From: Nicolas Boichat <drinkcat@chromium.org> To: Hsin-Yi Wang <hsinyi@chromium.org> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>, dri-devel@lists.freedesktop.org, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>, Devicetree List <devicetree@vger.kernel.org>, lkml <linux-kernel@vger.kernel.org>, Andrzej Hajda <a.hajda@samsung.com>, Neil Armstrong <narmstrong@baylibre.com>, Jonas Karlman <jonas@kwiboo.se>, Jernej Skrabec <jernej.skrabec@siol.net>, Philipp Zabel <p.zabel@pengutronix.de>, Enric Balletbo i Serra <enric.balletbo@collabora.com>, Matthias Brugger <mbrugger@suse.com>, Russell King <rmk+kernel@arm.linux.org.uk> Subject: Re: [PATCH RESEND 2/4] drm: bridge: anx7688: Add anx7688 bridge driver support. Date: Mon, 16 Dec 2019 18:19:24 +0800 [thread overview] Message-ID: <CANMq1KDh=ehp0RDFRLQ5OCTibrK=Uzp2UFVLM+7AhwpVp-X=yQ@mail.gmail.com> (raw) In-Reply-To: <CAJMQK-gFn8WeokxGfAZ-akNvdEbQhPj_3Ax2sD7Ti6JcSvjF4g@mail.gmail.com> On Mon, Dec 16, 2019 at 4:46 PM Hsin-Yi Wang <hsinyi@chromium.org> wrote: > > On Sat, Dec 14, 2019 at 6:38 AM Laurent Pinchart > <laurent.pinchart@ideasonboard.com> wrote: > > > > Hi Hsin-Yi and Nicolas, > > > > Thank you for the patch. > > > > On Wed, Dec 11, 2019 at 02:19:09PM +0800, Hsin-Yi Wang wrote: > > > From: Nicolas Boichat <drinkcat@chromium.org> > > > > > > ANX7688 is a HDMI to DP converter (as well as USB-C port controller), > > > that has an internal microcontroller. > > > > > > The only reason a Linux kernel driver is necessary is to reject > > > resolutions that require more bandwidth than what is available on > > > the DP side. DP bandwidth and lane count are reported by the bridge > > > via 2 registers on I2C. > > > > How about power, doesn't this chip have power supplies that potentially > > need to be controlled ? > > > Ideally we should add power supplies as well, but the power is > supplied by ec in mt8173 oak board. And we only have this board can > test this driver. If we add power supplies in driver we can't test it. To clarify a bit more, this is because this chip is actually a TCPC+mux+HDMI=>DP converter (https://www.analogix.com/en/products/convertersbridges/anx7688). In Chromebook architecture, TCPC+mux is controlled by the EC (including power and other control pins), and the only reason we need a driver for the HDMI=>DP converter is to get the number of lanes on the DP side and filter out resolutions. Also, the converter is on a different I2C address and it could almost be considered as a separate device. (of course we could write a kernel driver for the TCPC+mux but we'll leave that to others if there's ever a board that is built with the TCPC part connected to the AP) > > > Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> > > > Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org> > > > --- > > > drivers/gpu/drm/bridge/Kconfig | 9 + > > > drivers/gpu/drm/bridge/Makefile | 1 + > > > drivers/gpu/drm/bridge/analogix-anx7688.c | 202 ++++++++++++++++++++++ > > > 3 files changed, 212 insertions(+) > > > create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c > > > > > > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig > > > index 34362976cd6f..1f3fc6bec842 100644 > > > --- a/drivers/gpu/drm/bridge/Kconfig > > > +++ b/drivers/gpu/drm/bridge/Kconfig > > > @@ -16,6 +16,15 @@ config DRM_PANEL_BRIDGE > > > menu "Display Interface Bridges" > > > depends on DRM && DRM_BRIDGE > > > > > > +config DRM_ANALOGIX_ANX7688 > > > + tristate "Analogix ANX7688 bridge" > > > + select DRM_KMS_HELPER > > > + select REGMAP_I2C > > > + ---help--- > > > + ANX7688 is