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

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Jyri,

On Thursday 17 Nov 2016 15:39:26 Jyri Sarha wrote:
> On 11/17/16 15:28, Jyri Sarha wrote:
> > Add very basic ti-ftp410 DVI transmitter driver. The only feature
> > 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>
> > ---
> > 
> >  .../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
> > @@ -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;
> > +	}
> > +
> > +	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);
> 
> Oops, forgot to handle the return values. This is how I fixed it:
> static int __init tfp410_module_init(void)
> {
> 	int ret;
> 
> 	ret = i2c_add_driver(&tfp410_i2c_driver);
> 	if (ret)
> 		return ret;
> 
> 	ret = platform_driver_register(&tfp410_platform_driver);
> 	if (ret)
> 		i2c_del_driver(&tfp410_i2c_driver);
> 
> 	return ret;
> }

If registration of one of the two drivers fail, wouldn't it make sense to 
still continue (probably with an error message) to avoid breaking the other 
one ?

> > +
> > +	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");

-- 
Regards,

Laurent Pinchart

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel