drivers/gpu/drm/ast/ast_ddc.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/ast/ast_ddc.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/ast/ast_ddc.c
Extension
.c
Size
5127 bytes
Lines
188
Domain
Driver Families
Bucket
drivers/gpu
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 ast_ddc {
	struct ast_device *ast;

	struct i2c_algo_bit_data bit;
	struct i2c_adapter adapter;
};

static void ast_ddc_algo_bit_data_setsda(void *data, int state)
{
	struct ast_ddc *ddc = data;
	struct ast_device *ast = ddc->ast;
	int i;
	u8 ujcrb7, jtemp;

	for (i = 0; i < 0x10000; i++) {
		ujcrb7 = ((state & 0x01) ? 0 : 1) << 2;
		ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0xf1, ujcrb7);
		jtemp = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x04);
		if (ujcrb7 == jtemp)
			break;
	}
}

static void ast_ddc_algo_bit_data_setscl(void *data, int state)
{
	struct ast_ddc *ddc = data;
	struct ast_device *ast = ddc->ast;
	int i;
	u8 ujcrb7, jtemp;

	for (i = 0; i < 0x10000; i++) {
		ujcrb7 = ((state & 0x01) ? 0 : 1);
		ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0xf4, ujcrb7);
		jtemp = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x01);
		if (ujcrb7 == jtemp)
			break;
	}
}

static int ast_ddc_algo_bit_data_pre_xfer(struct i2c_adapter *adapter)
{
	struct ast_ddc *ddc = i2c_get_adapdata(adapter);
	struct ast_device *ast = ddc->ast;

	/*
	 * Protect access to I/O registers from concurrent modesetting
	 * by acquiring the I/O-register lock.
	 */
	mutex_lock(&ast->modeset_lock);

	return 0;
}

static void ast_ddc_algo_bit_data_post_xfer(struct i2c_adapter *adapter)
{
	struct ast_ddc *ddc = i2c_get_adapdata(adapter);
	struct ast_device *ast = ddc->ast;

	mutex_unlock(&ast->modeset_lock);
}

static int ast_ddc_algo_bit_data_getsda(void *data)
{
	struct ast_ddc *ddc = data;
	struct ast_device *ast = ddc->ast;
	uint32_t val, val2, count, pass;

	count = 0;
	pass = 0;
	val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x20) >> 5) & 0x01;
	do {
		val2 = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x20) >> 5) & 0x01;
		if (val == val2) {
			pass++;
		} else {
			pass = 0;
			val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xb7, 0x20) >> 5) & 0x01;
		}
	} while ((pass < 5) && (count++ < 0x10000));

	return val & 1 ? 1 : 0;
}

static int ast_ddc_algo_bit_data_getscl(void *data)
{
	struct ast_ddc *ddc = data;
	struct ast_device *ast = ddc->ast;
	uint32_t val, val2, count, pass;

	count = 0;

Annotation

Implementation Notes