[PATCH v3 5/5] drm: rcar-du: dsi: Fix VCLKSET write
Tomi Valkeinen
tomi.valkeinen at ideasonboard.com
Tue Aug 23 10:52:38 UTC 2022
On 22/08/2022 17:45, Laurent Pinchart wrote:
> Hi Tomi,
>
> Thank you for the patch.
>
> On Mon, Aug 22, 2022 at 05:34:01PM +0300, Tomi Valkeinen wrote:
>> From: Tomi Valkeinen <tomi.valkeinen+renesas at ideasonboard.com>
>>
>> rcar_mipi_dsi_startup() writes correct values to VCLKSET, but as it uses
>> or-operation to add the new values to the current value in the register,
>> it should first make sure the fields are cleared.
>>
>> Do this by using rcar_mipi_dsi_write() to write the VCLKSET_CKEN bit to
>> VCLKSET before the rest of the VCLKSET configuration.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas at ideasonboard.com>
>> ---
>> drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
>> index 06250f2f3499..b60a6d4a5d46 100644
>> --- a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
>> +++ b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
>> @@ -412,9 +412,10 @@ static int rcar_mipi_dsi_startup(struct rcar_mipi_dsi *dsi,
>> return ret;
>> }
>>
>> - /* Enable DOT clock */
>> - vclkset = VCLKSET_CKEN;
>> - rcar_mipi_dsi_set(dsi, VCLKSET, vclkset);
>> + /* Clear VCLKSET and enable DOT clock */
>> + rcar_mipi_dsi_write(dsi, VCLKSET, VCLKSET_CKEN);
>> +
>> + vclkset = 0;
>>
>> if (dsi_format == 24)
>> vclkset |= VCLKSET_BPP_24;
>
> You can replace one more set() with a write():
That's true. I'll send a new one.
> diff --git a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> index 06250f2f3499..2744ea23e6f6 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> @@ -414,7 +414,7 @@ static int rcar_mipi_dsi_startup(struct rcar_mipi_dsi *dsi,
>
> /* Enable DOT clock */
> vclkset = VCLKSET_CKEN;
> - rcar_mipi_dsi_set(dsi, VCLKSET, vclkset);
> + rcar_mipi_dsi_write(dsi, VCLKSET, vclkset);
>
> if (dsi_format == 24)
> vclkset |= VCLKSET_BPP_24;
> @@ -429,7 +429,7 @@ static int rcar_mipi_dsi_startup(struct rcar_mipi_dsi *dsi,
> vclkset |= VCLKSET_COLOR_RGB | VCLKSET_DIV(setup_info.div)
> | VCLKSET_LANE(dsi->lanes - 1);
>
> - rcar_mipi_dsi_set(dsi, VCLKSET, vclkset);
> + rcar_mipi_dsi_write(dsi, VCLKSET, vclkset);
>
> /* After setting VCLKSET register, enable VCLKEN */
> rcar_mipi_dsi_set(dsi, VCLKEN, VCLKEN_CKEN);
>
> I'll apply patches 1/5 to 4/5 to my tree already.
I'm not sure if 4 works correctly without 2.
Tomi
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