drivers/net/dsa/vitesse-vsc73xx-spi.c

Source file repositories/reference/linux-study-clean/drivers/net/dsa/vitesse-vsc73xx-spi.c

File Facts

System
Linux kernel
Corpus path
drivers/net/dsa/vitesse-vsc73xx-spi.c
Extension
.c
Size
5151 bytes
Lines
230
Domain
Driver Families
Bucket
drivers/net
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 vsc73xx_spi {
	struct spi_device	*spi;
	struct mutex		lock; /* Protects SPI traffic */
	struct vsc73xx		vsc;
};

static const struct vsc73xx_ops vsc73xx_spi_ops;

static u8 vsc73xx_make_addr(u8 mode, u8 block, u8 subblock)
{
	u8 ret;

	ret =
	    (block & VSC73XX_CMD_SPI_BLOCK_MASK) << VSC73XX_CMD_SPI_BLOCK_SHIFT;
	ret |= (mode & 1) << VSC73XX_CMD_SPI_MODE_SHIFT;
	ret |= subblock & VSC73XX_CMD_SPI_SUBBLOCK_MASK;

	return ret;
}

static int vsc73xx_spi_read(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
			    u32 *val)
{
	struct vsc73xx_spi *vsc_spi = vsc->priv;
	struct spi_transfer t[2];
	struct spi_message m;
	u8 cmd[4];
	u8 buf[4];
	int ret;

	if (!vsc73xx_is_addr_valid(block, subblock))
		return -EINVAL;

	spi_message_init(&m);

	memset(&t, 0, sizeof(t));

	t[0].tx_buf = cmd;
	t[0].len = sizeof(cmd);
	spi_message_add_tail(&t[0], &m);

	t[1].rx_buf = buf;
	t[1].len = sizeof(buf);
	spi_message_add_tail(&t[1], &m);

	cmd[0] = vsc73xx_make_addr(VSC73XX_CMD_SPI_MODE_READ, block, subblock);
	cmd[1] = reg;
	cmd[2] = 0;
	cmd[3] = 0;

	mutex_lock(&vsc_spi->lock);
	ret = spi_sync(vsc_spi->spi, &m);
	mutex_unlock(&vsc_spi->lock);

	if (ret)
		return ret;

	*val = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];

	return 0;
}

static int vsc73xx_spi_write(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
			     u32 val)
{
	struct vsc73xx_spi *vsc_spi = vsc->priv;
	struct spi_transfer t[2];
	struct spi_message m;
	u8 cmd[2];
	u8 buf[4];
	int ret;

	if (!vsc73xx_is_addr_valid(block, subblock))
		return -EINVAL;

	spi_message_init(&m);

	memset(&t, 0, sizeof(t));

	t[0].tx_buf = cmd;
	t[0].len = sizeof(cmd);
	spi_message_add_tail(&t[0], &m);

	t[1].tx_buf = buf;
	t[1].len = sizeof(buf);
	spi_message_add_tail(&t[1], &m);

	cmd[0] = vsc73xx_make_addr(VSC73XX_CMD_SPI_MODE_WRITE, block, subblock);
	cmd[1] = reg;

Annotation

Implementation Notes