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linux-next/include/linux/regmap.h

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regmap: Add generic non-memory mapped register access API There are many places in the tree where we implement register access for devices on non-memory mapped buses, especially I2C and SPI. Since hardware designers seem to have settled on a relatively consistent set of register interfaces this can be effectively factored out into shared code. There are a standard set of formats for marshalling data for exchange with the device, with the actual I/O mechanisms generally being simple byte streams. We create an abstraction for marshaling data into formats which can be sent on the control interfaces, and create a standard method for plugging in actual transport underneath that. This is mostly a refactoring and renaming of the bottom level of the existing code for sharing register I/O which we have in ASoC. A subsequent patch in this series converts ASoC to use this. The main difference in interface is that reads return values by writing to a location provided by a pointer rather than in the return value, ensuring we can use the full range of the type for register data. We also use unsigned types rather than ints for the same reason. As some of the devices can have very large register maps the existing ASoC code also contains infrastructure for managing register caches. This cache work will be moved over in a future stage to allow for separate review, the current patch only deals with the physical I/O. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-05-12 01:59:58 +08:00
#ifndef __LINUX_REGMAP_H
#define __LINUX_REGMAP_H
/*
* Register map access API
*
* Copyright 2011 Wolfson Microelectronics plc
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/device.h>
#include <linux/list.h>
#include <linux/module.h>
regmap: Add I2C bus support Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-06-21 02:02:29 +08:00
struct i2c_client;
regmap: Add SPI bus support Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-05-12 17:42:10 +08:00
struct spi_device;
regmap: Add I2C bus support Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-06-21 02:02:29 +08:00
regmap: Allow drivers to specify register defaults It is useful for the register cache code to be able to specify the default values for the device registers. The major use is when restoring the register cache after suspend, knowing the register defaults allows us to skip registers that are at their default values when we resume which can be a substantial win on larger modern devices. For some devices (mostly older ones) the hardware does not support readback so the only way we can know the values is from code and so initializing the cache with default values makes it much easier for drivers work with read/modify/write updates. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-08-19 17:09:38 +08:00
/**
* Default value for a register. We use an array of structs rather
* than a simple array as many modern devices have very sparse
* register maps.
*
* @reg: Register address.
* @def: Register default value.
*/
struct reg_default {
unsigned int reg;
unsigned int def;
};
regmap: Add kerneldoc for struct regmap_config Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-07-21 05:28:58 +08:00
/**
* Configuration for the register map of a device.
*
* @reg_bits: Number of bits in a register address, mandatory.
* @val_bits: Number of bits in a register value, mandatory.
regmap: Allow devices to specify which registers are accessible This is currently unused but we need to know which registers exist and their properties in order to implement diagnostics like register map dumps and the cache features. We use callbacks partly because properties can vary at runtime (eg, through access locks on registers) and partly because big switch statements are a good compromise between readable code and small data size for providing information on big register maps. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-07-21 05:33:39 +08:00
*
regmap: Fix kerneldoc errors for regmap Field names didn't match between the documentation and the code. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-08-09 09:23:22 +08:00
* @writeable_reg: Optional callback returning true if the register
* can be written to.
* @readable_reg: Optional callback returning true if the register
* can be read from.
* @volatile_reg: Optional callback returning true if the register
* value can't be cached.
* @precious_reg: Optional callback returning true if the rgister
* should not be read outside of a call from the driver
* (eg, a clear on read interrupt status register).
regmap: Allow drivers to specify register defaults It is useful for the register cache code to be able to specify the default values for the device registers. The major use is when restoring the register cache after suspend, knowing the register defaults allows us to skip registers that are at their default values when we resume which can be a substantial win on larger modern devices. For some devices (mostly older ones) the hardware does not support readback so the only way we can know the values is from code and so initializing the cache with default values makes it much easier for drivers work with read/modify/write updates. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-08-19 17:09:38 +08:00
*
* @max_register: Optional, specifies the maximum valid register index.
* @reg_defaults: Power on reset values for registers (for use with
* register cache support).
* @num_reg_defaults: Number of elements in reg_defaults.
