[PATCH 2/4] drm: ti-sn65dsi86: Check bridge connection failure

[Laurent Pinchart]

On Thu, Jun 20, 2024 at 09:43:05AM +0300, Tomi Valkeinen wrote:
> On 19/06/2024 22:32, Laurent Pinchart wrote:
> > Hi Jacopo,
> > 
> > Thank you for the patch.
> > 
> > On Wed, Jun 19, 2024 at 12:22:16PM +0200, Jacopo Mondi wrote:
> >> From: Phong Hoang <phong.hoang.wz at renesas.com>
> >>
> >> Add a check to the register access function when attaching a bridge
> >> device.
> 
> I think the desc is missing the "why". I'm guessing it's the first 
> register access to the IC, and thus verifies that it is accessible.

Isn't it a good idea in general to always check if I2C reads succeeded ?

> >>
> >> Signed-off-by: Phong Hoang <phong.hoang.wz at renesas.com>
> >> Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> > 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> > 
> >> ---
> >>   drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 +++++-
> >>   1 file changed, 5 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> >> index 84698a0b27a8..b7df53577987 100644
> >> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> >> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> >> @@ -696,6 +696,7 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
> >>   
> >>   static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 *pdata)
> >>   {
> >> +	int ret;
> >>   	int val;
> >>   	struct mipi_dsi_host *host;
> >>   	struct mipi_dsi_device *dsi;
> >> @@ -720,8 +721,11 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86
> >>   
> >>   	/* check if continuous dsi clock is required or not */
> >>   	pm_runtime_get_sync(dev);
> >> -	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
> >> +	ret = regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
> >>   	pm_runtime_put_autosuspend(dev);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >>   	if (!(val & DPPLL_CLK_SRC_DSICLK))
> >>   		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
> >>   

-- 
Regards,

Laurent Pinchart