[PATCH v2 11/50] drm/bridge: Add bridge driver for display connectors

[Boris Brezillon]

On Tue, 20 Aug 2019 04:16:42 +0300
Laurent Pinchart <laurent.pinchart at ideasonboard.com> wrote:

> +	/*
> +	 * Get the HPD GPIO for DVI and HDMI connectors. If the GPIO can provide
> +	 * interrupts, register an interrupt handler.
> +	 */
> +	if (type == DRM_MODE_CONNECTOR_DVII ||
> +	    type == DRM_MODE_CONNECTOR_HDMIA) {
> +		conn->hpd_gpio = devm_gpiod_get_optional(&pdev->dev, "hpd",
> +							 GPIOD_IN);
> +		if (IS_ERR(conn->hpd_gpio)) {
> +			if (PTR_ERR(conn->hpd_gpio) != -EPROBE_DEFER)
> +				dev_err(&pdev->dev,
> +					"Unable to retrieve HPD GPIO\n");
> +			return PTR_ERR(conn->hpd_gpio);
> +		}
> +
> +		conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
> +	} else {
> +		conn->hpd_irq = -EINVAL;
> +	}
> +
> +	if (conn->hpd_irq >= 0) {
> +		ret = devm_request_threaded_irq(&pdev->dev, conn->hpd_irq,
> +						NULL, display_connector_hpd_irq,
> +						IRQF_TRIGGER_RISING |
> +						IRQF_TRIGGER_FALLING |
> +						IRQF_ONESHOT,
> +						"HPD", conn);
> +		if (ret) {
> +			dev_err(&pdev->dev,
> +				"Failed to request HPD interrupt\n");
> +			return ret;

Is there anything that mandates support of edge events on GPIO chips?
I know it's quite common, but maybe we should fallback to polling
mode when devm_request_threaded_irq() fails.

> +		}
> +	}
> +
> +	/* Retrieve the DDC I2C adapter for DVI, HDMI and VGA connectors. */
> +	if (type == DRM_MODE_CONNECTOR_DVII ||
> +	    type == DRM_MODE_CONNECTOR_HDMIA ||
> +	    type == DRM_MODE_CONNECTOR_VGA) {
> +		struct device_node *phandle;
> +
> +		phandle = of_parse_phandle(pdev->dev.of_node, "ddc-i2c-bus", 0);
> +		if (phandle) {
> +			conn->bridge.ddc = of_get_i2c_adapter_by_node(phandle);
> +			of_node_put(phandle);
> +			if (!conn->bridge.ddc)
> +				return -EPROBE_DEFER;
> +		} else {
> +			dev_dbg(&pdev->dev,
> +				"No I2C bus specified, disabling EDID readout\n");
> +		}
> +	}
> +