v4.19.13 snapshot.
diff --git a/sound/pci/oxygen/oxygen_io.c b/sound/pci/oxygen/oxygen_io.c
new file mode 100644
index 0000000..c7851da
--- /dev/null
+++ b/sound/pci/oxygen/oxygen_io.c
@@ -0,0 +1,292 @@
+/*
+ * C-Media CMI8788 driver - helper functions
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ *
+ *
+ *  This driver is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License, version 2.
+ *
+ *  This driver is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this driver; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/export.h>
+#include <linux/io.h>
+#include <sound/core.h>
+#include <sound/mpu401.h>
+#include "oxygen.h"
+
+u8 oxygen_read8(struct oxygen *chip, unsigned int reg)
+{
+	return inb(chip->addr + reg);
+}
+EXPORT_SYMBOL(oxygen_read8);
+
+u16 oxygen_read16(struct oxygen *chip, unsigned int reg)
+{
+	return inw(chip->addr + reg);
+}
+EXPORT_SYMBOL(oxygen_read16);
+
+u32 oxygen_read32(struct oxygen *chip, unsigned int reg)
+{
+	return inl(chip->addr + reg);
+}
+EXPORT_SYMBOL(oxygen_read32);
+
+void oxygen_write8(struct oxygen *chip, unsigned int reg, u8 value)
+{
+	outb(value, chip->addr + reg);
+	chip->saved_registers._8[reg] = value;
+}
+EXPORT_SYMBOL(oxygen_write8);
+
+void oxygen_write16(struct oxygen *chip, unsigned int reg, u16 value)
+{
+	outw(value, chip->addr + reg);
+	chip->saved_registers._16[reg / 2] = cpu_to_le16(value);
+}
+EXPORT_SYMBOL(oxygen_write16);
+
+void oxygen_write32(struct oxygen *chip, unsigned int reg, u32 value)
+{
+	outl(value, chip->addr + reg);
+	chip->saved_registers._32[reg / 4] = cpu_to_le32(value);
+}
+EXPORT_SYMBOL(oxygen_write32);
+
+void oxygen_write8_masked(struct oxygen *chip, unsigned int reg,
+			  u8 value, u8 mask)
+{
+	u8 tmp = inb(chip->addr + reg);
+	tmp &= ~mask;
+	tmp |= value & mask;
+	outb(tmp, chip->addr + reg);
+	chip->saved_registers._8[reg] = tmp;
+}
+EXPORT_SYMBOL(oxygen_write8_masked);
+
+void oxygen_write16_masked(struct oxygen *chip, unsigned int reg,
+			   u16 value, u16 mask)
+{
+	u16 tmp = inw(chip->addr + reg);
+	tmp &= ~mask;
+	tmp |= value & mask;
+	outw(tmp, chip->addr + reg);
+	chip->saved_registers._16[reg / 2] = cpu_to_le16(tmp);
+}
+EXPORT_SYMBOL(oxygen_write16_masked);
+
+void oxygen_write32_masked(struct oxygen *chip, unsigned int reg,
+			   u32 value, u32 mask)
+{
+	u32 tmp = inl(chip->addr + reg);
+	tmp &= ~mask;
+	tmp |= value & mask;
+	outl(tmp, chip->addr + reg);
+	chip->saved_registers._32[reg / 4] = cpu_to_le32(tmp);
+}
+EXPORT_SYMBOL(oxygen_write32_masked);
+
+static int oxygen_ac97_wait(struct oxygen *chip, unsigned int mask)
+{
+	u8 status = 0;
+
+	/*
+	 * Reading the status register also clears the bits, so we have to save
+	 * the read bits in status.
+	 */
+	wait_event_timeout(chip->ac97_waitqueue,
+			   ({ status |= oxygen_read8(chip, OXYGEN_AC97_INTERRUPT_STATUS);
+			      status & mask; }),
+			   msecs_to_jiffies(1) + 1);
+	/*
+	 * Check even after a timeout because this function should not require
+	 * the AC'97 interrupt to be enabled.
+	 */
+	status |= oxygen_read8(chip, OXYGEN_AC97_INTERRUPT_STATUS);
+	return status & mask ? 0 : -EIO;
+}
+
+/*
+ * About 10% of AC'97 register reads or writes fail to complete, but even those
+ * where the controller indicates completion aren't guaranteed to have actually
+ * happened.
+ *
+ * It's hard to assign blame to either the controller or the codec because both
+ * were made by C-Media ...
+ */
+
+void oxygen_write_ac97(struct oxygen *chip, unsigned int codec,
+		       unsigned int index, u16 data)
+{
+	unsigned int count, succeeded;
+	u32 reg;
+
+	reg = data;
+	reg |= index << OXYGEN_AC97_REG_ADDR_SHIFT;
+	reg |= OXYGEN_AC97_REG_DIR_WRITE;
+	reg |= codec << OXYGEN_AC97_REG_CODEC_SHIFT;
+	succeeded = 0;
+	for (count = 5; count > 0; --count) {
+		udelay(5);
+		oxygen_write32(chip, OXYGEN_AC97_REGS, reg);
+		/* require two "completed" writes, just to be sure */
+		if (oxygen_ac97_wait(chip, OXYGEN_AC97_INT_WRITE_DONE) >= 0 &&
+		    ++succeeded >= 2) {
+			chip->saved_ac97_registers[codec][index / 2] = data;
+			return;
+		}
+	}
+	dev_err(chip->card->dev, "AC'97 write timeout\n");
+}
+EXPORT_SYMBOL(oxygen_write_ac97);
+
+u16 oxygen_read_ac97(struct oxygen *chip, unsigned int codec,
+		     unsigned int index)
+{
+	unsigned int count;
+	unsigned int last_read = UINT_MAX;
+	u32 reg;
+
+	reg = index << OXYGEN_AC97_REG_ADDR_SHIFT;
+	reg |= OXYGEN_AC97_REG_DIR_READ;
+	reg |= codec << OXYGEN_AC97_REG_CODEC_SHIFT;
+	for (count = 5; count > 0; --count) {
+		udelay(5);
+		oxygen_write32(chip, OXYGEN_AC97_REGS, reg);
+		udelay(10);
+		if (oxygen_ac97_wait(chip, OXYGEN_AC97_INT_READ_DONE) >= 0) {
+			u16 value = oxygen_read16(chip, OXYGEN_AC97_REGS);
+			/* we require two consecutive reads of the same value */
+			if (value == last_read)
+				return value;
+			last_read = value;
+			/*
+			 * Invert the register value bits to make sure that two
+			 * consecutive unsuccessful reads do not return the same
+			 * value.
