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Date:   Wed, 02 Feb 2022 10:16:49 +0000
From:   Paul Cercueil <paul@crapouillou.net>
Subject: Re: [PATCH v12 4/9] drm/ingenic: Add dw-hdmi driver specialization
 for jz4780
To:     "H. Nikolaus Schaller" <hns@goldelico.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Kees Cook <keescook@chromium.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Robert Foss <robert.foss@linaro.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Harry Wentland <harry.wentland@amd.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Maxime Ripard <maxime@cerno.tech>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Paul Boddie <paul@boddie.org.uk>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
        devicetree@vger.kernel.org, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org, letux-kernel@openphoenux.org,
        Jonas Karlman <jonas@kwiboo.se>,
        dri-devel@lists.freedesktop.org,
        Ezequiel Garcia <ezequiel@collabora.com>
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Hi Nikolaus,

Le lun., janv. 31 2022 at 13:26:50 +0100, H. Nikolaus Schaller 
<hns@goldelico.com> a ?crit :
> From: Paul Boddie <paul@boddie.org.uk>
> 
> A specialisation of the generic Synopsys HDMI driver is employed for
> JZ4780 HDMI support. This requires a new driver, plus device tree and
> configuration modifications.
> 
> Here we add Kconfig DRM_INGENIC_DW_HDMI, Makefile and driver code.
> 
> Signed-off-by: Paul Boddie <paul@boddie.org.uk>
> Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---
>  drivers/gpu/drm/ingenic/Kconfig           |   9 ++
>  drivers/gpu/drm/ingenic/Makefile          |   1 +
>  drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c | 104 
> ++++++++++++++++++++++
>  3 files changed, 114 insertions(+)
>  create mode 100644 drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c
> 
> diff --git a/drivers/gpu/drm/ingenic/Kconfig 
> b/drivers/gpu/drm/ingenic/Kconfig
> index 001f59fb06d56..ba4a650869cd8 100644
> --- a/drivers/gpu/drm/ingenic/Kconfig
> +++ b/drivers/gpu/drm/ingenic/Kconfig
> @@ -24,4 +24,13 @@ config DRM_INGENIC_IPU
> 
>  	  The Image Processing Unit (IPU) will appear as a second primary 
> plane.
> 
> +config DRM_INGENIC_DW_HDMI
> +	tristate "Ingenic specific support for Synopsys DW HDMI"
> +	depends on MACH_JZ4780
> +	select DRM_DW_HDMI
> +	help
> +	  Choose this option to enable Synopsys DesignWare HDMI based 
> driver.
> +	  If you want to enable HDMI on Ingenic JZ4780 based SoC, you should
> +	  select this option..

One dot is enough.

