[alsa-devel] [PATCH 4/4] snd-maestro3: Make hardware volume buttons an input device

Hans de Goede hdegoede at redhat.com
Wed Apr 21 17:04:09 CEST 2010


While working on the sound suspend / resume problems with my laptop
I noticed that the hardware volume handling code in essence just detects
key presses, and then does some hardcoded modification of the master volume
based on which key is pressed.

This made me think that clearly the right thing to do here is just report
these keypresses to userspace as keypresses using an input device and let
userspace decide what to with them.

This patch does this, getting rid of the ugly direct ac97 writes from
the tasklet, the ac97lock and the need for using a tasklet in general.

As an added bonus the keys now work identical to volume keys on a (usb)
keyboard with multimedia keys, providing visual feedback of the volume
level change, and a better range of the volume control (with a properly
configured desktop environment).

Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
 sound/pci/maestro3.c |  134 +++++++++++++++++++++++++++-----------------------
 1 files changed, 73 insertions(+), 61 deletions(-)

diff --git a/sound/pci/maestro3.c b/sound/pci/maestro3.c
index 0ed634a..135240d 100644
--- a/sound/pci/maestro3.c
+++ b/sound/pci/maestro3.c
@@ -41,6 +41,7 @@
 #include <linux/vmalloc.h>
 #include <linux/moduleparam.h>
 #include <linux/firmware.h>
+#include <linux/input.h>
 #include <sound/core.h>
 #include <sound/info.h>
 #include <sound/control.h>
@@ -806,6 +807,10 @@ struct m3_dma {
 struct snd_m3 {
 	
 	struct snd_card *card;
+#ifdef CONFIG_INPUT
+	struct input_dev *input_dev;
+	char phys[64];			/* physical device path */
+#endif
 
 	unsigned long iobase;
 
@@ -844,11 +849,7 @@ struct snd_m3 {
 	struct m3_dma *substreams;
 
 	spinlock_t reg_lock;
-	spinlock_t ac97_lock;
 
-	struct snd_kcontrol *master_switch;
-	struct snd_kcontrol *master_volume;
-	struct tasklet_struct hwvol_tq;
 	unsigned int in_suspend;
 
 #ifdef CONFIG_PM
@@ -1602,11 +1603,9 @@ static void snd_m3_update_ptr(struct snd_m3 *chip, struct m3_dma *s)
    (without wrap around) in response to volume button presses and then
    generating an interrupt. The pair of counters is stored in bits 1-3 and 5-7
    of a byte wide register. The meaning of bits 0 and 4 is unknown. */
-static void snd_m3_update_hw_volume(unsigned long private_data)
+static void snd_m3_update_hw_volume(struct snd_m3 *chip)
 {
-	struct snd_m3 *chip = (struct snd_m3 *) private_data;
-	int x, val;
-	unsigned long flags;
+	int x, key = 0;
 
 	/* Figure out which volume control button was pushed,
 	   based on differences from the default register
@@ -1632,51 +1631,34 @@ static void snd_m3_update_hw_volume(unsigned long private_data)
 	if (chip->in_suspend)
 		return;
 
-	if (!chip->master_switch || !chip->master_volume)
+#ifdef CONFIG_INPUT
+	if (!chip->input_dev)
 		return;
 
