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Subject: Re: [RESEND PATCH v5 3/3] drm/atmel-hlcdc: support bus-width
 (12/16/18/24) in endpoint nodes
To:     jacopo mondi <jacopo@jmondi.org>
Cc:     linux-kernel@vger.kernel.org,
        Boris Brezillon <boris.brezillon@bootlin.com>,
        David Airlie <airlied@linux.ie>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, Jyri Sarha <jsarha@ti.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Russell King - ARM Linux <linux@armlinux.org.uk>,
        Jacopo Mondi <jacopo+renesas@jmondi.org>
References: <20180803072308.14962-1-peda@axentia.se>
 <20180803072308.14962-4-peda@axentia.se> <20180803081751.GB4528@w540>
From:   Peter Rosin <peda@axentia.se>
Organization: Axentia Technologies AB
Message-ID: <1bedf605-c757-82ab-42e2-7093003bc36e@axentia.se>
Date:   Fri, 3 Aug 2018 10:25:20 +0200
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On 2018-08-03 10:17, jacopo mondi wrote:
> Hi Peter,
> 
> On Fri, Aug 03, 2018 at 09:23:08AM +0200, Peter Rosin wrote:
>> This beats the heuristic that the connector is involved in what format
>> should be output for cases where this fails.
>>
>> E.g. if there is a bridge that changes format between the encoder and the
>> connector, or if some of the RGB pins between the lcd controller and the
>> encoder are not routed on the PCB.
>>
>> This is critical for the devices that have the "conflicting output
>> formats" issue (SAM9N12, SAM9X5, SAMA5D3), since the most significant
>> RGB bits move around depending on the selected output mode. For
>> devices that do not have the "conflicting output formats" issue
>> (SAMA5D2, SAMA5D4), this is completely irrelevant.
>>
>> Acked-by: Boris Brezillon <boris.brezillon@bootlin.com>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
>> ---
>>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c   | 70 +++++++++++++++++-------
>>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h     |  1 +
>>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c | 67 ++++++++++++++++++++---
>>  3 files changed, 111 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
>> index d73281095fac..c38a479ada98 100644
>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
>> @@ -226,6 +226,55 @@ static void atmel_hlcdc_crtc_atomic_enable(struct drm_crtc *c,
>>  #define ATMEL_HLCDC_RGB888_OUTPUT	BIT(3)
>>  #define ATMEL_HLCDC_OUTPUT_MODE_MASK	GENMASK(3, 0)
>>
>> +static int atmel_hlcdc_connector_output_mode(struct drm_connector_state *state)
>> +{
>> +	struct drm_connector *connector = state->connector;
>> +	struct drm_display_info *info = &connector->display_info;
>> +	struct drm_encoder *encoder;
>> +	unsigned int supported_fmts = 0;
>> +	int j;
>> +
>> +	encoder = state->best_encoder;
>> +	if (!encoder)
>> +		encoder = connector->encoder;
>> +
>> +	switch (atmel_hlcdc_encoder_get_bus_fmt(encoder)) {
>> +	case 0:
>> +		break;
>> +	case MEDIA_BUS_FMT_RGB444_1X12:
>> +		return ATMEL_HLCDC_RGB444_OUTPUT;
>> +	case MEDIA_BUS_FMT_RGB565_1X16:
>> +		return ATMEL_HLCDC_RGB565_OUTPUT;
>> +	case MEDIA_BUS_FMT_RGB666_1X18:
>> +		return ATMEL_HLCDC_RGB666_OUTPUT;
>> +	case MEDIA_BUS_FMT_RGB888_1X24:
>> +		return ATMEL_HLCDC_RGB888_OUTPUT;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	for (j = 0; j < info->num_bus_formats; j++) {
>> +		switch (info->bus_formats[j]) {
>> +		case MEDIA_BUS_FMT_RGB444_1X12:
>> +			supported_fmts |= ATMEL_HLCDC_RGB444_OUTPUT;
>> +			break;
>> +		case MEDIA_BUS_FMT_RGB565_1X16:
>> +			supported_fmts |= ATMEL_HLCDC_RGB565_OUTPUT;
>> +			break;
>> +		case MEDIA_BUS_FMT_RGB666_1X18:
>> +			supported_fmts |= ATMEL_HLCDC_RGB666_OUTPUT;
>> +			break;
>> +		case MEDIA_BUS_FMT_RGB888_1X24:
>> +			supported_fmts |= ATMEL_HLCDC_RGB888_OUTPUT;
>> +			break;
>> +		default:
>> +			break;
>> +		}
>> +	}
>> +
>> +	return supported_fmts;
>> +}
>> +
>>  static int atmel_hlcdc_crtc_select_output_mode(struct drm_crtc_state *state)
>>  {
>>  	unsigned int output_fmts = ATMEL_HLCDC_OUTPUT_MODE_MASK;
>> @@ -238,31 +287,12 @@ static int atmel_hlcdc_crtc_select_output_mode(struct drm_crtc_state *state)
>>  	crtc = drm_crtc_to_atmel_hlcdc_crtc(state->crtc);
>>
>>  	for_each_new_connector_in_state(state->state, connector, cstate, i) {
>> -		struct drm_display_info *info = &connector->display_info;
>>  		unsigned int supported_fmts = 0;
>> -		int j;
>>
>>  		if (!cstate->crtc)
>>  			continue;
>>
>> -		for (j = 0; j < info->num_bus_formats; j++) {
>> -			switch (info->bus_formats[j]) {
>> -			case MEDIA_BUS_FMT_RGB444_1X12:
>> -				supported_fmts |= ATMEL_HLCDC_RGB444_OUTPUT;
>> -				break;
>> -			case MEDIA_BUS_FMT_RGB565_1X16:
>> -				supported_fmts |= ATMEL_HLCDC_RGB565_OUTPUT;
>> -				break;
>> -			case MEDIA_BUS_FMT_RGB666_1X18:
>> -				supported_fmts |= ATMEL_HLCDC_RGB666_OUTPUT;
>> -				break;
>> -			case MEDIA_BUS_FMT_RGB888_1X24:
>> -				supported_fmts |= ATMEL_HLCDC_RGB888_OUTPUT;
>> -				break;
>> -			default:
>> -				break;
>> -			}
>> -		}
>> +		supported_fmts = atmel_hlcdc_connector_output_mode(cstate);
>>
>>  		if (crtc->dc->desc->conflicting_output_formats)
>>  			output_fmts &= supported_fmts;
>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h
>> index 60c937f42114..4cc1e03f0aee 100644
>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h
>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h
>> @@ -441,5 +441,6 @@ void atmel_hlcdc_crtc_irq(struct drm_crtc *c);
>>  int atmel_hlcdc_crtc_create(struct drm_device *dev);
>>
>>  int atmel_hlcdc_create_outputs(struct drm_device *dev);
>> +int atmel_hlcdc_encoder_get_bus_fmt(struct drm_encoder *encoder);
>>
>>  #endif /* DRM_ATMEL_HLCDC_H */
>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
>> index 8db51fb131db..db4d6aaaef93 100644
>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
>> @@ -27,33 +27,86 @@
>>
>>  #include "atmel_hlcdc_dc.h"
>>
>> +struct atmel_hlcdc_rgb_output {
>> +	struct drm_encoder encoder;
>> +	int bus_fmt;
>> +};
>> +
>>  static const struct drm_encoder_funcs atmel_hlcdc_panel_encoder_funcs = {
>>  	.destroy = drm_encoder_cleanup,
>>  };
>>
>> +static struct atmel_hlcdc_rgb_output *
>> +atmel_hlcdc_encoder_to_rgb_output(struct drm_encoder *encoder)
>> +{
>> +	return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
>> +}
>> +
>> +int atmel_hlcdc_encoder_get_bus_fmt(struct drm_encoder *encoder)
> 
> 'static' missing?

