commit 6f0de3ce068e48b033b5e4d0822b47218e9d206c
author Clemens Ladisch <clemens@ladisch.de> Mon Sep 28 11:18:45 2009 +0200
committer Takashi Iwai <tiwai@suse.de> Mon Sep 28 11:54:29 2009 +0200
tree 6e4e9c054a867e5deee94df181701dedc99e4275
parent dc0adf48daa81b05765d3c5ebab76321f77e9d21

sound: oxygen: cache codec registers

Keep a cache of codec registers to avoid unnecessary writes.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/oxygen/hifier.c

diff --git a/sound/pci/oxygen/hifier.c b/sound/pci/oxygen/hifier.c
index 19e9e01..2079c10 100644
--- a/sound/pci/oxygen/hifier.c
+++ b/sound/pci/oxygen/hifier.c
@@ -57,23 +57,28 @@
 MODULE_DEVICE_TABLE(pci, hifier_ids);
 
 struct hifier_data {
-	u8 ak4396_ctl2;
+	u8 ak4396_regs[5];
 };
 
 static void ak4396_write(struct oxygen *chip, u8 reg, u8 value)
 {
+	struct hifier_data *data = chip->model_data;
+
 	oxygen_write_spi(chip, OXYGEN_SPI_TRIGGER  |
 			 OXYGEN_SPI_DATA_LENGTH_2 |
 			 OXYGEN_SPI_CLOCK_160 |
 			 (0 << OXYGEN_SPI_CODEC_SHIFT) |
 			 OXYGEN_SPI_CEN_LATCH_CLOCK_HI,
 			 AK4396_WRITE | (reg << 8) | value);
+	data->ak4396_regs[reg] = value;
 }
 
-static void update_ak4396_volume(struct oxygen *chip)
+static void ak4396_write_cached(struct oxygen *chip, u8 reg, u8 value)
 {
-	ak4396_write(chip, AK4396_LCH_ATT, chip->dac_volume[0]);
-	ak4396_write(chip, AK4396_RCH_ATT, chip->dac_volume[1]);
+	struct hifier_data *data = chip->model_data;
+
+	if (value != data->ak4396_regs[reg])
+		ak4396_write(chip, reg, value);
 }
 
 static void hifier_registers_init(struct oxygen *chip)
@@ -81,16 +86,19 @@
 	struct hifier_data *data = chip->model_data;
 
 	ak4396_write(chip, AK4396_CONTROL_1, AK4396_DIF_24_MSB | AK4396_RSTN);
-	ak4396_write(chip, AK4396_CONTROL_2, data->ak4396_ctl2);
+	ak4396_write(chip, AK4396_CONTROL_2,
+		     data->ak4396_regs[AK4396_CONTROL_2]);
 	ak4396_write(chip, AK4396_CONTROL_3, AK4396_PCM);
-	update_ak4396_volume(chip);
+	ak4396_write(chip, AK4396_LCH_ATT, chip->dac_volume[0]);
+	ak4396_write(chip, AK4396_RCH_ATT, chip->dac_volume[1]);
 }
 
 static void hifier_init(struct oxygen *chip)
 {
 	struct hifier_data *data = chip->model_data;
 
-	data->ak4396_ctl2 = AK4396_SMUTE | AK4396_DEM_OFF | AK4396_DFS_NORMAL;
+	data->ak4396_regs[AK4396_CONTROL_2] =
+		AK4396_SMUTE | AK4396_DEM_OFF | AK4396_DFS_NORMAL;
 	hifier_registers_init(chip);
 
 	snd_component_add(chip->card, "AK4396");
@@ -112,20 +120,29 @@
 	struct hifier_data *data = chip->model_data;
 	u8 value;
 
-	value = data->ak4396_ctl2 & ~AK4396_DFS_MASK;
+	value = data->ak4396_regs[AK4396_CONTROL_2] & ~AK4396_DFS_MASK;
 	if (params_rate(params) <= 54000)
 		value |= AK4396_DFS_NORMAL;
 	else if (params_rate(params) <= 108000)
 		value |= AK4396_DFS_DOUBLE;
 	else
 		value |= AK4396_DFS_QUAD;
-	data->ak4396_ctl2 = value;
 
 	msleep(1); /* wait for the new MCLK to become stable */
 
-	ak4396_write(chip, AK4396_CONTROL_1, AK4396_DIF_24_MSB);
-	ak4396_write(chip, AK4396_CONTROL_2, value);
-	ak4396_write(chip, AK4396_CONTROL_1, AK4396_DIF_24_MSB | AK4396_RSTN);
+	if (value != data->ak4396_regs[AK4396_CONTROL_2]) {
+		ak4396_write(chip, AK4396_CONTROL_1,
+			     AK4396_DIF_24_MSB);
+		ak4396_write(chip, AK4396_CONTROL_2, value);
+		ak4396_write(chip, AK4396_CONTROL_1,
+			     AK4396_DIF_24_MSB | AK4396_RSTN);
+	}
+}
+
+static void update_ak4396_volume(struct oxygen *chip)
+{
+	ak4396_write_cached(chip, AK4396_LCH_ATT, chip->dac_volume[0]);
+	ak4396_write_cached(chip, AK4396_RCH_ATT, chip->dac_volume[1]);
 }
 
 static void update_ak4396_mute(struct oxygen *chip)
@@ -133,11 +150,10 @@
 	struct hifier_data *data = chip->model_data;
 	u8 value;
 
-	value = data->ak4396_ctl2 & ~AK4396_SMUTE;
+	value = data->ak4396_regs[AK4396_CONTROL_2] & ~AK4396_SMUTE;
 	if (chip->dac_mute)
 		value |= AK4396_SMUTE;
-	data->ak4396_ctl2 = value;
-	ak4396_write(chip, AK4396_CONTROL_2, value);
+	ak4396_write_cached(chip, AK4396_CONTROL_2, value);
 }
 
 static void set_cs5340_params(struct oxygen *chip,