drivers/spmi/spmi-apple-controller.c

Source file repositories/reference/linux-study-clean/drivers/spmi/spmi-apple-controller.c

File Facts

System
Linux kernel
Corpus path
drivers/spmi/spmi-apple-controller.c
Extension
.c
Size
3994 bytes
Lines
170
Domain
Driver Families
Bucket
drivers/spmi
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 apple_spmi {
	void __iomem *regs;
};

#define poll_reg(spmi, reg, val, cond) \
	readl_poll_timeout((spmi)->regs + (reg), (val), (cond), \
			   REG_POLL_INTERVAL_US, REG_POLL_TIMEOUT_US)

static inline u32 apple_spmi_pack_cmd(u8 opc, u8 sid, u16 saddr, size_t len)
{
	return opc | sid << 8 | saddr << 16 | (len - 1) | (1 << 15);
}

/* Wait for Rx FIFO to have something */
static int apple_spmi_wait_rx_not_empty(struct spmi_controller *ctrl)
{
	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
	int ret;
	u32 status;

	ret = poll_reg(spmi, SPMI_STATUS_REG, status, !(status & SPMI_RX_FIFO_EMPTY));
	if (ret) {
		dev_err(&ctrl->dev,
			"failed to wait for RX FIFO not empty\n");
		return ret;
	}

	return 0;
}

static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
			 u16 saddr, u8 *buf, size_t len)
{
	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
	u32 rsp;
	size_t len_read = 0;
	u8 i;
	int ret;

	writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);

	ret = apple_spmi_wait_rx_not_empty(ctrl);
	if (ret)
		return ret;

	/* Discard SPMI reply status */
	readl(spmi->regs + SPMI_RSP_REG);

	/* Read SPMI data reply */
	while (len_read < len) {
		rsp = readl(spmi->regs + SPMI_RSP_REG);
		i = 0;
		while ((len_read < len) && (i < 4)) {
			buf[len_read++] = ((0xff << (8 * i)) & rsp) >> (8 * i);
			i += 1;
		}
	}

	return 0;
}

static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
			  u16 saddr, const u8 *buf, size_t len)
{
	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
	size_t i = 0, j;
	int ret;

	writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);

	while (i < len) {
		j = 0;
		spmi_cmd = 0;
		while ((j < 4) & (i < len))
			spmi_cmd |= buf[i++] << (j++ * 8);

		writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);
	}

	ret = apple_spmi_wait_rx_not_empty(ctrl);
	if (ret)
		return ret;

	/* Discard */
	readl(spmi->regs + SPMI_RSP_REG);

	return 0;
}

Annotation

Implementation Notes