[ALSA] ad1838/cs4231 - fix MCE timeout upon initial load

When the ad1848/cs2431 is first being initialized, auto-calibration may not
be set causing a timeout waiting for it in snd_ad1848/cs4231_mce_down().
This has no dire consequences other than an alarming printk, but since what
we need to wait for is for the calibration to _finish_, let's just check for
that instead.
The early chips need a slight delay (as commented -- 5 sample periods) to be
sure that _if_ calibration is going to happen, it has started when we check
While the CS4231A datasheet implies it'll happen immediately on downing MCE,
some testing is showing that there's a window there as well, so just do the
delay everywhere.
Thanks to Krysztof Helt for pinpointing this problem.
Signed-off-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/isa/ad1848/ad1848_lib.c

@@ -229,16 +229,15 @@ static void snd_ad1848_mce_down(struct snd_ad1848 *chip)
 		spin_unlock_irqrestore(&chip->reg_lock, flags);
 		return;
 	}
-	/* calibration process */
 
-	for (timeout = 500; timeout > 0 && (snd_ad1848_in(chip, AD1848_TEST_INIT) & AD1848_CALIB_IN_PROGRESS) == 0; timeout--);
-	if ((snd_ad1848_in(chip, AD1848_TEST_INIT) & AD1848_CALIB_IN_PROGRESS) == 0) {
-		snd_printd("mce_down - auto calibration time out (1)\n");
-		spin_unlock_irqrestore(&chip->reg_lock, flags);
-		return;
-	}
+	/*
+	 * Wait for (possible -- during init auto-calibration may not be set)
+	 * calibration process to start. Needs upto 5 sample periods on AD1848
+	 * which at the slowest possible rate of 5.5125 kHz means 907 us.
+	 */
+	msleep(1);
 #if 0
-	printk("(2) timeout = %i, jiffies = %li\n", timeout, jiffies);
+	printk("(2) jiffies = %li\n", jiffies);
 #endif
 	time = HZ / 4;
 	while (snd_ad1848_in(chip, AD1848_TEST_INIT) & AD1848_CALIB_IN_PROGRESS) {

sound/isa/cs423x/cs4231_lib.c

@@ -336,16 +336,14 @@ void snd_cs4231_mce_down(struct snd_cs4231 *chip)
 	}
 	snd_cs4231_busy_wait(chip);
 
-	/* calibration process */
-
-	for (timeout = 500; timeout > 0 && (snd_cs4231_in(chip, CS4231_TEST_INIT) & CS4231_CALIB_IN_PROGRESS) == 0; timeout--)
-		udelay(10);
-	if ((snd_cs4231_in(chip, CS4231_TEST_INIT) & CS4231_CALIB_IN_PROGRESS) == 0) {
-		snd_printd("cs4231_mce_down - auto calibration time out (1)\n");
-		return;
-	}
+	/*
+	 * Wait for (possible -- during init auto-calibration may not be set)
+	 * calibration process to start. Needs upto 5 sample periods on AD1848
+	 * which at the slowest possible rate of 5.5125 kHz means 907 us.
+	 */
+	msleep(1);
 #if 0
-	printk("(2) timeout = %i, jiffies = %li\n", timeout, jiffies);
+	printk("(2) jiffies = %li\n", jiffies);
 #endif
 	/* in 10 ms increments, check condition, up to 250 ms */
 	timeout = 25;