[PATCH 3/5] media: i2c: it6625: decode audio status fields with FIELD_GET()
From: Hermes Wu via B4 Relay
Date: Tue Nov 03 2026 - 01:55:49 EST
From: Hermes Wu <Hermes.wu@xxxxxxxxxx>
The sampling-rate control compares the whole HDMI_AUDIO_INFO1 byte
against the AUD_FS code table, although AUD_FS occupies only bits
[5:0]. Any set upper bit makes every rate read back as 0.
Describe the audio registers with GENMASK() fields and decode them with
FIELD_GET(). Collect the audio status in one helper that runs under
it6625_lock: it reads RX_STATUS once, for both the video-stable and the
audio-present bits, and reads the read-only stream description in
0x6B-0x6E as a single 4-byte transfer only while audio is present. Both
audio controls are then fed from that one sample.
Drop the 0x6E alignment/delay/polarity/shift defines; they were unused,
and the audio output framing is fixed by the firmware.
Apart from masking AUD_FS, the controls behave as before: the rate
reads 0 when there is no stable signal, no audio, an unknown code or a
read error, and the present control follows the audio-present bit.
Signed-off-by: Hermes Wu <Hermes.wu@xxxxxxxxxx>
---
drivers/media/i2c/it6625.c | 206 +++++++++++++++++++++++++++++----------------
1 file changed, 132 insertions(+), 74 deletions(-)
diff --git a/drivers/media/i2c/it6625.c b/drivers/media/i2c/it6625.c
index b74df9dbf8c2cab7461c69bc0f926141ed7a506c..6f12a0e7601784e5b4ce2b395ad58a0dee335f27 100644
--- a/drivers/media/i2c/it6625.c
+++ b/drivers/media/i2c/it6625.c
@@ -83,25 +83,34 @@ MODULE_PARM_DESC(debug, "debug level (0-3)");
#define REG_HDMI_VIDEO_INFO 0x6A
#define B_COLOR_MODE BIT(0)
#define B_COLOR_DEPTH BIT(4)
+/*
+ * 0x6B-0x6E describe the decoded HDMI audio stream that the firmware passes
+ * through to the audio output. They are read-only and only meaningful while
+ * REG_RX_STATUS reports audio present.
+ */
#define REG_HDMI_AUDIO_INFO1 0x6B
-#define B_AUD_FS BIT(0)
+#define M_AUD_FS GENMASK(5, 0)
#define REG_HDMI_AUDIO_INFO2 0x6C
-#define B_AUD_CH BIT(0)
-#define B_AUD_WL BIT(4)
+#define M_AUD_CH GENMASK(3, 0)
+#define M_AUD_WL GENMASK(7, 4)
#define REG_HDMI_AUDIO_INFO3 0x6D
-#define B_AUD_TYPE BIT(0)
+#define M_AUD_TYPE GENMASK(1, 0)
+#define AUD_TYPE_LPCM 0
#define B_AUD_MS BIT(2)
#define B_AUD_3D BIT(3)
#define REG_AUDIO_FMT 0x6E
-#define B_I2S_WL BIT(0)
-#define B_I2S_ALN BIT(2)
-#define B_I2S_DLY BIT(3)
-#define B_I2S_LR BIT(4)
-#define B_I2S_SFT BIT(5)
-#define B_AUD_OUT_IF BIT(6)
+#define M_I2S_WL GENMASK(1, 0)
+#define I2S_WL_16BIT 0
+#define I2S_WL_18BIT 1
+#define I2S_WL_20BIT 2
+#define I2S_WL_24BIT 3
+#define M_AUD_OUT_IF GENMASK(7, 6)
+#define AUD_OUT_IF_I2S 0
+
+#define AUDIO_INFO_LEN 4
#define REG_IF_LATCH_HB 0x6F
#define REG_IF_DATA 0x70
@@ -249,6 +258,28 @@ enum it6625_chip_type {
IT6626_CHIP = 1,
};
+/* decoded 0x6B-0x6E: the HDMI audio stream passed through to the output */