regmap: Add kerneldoc for struct regmap_config Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-07-21 05:28:58 +08:00
*/
regmap: Add generic non-memory mapped register access API There are many places in the tree where we implement register access for devices on non-memory mapped buses, especially I2C and SPI. Since hardware designers seem to have settled on a relatively consistent set of register interfaces this can be effectively factored out into shared code. There are a standard set of formats for marshalling data for exchange with the device, with the actual I/O mechanisms generally being simple byte streams. We create an abstraction for marshaling data into formats which can be sent on the control interfaces, and create a standard method for plugging in actual transport underneath that. This is mostly a refactoring and renaming of the bottom level of the existing code for sharing register I/O which we have in ASoC. A subsequent patch in this series converts ASoC to use this. The main difference in interface is that reads return values by writing to a location provided by a pointer rather than in the return value, ensuring we can use the full range of the type for register data. We also use unsigned types rather than ints for the same reason. As some of the devices can have very large register maps the existing ASoC code also contains infrastructure for managing register caches. This cache work will be moved over in a future stage to allow for separate review, the current patch only deals with the physical I/O. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-05-12 01:59:58 +08:00
struct regmap_config {
int reg_bits;
int val_bits;
regmap: Allow devices to specify which registers are accessible This is currently unused but we need to know which registers exist and their properties in order to implement diagnostics like register map dumps and the cache features. We use callbacks partly because properties can vary at runtime (eg, through access locks on registers) and partly because big switch statements are a good compromise between readable code and small data size for providing information on big register maps. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-07-21 05:33:39 +08:00
bool (*writeable_reg)(struct device *dev, unsigned int reg);
bool (*readable_reg)(struct device *dev, unsigned int reg);
bool (*volatile_reg)(struct device *dev, unsigned int reg);
regmap: Add precious registers to the driver interface Some devices are sensitive to reads on their registers, especially for things like clear on read interrupt status registers. Avoid creating problems with these with things like debugfs by allowing drivers to tell the core about them. If a register is marked as precious then the core will not internally generate any reads of it. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-08-08 14:40:22 +08:00
bool (*precious_reg)(struct device *dev, unsigned int reg);
regmap: Allow drivers to specify register defaults It is useful for the register cache code to be able to specify the default values for the device registers. The major use is when restoring the register cache after suspend, knowing the register defaults allows us to skip registers that are at their default values when we resume which can be a substantial win on larger modern devices. For some devices (mostly older ones) the hardware does not support readback so the only way we can know the values is from code and so initializing the cache with default values makes it much easier for drivers work with read/modify/write updates. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-08-19 17:09:38 +08:00
unsigned int max_register;
struct reg_default *reg_defaults;
int num_reg_defaults;
regmap: Add generic non-memory mapped register access API There are many places in the tree where we implement register access for devices on non-memory mapped buses, especially I2C and SPI. Since hardware designers seem to have settled on a relatively consistent set of register interfaces this can be effectively factored out into shared code. There are a standard set of formats for marshalling data for exchange with the device, with the actual I/O mechanisms generally being simple byte streams. We create an abstraction for marshaling data into formats which can be sent on the control interfaces, and create a standard method for plugging in actual transport underneath that. This is mostly a refactoring and renaming of the bottom level of the existing code for sharing register I/O which we have in ASoC. A subsequent patch in this series converts ASoC to use this. The main difference in interface is that reads return values by writing to a location provided by a pointer rather than in the return value, ensuring we can use the full range of the type for register data. We also use unsigned types rather than ints for the same reason. As some of the devices can have very large register maps the existing ASoC code also contains infrastructure for managing register caches. This cache work will be moved over in a future stage to allow for separate review, the current patch only deals with the physical I/O. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-05-12 01:59:58 +08:00
};
typedef int (*regmap_hw_write)(struct device *dev, const void *data,
size_t count);
typedef int (*regmap_hw_gather_write)(struct device *dev,
const void *reg, size_t reg_len,
const void *val, size_t val_len);
typedef int (*regmap_hw_read)(struct device *dev,
const void *reg_buf, size_t reg_size,
void *val_buf, size_t val_size);
/**
* Description of a hardware bus for the register map infrastructure.
*
* @write: Write operation.
* @gather_write: Write operation with split register/value, return -ENOTSUPP
* if not implemented on a given device.
* @read: Read operation. Data is returned in the buffer used to transmit
* data.
* @read_flag_mask: Mask to be set in the top byte of the register when doing
* a read.
*/
struct regmap_bus {
regmap_hw_write write;
regmap_hw_gather_write gather_write;
regmap_hw_read read;
u8 read_flag_mask;
};
struct regmap *regmap_init(struct device *dev,
const struct regmap_bus *bus,
const struct regmap_config *config);
regmap: Add I2C bus support Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-06-21 02:02:29 +08:00
struct regmap *regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config);
regmap: Add SPI bus support Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-05-12 17:42:10 +08:00
struct regmap *regmap_init_spi(struct spi_device *dev,
const struct regmap_config *config);
regmap: Add generic non-memory mapped register access API There are many places in the tree where we implement register access for devices on non-memory mapped buses, especially I2C and SPI. Since hardware designers seem to have settled on a relatively consistent set of register interfaces this can be effectively factored out into shared code. There are a standard set of formats for marshalling data for exchange with the device, with the actual I/O mechanisms generally being simple byte streams. We create an abstraction for marshaling data into formats which can be sent on the control interfaces, and create a standard method for plugging in actual transport underneath that. This is mostly a refactoring and renaming of the bottom level of the existing code for sharing register I/O which we have in ASoC. A subsequent patch in this series converts ASoC to use this. The main difference in interface is that reads return values by writing to a location provided by a pointer rather than in the return value, ensuring we can use the full range of the type for register data. We also use unsigned types rather than ints for the same reason. As some of the devices can have very large register maps the existing ASoC code also contains infrastructure for managing register caches. This cache work will be moved over in a future stage to allow for separate review, the current patch only deals with the physical I/O. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Liam Girdwood <lrg@ti.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca>
2011-05-12 01:59:58 +08:00
void regmap_exit(struct regmap *map);
int regmap_write(struct regmap *map, unsigned int reg, unsigned int val);
int regmap_raw_write(struct regmap *map, unsigned int reg,
const void *val, size_t val_len);
int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
int regmap_raw_read(struct regmap *map, unsigned int reg,
void *val, size_t val_len);
int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
size_t val_count);
int regmap_update_bits(struct regmap *map, unsigned int reg,
unsigned int mask, unsigned int val);
#endif
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