drm: bridge/dw_hdmi-ahb-audio: parse ELD from HDMI driver

Parse the ELD (EDID like data) stored from the HDMI driver to restrict
the sample rates and channels which are available to ALSA.  This causes
the ALSA device to reflect the capabilities of the overall audio path,
not just what is supported at the HDMI source interface level.

Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 0d0a4f7..6dddd39 100644 (file)
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -15,6 +15,7 @@ config DRM_DW_HDMI_AHB_AUDIO
        tristate "Synopsis Designware AHB Audio interface"
        depends on DRM_DW_HDMI && SND
        select SND_PCM
+       select SND_PCM_ELD
        select SND_PCM_IEC958
        help
          Support the AHB Audio interface which is part of the Synopsis

diff --git a/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c b/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
index bf37931..fbcef26 100644 (file)
--- a/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
@@ -12,11 +12,13 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <drm/bridge/dw_hdmi.h>
+#include <drm/drm_edid.h>
 
 #include <sound/asoundef.h>
 #include <sound/core.h>
 #include <sound/initval.h>
 #include <sound/pcm.h>
+#include <sound/pcm_drm_eld.h>
 #include <sound/pcm_iec958.h>
 
 #include "dw_hdmi-audio.h"
@@ -286,6 +288,10 @@ static int dw_hdmi_open(struct snd_pcm_substream *substream)
 
        runtime->hw = dw_hdmi_hw;
 
+       ret = snd_pcm_hw_constraint_eld(runtime, dw->data.eld);
+       if (ret < 0)
+               return ret;
+
        ret = snd_pcm_limit_hw_rates(runtime);
        if (ret < 0)
                return ret;

diff --git a/drivers/gpu/drm/bridge/dw_hdmi-audio.h b/drivers/gpu/drm/bridge/dw_hdmi-audio.h
index 1e84011..91f631b 100644 (file)
--- a/drivers/gpu/drm/bridge/dw_hdmi-audio.h
+++ b/drivers/gpu/drm/bridge/dw_hdmi-audio.h
@@ -8,6 +8,7 @@ struct dw_hdmi_audio_data {
        void __iomem *base;
        int irq;
        struct dw_hdmi *hdmi;
+       u8 *eld;
 };
 
 #endif

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index d61a9fb..70e7a93 100644 (file)
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -1533,6 +1533,8 @@ static int dw_hdmi_connector_get_modes(struct drm_connector *connector)
                hdmi->sink_has_audio = drm_detect_monitor_audio(edid);
                drm_mode_connector_update_edid_property(connector, edid);
                ret = drm_add_edid_modes(connector, edid);
+               /* Store the ELD */
+               drm_edid_to_eld(connector, edid);
                kfree(edid);
        } else {
                dev_dbg(hdmi->dev, "failed to get edid\n");
@@ -1873,6 +1875,7 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
                audio.base = hdmi->regs;
                audio.irq = irq;
                audio.hdmi = hdmi;
+               audio.eld = hdmi->connector.eld;
 
                pdevinfo.name = "dw-hdmi-ahb-audio";
                pdevinfo.data = &audio;