drivers/spi/spi-realtek-rtl.c

Source file repositories/reference/linux-study-clean/drivers/spi/spi-realtek-rtl.c

File Facts

System
Linux kernel
Corpus path
drivers/spi/spi-realtek-rtl.c
Extension
.c
Size
4671 bytes
Lines
209
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 rtspi {
	void __iomem *base;
};

/* SPI Flash Configuration Register */
#define RTL_SPI_SFCR			0x00
#define RTL_SPI_SFCR_RBO		BIT(28)
#define RTL_SPI_SFCR_WBO		BIT(27)

/* SPI Flash Control and Status Register */
#define RTL_SPI_SFCSR			0x08
#define RTL_SPI_SFCSR_CSB0		BIT(31)
#define RTL_SPI_SFCSR_CSB1		BIT(30)
#define RTL_SPI_SFCSR_RDY		BIT(27)
#define RTL_SPI_SFCSR_CS		BIT(24)
#define RTL_SPI_SFCSR_LEN_MASK		~(0x03 << 28)
#define RTL_SPI_SFCSR_LEN1		(0x00 << 28)
#define RTL_SPI_SFCSR_LEN4		(0x03 << 28)

/* SPI Flash Data Register */
#define RTL_SPI_SFDR			0x0c

#define REG(x)		(rtspi->base + x)


static void rt_set_cs(struct spi_device *spi, bool active)
{
	struct rtspi *rtspi = spi_controller_get_devdata(spi->controller);
	u32 value;

	/* CS0 bit is active low */
	value = readl(REG(RTL_SPI_SFCSR));
	if (active)
		value |= RTL_SPI_SFCSR_CSB0;
	else
		value &= ~RTL_SPI_SFCSR_CSB0;
	writel(value, REG(RTL_SPI_SFCSR));
}

static void set_size(struct rtspi *rtspi, int size)
{
	u32 value;

	value = readl(REG(RTL_SPI_SFCSR));
	value &= RTL_SPI_SFCSR_LEN_MASK;
	if (size == 4)
		value |= RTL_SPI_SFCSR_LEN4;
	else if (size == 1)
		value |= RTL_SPI_SFCSR_LEN1;
	writel(value, REG(RTL_SPI_SFCSR));
}

static inline void wait_ready(struct rtspi *rtspi)
{
	while (!(readl(REG(RTL_SPI_SFCSR)) & RTL_SPI_SFCSR_RDY))
		cpu_relax();
}
static void send4(struct rtspi *rtspi, const u32 *buf)
{
	wait_ready(rtspi);
	set_size(rtspi, 4);
	writel(*buf, REG(RTL_SPI_SFDR));
}

static void send1(struct rtspi *rtspi, const u8 *buf)
{
	wait_ready(rtspi);
	set_size(rtspi, 1);
	writel(buf[0] << 24, REG(RTL_SPI_SFDR));
}

static void rcv4(struct rtspi *rtspi, u32 *buf)
{
	wait_ready(rtspi);
	set_size(rtspi, 4);
	*buf = readl(REG(RTL_SPI_SFDR));
}

static void rcv1(struct rtspi *rtspi, u8 *buf)
{
	wait_ready(rtspi);
	set_size(rtspi, 1);
	*buf = readl(REG(RTL_SPI_SFDR)) >> 24;
}

static int transfer_one(struct spi_controller *ctrl, struct spi_device *spi,
			struct spi_transfer *xfer)
{
	struct rtspi *rtspi = spi_controller_get_devdata(ctrl);
	void *rx_buf;

Annotation

Implementation Notes