[alsa-devel] [PATCH] sun-cs4231: mce_down cleanup after ad1848

[Krzysztof Helt]

From: Krzysztof Helt <krzysztof.h1 at wp.pl>

This simplifies and fixes waiting loops of the mce_down()
function after Trent Piepho's patch for AD1848.
It also makes busy_wait() function call not atomic.

Signed-off-by: Krzysztof Helt <krzysztof.h1 at wp.pl>

---

diff -urp linux-ref/sound/sparc/cs4231.c linux-2.6.23/sound/sparc/cs4231.c
--- linux-ref/sound/sparc/cs4231.c	2007-09-19 23:31:30.603838619 +0200
+++ linux-2.6.23/sound/sparc/cs4231.c	2007-09-19 23:23:24.552140109 +0200
@@ -392,62 +392,45 @@ static void snd_cs4231_mce_up(struct snd
 
 static void snd_cs4231_mce_down(struct snd_cs4231 *chip)
 {
-	unsigned long flags;
-	int timeout;
+	unsigned long flags, timeout;
+	int reg;
 
-	spin_lock_irqsave(&chip->lock, flags);
 	snd_cs4231_busy_wait(chip);
+	spin_lock_irqsave(&chip->lock, flags);
 #ifdef CONFIG_SND_DEBUG
 	if (__cs4231_readb(chip, CS4231U(chip, REGSEL)) & CS4231_INIT)
 		snd_printdd("mce_down [%p] - auto calibration time out (0)\n",
 			    CS4231U(chip, REGSEL));
 #endif
 	chip->mce_bit &= ~CS4231_MCE;
-	timeout = __cs4231_readb(chip, CS4231U(chip, REGSEL));
-	__cs4231_writeb(chip, chip->mce_bit | (timeout & 0x1f),
+	reg = __cs4231_readb(chip, CS4231U(chip, REGSEL));
+	__cs4231_writeb(chip, chip->mce_bit | (reg & 0x1f),
 			CS4231U(chip, REGSEL));
-	if (timeout == 0x80)
-		snd_printdd("mce_down [%p]: serious init problem - codec still busy\n", chip->port);
-	if ((timeout & CS4231_MCE) == 0) {
+	if (reg == 0x80)
+		snd_printdd("mce_down [%p]: serious init problem "
+			    "- codec still busy\n", chip->port);
+	if ((reg & CS4231_MCE) == 0) {
 		spin_unlock_irqrestore(&chip->lock, flags);
 		return;
 	}
-	snd_cs4231_busy_wait(chip);
 
-	/* calibration process */
+	/*
+	 * Wait for auto-calibration (AC) process to finish, i.e. ACI to go low.
+	 */
 
-	snd_cs4231_ready(chip);
-	snd_cs4231_ready(chip);
-	if ((snd_cs4231_in(chip, CS4231_TEST_INIT) & CS4231_CALIB_IN_PROGRESS) == 0) {
-		snd_printd("cs4231_mce_down - auto calibration time out (1)\n");
+	timeout = jiffies + msecs_to_jiffies(250);
+	do {
 		spin_unlock_irqrestore(&chip->lock, flags);
-		return;
-	}
-
-	/* in 10ms increments, check condition, up to 250ms */
-	timeout = 25;
-	while (snd_cs4231_in(chip, CS4231_TEST_INIT) & CS4231_CALIB_IN_PROGRESS) {
-		spin_unlock_irqrestore(&chip->lock, flags);
-		if (--timeout < 0) {
-			snd_printk("mce_down - auto calibration time out (2)\n");
-			return;
-		}
-		msleep(10);
-		spin_lock_irqsave(&chip->lock, flags);
-	}
-
-	/* in 10ms increments, check condition, up to 100ms */
-	timeout = 10;
-	while (__cs4231_readb(chip, CS4231U(chip, REGSEL)) & CS4231_INIT) {
-		spin_unlock_irqrestore(&chip->lock, flags);
-		if (--timeout < 0) {
-			snd_printk("mce_down - auto calibration time out (3)\n");
-			return;
-		}
-		msleep(10);
+		msleep(1);
 		spin_lock_irqsave(&chip->lock, flags);
-	}
+		reg = snd_cs4231_in(chip, CS4231_TEST_INIT);
+		reg &= CS4231_CALIB_IN_PROGRESS;
+	} while (reg && time_before(jiffies, timeout));
 	spin_unlock_irqrestore(&chip->lock, flags);
+
+	if (reg)
+		snd_printk(KERN_ERR
+			   "mce_down - auto calibration time out (2)\n");
 }
 
 static void snd_cs4231_advance_dma(struct cs4231_dma_control *dma_cont,

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