+			 */
+			reg ^= 0xffff;
+		}
+	}
+	dev_err(chip->card->dev, "AC'97 read timeout on codec %u\n", codec);
+	return 0;
+}
+EXPORT_SYMBOL(oxygen_read_ac97);
+
+void oxygen_write_ac97_masked(struct oxygen *chip, unsigned int codec,
+			      unsigned int index, u16 data, u16 mask)
+{
+	u16 value = oxygen_read_ac97(chip, codec, index);
+	value &= ~mask;
+	value |= data & mask;
+	oxygen_write_ac97(chip, codec, index, value);
+}
+EXPORT_SYMBOL(oxygen_write_ac97_masked);
+
+static int oxygen_wait_spi(struct oxygen *chip)
+{
+	unsigned int count;
+
+	/*
+	 * Higher timeout to be sure: 200 us;
+	 * actual transaction should not need more than 40 us.
+	 */
+	for (count = 50; count > 0; count--) {
+		udelay(4);
+		if ((oxygen_read8(chip, OXYGEN_SPI_CONTROL) &
+						OXYGEN_SPI_BUSY) == 0)
+			return 0;
+	}
+	dev_err(chip->card->dev, "oxygen: SPI wait timeout\n");
+	return -EIO;
+}
+
+int oxygen_write_spi(struct oxygen *chip, u8 control, unsigned int data)
+{
+	/*
+	 * We need to wait AFTER initiating the SPI transaction,
+	 * otherwise read operations will not work.
+	 */
+	oxygen_write8(chip, OXYGEN_SPI_DATA1, data);
+	oxygen_write8(chip, OXYGEN_SPI_DATA2, data >> 8);
+	if (control & OXYGEN_SPI_DATA_LENGTH_3)
+		oxygen_write8(chip, OXYGEN_SPI_DATA3, data >> 16);
+	oxygen_write8(chip, OXYGEN_SPI_CONTROL, control);
+	return oxygen_wait_spi(chip);
+}
+EXPORT_SYMBOL(oxygen_write_spi);
+
+void oxygen_write_i2c(struct oxygen *chip, u8 device, u8 map, u8 data)
+{
+	/* should not need more than about 300 us */
+	msleep(1);
+
+	oxygen_write8(chip, OXYGEN_2WIRE_MAP, map);
+	oxygen_write8(chip, OXYGEN_2WIRE_DATA, data);
+	oxygen_write8(chip, OXYGEN_2WIRE_CONTROL,
+		      device | OXYGEN_2WIRE_DIR_WRITE);
+}
+EXPORT_SYMBOL(oxygen_write_i2c);
+
+static void _write_uart(struct oxygen *chip, unsigned int port, u8 data)
+{
+	if (oxygen_read8(chip, OXYGEN_MPU401 + 1) & MPU401_TX_FULL)
+		msleep(1);
+	oxygen_write8(chip, OXYGEN_MPU401 + port, data);
+}
+
+void oxygen_reset_uart(struct oxygen *chip)
+{
+	_write_uart(chip, 1, MPU401_RESET);
+	msleep(1); /* wait for ACK */
+	_write_uart(chip, 1, MPU401_ENTER_UART);
+}
+EXPORT_SYMBOL(oxygen_reset_uart);
+
+void oxygen_write_uart(struct oxygen *chip, u8 data)
+{
+	_write_uart(chip, 0, data);
+}
+EXPORT_SYMBOL(oxygen_write_uart);
+
+u16 oxygen_read_eeprom(struct oxygen *chip, unsigned int index)
+{
+	unsigned int timeout;
+
+	oxygen_write8(chip, OXYGEN_EEPROM_CONTROL,
+		      index | OXYGEN_EEPROM_DIR_READ);
+	for (timeout = 0; timeout < 100; ++timeout) {
+		udelay(1);
+		if (!(oxygen_read8(chip, OXYGEN_EEPROM_STATUS)
+		      & OXYGEN_EEPROM_BUSY))
+			break;
+	}
+	return oxygen_read16(chip, OXYGEN_EEPROM_DATA);
+}
+
+void oxygen_write_eeprom(struct oxygen *chip, unsigned int index, u16 value)
+{
+	unsigned int timeout;
+
+	oxygen_write16(chip, OXYGEN_EEPROM_DATA, value);
+	oxygen_write8(chip, OXYGEN_EEPROM_CONTROL,
+		      index | OXYGEN_EEPROM_DIR_WRITE);
+	for (timeout = 0; timeout < 10; ++timeout) {
+		msleep(1);
+		if (!(oxygen_read8(chip, OXYGEN_EEPROM_STATUS)
+		      & OXYGEN_EEPROM_BUSY))
+			return;
+	}
+	dev_err(chip->card->dev, "EEPROM write timeout\n");
+}