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// 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 ®map_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");
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