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regmap: Add support for SCCB 

This is an I2C subset.
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Merge tag 'regmap-sccb' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap into regmap-4.19

regmap: Add support for SCCB

This is an I2C subset.
This commit is contained in:
Mark Brown 2018-07-18 15:47:54 +01:00
parent e76ad18b56 bcf7eac3d9
commit e594a0636b
4 changed files with 168 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/base/regmap/Kconfig
View File

@ -45,3 +45,7 @@ config REGMAP_IRQ
config REGMAP_SOUNDWIRE
tristate
depends on SOUNDWIRE_BUS
config REGMAP_SCCB
tristate
depends on I2C

1
drivers/base/regmap/Makefile
View File

@ -15,3 +15,4 @@ obj-$(CONFIG_REGMAP_MMIO) += regmap-mmio.o
obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o
obj-$(CONFIG_REGMAP_W1) += regmap-w1.o
obj-$(CONFIG_REGMAP_SOUNDWIRE) += regmap-sdw.o
obj-$(CONFIG_REGMAP_SCCB) += regmap-sccb.o

128
drivers/base/regmap/regmap-sccb.c Normal file
View File

@ -0,0 +1,128 @@
// SPDX-License-Identifier: GPL-2.0
// Register map access API - SCCB support
#include <linux/regmap.h>
#include <linux/i2c.h>
#include <linux/module.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 wit
* @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 wit
* @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 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_LICENSE("GPL v2");

35
include/linux/regmap.h
View File

@ -514,6 +514,10 @@ struct regmap *__regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config,
struct lock_class_key *lock_key,
const char *lock_name);
struct regmap *__regmap_init_sccb(struct i2c_client *i2c,
const struct regmap_config *config,
struct lock_class_key *lock_key,
const char *lock_name);
struct regmap *__regmap_init_slimbus(struct slim_device *slimbus,
const struct regmap_config *config,
struct lock_class_key *lock_key,
@ -558,6 +562,10 @@ struct regmap *__devm_regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config,
struct lock_class_key *lock_key,
const char *lock_name);
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);
struct regmap *__devm_regmap_init_spi(struct spi_device *dev,
const struct regmap_config *config,
struct lock_class_key *lock_key,
@ -645,6 +653,19 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
__regmap_lockdep_wrapper(__regmap_init_i2c, #config, \
i2c, config)
/**
* regmap_init_sccb() - Initialise register map
*
* @i2c: Device that will be interacted with
* @config: Configuration for register map
*
* The return value will be an ERR_PTR() on error or a valid pointer to
* a struct regmap.
*/
#define regmap_init_sccb(i2c, config) \
__regmap_lockdep_wrapper(__regmap_init_sccb, #config, \
i2c, config)
/**
* regmap_init_slimbus() - Initialise register map
*
@ -797,6 +818,20 @@ bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
__regmap_lockdep_wrapper(__devm_regmap_init_i2c, #config, \
i2c, config)
/**
* devm_regmap_init_sccb() - Initialise managed register map
*
* @i2c: Device that will be interacted with
* @config: Configuration for register map
*
* The return value will be an ERR_PTR() on error or a valid pointer
* to a struct regmap. The regmap will be automatically freed by the
* device management code.
*/
#define devm_regmap_init_sccb(i2c, config) \
__regmap_lockdep_wrapper(__devm_regmap_init_sccb, #config, \
i2c, config)
/**
* devm_regmap_init_spi() - Initialise register map
*