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Date:   Wed, 11 May 2022 18:01:12 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Jayshri Pawar <jpawar@cadence.com>
Cc:     dri-devel@lists.freedesktop.org, daniel@ffwll.ch, airlied@linux.ie,
        andrzej.hajda@intel.com, narmstrong@baylibre.com,
        robert.foss@linaro.org, jonas@kwiboo.se, jernej.skrabec@gmail.com,
        linux-kernel@vger.kernel.org, mparab@cadence.com,
        sjakhade@cadence.com, nm@ti.com, yogeshs@ti.com, kishon@ti.com
Subject: Re: [PATCH] drm/bridge: cdns-dsi: Add support for pre_enable and
 post_enable control functions.
Message-ID: <YnvPuD3rgzCVTNxx@pendragon.ideasonboard.com>
References: <20220411140606.15654-1-jpawar@cadence.com>
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In-Reply-To: <20220411140606.15654-1-jpawar@cadence.com>
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Hi Jayshri,

Thank you for the patch.

On Mon, Apr 11, 2022 at 04:06:06PM +0200, Jayshri Pawar wrote:
> From: jpawar <jpawar@cadence.com>
> 
> Add support for pre_enable and post_enable drm bridge control functions.
> Making sure that host to be prepared before panel is powered up,
> for the panels like TC358762.
> 
> Signed-off-by: jpawar <jpawar@cadence.com>
> ---
>  drivers/gpu/drm/bridge/cdns-dsi.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
> index 829e1a144656..20bece84ff8c 100644
> --- a/drivers/gpu/drm/bridge/cdns-dsi.c
> +++ b/drivers/gpu/drm/bridge/cdns-dsi.c
> @@ -462,6 +462,7 @@ struct cdns_dsi {
>  	struct reset_control *dsi_p_rst;
>  	struct clk *dsi_sys_clk;
>  	bool link_initialized;
> +	bool phy_initialized;
>  	struct phy *dphy;
>  };
>  
> @@ -711,11 +712,21 @@ static void cdns_dsi_bridge_disable(struct drm_bridge *bridge)
>  	pm_runtime_put(dsi->base.dev);
>  }
>  
> +static void cdns_dsi_bridge_post_disable(struct drm_bridge *bridge)
> +{
> +	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
> +	struct cdns_dsi *dsi = input_to_dsi(input);
> +
> +	pm_runtime_put(dsi->base.dev);
> +}
> +
>  static void cdns_dsi_hs_init(struct cdns_dsi *dsi)
>  {
>  	struct cdns_dsi_output *output = &dsi->output;
>  	u32 status;
>  
> +	if (dsi->phy_initialized)
> +		return;
>  	/*
>  	 * Power all internal DPHY blocks down and maintain their reset line
>  	 * asserted before changing the DPHY config.
> @@ -739,6 +750,7 @@ static void cdns_dsi_hs_init(struct cdns_dsi *dsi)
>  	writel(DPHY_CMN_PSO | DPHY_ALL_D_PDN | DPHY_C_PDN | DPHY_CMN_PDN |
>  	       DPHY_D_RSTB(output->dev->lanes) | DPHY_C_RSTB,
>  	       dsi->regs + MCTL_DPHY_CFG0);
> +	dsi->phy_initialized = true;
>  }
>  
>  static void cdns_dsi_init_link(struct cdns_dsi *dsi)
> @@ -914,11 +926,25 @@ static void cdns_dsi_bridge_enable(struct drm_bridge *bridge)
>  	writel(tmp, dsi->regs + MCTL_MAIN_EN);
>  }
>  
> +static void cdns_dsi_bridge_pre_enable(struct drm_bridge *bridge)
> +{
> +	struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
> +	struct cdns_dsi *dsi = input_to_dsi(input);
> +
> +	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0))

This should use pm_runtime_resume_and_get(), otherwise you need to call
pm_runtime_put_noidle() on failure.

> +		return;
> +
> +	cdns_dsi_init_link(dsi);
> +	cdns_dsi_hs_init(dsi);
> +}
> +
>  static const struct drm_bridge_funcs cdns_dsi_bridge_funcs = {
>  	.attach = cdns_dsi_bridge_attach,
>  	.mode_valid = cdns_dsi_bridge_mode_valid,
>  	.disable = cdns_dsi_bridge_disable,
> +	.pre_enable = cdns_dsi_bridge_pre_enable,
>  	.enable = cdns_dsi_bridge_enable,
> +	.post_disable = cdns_dsi_bridge_post_disable,
>  };
>  
>  static int cdns_dsi_attach(struct mipi_dsi_host *host,

-- 
Regards,

Laurent Pinchart