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Date:   Tue, 18 Jul 2023 15:21:07 +0100
From:   Liviu Dudau <liviu.dudau@arm.com>
To:     Faiz Abbas <faiz.abbas@arm.com>
Cc:     linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        airlied@gmail.com, daniel@ffwll.ch
Subject: Re: [PATCH v3] drm/arm/komeda: Remove component framework and add a
 simple encoder
Message-ID: <ZLaf00o7IqrxcJK4@e110455-lin.cambridge.arm.com>
References: <20230712064937.25192-1-faiz.abbas@arm.com>
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In-Reply-To: <20230712064937.25192-1-faiz.abbas@arm.com>
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On Wed, Jul 12, 2023 at 12:19:37PM +0530, Faiz Abbas wrote:
> The Komeda driver always expects the remote connector node to initialize
> an encoder. It uses the component aggregator framework which consists
> of component->bind() calls used to initialize the remote encoder and attach
> it to the crtc. This makes it incompatible with connector drivers which
> implement drm_bridge APIs.
> 
> Remove all component framework calls from the komeda driver and declare and
> attach an encoder inside komeda_crtc_add().
> 
> The remote connector driver has to implement the DRM bridge APIs which
> can be used to glue the encoder to the remote connector. Since we
> usually pair this with a component encoder that also implements a
> drm_bridge, dropping support is not expected to affect users of this
> driver.
> 
> Signed-off-by: Faiz Abbas <faiz.abbas@arm.com>

Sorry for the delay in replying, I thought I already did. Patch looks good
and thanks for the effort.

Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>

I'm going to pull this into drm-misc-next by the end of the week.

