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 #include <linux/module.h>
  17
  18 static int regmap_spi_write(void *context, const void *data, size_t count)
  19 {
  20         struct device *dev = context;
  21         struct spi_device *spi = to_spi_device(dev);
  22
  23         return spi_write(spi, data, count);
  24 }
  25
  26 static int regmap_spi_gather_write(void *context,
  27                                    const void *reg, size_t reg_len,
  28                                    const void *val, size_t val_len)
  29 {
  30         struct device *dev = context;
  31         struct spi_device *spi = to_spi_device(dev);
  32         struct spi_message m;
  33         struct spi_transfer t[2] = { { .tx_buf = reg, .len = reg_len, },
  34                                      { .tx_buf = val, .len = val_len, }, };
  35
  36         spi_message_init(&m);
  37         spi_message_add_tail(&t[0], &m);
  38         spi_message_add_tail(&t[1], &m);
  39
  40         return spi_sync(spi, &m);
  41 }
  42
  43 static int regmap_spi_read(void *context,
  44                            const void *reg, size_t reg_size,
  45                            void *val, size_t val_size)
  46 {
  47         struct device *dev = context;
  48         struct spi_device *spi = to_spi_device(dev);
  49
  50         return spi_write_then_read(spi, reg, reg_size, val, val_size);
  51 }
  52
  53 static struct regmap_bus regmap_spi = {
  54         .write = regmap_spi_write,
  55         .gather_write = regmap_spi_gather_write,
  56         .read = regmap_spi_read,
  57         .read_flag_mask = 0x80,
  58 };
  59
  60 /**
  61  * regmap_init_spi(): Initialise register map
  62  *
  63  * @spi: Device that will be interacted with
  64  * @config: Configuration for register map
  65  *
  66  * The return value will be an ERR_PTR() on error or a valid pointer to
  67  * a struct regmap.
  68  */
  69 struct regmap *regmap_init_spi(struct spi_device *spi,
  70                                const struct regmap_config *config)
  71 {
  72         return regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
  73 }
  74 EXPORT_SYMBOL_GPL(regmap_init_spi);
  75
  76 /**
  77  * devm_regmap_init_spi(): Initialise register map
  78  *
  79  * @spi: Device that will be interacted with
  80  * @config: Configuration for register map
  81  *
  82  * The return value will be an ERR_PTR() on error or a valid pointer
  83  * to a struct regmap.  The map will be automatically freed by the
  84  * device management code.
  85  */
  86 struct regmap *devm_regmap_init_spi(struct spi_device *spi,
  87                                     const struct regmap_config *config)
  88 {
  89         return devm_regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
  90 }
  91 EXPORT_SYMBOL_GPL(devm_regmap_init_spi);
  92
  93 MODULE_LICENSE("GPL");