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// SPDX-License-Identifier: GPL-2.0 | ||
// Register map access API - SCCB support | ||
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#include <linux/i2c.h> | ||
#include <linux/module.h> | ||
#include <linux/regmap.h> | ||
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#include "internal.h" | ||
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/** | ||
* 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; | ||
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/* | ||
* 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. | ||
*/ | ||
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return (i2c_get_functionality(adap) & needed_funcs) == needed_funcs; | ||
} | ||
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/** | ||
* 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; | ||
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i2c_lock_bus(i2c->adapter, I2C_LOCK_SEGMENT); | ||
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ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags, | ||
I2C_SMBUS_WRITE, reg, I2C_SMBUS_BYTE, NULL); | ||
if (ret < 0) | ||
goto out; | ||
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ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags, | ||
I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data); | ||
if (ret < 0) | ||
goto out; | ||
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*val = data.byte; | ||
out: | ||
i2c_unlock_bus(i2c->adapter, I2C_LOCK_SEGMENT); | ||
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return ret; | ||
} | ||
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/** | ||
* 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); | ||
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return i2c_smbus_write_byte_data(i2c, reg, val); | ||
} | ||
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static struct regmap_bus regmap_sccb_bus = { | ||
.reg_write = regmap_sccb_write, | ||
.reg_read = regmap_sccb_read, | ||
}; | ||
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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; | ||
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return ERR_PTR(-ENOTSUPP); | ||
} | ||
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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); | ||
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if (IS_ERR(bus)) | ||
return ERR_CAST(bus); | ||
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return __regmap_init(&i2c->dev, bus, &i2c->dev, config, | ||
lock_key, lock_name); | ||
} | ||
EXPORT_SYMBOL_GPL(__regmap_init_sccb); | ||
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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); | ||
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if (IS_ERR(bus)) | ||
return ERR_CAST(bus); | ||
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return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config, | ||
lock_key, lock_name); | ||
} | ||
EXPORT_SYMBOL_GPL(__devm_regmap_init_sccb); | ||
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MODULE_LICENSE("GPL v2"); |
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