>> +hooked up to another GPIO line.
>> +
>> +Required properties:
>> +  - compatible: value must be "cec-gpio"
>> +  - cec-gpio: gpio that the CEC line is connected to
> 
> cec-gpios

Will change.

> 
>> +
>> +Optional property:
>> +  - hpd-gpio: gpio that the HPD line is connected to
> 
> hpd-gpios

Will change.

> 
> However, HPD is already part of the HDMI connector binding. Having it in 
> 2 places would be wrong.

No. This is not an HDMI receiver/transmitter. There are two use-cases for this
driver:

1) For HDMI receivers/transmitters that connect the CEC pin of an HDMI connector
   to a GPIO pin. In that case the HPD goes to the HDMI transmitter/receiver and
   not to this driver. As you say, that would not make any sense.

   But currently no such devices are in the kernel (I know they exist, though).
   Once such a driver would appear in the kernel then these bindings need to be
   extended with an hdmi-phandle.

2) This driver is used for debugging CEC like this:

	https://hverkuil.home.xs4all.nl/rpi3-cec.jpg

   Here the CEC pin of an HDMI breakout connector is hooked up to a Raspberry Pi
   GPIO pin and the RPi monitors it. It's a cheap but very effective CEC analyzer.
   In this use-case it is very helpful to also monitor the HPD pin since some
   displays do weird things with the HPD and knowing the state of the HPD helps
   a lot when debugging CEC problems. It's optional and it only monitors the pin.

   Actually, there does not have to be an HDMI connector involved at all: you can
   make two cec-gpio instances and just connect the two GPIO pins together in
   order to emulate two CEC adapters and play with that.

> 
> I think we should have either:
> 
> hdmi-connector {
> 	compatible = 'hdmi-connector-a";
> 	hpd-gpios = <...>;
> 	cec-gpios = <...>;
> 	ports {
> 		// port to HDMI controller
> 	...
> 	};
> };
> 
> Or:
> 
> hdmi-connector {
>         compatible = 'hdmi-connector-a";
>         hpd-gpios = <...>;
>         cec = <&cec>;
>         ... 
> };
> 
> cec: cec-gpio {
> 	compatible = "cec-gpio";
> 	cec-gpios = <...>;
> };
> 
> My preference is probably the former. The latter just helps create a 
> device to bind to a driver, but DT is not the only way to create 
> devices. Then again, if you have a phandle to real CEC controllers in 
> the HDMI connector node, it may make sense to do the same thing with 
> cec-gpio. 
> 
>> +
>> +Example for the Raspberry Pi 3 where the CEC line is connected to
>> +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
>> +connected to pin 11 aka BCM17:
>> +
>> +cec-gpio@7 {
> 
> unit address is not valid. Build your dts's with W=2.

I'll do that.

> 
>> +       compatible = "cec-gpio";
>> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
>> +       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
>> +};
>> -- 
>> 2.14.1

Regards,

	Hans

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-09-13  8:21           ` Hans Verkuil
@ 2017-09-15  8:40               ` Hans Verkuil
  -1 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-09-15  8:40 UTC (permalink / raw)
  To: Rob Herring
  Cc: linux-media-u79uwXL29TY76Z2rM5mHXA,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Linus Walleij, Hans Verkuil