-	/* FIXME: we can't call snd_ac97_* functions since here is in tasklet. */
-	spin_lock_irqsave(&chip->ac97_lock, flags);
-
-	val = chip->ac97->regs[AC97_MASTER_VOL];
 	switch (x) {
 	case 0x88:
 		/* The counters have not changed, yet we've received a HV
 		   interrupt. According to tests run by various people this
 		   happens when pressing the mute button. */
-		val ^= 0x8000;
-		chip->ac97->regs[AC97_MASTER_VOL] = val;
-		outw(val, chip->iobase + CODEC_DATA);
-		outb(AC97_MASTER_VOL, chip->iobase + CODEC_COMMAND);
-		snd_ctl_notify(chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
-			       &chip->master_switch->id);
+		key = KEY_MUTE;
 		break;
 	case 0xaa:
 		/* counters increased by 1 -> volume up */
-		if ((val & 0x7f) > 0)
-			val--;
-		if ((val & 0x7f00) > 0)
-			val -= 0x0100;
-		chip->ac97->regs[AC97_MASTER_VOL] = val;
-		outw(val, chip->iobase + CODEC_DATA);
-		outb(AC97_MASTER_VOL, chip->iobase + CODEC_COMMAND);
-		snd_ctl_notify(chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
-			       &chip->master_volume->id);
+		key = KEY_VOLUMEUP;
 		break;
 	case 0x66:
 		/* counters decreased by 1 -> volume down */
-		if ((val & 0x7f) < 0x1f)
-			val++;
-		if ((val & 0x7f00) < 0x1f00)
-			val += 0x0100;
-		chip->ac97->regs[AC97_MASTER_VOL] = val;
-		outw(val, chip->iobase + CODEC_DATA);
-		outb(AC97_MASTER_VOL, chip->iobase + CODEC_COMMAND);
-		snd_ctl_notify(chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
-			       &chip->master_volume->id);
+		key = KEY_VOLUMEDOWN;
 		break;
 	}
-	spin_unlock_irqrestore(&chip->ac97_lock, flags);
+
+	if (key) {
+		input_report_key(chip->input_dev, key, 1);
+		input_sync(chip->input_dev);
+		input_report_key(chip->input_dev, key, 0);
+		input_sync(chip->input_dev);
+	}
+#endif
 }
 
 static irqreturn_t snd_m3_interrupt(int irq, void *dev_id)
@@ -1691,7 +1673,7 @@ static irqreturn_t snd_m3_interrupt(int irq, void *dev_id)
 		return IRQ_NONE;
 
 	if (status & HV_INT_PENDING)
-		tasklet_schedule(&chip->hwvol_tq);
+		snd_m3_update_hw_volume(chip);
 
 	/*
 	 * ack an assp int if its running
@@ -1957,18 +1939,14 @@ static unsigned short
 snd_m3_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
 {
 	struct snd_m3 *chip = ac97->private_data;
-	unsigned long flags;
 	unsigned short data = 0xffff;
 
 	if (snd_m3_ac97_wait(chip))
 		goto fail;
-	spin_lock_irqsave(&chip->ac97_lock, flags);
 	snd_m3_outb(chip, 0x80 | (reg & 0x7f), CODEC_COMMAND);
 	if (snd_m3_ac97_wait(chip))
-		goto fail_unlock;
+		goto fail;
 	data = snd_m3_inw(chip, CODEC_DATA);
-fail_unlock:
-	spin_unlock_irqrestore(&chip->ac97_lock, flags);
 fail:
 	return data;
 }
@@ -1977,14 +1955,11 @@ static void
 snd_m3_ac97_write(struct snd_ac97 *ac97, unsigned short reg, unsigned short val)
 {
 	struct snd_m3 *chip = ac97->private_data;
-	unsigned long flags;
 
 	if (snd_m3_ac97_wait(chip))
 		return;
-	spin_lock_irqsave(&chip->ac97_lock, flags);
 	snd_m3_outw(chip, val, CODEC_DATA);
 	snd_m3_outb(chip, reg & 0x7f, CODEC_COMMAND);
-	spin_unlock_irqrestore(&chip->ac97_lock, flags);
 }
 
 
@@ -2091,7 +2066,6 @@ static int __devinit snd_m3_mixer(struct snd_m3 *chip)
 {
 	struct snd_ac97_bus *pbus;
 	struct snd_ac97_template ac97;
-	struct snd_ctl_elem_id elem_id;
 	int err;
 	static struct snd_ac97_bus_ops ops = {
 		.write = snd_m3_ac97_write,
@@ -2111,15 +2085,6 @@ static int __devinit snd_m3_mixer(struct snd_m3 *chip)
 	schedule_timeout_uninterruptible(msecs_to_jiffies(100));
 	snd_ac97_write(chip->ac97, AC97_PCM, 0);
 
