[PATCH] drm/mediatek: mtk_dsi: enable hs clock during pre-enable

[AngeloGioacchino Del Regno]

Il 25/02/26 07:20, CK Hu (胡俊光) ha scritto:
> On Tue, 2026-01-20 at 12:36 +0100, Gary Bisson wrote:
>> External email : Please do not click links or open attachments until you have verified the sender or the content.
>>
>>
>> Some bridges, such as the TI SN65DSI83, require the HS clock to be
>> running in order to lock its PLL during its own pre-enable function.
>>
>> Without this change, the bridge gives the following error:
>> sn65dsi83 14-002c: failed to lock PLL, ret=-110
>> sn65dsi83 14-002c: Unexpected link status 0x01
>> sn65dsi83 14-002c: reset the pipe
>>
>> Move the necessary functions from enable to pre-enable.
> 
> Looks good to me, but this change the flow for all SoC and panel,
> so I would wait for more SoC and more panel test.
> 
> Reviewed-by: CK Hu <ck.hu at mediatek.com>
> 

Tested on
  - MT6795 Sony Xperia M5 w/DSI panel (with local changes, as the panel is not
    upstream yet)
  - MT8395 Radxa NIO-12L w/ Radxa Display 8HD

Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>

Nice patch, btw ;-)

Cheers,
Angelo

>>
>> Signed-off-by: Gary Bisson <bisson.gary at gmail.com>
>> ---
>> Tested on Tungsten510 module with sn65dsi83 + tm070jdhg30 panel.
>>
>> Left mtk_dsi_set_mode() as part of the enable function to mimic what is
>> done in the Samsung DSIM driver which is known to be working the TI
>> bridge.
>> ---
>>   drivers/gpu/drm/mediatek/mtk_dsi.c | 35 +++++++++++++++++------------------
>>   1 file changed, 17 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
>> index 0e2bcd5f67b7..b560245d1be9 100644
>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
>> @@ -672,6 +672,21 @@ static s32 mtk_dsi_switch_to_cmd_mode(struct mtk_dsi *dsi, u8 irq_flag, u32 t)
>>          }
>>   }
>>
>> +static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
>> +{
>> +       if (!dsi->lanes_ready) {
>> +               dsi->lanes_ready = true;
>> +               mtk_dsi_rxtx_control(dsi);
>> +               usleep_range(30, 100);
>> +               mtk_dsi_reset_dphy(dsi);
>> +               mtk_dsi_clk_ulp_mode_leave(dsi);
>> +               mtk_dsi_lane0_ulp_mode_leave(dsi);
>> +               mtk_dsi_clk_hs_mode(dsi, 0);
>> +               usleep_range(1000, 3000);
>> +               /* The reaction time after pulling up the mipi signal for dsi_rx */
>> +       }
>> +}
>> +
>>   static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>>   {
>>          struct device *dev = dsi->host.dev;
>> @@ -724,6 +739,8 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>>          mtk_dsi_set_vm_cmd(dsi);
>>          mtk_dsi_config_vdo_timing(dsi);
>>          mtk_dsi_set_interrupt_enable(dsi);
>> +       mtk_dsi_lane_ready(dsi);
>> +       mtk_dsi_clk_hs_mode(dsi, 1);
>>
>>          return 0;
>>   err_disable_engine_clk:
>> @@ -769,30 +786,12 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
>>          dsi->lanes_ready = false;
>>   }
>>
>> -static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
>> -{
>> -       if (!dsi->lanes_ready) {
>> -               dsi->lanes_ready = true;
>> -               mtk_dsi_rxtx_control(dsi);
>> -               usleep_range(30, 100);
>> -               mtk_dsi_reset_dphy(dsi);
>> -               mtk_dsi_clk_ulp_mode_leave(dsi);
>> -               mtk_dsi_lane0_ulp_mode_leave(dsi);
>> -               mtk_dsi_clk_hs_mode(dsi, 0);
>> -               usleep_range(1000, 3000);
>> -               /* The reaction time after pulling up the mipi signal for dsi_rx */
>> -       }
>> -}
>> -
>>   static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
>>   {
>>          if (dsi->enabled)
>>                  return;
>>
>> -       mtk_dsi_lane_ready(dsi);
>>          mtk_dsi_set_mode(dsi);
>> -       mtk_dsi_clk_hs_mode(dsi, 1);
>> -
>>          mtk_dsi_start(dsi);
>>
>>          dsi->enabled = true;
>>
>> ---
>> base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
>> change-id: 20260120-mtkdsi-29e4c84e7b38
>>
>> Best regards,
>> --
>> Gary Bisson <bisson.gary at gmail.com>
>>
>>
>