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Message-ID: <20190712104748.zlgxgdjbtj2gw4yz@shell.armlinux.org.uk>
Date: Fri, 12 Jul 2019 11:47:48 +0100
From: Russell King - ARM Linux admin <linux@...linux.org.uk>
To: Cheng-Yi Chiang <cychiang@...omium.org>
Cc: linux-kernel@...r.kernel.org, alsa-devel@...a-project.org,
dianders@...omium.org, Heiko Stuebner <heiko@...ech.de>,
linux-rockchip@...ts.infradead.org,
David Airlie <airlied@...ux.ie>,
dri-devel@...ts.freedesktop.org, Takashi Iwai <tiwai@...e.com>,
Liam Girdwood <lgirdwood@...il.com>, tzungbi@...omium.org,
Jaroslav Kysela <perex@...ex.cz>,
Hans Verkuil <hverkuil@...all.nl>,
Andrzej Hajda <a.hajda@...sung.com>,
Mark Brown <broonie@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Daniel Vetter <daniel@...ll.ch>, dgreid@...omium.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 2/5] drm: bridge: dw-hdmi: Report connector status
using callback
On Fri, Jul 12, 2019 at 06:04:40PM +0800, 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.
>
> Signed-off-by: Cheng-Yi Chiang <cychiang@...omium.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 | 55 ++++++++++++++++++-
> 3 files changed, 67 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..ce6646067472 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 +214,40 @@ static inline u8 hdmi_readb(struct dw_hdmi *hdmi, int offset)
> return val;
> }
>
> +static void handle_plugged_change(struct dw_hdmi *hdmi, bool plugged)
> +{
> + struct platform_device *codec_pdev;
> +
> + if (!hdmi->audio || IS_ERR(hdmi->audio))
> + return;
> + codec_pdev = platform_get_drvdata(hdmi->audio);
> + if (!codec_pdev || IS_ERR(codec_pdev))
> + return;
This looks fragile to me, poking about in another device's driver data
from another driver is really not a good design decision. I think this
can be simplified if the registration function took the function
pointer and the struct device pointer, and then you only need one test
below:
> + if (!hdmi->plugged_cb)
> + return;
> +
> + hdmi->plugged_cb(&codec_pdev->dev, plugged);
> +}
> +
> +static int hdmi_set_plugged_cb(struct dw_hdmi *hdmi, hdmi_codec_plugged_cb fn)
> +{
> + bool plugged;
> + struct platform_device *codec_pdev;
> +
> + if (!hdmi->audio || IS_ERR(hdmi->audio))
> + return -EINVAL;
Given the current code structure, how can this ever be true when the
function is called?
> + codec_pdev = platform_get_drvdata(hdmi->audio);
> + if (!codec_pdev || IS_ERR(codec_pdev))
> + return -EINVAL;
This doesn't seem like a good idea as I've pointed out above.
> +
> + mutex_lock(&hdmi->mutex);
> + hdmi->plugged_cb = fn;
> + plugged = hdmi->last_connector_result == connector_status_connected;
> + handle_plugged_change(hdmi, plugged);
> + mutex_unlock(&hdmi->mutex);
Should be a blank line here for readability.
> + 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 +2083,7 @@ 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 +2091,18 @@ 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);
> + handle_plugged_change(hdmi,
> + 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 +2511,7 @@ __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 +2705,7 @@ __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;
Why is this necessary?
The I2S audio driver already depends on the dw-hdmi module through its
use of functions already exported. Indirecting this through the
platform data makes no sense.
Just rename hdmi_set_plugged_cb to dw_hdmi_set_plugged_cb() and export
it for dw-hdmi-i2s-audio.c to use.
Thanks.
--
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