ALSA: emu10k1: query rate of external clock sources on E-MU cards

The value isn't used yet; the subsequent commits will do that.

This ignores the existence of rates above 48 kHz, which is fine, as the
hardware will just switch to the fallback clock source when fed with a
rate which is incompatible with the base clock multiplier, which
currently is always x1.

The sample rate display in /proc spdif-in is adjusted to reflect our
understanding of the input rates.

This is tested only with an 0404b card without sync card, so there is a
lot of room for improvement.

Signed-off-by: Oswald Buddenhagen <[e-mail]>

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

include/sound/emu10k1.h

···
 #define EMU_DOCK_BOARD_ID0		0x00	/* ID bit 0 */
 #define EMU_DOCK_BOARD_ID1		0x03	/* ID bit 1 */
 
+// The actual code disagrees about the bit width of the registers -
+// the formula used is freq = 0x1770000 / (((X_HI << 5) | X_LO) + 1)
+
 #define EMU_HANA_WC_SPDIF_HI	0x28	/* 0xxxxxx  6 bit  SPDIF IN Word clock, upper 6 bits */
 #define EMU_HANA_WC_SPDIF_LO	0x29	/* 0xxxxxx  6 bit  SPDIF IN Word clock, lower 6 bits */
 
···
 	unsigned int adc_pads; /* bit mask */
 	unsigned int dac_pads; /* bit mask */
 	unsigned int wclock;  /* Cached register value */
+	unsigned int word_clock;  /* Cached effective value */
 	unsigned int clock_source;
 	unsigned int clock_fallback;
 	unsigned int optical_in; /* 0:SPDIF, 1:ADAT */
···
 void snd_emu1010_fpga_read(struct snd_emu10k1 *emu, u32 reg, u32 *value);
 void snd_emu1010_fpga_link_dst_src_write(struct snd_emu10k1 *emu, u32 dst, u32 src);
 u32 snd_emu1010_fpga_link_dst_src_read(struct snd_emu10k1 *emu, u32 dst);
+int snd_emu1010_get_raw_rate(struct snd_emu10k1 *emu, u8 src);
 void snd_emu1010_update_clock(struct snd_emu10k1 *emu);
 unsigned int snd_emu10k1_efx_read(struct snd_emu10k1 *emu, unsigned int pc);
 void snd_emu10k1_intr_enable(struct snd_emu10k1 *emu, unsigned int intrenb);

sound/pci/emu10k1/emuproc.c

···
 	struct snd_emu10k1 *emu = entry->private_data;
 	u32 value;
 	u32 value2;
-	u32 rate;
 
 	if (emu->card_capabilities->emu_model) {
-		if (!emu->card_capabilities->no_adat) {
-			snd_emu1010_fpga_read(emu, 0x38, &value);
-			if ((value & 0x1) == 0) {
-				snd_emu1010_fpga_read(emu, 0x2a, &value);
-				snd_emu1010_fpga_read(emu, 0x2b, &value2);
-				rate = 0x1770000 / (((value << 5) | value2)+1);
-				snd_iprintf(buffer, "ADAT Locked : %u\n", rate);
-			} else {
-				snd_iprintf(buffer, "ADAT Unlocked\n");
-			}
+		// This represents the S/PDIF lock status on 0404b, which is
+		// kinda weird and unhelpful, because monitoring it via IRQ is
+		// impractical (one gets an IRQ flood as long as it is desynced).
+		snd_emu1010_fpga_read(emu, EMU_HANA_IRQ_STATUS, &value);
+		snd_iprintf(buffer, "Lock status 1: %#x\n", value & 0x10);
+
+		// Bit 0x1 in LO being 0 is supposedly for ADAT lock.
+		// The registers are always all zero on 0404b.
+		snd_emu1010_fpga_read(emu, EMU_HANA_LOCK_STS_LO, &value);
+		snd_emu1010_fpga_read(emu, EMU_HANA_LOCK_STS_HI, &value2);
+		snd_iprintf(buffer, "Lock status 2: %#x %#x\n", value, value2);
+
+		snd_iprintf(buffer, "S/PDIF rate: %dHz\n",
+			    snd_emu1010_get_raw_rate(emu, EMU_HANA_WCLOCK_HANA_SPDIF_IN));
+		if (emu->card_capabilities->emu_model != EMU_MODEL_EMU0404) {
+			snd_iprintf(buffer, "ADAT rate: %dHz\n",
+				    snd_emu1010_get_raw_rate(emu, EMU_HANA_WCLOCK_HANA_ADAT_IN));
+			snd_iprintf(buffer, "Dock rate: %dHz\n",
+				    snd_emu1010_get_raw_rate(emu, EMU_HANA_WCLOCK_2ND_HANA));
 		}
-		snd_emu1010_fpga_read(emu, 0x20, &value);
-		if ((value & 0x4) == 0) {
-			snd_emu1010_fpga_read(emu, 0x28, &value);
-			snd_emu1010_fpga_read(emu, 0x29, &value2);
-			rate = 0x1770000 / (((value << 5) | value2)+1);	
-			snd_iprintf(buffer, "SPDIF Locked : %d\n", rate);
-		} else {
-			snd_iprintf(buffer, "SPDIF Unlocked\n");
-		}
+		if (emu->card_capabilities->emu_model == EMU_MODEL_EMU0404 ||
+		    emu->card_capabilities->emu_model == EMU_MODEL_EMU1010)
+			snd_iprintf(buffer, "BNC rate: %dHz\n",
+				    snd_emu1010_get_raw_rate(emu, EMU_HANA_WCLOCK_SYNC_BNC));
 	} else {
 		snd_emu10k1_proc_spdif_status(emu, buffer, "CD-ROM S/PDIF In", CDCS, CDSRCS);
 		snd_emu10k1_proc_spdif_status(emu, buffer, "Optical or Coax S/PDIF In", GPSCS, GPSRCS);

