Hi Jacopo,
Thank you for your feedback!
> From: Jacopo Mondi <jacopo@xxxxxxxxxx>
> Sent: 07 November 2019 18:19
> Subject: Re: [PATCH v2 1/4] drm/bridge: Repurpose lvds-encoder.c
>
> Hi Fabrizio,
> thanks for the patch.
>
> On Mon, Nov 04, 2019 at 04:58:00PM +0000, Fabrizio Castro wrote:
> > lvds-encoder.c implementation is also suitable for LVDS decoders,
> > not just LVDS encoders.
> > Instead of creating a new driver for addressing support for
> > transparent LVDS decoders, repurpose lvds-encoder.c for the greater
> > good.
> >
> > Signed-off-by: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx>
> >
> > ---
> > v1->v2:
> > * No change
> > ---
> > drivers/gpu/drm/bridge/Kconfig | 8 +-
> > drivers/gpu/drm/bridge/Makefile | 2 +-
> > drivers/gpu/drm/bridge/lvds-codec.c | 169 ++++++++++++++++++++++++++++++++++
> > drivers/gpu/drm/bridge/lvds-encoder.c | 155 -------------------------------
> > 4 files changed, 174 insertions(+), 160 deletions(-)
> > create mode 100644 drivers/gpu/drm/bridge/lvds-codec.c
> > delete mode 100644 drivers/gpu/drm/bridge/lvds-encoder.c
> >
> > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> > index 3436297..9e75ca4e 100644
> > --- a/drivers/gpu/drm/bridge/Kconfig
> > +++ b/drivers/gpu/drm/bridge/Kconfig
> > @@ -45,14 +45,14 @@ config DRM_DUMB_VGA_DAC
> > Support for non-programmable RGB to VGA DAC bridges, such as ADI
> > ADV7123, TI THS8134 and THS8135 or passive resistor ladder DACs.
> >
> > -config DRM_LVDS_ENCODER
> > - tristate "Transparent parallel to LVDS encoder support"
> > +config DRM_LVDS_CODEC
> > + tristate "Transparent LVDS encoders and decoders support"
> > depends on OF
> > select DRM_KMS_HELPER
> > select DRM_PANEL_BRIDGE
> > help
> > - Support for transparent parallel to LVDS encoders that don't require
> > - any configuration.
> > + Support for transparent LVDS encoders and LVDS decoders that don't
> > + require any configuration.
> >
> > config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
> > tristate "MegaChips stdp4028-ge-b850v3-fw and stdp2690-ge-b850v3-fw"
> > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> > index 4934fcf..8a9178a 100644
> > --- a/drivers/gpu/drm/bridge/Makefile
> > +++ b/drivers/gpu/drm/bridge/Makefile
> > @@ -2,7 +2,7 @@
> > obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
> > obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
> > obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
> > -obj-$(CONFIG_DRM_LVDS_ENCODER) += lvds-encoder.o
> > +obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
> > obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
> > obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
> > obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
> > diff --git a/drivers/gpu/drm/bridge/lvds-codec.c b/drivers/gpu/drm/bridge/lvds-codec.c
> > new file mode 100644
> > index 0000000..8a1979c
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/lvds-codec.c
> > @@ -0,0 +1,169 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > + */
> > +
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_graph.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include <drm/drm_bridge.h>
> > +#include <drm/drm_panel.h>
> > +
> > +struct lvds_codec {
> > + struct drm_bridge bridge;
> > + struct drm_bridge *panel_bridge;
> > + struct gpio_desc *powerdown_gpio;
> > + u32 connector_type;
> > +};
> > +
> > +static int lvds_codec_attach(struct drm_bridge *bridge)
> > +{
> > + struct lvds_codec *lvds_codec = container_of(bridge,
> > + struct lvds_codec,
> > + bridge);
> > +
>
> Weird indentation. Align to open ( to match the rest of the driver's
> style.
Will do, throughout the file.
