ALSA: hda - restore BCLK M/N value as per CDCLK for HSW/BDW display HDA controller

[karo-tx-linux.git] / sound / pci / hda / hda_i915.c

diff --git a/sound/pci/hda/hda_i915.c b/sound/pci/hda/hda_i915.c
index e9e8a4a4a9a14bd003a3a5d806405744262096ff..8b4940ba33d69ddcbc11fb35a080580b91edd70b 100644 (file)
--- a/sound/pci/hda/hda_i915.c
+++ b/sound/pci/hda/hda_i915.c
@@ -20,10 +20,20 @@
 #include <linux/module.h>
 #include <sound/core.h>
 #include <drm/i915_powerwell.h>
+#include "hda_priv.h"
 #include "hda_i915.h"
 
+/* Intel HSW/BDW display HDA controller Extended Mode registers.
+ * EM4 (M value) and EM5 (N Value) are used to convert CDClk (Core Display
+ * Clock) to 24MHz BCLK: BCLK = CDCLK * M / N
+ * The values will be lost when the display power well is disabled.
+ */
+#define ICH6_REG_EM4                   0x100c
+#define ICH6_REG_EM5                   0x1010
+
 static int (*get_power)(void);
 static int (*put_power)(void);
+static int (*get_cdclk)(void);
 
 int hda_display_power(bool enable)
 {
@@ -38,6 +48,43 @@ int hda_display_power(bool enable)
                return put_power();
 }
 
+void haswell_set_bclk(struct azx *chip)
+{
+       int cdclk_freq;
+       unsigned int bclk_m, bclk_n;
+
+       if (!get_cdclk)
+               return;
+
+       cdclk_freq = get_cdclk();
+       switch (cdclk_freq) {
+       case 337500:
+               bclk_m = 16;
+               bclk_n = 225;
+               break;
+
+       case 450000:
+       default: /* default CDCLK 450MHz */
+               bclk_m = 4;
+               bclk_n = 75;
+               break;
+
+       case 540000:
+               bclk_m = 4;
+               bclk_n = 90;
+               break;
+
+       case 675000:
+               bclk_m = 8;
+               bclk_n = 225;
+               break;
+       }
+
+       azx_writew(chip, EM4, bclk_m);
+       azx_writew(chip, EM5, bclk_n);
+}
+
+
 int hda_i915_init(void)
 {
        int err = 0;
@@ -55,6 +102,10 @@ int hda_i915_init(void)
                return -ENODEV;
        }
 
+       get_cdclk = symbol_request(i915_get_cdclk_freq);
+       if (!get_cdclk) /* may have abnormal BCLK and audio playback rate */
+               pr_warn("hda-i915: get_cdclk symbol get fail\n");
+
        pr_debug("HDA driver get symbol successfully from i915 module\n");
 
        return err;
@@ -70,6 +121,10 @@ 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;
 }