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From:   Jonas Karlman <jonas@kwiboo.se>
To:     Cheng-Yi Chiang <cychiang@chromium.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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        <linux-rockchip@lists.infradead.org>,
        David Airlie <airlied@linux.ie>,
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        "Takashi Iwai" <tiwai@suse.com>,
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Subject: Re: [alsa-devel] [PATCH 2/4] drm: bridge: dw-hdmi: Report connector
 status using callback
Thread-Topic: [alsa-devel] [PATCH 2/4] drm: bridge: dw-hdmi: Report connector
 status using callback
Thread-Index: AQHVMvTmlQAxzmEkvEygINjZy8KRxw==
Date:   Fri, 5 Jul 2019 05:45:49 +0000
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 <20190705042623.129541-3-cychiang@chromium.org>
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On 2019-07-05 06:26, Cheng-Yi Chiang wrote:
> Allow codec driver register callback function for plug event.
>
> The callback registration flow:
> dw-hdmi <--- hw-hdmi-i2s-audio <--- hdmi-codec
>
> dw-hdmi-i2s-audio implements hook_plugged_cb op
> so codec driver can register the callback.
>
> dw-hdmi implements set_plugged_cb op so platform device can register the
> callback.
>
> When connector plug/unplug event happens, report this event using the
> callback.
>
> Make sure that audio and drm are using the single source of truth for
> connector status.

I have a similar notification need for making a snd_ctl_notify() call from hdmi-codec when ELD changes,
see [1] for work in progress patches (part of a dw-hdmi multi-channel lpcm series I am preparing).

Any suggestions on how to handle a ELD change notification?
Should I use a similar pattern as in this series?
(I lost track of the hdmi-notifier/drm_audio_component discussion)

[1] https://github.com/Kwiboo/linux-rockchip/compare/54b40fdd264c7ed96017271eb6524cca4ff755ab...9c17284e8a8657e8b1da53a1c7ff056cbd8ce43c

