Re: [PATCH] drm/bridge: adv7511: Attach to DSI host at probe time
From: Matt Redfearn
Date: Thu Jun 27 2019 - 11:15:02 EST
On 25/06/2019 11:54, Andrzej Hajda wrote:
> On 24.04.2019 15:22, Matt Redfearn wrote:
>> In contrast to all of the DSI panel drivers in drivers/gpu/drm/panel
>> which attach to the DSI host via mipi_dsi_attach() at probe time, the
>> ADV7533 bridge device does not. Instead it defers this to the point that
>> the upstream device connects to its bridge via drm_bridge_attach().
>> The generic Synopsys MIPI DSI host driver does not register it's own
>> drm_bridge until the MIPI DSI has attached. But it does not call
>> drm_bridge_attach() on the downstream device until the upstream device
>> has attached. This leads to a chicken and the egg failure and the DRM
>> pipeline does not complete.
>> Since all other mipi_dsi_device drivers call mipi_dsi_attach() in
>> probe(), make the adv7533 mipi_dsi_device do the same. This ensures that
>> the Synopsys MIPI DSI host registers it's bridge such that it is
>> available for the upstream device to connect to.
>> Signed-off-by: Matt Redfearn <matt.redfearn@xxxxxxxxxx>
>> drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 9 +++++----
>> 1 file changed, 5 insertions(+), 4 deletions(-)
>> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> index e7ddd3e3db9..ea36ac3a3de 100644
>> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> @@ -874,9 +874,6 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge)
>> drm_connector_attach_encoder(&adv->connector, bridge->encoder);
>> - if (adv->type == ADV7533)
>> - ret = adv7533_attach_dsi(adv);
>> if (adv->i2c_main->irq)
>> regmap_write(adv->regmap, ADV7511_REG_INT_ENABLE(0),
>> @@ -1222,7 +1219,11 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
>> adv7511_audio_init(dev, adv7511);
>> - return 0;
>> + if (adv7511->type == ADV7533)
>> + return adv7533_attach_dsi(adv7511);
>> + else
>> + return 0;
> It seems that on failure of adv7533_attach_dsi cleanup is not performed.
Quite right - I will fix and resend.
> Beside this change looks OK, but it would be good to test it on
> platforms with adv7533.
As in the commit message, I needed this change to get the driver to work
at all on a platform with a Synopsys MIPI DSI interface. However I would
be very grateful for feedback from people using the ADV7533 with other
MIPI DSI hosts.