From patchwork Wed Jul 20 09:58:54 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Ripard X-Patchwork-Id: 9239315 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2F150600CB for ; Wed, 20 Jul 2016 10:03:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1D39B1FFD7 for ; Wed, 20 Jul 2016 10:03:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 118E52793D; Wed, 20 Jul 2016 10:03:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 789921FFD7 for ; Wed, 20 Jul 2016 10:03:20 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bPoK7-0007zj-3A; Wed, 20 Jul 2016 10:01:51 +0000 Received: from down.free-electrons.com ([37.187.137.238] helo=mail.free-electrons.com) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bPoHg-00052b-FO for linux-arm-kernel@lists.infradead.org; Wed, 20 Jul 2016 09:59:24 +0000 Received: by mail.free-electrons.com (Postfix, from userid 110) id 9D15D3F4; Wed, 20 Jul 2016 11:59:01 +0200 (CEST) Received: from localhost (LStLambert-657-1-97-87.w90-63.abo.wanadoo.fr [90.63.216.87]) by mail.free-electrons.com (Postfix) with ESMTPSA id 65884346; Wed, 20 Jul 2016 11:59:01 +0200 (CEST) From: Maxime Ripard To: Rob Herring , Daniel Vetter , David Airlie Subject: [PATCH v2 4/7] drm/bridge: Add RGB to VGA bridge support Date: Wed, 20 Jul 2016 11:58:54 +0200 Message-Id: <20160720095857.12297-5-maxime.ripard@free-electrons.com> X-Mailer: git-send-email 2.9.0 In-Reply-To: <20160720095857.12297-1-maxime.ripard@free-electrons.com> References: <20160720095857.12297-1-maxime.ripard@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160720_025921_067940_2519F796 X-CRM114-Status: GOOD ( 21.67 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Boris Brezillon , dri-devel@lists.freedesktop.org, Chen-Yu Tsai , Laurent Pinchart , Maxime Ripard , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Some boards have an entirely passive RGB to VGA bridge, based on either DACs or resistor ladders. Those might or might not have an i2c bus routed to the VGA connector in order to access the screen EDIDs. Add a bridge that doesn't do anything but expose the modes available on the screen, either based on the EDIDs if available, or based on the XGA standards. Signed-off-by: Maxime Ripard Acked-by: Rob Herring --- .../bindings/display/bridge/dumb-vga.txt | 54 +++++ drivers/gpu/drm/bridge/Kconfig | 6 + drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/dumb-vga.c | 232 +++++++++++++++++++++ 4 files changed, 293 insertions(+) create mode 100644 Documentation/devicetree/bindings/display/bridge/dumb-vga.txt create mode 100644 drivers/gpu/drm/bridge/dumb-vga.c diff --git a/Documentation/devicetree/bindings/display/bridge/dumb-vga.txt b/Documentation/devicetree/bindings/display/bridge/dumb-vga.txt new file mode 100644 index 000000000000..0056ffa2b31d --- /dev/null +++ b/Documentation/devicetree/bindings/display/bridge/dumb-vga.txt @@ -0,0 +1,54 @@ +Passive RGB to VGA bridge +------------------------- + +This binding is aimed for entirely passive RGB to VGA bridges that do not +require any configuration. + +Required properties: + +- compatible: Must be "dumb-vga-bridge" + +Required nodes: + +This device has two video ports. Their connections are modeled using the OF +graph bindings specified in Documentation/devicetree/bindings/graph.txt. + +- Video port 0 for RGB input +- Video port 1 for VGA output + + +Example +------- + +bridge { + compatible = "dumb-vga-bridge"; + #address-cells = <1>; + #size-cells = <0>; + + ports { + #address-cells = <1>; + #size-cells = <0>; + + port@0 { + #address-cells = <1>; + #size-cells = <0>; + reg = <0>; + + vga_bridge_in: endpoint@0 { + reg = <0>; + remote-endpoint = <&tcon0_out_vga>; + }; + }; + + port@1 { + #address-cells = <1>; + #size-cells = <0>; + reg = <1>; + + vga_bridge_out: endpoint@0 { + reg = <0>; + remote-endpoint = <&vga_con_in>; + }; + }; + }; +}; diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index a141921445f4..4a6560714397 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -17,6 +17,12 @@ config DRM_ANALOGIX_ANX78XX the HDMI output of an application processor to MyDP or DisplayPort. +config DRM_DUMB_VGA + tristate "Dumb RGB to VGA Bridge support" + select DRM_KMS_HELPER + help + Support for passive RGB to VGA bridges + config DRM_DW_HDMI tristate select DRM_KMS_HELPER diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index bfec9f8cb9d2..413d783828bb 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -1,6 +1,7 @@ ccflags-y := -Iinclude/drm obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o +obj-$(CONFIG_DRM_DUMB_VGA) += dumb-vga.o obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o diff --git a/drivers/gpu/drm/bridge/dumb-vga.c b/drivers/gpu/drm/bridge/dumb-vga.c new file mode 100644 index 000000000000..c197be591fb6 --- /dev/null +++ b/drivers/gpu/drm/bridge/dumb-vga.c @@ -0,0 +1,232 @@ + +#include +#include + +#include +#include +#include +#include + +struct dumb_vga { + struct drm_bridge bridge; + struct drm_connector connector; + + struct i2c_adapter *ddc; +}; + +static inline struct dumb_vga * +drm_bridge_to_dumb_vga(struct drm_bridge *bridge) +{ + return container_of(bridge, struct dumb_vga, bridge); +} + +static inline struct dumb_vga * +drm_connector_to_dumb_vga(struct drm_connector *connector) +{ + return container_of(connector, struct dumb_vga, connector); +} + +static int dumb_vga_get_modes(struct drm_connector *connector) +{ + struct dumb_vga *vga = drm_connector_to_dumb_vga(connector); + struct edid *edid; + int ret; + + if (IS_ERR(vga->ddc)) + goto fallback; + + edid = drm_get_edid(connector, vga->ddc); + if (!edid) { + DRM_INFO("EDID readout failed, falling back to standard modes\n"); + goto fallback; + } + + drm_mode_connector_update_edid_property(connector, edid); + return drm_add_edid_modes(connector, edid); + +fallback: + /* + * In case we cannot retrieve the EDIDs (broken or missing i2c + * bus), fallback on the XGA standards + */ + ret = drm_add_modes_noedid(connector, 1920, 1200); + + /* And prefer a mode pretty much anyone can handle */ + drm_set_preferred_mode(connector, 1024, 768); + + return ret; +} + +static struct drm_encoder * +dumb_vga_best_encoder(struct drm_connector *connector) +{ + struct dumb_vga *vga = drm_connector_to_dumb_vga(connector); + + return vga->bridge.encoder; +} + +static struct drm_connector_helper_funcs dumb_vga_con_helper_funcs = { + .get_modes = dumb_vga_get_modes, + .best_encoder = dumb_vga_best_encoder, +}; + +static enum drm_connector_status +dumb_vga_connector_detect(struct drm_connector *connector, bool force) +{ + struct dumb_vga *vga = drm_connector_to_dumb_vga(connector); + + /* + * Even if we have an I2C bus, we can't assume that the cable + * is disconnected if drm_probe_ddc. Some cables don't wire + * the DDC pins, or the I2C bus might be disfunctional. + */ + if (!IS_ERR(vga->ddc) && drm_probe_ddc(vga->ddc)) + return connector_status_connected; + + return connector_status_unknown; +} + +static void +dumb_vga_connector_destroy(struct drm_connector *connector) +{ + drm_connector_cleanup(connector); +} + +static struct drm_connector_funcs dumb_vga_con_funcs = { + .dpms = drm_atomic_helper_connector_dpms, + .detect = dumb_vga_connector_detect, + .fill_modes = drm_helper_probe_single_connector_modes, + .destroy = dumb_vga_connector_destroy, + .reset = drm_atomic_helper_connector_reset, + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, +}; + +static int dumb_vga_attach(struct drm_bridge *bridge) +{ + struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge); + int ret; + + if (!bridge->encoder) { + DRM_ERROR("Missing encoder\n"); + return -ENODEV; + } + + drm_connector_helper_add(&vga->connector, + &dumb_vga_con_helper_funcs); + ret = drm_connector_init(bridge->dev, &vga->connector, + &dumb_vga_con_funcs, DRM_MODE_CONNECTOR_VGA); + if (ret) { + DRM_ERROR("Failed to initialize connector\n"); + return ret; + } + + drm_mode_connector_attach_encoder(&vga->connector, + bridge->encoder); + + return 0; +} + +static void dumb_vga_nop(struct drm_bridge *bridge) {}; + +static struct drm_bridge_funcs dumb_vga_bridge_funcs = { + .attach = dumb_vga_attach, + .enable = dumb_vga_nop, + .disable = dumb_vga_nop, + .pre_enable = dumb_vga_nop, + .post_disable = dumb_vga_nop, +}; + +static struct i2c_adapter *dumb_vga_retrieve_ddc(struct device *dev) +{ + struct device_node *end_node, *phandle, *remote; + struct i2c_adapter *ddc; + + end_node = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1); + if (!end_node) { + dev_err(dev, "Missing connector endpoint\n"); + return ERR_PTR(-ENODEV); + } + + remote = of_graph_get_remote_port_parent(end_node); + of_node_put(end_node); + if (!remote) { + dev_err(dev, "Enable to parse remote node\n"); + return ERR_PTR(-EINVAL); + } + + phandle = of_parse_phandle(remote, "ddc-i2c-bus", 0); + of_node_put(remote); + if (!phandle) + return ERR_PTR(-ENODEV); + + ddc = of_get_i2c_adapter_by_node(phandle); + of_node_put(phandle); + if (!ddc) + return ERR_PTR(-EPROBE_DEFER); + + return ddc; +} + +static int dumb_vga_probe(struct platform_device *pdev) +{ + struct dumb_vga *vga; + int ret; + + vga = devm_kzalloc(&pdev->dev, sizeof(*vga), GFP_KERNEL); + if (!vga) + return -ENOMEM; + platform_set_drvdata(pdev, vga); + + vga->ddc = dumb_vga_retrieve_ddc(&pdev->dev); + if (IS_ERR(vga->ddc)) { + if (PTR_ERR(vga->ddc) == -ENODEV) { + dev_info(&pdev->dev, + "No i2c bus specified... Disabling EDID readout\n"); + } else { + dev_err(&pdev->dev, "Couldn't retrieve i2c bus\n"); + return PTR_ERR(vga->ddc); + } + } + + vga->bridge.funcs = &dumb_vga_bridge_funcs; + vga->bridge.of_node = pdev->dev.of_node; + + ret = drm_bridge_add(&vga->bridge); + if (ret && !IS_ERR(vga->ddc)) + i2c_put_adapter(vga->ddc); + + return ret; +} + +static int dumb_vga_remove(struct platform_device *pdev) +{ + struct dumb_vga *vga = platform_get_drvdata(pdev); + + drm_bridge_remove(&vga->bridge); + + if (!IS_ERR(vga->ddc)) + i2c_put_adapter(vga->ddc); + + return 0; +} + +static const struct of_device_id dumb_vga_match[] = { + { .compatible = "dumb-vga-bridge" }, + {}, +}; +MODULE_DEVICE_TABLE(of, dumb_vga_match); + +struct platform_driver dumb_vga_driver = { + .probe = dumb_vga_probe, + .remove = dumb_vga_remove, + .driver = { + .name = "dumb-vga-bridge", + .of_match_table = dumb_vga_match, + }, +}; +module_platform_driver(dumb_vga_driver); + +MODULE_AUTHOR("Maxime Ripard "); +MODULE_DESCRIPTION("Dumb RGB to VGA bridge driver"); +MODULE_LICENSE("GPL");