sound/pci/emu10k1/io.c

···
 	return (hi << 8) | lo;
 }
 
+int snd_emu1010_get_raw_rate(struct snd_emu10k1 *emu, u8 src)
+{
+	u32 reg_lo, reg_hi, value, value2;
+
+	switch (src) {
+	case EMU_HANA_WCLOCK_HANA_SPDIF_IN:
+		snd_emu1010_fpga_read(emu, EMU_HANA_SPDIF_MODE, &value);
+		if (value & EMU_HANA_SPDIF_MODE_RX_INVALID)
+			return 0;
+		reg_lo = EMU_HANA_WC_SPDIF_LO;
+		reg_hi = EMU_HANA_WC_SPDIF_HI;
+		break;
+	case EMU_HANA_WCLOCK_HANA_ADAT_IN:
+		reg_lo = EMU_HANA_WC_ADAT_LO;
+		reg_hi = EMU_HANA_WC_ADAT_HI;
+		break;
+	case EMU_HANA_WCLOCK_SYNC_BNC:
+		reg_lo = EMU_HANA_WC_BNC_LO;
+		reg_hi = EMU_HANA_WC_BNC_HI;
+		break;
+	case EMU_HANA_WCLOCK_2ND_HANA:
+		reg_lo = EMU_HANA2_WC_SPDIF_LO;
+		reg_hi = EMU_HANA2_WC_SPDIF_HI;
+		break;
+	default:
+		return 0;
+	}
+	snd_emu1010_fpga_read(emu, reg_hi, &value);
+	snd_emu1010_fpga_read(emu, reg_lo, &value2);
+	// FIXME: The /4 is valid for 0404b, but contradicts all other info.
+	return 0x1770000 / 4 / (((value << 5) | value2) + 1);
+}
+
 void snd_emu1010_update_clock(struct snd_emu10k1 *emu)
 {
+	int clock;
 	u32 leds;
 
 	switch (emu->emu1010.wclock) {
 	case EMU_HANA_WCLOCK_INT_44_1K | EMU_HANA_WCLOCK_1X:
+		clock = 44100;
 		leds = EMU_HANA_DOCK_LEDS_2_44K;
 		break;
 	case EMU_HANA_WCLOCK_INT_48K | EMU_HANA_WCLOCK_1X:
+		clock = 48000;
 		leds = EMU_HANA_DOCK_LEDS_2_48K;
 		break;
 	default:
-		leds = EMU_HANA_DOCK_LEDS_2_EXT;
+		clock = snd_emu1010_get_raw_rate(
+				emu, emu->emu1010.wclock & EMU_HANA_WCLOCK_SRC_MASK);
+		// The raw rate reading is rather coarse (it cannot accurately
+		// represent 44.1 kHz) and fluctuates slightly. Luckily, the
+		// clock comes from digital inputs, which use standardized rates.
+		// So we round to the closest standard rate and ignore discrepancies.
+		if (clock < 46000) {
+			clock = 44100;
+			leds = EMU_HANA_DOCK_LEDS_2_EXT | EMU_HANA_DOCK_LEDS_2_44K;
+		} else {
+			clock = 48000;
+			leds = EMU_HANA_DOCK_LEDS_2_EXT | EMU_HANA_DOCK_LEDS_2_48K;
+		}
 		break;
 	}
+	emu->emu1010.word_clock = clock;
 
 	// FIXME: this should probably represent the AND of all currently
 	// used sources' lock status. But we don't know how to get that ...