drivers/spi/spi-mpc52xx-psc.c

Source file repositories/reference/linux-study-clean/drivers/spi/spi-mpc52xx-psc.c

File Facts

System
Linux kernel
Corpus path
drivers/spi/spi-mpc52xx-psc.c
Extension
.c
Size
9708 bytes
Lines
367
Domain
Driver Families
Bucket
drivers/spi
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 mpc52xx_psc_spi {
	/* driver internal data */
	struct mpc52xx_psc __iomem *psc;
	struct mpc52xx_psc_fifo __iomem *fifo;
	int irq;
	u8 bits_per_word;

	struct completion done;
};

/* controller state */
struct mpc52xx_psc_spi_cs {
	int bits_per_word;
	int speed_hz;
};

/* set clock freq, clock ramp, bits per work
 * if t is NULL then reset the values to the default values
 */
static int mpc52xx_psc_spi_transfer_setup(struct spi_device *spi,
		struct spi_transfer *t)
{
	struct mpc52xx_psc_spi_cs *cs = spi->controller_state;

	cs->speed_hz = (t && t->speed_hz)
			? t->speed_hz : spi->max_speed_hz;
	cs->bits_per_word = (t && t->bits_per_word)
			? t->bits_per_word : spi->bits_per_word;
	cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
	return 0;
}

static void mpc52xx_psc_spi_activate_cs(struct spi_device *spi)
{
	struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
	struct mpc52xx_psc_spi *mps = spi_controller_get_devdata(spi->controller);
	struct mpc52xx_psc __iomem *psc = mps->psc;
	u32 sicr;
	u16 ccr;

	sicr = in_be32(&psc->sicr);

	/* Set clock phase and polarity */
	if (spi->mode & SPI_CPHA)
		sicr |= 0x00001000;
	else
		sicr &= ~0x00001000;
	if (spi->mode & SPI_CPOL)
		sicr |= 0x00002000;
	else
		sicr &= ~0x00002000;

	if (spi->mode & SPI_LSB_FIRST)
		sicr |= 0x10000000;
	else
		sicr &= ~0x10000000;
	out_be32(&psc->sicr, sicr);

	/* Set clock frequency and bits per word
	 * Because psc->ccr is defined as 16bit register instead of 32bit
	 * just set the lower byte of BitClkDiv
	 */
	ccr = in_be16((u16 __iomem *)&psc->ccr);
	ccr &= 0xFF00;
	if (cs->speed_hz)
		ccr |= (MCLK / cs->speed_hz - 1) & 0xFF;
	else /* by default SPI Clk 1MHz */
		ccr |= (MCLK / 1000000 - 1) & 0xFF;
	out_be16((u16 __iomem *)&psc->ccr, ccr);
	mps->bits_per_word = cs->bits_per_word;
}

#define MPC52xx_PSC_BUFSIZE (MPC52xx_PSC_RFNUM_MASK + 1)
/* wake up when 80% fifo full */
#define MPC52xx_PSC_RFALARM (MPC52xx_PSC_BUFSIZE * 20 / 100)

static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
						struct spi_transfer *t)
{
	struct mpc52xx_psc_spi *mps = spi_controller_get_devdata(spi->controller);
	struct mpc52xx_psc __iomem *psc = mps->psc;
	struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
	unsigned rb = 0;	/* number of bytes received */
	unsigned sb = 0;	/* number of bytes sent */
	unsigned char *rx_buf = (unsigned char *)t->rx_buf;
	unsigned char *tx_buf = (unsigned char *)t->tx_buf;
	unsigned rfalarm;
	unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
	unsigned recv_at_once;
	int last_block = 0;

Annotation

Implementation Notes