ALSA: oxygen: Xonar DG(X): add new CS4245 SPI functions

Add the new SPI write and read functions. The SPI read function
is used for creating initial registers dump and may be used for
debugging purposes. SPI operations are cached, so there is a new
function to manage the cache (shadow). I have to remove
the shift from the CS4245_SPI_* constants, since when
we are performing the reading, we need to shift by 8 instead
of 16.

Signed-off-by: Roman Volkov <v1ron@mail.ru>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
diff --git a/sound/pci/oxygen/xonar_dg.c b/sound/pci/oxygen/xonar_dg.c
index c175720..2518c61 100644
--- a/sound/pci/oxygen/xonar_dg.c
+++ b/sound/pci/oxygen/xonar_dg.c
@@ -64,6 +64,65 @@
 #include "xonar_dg.h"
 #include "cs4245.h"
 
+int cs4245_write_spi(struct oxygen *chip, u8 reg)
+{
+	struct dg *data = chip->model_data;
+	unsigned int packet;
+
+	packet = reg << 8;
+	packet |= (CS4245_SPI_ADDRESS | CS4245_SPI_WRITE) << 16;
+	packet |= data->cs4245_shadow[reg];
+
+	return oxygen_write_spi(chip, OXYGEN_SPI_TRIGGER |
+				OXYGEN_SPI_DATA_LENGTH_3 |
+				OXYGEN_SPI_CLOCK_1280 |
+				(0 << OXYGEN_SPI_CODEC_SHIFT) |
+				OXYGEN_SPI_CEN_LATCH_CLOCK_HI,
+				packet);
+}
+
+int cs4245_read_spi(struct oxygen *chip, u8 addr)
+{
+	struct dg *data = chip->model_data;
+	int ret;
+
+	ret = oxygen_write_spi(chip, OXYGEN_SPI_TRIGGER |
+		OXYGEN_SPI_DATA_LENGTH_2 |
+		OXYGEN_SPI_CEN_LATCH_CLOCK_HI |
+		OXYGEN_SPI_CLOCK_1280 | (0 << OXYGEN_SPI_CODEC_SHIFT),
+		((CS4245_SPI_ADDRESS | CS4245_SPI_WRITE) << 8) | addr);
+	if (ret < 0)
+		return ret;
+
+	ret = oxygen_write_spi(chip, OXYGEN_SPI_TRIGGER |
+		OXYGEN_SPI_DATA_LENGTH_2 |
+		OXYGEN_SPI_CEN_LATCH_CLOCK_HI |
+		OXYGEN_SPI_CLOCK_1280 | (0 << OXYGEN_SPI_CODEC_SHIFT),
+		(CS4245_SPI_ADDRESS | CS4245_SPI_READ) << 8);
+	if (ret < 0)
+		return ret;
+
+	data->cs4245_shadow[addr] = oxygen_read8(chip, OXYGEN_SPI_DATA1);
+
+	return 0;
+}
+
+int cs4245_shadow_control(struct oxygen *chip, enum cs4245_shadow_operation op)
+{
+	struct dg *data = chip->model_data;
+	unsigned char addr;
+	int ret;
+
+	for (addr = 1; addr < ARRAY_SIZE(data->cs4245_shadow); addr++) {
+		ret = (op == CS4245_SAVE_TO_SHADOW ?
+			cs4245_read_spi(chip, addr) :
+			cs4245_write_spi(chip, addr));
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
 static void cs4245_write(struct oxygen *chip, unsigned int reg, u8 value)
 {
 	struct dg *data = chip->model_data;
@@ -73,8 +132,8 @@
 			 OXYGEN_SPI_CLOCK_1280 |
 			 (0 << OXYGEN_SPI_CODEC_SHIFT) |
 			 OXYGEN_SPI_CEN_LATCH_CLOCK_HI,
-			 CS4245_SPI_ADDRESS |
-			 CS4245_SPI_WRITE |
+			 CS4245_SPI_ADDRESS_S |
+			 CS4245_SPI_WRITE_S |
 			 (reg << 8) | value);
 	data->cs4245_regs[reg] = value;
 }