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Tue, 28 Apr 2020 03:19:02 -0700 (PDT) Date: Tue, 28 Apr 2020 12:19:00 +0200 From: Daniel Vetter To: Neil Armstrong Subject: Re: [PATCH v3 1/2] DRM: ARC: add HDMI 2.0 TX encoder support Message-ID: <20200428101900.GG3456981@phenom.ffwll.local> Mail-Followup-To: Neil Armstrong , Eugeniy Paltsev , dri-devel@lists.freedesktop.org, Alexey Brodkin , linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org, David Airlie , Maarten Lankhorst , Maxime Ripard , devicetree@vger.kernel.org, Rob Herring , Sam Ravnborg References: <20200414232929.22788-1-Eugeniy.Paltsev@synopsys.com> <20200414232929.22788-2-Eugeniy.Paltsev@synopsys.com> <20200415173320.GG3456981@phenom.ffwll.local> <267d49d8-a73a-0317-cb50-0f63f0ced049@baylibre.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <267d49d8-a73a-0317-cb50-0f63f0ced049@baylibre.com> X-Operating-System: Linux phenom 5.3.0-3-amd64 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200428_031905_910375_38D138B1 X-CRM114-Status: GOOD ( 38.48 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, David Airlie , Sam Ravnborg , Alexey Brodkin , Maarten Lankhorst , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Rob Herring , Maxime Ripard , linux-snps-arc@lists.infradead.org, Eugeniy Paltsev Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org On Tue, Apr 21, 2020 at 05:55:38PM +0200, Neil Armstrong wrote: > On 15/04/2020 19:33, Daniel Vetter wrote: > > On Wed, Apr 15, 2020 at 02:29:28AM +0300, Eugeniy Paltsev wrote: > >> The Synopsys ARC SoCs (like HSDK4xD) include on-chip DesignWare HDMI > >> encoders. Support them with a platform driver to provide platform glue > >> data to the dw-hdmi driver. > >> > >> Acked-by: Sam Ravnborg > >> Signed-off-by: Eugeniy Paltsev > >> --- > >> MAINTAINERS | 6 ++ > >> drivers/gpu/drm/Makefile | 2 +- > >> drivers/gpu/drm/arc/Kconfig | 7 ++ > >> drivers/gpu/drm/arc/Makefile | 1 + > >> drivers/gpu/drm/arc/arc-dw-hdmi.c | 116 ++++++++++++++++++++++++++++++ > >> 5 files changed, 131 insertions(+), 1 deletion(-) > >> create mode 100644 drivers/gpu/drm/arc/arc-dw-hdmi.c > >> > >> diff --git a/MAINTAINERS b/MAINTAINERS > >> index a6fbdf354d34..2aaed1190370 100644 > >> --- a/MAINTAINERS > >> +++ b/MAINTAINERS > >> @@ -1258,6 +1258,12 @@ S: Supported > >> F: drivers/gpu/drm/arc/ > >> F: Documentation/devicetree/bindings/display/snps,arcpgu.txt > >> > >> +ARC DW HDMI DRIVER > >> +M: Eugeniy Paltsev > >> +S: Supported > >> +F: drivers/gpu/drm/arc/arc-dw-hdmi.c > >> +F: Documentation/devicetree/bindings/display/bridge/snps,arc-dw-hdmi.yaml > >> + > >> ARCNET NETWORK LAYER > >> M: Michael Grzeschik > >> L: netdev@vger.kernel.org > >> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > >> index 6493088a0fdd..5b0bcf7f45cd 100644 > >> --- a/drivers/gpu/drm/Makefile > >> +++ b/drivers/gpu/drm/Makefile > >> @@ -109,7 +109,7 @@ obj-y += panel/ > >> obj-y += bridge/ > >> obj-$(CONFIG_DRM_FSL_DCU) += fsl-dcu/ > >> obj-$(CONFIG_DRM_ETNAVIV) += etnaviv/ > >> -obj-$(CONFIG_DRM_ARCPGU)+= arc/ > >> +obj-y += arc/ > >> obj-y += hisilicon/ > >> obj-$(CONFIG_DRM_ZTE) += zte/ > >> obj-$(CONFIG_DRM_MXSFB) += mxsfb/ > >> diff --git a/drivers/gpu/drm/arc/Kconfig b/drivers/gpu/drm/arc/Kconfig > >> index e8f3d63e0b91..baec9d2a4fba 100644 > >> --- a/drivers/gpu/drm/arc/Kconfig > >> +++ b/drivers/gpu/drm/arc/Kconfig > >> @@ -8,3 +8,10 @@ config DRM_ARCPGU > >> Choose this option if you have an ARC PGU controller. > >> > >> If