drivers/i2c/busses/i2c-microchip-corei2c.c

File Facts

System

Linux kernel

Corpus path

drivers/i2c/busses/i2c-microchip-corei2c.c

Extension

.c

Size

16927 bytes

Lines

650

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.

• 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.
• Touches IRQ or DMA behavior; this matters for the representative real-device path.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/clk.h
• linux/clkdev.h
• linux/err.h
• linux/i2c.h
• linux/interrupt.h
• linux/io.h
• linux/kernel.h
• linux/module.h
• linux/platform_device.h

Detected Declarations

• struct mchp_corei2c_dev
• function mchp_corei2c_core_disable
• function mchp_corei2c_core_enable
• function mchp_corei2c_reset
• function mchp_corei2c_stop
• function mchp_corei2c_set_divisor
• function mchp_corei2c_init
• function mchp_corei2c_empty_rx
• function mchp_corei2c_fill_tx
• function mchp_corei2c_next_msg
• function mchp_corei2c_handle_isr
• function mchp_corei2c_isr
• function mchp_corei2c_xfer
• function mchp_corei2c_func
• function mchp_corei2c_smbus_xfer
• function mchp_corei2c_probe
• function mchp_corei2c_remove

Annotated Snippet

struct mchp_corei2c_dev {
	void __iomem *base;
	struct device *dev;
	struct clk *i2c_clk;
	struct i2c_msg *msg_queue;
	u8 *buf;
	struct completion msg_complete;
	struct i2c_adapter adapter;
	int msg_err;
	int total_num;
	int current_num;
	u32 bus_clk_rate;
	u32 isr_status;
	u16 msg_len;
	u8 addr;
	bool restart_needed;
};

static void mchp_corei2c_core_disable(struct mchp_corei2c_dev *idev)
{
	u8 ctrl = readb(idev->base + CORE_I2C_CTRL);

	ctrl &= ~CTRL_ENS1;
	writeb(ctrl, idev->base + CORE_I2C_CTRL);
}

static void mchp_corei2c_core_enable(struct mchp_corei2c_dev *idev)
{
	u8 ctrl = readb(idev->base + CORE_I2C_CTRL);

	ctrl |= CTRL_ENS1;
	writeb(ctrl, idev->base + CORE_I2C_CTRL);
}

static void mchp_corei2c_reset(struct mchp_corei2c_dev *idev)
{
	mchp_corei2c_core_disable(idev);
	mchp_corei2c_core_enable(idev);
}

static inline void mchp_corei2c_stop(struct mchp_corei2c_dev *idev)
{
	u8 ctrl = readb(idev->base + CORE_I2C_CTRL);

	ctrl |= CTRL_STO;
	writeb(ctrl, idev->base + CORE_I2C_CTRL);
}

static inline int mchp_corei2c_set_divisor(u32 rate,
					   struct mchp_corei2c_dev *idev)
{
	u8 clkval, ctrl;

	if (rate >= 960)
		clkval = PCLK_DIV_960;
	else if (rate >= 256)
		clkval = PCLK_DIV_256;
	else if (rate >= 224)
		clkval = PCLK_DIV_224;
	else if (rate >= 192)
		clkval = PCLK_DIV_192;
	else if (rate >= 160)
		clkval = PCLK_DIV_160;
	else if (rate >= 120)
		clkval = PCLK_DIV_120;
	else if (rate >= 60)
		clkval = PCLK_DIV_60;
	else if (rate >= 8)
		clkval = BCLK_DIV_8;
	else
		return -EINVAL;

	ctrl = readb(idev->base + CORE_I2C_CTRL);
	ctrl &= ~CLK_MASK;
	ctrl |= clkval;
	writeb(ctrl, idev->base + CORE_I2C_CTRL);

	ctrl = readb(idev->base + CORE_I2C_CTRL);
	if ((ctrl & CLK_MASK) != clkval)
		return -EIO;

	return 0;
}

static int mchp_corei2c_init(struct mchp_corei2c_dev *idev)
{
	u32 clk_rate = clk_get_rate(idev->i2c_clk);
	u32 divisor = clk_rate / idev->bus_clk_rate;
	int ret;

Annotation

• Immediate include surface: `linux/clk.h`, `linux/clkdev.h`, `linux/err.h`, `linux/i2c.h`, `linux/interrupt.h`, `linux/io.h`, `linux/kernel.h`, `linux/module.h`.
• Detected declarations: `struct mchp_corei2c_dev`, `function mchp_corei2c_core_disable`, `function mchp_corei2c_core_enable`, `function mchp_corei2c_reset`, `function mchp_corei2c_stop`, `function mchp_corei2c_set_divisor`, `function mchp_corei2c_init`, `function mchp_corei2c_empty_rx`, `function mchp_corei2c_fill_tx`, `function mchp_corei2c_next_msg`.
• Atlas domain: Driver Families / drivers/i2c.
• Implementation status: source implementation candidate.
• IRQ or DMA behavior appears here, which is relevant to the selected PCIe/NVMe device path.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.