Hi Rob,

On 09/13/17 10:21, Hans Verkuil wrote:
> On 09/12/2017 04:43 PM, Rob Herring wrote:
>> On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
>>> From: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
>>>
>>> Document the bindings for the cec-gpio module for hardware where the
>>> CEC line and optionally the HPD line are connected to GPIO lines.
>>>
>>> Signed-off-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
>>> ---
>>>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>>>  1 file changed, 22 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>> new file mode 100644
>>> index 000000000000..db20a7452dbd
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>> @@ -0,0 +1,22 @@
>>> +* HDMI CEC GPIO driver
>>> +
>>> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
>>> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
>>> +hooked up to another GPIO line.
>>> +
>>> +Required properties:
>>> +  - compatible: value must be "cec-gpio"
>>> +  - cec-gpio: gpio that the CEC line is connected to
>>
>> cec-gpios
> 
> Will change.
> 
>>
>>> +
>>> +Optional property:
>>> +  - hpd-gpio: gpio that the HPD line is connected to
>>
>> hpd-gpios
> 
> Will change.
> 
>>
>> However, HPD is already part of the HDMI connector binding. Having it in 
>> 2 places would be wrong.
> 
> No. This is not an HDMI receiver/transmitter. There are two use-cases for this
> driver:
> 
> 1) For HDMI receivers/transmitters that connect the CEC pin of an HDMI connector
>    to a GPIO pin. In that case the HPD goes to the HDMI transmitter/receiver and
>    not to this driver. As you say, that would not make any sense.
> 
>    But currently no such devices are in the kernel (I know they exist, though).
>    Once such a driver would appear in the kernel then these bindings need to be
>    extended with an hdmi-phandle.
> 
> 2) This driver is used for debugging CEC like this:
> 
> 	https://hverkuil.home.xs4all.nl/rpi3-cec.jpg
> 
>    Here the CEC pin of an HDMI breakout connector is hooked up to a Raspberry Pi
>    GPIO pin and the RPi monitors it. It's a cheap but very effective CEC analyzer.
>    In this use-case it is very helpful to also monitor the HPD pin since some
>    displays do weird things with the HPD and knowing the state of the HPD helps
>    a lot when debugging CEC problems. It's optional and it only monitors the pin.
> 
>    Actually, there does not have to be an HDMI connector involved at all: you can
>    make two cec-gpio instances and just connect the two GPIO pins together in
>    order to emulate two CEC adapters and play with that.

Is it OK to define a binding but not (yet) implement it? I have seen that in other
bindings (well, OK, one other binding :-) ). If that is fine, then I can write the
following:

----------------------------------------------------------------
Required properties:
  - compatible: value must be "cec-gpio".
  - cec-gpios: gpio that the CEC line is connected to.

If the CEC line is associated with an HDMI receiver/transmitter, then the following
property is also required:

  - hdmi-phandle - phandle to the HDMI controller, see also cec.txt.

If the CEC line is not associated with an HDMI receiver/transmitter, then the
following property is optional:

  - hpd-gpios: gpio that the HPD line is connected to.
----------------------------------------------------------------

I have plans to support hdmi-phandle in the driver, but that probably won't be ready
in time for 4.15.

Regards,

	Hans

> 
>>
>> I think we should have either:
>>
>> hdmi-connector {
>> 	compatible = 'hdmi-connector-a";
>> 	hpd-gpios = <...>;
>> 	cec-gpios = <...>;
>> 	ports {
>> 		// port to HDMI controller
>> 	...
>> 	};
>> };
>>
>> Or:
>>
>> hdmi-connector {
>>         compatible = 'hdmi-connector-a";
>>         hpd-gpios = <...>;
>>         cec = <&cec>;
>>         ... 
>> };
>>
>> cec: cec-gpio {
>> 	compatible = "cec-gpio";
>> 	cec-gpios = <...>;
>> };
>>
>> My preference is probably the former. The latter just helps create a 
>> device to bind to a driver, but DT is not the only way to create 
>> devices. Then again, if you have a phandle to real CEC controllers in 
>> the HDMI connector node, it may make sense to do the same thing with 
>> cec-gpio. 
>>
>>> +
>>> +Example for the Raspberry Pi 3 where the CEC line is connected to
>>> +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
>>> +connected to pin 11 aka BCM17:
>>> +
>>> +cec-gpio@7 {
>>
>> unit address is not valid. Build your dts's with W=2.
> 
> I'll do that.
> 
>>
>>> +       compatible = "cec-gpio";
>>> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
>>> +       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
>>> +};
>>> -- 
>>> 2.14.1
> 
> Regards,
> 
> 	Hans
> 