Best regards,
Liviu

> ---
> v3 -> v2:
> * Rebased to latest drm-misc-next
> 
> v2 -> v1:
> 
> * Removed additional instances of component APIs
> 
>  .../gpu/drm/arm/display/komeda/komeda_crtc.c  | 23 +++++++-
>  .../gpu/drm/arm/display/komeda/komeda_drv.c   | 55 ++-----------------
>  .../gpu/drm/arm/display/komeda/komeda_kms.c   | 11 +---
>  .../gpu/drm/arm/display/komeda/komeda_kms.h   |  3 +
>  4 files changed, 30 insertions(+), 62 deletions(-)
> 
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> index cea3fd5772b57..b615d625c244f 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
> @@ -12,6 +12,8 @@
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_print.h>
>  #include <drm/drm_vblank.h>
> +#include <drm/drm_simple_kms_helper.h>
> +#include <drm/drm_bridge.h>
>  
>  #include "komeda_dev.h"
>  #include "komeda_kms.h"
> @@ -612,9 +614,11 @@ static int komeda_crtc_add(struct komeda_kms_dev *kms,
>  			   struct komeda_crtc *kcrtc)
>  {
>  	struct drm_crtc *crtc = &kcrtc->base;
> +	struct drm_device *base = &kms->base;
> +	struct drm_bridge *bridge;
>  	int err;
>  
> -	err = drm_crtc_init_with_planes(&kms->base, crtc,
> +	err = drm_crtc_init_with_planes(base, crtc,
>  					get_crtc_primary(kms, kcrtc), NULL,
>  					&komeda_crtc_funcs, NULL);
>  	if (err)
> @@ -624,6 +628,23 @@ static int komeda_crtc_add(struct komeda_kms_dev *kms,
>  
>  	crtc->port = kcrtc->master->of_output_port;
>  
> +
> +	/* Construct an encoder for each pipeline and attach it to the remote
> +	 * bridge
> +	 */
> +	kcrtc->encoder.possible_crtcs = drm_crtc_mask(crtc);
> +	err = drm_simple_encoder_init(base, &kcrtc->encoder,
> +				      DRM_MODE_ENCODER_TMDS);
> +	if (err)
> +		return err;
> +
> +	bridge = devm_drm_of_get_bridge(base->dev, kcrtc->master->of_node,
> +					KOMEDA_OF_PORT_OUTPUT, 0);
> +	if (IS_ERR(bridge))
> +		return PTR_ERR(bridge);
> +
> +	err = drm_bridge_attach(&kcrtc->encoder, bridge, NULL, 0);
> +
>  	drm_crtc_enable_color_mgmt(crtc, 0, true, KOMEDA_COLOR_LUT_SIZE);
>  
>  	return err;
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_drv.c b/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
> index c597c362f6892..cb2a2be24c5ff 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
> @@ -8,7 +8,6 @@
>  #include <linux/kernel.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> -#include <linux/component.h>
>  #include <linux/pm_runtime.h>
>  #include <drm/drm_fbdev_generic.h>
>  #include <drm/drm_module.h>
> @@ -28,13 +27,11 @@ struct komeda_dev *dev_to_mdev(struct device *dev)
>  	return mdrv ? mdrv->mdev : NULL;
>  }
>  
> -static void komeda_unbind(struct device *dev)
> +static void komeda_platform_remove(struct platform_device *pdev)
>  {
> +	struct device *dev = &pdev->dev;
>  	struct komeda_drv *mdrv = dev_get_drvdata(dev);
>  
> -	if (!mdrv)
> -		return;
> -
>  	komeda_kms_detach(mdrv->kms);
>  
>  	if (pm_runtime_enabled(dev))
> @@ -48,8 +45,9 @@ static void komeda_unbind(struct device *dev)
>  	devm_kfree(dev, mdrv);
>  }
>  
> -static int komeda_bind(struct device *dev)
> +static int komeda_platform_probe(struct platform_device *pdev)
>  {
> +	struct device *dev = &pdev->dev;
>  	struct komeda_drv *mdrv;
>  	int err;
>  
> @@ -91,51 +89,6 @@ static int komeda_bind(struct device *dev)
>  	return err;
>  }
>  
> -static const struct component_master_ops komeda_master_ops = {
> -	.bind	= komeda_bind,
> -	.unbind	= komeda_unbind,
> -};
> -
> -static void komeda_add_slave(struct device *master,
> -			     struct component_match **match,
> -			     struct device_node *np,
> -			     u32 port, u32 endpoint)
> -{
> -	struct device_node *remote;
> -
> -	remote = of_graph_get_remote_node(np, port, endpoint);
> -	if (remote) {
> -		drm_of_component_match_add(master, match, component_compare_of, remote);
> -		of_node_put(remote);
> -	}
> -}
> -
> -static int komeda_platform_probe(struct platform_device *pdev)
> -{
> -	struct device *dev = &pdev->dev;
> -	struct component_match *match = NULL;
> -	struct device_node *child;
> -
> -	if (!dev->of_node)
> -		return -ENODEV;
> -
> -	for_each_available_child_of_node(dev->of_node, child) {
> -		if (of_node_cmp(child->name, "pipeline") != 0)
> -			continue;
> -
> -		/* add connector */
> -		komeda_add_slave(dev, &match, child, KOMEDA_OF_PORT_OUTPUT, 0);
> -		komeda_add_slave(dev, &match, child, KOMEDA_OF_PORT_OUTPUT, 1);
> -	}
> -
> -	return component_master_add_with_match(dev, &komeda_master_ops, match);
> -}
> -
> -static void komeda_platform_remove(struct platform_device *pdev)
> -{
> -	component_master_del(&pdev->dev, &komeda_master_ops);
> -}
> -
>  static const struct of_device_id komeda_of_match[] = {
>  	{ .compatible = "arm,mali-d71", .data = d71_identify, },
>  	{ .compatible = "arm,mali-d32", .data = d71_identify, },
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> index 62dc64550793e..9299026701f34 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> @@ -4,7 +4,6 @@
>   * Author: James.Qian.Wang <james.qian.wang@arm.com>
>   *
>   */
> -#include <linux/component.h>
>  #include <linux/interrupt.h>
>  
>  #include <drm/drm_atomic.h>
> @@ -305,17 +304,13 @@ struct komeda_kms_dev *komeda_kms_attach(struct komeda_dev *mdev)
>  	if (err)
>  		goto cleanup_mode_config;
>  
> -	err = component_bind_all(mdev->dev, kms);
> -	if (err)
> -		goto cleanup_mode_config;
> -
>  	drm_mode_config_reset(drm);
>  
>  	err = devm_request_irq(drm->dev, mdev->irq,
>  			       komeda_kms_irq_handler, IRQF_SHARED,
>  			       drm->driver->name, drm);
>  	if (err)
> -		goto free_component_binding;
> +		goto cleanup_mode_config;
>  
>  	drm_kms_helper_poll_init(drm);
>  
> @@ -327,8 +322,6 @@ struct komeda_kms_dev *komeda_kms_attach(struct komeda_dev *mdev)
>  
>  free_interrupts:
>  	drm_kms_helper_poll_fini(drm);
> -free_component_binding:
> -	component_unbind_all(mdev->dev, drm);
>  cleanup_mode_config:
>  	drm_mode_config_cleanup(drm);
>  	komeda_kms_cleanup_private_objs(kms);
> @@ -339,12 +332,10 @@ struct komeda_kms_dev *komeda_kms_attach(struct komeda_dev *mdev)
>  void komeda_kms_detach(struct komeda_kms_dev *kms)
>  {
>  	struct drm_device *drm = &kms->base;
> -	struct komeda_dev *mdev = drm->dev_private;
>  
>  	drm_dev_unregister(drm);
>  	drm_kms_helper_poll_fini(drm);
>  	drm_atomic_helper_shutdown(drm);
> -	component_unbind_all(mdev->dev, drm);
>  	drm_mode_config_cleanup(drm);
>  	komeda_kms_cleanup_private_objs(kms);
>  	drm->dev_private = NULL;
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> index 3a872c2920912..6ef6553263570 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.h
> @@ -84,6 +84,9 @@ struct komeda_crtc {
>  
>  	/** @disable_done: this flip_done is for tracing the disable */
>  	struct completion *disable_done;
> +
> +	/** @encoder: encoder at the end of the pipeline */
> +	struct drm_encoder encoder;
>  };
>  
>  /**
> -- 
> 2.25.1
> 

-- 
====================
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