drivers/base/regmap/regmap-spi.c

   1 /*
   2  * Register map access API - SPI support
   3  *
   4  * Copyright 2011 Wolfson Microelectronics plc
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/regmap.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/init.h>
  16
  17 static int regmap_spi_write(struct device *dev, const void *data, size_t count)
  18 {
  19         struct spi_device *spi = to_spi_device(dev);
  20
  21         return spi_write(spi, data, count);
  22 }
  23
  24 static int regmap_spi_gather_write(struct device *dev,
  25                                    const void *reg, size_t reg_len,
  26                                    const void *val, size_t val_len)
  27 {
  28         struct spi_device *spi = to_spi_device(dev);
  29         struct spi_message m;
  30         struct spi_transfer t[2] = { { .tx_buf = reg, .len = reg_len, },
  31                                      { .tx_buf = val, .len = val_len, }, };
  32
  33         spi_message_init(&m);
  34         spi_message_add_tail(&t[0], &m);
  35         spi_message_add_tail(&t[1], &m);
  36
  37         return spi_sync(spi, &m);
  38 }
  39
  40 static int regmap_spi_read(struct device *dev,
  41                            const void *reg, size_t reg_size,
  42                            void *val, size_t val_size)
  43 {
  44         struct spi_device *spi = to_spi_device(dev);
  45
  46         return spi_write_then_read(spi, reg, reg_size, val, val_size);
  47 }
  48
  49 static struct regmap_bus regmap_spi = {
  50         .type = &spi_bus_type,
  51         .write = regmap_spi_write,
  52         .gather_write = regmap_spi_gather_write,
  53         .read = regmap_spi_read,
  54         .owner = THIS_MODULE,
  55         .read_flag_mask = 0x80,
  56 };
  57
  58 /**
  59  * regmap_init_spi(): Initialise register map
  60  *
  61  * @spi: Device that will be interacted with
  62  * @config: Configuration for register map
  63  *
  64  * The return value will be an ERR_PTR() on error or a valid pointer to
  65  * a struct regmap.
  66  */
  67 struct regmap *regmap_init_spi(struct spi_device *spi,
  68                                const struct regmap_config *config)
  69 {
  70         return regmap_init(&spi->dev, &regmap_spi, config);
  71 }
  72 EXPORT_SYMBOL_GPL(regmap_init_spi);