-	memset(&elem_id, 0, sizeof(elem_id));
-	elem_id.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
-	strcpy(elem_id.name, "Master Playback Switch");
-	chip->master_switch = snd_ctl_find_id(chip->card, &elem_id);
-	memset(&elem_id, 0, sizeof(elem_id));
-	elem_id.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
-	strcpy(elem_id.name, "Master Playback Volume");
-	chip->master_volume = snd_ctl_find_id(chip->card, &elem_id);
-
 	return 0;
 }
 
@@ -2398,6 +2363,11 @@ static int snd_m3_free(struct snd_m3 *chip)
 	struct m3_dma *s;
 	int i;
 
+#ifdef CONFIG_INPUT
+	if (chip->input_dev)
+		input_unregister_device(chip->input_dev);
+#endif
+
 	if (chip->substreams) {
 		spin_lock_irq(&chip->reg_lock);
 		for (i = 0; i < chip->num_substreams; i++) {
@@ -2524,6 +2494,42 @@ static int m3_resume(struct pci_dev *pci)
 }
 #endif /* CONFIG_PM */
 
+#ifdef CONFIG_INPUT
+static int __devinit snd_m3_input_register(struct snd_m3 *chip)
+{
+	struct input_dev *input_dev;
+	int err;
+
+	input_dev = input_allocate_device();
+	if (!input_dev)
+		return -ENOMEM;
+
+	snprintf(chip->phys, sizeof(chip->phys), "pci-%s/input0",
+		 pci_name(chip->pci));
+
+	input_dev->name = chip->card->driver;
+	input_dev->phys = chip->phys;
+	input_dev->id.bustype = BUS_PCI;
+	input_dev->id.vendor  = chip->pci->vendor;
+	input_dev->id.product = chip->pci->device;
+	input_dev->dev.parent = &chip->pci->dev;
+
+	input_dev->evbit[0] = BIT_MASK(EV_KEY);
+	input_dev->keybit[BIT_WORD(KEY_MUTE)] |= BIT_MASK(KEY_MUTE);
+	input_dev->keybit[BIT_WORD(KEY_VOLUMEDOWN)] |= BIT_MASK(KEY_VOLUMEDOWN);
+	input_dev->keybit[BIT_WORD(KEY_VOLUMEUP)] |= BIT_MASK(KEY_VOLUMEUP);
+
+	err = input_register_device(input_dev);
+	if (err) {
+		input_dev->dev.parent = NULL;
+		input_free_device(input_dev);
+	} else {
+		chip->input_dev = input_dev;
+	}
+
+	return err;
+}
+#endif /* CONFIG_INPUT */
 
 /*
  */
@@ -2567,7 +2573,6 @@ snd_m3_create(struct snd_card *card, struct pci_dev *pci,
 	}
 
 	spin_lock_init(&chip->reg_lock);
-	spin_lock_init(&chip->ac97_lock);
 
 	switch (pci->device) {
 	case PCI_DEVICE_ID_ESS_ALLEGRO:
@@ -2650,8 +2655,6 @@ snd_m3_create(struct snd_card *card, struct pci_dev *pci,
 
 	snd_m3_hv_init(chip);
 
-	tasklet_init(&chip->hwvol_tq, snd_m3_update_hw_volume, (unsigned long)chip);
-
 	if (request_irq(pci->irq, snd_m3_interrupt, IRQF_SHARED,
 			card->driver, chip)) {
 		snd_printk(KERN_ERR "unable to grab IRQ %d\n", pci->irq);
@@ -2682,7 +2685,16 @@ snd_m3_create(struct snd_card *card, struct pci_dev *pci,
 
 	if ((err = snd_m3_pcm(chip, 0)) < 0)
 		return err;
-    
+
+#ifdef CONFIG_INPUT
+	if (chip->hv_config & HV_CTRL_ENABLE) {
+		err = snd_m3_input_register(chip);
+		if (err)
+			snd_printk(KERN_WARNING "Input device registration "
+				"failed with error %i", err);
+	}
+#endif
+
 	snd_m3_enable_ints(chip);
 	snd_m3_assp_continue(chip);
 
-- 
1.7.0.1



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