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>

1 files changed, 31 insertions, 15 deletions

diff --git a/sound/pci/oxygen/hifier.c b/sound/pci/oxygen/hifier.c
index 19e9e0123304..2079c100aabc 100644
--- a/sound/pci/oxygen/hifier.c
+++ b/sound/pci/oxygen/hifier.c
@@ -57,23 +57,28 @@ static struct pci_device_id hifier_ids[] __devinitdata = {
 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 @@ static void hifier_registers_init(struct oxygen *chip)
         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 @@ static void set_ak4396_params(struct oxygen *chip,
         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 @@ static void update_ak4396_mute(struct oxygen *chip)
         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,