drivers/media/i2c/m52790.c

Source file repositories/reference/linux-study-clean/drivers/media/i2c/m52790.c

File Facts

System
Linux kernel
Corpus path
drivers/media/i2c/m52790.c
Extension
.c
Size
4586 bytes
Lines
181
Domain
Driver Families
Bucket
drivers/media
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct m52790_state {
	struct v4l2_subdev sd;
	u16 input;
	u16 output;
};

static inline struct m52790_state *to_state(struct v4l2_subdev *sd)
{
	return container_of(sd, struct m52790_state, sd);
}

/* ----------------------------------------------------------------------- */

static int m52790_write(struct v4l2_subdev *sd)
{
	struct m52790_state *state = to_state(sd);
	struct i2c_client *client = v4l2_get_subdevdata(sd);

	u8 sw1 = (state->input | state->output) & 0xff;
	u8 sw2 = (state->input | state->output) >> 8;

	return i2c_smbus_write_byte_data(client, sw1, sw2);
}

/* Note: audio and video are linked and cannot be switched separately.
   So audio and video routing commands are identical for this chip.
   In theory the video amplifier and audio modes could be handled
   separately for the output, but that seems to be overkill right now.
   The same holds for implementing an audio mute control, this is now
   part of the audio output routing. The normal case is that another
   chip takes care of the actual muting so making it part of the
   output routing seems to be the right thing to do for now. */
static int m52790_s_routing(struct v4l2_subdev *sd,
			    u32 input, u32 output, u32 config)
{
	struct m52790_state *state = to_state(sd);

	state->input = input;
	state->output = output;
	m52790_write(sd);
	return 0;
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int m52790_g_register(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg)
{
	struct m52790_state *state = to_state(sd);

	if (reg->reg != 0)
		return -EINVAL;
	reg->size = 1;
	reg->val = state->input | state->output;
	return 0;
}

static int m52790_s_register(struct v4l2_subdev *sd, const struct v4l2_dbg_register *reg)
{
	struct m52790_state *state = to_state(sd);

	if (reg->reg != 0)
		return -EINVAL;
	state->input = reg->val & 0x0303;
	state->output = reg->val & ~0x0303;
	m52790_write(sd);
	return 0;
}
#endif

static int m52790_log_status(struct v4l2_subdev *sd)
{
	struct m52790_state *state = to_state(sd);

	v4l2_info(sd, "Switch 1: %02x\n",
			(state->input | state->output) & 0xff);
	v4l2_info(sd, "Switch 2: %02x\n",
			(state->input | state->output) >> 8);
	return 0;
}

/* ----------------------------------------------------------------------- */

static const struct v4l2_subdev_core_ops m52790_core_ops = {
	.log_status = m52790_log_status,
#ifdef CONFIG_VIDEO_ADV_DEBUG
	.g_register = m52790_g_register,
	.s_register = m52790_s_register,
#endif
};

static const struct v4l2_subdev_audio_ops m52790_audio_ops = {

Annotation

Implementation Notes