a transmitter to support DisplayPort over USB-C for > > > + smartphone and tablets. > > > + This driver only supports the HDMI to DP component of the chip. > > > + > > > config DRM_ANALOGIX_ANX78XX > > > tristate "Analogix ANX78XX bridge" > > > select DRM_KMS_HELPER > > > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile > > > index 4934fcf5a6f8..7a1e0ec032e6 100644 > > > --- a/drivers/gpu/drm/bridge/Makefile > > > +++ b/drivers/gpu/drm/bridge/Makefile > > > @@ -1,4 +1,5 @@ > > > # SPDX-License-Identifier: GPL-2.0 > > > +obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o > > > obj-$(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 > > > diff --git a/drivers/gpu/drm/bridge/analogix-anx7688.c b/drivers/gpu/drm/bridge/analogix-anx7688.c > > > new file mode 100644 > > > index 000000000000..baaed48d6201 > > > --- /dev/null > > > +++ b/drivers/gpu/drm/bridge/analogix-anx7688.c > > > @@ -0,0 +1,202 @@ > > > +// SPDX-License-Identifier: GPL-2.0-only > > > +/* > > > + * ANX7688 HDMI->DP bridge driver > > > + * > > > + * Copyright 2016 Google LLC > > > + */ > > > + > > > +#include <linux/i2c.h> > > > +#include <linux/module.h> > > > +#include <linux/regmap.h> > > > +#include <drm/drm_bridge.h> > > > + > > > +/* Register addresses */ > > > +#define VENDOR_ID_REG 0x00 > > > +#define DEVICE_ID_REG 0x02 > > > + > > > +#define FW_VERSION_REG 0x80 > > > + > > > +#define DP_BANDWIDTH_REG 0x85 > > > +#define DP_LANE_COUNT_REG 0x86 > > > > Are these registers defined by the ANX7688 hardware, or by the firmware > > running on the chip (and, I assume, developed by Google) ? > > > By firmware developed by ANX provided to Google. We asked for these registers to be added to ANX FW, and this is the FW that is used by all elm/hana Chromebooks (I have no idea about other ANX customers...). We have facilities to update the ANX FW from coreboot/depthcharge on Chromebooks, but that does not really matter: the factory FW of all MP Chromebooks does provide these registers. Thanks.
WARNING: multiple messages have this Message-ID (diff)
From: Nicolas Boichat <drinkcat@chromium.org> To: Hsin-Yi Wang <hsinyi@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com>, Devicetree List <devicetree@vger.kernel.org>, Jernej Skrabec <jernej.skrabec@siol.net>, Matthias Brugger <mbrugger@suse.com>, Neil Armstrong <narmstrong@baylibre.com>, David Airlie <airlied@linux.ie>, Jonas Karlman <jonas@kwiboo.se>, lkml <linux-kernel@vger.kernel.org>, dri-devel@lists.freedesktop.org, Rob Herring <robh+dt@kernel.org>, Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Enric Balletbo i Serra <enric.balletbo@collabora.com>, Russell King <rmk+kernel@arm.linux.org.uk> Subject: Re: [PATCH RESEND 2/4] drm: bridge: anx7688: Add anx7688 bridge driver support. Date: Mon, 16 Dec 2019 18:19:24 +0800 [thread overview] Message-ID: <CANMq1KDh=ehp0RDFRLQ5OCTibrK=Uzp2UFVLM+7AhwpVp-X=yQ@mail.gmail.com> (raw) In-Reply-To: <CAJMQK-gFn8WeokxGfAZ-akNvdEbQhPj_3Ax2sD7Ti6JcSvjF4g@mail.gmail.com> On Mon, Dec 16, 2019 at 4:46 PM Hsin-Yi Wang <hsinyi@chromium.org> wrote: > > On Sat, Dec 14, 2019 at 6:38 AM Laurent Pinchart > <laurent.pinchart@ideasonboard.com> wrote: > > > > Hi Hsin-Yi and Nicolas, > > > > Thank you for the patch. > > > > On Wed, Dec 11, 2019 at 02:19:09PM +0800, Hsin-Yi Wang wrote: > > > From: Nicolas Boichat <drinkcat@chromium.org> > > > > > > ANX7688 is a HDMI to DP converter (as well as USB-C port controller), > > > that has an internal microcontroller. > > > > > > The only reason a Linux kernel driver is necessary is to reject > > > resolutions that require more