> +
>  endif
> diff --git a/drivers/gpu/drm/ingenic/Makefile 
> b/drivers/gpu/drm/ingenic/Makefile
> index d313326bdddbb..f10cc1c5a5f22 100644
> --- a/drivers/gpu/drm/ingenic/Makefile
> +++ b/drivers/gpu/drm/ingenic/Makefile
> @@ -1,3 +1,4 @@
>  obj-$(CONFIG_DRM_INGENIC) += ingenic-drm.o
>  ingenic-drm-y = ingenic-drm-drv.o
>  ingenic-drm-$(CONFIG_DRM_INGENIC_IPU) += ingenic-ipu.o
> +obj-$(CONFIG_DRM_INGENIC_DW_HDMI) += ingenic-dw-hdmi.o
> diff --git a/drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c 
> b/drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c
> new file mode 100644
> index 0000000000000..34e986dd606cf
> --- /dev/null
> +++ b/drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (C) 2011-2013 Freescale Semiconductor, Inc.
> + * Copyright (C) 2019, 2020 Paul Boddie <paul@boddie.org.uk>
> + *
> + * Derived from dw_hdmi-imx.c with i.MX portions removed.
> + * Probe and remove operations derived from rcar_dw_hdmi.c.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +
> +#include <drm/bridge/dw_hdmi.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_print.h>
> +
> +static const struct dw_hdmi_mpll_config ingenic_mpll_cfg[] = {
> +	{ 45250000,  { { 0x01e0, 0x0000 }, { 0x21e1, 0x0000 }, { 0x41e2, 
> 0x0000 } } },
> +	{ 92500000,  { { 0x0140, 0x0005 }, { 0x2141, 0x0005 }, { 0x4142, 
> 0x0005 } } },
> +	{ 148500000, { { 0x00a0, 0x000a }, { 0x20a1, 0x000a }, { 0x40a2, 
> 0x000a } } },
> +	{ 216000000, { { 0x00a0, 0x000a }, { 0x2001, 0x000f }, { 0x4002, 
> 0x000f } } },
> +	{ ~0UL,      { { 0x0000, 0x0000 }, { 0x0000, 0x0000 }, { 0x0000, 
> 0x0000 } } }
> +};
> +
> +static const struct dw_hdmi_curr_ctrl ingenic_cur_ctr[] = {
> +	/*pixelclk     bpp8    bpp10   bpp12 */
> +	{ 54000000,  { 0x091c, 0x091c, 0x06dc } },
> +	{ 58400000,  { 0x091c, 0x06dc, 0x06dc } },
> +	{ 72000000,  { 0x06dc, 0x06dc, 0x091c } },
> +	{ 74250000,  { 0x06dc, 0x0b5c, 0x091c } },
> +	{ 118800000, { 0x091c, 0x091c, 0x06dc } },
> +	{ 216000000, { 0x06dc, 0x0b5c, 0x091c } },
> +	{ ~0UL,      { 0x0000, 0x0000, 0x0000 } },
> +};
> +
> +/*
> + * Resistance term 133Ohm Cfg
> + * PREEMP config 0.00
> + * TX/CK level 10
> + */
> +static const struct dw_hdmi_phy_config ingenic_phy_config[] = {
> +	/*pixelclk   symbol   term   vlev */
> +	{ 216000000, 0x800d, 0x0005, 0x01ad},
> +	{ ~0UL,      0x0000, 0x0000, 0x0000}
> +};
> +
> +static enum drm_mode_status
> +ingenic_dw_hdmi_mode_valid(struct dw_hdmi *hdmi, void *data,
> +			   const struct drm_display_info *info,
> +			   const struct drm_display_mode *mode)
> +{
> +	if (mode->clock < 13500)
> +		return MODE_CLOCK_LOW;
> +	/* FIXME: Hardware is capable of 270MHz, but setup data is missing. 
> */
> +	if (mode->clock > 216000)
> +		return MODE_CLOCK_HIGH;
> +
> +	return MODE_OK;
> +}
> +
> +static struct dw_hdmi_plat_data ingenic_dw_hdmi_plat_data = {
> +	.mpll_cfg   = ingenic_mpll_cfg,
> +	.cur_ctr    = ingenic_cur_ctr,
> +	.phy_config = ingenic_phy_config,
> +	.mode_valid = ingenic_dw_hdmi_mode_valid,
> +	.output_port	= 1,
> +};
> +
> +static const struct of_device_id ingenic_dw_hdmi_dt_ids[] = {
> +	{ .compatible = "ingenic,jz4780-dw-hdmi" },
> +	{ /* Sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, ingenic_dw_hdmi_dt_ids);
> +
> +static void ingenic_dw_hdmi_cleanup(void *data)
> +{
> +	struct dw_hdmi *hdmi = (struct dw_hdmi *)data;
> +
> +	dw_hdmi_remove(hdmi);
> +}
> +
> +static int ingenic_dw_hdmi_probe(struct platform_device *pdev)
> +{
> +	struct dw_hdmi *hdmi;
> +
> +	hdmi = dw_hdmi_probe(pdev, &ingenic_dw_hdmi_plat_data);
> +	if (IS_ERR(hdmi))
> +		return PTR_ERR(hdmi);
> +
> +	return devm_add_action_or_reset(&pdev->dev, 
> ingenic_dw_hdmi_cleanup, hdmi);

Nitpick, but your probe function is so simple, you could just have a 
.remove callback instead of registering a devm action. Then you can 
just return PTR_ERR_OR_ZERO(hdmi).

Cheers,
-Paul

> +}
> +
> +static struct platform_driver ingenic_dw_hdmi_driver = {
> +	.probe  = ingenic_dw_hdmi_probe,
> +	.driver = {
> +		.name = "dw-hdmi-ingenic",
> +		.of_match_table = ingenic_dw_hdmi_dt_ids,
> +	},
> +};
> +module_platform_driver(ingenic_dw_hdmi_driver);
> +
> +MODULE_DESCRIPTION("JZ4780 Specific DW-HDMI Driver Extension");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:dwhdmi-ingenic");
> --
> 2.33.0
>