drivers/media/dvb-frontends/tda826x.c

Source file repositories/reference/linux-study-clean/drivers/media/dvb-frontends/tda826x.c

File Facts

System
Linux kernel
Corpus path
drivers/media/dvb-frontends/tda826x.c
Extension
.c
Size
4366 bytes
Lines
175
Domain
Driver Families
Bucket
drivers/media
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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 tda826x_priv {
	/* i2c details */
	int i2c_address;
	struct i2c_adapter *i2c;
	u8 has_loopthrough:1;
	u32 frequency;
};

static void tda826x_release(struct dvb_frontend *fe)
{
	kfree(fe->tuner_priv);
	fe->tuner_priv = NULL;
}

static int tda826x_sleep(struct dvb_frontend *fe)
{
	struct tda826x_priv *priv = fe->tuner_priv;
	int ret;
	u8 buf [] = { 0x00, 0x8d };
	struct i2c_msg msg = { .addr = priv->i2c_address, .flags = 0, .buf = buf, .len = 2 };

	dprintk("%s:\n", __func__);

	if (!priv->has_loopthrough)
		buf[1] = 0xad;

	if (fe->ops.i2c_gate_ctrl)
		fe->ops.i2c_gate_ctrl(fe, 1);
	if ((ret = i2c_transfer (priv->i2c, &msg, 1)) != 1) {
		dprintk("%s: i2c error\n", __func__);
	}
	if (fe->ops.i2c_gate_ctrl)
		fe->ops.i2c_gate_ctrl(fe, 0);

	return (ret == 1) ? 0 : ret;
}

static int tda826x_set_params(struct dvb_frontend *fe)
{
	struct dtv_frontend_properties *p = &fe->dtv_property_cache;
	struct tda826x_priv *priv = fe->tuner_priv;
	int ret;
	u32 div;
	u32 ksyms;
	u32 bandwidth;
	u8 buf [11];
	struct i2c_msg msg = { .addr = priv->i2c_address, .flags = 0, .buf = buf, .len = 11 };

	dprintk("%s:\n", __func__);

	div = (p->frequency + (1000-1)) / 1000;

	/* BW = ((1 + RO) * SR/2 + 5) * 1.3      [SR in MSPS, BW in MHz] */
	/* with R0 = 0.35 and some transformations: */
	ksyms = p->symbol_rate / 1000;
	bandwidth = (878 * ksyms + 6500000) / 1000000 + 1;
	if (bandwidth < 5)
		bandwidth = 5;
	else if (bandwidth > 36)
		bandwidth = 36;

	buf[0] = 0x00; // subaddress
	buf[1] = 0x09; // powerdown RSSI + the magic value 1
	if (!priv->has_loopthrough)
		buf[1] |= 0x20; // power down loopthrough if not needed
	buf[2] = (1<<5) | 0x0b; // 1Mhz + 0.45 VCO
	buf[3] = div >> 7;
	buf[4] = div << 1;
	buf[5] = ((bandwidth - 5) << 3) | 7; /* baseband cut-off */
	buf[6] = 0xfe; // baseband gain 9 db + no RF attenuation
	buf[7] = 0x83; // charge pumps at high, tests off
	buf[8] = 0x80; // recommended value 4 for AMPVCO + disable ports.
	buf[9] = 0x1a; // normal caltime + recommended values for SELTH + SELVTL
	buf[10] = 0xd4; // recommended value 13 for BBIAS + unknown bit set on

	if (fe->ops.i2c_gate_ctrl)
		fe->ops.i2c_gate_ctrl(fe, 1);
	if ((ret = i2c_transfer (priv->i2c, &msg, 1)) != 1) {
		dprintk("%s: i2c error\n", __func__);
	}
	if (fe->ops.i2c_gate_ctrl)
		fe->ops.i2c_gate_ctrl(fe, 0);

	priv->frequency = div * 1000;

	return (ret == 1) ? 0 : ret;
}

static int tda826x_get_frequency(struct dvb_frontend *fe, u32 *frequency)
{

Annotation

Implementation Notes