[ALSA] Add experimental support of aggressive AC97 power-saving mode

Added CONFIG_SND_AC97_POWER_SAVE kernel config to enable the support
of aggressive AC97 power-saving mode.  In this mode, the AC97
powerdown register bits are dynamically controlled at each open/close
of PCM streams.
The mode is activated via power_save option for snd-ac97-codec
driver.  As default it's off.  It can be turned on/off on the fly
via sysfs, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 32 insertions, 0 deletions

diff --git a/include/sound/ac97_codec.h b/include/sound/ac97_codec.h
index 758f8bf133c7..4c43521cc493 100644
--- a/include/sound/ac97_codec.h
+++ b/include/sound/ac97_codec.h
@@ -27,6 +27,7 @@
 
 #include <linux/bitops.h>
 #include <linux/device.h>
+#include <linux/workqueue.h>
 #include "pcm.h"
 #include "control.h"
 #include "info.h"
@@ -140,6 +141,20 @@
 #define AC97_GP_DRSS_1011       0x0000  /* LR(C) 10+11(+12) */
 #define AC97_GP_DRSS_78         0x0400  /* LR 7+8 */
 
+/* powerdown bits */
+#define AC97_PD_ADC_STATUS      0x0001  /* ADC status (RO) */
+#define AC97_PD_DAC_STATUS      0x0002  /* DAC status (RO) */
+#define AC97_PD_MIXER_STATUS    0x0004  /* Analog mixer status (RO) */
+#define AC97_PD_VREF_STATUS     0x0008  /* Vref status (RO) */
+#define AC97_PD_PR0             0x0100  /* Power down PCM ADCs and input MUX */
+#define AC97_PD_PR1             0x0200  /* Power down PCM front DAC */
+#define AC97_PD_PR2             0x0400  /* Power down Mixer (Vref still on) */
+#define AC97_PD_PR3             0x0800  /* Power down Mixer (Vref off) */
+#define AC97_PD_PR4             0x1000  /* Power down AC-Link */
+#define AC97_PD_PR5             0x2000  /* Disable internal clock usage */
+#define AC97_PD_PR6             0x4000  /* Headphone amplifier */
+#define AC97_PD_EAPD            0x8000  /* External Amplifer Power Down (EAPD) */
+
 /* extended audio ID bit defines */
 #define AC97_EI_VRA             0x0001  /* Variable bit rate supported */
 #define AC97_EI_DRA             0x0002  /* Double rate supported */
@@ -359,6 +374,7 @@
 #define AC97_SCAP_INV_EAPD      (1<<7)  /* inverted EAPD */
 #define AC97_SCAP_DETECT_BY_VENDOR (1<<8) /* use vendor registers for read tests */
 #define AC97_SCAP_NO_SPDIF      (1<<9)  /* don't build SPDIF controls */
+#define AC97_SCAP_EAPD_LED      (1<<10) /* EAPD as mute LED */
 
 /* ac97->flags */
 #define AC97_HAS_PC_BEEP        (1<<0)  /* force PC Speaker usage */
@@ -491,6 +507,12 @@ struct snd_ac97 {
         /* jack-sharing info */
         unsigned char indep_surround;
         unsigned char channel_mode;
+
+#ifdef CONFIG_SND_AC97_POWER_SAVE
+        unsigned int power_up;  /* power states */
+        struct workqueue_struct *power_workq;
+        struct work_struct power_work;
+#endif
         struct device dev;
 };
 
@@ -532,6 +554,15 @@ unsigned short snd_ac97_read(struct snd_ac97 *ac97, unsigned short reg);
 void snd_ac97_write_cache(struct snd_ac97 *ac97, unsigned short reg, unsigned short value);
 int snd_ac97_update(struct snd_ac97 *ac97, unsigned short reg, unsigned short value);
 int snd_ac97_update_bits(struct snd_ac97 *ac97, unsigned short reg, unsigned short mask, unsigned short value);
+#ifdef CONFIG_SND_AC97_POWER_SAVE
+int snd_ac97_update_power(struct snd_ac97 *ac97, int reg, int powerup);
+#else
+static inline int snd_ac97_update_power(struct snd_ac97 *ac97, int reg,
+                                        int powerup)
+{
+        return 0;
+}
+#endif
 #ifdef CONFIG_PM
 void snd_ac97_suspend(struct snd_ac97 *ac97);
 void snd_ac97_resume(struct snd_ac97 *ac97);
@@ -583,6 +614,7 @@ struct ac97_pcm {
                      copy_flag: 1,         /* lowlevel driver must fill all entries */
                      spdif: 1;             /* spdif pcm */
         unsigned short aslots;             /* active slots */
+        unsigned short cur_dbl;            /* current double-rate state */
         unsigned int rates;                /* available rates */
         struct {
                 unsigned short slots;      /* driver input: requested AC97 slot numbers */