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

[Sam Ravnborg]

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 at chromium.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
> 
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