[PATCH v2 2/7] drm/i2c: tda998x: move CEC device initialisation later

[Hans Verkuil]

Hi Russell,

On 08/12/17 12:59, Russell King - ARM Linux wrote:
> On Wed, Dec 06, 2017 at 02:54:04PM +0100, Hans Verkuil wrote:
>> On 12/06/17 13:35, Russell King wrote:
>>> We no longer use the CEC client to access the CEC part itself, so we can
>>> move this later in the initialisation sequence.
>>>
>>> Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>
>>> ---
>>>  drivers/gpu/drm/i2c/tda998x_drv.c | 7 ++++---
>>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
>>> index 7f4dbca7f7f4..4aeac2127974 100644
>>> --- a/drivers/gpu/drm/i2c/tda998x_drv.c
>>> +++ b/drivers/gpu/drm/i2c/tda998x_drv.c
>>> @@ -1490,9 +1490,6 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
>>>  	priv->cec_addr = 0x34 + (client->addr & 0x03);
>>>  	priv->current_page = 0xff;
>>>  	priv->hdmi = client;
>>> -	priv->cec = i2c_new_dummy(client->adapter, priv->cec_addr);
>>> -	if (!priv->cec)
>>> -		return -ENODEV;
>>>  
>>>  	/* wake up the device: */
>>>  	cec_write(priv, REG_CEC_ENAMODS,
>>> @@ -1546,6 +1543,10 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
>>>  			CEC_FRO_IM_CLK_CTRL_GHOST_DIS | CEC_FRO_IM_CLK_CTRL_IMCLK_SEL);
>>>  
>>>  	/* initialize the optional IRQ */
>>> +	priv->cec = i2c_new_dummy(client->adapter, priv->cec_addr);
>>> +	if (!priv->cec)
>>> +		return -ENODEV;
>>> +
>>
>> I'd move this up to before the 'initialize the optional IRQ' comment, since
>> that should stay with the 'if (client->irq) {' line below.
> 
> I've swapped the order of patches 2 and 3, and moved this further down
> near where we add the real cec device in a later patch.  This is
> starting to get quite different from the patch series that I've tested,
> and as I've already mentioned, testing is not going to happen for a
> while.
> 

I added support for this to am335x-boneblack-common.dtsi (see patch below), but
it doesn't work. I suspect the calibration since I see these messages:

gpio-57 (nxp,calib): gpiod_direction_output: tried to set a GPIO tied to an IRQ as output

Which makes sense. I had a similar case in my cec-gpio driver and I had to completely
free the interrupt before I could set the direction to output.

I do get nice interrupts when a transmit is done, so the interrupt works correctly.
And it correctly detects Ack/Nack.

I looked a bit closer and I see that even without calibration the timings are reasonably
OK: 2.3 ms for a bit period instead of the recommended 2.4 ms. Slightly off but within
margins.

But receiving messages fails: I get no interrupt at all. Not sure if the lack of
calibration is the cause of that, or if it is something else. I can take another look
once the calibration is fixed.

Regards,

	Hans

Signed-off-by: Hans Verkuil <hans.verkuil at cisco.com>
---
diff --git a/arch/arm/boot/dts/am335x-boneblack-common.dtsi b/arch/arm/boot/dts/am335x-boneblack-common.dtsi
index 325daae40278..07e6b36d17c4 100644
--- a/arch/arm/boot/dts/am335x-boneblack-common.dtsi
+++ b/arch/arm/boot/dts/am335x-boneblack-common.dtsi
@@ -7,6 +7,7 @@
  */

 #include <dt-bindings/display/tda998x.h>
+#include <dt-bindings/interrupt-controller/irq.h>

 &ldo3_reg {
 	regulator-min-microvolt = <1800000>;
@@ -91,6 +92,8 @@
 	tda19988: tda19988 {
 		compatible = "nxp,tda998x";
 		reg = <0x70>;
+		nxp,calib-gpios = <&gpio1 25 0>;
+		interrupts-extended = <&gpio1 25 IRQ_TYPE_LEVEL_LOW>;

 		pinctrl-names = "default", "off";
 		pinctrl-0 = <&nxp_hdmi_bonelt_pins>;