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
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More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
@ 2017-09-15  8:40               ` Hans Verkuil
  0 siblings, 0 replies; 27+ messages in thread
From: Hans Verkuil @ 2017-09-15  8:40 UTC (permalink / raw)
  To: Rob Herring
  Cc: linux-media, dri-devel, devicetree, Linus Walleij, Hans Verkuil

Hi Rob,

On 09/13/17 10:21, Hans Verkuil wrote:
> On 09/12/2017 04:43 PM, Rob Herring wrote:
>> On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
>>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>>
>>> Document the bindings for the cec-gpio module for hardware where the
>>> CEC line and optionally the HPD line are connected to GPIO lines.
>>>
>>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>>> ---
>>>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>>>  1 file changed, 22 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>> new file mode 100644
>>> index 000000000000..db20a7452dbd
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>> @@ -0,0 +1,22 @@
>>> +* HDMI CEC GPIO driver
>>> +
>>> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
>>> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
>>> +hooked up to another GPIO line.
>>> +
>>> +Required properties:
>>> +  - compatible: value must be "cec-gpio"
>>> +  - cec-gpio: gpio that the CEC line is connected to
>>
>> cec-gpios
> 
> Will change.
> 
>>
>>> +
>>> +Optional property:
>>> +  - hpd-gpio: gpio that the HPD line is connected to
>>
>> hpd-gpios
> 
> Will change.
> 
>>
>> However, HPD is already part of the HDMI connector binding. Having it in 
>> 2 places would be wrong.
> 
> No. This is not an HDMI receiver/transmitter. There are two use-cases for this
> driver:
> 
> 1) For HDMI receivers/transmitters that connect the CEC pin of an HDMI connector
>    to a GPIO pin. In that case the HPD goes to the HDMI transmitter/receiver and
>    not to this driver. As you say, that would not make any sense.
> 
>    But currently no such devices are in the kernel (I know they exist, though).
>    Once such a driver would appear in the kernel then these bindings need to be
>    extended with an hdmi-phandle.
> 
> 2) This driver is used for debugging CEC like this:
> 
> 	https://hverkuil.home.xs4all.nl/rpi3-cec.jpg
> 
>    Here the CEC pin of an HDMI breakout connector is hooked up to a Raspberry Pi
>    GPIO pin and the RPi monitors it. It's a cheap but very effective CEC analyzer.
>    In this use-case it is very helpful to also monitor the HPD pin since some
>    displays do weird things with the HPD and knowing the state of the HPD helps
>    a lot when debugging CEC problems. It's optional and it only monitors the pin.
> 
>    Actually, there does not have to be an HDMI connector involved at all: you can
>    make two cec-gpio instances and just connect the two GPIO pins together in
>    order to emulate two CEC adapters and play with that.

Is it OK to define a binding but not (yet) implement it? I have seen that in other
bindings (well, OK, one other binding :-) ). If that is fine, then I can write the
following:

----------------------------------------------------------------
Required properties:
  - compatible: value must be "cec-gpio".
  - cec-gpios: gpio that the CEC line is connected to.

If the CEC line is associated with an HDMI receiver/transmitter, then the following
property is also required:

  - hdmi-phandle - phandle to the HDMI controller, see also cec.txt.

If the CEC line is not associated with an HDMI receiver/transmitter, then the
following property is optional:

  - hpd-gpios: gpio that the HPD line is connected to.
----------------------------------------------------------------

I have plans to support hdmi-phandle in the driver, but that probably won't be ready
in time for 4.15.

