diff options
Diffstat (limited to 'drivers/base/regmap/regmap.c')
-rw-r--r-- | drivers/base/regmap/regmap.c | 455 |
1 files changed, 455 insertions, 0 deletions
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c new file mode 100644 index 0000000..cf3565c --- /dev/null +++ b/drivers/base/regmap/regmap.c @@ -0,0 +1,455 @@ +/* + * 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/slab.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/err.h> + +#include <linux/regmap.h> + +struct regmap; + +struct regmap_format { + size_t buf_size; + size_t reg_bytes; + size_t val_bytes; + void (*format_write)(struct regmap *map, + unsigned int reg, unsigned int val); + void (*format_reg)(void *buf, unsigned int reg); + void (*format_val)(void *buf, unsigned int val); + unsigned int (*parse_val)(void *buf); +}; + +struct regmap { + struct mutex lock; + + struct device *dev; /* Device we do I/O on */ + void *work_buf; /* Scratch buffer used to format I/O */ + struct regmap_format format; /* Buffer format */ + const struct regmap_bus *bus; +}; + +static void regmap_format_4_12_write(struct regmap *map, + unsigned int reg, unsigned int val) +{ + __be16 *out = map->work_buf; + *out = cpu_to_be16((reg << 12) | val); +} + +static void regmap_format_7_9_write(struct regmap *map, + unsigned int reg, unsigned int val) +{ + __be16 *out = map->work_buf; + *out = cpu_to_be16((reg << 9) | val); +} + +static void regmap_format_8(void *buf, unsigned int val) +{ + u8 *b = buf; + + b[0] = val; +} + +static void regmap_format_16(void *buf, unsigned int val) +{ + __be16 *b = buf; + + b[0] = cpu_to_be16(val); +} + +static unsigned int regmap_parse_8(void *buf) +{ + u8 *b = buf; + + return b[0]; +} + +static unsigned int regmap_parse_16(void *buf) +{ + __be16 *b = buf; + + b[0] = be16_to_cpu(b[0]); + + return b[0]; +} + +/** + * regmap_init(): Initialise register map + * + * @dev: Device that will be interacted with + * @bus: Bus-specific callbacks to use with device + * @config: Configuration for register map + * + * The return value will be an ERR_PTR() on error or a valid pointer to + * a struct regmap. This function should generally not be called + * directly, it should be called by bus-specific init functions. + */ +struct regmap *regmap_init(struct device *dev, + const struct regmap_bus *bus, + const struct regmap_config *config) +{ + struct regmap *map; + int ret = -EINVAL; + + if (!bus || !config) + return NULL; + + map = kzalloc(sizeof(*map), GFP_KERNEL); + if (map == NULL) { + ret = -ENOMEM; + goto err; + } + + mutex_init(&map->lock); + map->format.buf_size = (config->reg_bits + config->val_bits) / 8; + map->format.reg_bytes = config->reg_bits / 8; + map->format.val_bytes = config->val_bits / 8; + map->dev = dev; + map->bus = bus; + + switch (config->reg_bits) { + case 4: + switch (config->val_bits) { + case 12: + map->format.format_write = regmap_format_4_12_write; + break; + default: + goto err_map; + } + break; + + case 7: + switch (config->val_bits) { + case 9: + map->format.format_write = regmap_format_7_9_write; + break; + default: + goto err_map; + } + break; + + case 8: + map->format.format_reg = regmap_format_8; + break; + + case 16: + map->format.format_reg = regmap_format_16; + break; + + default: + goto err_map; + } + + switch (config->val_bits) { + case 8: + map->format.format_val = regmap_format_8; + map->format.parse_val = regmap_parse_8; + break; + case 16: + map->format.format_val = regmap_format_16; + map->format.parse_val = regmap_parse_16; + break; + } + + if (!map->format.format_write && + !(map->format.format_reg && map->format.format_val)) + goto err_map; + + map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL); + if (map->work_buf == NULL) { + ret = -ENOMEM; + goto err_bus; + } + + return map; + +err_bus: + module_put(map->bus->owner); +err_map: + kfree(map); +err: + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(regmap_init); + +/** + * regmap_exit(): Free a previously allocated register map + */ +void regmap_exit(struct regmap *map) +{ + kfree(map->work_buf); + module_put(map->bus->owner); + kfree(map); +} +EXPORT_SYMBOL_GPL(regmap_exit); + +static int _regmap_raw_write(struct regmap *map, unsigned int reg, + const void *val, size_t val_len) +{ + void *buf; + int ret = -ENOTSUPP; + size_t len; + + map->format.format_reg(map->work_buf, reg); + + /* Try to do a gather write if we can */ + if (map->bus->gather_write) + ret = map->bus->gather_write(map->dev, map->work_buf, + map->format.reg_bytes, + val, val_len); + + /* Otherwise fall back on linearising by hand. */ + if (ret == -ENOTSUPP) { + len = map->format.reg_bytes + val_len; + buf = kmalloc(len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + memcpy(buf, map->work_buf, map->format.reg_bytes); + memcpy(buf + map->format.reg_bytes, val, val_len); + ret = map->bus->write(map->dev, buf, len); + + kfree(buf); + } + + return ret; +} + +static int _regmap_write(struct regmap *map, unsigned int reg, + unsigned int val) +{ + BUG_ON(!map->format.format_write && !map->format.format_val); + + if (map->format.format_write) { + map->format.format_write(map, reg, val); + + return map->bus->write(map->dev, map->work_buf, + map->format.buf_size); + } else { + map->format.format_val(map->work_buf + map->format.reg_bytes, + val); + return _regmap_raw_write(map, reg, + map->work_buf + map->format.reg_bytes, + map->format.val_bytes); + } +} + +/** + * regmap_write(): Write a value to a single register + * + * @map: Register map to write to + * @reg: Register to write to + * @val: Value to be written + * + * A value of zero will be returned on success, a negative errno will + * be returned in error cases. + */ +int regmap_write(struct regmap *map, unsigned int reg, unsigned int val) +{ + int ret; + + mutex_lock(&map->lock); + + ret = _regmap_write(map, reg, val); + + mutex_unlock(&map->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(regmap_write); + +/** + * regmap_raw_write(): Write raw values to one or more registers + * + * @map: Register map to write to + * @reg: Initial register to write to + * @val: Block of data to be written, laid out for direct transmission to the + * device + * @val_len: Length of data pointed to by val. + * + * This function is intended to be used for things like firmware + * download where a large block of data needs to be transferred to the + * device. No formatting will be done on the data provided. + * + * A value of zero will be returned on success, a negative errno will + * be returned in error cases. + */ +int regmap_raw_write(struct regmap *map, unsigned int reg, + const void *val, size_t val_len) +{ + int ret; + + mutex_lock(&map->lock); + + ret = _regmap_raw_write(map, reg, val, val_len); + + mutex_unlock(&map->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(regmap_raw_write); + +static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val, + unsigned int val_len) +{ + u8 *u8 = map->work_buf; + int ret; + + map->format.format_reg(map->work_buf, reg); + + /* + * Some buses flag reads by setting the high bits in the + * register addresss; since it's always the high bits for all + * current formats we can do this here rather than in + * formatting. This may break if we get interesting formats. + */ + if (map->bus->read_flag_mask) + u8[0] |= map->bus->read_flag_mask; + + ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes, + val, map->format.val_bytes); + if (ret != 0) + return ret; + + return 0; +} + +static int _regmap_read(struct regmap *map, unsigned int reg, + unsigned int *val) +{ + int ret; + + if (!map->format.parse_val) + return -EINVAL; + + ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes); + if (ret == 0) + *val = map->format.parse_val(map->work_buf); + + return ret; +} + +/** + * regmap_read(): Read a value from a single register + * + * @map: Register map to write to + * @reg: Register to be read from + * @val: Pointer to store read value + * + * A value of zero will be returned on success, a negative errno will + * be returned in error cases. + */ +int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val) +{ + int ret; + + mutex_lock(&map->lock); + + ret = _regmap_read(map, reg, val); + + mutex_unlock(&map->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(regmap_read); + +/** + * regmap_raw_read(): Read raw data from the device + * + * @map: Register map to write to + * @reg: First register to be read from + * @val: Pointer to store read value + * @val_len: Size of data to read + * + * A value of zero will be returned on success, a negative errno will + * be returned in error cases. + */ +int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, + size_t val_len) +{ + int ret; + + mutex_lock(&map->lock); + + ret = _regmap_raw_read(map, reg, val, val_len); + + mutex_unlock(&map->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(regmap_raw_read); + +/** + * regmap_bulk_read(): Read multiple registers from the device + * + * @map: Register map to write to + * @reg: First register to be read from + * @val: Pointer to store read value, in native register size for device + * @val_count: Number of registers to read + * + * A value of zero will be returned on success, a negative errno will + * be returned in error cases. + */ +int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val, + size_t val_count) +{ + int ret, i; + size_t val_bytes = map->format.val_bytes; + + if (!map->format.parse_val) + return -EINVAL; + + ret = regmap_raw_read(map, reg, val, val_bytes * val_count); + if (ret != 0) + return ret; + + for (i = 0; i < val_count * val_bytes; i += val_bytes) + map->format.parse_val(val + i); + + return 0; +} +EXPORT_SYMBOL_GPL(regmap_bulk_read); + +/** + * remap_update_bits: Perform a read/modify/write cycle on the register map + * + * @map: Register map to update + * @reg: Register to update + * @mask: Bitmask to change + * @val: New value for bitmask + * + * Returns zero for success, a negative number on error. + */ +int regmap_update_bits(struct regmap *map, unsigned int reg, + unsigned int mask, unsigned int val) +{ + int ret; + unsigned int tmp; + + mutex_lock(&map->lock); + + ret = _regmap_read(map, reg, &tmp); + if (ret != 0) + goto out; + + tmp &= ~mask; + tmp |= val & mask; + + ret = _regmap_write(map, reg, tmp); + +out: + mutex_unlock(&map->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(regmap_update_bits); |