M is selected the module will be called arcpgu. > >> + > >> +config DRM_ARC_DW_HDMI > >> + tristate "ARC DW HDMI" > >> + depends on DRM && OF > >> + select DRM_DW_HDMI > >> + help > >> + Synopsys DW HDMI driver for various ARC development boards > >> diff --git a/drivers/gpu/drm/arc/Makefile b/drivers/gpu/drm/arc/Makefile > >> index c7028b7427b3..7a156d8c2c3c 100644 > >> --- a/drivers/gpu/drm/arc/Makefile > >> +++ b/drivers/gpu/drm/arc/Makefile > >> @@ -1,3 +1,4 @@ > >> # SPDX-License-Identifier: GPL-2.0-only > >> arcpgu-y := arcpgu_crtc.o arcpgu_hdmi.o arcpgu_sim.o arcpgu_drv.o > >> obj-$(CONFIG_DRM_ARCPGU) += arcpgu.o > >> +obj-$(CONFIG_DRM_ARC_DW_HDMI) += arc-dw-hdmi.o > >> diff --git a/drivers/gpu/drm/arc/arc-dw-hdmi.c b/drivers/gpu/drm/arc/arc-dw-hdmi.c > >> new file mode 100644 > >> index 000000000000..46a6ee09b302 > >> --- /dev/null > >> +++ b/drivers/gpu/drm/arc/arc-dw-hdmi.c > >> @@ -0,0 +1,116 @@ > >> +// SPDX-License-Identifier: GPL-2.0+ > >> +// > >> +// Synopsys DW HDMI driver for various ARC development boards > >> +// > >> +// Copyright (C) 2020 Synopsys > >> +// Author: Eugeniy Paltsev > >> + > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> + > >> +static const struct dw_hdmi_mpll_config snps_hdmi_mpll_cfg[] = { > >> + { > >> + 27000000, { > >> + { 0x00B3, 0x0000 }, > >> + { 0x00B3, 0x0000 }, > >> + { 0x00B3, 0x0000 } > >> + }, > >> + }, { > >> + 74250000, { > >> + { 0x0072, 0x0001}, > >> + { 0x0072, 0x0001}, > >> + { 0x0072, 0x0001} > >> + }, > >> + }, { > >> + 148500000, { > >> + { 0x0051, 0x0002}, > >> + { 0x0051, 0x0002}, > >> + { 0x0051, 0x0002} > >> + }, > >> + }, { > >> + ~0UL, { > >> + { 0x00B3, 0x0000 }, > >> + { 0x00B3, 0x0000 }, > >> + { 0x00B3, 0x0000 }, > >> + }, > >> + } > >> +}; > >> + > >> +static const struct dw_hdmi_curr_ctrl snps_hdmi_cur_ctr[] = { > >> + /* pixelclk bpp8 bpp10 bpp12 */ > >> + { 27000000, { 0x0000, 0x0000, 0x0000 }, }, > >> + { 74250000, { 0x0008, 0x0008, 0x0008 }, }, > >> + { 148500000, { 0x001b, 0x001b, 0x001b }, }, > >> + { ~0UL, { 0x0000, 0x0000, 0x0000 }, } > >> +}; > >> + > >> + > >> +static const struct dw_hdmi_phy_config snps_hdmi_phy_config[] = { > >> + /* pixelclk symbol term vlev */ > >> + { 27000000, 0x8009, 0x0004, 0x0232}, > >> + { 74250000, 0x8009, 0x0004, 0x0232}, > >> + { 148500000, 0x8009, 0x0004, 0x0232}, > >> + { ~0UL, 0x8009, 0x0004, 0x0232} > >> +}; > >> + > >> +static struct dw_hdmi_plat_data snps_dw_hdmi_drv_data = { > >> + .mpll_cfg = snps_hdmi_mpll_cfg, > >> + .cur_ctr = snps_hdmi_cur_ctr, > >> + .phy_config = snps_hdmi_phy_config, > >> +}; > >> + > >> +static const struct of_device_id snps_dw_hdmi_dt_ids[] = { > >> + { .compatible = "snps,arc-dw-hdmi-hsdk", .data = &snps_dw_hdmi_drv_data }, > >> + { /* sentinel */ } > >> +}; > >> +MODULE_DEVICE_TABLE(of, snps_dw_hdmi_dt_ids); > >> + > >> +static int snps_dw_hdmi_probe(struct platform_device *pdev) > >> +{ > >> + const struct dw_hdmi_plat_data *plat_data; > >> + const struct of_device_id *match; > >> + struct dw_hdmi *hdmi; > >> + > >> + if (!pdev->dev.of_node) > >> + return -ENODEV; > >> + > >> + match = of_match_node(snps_dw_hdmi_dt_ids, pdev->dev.of_node); > >> + plat_data = match->data; > >> + > >> + hdmi = dw_hdmi_probe(pdev, plat_data); > > > > So this is kinda not how bridge drivers are supposed to be done nowadays, > > direct calling into the driver was the old way, and dw-hdmi still works > > like that. Modern way is roughly > > - bridge drivers bind automatically to