Regards,

	Hans

> 
>>
>> I think we should have either:
>>
>> hdmi-connector {
>> 	compatible = 'hdmi-connector-a";
>> 	hpd-gpios = <...>;
>> 	cec-gpios = <...>;
>> 	ports {
>> 		// port to HDMI controller
>> 	...
>> 	};
>> };
>>
>> Or:
>>
>> hdmi-connector {
>>         compatible = 'hdmi-connector-a";
>>         hpd-gpios = <...>;
>>         cec = <&cec>;
>>         ... 
>> };
>>
>> cec: cec-gpio {
>> 	compatible = "cec-gpio";
>> 	cec-gpios = <...>;
>> };
>>
>> My preference is probably the former. The latter just helps create a 
>> device to bind to a driver, but DT is not the only way to create 
>> devices. Then again, if you have a phandle to real CEC controllers in 
>> the HDMI connector node, it may make sense to do the same thing with 
>> cec-gpio. 
>>
>>> +
>>> +Example for the Raspberry Pi 3 where the CEC line is connected to
>>> +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is
>>> +connected to pin 11 aka BCM17:
>>> +
>>> +cec-gpio@7 {
>>
>> unit address is not valid. Build your dts's with W=2.
> 
> I'll do that.
> 
>>
>>> +       compatible = "cec-gpio";
>>> +       cec-gpio = <&gpio 7 GPIO_OPEN_DRAIN>;
>>> +       hpd-gpio = <&gpio 17 GPIO_ACTIVE_HIGH>;
>>> +};
>>> -- 
>>> 2.14.1
> 
> Regards,
> 
> 	Hans
> 

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
  2017-09-15  8:40               ` Hans Verkuil
@ 2017-09-15 18:14                   ` Rob Herring
  -1 siblings, 0 replies; 27+ messages in thread
From: Rob Herring @ 2017-09-15 18:14 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media-u79uwXL29TY76Z2rM5mHXA, dri-devel,
	devicetree-u79uwXL29TY76Z2rM5mHXA, Linus Walleij, Hans Verkuil

On Fri, Sep 15, 2017 at 3:40 AM, Hans Verkuil <hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org> wrote:
> Hi Rob,
>
> On 09/13/17 10:21, Hans Verkuil wrote:
>> On 09/12/2017 04:43 PM, Rob Herring wrote:
>>> On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
>>>> From: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
>>>>
>>>> Document the bindings for the cec-gpio module for hardware where the
>>>> CEC line and optionally the HPD line are connected to GPIO lines.
>>>>
>>>> Signed-off-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
>>>> ---
>>>>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>>>>  1 file changed, 22 insertions(+)
>>>>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>>> new file mode 100644
>>>> index 000000000000..db20a7452dbd
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>>> @@ -0,0 +1,22 @@
>>>> +* HDMI CEC GPIO driver
>>>> +
>>>> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
>>>> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
>>>> +hooked up to another GPIO line.
>>>> +
>>>> +Required properties:
>>>> +  - compatible: value must be "cec-gpio"
>>>> +  - cec-gpio: gpio that the CEC line is connected to
>>>
>>> cec-gpios
>>
>> Will change.
>>
>>>
>>>> +
>>>> +Optional property:
>>>> +  - hpd-gpio: gpio that the HPD line is connected to
>>>
>>> hpd-gpios
>>
>> Will change.
>>
>>>
>>> However, HPD is already part of the HDMI connector binding. Having it in
>>> 2 places would be wrong.
>>
>> No. This is not an HDMI receiver/transmitter. There are two use-cases for this
>> driver:
>>
>> 1) For HDMI receivers/transmitters that connect the CEC pin of an HDMI connector
>>    to a GPIO pin. In that case the HPD goes to the HDMI transmitter/receiver and
>>    not to this driver. As you say, that would not make any sense.
>>
>>    But currently no such devices are in the kernel (I know they exist, though).
>>    Once such a driver would appear in the kernel then these bindings need to be
>>    extended with an hdmi-phandle.
>>
>> 2) This driver is used for debugging CEC like this:
>>
>>       https://hverkuil.home.xs4all.nl/rpi3-cec.jpg
>>
>>    Here the CEC pin of an HDMI breakout connector is hooked up to a Raspberry Pi
>>    GPIO pin and the RPi monitors it. It's a cheap but very effective CEC analyzer.
>>    In this use-case it is very helpful to also monitor the HPD pin since some
>>    displays do weird things with the HPD and knowing the state of the HPD helps
>>    a lot when debugging CEC problems. It's optional and it only monitors the pin.
>>
>>    Actually, there does not have to be an HDMI connector involved at all: you can
>>    make two cec-gpio instances and just connect the two GPIO pins together in
>>    order to emulate two CEC adapters and play with that.
>
> Is it OK to define a binding but not (yet) implement it? I have seen that in other
> bindings (well, OK, one other binding :-) ). If that is fine, then I can write the
> following:

It's preferred over adding a property one by one.

>
> ----------------------------------------------------------------
> Required properties:
>   - compatible: value must be "cec-gpio".
>   - cec-gpios: gpio that the CEC line is connected to.
>
> If the CEC line is associated with an HDMI receiver/transmitter, then the following
> property is also required:
>
>   - hdmi-phandle - phandle to the HDMI controller, see also cec.txt.
>
> If the CEC line is not associated with an HDMI receiver/transmitter, then the
> following property is optional:
>
>   - hpd-gpios: gpio that the HPD line is connected to.
> ----------------------------------------------------------------

Yes, this seems fine.

Rob
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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings
@ 2017-09-15 18:14                   ` Rob Herring
  0 siblings, 0 replies; 27+ messages in thread
From: Rob Herring @ 2017-09-15 18:14 UTC (permalink / raw)
  To: Hans Verkuil
  Cc: linux-media, dri-devel, devicetree, Linus Walleij, Hans Verkuil

On Fri, Sep 15, 2017 at 3:40 AM, Hans Verkuil <hverkuil@xs4all.nl> wrote:
> Hi Rob,
>
> On 09/13/17 10:21, Hans Verkuil wrote:
>> On 09/12/2017 04:43 PM, Rob Herring wrote:
>>> On Thu, Aug 31, 2017 at 01:01:54PM +0200, Hans Verkuil wrote:
>>>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>>>
>>>> Document the bindings for the cec-gpio module for hardware where the
>>>> CEC line and optionally the HPD line are connected to GPIO lines.
>>>>
>>>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>>>> ---
>>>>  .../devicetree/bindings/media/cec-gpio.txt         | 22 ++++++++++++++++++++++
>>>>  1 file changed, 22 insertions(+)
>>>>  create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>>> new file mode 100644
>>>> index 000000000000..db20a7452dbd
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt
>>>> @@ -0,0 +1,22 @@
>>>> +* HDMI CEC GPIO driver
>>>> +
>>>> +The HDMI CEC GPIO module supports CEC implementations where the CEC line
>>>> +is hooked up to a pull-up GPIO line and - optionally - the HPD line is
>>>> +hooked up to another GPIO line.
>>>> +
>>>> +Required properties:
>>>> +  - compatible: value must be "cec-gpio"
>>>> +  - cec-gpio: gpio that the CEC line is connected to
>>>
>>> cec-gpios
>>
>> Will change.
>>
>>>
>>>> +
>>>> +Optional property:
>>>> +  - hpd-gpio: gpio that the HPD line is connected to
>>>
>>> hpd-gpios
>>
>> Will change.
>>
>>>
>>> However, HPD is already part of the HDMI connector binding. Having it in
>>> 2 places would be wrong.
>>
>> No. This is not an HDMI receiver/transmitter. There are two use-cases for this
>> driver:
>>
>> 1) For HDMI receivers/transmitters that connect the CEC pin of an HDMI connector
>>    to a GPIO pin. In that case the HPD goes to the HDMI transmitter/receiver and
>>    not to this driver. As you say, that would not make any sense.
>>
>>    But currently no such devices are in the kernel (I know they exist, though).
>>    Once such a driver would appear in the kernel then these bindings need to be
>>    extended with an hdmi-phandle.
>>
>> 2) This driver is used for debugging CEC like this:
>>
>>       https://hverkuil.home.xs4all.nl/rpi3-cec.jpg
>>
>>    Here the CEC pin of an HDMI breakout connector is hooked up to a Raspberry Pi
>>    GPIO pin and the RPi monitors it. It's a cheap but very effective CEC analyzer.
>>    In this use-case it is very helpful to also monitor the HPD pin since some
>>    displays do weird things with the HPD and knowing the state of the HPD helps
>>    a lot when debugging CEC problems. It's optional and it only monitors the pin.
>>
>>    Actually, there does not have to be an HDMI connector involved at all: you can
>>    make two cec-gpio instances and just connect the two GPIO pins together in
>>    order to emulate two CEC adapters and play with that.
>
> Is it OK to define a binding but not (yet) implement it? I have seen that in other
> bindings (well, OK, one other binding :-) ). If that is fine, then I can write the
> following:

It's preferred over adding a property one by one.

>
> ----------------------------------------------------------------
> Required properties:
>   - compatible: value must be "cec-gpio".
>   - cec-gpios: gpio that the CEC line is connected to.
>
> If the CEC line is associated with an HDMI receiver/transmitter, then the following
> property is also required:
>
>   - hdmi-phandle - phandle to the HDMI controller, see also cec.txt.
>
> If the CEC line is not associated with an HDMI receiver/transmitter, then the
> following property is optional:
>
>   - hpd-gpios: gpio that the HPD line is connected to.
> ----------------------------------------------------------------

Yes, this seems fine.

Rob

^ permalink raw reply	[flat|nested] 27+ messages in thread
end of thread, other threads:[~2017-09-15 18:14 UTC | newest]

Thread overview: 27+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-08-31 11:01 [PATCHv4 0/5] cec-gpio: add HDMI CEC GPIO-based driver Hans Verkuil
2017-08-31 11:01 ` Hans Verkuil
2017-08-31 11:01 ` [PATCHv4 1/5] cec: add CEC_EVENT_PIN_HPD_LOW/HIGH events Hans Verkuil
     [not found] ` <20170831110156.11018-1-hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org>
2017-08-31 11:01   ` [PATCHv4 2/5] cec-ioc-dqevent.rst: document new " Hans Verkuil
2017-08-31 11:01     ` Hans Verkuil
2017-08-31 11:01   ` [PATCHv4 3/5] dt-bindings: document the CEC GPIO bindings Hans Verkuil
2017-08-31 11:01     ` Hans Verkuil
2017-09-11  7:42     ` Hans Verkuil
     [not found]     ` <20170831110156.11018-4-hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org>
2017-08-31 14:07       ` Linus Walleij
2017-08-31 14:07         ` Linus Walleij
2017-09-11 20:56       ` Linus Walleij
2017-09-11 20:56         ` Linus Walleij
2017-09-12 14:43       ` Rob Herring
2017-09-12 14:43         ` Rob Herring
2017-09-13  8:21         ` Hans Verkuil
2017-09-13  8:21           ` Hans Verkuil
     [not found]           ` <30a2fa9d-1aa9-84c1-7842-05167eee73d3-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org>
2017-09-15  8:40             ` Hans Verkuil
2017-09-15  8:40               ` Hans Verkuil
     [not found]               ` <89739d22-bce2-e31e-fd00-5e7c2fae2148-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org>
2017-09-15 18:14                 ` Rob Herring
2017-09-15 18:14                   ` Rob Herring
2017-08-31 11:01 ` [PATCHv4 4/5] cec-gpio: add HDMI CEC GPIO driver Hans Verkuil
2017-08-31 11:01   ` Hans Verkuil
2017-08-31 14:10   ` Linus Walleij
     [not found]     ` <CACRpkdYQSYMQHgrOimV6iVRdrjhAXvXdzsfnNr8abykOyZP8yw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-08-31 14:19       ` Hans Verkuil
2017-08-31 14:19         ` Hans Verkuil
2017-08-31 11:01 ` [PATCHv4 5/5] MAINTAINERS: add cec-gpio entry Hans Verkuil
2017-08-31 11:01   ` Hans Verkuil

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