Best regards,
Jonas

>
> Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>
> ---
>  .../gpu/drm/bridge/synopsys/dw-hdmi-audio.h   |  3 ++
>  .../drm/bridge/synopsys/dw-hdmi-i2s-audio.c   | 10 ++++++
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c     | 34 ++++++++++++++++++-
>  3 files changed, 46 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
> index 63b5756f463b..f523c590984e 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
> @@ -2,6 +2,8 @@
>  #ifndef DW_HDMI_AUDIO_H
>  #define DW_HDMI_AUDIO_H
>  
> +#include <sound/hdmi-codec.h>
> +
>  struct dw_hdmi;
>  
>  struct dw_hdmi_audio_data {
> @@ -17,6 +19,7 @@ struct dw_hdmi_i2s_audio_data {
>  
>  	void (*write)(struct dw_hdmi *hdmi, u8 val, int offset);
>  	u8 (*read)(struct dw_hdmi *hdmi, int offset);
> +	int (*set_plugged_cb)(struct dw_hdmi *hdmi, hdmi_codec_plugged_cb fn);
>  };
>  
>  #endif
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
> index 5cbb71a866d5..7b93cf05c985 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
> @@ -104,10 +104,20 @@ static int dw_hdmi_i2s_get_dai_id(struct snd_soc_component *component,
>  	return -EINVAL;
>  }
>  
> +static int dw_hdmi_i2s_hook_plugged_cb(struct device *dev, void *data,
> +				       hdmi_codec_plugged_cb fn)
> +{
> +	struct dw_hdmi_i2s_audio_data *audio = data;
> +	struct dw_hdmi *hdmi = audio->hdmi;
> +
> +	return audio->set_plugged_cb(hdmi, fn);
> +}
> +
>  static struct hdmi_codec_ops dw_hdmi_i2s_ops = {
>  	.hw_params	= dw_hdmi_i2s_hw_params,
>  	.audio_shutdown	= dw_hdmi_i2s_audio_shutdown,
>  	.get_dai_id	= dw_hdmi_i2s_get_dai_id,
> +	.hook_plugged_cb = dw_hdmi_i2s_hook_plugged_cb,
>  };
>  
>  static int snd_dw_hdmi_probe(struct platform_device *pdev)
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index 045b1b13fd0e..c69a399fc7ca 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -26,6 +26,8 @@
>  #include <drm/drm_probe_helper.h>
>  #include <drm/bridge/dw_hdmi.h>
>  
> +#include <sound/hdmi-codec.h>
> +
>  #include <uapi/linux/media-bus-format.h>
>  #include <uapi/linux/videodev2.h>
>  
> @@ -185,6 +187,9 @@ struct dw_hdmi {
>  	void (*disable_audio)(struct dw_hdmi *hdmi);
>  
>  	struct cec_notifier *cec_notifier;
> +
> +	hdmi_codec_plugged_cb plugged_cb;
> +	enum drm_connector_status last_connector_result;
>  };
>  
>  #define HDMI_IH_PHY_STAT0_RX_SENSE \
> @@ -209,6 +214,17 @@ static inline u8 hdmi_readb(struct dw_hdmi *hdmi, int offset)
>  	return val;
>  }
>  
> +static int hdmi_set_plugged_cb(struct dw_hdmi *hdmi, hdmi_codec_plugged_cb fn)
> +{
> +	mutex_lock(&hdmi->mutex);
> +	hdmi->plugged_cb = fn;
> +	if (hdmi->audio && !IS_ERR(hdmi->audio))
> +		fn(hdmi->audio,
> +		   hdmi->last_connector_result == connector_status_connected);
> +	mutex_unlock(&hdmi->mutex);
> +	return 0;
> +}
> +
>  static void hdmi_modb(struct dw_hdmi *hdmi, u8 data, u8 mask, unsigned reg)
>  {
>  	regmap_update_bits(hdmi->regm, reg << hdmi->reg_shift, mask, data);
> @@ -2044,6 +2060,7 @@ dw_hdmi_connector_detect(struct drm_connector *connector, bool force)
>  {
>  	struct dw_hdmi *hdmi = container_of(connector, struct dw_hdmi,
>  					     connector);
> +	enum drm_connector_status result;
>  
>  	mutex_lock(&hdmi->mutex);
>  	hdmi->force = DRM_FORCE_UNSPECIFIED;
> @@ -2051,7 +2068,20 @@ dw_hdmi_connector_detect(struct drm_connector *connector, bool force)
>  	dw_hdmi_update_phy_mask(hdmi);
>  	mutex_unlock(&hdmi->mutex);
>  
> -	return hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
> +	result = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
> +
> +	mutex_lock(&hdmi->mutex);
> +	if (result != hdmi->last_connector_result) {
> +		dev_dbg(hdmi->dev, "read_hpd result: %d", result);
> +		if (hdmi->plugged_cb && hdmi->audio && !IS_ERR(hdmi->audio)) {
> +			hdmi->plugged_cb(hdmi->audio,
> +					 result == connector_status_connected);
> +			hdmi->last_connector_result = result;
> +		}
> +	}
> +	mutex_unlock(&hdmi->mutex);
> +
> +	return result;
>  }
>  
>  static int dw_hdmi_connector_get_modes(struct drm_connector *connector)
> @@ -2460,6 +2490,7 @@ __dw_hdmi_probe(struct platform_device *pdev,
>  	hdmi->rxsense = true;
>  	hdmi->phy_mask = (u8)~(HDMI_PHY_HPD | HDMI_PHY_RX_SENSE);
>  	hdmi->mc_clkdis = 0x7f;
> +	hdmi->last_connector_result = connector_status_disconnected;
>  
>  	mutex_init(&hdmi->mutex);
>  	mutex_init(&hdmi->audio_mutex);
> @@ -2653,6 +2684,7 @@ __dw_hdmi_probe(struct platform_device *pdev,
>  		audio.hdmi	= hdmi;
>  		audio.write	= hdmi_writeb;
>  		audio.read	= hdmi_readb;
> +		audio.set_plugged_cb = hdmi_set_plugged_cb;
>  		hdmi->enable_audio = dw_hdmi_i2s_audio_enable;
>  		hdmi->disable_audio = dw_hdmi_i2s_audio_disable;
>