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Date:   Fri, 20 Jan 2023 10:16:41 +0100
From:   Sascha Hauer <s.hauer@pengutronix.de>
To:     Alibek Omarov <a1ba.omarov@gmail.com>
Cc:     alexander.sverdlin@siemens.com, macromorgan@hotmail.com,
        Sandy Huang <hjc@rock-chips.com>,
        Heiko =?iso-8859-15?Q?St=FCbner?= <heiko@sntech.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Michael Riesch <michael.riesch@wolfvision.net>,
        Peter Geis <pgwipeout@gmail.com>,
        Frank Wunderlich <frank-w@public-files.de>,
        Nicolas Frattaroli <frattaroli.nicolas@gmail.com>,
        Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
        dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] drm/rockchip: lvds: add rk3568 support
Message-ID: <20230120091641.GL24755@pengutronix.de>
References: <20230119184807.171132-1-a1ba.omarov@gmail.com>
 <20230119184807.171132-2-a1ba.omarov@gmail.com>
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On Thu, Jan 19, 2023 at 09:48:03PM +0300, Alibek Omarov wrote:
> One of the ports of RK3568 can be configured as LVDS, re-using the DSI DPHY
> 
> Signed-off-by: Alibek Omarov <a1ba.omarov@gmail.com>
> ---
>  drivers/gpu/drm/rockchip/rockchip_lvds.c | 144 +++++++++++++++++++++--
>  drivers/gpu/drm/rockchip/rockchip_lvds.h |  10 ++
>  2 files changed, 147 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/rockchip_lvds.c b/drivers/gpu/drm/rockchip/rockchip_lvds.c
> index 68f6ebb33460..83c60240af85 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_lvds.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_lvds.c
> @@ -433,6 +433,90 @@ static void px30_lvds_encoder_disable(struct drm_encoder *encoder)
>  	drm_panel_unprepare(lvds->panel);
>  }
>  
> +static int rk3568_lvds_poweron(struct rockchip_lvds *lvds)
> +{
> +	int ret;
> +
> +	ret = clk_enable(lvds->pclk);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = pm_runtime_get_sync(lvds->dev);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
> +		clk_disable(lvds->pclk);
> +		return ret;
> +	}
> +
> +	/* Enable LVDS mode */
> +	return regmap_update_bits(lvds->grf, RK3568_GRF_VO_CON2,
> +				  RK3568_LVDS0_MODE_EN(1),
> +				  RK3568_LVDS0_MODE_EN(1));

Isn't this the same as:

	regmap_write(lvds->grf, RK3568_GRF_VO_CON2, RK3568_LVDS0_MODE_EN(1));

Unless I am missing something I find a plain regmap_write() easier to
read.

> +}
> +
> +static void rk3568_lvds_poweroff(struct rockchip_lvds *lvds)
> +{
> +	regmap_update_bits(lvds->grf, RK3568_GRF_VO_CON2,
> +			   RK3568_LVDS0_MODE_EN(1) | RK3568_LVDS0_P2S_EN(1),
> +			   RK3568_LVDS0_MODE_EN(0) | RK3568_LVDS0_P2S_EN(0));

Same here:

	regmap_write(lvds->grf, RK3568_GRF_VO_CON2,
		     RK3568_LVDS0_MODE_EN(0) | RK3568_LVDS0_P2S_EN(0));

What about the RK3568_LVDS0_P2S_EN bit? This is set in probe() and
cleared here. For symmetry reasons shouldn't it be set in
rk3568_lvds_poweron() instead?

> +
> +	pm_runtime_put(lvds->dev);
> +	clk_disable(lvds->pclk);
> +}
> +
> +static int rk3568_lvds_grf_config(struct drm_encoder *encoder,
> +				struct drm_display_mode *mode)
> +{
> +	struct rockchip_lvds *lvds = encoder_to_lvds(encoder);
> +
> +	if (lvds->output != DISPLAY_OUTPUT_LVDS) {
> +		DRM_DEV_ERROR(lvds->dev, "Unsupported display output %d\n",
> +			      lvds->output);
> +		return -EINVAL;
> +	}
> +
> +	/* Set format */
> +	return regmap_update_bits(lvds->grf, RK3568_GRF_VO_CON0,
> +				  RK3568_LVDS0_SELECT(3),
> +				  RK3568_LVDS0_SELECT(lvds->format));

