// SPDX-License-Identifier: GPL-2.0// Register map access API - SCCB support #include <linux/i2c.h>#include <linux/module.h>#include <linux/regmap.h> #include "internal.h" /** * sccb_is_available - Check if the adapter supports SCCB protocol * @adap: I2C adapter * * Return true if the I2C adapter is capable of using SCCB helper functions, * false otherwise. */static bool sccb_is_available(struct i2c_adapter *adap){	u32 needed_funcs = I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_WRITE_BYTE_DATA; 	/*	 * If we ever want support for hardware doing SCCB natively, we will	 * introduce a sccb_xfer() callback to struct i2c_algorithm and check	 * for it here.	 */ 	return (i2c_get_functionality(adap) & needed_funcs) == needed_funcs;} /** * regmap_sccb_read - Read data from SCCB slave device * @context: Device that will be interacted with * @reg: Register to be read from * @val: Pointer to store read value * * This executes the 2-phase write transmission cycle that is followed by a * 2-phase read transmission cycle, returning negative errno else zero on * success. */static int regmap_sccb_read(void *context, unsigned int reg, unsigned int *val){	struct device *dev = context;	struct i2c_client *i2c = to_i2c_client(dev);	int ret;	union i2c_smbus_data data; 	i2c_lock_bus(i2c->adapter, I2C_LOCK_SEGMENT); 	ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags,			       I2C_SMBUS_WRITE, reg, I2C_SMBUS_BYTE, NULL);	if (ret < 0)		goto out; 	ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags,			       I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data);	if (ret < 0)		goto out; 	*val = data.byte;out:	i2c_unlock_bus(i2c->adapter, I2C_LOCK_SEGMENT); 	return ret;} /** * regmap_sccb_write - Write data to SCCB slave device * @context: Device that will be interacted with * @reg: Register to write to * @val: Value to be written * * This executes the SCCB 3-phase write transmission cycle, returning negative * errno else zero on success. */static int regmap_sccb_write(void *context, unsigned int reg, unsigned int val){	struct device *dev = context;	struct i2c_client *i2c = to_i2c_client(dev); 	return i2c_smbus_write_byte_data(i2c, reg, val);} static const struct regmap_bus regmap_sccb_bus = {	.reg_write = regmap_sccb_write,	.reg_read = regmap_sccb_read,}; static const struct regmap_bus *regmap_get_sccb_bus(struct i2c_client *i2c,					const struct regmap_config *config){	if (config->val_bits == 8 && config->reg_bits == 8 &&			sccb_is_available(i2c->adapter))		return &regmap_sccb_bus; 	return ERR_PTR(-ENOTSUPP);} struct regmap *__regmap_init_sccb(struct i2c_client *i2c,				  const struct regmap_config *config,				  struct lock_class_key *lock_key,				  const char *lock_name){	const struct regmap_bus *bus = regmap_get_sccb_bus(i2c, config); 	if (IS_ERR(bus))		return ERR_CAST(bus); 	return __regmap_init(&i2c->dev, bus, &i2c->dev, config,			     lock_key, lock_name);}EXPORT_SYMBOL_GPL(__regmap_init_sccb); struct regmap *__devm_regmap_init_sccb(struct i2c_client *i2c,				       const struct regmap_config *config,				       struct lock_class_key *lock_key,				       const char *lock_name){	const struct regmap_bus *bus = regmap_get_sccb_bus(i2c, config); 	if (IS_ERR(bus))		return ERR_CAST(bus); 	return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config,				  lock_key, lock_name);}EXPORT_SYMBOL_GPL(__devm_regmap_init_sccb); MODULE_DESCRIPTION("Register map access API - SCCB support");MODULE_LICENSE("GPL v2");