ALSA: cs5535audio: OLPC analog input support

This is a 2nd cut at adding support for OLPC analog input.

Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Andres Salomon <dilinger@debian.org>

sound/pci/cs5535audio/Makefile

@@ -5,5 +5,9 @@
 snd-cs5535audio-y := cs5535audio.o cs5535audio_pcm.o
 snd-cs5535audio-$(CONFIG_PM) += cs5535audio_pm.o
 
+ifdef CONFIG_OLPC
+snd-cs5535audio-objs += cs5535audio_olpc.o
+endif
+
 # Toplevel Module Dependency
 obj-$(CONFIG_SND_CS5535AUDIO) += snd-cs5535audio.o

sound/pci/cs5535audio/cs5535audio.c

@@ -171,6 +171,13 @@ static int __devinit snd_cs5535audio_mixer(struct cs5535audio *cs5535au)
 
 	snd_ac97_tune_hardware(cs5535au->ac97, ac97_quirks, ac97_quirk);
 
+	/* olpc_quirks is dummied out if not olpc */
+	err = olpc_quirks(card, cs5535au->ac97);
+	if (err < 0) {
+		snd_printk(KERN_ERR "olpc quirks failed\n");
+		return err;
+	}
+
 	return 0;
 }
 

sound/pci/cs5535audio/cs5535audio.h

@@ -92,6 +92,9 @@ struct cs5535audio {
 	struct snd_pcm_substream *playback_substream;
 	struct snd_pcm_substream *capture_substream;
 	struct cs5535audio_dma dmas[NUM_CS5535AUDIO_DMAS];
+#ifdef CONFIG_OLPC
+	int ec_analog_input_mode;
+#endif
 };
 
 #ifdef CONFIG_PM
@@ -99,6 +102,12 @@ int snd_cs5535audio_suspend(struct pci_dev *pci, pm_message_t state);
 int snd_cs5535audio_resume(struct pci_dev *pci);
 #endif
 
+#ifdef CONFIG_OLPC
+int olpc_quirks(struct snd_card *card, struct snd_ac97 *ac97);
+#else
+#define olpc_quirks(arg, arg2) (0)
+#endif
+
 int __devinit snd_cs5535audio_pcm(struct cs5535audio *cs5535audio);
 
 #endif /* __SOUND_CS5535AUDIO_H */

sound/pci/cs5535audio/cs5535audio_olpc.c

@@ -0,0 +1,113 @@
+#include <linux/olpc.h>
+#include <sound/driver.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/control.h>
+#include <sound/ac97_codec.h>
+#include "cs5535audio.h"
+
+/* OLPC has an additional feature on top of regular AD1888 codec
+features. This is support for an analog input mode. This is a
+2 step process. First, to turn off the AD1888 codec bias voltage
+and high pass filter. Second, to tell the embedded controller to
+reroute from a capacitive trace to a direct trace using an analog
+switch. The *_ec()s are what talk to that controller */
+
+static int snd_cs5535audio_ctl_info(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 1;
+	return 0;
+}
+
+#define AD1888_VREFOUT_EN_BIT (1 << 2)
+#define AD1888_HPF_EN_BIT (1 << 12)
+static int snd_cs5535audio_ctl_get(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct cs5535audio *cs5535au = snd_kcontrol_chip(kcontrol);
+	u16 reg1, reg2;
+
+	/* if either AD1888 VRef Bias and High Pass Filter are enabled
+	or the EC is not in analog mode then flag as not in analog mode.
+	No EC command to read current analog state so we cache that. */
+	reg1 = snd_ac97_read(cs5535au->ac97, AC97_AD_MISC);
+	reg2 = snd_ac97_read(cs5535au->ac97, AC97_AD_TEST2);
+
+	if ((reg1 & AD1888_VREFOUT_EN_BIT) && (reg2 & AD1888_HPF_EN_BIT) &&
+		cs5535au->ec_analog_input_mode)
+		ucontrol->value.integer.value[0] = 1;
+	else
+		ucontrol->value.integer.value[0] = 0;
+
+	return 0;
+}
+
+static int snd_cs5535audio_ctl_put(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	int err;
+	struct cs5535audio *cs5535au = snd_kcontrol_chip(kcontrol);
+	u8 value;
+	struct snd_ac97 *ac97 = cs5535au->ac97;
+
+	/* value is 1 if analog input is desired */
+	value = ucontrol->value.integer.value[0];
+
+	/* use ec mode as flag to determine if any change needed */
+	if (cs5535au->ec_analog_input_mode == value)
+		return 0;
+
+	/* sets High Z on VREF Bias if 1 */
+	if (value)
+		err = snd_ac97_update_bits(ac97, AC97_AD_MISC,
+				AD1888_VREFOUT_EN_BIT, AD1888_VREFOUT_EN_BIT);
+	else
+		err = snd_ac97_update_bits(ac97, AC97_AD_MISC,
+				AD1888_VREFOUT_EN_BIT, 0);
+	if (err < 0)
+		snd_printk(KERN_ERR "Error updating AD_MISC %d\n", err);
+
+	/* turns off High Pass Filter if 1 */
+	if (value)
+		err = snd_ac97_update_bits(ac97, AC97_AD_TEST2,
+				AD1888_HPF_EN_BIT, AD1888_HPF_EN_BIT);
+	else
+		err = snd_ac97_update_bits(ac97, AC97_AD_TEST2,
+				AD1888_HPF_EN_BIT, 0);
+	if (err < 0)
+		snd_printk(KERN_ERR "Error updating AD_TEST2 %d\n", err);
+
+	if (value)
+		err = write_ec_command(0x01); /* activate MIC_AC_OFF */
+	else
+		err = write_ec_command(0x02); /* deactivates MIC_AC_OFF */
+
+	if (err < 0)
+		snd_printk(KERN_ERR "Error talking to EC %d\n", err);
+
+	cs5535au->ec_analog_input_mode = value;
+
+	return 1;
+}
+
+static struct snd_kcontrol_new snd_cs5535audio_controls __devinitdata =
+{
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Analog Input Switch",
+	.info = snd_cs5535audio_ctl_info,
+	.get = snd_cs5535audio_ctl_get,
+	.put = snd_cs5535audio_ctl_put,
+	.private_value = 0
+};
+
+int __devinit olpc_quirks(struct snd_card *card, struct snd_ac97 *ac97)
+{
+	/* setup callback for mixer control that does analog input mode */
+	return snd_ctl_add(card, snd_ctl_new1(&snd_cs5535audio_controls,
+						ac97->private_data));
+}
+