drivers/video/fbdev/bt455.h

Source file repositories/reference/linux-study-clean/drivers/video/fbdev/bt455.h

File Facts

System: Linux kernel
Corpus path: drivers/video/fbdev/bt455.h
Extension: .h
Size: 1879 bytes
Lines: 91
Domain: Driver Families
Bucket: drivers/video
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.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

linux/types.h

Detected Declarations

struct bt455_regs
function bt455_select_reg
function bt455_reset_reg
function bt455_read_cmap_next
function bt455_write_cmap_next
function bt455_write_ovly_next
function bt455_read_cmap_entry
function bt455_write_cmap_entry
function bt455_write_ovly_entry

Annotated Snippet

struct bt455_regs {
	volatile u8 addr_cmap;
	u8 pad0[3];
	volatile u8 addr_cmap_data;
	u8 pad1[3];
	volatile u8 addr_clr;
	u8 pad2[3];
	volatile u8 addr_ovly;
	u8 pad3[3];
};

static inline void bt455_select_reg(struct bt455_regs *regs, int ir)
{
	mb();
	regs->addr_cmap = ir & 0x0f;
}

static inline void bt455_reset_reg(struct bt455_regs *regs)
{
	mb();
	regs->addr_clr = 0;
}

/*
 * Read/write to a Bt455 color map register.
 */
static inline void bt455_read_cmap_next(struct bt455_regs *regs, u8 *grey)
{
	mb();
	regs->addr_cmap_data;
	rmb();
	*grey = regs->addr_cmap_data & 0xf;
	rmb();
	regs->addr_cmap_data;
}

static inline void bt455_write_cmap_next(struct bt455_regs *regs, u8 grey)
{
	wmb();
	regs->addr_cmap_data = 0x0;
	wmb();
	regs->addr_cmap_data = grey & 0xf;
	wmb();
	regs->addr_cmap_data = 0x0;
}

static inline void bt455_write_ovly_next(struct bt455_regs *regs, u8 grey)
{
	wmb();
	regs->addr_ovly = 0x0;
	wmb();
	regs->addr_ovly = grey & 0xf;
	wmb();
	regs->addr_ovly = 0x0;
}

static inline void bt455_read_cmap_entry(struct bt455_regs *regs,
					 int cr, u8 *grey)
{
	bt455_select_reg(regs, cr);
	bt455_read_cmap_next(regs, grey);
}

static inline void bt455_write_cmap_entry(struct bt455_regs *regs,
					  int cr, u8 grey)
{
	bt455_select_reg(regs, cr);
	bt455_write_cmap_next(regs, grey);
}

static inline void bt455_write_ovly_entry(struct bt455_regs *regs, u8 grey)
{
	bt455_reset_reg(regs);
	bt455_write_ovly_next(regs, grey);
}

Annotation

Immediate include surface: `linux/types.h`.
Detected declarations: `struct bt455_regs`, `function bt455_select_reg`, `function bt455_reset_reg`, `function bt455_read_cmap_next`, `function bt455_write_cmap_next`, `function bt455_write_ovly_next`, `function bt455_read_cmap_entry`, `function bt455_write_cmap_entry`, `function bt455_write_ovly_entry`.
Atlas domain: Driver Families / drivers/video.
Implementation status: source implementation candidate.

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.