It seems lvds->format does not match what the register expects. We
have:

#define LVDS_VESA_24                            0
#define LVDS_JEIDA_24                           1
#define LVDS_VESA_18                            2
#define LVDS_JEIDA_18                           3

According to the reference manual the register expects:

lvdsformat_lvds0_select
 2'b00: VESA 24bit
 2'b01: JEIDA 24bit
 2'b10: JEIDA 18bit
 2'b11: VESA 18bit

I only have the RK3568 manual but no PX30 or RK3288 manual, so I can't say if
they changed the register mapping between the SoCs or if it's wrong on
the other SoCs as well.

BTW you correctly set the mask to RK3568_LVDS0_SELECT(3), but for the
PX30 it looks wrong:

	return regmap_update_bits(lvds->grf, PX30_LVDS_GRF_PD_VO_CON1,
				  PX30_LVDS_FORMAT(lvds->format),
				  PX30_LVDS_FORMAT(lvds->format));

I really think regmap_write() would be better to use here to avoid such
things.

> +
> +static void rk3568_lvds_encoder_enable(struct drm_encoder *encoder)
> +{
> +	struct rockchip_lvds *lvds = encoder_to_lvds(encoder);
> +	struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;

'mode' is unused.

> +	int ret;
> +
> +	drm_panel_prepare(lvds->panel);
> +
> +	ret = rk3568_lvds_poweron(lvds);
> +	if (ret) {
> +		DRM_DEV_ERROR(lvds->dev, "failed to power on LVDS: %d\n", ret);
> +		drm_panel_unprepare(lvds->panel);
> +		return;
> +	}
> +
> +	ret = rk3568_lvds_grf_config(encoder, mode);
> +	if (ret) {
> +		DRM_DEV_ERROR(lvds->dev, "failed to configure LVDS: %d\n", ret);
> +		drm_panel_unprepare(lvds->panel);
> +		return;
> +	}
> +
> +	drm_panel_enable(lvds->panel);
> +}
> +
> +static void rk3568_lvds_encoder_disable(struct drm_encoder *encoder)
> +{
> +	struct rockchip_lvds *lvds = encoder_to_lvds(encoder);
> +
> +	drm_panel_disable(lvds->panel);
> +	rk3568_lvds_poweroff(lvds);
> +	drm_panel_unprepare(lvds->panel);
> +}
> +
>  static const
>  struct drm_encoder_helper_funcs rk3288_lvds_encoder_helper_funcs = {
>  	.enable = rk3288_lvds_encoder_enable,
> @@ -447,6 +531,13 @@ struct drm_encoder_helper_funcs px30_lvds_encoder_helper_funcs = {
>  	.atomic_check = rockchip_lvds_encoder_atomic_check,
>  };
>  
> +static const
> +struct drm_encoder_helper_funcs rk3568_lvds_encoder_helper_funcs = {
> +	.enable = rk3568_lvds_encoder_enable,
> +	.disable = rk3568_lvds_encoder_disable,
> +	.atomic_check = rockchip_lvds_encoder_atomic_check,
> +};
> +
>  static int rk3288_lvds_probe(struct platform_device *pdev,
>  			     struct rockchip_lvds *lvds)
>  {
> @@ -491,6 +582,26 @@ static int rk3288_lvds_probe(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static int rockchip_lvds_phy_probe(struct platform_device *pdev,
> +				   struct rockchip_lvds *lvds)
> +{
> +	int ret;
> +
> +	lvds->dphy = devm_phy_get(&pdev->dev, "dphy");
> +	if (IS_ERR(lvds->dphy))
> +		return PTR_ERR(lvds->dphy);
> +
> +	ret = phy_init(lvds->dphy);
> +	if (ret)
> +		return ret;
> +
> +	ret = phy_set_mode(lvds->dphy, PHY_MODE_LVDS);
> +	if (ret)
> +		return ret;
> +
> +	return phy_power_on(lvds->dphy);
> +}

You factor out the steps done for px30 to a separate function in order
to reuse it on rk3568. You could make a separate patch from this to
make it easier to understand and to verify that there is no functional
change involved for the px30.

Sascha

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