Re: [PATCH v1 2/2] drm:bridge: Add Lontiun LT7911EXC eDP to MIPI DSI bridge

[Dmitry Baryshkov]

On Tue, Apr 28, 2026 at 04:12:40PM +0800, 杨孙运 wrote:
> Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx> 于2026年4月28日周二 15:49写道：
> >
> > On Tue, Apr 28, 2026 at 02:32:24PM +0800, syyang@xxxxxxxxxxx wrote:
> > > From: Sunyun Yang <syyang@xxxxxxxxxxx>
> > >
> > > The LT7911EXC is an I2C-controlled bridge that Receiver eDP1.4
> > > and output signal/dual port mipi.
> > >
> > > Signed-off-by: Sunyun Yang <syyang@xxxxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/bridge/Kconfig             |  13 +
> > >  drivers/gpu/drm/bridge/Makefile            |   1 +
> > >  drivers/gpu/drm/bridge/lontium-lt7911exc.c | 497 +++++++++++++++++++++
> > >  3 files changed, 511 insertions(+)
> > >  create mode 100644 drivers/gpu/drm/bridge/lontium-lt7911exc.c
> > >
> > > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> > > index c3209b0f4678..8cff2bf15b09 100644
> > > --- a/drivers/gpu/drm/bridge/Kconfig
> > > +++ b/drivers/gpu/drm/bridge/Kconfig
> > > @@ -132,6 +132,19 @@ config DRM_ITE_IT6505
> > >       help
> > >         ITE IT6505 DisplayPort bridge chip driver.
> > >
> > > +config DRM_LONTIUM_LT7911EXC
> > > +     tristate "Lontium eDP/MIPI bridge"
> > > +     depends on OF
> > > +     select CRC32
> > > +     select FW_LOADER
> > > +     select DRM_PANEL
> > > +     select DRM_KMS_HELPER
> > > +     help
> > > +       DRM driver for the Lontium LT7911EXC bridge chip.
> > > +       The LT7911EXC converts eDP input to single/dual port
> > > +       MIPI DSI output.
> > > +       Please say Y if you have such hardware.
> > > +
> > >  config DRM_LONTIUM_LT8912B
> > >       tristate "Lontium LT8912B DSI/HDMI bridge"
> > >       depends on OF
> > > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> > > index beab5b695a6e..70ddca75dd3a 100644
> > > --- a/drivers/gpu/drm/bridge/Makefile
> > > +++ b/drivers/gpu/drm/bridge/Makefile
> > > @@ -13,6 +13,7 @@ obj-$(CONFIG_DRM_I2C_NXP_TDA998X) += tda998x.o
> > >  obj-$(CONFIG_DRM_INNO_HDMI) += inno-hdmi.o
> > >  obj-$(CONFIG_DRM_ITE_IT6263) += ite-it6263.o
> > >  obj-$(CONFIG_DRM_ITE_IT6505) += ite-it6505.o
> > > +obj-$(CONFIG_DRM_LONTIUM_LT7911EXC) += lontium-lt7911exc.o
> > >  obj-$(CONFIG_DRM_LONTIUM_LT8912B) += lontium-lt8912b.o
> > >  obj-$(CONFIG_DRM_LONTIUM_LT9211) += lontium-lt9211.o
> > >  obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
> > > diff --git a/drivers/gpu/drm/bridge/lontium-lt7911exc.c b/drivers/gpu/drm/bridge/lontium-lt7911exc.c
> > > new file mode 100644
> > > index 000000000000..85cb6cedbfa3
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/bridge/lontium-lt7911exc.c
> > > @@ -0,0 +1,497 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (C) 2026 Lontium Semiconductor, Inc.
> > > + */
> > > +
> > > +#include <linux/crc32.h>
> > > +#include <linux/firmware.h>
> > > +#include <linux/gpio/consumer.h>
> > > +#include <linux/i2c.h>
> > > +#include <linux/module.h>
> > > +#include <linux/mutex.h>
> > > +#include <linux/of_graph.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include <drm/drm_bridge.h>
> > > +#include <drm/drm_mipi_dsi.h>
> > > +#include <drm/drm_of.h>
> > > +
> > > +#define FW_SIZE (64 * 1024)
> > > +#define LT_PAGE_SIZE 32
> > > +#define FW_FILE  "lt7911exc_fw.bin"
> >
> > Do you plan to submit the referene image to linux-firmware?
> >
> I want to submit it, but I don't know how. Please help me.

Read the README in that repo.

> 
> > > +#define LT7911EXC_PAGE_CONTROL 0xff
> > > +
> >
> > [...]
> >
> > > +
> > > +static void lt7911exc_remove(struct i2c_client *client)
> > > +{}
> >
> > If it's empty, it should be dropped. .remove is an optional callback.
> >
> it will be fixed in next version.
> 
> > > +
> > > +static const struct i2c_device_id lt7911exc_i2c_table[] = {
> > > +     {"lontium, lt7911exc"},
> >
> > Drop  the "lontium, " part. The I2C ids (unlike OF ids) don't have the
> > vendor part.
> >
> it will be fixed in next version.
> 
> > > +     {/* sentinel */}
> > > +};
> > > +
> > > +MODULE_DEVICE_TABLE(i2c, lt7911exc_i2c_table);
> > > +
> >
> > --
> > With best wishes
> > Dmitry

-- 
With best wishes
Dmitry