Re: [PATCH] drm/bridge/synopsys: dsi: add support for non-continuous HS clock

From: Philippe CORNU <philippe.cornu@st.com>
To: Yannick FERTRE <yannick.fertre@st.com>,
	Benjamin GAIGNARD <benjamin.gaignard@st.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	"Alexandre TORGUE" <alexandre.torgue@st.com>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"linux-stm32@st-md-mailman.stormreply.com"
	<linux-stm32@st-md-mailman.stormreply.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Antonio BORNEO <antonio.borneo@st.com>
Subject: Re: [PATCH] drm/bridge/synopsys: dsi: add support for non-continuous HS clock
Date: Fri, 10 Jul 2020 08:47:23 +0000	[thread overview]
Message-ID: <8036e047-15c6-d259-66c2-c7f625faf759@st.com> (raw)
In-Reply-To: <20200701194234.18123-1-yannick.fertre@st.com>

On 7/1/20 9:42 PM, Yannick Fertre wrote:
> From: Antonio Borneo <antonio.borneo@st.com>
> 
> Current code enables the HS clock when video mode is started or to
> send out a HS command, and disables the HS clock to send out a LP
> command. This is not what DSI spec specify.
> 
> Enable HS clock either in command and in video mode.
> Set automatic HS clock management for panels and devices that
> support non-continuous HS clock.
> 
> Signed-off-by: Antonio Borneo <antonio.borneo@st.com>
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index d580b2aa4ce9..979acaa90d00 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -365,7 +365,6 @@ static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
>   	if (lpm)
>   		val |= CMD_MODE_ALL_LP;
>   
> -	dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
>   	dsi_write(dsi, DSI_CMD_MODE_CFG, val);
>   }
>   
> @@ -541,16 +540,22 @@ static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
>   static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
>   				 unsigned long mode_flags)
>   {
> +	u32 val;
> +
>   	dsi_write(dsi, DSI_PWR_UP, RESET);
>   
>   	if (mode_flags & MIPI_DSI_MODE_VIDEO) {
>   		dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
>   		dw_mipi_dsi_video_mode_config(dsi);
> -		dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
>   	} else {
>   		dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>   	}
>   
> +	val = PHY_TXREQUESTCLKHS;
> +	if (dsi->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS)
> +		val |= AUTO_CLKLANE_CTRL;
> +	dsi_write(dsi, DSI_LPCLK_CTRL, val);
> +
>   	dsi_write(dsi, DSI_PWR_UP, POWERUP);
>   }
>   
> 

(+ Antonio)

Hi Yannick & Antonio,

Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Tested-by: Philippe Cornu <philippe.cornu@st.com>

(Tested with the 3 patches named
drm/bridge/synopsys: dsi: allow LP commands in video mode
drm/bridge/synopsys: dsi: allow sending longer LP commands
drm/bridge/synopsys: dsi: add support for non-continuous HS clock
on various dsi bridges + stm32mp157 disco board)

Many thanks
Philippe :-)
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