Re: [v3,2/3] drm/bridge: Add ti-tfp410 DVI transmitter driver

On 11/18/16 07:00, Christopher Spinrath wrote:

Hi Jyri,

On 11/17/2016 02:28 PM, Jyri Sarha wrote:

...

Add very basic ti-ftp410 DVI transmitter driver. The only feature

s/ftp/tfp ?

My fingers just want type these three letter is that order, wonder why :).

...

separating this from a completely dummy bridge is the EDID read support trough DDC I2C. Even that functionality should be in a separate generic connector driver. However, because of missing DRM infrastructure support the connector is implemented within the bridge driver. Some tfp410 HW specific features may be added later if needed, because there is a set of registers behind i2c if it is connected.

This implementation is tested against my new tilcdc bridge support and it works with BeagleBone DVI-D Cape Rev A3. A DT binding document is also added.

Signed-off-by: Jyri Sarha jsarha@ti.com

Thanks for working on this. I have tested the driver on my Utilite Pro which is based on the imx6q SoC and has a tfp410 chip hooked up to its parallel rgb24 interface. So you can add my

Tested-By: Christopher Spinrath christopher.spinrath@rwth-aachen.de

Thanks, I'll address these comments and resend the corrected patches before sending a pull request.

However, I have two more comments below.

...

---

.../bindings/display/bridge/ti,tfp410.txt | 40 +++ drivers/gpu/drm/bridge/Kconfig | 7 + drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/ti-tfp410.c | 287 +++++++++++++++++++++ 4 files changed, 335 insertions(+) create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,tfp410.txt create mode 100644 drivers/gpu/drm/bridge/ti-tfp410.c

diff --git a/Documentation/devicetree/bindings/display/bridge/ti,tfp410.txt b/Documentation/devicetree/bindings/display/bridge/ti,tfp410.txt new file mode 100644 index 0000000..6174b18 --- /dev/null +++ b/Documentation/devicetree/bindings/display/bridge/ti,tfp410.txt

There already is a binding documentation for the tfp410 in

Documentation/devicetree/bindings/display/ti/ti,tfp410.txt .

It is used by the omap drm driver. IMHO you should extend, move or deprecate that one. Note that it describes an optional powerdown-gpios property.

Good that you noticed that. Guess we need to unify those. Probably to the new location under bridge directory.

...

@@ -0,0 +1,40 @@ +TFP410 DVI bridge bindings

+Required properties:

• • compatible: "ti,tfp410"

+Optional properties

• • reg: I2C address. If and only if present the device node

•  should be placed into the i2c controller node where the
  

•  tfp410 i2c is connected to.
  

+Required subnodes:

• • port@0: Video input port node to connect the bridge to a

•  display controller output [1].
  

• • port@1: Video output port node to connect the bridge to a

•  connector input [1].
  

+[1]: Documentation/devicetree/bindings/media/video-interfaces.txt

+Example:

• hdmi-bridge {

• compatible = "ti,tfp410";
  

• ports {
  

• 	#address-cells = <1>;
  

• 	#size-cells = <0>;
  

• 	port@0 {
  

• 		reg = <0>;
  

• 		bridge_in: endpoint {
  

• 			remote-endpoint = <&dc_out>;
  

• 		};
  

• 	};
  

• 	port@1 {
  

• 		reg = <1>;
  

• 		bridge_out: endpoint {
  

• 			remote-endpoint = <&hdmi_in>;
  

• 		};
  

• 	};
  

• };
  

• };

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index bd6acc8..a424e03 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -81,6 +81,13 @@ config DRM_TOSHIBA_TC358767 ---help--- Toshiba TC358767 eDP bridge chip driver.

+config DRM_TI_TFP410

• tristate "TI TFP410 DVI/HDMI bridge"
• depends on OF
• select DRM_KMS_HELPER
• ---help---

•  Texas Instruments TFP410 DVI/HDMI Transmitter driver
  

source "drivers/gpu/drm/bridge/analogix/Kconfig"

source "drivers/gpu/drm/bridge/adv7511/Kconfig" diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index 97ed1a5..8b065d9 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_DRM_SII902X) += sii902x.o obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/ obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/ +obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o diff --git a/drivers/gpu/drm/bridge/ti-tfp410.c b/drivers/gpu/drm/bridge/ti-tfp410.c new file mode 100644 index 0000000..64f54e4 --- /dev/null +++ b/drivers/gpu/drm/bridge/ti-tfp410.c @@ -0,0 +1,287 @@ +/*

• • Copyright (C) 2016 Texas Instruments
• • Author: Jyri Sarha jsarha@ti.com
• • This program is free software; you can redistribute it and/or modify it
• • under the terms of the GNU General Public License version 2 as published by
• • the Free Software Foundation.
• */

+#include <linux/module.h> +#include <linux/of_graph.h> +#include <linux/platform_device.h> +#include <linux/i2c.h>

+#include <drm/drmP.h> +#include <drm/drm_atomic_helper.h> +#include <drm/drm_crtc.h> +#include <drm/drm_crtc_helper.h>

+struct tfp410 {

• struct drm_bridge bridge;
• struct drm_connector connector;
• struct i2c_adapter *ddc;
• struct device *dev;

+};

+static inline struct tfp410 * +drm_bridge_to_tfp410(struct drm_bridge *bridge) +{

• return container_of(bridge, struct tfp410, bridge);

+}

+static inline struct tfp410 * +drm_connector_to_tfp410(struct drm_connector *connector) +{

• return container_of(connector, struct tfp410, connector);

+}

+static int tfp410_get_modes(struct drm_connector *connector) +{

• struct tfp410 *dvi = drm_connector_to_tfp410(connector);
• struct edid *edid;
• int ret;
• if (!dvi->ddc)

• goto fallback;
  

• edid = drm_get_edid(connector, dvi->ddc);
• if (!edid) {

• DRM_INFO("EDID read failed. Fallback to standard modes\n");
  

• goto fallback;
  

• }
• drm_mode_connector_update_edid_property(connector, edid);
• return drm_add_edid_modes(connector, edid);

+fallback:

• /* No EDID, fallback on the XGA standard modes */
• ret = drm_add_modes_noedid(connector, 1920, 1200);
• /* And prefer a mode pretty much anything can handle */
• drm_set_preferred_mode(connector, 1024, 768);
• return ret;

+}

+static const struct drm_connector_helper_funcs tfp410_con_helper_funcs = {

• .get_modes = tfp410_get_modes,

+};

+static enum drm_connector_status +tfp410_connector_detect(struct drm_connector *connector, bool force) +{

• struct tfp410 *dvi = drm_connector_to_tfp410(connector);
• if (dvi->ddc) {

• if (drm_probe_ddc(dvi->ddc))
  

• 	return connector_status_connected;
  

• else
  

• 	return connector_status_disconnected;
  

• }

I wonder what happens if a display with none or defect ddc/edid is attached? The dumb-vga-dac bridge driver reports connector_status_unknown in the case drm_probe_ddc fails.

If there is such a problem with DVI/HDMI device, then the device is clearly broken. In such a case one can hack a custom dtd file without ddc-i2c-bus. The situation with VGA is slightly different. There may still be some perfectly legitimate legacy VGA devices that do not support ddc.

I do not have a strong opinion about this, but would like to wait if anybody is bothered about this behaviour and fix it only if there is a problem.

Cheers, Christopher

...

• return connector_status_unknown;

+}

+static const struct drm_connector_funcs tfp410_con_funcs = {

• .dpms = drm_atomic_helper_connector_dpms,
• .detect = tfp410_connector_detect,
• .fill_modes = drm_helper_probe_single_connector_modes,
• .destroy = drm_connector_cleanup,
• .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 tfp410_attach(struct drm_bridge *bridge) +{

• struct tfp410 *dvi = drm_bridge_to_tfp410(bridge);
• int ret;
• if (!bridge->encoder) {

• dev_err(dvi->dev, "Missing encoder\n");
  

• return -ENODEV;
  

• }
• drm_connector_helper_add(&dvi->connector,

• 		 &tfp410_con_helper_funcs);
  

• ret = drm_connector_init(bridge->dev, &dvi->connector,

• 		 &tfp410_con_funcs, DRM_MODE_CONNECTOR_HDMIA);
  

• if (ret) {

• dev_err(dvi->dev, "drm_connector_init() failed: %d\n", ret);
  

• return ret;
  

• }
• drm_mode_connector_attach_encoder(&dvi->connector,

• 			  bridge->encoder);
  

• return 0;

+}

+static const struct drm_bridge_funcs tfp410_bridge_funcs = {

• .attach = tfp410_attach,

+};

+static int tfp410_get_connector_ddc(struct tfp410 *dvi) +{

• struct device_node *ep = NULL, *connector_node = NULL;
• struct device_node *ddc_phandle = NULL;
• int ret = 0;
• /* port@1 is the connector node */
• ep = of_graph_get_endpoint_by_regs(dvi->dev->of_node, 1, -1);
• if (!ep)

