--- /dev/null
+/*
+ * 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);
--- /dev/null
+#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>
+
+struct regmap_config {
+ int reg_bits;
+ int val_bits;
+};
+
+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.
+ *
+ * @list: Internal use.
+ * @type: Bus type, used to identify bus to be used for a device.
+ * @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.
+ * @owner: Module with the bus implementation, used to pin the implementation
+ * in memory.
+ * @read_flag_mask: Mask to be set in the top byte of the register when doing
+ * a read.
+ */
+struct regmap_bus {
+ struct list_head list;
+ struct bus_type *type;
+ regmap_hw_write write;
+ regmap_hw_gather_write gather_write;
+ regmap_hw_read read;
+ struct module *owner;
+ u8 read_flag_mask;
+};
+
+struct regmap *regmap_init(struct device *dev,
+ const struct regmap_bus *bus,
+ const struct regmap_config *config);
+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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