[Intel-gfx] [PATCH 3/5] drm/dp: Implement I2C_M_STOP for i2c-over-aux

Dhinakaran Pandiyan dhinakaran.pandiyan at intel.com
Tue Dec 11 02:47:00 UTC 2018


On Fri, 2018-09-28 at 21:04 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Consult the I2C_M_STOP flag to determine whether to set the MOT bit
> or
> not. Makes it possible to send multiple messages in one go with
> stop+start generated between the messages (as opposed nothing or
> repstart depending on whether thr address/rw changed).
> 
> Not sure anyone has actual use for this but figured I'd handle it
> since I started to look at that flag for MST remote i2c xfers.
> 
Don't see the I2C_M_STOP flag anywhere in drm_edid.c, but the change
introduced here does make sense.

Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/drm_dp_helper.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c
> b/drivers/gpu/drm/drm_dp_helper.c
> index 37c01b6076ec..e85cea299d2a 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -884,7 +884,8 @@ static void drm_dp_i2c_msg_set_request(struct
> drm_dp_aux_msg *msg,
>  {
>  	msg->request = (i2c_msg->flags & I2C_M_RD) ?
>  		DP_AUX_I2C_READ : DP_AUX_I2C_WRITE;
> -	msg->request |= DP_AUX_I2C_MOT;
> +	if (!(i2c_msg->flags & I2C_M_STOP))
> +		msg->request |= DP_AUX_I2C_MOT;
>  }
>  
>  /*



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