drivers/net/dsa/xrs700x/xrs700x_i2c.c

Source file repositories/reference/linux-study-clean/drivers/net/dsa/xrs700x/xrs700x_i2c.c

File Facts

System
Linux kernel
Corpus path
drivers/net/dsa/xrs700x/xrs700x_i2c.c
Extension
.c
Size
3628 bytes
Lines
161
Domain
Driver Families
Bucket
drivers/net
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 xrs700x_i2c_cmd {
	__be32 reg;
	__be16 val;
} __packed;

static int xrs700x_i2c_reg_read(void *context, unsigned int reg,
				unsigned int *val)
{
	struct device *dev = context;
	struct i2c_client *i2c = to_i2c_client(dev);
	struct xrs700x_i2c_cmd cmd;
	int ret;

	cmd.reg = cpu_to_be32(reg | 1);

	ret = i2c_master_send(i2c, (char *)&cmd.reg, sizeof(cmd.reg));
	if (ret < 0) {
		dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
		return ret;
	}

	ret = i2c_master_recv(i2c, (char *)&cmd.val, sizeof(cmd.val));
	if (ret < 0) {
		dev_err(dev, "xrs i2c_master_recv returned %d\n", ret);
		return ret;
	}

	*val = be16_to_cpu(cmd.val);
	return 0;
}

static int xrs700x_i2c_reg_write(void *context, unsigned int reg,
				 unsigned int val)
{
	struct device *dev = context;
	struct i2c_client *i2c = to_i2c_client(dev);
	struct xrs700x_i2c_cmd cmd;
	int ret;

	cmd.reg = cpu_to_be32(reg);
	cmd.val = cpu_to_be16(val);

	ret = i2c_master_send(i2c, (char *)&cmd, sizeof(cmd));
	if (ret < 0) {
		dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
		return ret;
	}

	return 0;
}

static const struct regmap_config xrs700x_i2c_regmap_config = {
	.val_bits = 16,
	.reg_stride = 2,
	.reg_bits = 32,
	.pad_bits = 0,
	.write_flag_mask = 0,
	.read_flag_mask = 0,
	.reg_read = xrs700x_i2c_reg_read,
	.reg_write = xrs700x_i2c_reg_write,
	.max_register = 0,
	.cache_type = REGCACHE_NONE,
	.reg_format_endian = REGMAP_ENDIAN_BIG,
	.val_format_endian = REGMAP_ENDIAN_BIG
};

static int xrs700x_i2c_probe(struct i2c_client *i2c)
{
	struct xrs700x *priv;
	int ret;

	priv = xrs700x_switch_alloc(&i2c->dev, i2c);
	if (!priv)
		return -ENOMEM;

	priv->regmap = devm_regmap_init(&i2c->dev, NULL, &i2c->dev,
					&xrs700x_i2c_regmap_config);
	if (IS_ERR(priv->regmap)) {
		ret = PTR_ERR(priv->regmap);
		dev_err(&i2c->dev, "Failed to initialize regmap: %d\n", ret);
		return ret;
	}

	i2c_set_clientdata(i2c, priv);

	ret = xrs700x_switch_register(priv);

	/* Main DSA driver may not be started yet. */
	if (ret)
		return ret;

Annotation

Implementation Notes