+struct it6625_audio_stream {
+ u8 fs_code;
+ u8 channels;
+ u8 type;
+ bool multi_stream;
+ bool is_3d;
+ u8 i2s_wl;
+ u8 out_if;
+};
+
+struct it6625_audio_info {
+ /* false if any status read failed */
+ bool read_ok;
+ /* REG_RX_STATUS */
+ bool vid_stable;
+ bool present;
+ bool avmute;
+ /* only refreshed while present */
+ struct it6625_audio_stream stream;
+};
+
struct it6625 {
struct device *dev;
struct i2c_client *i2c_client;
@@ -584,61 +615,94 @@ static inline bool no_signal(struct it6625 *it6625)
return val < 0 ? true : !(val & B_RX_STABLE);
}
-static inline bool audio_present(struct it6625 *it6625)
+static const struct it6625_audio_rate {
+ u8 fs_code;
+ u32 rate;
+} it6625_audio_rates[] = {
+ { AUD32K, 32000 },
+ { AUD44K, 44100 },
+ { AUD48K, 48000 },
+ { AUD64K, 64000 },
+ { AUD88K, 88200 },
+ { AUD96K, 96000 },
+
+ { AUD128K, 128000 },
+ { AUD176K, 176400 },
+ { AUD192K, 192000 },
+ { AUD256K, 256000 },
+ { AUD352K, 352800 },
+ { AUD384K, 384000 },
+
+ { AUD512K, 512000 },
+ { AUD705K, 705600 },
+ { AUD768K, 768000 },
+ { AUD1024K, 1024000 },
+ { AUD1411K, 1411200 },
+ { AUD1536K, 1536000 },
+};
+
+/* returns 0 for an unknown sampling-frequency code */
+static u32 it6625_audio_fs_to_rate(u8 fs_code)
+{
+ for (unsigned int i = 0; i < ARRAY_SIZE(it6625_audio_rates); i++) {
+ if (it6625_audio_rates[i].fs_code == fs_code)
+ return it6625_audio_rates[i].rate;
+ }
+
+ return 0;
+}
+
+/*
+ * Sample the audio status. REG_RX_STATUS is always read; the stream
+ * description in 0x6B-0x6E is only read while audio is present, otherwise
+ * info->stream is left untouched. read_ok is false if any read failed.
+ */
+static void it6625_read_audio_info(struct it6625 *it6625,
+ struct it6625_audio_info *info)
{
+ u8 buf[AUDIO_INFO_LEN];
int val;
- val = it6625_read_byte(it6625, REG_RX_STATUS);
- return val < 0 ? false : val & B_RX_AUD_ON;
-}
-
-static int get_audio_sampling_rate(struct it6625 *it6625)
-{
- static const struct fs_id_map {
- u8 fs_id;
- u32 freq;
- } s_fsid_map[] = {
- { AUD32K, 32000 },
- { AUD44K, 44100 },
- { AUD48K, 48000 },
- { AUD64K, 64000 },
- { AUD88K, 88200 },
- { AUD96K, 96000 },
-
- { AUD128K, 128000 },
- { AUD176K, 176400 },
- { AUD192K, 192000 },
- { AUD256K, 256000 },
- { AUD352K, 352800 },
- { AUD384K, 384000 },
-
- { AUD512K, 512000 },
- { AUD705K, 705600 },
- { AUD768K, 768000 },
- { AUD1024K, 1024000 },
- { AUD1411K, 1411200 },
- { AUD1536K, 1536000 },
- };
- int fs_id;
- int i, freq = 0;
+ lockdep_assert_held(&it6625->it6625_lock);
- if (no_signal(it6625) || !audio_present(it6625))
- return 0;
+ val = it6625_read_byte(it6625, REG_RX_STATUS);
+ if (val < 0) {
+ info->read_ok = false;
+ info->vid_stable = false;
+ info->present = false;
+ info->avmute = false;
+ return;
+ }
- guard(mutex)(&it6625->it6625_lock);
+ info->read_ok = true;