• goto fail;
  

• connector_node = of_graph_get_remote_port_parent(ep);
• if (!connector_node)

• goto fail;
  

• ddc_phandle = of_parse_phandle(connector_node, "ddc-i2c-bus", 0);
• if (!ddc_phandle)

• goto fail;
  

• dvi->ddc = of_get_i2c_adapter_by_node(ddc_phandle);
• if (dvi->ddc)

• dev_info(dvi->dev, "Connector's ddc i2c bus found\n");
  

• else

• ret = -EPROBE_DEFER;
  

+fail:

• of_node_put(ep);
• of_node_put(connector_node);
• of_node_put(ddc_phandle);
• return ret;

+}

+static int tfp410_init(struct device *dev) +{

• struct tfp410 *dvi;
• int ret;
• if (!dev->of_node) {

• dev_err(dev, "device-tree data is missing\n");
  

• return -ENXIO;
  

• }
• dvi = devm_kzalloc(dev, sizeof(*dvi), GFP_KERNEL);
• if (!dvi)

• return -ENOMEM;
  

• dev_set_drvdata(dev, dvi);
• dvi->bridge.funcs = &tfp410_bridge_funcs;
• dvi->bridge.of_node = dev->of_node;
• dvi->dev = dev;
• ret = tfp410_get_connector_ddc(dvi);
• if (ret)

• goto fail;
  

• ret = drm_bridge_add(&dvi->bridge);
• if (ret) {

• dev_err(dev, "drm_bridge_add() failed: %d\n", ret);
  

• goto fail;
  

• }
• return 0;

+fail:

• i2c_put_adapter(dvi->ddc);
• return ret;

+}

+static int tfp410_fini(struct device *dev) +{

• struct tfp410 *dvi = dev_get_drvdata(dev);
• drm_bridge_remove(&dvi->bridge);
• if (dvi->ddc)

• i2c_put_adapter(dvi->ddc);
  

• return 0;

+}

+static int tfp410_probe(struct platform_device *pdev) +{

• return tfp410_init(&pdev->dev);

+}

+static int tfp410_remove(struct platform_device *pdev) +{

• return tfp410_fini(&pdev->dev);

+}

+/* There is currently no i2c functionality. */ +static int tfp410_i2c_probe(struct i2c_client *client,

• 	    const struct i2c_device_id *id)
  

+{

• int reg;
• if (!client->dev.of_node ||

•    of_property_read_u32(client->dev.of_node, "reg", &reg)) {
  

• dev_err(&client->dev,
  

• 	"Can't get i2c reg property from device-tree\n");
  

• return -ENXIO;
  

• }
• return tfp410_init(&client->dev);

+}

+static int tfp410_i2c_remove(struct i2c_client *client) +{

• return tfp410_fini(&client->dev);

+}

+static const struct of_device_id tfp410_match[] = {

• { .compatible = "ti,tfp410" },
• {},

+}; +MODULE_DEVICE_TABLE(of, tfp410_match);

+struct platform_driver tfp410_platform_driver = {

• .probe = tfp410_probe,
• .remove = tfp410_remove,
• .driver = {

• .name		= "tfp410-bridge",
  

• .of_match_table	= tfp410_match,
  

• },

+};

+static const struct i2c_device_id tfp410_i2c_ids[] = {

• { "tfp410", 0 },
• { }

+}; +MODULE_DEVICE_TABLE(i2c, tfp410_i2c_ids);

+static struct i2c_driver tfp410_i2c_driver = {

• .driver = {

• .name	= "tfp410",
  

• .of_match_table = of_match_ptr(tfp410_match),
  

• },
• .id_table = tfp410_i2c_ids,
• .probe = tfp410_i2c_probe,
• .remove = tfp410_i2c_remove,

+};

+static int __init tfp410_module_init(void) +{

• i2c_add_driver(&tfp410_i2c_driver);
• platform_driver_register(&tfp410_platform_driver);
• return 0;

+} +module_init(tfp410_module_init);

+static void __exit tfp410_module_exit(void) +{

• i2c_del_driver(&tfp410_i2c_driver);
• platform_driver_unregister(&tfp410_platform_driver);

+} +module_exit(tfp410_module_exit);

+MODULE_AUTHOR("Jyri Sarha jsarha@ti.com"); +MODULE_DESCRIPTION("TI TFP410 DVI bridge driver"); +MODULE_LICENSE("GPL");