ASoC: tlv320aic31xx: Add support for loading filter coefficients

The TLV320DAC3100 Audio DAC has 25 built-in digital audio processing blocks
(PRBs). Each of these PRBs has a static filter structure with programmable
coefficients. Once a PRB is selected for use by the DAC, its filter
coefficients can be configured via a dedicated set of registers.

Define a new optional firmware which can be loaded by the TLV320DAC driver.
This firmware describes a full set of filter coefficients for all blocks
used by the various PRBs.

The firmware's binary format is heavily inspired by the one used in the
peb2466 driver. It includes a version marker to allow for potential
evolutions of the format.

Note that adaptive filtering is not supported i.e. filter coefficients are
loaded once before power-on and then cannot be changed while the DAC is
powered. This is why only page A coefficients are modified. Page B
coefficients are only used for adaptive filtering.

Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
Link: https://patch.msgid.link/20240906-tlv320-filter-v1-1-6955f53ff435@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/tlv320aic31xx.c b/sound/soc/codecs/tlv320aic31xx.c
index 2f94cfda0e3302823cdc8bc89d0f96f68e9995ee..7e624c4b77b60ecd4fc36ec6b39bd067124023d5 100644 (file)
--- a/sound/soc/codecs/tlv320aic31xx.c
+++ b/sound/soc/codecs/tlv320aic31xx.c
@@ -12,6 +12,7 @@
  * and mono/stereo Class-D speaker driver.
  */
 
+#include <asm/unaligned.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/init.h>
@@ -22,6 +23,7 @@
 #include <linux/gpio/consumer.h>
 #include <linux/regulator/consumer.h>
 #include <linux/acpi.h>
+#include <linux/firmware.h>
 #include <linux/of.h>
 #include <linux/slab.h>
 #include <sound/core.h>
@@ -1638,6 +1640,98 @@ static const struct i2c_device_id aic31xx_i2c_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, aic31xx_i2c_id);
 
+static int tlv320dac3100_fw_load(struct aic31xx_priv *aic31xx,
+                                const u8 *data, size_t size)
+{
+       int ret, reg;
+       u16 val16;
+
+       /*
+        * Coefficients firmware binary structure. Multi-byte values are big-endian.
+        *
+        * @0, 16bits: Magic (0xB30C)
+        * @2, 16bits: Version (0x0100 for version 1.0)
+        * @4, 8bits: DAC Processing Block Selection
+        * @5, 62 16-bit values: Page 8 buffer A DAC programmable filter coefficients
+        * @129, 12 16-bit values: Page 9 Buffer A DAC programmable filter coefficients
+        *
+        * Filter coefficients are interpreted as two's complement values
+        * ranging from -32 768 to 32 767. For more details on filter coefficients,
+        * please refer to the TLV320DAC3100 datasheet, tables 6-120 and 6-123.
+        */
+
+       if (size != 153) {
+               dev_err(aic31xx->dev, "firmware size is %zu, expected 153 bytes\n", size);
+               return -EINVAL;
+       }
+
+       /* Check magic */
+       val16 = get_unaligned_be16(data);
+       if (val16 != 0xb30c) {
+               dev_err(aic31xx->dev, "fw magic is 0x%04x expected 0xb30c\n", val16);
+               return -EINVAL;
+       }
+       data += 2;
+
+       /* Check version */
+       val16 = get_unaligned_be16(data);
+       if (val16 != 0x0100) {
+               dev_err(aic31xx->dev, "invalid firmware version 0x%04x! expected 1", val16);
+               return -EINVAL;
+       }
+       data += 2;
+
+       ret = regmap_write(aic31xx->regmap, AIC31XX_DACPRB, *data);
+       if (ret) {
+               dev_err(aic31xx->dev, "failed to write PRB index: err %d\n", ret);
+               return ret;
+       }
+       data += 1;
+
+       /* Page 8 Buffer A coefficients */
+       for (reg = 2; reg < 126; reg++) {
+               ret = regmap_write(aic31xx->regmap, AIC31XX_REG(8, reg), *data);
+               if (ret) {
+                       dev_err(aic31xx->dev,
+                               "failed to write page 8 filter coefficient %d: err %d\n", reg, ret);
+                       return ret;
+               }
+               data++;
+       }
+
+       /* Page 9 Buffer A coefficients */
+       for (reg = 2; reg < 26; reg++) {
+               ret = regmap_write(aic31xx->regmap, AIC31XX_REG(9, reg), *data);
+               if (ret) {
+                       dev_err(aic31xx->dev,
+                               "failed to write page 9 filter coefficient %d: err %d\n", reg, ret);
+                       return ret;
+               }
+               data++;
+       }
+
+       dev_info(aic31xx->dev, "done loading DAC filter coefficients\n");
+
+       return ret;
+}
+
+static int tlv320dac3100_load_coeffs(struct aic31xx_priv *aic31xx,
+                                    const char *fw_name)
+{
+       const struct firmware *fw;
+       int ret;
+
+       ret = request_firmware(&fw, fw_name, aic31xx->dev);
+       if (ret)
+               return ret;
+
+       ret = tlv320dac3100_fw_load(aic31xx, fw->data, fw->size);
+
+       release_firmware(fw);
+
+       return ret;
+}
+
 static int aic31xx_i2c_probe(struct i2c_client *i2c)
 {
        struct aic31xx_priv *aic31xx;
@@ -1727,6 +1821,12 @@ static int aic31xx_i2c_probe(struct i2c_client *i2c)
                }
        }
 
+       if (aic31xx->codec_type == DAC3100) {
+               ret = tlv320dac3100_load_coeffs(aic31xx, "tlv320dac3100-coeffs.bin");
+               if (ret)
+                       dev_warn(aic31xx->dev, "Did not load any filter coefficients\n");
+       }
+
        if (aic31xx->codec_type & DAC31XX_BIT)
                return devm_snd_soc_register_component(&i2c->dev,
                                &soc_codec_driver_aic31xx,