>
> > + return drm_bridge_attach(bridge->encoder, lvds_codec->panel_bridge,
> > + bridge);
> > +}
> > +
> > +static void lvds_codec_enable(struct drm_bridge *bridge)
> > +{
> > + struct lvds_codec *lvds_codec = container_of(bridge,
> > + struct lvds_codec,
> > + bridge);
> > +
>
> Here too
>
> > + if (lvds_codec->powerdown_gpio)
> > + gpiod_set_value_cansleep(lvds_codec->powerdown_gpio, 0);
> > +}
> > +
> > +static void lvds_codec_disable(struct drm_bridge *bridge)
> > +{
> > + struct lvds_codec *lvds_codec = container_of(bridge,
> > + struct lvds_codec,
> > + bridge);
> > +
> > + if (lvds_codec->powerdown_gpio)
> > + gpiod_set_value_cansleep(lvds_codec->powerdown_gpio, 1);
> > +}
> > +
> > +static struct drm_bridge_funcs funcs = {
> > + .attach = lvds_codec_attach,
> > + .enable = lvds_codec_enable,
> > + .disable = lvds_codec_disable,
> > +};
> > +
> > +static int lvds_codec_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct device_node *port;
> > + struct device_node *endpoint;
> > + struct device_node *panel_node;
> > + struct drm_panel *panel;
> > + struct lvds_codec *lvds_codec;
> > +
> > + lvds_codec = devm_kzalloc(dev, sizeof(*lvds_codec), GFP_KERNEL);
> > + if (!lvds_codec)
> > + return -ENOMEM;
> > +
> > + lvds_codec->connector_type = (u32)
> > + of_device_get_match_data(&pdev->dev);
>
> Fits in 1 line
Will take it out
>
> > + lvds_codec->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
> > + GPIOD_OUT_HIGH);
> > + if (IS_ERR(lvds_codec->powerdown_gpio)) {
> > + int err = PTR_ERR(lvds_codec->powerdown_gpio);
> > +
> > + if (err != -EPROBE_DEFER)
> > + dev_err(dev, "powerdown GPIO failure: %d\n", err);
> > + return err;
>
> I know it was there already, but this seems a bit unusual for the
> minimal gain of having a printout in the very unlikely case the
> gpiod_get() operations fails. I would just return PTR_ERR().
Will change
>
> > + }
> > +
> > + /* Locate the panel DT node. */
> > + port = of_graph_get_port_by_id(dev->of_node, 1);
> > + if (!port) {
> > + dev_dbg(dev, "port 1 not found\n");
> > + return -ENXIO;
> > + }
> > +
> > + endpoint = of_get_child_by_name(port, "endpoint");
> > + of_node_put(port);
> > + if (!endpoint) {
> > + dev_dbg(dev, "no endpoint for port 1\n");
> > + return -ENXIO;
> > + }
>
> I know it was there already, but this could be simplified with
> of_graph_get_endpoint_by_regs()
> > +
> > + panel_node = of_graph_get_remote_port_parent(endpoint);
> > + of_node_put(endpoint);
> > + if (!panel_node) {
> > + dev_dbg(dev, "no remote endpoint for port 1\n");
> > + return -ENXIO;
> > + }
>
> Or even better, simplify these three with of_graph_get_remote_node()
Good catch, of_graph_get_remote_node seems the best approach,
I will go with that
>
> > +
> > + panel = of_drm_find_panel(panel_node);
> > + of_node_put(panel_node);
> > + if (IS_ERR(panel)) {
> > + dev_dbg(dev, "panel not found, deferring probe\n");
> > + return PTR_ERR(panel);
> > + }
> > +
> > + lvds_codec->panel_bridge =
> > + devm_drm_panel_bridge_add_typed(dev, panel,
> > + lvds_codec->connector_type);
>
> The function documentation reports this as deprecated and suggested to
> use the non-typed version. Do you think it could work for this new
> codec driver ?
I think so. However, the panel I am using doesn't define the connector type,
probably because none of the DRM_MODE_CONNECTOR_* seem to fit
perfectly, therefore I am probably going to need to define
DRM_MODE_CONNECTOR_PARALLEL.
I'll send v3 shortly so that you can have a look at what I mean, please advise
on the best course of action.
>
> > + if (IS_ERR(lvds_codec->panel_bridge))
> > + return PTR_ERR(lvds_codec->panel_bridge);
> > +
> > + /* The panel_bridge bridge is attached to the panel's of_node,
> > + * but we need a bridge attached to our of_node for our user
> > + * to look up.
> > + */
> > + lvds_codec->bridge.of_node = dev->of_node;
> > + lvds_codec->bridge.funcs = &funcs;
> > + drm_bridge_add(&lvds_codec->bridge);
> > +
> > + platform_set_drvdata(pdev, lvds_codec);
> > +
> > + return 0;
> > +}
> > +
> > +static int lvds_codec_remove(struct platform_device *pdev)
> > +{
> > + struct lvds_codec *lvds_codec = platform_get_drvdata(pdev);
> > +
> > + drm_bridge_remove(&lvds_codec->bridge);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id lvds_codec_match[] = {
> > + {
> > + .compatible = "lvds-encoder",
> > + .data = (void *)DRM_MODE_CONNECTOR_LVDS
>
> In case you for for drm_panel_bridge_add() you could drop the type
Will do
>
> > + },
> > + {
> > + .compatible = "thine,thc63lvdm83d",
> > + .data = (void *)DRM_MODE_CONNECTOR_LVDS,
> > + },
> > + {
> > + .compatible = "lvds-decoder",
> > + .data = (void *)DRM_MODE_CONNECTOR_Unknown,
> > + },
>
> Which decoder are you using? This is a generic fallback, but I would
> expect compatible for a real device to appear in DTS.
I am using the DS90CF384AMTDX/NOPB.
This driver is for transparent encoders and decoders, which means
there is no way you can control them. I don't think we should add
any device specific compatible string here, as it would be of no use.
The original dt-bindings for the encoders requires a device specific
compatible string for encoders with additional properties, I think
we should keep it that way for decoders too. I am not going to
use a device specific compatible string in the DT either for the
time being, unless really necessary.
I will send a v3 shortly. Thank you for your help so far!
Fab
>
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(of, lvds_codec_match);
> > +
> > +static struct platform_driver lvds_codec_driver = {
> > + .probe = lvds_codec_probe,
> > + .remove = lvds_codec_remove,
> > + .driver = {
> > + .name = "lvds-codec",
> > + .of_match_table = lvds_codec_match,
> > + },
> > +};
> > +module_platform_driver(lvds_codec_driver);
> > +
> > +MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("Driver for transparent LVDS encoders and LVDS decoders");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/gpu/drm/bridge/lvds-encoder.c b/drivers/gpu/drm/bridge/lvds-encoder.c
> > deleted file mode 100644
> > index e2132a8..0000000
> > --- a/drivers/gpu/drm/bridge/lvds-encoder.c
> > +++ /dev/null
> > @@ -1,155 +0,0 @@
> > -// SPDX-License-Identifier: GPL-2.0-or-later
> > -/*
> > - * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > - */
> > -
> > -#include <linux/gpio/consumer.h>
> > -#include <linux/module.h>
> > -#include <linux/of.h>
> > -#include <linux/of_graph.h>
> > -#include <linux/platform_device.h>
> > -
> > -#include <drm/drm_bridge.h>
> > -#include <drm/drm_panel.h>
> > -
> > -struct lvds_encoder {
> > - struct drm_bridge bridge;
> > - struct drm_bridge *panel_bridge;
> > - struct gpio_desc *powerdown_gpio;
> > -};
> > -
> > -static int lvds_encoder_attach(struct drm_bridge *bridge)
> > -{
> > - struct lvds_encoder *lvds_encoder = container_of(bridge,
> > - struct lvds_encoder,
> > - bridge);
> > -
> > - return drm_bridge_attach(bridge->encoder, lvds_encoder->panel_bridge,
> > - bridge);
> > -}
> > -
> > -static void lvds_encoder_enable(struct drm_bridge *bridge)
> > -{
> > - struct lvds_encoder *lvds_encoder = container_of(bridge,
> > - struct lvds_encoder,
> > - bridge);
> > -
> > - if (lvds_encoder->powerdown_gpio)
> > - gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 0);
> > -}
> > -
