drivers/i2c/busses/i2c-mt7621.c

Source file repositories/reference/linux-study-clean/drivers/i2c/busses/i2c-mt7621.c

File Facts

System
Linux kernel
Corpus path
drivers/i2c/busses/i2c-mt7621.c
Extension
.c
Size
8167 bytes
Lines
343
Domain
Driver Families
Bucket
drivers/i2c
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 mtk_i2c {
	void __iomem *base;
	struct device *dev;
	struct i2c_adapter adap;
	u32 bus_freq;
	u32 clk_div;
	u32 flags;
	struct clk *clk;
};

static int mtk_i2c_wait_idle(struct mtk_i2c *i2c)
{
	int ret;
	u32 val;

	ret = readl_relaxed_poll_timeout(i2c->base + REG_SM0CTL1_REG,
					 val, !(val & SM0CTL1_TRI),
					 10, TIMEOUT_MS * 1000);
	if (ret)
		dev_dbg(i2c->dev, "idle err(%d)\n", ret);

	return ret;
}

static void mtk_i2c_reset(struct mtk_i2c *i2c)
{
	int ret;

	ret = device_reset(i2c->adap.dev.parent);
	if (ret)
		dev_err(i2c->dev, "I2C reset failed!\n");

	/*
	 * Don't set SM0CTL0_ODRAIN as its bit meaning is inverted. To
	 * configure open-drain mode, this bit needs to be cleared.
	 */
	iowrite32(((i2c->clk_div << 16) & SM0CTL0_CLK_DIV_MASK) | SM0CTL0_EN |
		  SM0CTL0_SCL_STRETCH, i2c->base + REG_SM0CTL0_REG);
	iowrite32(0, i2c->base + REG_SM0CFG2_REG);
}

static void mtk_i2c_dump_reg(struct mtk_i2c *i2c)
{
	dev_dbg(i2c->dev,
		"SM0CFG2 %08x, SM0CTL0 %08x, SM0CTL1 %08x, SM0D0 %08x, SM0D1 %08x\n",
		ioread32(i2c->base + REG_SM0CFG2_REG),
		ioread32(i2c->base + REG_SM0CTL0_REG),
		ioread32(i2c->base + REG_SM0CTL1_REG),
		ioread32(i2c->base + REG_SM0D0_REG),
		ioread32(i2c->base + REG_SM0D1_REG));
}

static int mtk_i2c_check_ack(struct mtk_i2c *i2c, u32 expected)
{
	u32 ack = readl_relaxed(i2c->base + REG_SM0CTL1_REG);
	u32 ack_expected = (expected << 16) & SM0CTL1_ACK_MASK;

	return ((ack & ack_expected) == ack_expected) ? 0 : -ENXIO;
}

static int mtk_i2c_start(struct mtk_i2c *i2c)
{
	iowrite32(SM0CTL1_START | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG);
	return mtk_i2c_wait_idle(i2c);
}

static int mtk_i2c_stop(struct mtk_i2c *i2c)
{
	iowrite32(SM0CTL1_STOP | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG);
	return mtk_i2c_wait_idle(i2c);
}

static int mtk_i2c_cmd(struct mtk_i2c *i2c, u32 cmd, int page_len)
{
	iowrite32(cmd | SM0CTL1_TRI | SM0CTL1_PGLEN(page_len),
		  i2c->base + REG_SM0CTL1_REG);
	return mtk_i2c_wait_idle(i2c);
}

static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
			int num)
{
	struct mtk_i2c *i2c;
	struct i2c_msg *pmsg;
	u16 addr;
	int i, j, ret, len, page_len;
	u32 cmd;
	u32 data[2];

	i2c = i2c_get_adapdata(adap);

Annotation

Implementation Notes