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[2/3] ALSA: hda - define hda_get_display_clk to query CDCLK for Haswell/Broadwell

Message ID 8b11a79ce0c5e28330577c0d390ed87301677190.1404311751.git.mengdong.lin@intel.com (mailing list archive)
State Accepted
Delegated to: Takashi Iwai
Headers show

Commit Message

Lin, Mengdong July 2, 2014, 2:43 p.m. UTC 
From: Mengdong Lin <mengdong.lin@intel.com>

This patch defines hda_get_display_clk() to query Core Display Clock (CDCLK)
from the i915 display driver, via a private API i915_get_cdclk_freq().

The audio driver will set M/N values as per the CDCLK for restoring BCLK of
the display HD-A controller.

Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
diff mbox

Patch

diff --git a/sound/pci/hda/hda_i915.c b/sound/pci/hda/hda_i915.c
index e9e8a4a..76db293 100644
--- a/sound/pci/hda/hda_i915.c
+++ b/sound/pci/hda/hda_i915.c
@@ -24,6 +24,7 @@ 
 
 static int (*get_power)(void);
 static int (*put_power)(void);
+static int (*get_cdclk)(void);
 
 int hda_display_power(bool enable)
 {
@@ -38,6 +39,14 @@  int hda_display_power(bool enable)
 		return put_power();
 }
 
+int hda_get_display_clk(void)
+{
+	if (!get_cdclk)
+		return -ENODEV;
+
+	return get_cdclk();
+}
+
 int hda_i915_init(void)
 {
 	int err = 0;
@@ -55,6 +64,15 @@  int hda_i915_init(void)
 		return -ENODEV;
 	}
 
+	get_cdclk = symbol_request(i915_get_cdclk_freq);
+	if (!get_cdclk) {
+		symbol_put(i915_request_power_well);
+		get_power = NULL;
+		symbol_put(i915_release_power_well);
+		put_power = NULL;
+		return -ENODEV;
+	}
+
 	pr_debug("HDA driver get symbol successfully from i915 module\n");
 
 	return err;
@@ -70,6 +88,10 @@  int hda_i915_exit(void)
 		symbol_put(i915_release_power_well);
 		put_power = NULL;
 	}
+	if (get_cdclk) {
+		symbol_put(i915_get_cdclk_freq);
+		get_cdclk = NULL;
+	}
 
 	return 0;
 }
diff --git a/sound/pci/hda/hda_i915.h b/sound/pci/hda/hda_i915.h
index bfd835f..b4420e1 100644
--- a/sound/pci/hda/hda_i915.h
+++ b/sound/pci/hda/hda_i915.h
@@ -18,6 +18,7 @@ 
 
 #ifdef CONFIG_SND_HDA_I915
 int hda_display_power(bool enable);
+int hda_get_display_clk(void);
 int hda_i915_init(void);
 int hda_i915_exit(void);
 #else