+ info->vid_stable = val & B_RX_STABLE;
+ info->present = val & B_RX_AUD_ON;
+ info->avmute = val & B_RX_AVMUTE;
- fs_id = it6625_read_byte(it6625, REG_HDMI_AUDIO_INFO1);
- if (fs_id < 0)
- return 0;
+ if (!info->present)
+ return;
- for (i = 0; i < ARRAY_SIZE(s_fsid_map); i++) {
- if (s_fsid_map[i].fs_id == fs_id) {
- freq = s_fsid_map[i].freq;
- break;
- }
+ if (it6625_read_bytes(it6625, REG_HDMI_AUDIO_INFO1, buf, sizeof(buf))) {
+ info->read_ok = false;
+ return;
}
- return freq;
+ info->stream.fs_code = FIELD_GET(M_AUD_FS, buf[0]);
+ info->stream.channels = FIELD_GET(M_AUD_CH, buf[1]);
+ info->stream.type = FIELD_GET(M_AUD_TYPE, buf[2]);
+ info->stream.multi_stream = buf[2] & B_AUD_MS;
+ info->stream.is_3d = buf[2] & B_AUD_3D;
+ info->stream.i2s_wl = FIELD_GET(M_I2S_WL, buf[3]);
+ info->stream.out_if = FIELD_GET(M_AUD_OUT_IF, buf[3]);
+}
+
+/* sampling rate for the V4L2 control: 0 means unavailable */
+static u32 it6625_audio_info_rate(const struct it6625_audio_info *info)
+{
+ if (!info->read_ok || !info->vid_stable || !info->present)
+ return 0;
+
+ return it6625_audio_fs_to_rate(info->stream.fs_code);
}
static u64 it6625_get_pclk(struct it6625 *it6625)
@@ -888,20 +952,21 @@ static int it6625_s_ctrl_detect_hdmi_5v(struct v4l2_subdev *sd)
hdmi_5v_power_present(it6625));
}
-static int it6625_s_ctrl_audio_sampling_rate(struct v4l2_subdev *sd)
+static int it6625_s_ctrl_audio(struct v4l2_subdev *sd)
{
struct it6625 *it6625 = sd_to_6625(sd);
+ struct it6625_audio_info info = {};
+ int ret;
- return v4l2_ctrl_s_ctrl(it6625->ctrl_audio_sampling_rate,
- get_audio_sampling_rate(it6625));
-}
+ scoped_guard(mutex, &it6625->it6625_lock)
+ it6625_read_audio_info(it6625, &info);
-static int it6625_s_ctrl_audio_present(struct v4l2_subdev *sd)
-{
- struct it6625 *it6625 = sd_to_6625(sd);
+ ret = v4l2_ctrl_s_ctrl(it6625->ctrl_audio_sampling_rate,
+ it6625_audio_info_rate(&info));
+ if (ret)
+ return ret;
- return v4l2_ctrl_s_ctrl(it6625->ctrl_audio_present,
- audio_present(it6625));
+ return v4l2_ctrl_s_ctrl(it6625->ctrl_audio_present, info.present);
}
static int it6625_v4l2_sd_ctrl_update(struct v4l2_subdev *sd)
@@ -912,11 +977,7 @@ static int it6625_v4l2_sd_ctrl_update(struct v4l2_subdev *sd)
if (ret)
return ret;
- ret = it6625_s_ctrl_audio_sampling_rate(sd);
- if (ret)
- return ret;
-
- return it6625_s_ctrl_audio_present(sd);
+ return it6625_s_ctrl_audio(sd);
}
static int it6625_enable_stream_locked(struct it6625 *it6625, bool enable)
@@ -1165,10 +1226,7 @@ static void it6625_irq_format_change(struct it6625 *it6625)
static void it6625_irq_hdmi_audio_change(struct it6625 *it6625)
{
- struct v4l2_subdev *sd = &it6625->sd;
-
- it6625_s_ctrl_audio_sampling_rate(sd);
- it6625_s_ctrl_audio_present(sd);
+ it6625_s_ctrl_audio(&it6625->sd);
}
static void it6625_get_timings(struct it6625 *it6625,
--
2.34.1