any bridge they support > > - bridge drivers publish a bridge with drm_bridge_add() > > - the driver using the bridge fishes out with dt magic using > > of_drm_find_bridge() or another of the related of_ functions > > dw-hdmi is an IP, with some platform specific code and arrays to make it work > on very different systems, thus we can't use this scheme everywhere.... > > Some platforms (like r-car) uses the "right" model because the IP is integrated > as-is with the default PHY and as an independent IP on the system. > > It's definitely not the case on Rockchip/Amlogic/Allwinner systems, > and even worse on Amlogic system having a glue on top of the IP, and a > custom PHY instead of the Synopsys PHY. > > Thus it would be great this would be the case on a Synopsys SoC... but like > other platforms they have platform specific parameters. > > All this has been discussed and reviewed a few years ago, I would > personally prefer "fishing out a bridge using dt magic" instead having > 1k glue code around the IP. I'm not opposed to the per-instance glue code, that seems required. I'm kinda questioning where it is. Current design is that the glue code is in the drm_device driver side of things, with the drm_bridge somewhat awkward in-between. That doesn't seem very clean. I think more suitable for drm_bridge would be to push all the glue behind the drm_bridge (maybe into separate files in a drm/bridge/dw-hdmi/ directory), and the drm_device driver side simply grabs a drm_bridge and that's it. Then the drm_bridge abstraction lines up with the code organization again. Atm it's a bit a confusing state of things. Plan B would be to give up dw-hdmi being a drm_bridge, and rework dw-hdmi to be some kind of helper library to build a driver for a specific dw-hdmi instance. I think that would also be a clean design. But right now we kinda have a bit of both, so not really abstracted, but also not really a clean helper without midlayer either, and that doesn't look great. -Daniel > > Neil > > > > > I know a bit late, just spotted this because you brought your series here > > up in my arc cleanup series, but can you pls look into adjusting > > accordingly? > > > > I shouldn't take more than moving this binding here into the dw-hdmi > > driver, and switching arc itself over to the of_drm_find_bridge() call. > > That way we could slowly work to transform old bridge drivers like dw-hdmi > > to the new way, instead of adding more cases that will never get > > converted. > > > > Other upside is that arc stays a neat&tiny driver :-) > > > > Thanks, Daniel > > > >> + if (IS_ERR(hdmi)) > >> + return PTR_ERR(hdmi); > >> + > >> + platform_set_drvdata(pdev, hdmi); > >> + > >> + return 0; > >> +} > >> + > >> +static int snps_dw_hdmi_remove(struct platform_device *pdev) > >> +{ > >> + struct dw_hdmi *hdmi = platform_get_drvdata(pdev); > >> + > >> + dw_hdmi_remove(hdmi); > >> + > >> + return 0; > >> +} > >> + > >> +static struct platform_driver snps_dw_hdmi_platform_driver = { > >> + .probe = snps_dw_hdmi_probe, > >> + .remove = snps_dw_hdmi_remove, > >> + .driver = { > >> + .name = KBUILD_MODNAME, > >> + .of_match_table = snps_dw_hdmi_dt_ids, > >> + }, > >> +}; > >> +module_platform_driver(snps_dw_hdmi_platform_driver); > >> + > >> +MODULE_LICENSE("GPL v2"); > >> +MODULE_DESCRIPTION("ARC specific DW-HDMI driver extension"); > >> +MODULE_AUTHOR("Eugeniy Paltsev "); > >> -- > >> 2.21.1 > >> > > > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc