drivers/i3c/master/ast2600-i3c-master.c

Source file repositories/reference/linux-study-clean/drivers/i3c/master/ast2600-i3c-master.c

File Facts

System
Linux kernel
Corpus path
drivers/i3c/master/ast2600-i3c-master.c
Extension
.c
Size
5068 bytes
Lines
188
Domain
Driver Families
Bucket
drivers/i3c
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 ast2600_i3c {
	struct dw_i3c_master dw;
	struct regmap *global_regs;
	unsigned int global_idx;
	unsigned int sda_pullup;
};

static struct ast2600_i3c *to_ast2600_i3c(struct dw_i3c_master *dw)
{
	return container_of(dw, struct ast2600_i3c, dw);
}

static int ast2600_i3c_pullup_to_reg(unsigned int ohms, u32 *regp)
{
	u32 reg;

	switch (ohms) {
	case 2000:
		reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_2K;
		break;
	case 750:
		reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_750;
		break;
	case 545:
		reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_545;
		break;
	default:
		return -EINVAL;
	}

	if (regp)
		*regp = reg;

	return 0;
}

static int ast2600_i3c_init(struct dw_i3c_master *dw)
{
	struct ast2600_i3c *i3c = to_ast2600_i3c(dw);
	u32 reg = 0;
	int rc;

	/* reg0: set SDA pullup values */
	rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, &reg);
	if (rc)
		return rc;

	rc = regmap_write(i3c->global_regs,
			  AST2600_I3CG_REG0(i3c->global_idx), reg);
	if (rc)
		return rc;

	/* reg1: set up the instance id, but leave everything else disabled,
	 * as it's all for client mode
	 */
	reg = AST2600_I3CG_REG1_INST_ID(i3c->global_idx);
	rc = regmap_write(i3c->global_regs,
			  AST2600_I3CG_REG1(i3c->global_idx), reg);

	return rc;
}

static void ast2600_i3c_set_dat_ibi(struct dw_i3c_master *i3c,
				    struct i3c_dev_desc *dev,
				    bool enable, u32 *dat)
{
	/*
	 * The ast2600 i3c controller will lock up on receiving 4n+1-byte IBIs
	 * if the PEC is disabled. We have no way to restrict the length of
	 * IBIs sent to the controller, so we need to unconditionally enable
	 * PEC checking, which means we drop a byte of payload data
	 */
	if (enable && dev->info.bcr & I3C_BCR_IBI_PAYLOAD) {
		dev_warn_once(&i3c->base.dev,
		      "Enabling PEC workaround. IBI payloads will be truncated\n");
		*dat |= DEV_ADDR_TABLE_IBI_PEC;
	}
}

static const struct dw_i3c_platform_ops ast2600_i3c_ops = {
	.init = ast2600_i3c_init,
	.set_dat_ibi = ast2600_i3c_set_dat_ibi,
};

static int ast2600_i3c_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct of_phandle_args gspec;
	struct ast2600_i3c *i3c;
	int rc;

Annotation

Implementation Notes