Re: [PATCH v3 06/13] drm: bridge: samsung-dsim: Add DSI init in bridge pre_enable()

From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Jagan Teki <jagan@amarulasolutions.com>,
	Andrzej Hajda <andrzej.hajda@intel.com>,
	Inki Dae <inki.dae@samsung.com>,
	Joonyoung Shim <jy0922.shim@samsung.com>,
	Seung-Woo Kim <sw0312.kim@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Frieder Schrempf <frieder.schrempf@kontron.de>,
	Fancy Fang <chen.fang@nxp.com>,
	Tim Harvey <tharvey@gateworks.com>,
	Michael Nazzareno Trimarchi <michael@amarulasolutions.com>,
	Adam Ford <aford173@gmail.com>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Robert Foss <robert.foss@linaro.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Tommaso Merciai <tommaso.merciai@amarulasolutions.com>,
	Marek Vasut <marex@denx.de>
Cc: Matteo Lisi <matteo.lisi@engicam.com>,
	dri-devel@lists.freedesktop.org,
	linux-samsung-soc@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	NXP Linux Team <linux-imx@nxp.com>,
	linux-amarula <linux-amarula@amarulasolutions.com>
Subject: Re: [PATCH v3 06/13] drm: bridge: samsung-dsim: Add DSI init in bridge pre_enable()
Date: Fri, 22 Jul 2022 17:35:01 +0200	[thread overview]
Message-ID: <8598bc48-ab5d-92fe-076a-c1e6ca74fccd@samsung.com> (raw)
In-Reply-To: <20220720155210.365977-7-jagan@amarulasolutions.com>

On 20.07.2022 17:52, Jagan Teki wrote:
> Host transfer() in DSI master will invoke only when the DSI commands
> are sent from DSI devices like DSI Panel or DSI bridges and this
> host transfer wouldn't invoke for I2C-based-DSI bridge drivers.
>
> Handling DSI host initialization in transfer calls misses the
> controller setup for I2C configured DSI bridges.
>
> This patch adds the DSI initialization from transfer to bridge
> pre_enable as the bridge pre_enable API is invoked by core as
> it is common across all classes of DSI device drivers.

This is still problematic in case of Exynos. Without a workaround like this

https://github.com/mszyprow/linux/commit/11bbfc61272da9610dd5c574bb8ef838dc150961

the display on the all real DSI panels on my Exynos based boards is broken.

>
> v3:
> * none
>
> v2:
> * check initialized state in samsung_dsim_init
>
> v1:
> * keep DSI init in host transfer
>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
>   drivers/gpu/drm/bridge/samsung-dsim.c | 18 ++++++++++++------
>   1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 9b74a3f98a17..b07909a52f2d 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1258,6 +1258,9 @@ static int samsung_dsim_init(struct samsung_dsim *dsi)
>   {
>   	const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
>   
> +	if (dsi->state & DSIM_STATE_INITIALIZED)
> +		return 0;
> +
>   	samsung_dsim_reset(dsi);
>   	samsung_dsim_enable_irq(dsi);
>   
> @@ -1270,6 +1273,8 @@ static int samsung_dsim_init(struct samsung_dsim *dsi)
>   	samsung_dsim_set_phy_ctrl(dsi);
>   	samsung_dsim_init_link(dsi);
>   
> +	dsi->state |= DSIM_STATE_INITIALIZED;
> +
>   	return 0;
>   }
>   
> @@ -1289,6 +1294,10 @@ static void samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge,
>   	}
>   
>   	dsi->state |= DSIM_STATE_ENABLED;
> +
> +	ret = samsung_dsim_init(dsi);
> +	if (ret)
> +		return;
>   }
>   
>   static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
> @@ -1464,12 +1473,9 @@ static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host,
>   	if (!(dsi->state & DSIM_STATE_ENABLED))
>   		return -EINVAL;
>   
> -	if (!(dsi->state & DSIM_STATE_INITIALIZED)) {
> -		ret = samsung_dsim_init(dsi);
> -		if (ret)
> -			return ret;
> -		dsi->state |= DSIM_STATE_INITIALIZED;
> -	}
> +	ret = samsung_dsim_init(dsi);
> +	if (ret)
> +		return ret;
>   
>   	ret = mipi_dsi_create_packet(&xfer.packet, msg);
>   	if (ret < 0)

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland