linux-kernel - Re: [PATCH 4/4] drm/bridge: anx7625: Add wait_hpd

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Date:   Wed, 6 Jul 2022 10:32:55 +0800
From:   Xin Ji <xji@...logixsemi.com>
To:     Hsin-Yi Wang <hsinyi@...omium.org>
Cc:     Robert Foss <robert.foss@...aro.org>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Sam Ravnborg <sam@...nborg.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <maxime@...no.tech>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] drm/bridge: anx7625: Add wait_hpd_asserted() callback

Hi Hsin-Yi, thanks for your patch, it looks good to me.

Reviewed-by: Xin Ji <xji@...logixsemi.com>

Thanks,
Xin

On Thu, Jun 30, 2022 at 12:05:50AM +0800, Hsin-Yi Wang wrote:
> Move hpd polling check into wait_hpd_asserted() callback. For the cases
> that aux transfer function wasn't used, do hpd polling check after pm
> runtime resume, which will power on the bridge.
> 
> Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
> ---
>  drivers/gpu/drm/bridge/analogix/anx7625.c | 33 ++++++++++++++++++-----
>  1 file changed, 27 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 59ddeba33652b..ea5a0b86fe52a 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -1443,23 +1443,24 @@ static int anx7625_read_hpd_status_p0(struct anx7625_data *ctx)
>  	return anx7625_reg_read(ctx, ctx->i2c.rx_p0_client, SYSTEM_STSTUS);
>  }
>  
> -static void anx7625_hpd_polling(struct anx7625_data *ctx)
> +static int _anx7625_hpd_polling(struct anx7625_data *ctx,
> +				 unsigned long wait_us)
>  {
>  	int ret, val;
>  	struct device *dev = &ctx->client->dev;
>  
>  	/* Interrupt mode, no need poll HPD status, just return */
>  	if (ctx->pdata.intp_irq)
> -		return;
> +		return 0;
>  
>  	ret = readx_poll_timeout(anx7625_read_hpd_status_p0,
>  				 ctx, val,
>  				 ((val & HPD_STATUS) || (val < 0)),
> -				 5000,
> -				 5000 * 100);
> +				 wait_us / 100,
> +				 wait_us);
>  	if (ret) {
>  		DRM_DEV_ERROR(dev, "no hpd.\n");
> -		return;
> +		return ret;
>  	}
>  
>  	DRM_DEV_DEBUG_DRIVER(dev, "system status: 0x%x. HPD raise up.\n", val);
> @@ -1472,6 +1473,23 @@ static void anx7625_hpd_polling(struct anx7625_data *ctx)
>  
>  	if (!ctx->pdata.panel_bridge && ctx->bridge_attached)
>  		drm_helper_hpd_irq_event(ctx->bridge.dev);
> +
> +	return 0;
> +}
> +
> +static int anx7625_wait_hpd_asserted(struct drm_dp_aux *aux,
> +				     unsigned long wait_us)
> +{
> +	struct anx7625_data *ctx = container_of(aux, struct anx7625_data, aux);
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	pm_runtime_get_sync(dev);
> +	ret = _anx7625_hpd_polling(ctx, wait_us);
> +	pm_runtime_mark_last_busy(dev);
> +	pm_runtime_put_autosuspend(dev);
> +
> +	return ret;
>  }
>  
>  static void anx7625_remove_edid(struct anx7625_data *ctx)
> @@ -1741,6 +1759,7 @@ static struct edid *anx7625_get_edid(struct anx7625_data *ctx)
>  	}
>  
>  	pm_runtime_get_sync(dev);
> +	_anx7625_hpd_polling(ctx, 5000 * 100);
>  	edid_num = sp_tx_edid_read(ctx, p_edid->edid_raw_data);
>  	pm_runtime_put_sync(dev);
>  
> @@ -2378,6 +2397,7 @@ static void anx7625_bridge_atomic_enable(struct drm_bridge *bridge,
>  	ctx->connector = connector;
>  
>  	pm_runtime_get_sync(dev);
> +	_anx7625_hpd_polling(ctx, 5000 * 100);
>  
>  	anx7625_dp_start(ctx);
>  }
> @@ -2497,7 +2517,6 @@ static int __maybe_unused anx7625_runtime_pm_resume(struct device *dev)
>  	mutex_lock(&ctx->lock);
>  
>  	anx7625_power_on_init(ctx);
> -	anx7625_hpd_polling(ctx);
>  
>  	mutex_unlock(&ctx->lock);
>  
> @@ -2589,6 +2608,7 @@ static int anx7625_i2c_probe(struct i2c_client *client,
>  	platform->aux.name = "anx7625-aux";
>  	platform->aux.dev = dev;
>  	platform->aux.transfer = anx7625_aux_transfer;
> +	platform->aux.wait_hpd_asserted = anx7625_wait_hpd_asserted;
>  	drm_dp_aux_init(&platform->aux);
>  
>  	if (anx7625_register_i2c_dummy_clients(platform, client) != 0) {
> @@ -2617,6 +2637,7 @@ static int anx7625_i2c_probe(struct i2c_client *client,
>  	if (!platform->pdata.low_power_mode) {
>  		anx7625_disable_pd_protocol(platform);
>  		pm_runtime_get_sync(dev);
> +		_anx7625_hpd_polling(platform, 5000 * 100);
>  	}
>  
>  	/* Add work function */
> -- 
> 2.37.0.rc0.161.g10f37bed90-goog