> > -static void lvds_encoder_disable(struct drm_bridge *bridge)
> > -{
> > - struct lvds_encoder *lvds_encoder = container_of(bridge,
> > - struct lvds_encoder,
> > - bridge);
> > -
> > - if (lvds_encoder->powerdown_gpio)
> > - gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 1);
> > -}
> > -
> > -static struct drm_bridge_funcs funcs = {
> > - .attach = lvds_encoder_attach,
> > - .enable = lvds_encoder_enable,
> > - .disable = lvds_encoder_disable,
> > -};
> > -
> > -static int lvds_encoder_probe(struct platform_device *pdev)
> > -{
> > - struct device *dev = &pdev->dev;
> > - struct device_node *port;
> > - struct device_node *endpoint;
> > - struct device_node *panel_node;
> > - struct drm_panel *panel;
> > - struct lvds_encoder *lvds_encoder;
> > -
> > - lvds_encoder = devm_kzalloc(dev, sizeof(*lvds_encoder), GFP_KERNEL);
> > - if (!lvds_encoder)
> > - return -ENOMEM;
> > -
> > - lvds_encoder->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
> > - GPIOD_OUT_HIGH);
> > - if (IS_ERR(lvds_encoder->powerdown_gpio)) {
> > - int err = PTR_ERR(lvds_encoder->powerdown_gpio);
> > -
> > - if (err != -EPROBE_DEFER)
> > - dev_err(dev, "powerdown GPIO failure: %d\n", err);
> > - return err;
> > - }
> > -
> > - /* Locate the panel DT node. */
> > - port = of_graph_get_port_by_id(dev->of_node, 1);
> > - if (!port) {
> > - dev_dbg(dev, "port 1 not found\n");
> > - return -ENXIO;
> > - }
> > -
> > - endpoint = of_get_child_by_name(port, "endpoint");
> > - of_node_put(port);
> > - if (!endpoint) {
> > - dev_dbg(dev, "no endpoint for port 1\n");
> > - return -ENXIO;
> > - }
> > -
> > - panel_node = of_graph_get_remote_port_parent(endpoint);
> > - of_node_put(endpoint);
> > - if (!panel_node) {
> > - dev_dbg(dev, "no remote endpoint for port 1\n");
> > - return -ENXIO;
> > - }
> > -
> > - panel = of_drm_find_panel(panel_node);
> > - of_node_put(panel_node);
> > - if (IS_ERR(panel)) {
> > - dev_dbg(dev, "panel not found, deferring probe\n");
> > - return PTR_ERR(panel);
> > - }
> > -
> > - lvds_encoder->panel_bridge =
> > - devm_drm_panel_bridge_add_typed(dev, panel,
> > - DRM_MODE_CONNECTOR_LVDS);
> > - if (IS_ERR(lvds_encoder->panel_bridge))
> > - return PTR_ERR(lvds_encoder->panel_bridge);
> > -
> > - /* The panel_bridge bridge is attached to the panel's of_node,
> > - * but we need a bridge attached to our of_node for our user
> > - * to look up.
> > - */
> > - lvds_encoder->bridge.of_node = dev->of_node;
> > - lvds_encoder->bridge.funcs = &funcs;
> > - drm_bridge_add(&lvds_encoder->bridge);
> > -
> > - platform_set_drvdata(pdev, lvds_encoder);
> > -
> > - return 0;
> > -}
> > -
> > -static int lvds_encoder_remove(struct platform_device *pdev)
> > -{
> > - struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
> > -
> > - drm_bridge_remove(&lvds_encoder->bridge);
> > -
> > - return 0;
> > -}
> > -
> > -static const struct of_device_id lvds_encoder_match[] = {
> > - { .compatible = "lvds-encoder" },
> > - { .compatible = "thine,thc63lvdm83d" },
> > - {},
> > -};
> > -MODULE_DEVICE_TABLE(of, lvds_encoder_match);
> > -
> > -static struct platform_driver lvds_encoder_driver = {
> > - .probe = lvds_encoder_probe,
> > - .remove = lvds_encoder_remove,
> > - .driver = {
> > - .name = "lvds-encoder",
> > - .of_match_table = lvds_encoder_match,
> > - },
> > -};
> > -module_platform_driver(lvds_encoder_driver);
> > -
> > -MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>");
> > -MODULE_DESCRIPTION("Transparent parallel to LVDS encoder");
> > -MODULE_LICENSE("GPL");
> > --
> > 2.7.4
> >
