drivers/media/dvb-frontends/nxt200x.c

Source file repositories/reference/linux-study-clean/drivers/media/dvb-frontends/nxt200x.c

File Facts

System
Linux kernel
Corpus path
drivers/media/dvb-frontends/nxt200x.c
Extension
.c
Size
29422 bytes
Lines
1221
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 nxt200x_state {

	struct i2c_adapter* i2c;
	const struct nxt200x_config* config;
	struct dvb_frontend frontend;

	/* demodulator private data */
	nxt_chip_type demod_chip;
	u8 initialised:1;
};

static int debug;
#define dprintk(args...)	do { if (debug) pr_debug(args); } while (0)

static int i2c_writebytes (struct nxt200x_state* state, u8 addr, u8 *buf, u8 len)
{
	int err;
	struct i2c_msg msg = { .addr = addr, .flags = 0, .buf = buf, .len = len };

	if ((err = i2c_transfer (state->i2c, &msg, 1)) != 1) {
		pr_warn("%s: i2c write error (addr 0x%02x, err == %i)\n",
			__func__, addr, err);
		return -EREMOTEIO;
	}
	return 0;
}

static int i2c_readbytes(struct nxt200x_state *state, u8 addr, u8 *buf, u8 len)
{
	int err;
	struct i2c_msg msg = { .addr = addr, .flags = I2C_M_RD, .buf = buf, .len = len };

	if ((err = i2c_transfer (state->i2c, &msg, 1)) != 1) {
		pr_warn("%s: i2c read error (addr 0x%02x, err == %i)\n",
			__func__, addr, err);
		return -EREMOTEIO;
	}
	return 0;
}

static int nxt200x_writebytes (struct nxt200x_state* state, u8 reg,
			       const u8 *buf, u8 len)
{
	u8 buf2[MAX_XFER_SIZE];
	int err;
	struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = buf2, .len = len + 1 };

	if (1 + len > sizeof(buf2)) {
		pr_warn("%s: i2c wr reg=%04x: len=%d is too big!\n",
			 __func__, reg, len);
		return -EINVAL;
	}

	buf2[0] = reg;
	memcpy(&buf2[1], buf, len);

	if ((err = i2c_transfer (state->i2c, &msg, 1)) != 1) {
		pr_warn("%s: i2c write error (addr 0x%02x, err == %i)\n",
			__func__, state->config->demod_address, err);
		return -EREMOTEIO;
	}
	return 0;
}

static int nxt200x_readbytes(struct nxt200x_state *state, u8 reg, u8 *buf, u8 len)
{
	u8 reg2 [] = { reg };

	struct i2c_msg msg [] = { { .addr = state->config->demod_address, .flags = 0, .buf = reg2, .len = 1 },
			{ .addr = state->config->demod_address, .flags = I2C_M_RD, .buf = buf, .len = len } };

	int err;

	if ((err = i2c_transfer (state->i2c, msg, 2)) != 2) {
		pr_warn("%s: i2c read error (addr 0x%02x, err == %i)\n",
			__func__, state->config->demod_address, err);
		return -EREMOTEIO;
	}
	return 0;
}

static u16 nxt200x_crc(u16 crc, u8 c)
{
	u8 i;
	u16 input = (u16) c & 0xFF;

	input<<=8;
	for(i=0; i<8; i++) {
		if((crc^input) & 0x8000)
			crc=(crc<<1)^CRC_CCIT_MASK;

Annotation

Implementation Notes