linux-kernel - Re: [PATCH] drm/bridge/synopsys: dsi: allow sending longer LP commands

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Message-ID: <4947d7a1-5816-5789-dfcd-e802a9463ffa@st.com>
Date:   Fri, 10 Jul 2020 08:47:14 +0000
From:   Philippe CORNU <philippe.cornu@...com>
To:     Yannick FERTRE <yannick.fertre@...com>,
        Benjamin GAIGNARD <benjamin.gaignard@...com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        "Alexandre TORGUE" <alexandre.torgue@...com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Antonio BORNEO <antonio.borneo@...com>
Subject: Re: [PATCH] drm/bridge/synopsys: dsi: allow sending longer LP
 commands



On 7/1/20 4:31 PM, Yannick Fertre wrote:
> From: Antonio Borneo <antonio.borneo@...com>
> 
> Current code does not properly computes the max length of LP
> commands that can be send during H or V sync, and rely on static
> values.
> Limiting the max LP length to 4 byte during the V-sync is overly
> conservative.
> 
> Relax the limit and allows longer LP commands (16 bytes) to be
> sent during V-sync.
> 
> Signed-off-by: Antonio Borneo <antonio.borneo@...com>
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 17 +++++++++--------
>   1 file changed, 9 insertions(+), 8 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..1a24ea648ef8 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -360,6 +360,15 @@ static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
>   	bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
>   	u32 val = 0;
>   
> +	/*
> +	 * TODO dw drv improvements
> +	 * largest packet sizes during hfp or during vsa/vpb/vfp
> +	 * should be computed according to byte lane, lane number and only
> +	 * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
> +	 */
> +	dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(16)
> +		  | INVACT_LPCMD_TIME(4));
> +
>   	if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
>   		val |= ACK_RQST_EN;
>   	if (lpm)
> @@ -611,14 +620,6 @@ static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
>   	dsi_write(dsi, DSI_DPI_VCID, DPI_VCID(dsi->channel));
>   	dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
>   	dsi_write(dsi, DSI_DPI_CFG_POL, val);
> -	/*
> -	 * TODO dw drv improvements
> -	 * largest packet sizes during hfp or during vsa/vpb/vfp
> -	 * should be computed according to byte lane, lane number and only
> -	 * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
> -	 */
> -	dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
> -		  | INVACT_LPCMD_TIME(4));
>   }
>   
>   static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
> 

(+ Antonio)

Hi Yannick & Antonio,

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