No, it's also used from atmel_hlcdc_crtc.c

>> +{
>> +	struct atmel_hlcdc_rgb_output *output;
>> +
>> +	output = atmel_hlcdc_encoder_to_rgb_output(encoder);
>> +
>> +	return output->bus_fmt;
>> +}
>> +
>> +static int atmel_hlcdc_of_bus_fmt(struct device_node *ep)
>> +{
>> +	u32 bus_width = 0;
>> +
>> +	of_property_read_u32(ep, "bus-width", &bus_width);
>> +
>> +	switch (bus_width) {
>> +	case 0:
>> +		return 0;
>> +	case 12:
>> +		return MEDIA_BUS_FMT_RGB444_1X12;
>> +	case 16:
>> +		return MEDIA_BUS_FMT_RGB565_1X16;
>> +	case 18:
>> +		return MEDIA_BUS_FMT_RGB666_1X18;
>> +	case 24:
>> +		return MEDIA_BUS_FMT_RGB888_1X24;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>>  static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
>>  {
>> -	struct drm_encoder *encoder;
>> +	struct atmel_hlcdc_rgb_output *output;
>> +	struct device_node *ep;
>>  	struct drm_panel *panel;
>>  	struct drm_bridge *bridge;
>>  	int ret;
>>
>> +	ep = of_graph_get_endpoint_by_regs(dev->dev->of_node, 0, endpoint);
>> +	if (!ep)
>> +		return -ENODEV;
>> +
>>  	ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 0, endpoint,
>>  					  &panel, &bridge);
>>  	if (ret)
>>  		return ret;
>>
>> -	encoder = devm_kzalloc(dev->dev, sizeof(*encoder), GFP_KERNEL);
>> -	if (!encoder)
>> +	output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
>> +	if (!output)
>>  		return -EINVAL;
>>
>> -	ret = drm_encoder_init(dev, encoder,
>> +	output->bus_fmt = atmel_hlcdc_of_bus_fmt(ep);
>> +	if (output->bus_fmt < 0) {
>> +		dev_err(dev->dev, "invalid bus width\n");
> 
> Nit: Bindings do not specify 0 as an accepted value.

I'll add some error checks in atmel_hlcdc_of_bus_fmt...

Cheers,
Peter

> Feel free to add my
> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> with those two minors addressed.
> 
> Thanks
>    j
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = drm_encoder_init(dev, &output->encoder,
>>  			       &atmel_hlcdc_panel_encoder_funcs,
>>  			       DRM_MODE_ENCODER_NONE, NULL);
>>  	if (ret)
>>  		return ret;
>>
>> -	encoder->possible_crtcs = 0x1;
>> +	output->encoder.possible_crtcs = 0x1;
>>
>>  	if (panel) {
>>  		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_Unknown);
>> @@ -62,7 +115,7 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
>>  	}
>>
>>  	if (bridge) {
>> -		ret = drm_bridge_attach(encoder, bridge, NULL);
>> +		ret = drm_bridge_attach(&output->encoder, bridge, NULL);
>>  		if (!ret)
>>  			return 0;
>>
>> @@ -70,7 +123,7 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
>>  			drm_panel_bridge_remove(bridge);
>>  	}
>>
>> -	drm_encoder_cleanup(encoder);
>> +	drm_encoder_cleanup(&output->encoder);
>>
>>  	return ret;
>>  }
>> --
>> 2.11.0
>>