Re: [PATCH] drm/bridge: ite-it6263: Add basic resume support

[Liu Ying]

Hi Biju,

On Wed, Apr 15, 2026 at 12:39:52PM +0100, Biju wrote:
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> 
> From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> 
> RZ/G3L SMARC EVK has a single-link LVDS connected to an ITE IT6263 chip.
> On the RZ/G3L SMARC EVK using PSCI, s2ram powers down the ITE IT6263 chip.
> Add a minimal system resume callback to restore the bridge after s2ram.
> The it6263_resume() callback re-establishes the LVDS I2C address and
> reconfigures the LVDS output. Wire it into a dev_pm_ops struct using
> SET_SYSTEM_SLEEP_PM_OPS with no suspend handler, and attach it to the
> driver via pm_sleep_ptr().

drm_mode_config_helper_{suspend,resume} called by a display controller
driver's system PM callbacks should be able to kind of provide system
PM for this bridge through this bridge driver's atomic_{disable,enable}
callbacks.  To do this, regulator enablement, GPIO reset control and
bridge initialization need to be moved from probe to atomic_enable,
plus regulator disablement needs to be added to atomic_disable.
The bridge initialization includes it6263_lvds_set_i2c_addr(),
it6263_lvds_config() and it6263_hdmi_config().  Make sense?

> 
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/bridge/ite-it6263.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/ite-it6263.c b/drivers/gpu/drm/bridge/ite-it6263.c
> index 4f3ebb7af4d4..9727ebef48e8 100644
> --- a/drivers/gpu/drm/bridge/ite-it6263.c
> +++ b/drivers/gpu/drm/bridge/ite-it6263.c
> @@ -906,6 +906,24 @@ static int it6263_probe(struct i2c_client *client)
>         return devm_drm_bridge_add(dev, &it->bridge);
>  }
> 
> +static int it6263_resume(struct device *dev)
> +{
> +       struct it6263 *it = dev_get_drvdata(dev);
> +       int ret;
> +
> +       ret = it6263_lvds_set_i2c_addr(it);
> +       if (ret)
> +               return ret;
> +
> +       it6263_lvds_config(it);
> +
> +       return 0;
> +}
> +
> +static const struct dev_pm_ops it6263_pm_ops = {
> +       SET_SYSTEM_SLEEP_PM_OPS(NULL, it6263_resume)
> +};
> +
>  static const struct of_device_id it6263_of_match[] = {
>         { .compatible = "ite,it6263", },
>         { }
> @@ -922,6 +940,7 @@ static struct i2c_driver it6263_driver = {
>         .probe = it6263_probe,
>         .driver = {
>                 .name = "it6263",
> +               .pm = pm_sleep_ptr(&it6263_pm_ops),
>                 .of_match_table = it6263_of_match,
>         },
>         .id_table = it6263_i2c_ids,
> --
> 2.43.0
> 

-- 
Regards,
Liu Ying