linux-kernel - Re: [PATCH] drm/bridge: ti-sn65dsi86: Clear old error bits before AUX transfers

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Message-ID: <20200518180148.GB770425@ravnborg.org>
Date:   Mon, 18 May 2020 20:01:48 +0200
From:   Sam Ravnborg <sam@...nborg.org>
To:     Douglas Anderson <dianders@...omium.org>
Cc:     Andrzej Hajda <a.hajda@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        robdclark@...omium.org, Jernej Skrabec <jernej.skrabec@...l.net>,
        Jonas Karlman <jonas@...boo.se>,
        David Airlie <airlied@...ux.ie>, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        Sandeep Panda <spanda@...eaurora.org>, seanpaul@...omium.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/bridge: ti-sn65dsi86: Clear old error bits before
 AUX transfers

On Fri, May 08, 2020 at 04:33:29PM -0700, Douglas Anderson wrote:
> The AUX channel transfer error bits in the status register are latched
> and need to be cleared.  Clear them before doing our transfer so we
> don't see old bits and get confused.
> 
> Without this patch having a single failure would mean that all future
> transfers would look like they failed.
> 
> Fixes: b814ec6d4535 ("drm/bridge: ti-sn65dsi86: Implement AUX channel")
> Signed-off-by: Douglas Anderson <dianders@...omium.org>

Applied.

	Sam

> ---
> 
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index 6ad688b320ae..d865cc2565bc 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -827,6 +827,12 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
>  				     buf[i]);
>  	}
>  
> +	/* Clear old status bits before start so we don't get confused */
> +	regmap_write(pdata->regmap, SN_AUX_CMD_STATUS_REG,
> +		     AUX_IRQ_STATUS_NAT_I2C_FAIL |
> +		     AUX_IRQ_STATUS_AUX_RPLY_TOUT |
> +		     AUX_IRQ_STATUS_AUX_SHORT);
> +
>  	regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val | AUX_CMD_SEND);
>  
>  	ret = regmap_read_poll_timeout(pdata->regmap, SN_AUX_CMD_REG, val,
> -- 
> 2.26.2.645.ge9eca65c58-goog
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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