bandwidth than what is available on > > > the DP side. DP bandwidth and lane count are reported by the bridge > > > via 2 registers on I2C. > > > > How about power, doesn't this chip have power supplies that potentially > > need to be controlled ? > > > Ideally we should add power supplies as well, but the power is > supplied by ec in mt8173 oak board. And we only have this board can > test this driver. If we add power supplies in driver we can't test it. To clarify a bit more, this is because this chip is actually a TCPC+mux+HDMI=>DP converter (https://www.analogix.com/en/products/convertersbridges/anx7688). In Chromebook architecture, TCPC+mux is controlled by the EC (including power and other control pins), and the only reason we need a driver for the HDMI=>DP converter is to get the number of lanes on the DP side and filter out resolutions. Also, the converter is on a different I2C address and it could almost be considered as a separate device. (of course we could write a kernel driver for the TCPC+mux but we'll leave that to others if there's ever a board that is built with the TCPC part connected to the AP) > > > Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> > > > Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org> > > > --- > > > drivers/gpu/drm/bridge/Kconfig | 9 + > > > drivers/gpu/drm/bridge/Makefile | 1 + > > > drivers/gpu/drm/bridge/analogix-anx7688.c | 202 ++++++++++++++++++++++ > > > 3 files changed, 212 insertions(+) > > > create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c > > > > > > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig > > > index 34362976cd6f..1f3fc6bec842 100644 > > > --- a/drivers/gpu/drm/bridge/Kconfig > > > +++ b/drivers/gpu/drm/bridge/Kconfig > > > @@ -16,6 +16,15 @@ config DRM_PANEL_BRIDGE > > > menu "Display Interface Bridges" > > > depends on DRM && DRM_BRIDGE > > > > > > +config DRM_ANALOGIX_ANX7688 > > > + tristate "Analogix ANX7688 bridge" > > > + select DRM_KMS_HELPER > > > + select REGMAP_I2C > > > + ---help--- > > > + ANX7688 is a transmitter to support DisplayPort over USB-C for > > > + smartphone and tablets. > > > + This driver only supports the HDMI to DP component of the chip. > > > + > > > config DRM_ANALOGIX_ANX78XX > > > tristate "Analogix ANX78XX bridge" > > > select DRM_KMS_HELPER > > > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile > > > index 4934fcf5a6f8..7a1e0ec032e6 100644 > > > --- a/drivers/gpu/drm/bridge/Makefile > > > +++ b/drivers/gpu/drm/bridge/Makefile > > > @@ -1,4 +1,5 @@ > > > # SPDX-License-Identifier: GPL-2.0 > > > +obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o > > > obj-$(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 > > > diff --git a/drivers/gpu/drm/bridge/analogix-anx7688.c b/drivers/gpu/drm/bridge/analogix-anx7688.c > > > new file mode 100644 > > > index 000000000000..baaed48d6201 > > > --- /dev/null > > > +++ b/drivers/gpu/drm/bridge/analogix-anx7688.c > > > @@ -0,0 +1,202 @@ > > > +// SPDX-License-Identifier: GPL-2.0-only > > > +/* > > > + * ANX7688 HDMI->DP bridge driver > > > + * > > > + * Copyright 2016 Google LLC > > > + */ > > > + > > > +#include <linux/i2c.h> > > > +#include <linux/module.h> > > > +#include <linux/regmap.h> > > > +#include <drm/drm_bridge.h> > > > + > > > +/* Register addresses */ > > > +#define VENDOR_ID_REG 0x00 > > > +#define DEVICE_ID_REG 0x02 > > > + > > > +#define FW_VERSION_REG 0x80 > > > + > > > +#define DP_BANDWIDTH_REG 0x85 > > > +#define DP_LANE_COUNT_REG 0x86 > > > > Are these registers defined by the ANX7688 hardware, or by the firmware > > running on the chip (and, I assume, developed by Google) ? > > > By firmware developed by ANX provided to Google. We asked for these registers to be added to ANX FW, and this is the FW that is used by all elm/hana Chromebooks (I have no idea about other ANX customers...). We have facilities to update the ANX FW from coreboot/depthcharge on Chromebooks, but that does not really matter: the factory FW of all MP Chromebooks does provide these registers. Thanks. _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2019-12-16 10:19 UTC|newest] Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-12-11 6:19 [PATCH RESEND 0/4] drm: bridge: anx7688 and mux drivers Hsin-Yi Wang 2019-12-11 6:19 ` Hsin-Yi Wang 2019-12-11 6:19 ` [PATCH RESEND 1/4] dt-bindings: drm/bridge: analogix-anx7688: Add ANX7688 transmitter binding Hsin-Yi Wang 2019-12-11 6:19 ` Hsin-Yi Wang 2019-12-19 20:45 ` Rob Herring 2019-12-19 20:45 ` Rob Herring 2019-12-20 3:20 ` Hsin-Yi Wang 2019-12-20 3:20 ` Hsin-Yi Wang 2019-12-20 3:22 ` Laurent Pinchart 2019-12-20 3:22 ` Laurent Pinchart 2019-12-20 3:51 ` Hsin-Yi Wang 2019-12-20 3:51 ` Hsin-Yi Wang 2019-12-11 6:19 ` [PATCH RESEND 2/4] drm: bridge: anx7688: Add anx7688 bridge driver support Hsin-Yi Wang 2019-12-11 6:19 ` Hsin-Yi Wang 2019-12-12 11:50 ` Enric Balletbo i Serra 2019-12-12 11:50 ` Enric Balletbo i Serra 2019-12-13 22:38 ` Laurent Pinchart 2019-12-13 22:38 ` Laurent Pinchart 2019-12-16 8:45 ` Hsin-Yi Wang 2019-12-16 8:45 ` Hsin-Yi Wang 2019-12-16 10:19 ` Nicolas Boichat [this message] 2019-12-16 10:19 ` Nicolas Boichat 2019-12-16 16:39 ` Laurent Pinchart 2019-12-16 16:39 ` Laurent Pinchart 2019-12-17 0:20 ` Nicolas Boichat 2019-12-17 0:40 ` Nicolas Boichat 2019-12-17 0:40 ` Nicolas Boichat 2019-12-17 0:52 ` Laurent Pinchart 2019-12-17 0:52 ` Laurent Pinchart 2019-12-17 6:04 ` Nicolas Boichat 2019-12-17 6:04 ` Nicolas Boichat 2019-12-11 6:19 ` [PATCH RESEND 3/4] dt-bindings: drm/bridge: Add GPIO display mux binding Hsin-Yi Wang 2019-12-11 6:19 ` Hsin-Yi Wang 2019-12-13 13:53 ` Rob Herring 2019-12-13 13:53 ` Rob Herring 2019-12-16 7:16 ` Hsin-Yi Wang 2019-12-16 7:16 ` Hsin-Yi Wang 2019-12-19 20:48 ` Rob Herring 2019-12-19 20:48 ` Rob Herring 2019-12-20 3:57 ` Hsin-Yi Wang 2019-12-20 3:57 ` Hsin-Yi Wang 2019-12-11 6:19 ` [PATCH RESEND 4/4] drm: bridge: Generic GPIO mux driver Hsin-Yi Wang 2019-12-11 6:19 ` Hsin-Yi Wang 2019-12-12 11:54 ` Enric Balletbo i Serra 2019-12-12 11:54 ` Enric Balletbo i Serra 2019-12-13 22:33 ` Laurent Pinchart 2019-12-13 22:33 ` Laurent Pinchart 2019-12-16 8:44 ` Hsin-Yi Wang 2019-12-16 8:44 ` Hsin-Yi Wang -- strict thread matches above, loose matches on Subject: below -- 2019-12-09 14:50 [PATCH RESEND 0/4] drm: bridge: anx7688 and an optional feature Hsin-Yi Wang 2019-12-09 14:50 ` [PATCH RESEND 2/4] drm: bridge: anx7688: Add anx7688 bridge driver support Hsin-Yi Wang 2019-12-09 14:50 ` Hsin-Yi Wang
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to='CANMq1KDh=ehp0RDFRLQ5OCTibrK=Uzp2UFVLM+7AhwpVp-X=yQ@mail.gmail.com' \ --to=drinkcat@chromium.org \ --cc=a.hajda@samsung.com \ --cc=airlied@linux.ie \ --cc=daniel@ffwll.ch \ --cc=devicetree@vger.kernel.org \ --cc=dri-devel@lists.freedesktop.org \ --cc=enric.balletbo@collabora.com \ --cc=hsinyi@chromium.org \ --cc=jernej.skrabec@siol.net \ --cc=jonas@kwiboo.se \ --cc=laurent.pinchart@ideasonboard.com \ --cc=linux-kernel@vger.kernel.org \ --cc=mark.rutland@arm.com \ --cc=mbrugger@suse.com \ --cc=narmstrong@baylibre.com \ --cc=p.zabel@pengutronix.de \ --cc=rmk+kernel@arm.linux.org.uk \ --cc=robh+dt@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.