drivers/media/tuners/mxl301rf.c

Source file repositories/reference/linux-study-clean/drivers/media/tuners/mxl301rf.c

File Facts

System
Linux kernel
Corpus path
drivers/media/tuners/mxl301rf.c
Extension
.c
Size
7788 bytes
Lines
339
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 mxl301rf_state {
	struct mxl301rf_config cfg;
	struct i2c_client *i2c;
};

static struct mxl301rf_state *cfg_to_state(struct mxl301rf_config *c)
{
	return container_of(c, struct mxl301rf_state, cfg);
}

static int raw_write(struct mxl301rf_state *state, const u8 *buf, int len)
{
	int ret;

	ret = i2c_master_send(state->i2c, buf, len);
	if (ret >= 0 && ret < len)
		ret = -EIO;
	return (ret == len) ? 0 : ret;
}

static int reg_write(struct mxl301rf_state *state, u8 reg, u8 val)
{
	u8 buf[2] = { reg, val };

	return raw_write(state, buf, 2);
}

static int reg_read(struct mxl301rf_state *state, u8 reg, u8 *val)
{
	u8 wbuf[2] = { 0xfb, reg };
	int ret;

	ret = raw_write(state, wbuf, sizeof(wbuf));
	if (ret == 0)
		ret = i2c_master_recv(state->i2c, val, 1);
	if (ret >= 0 && ret < 1)
		ret = -EIO;
	return (ret == 1) ? 0 : ret;
}

/* tuner_ops */

/* get RSSI and update property cache, set to *out in % */
static int mxl301rf_get_rf_strength(struct dvb_frontend *fe, u16 *out)
{
	struct mxl301rf_state *state;
	int ret;
	u8  rf_in1, rf_in2, rf_off1, rf_off2;
	u16 rf_in, rf_off;
	s64 level;
	struct dtv_fe_stats *rssi;

	rssi = &fe->dtv_property_cache.strength;
	rssi->len = 1;
	rssi->stat[0].scale = FE_SCALE_NOT_AVAILABLE;
	*out = 0;

	state = fe->tuner_priv;
	ret = reg_write(state, 0x14, 0x01);
	if (ret < 0)
		return ret;
	usleep_range(1000, 2000);

	ret = reg_read(state, 0x18, &rf_in1);
	if (ret == 0)
		ret = reg_read(state, 0x19, &rf_in2);
	if (ret == 0)
		ret = reg_read(state, 0xd6, &rf_off1);
	if (ret == 0)
		ret = reg_read(state, 0xd7, &rf_off2);
	if (ret != 0)
		return ret;

	rf_in = (rf_in2 & 0x07) << 8 | rf_in1;
	rf_off = (rf_off2 & 0x0f) << 5 | (rf_off1 >> 3);
	level = rf_in - rf_off - (113 << 3); /* x8 dBm */
	level = level * 1000 / 8;
	rssi->stat[0].svalue = level;
	rssi->stat[0].scale = FE_SCALE_DECIBEL;
	/* *out = (level - min) * 100 / (max - min) */
	*out = (rf_in - rf_off + (1 << 9) - 1) * 100 / ((5 << 9) - 2);
	return 0;
}

/* spur shift parameters */
struct shf {
	u32	freq;		/* Channel center frequency */
	u32	ofst_th;	/* Offset frequency threshold */
	u8	shf_val;	/* Spur shift value */
	u8	shf_dir;	/* Spur shift direction */

Annotation

Implementation Notes