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 #include "internal.h"
  19
  20 struct regmap_async_spi {
  21         struct regmap_async core;
  22         struct spi_message m;
  23         struct spi_transfer t[2];
  24 };
  25
  26 static void regmap_spi_complete(void *data)
  27 {
  28         struct regmap_async_spi *async = data;
  29
  30         regmap_async_complete_cb(&async->core, async->m.status);
  31 }
  32
  33 static int regmap_spi_write(void *context, const void *data, size_t count)
  34 {
  35         struct device *dev = context;
  36         struct spi_device *spi = to_spi_device(dev);
  37
  38         return spi_write(spi, data, count);
  39 }
  40
  41 static int regmap_spi_gather_write(void *context,
  42                                    const void *reg, size_t reg_len,
  43                                    const void *val, size_t val_len)
  44 {
  45         struct device *dev = context;
  46         struct spi_device *spi = to_spi_device(dev);
  47         struct spi_message m;
  48         struct spi_transfer t[2] = { { .tx_buf = reg, .len = reg_len, },
  49                                      { .tx_buf = val, .len = val_len, }, };
  50
  51         spi_message_init(&m);
  52         spi_message_add_tail(&t[0], &m);
  53         spi_message_add_tail(&t[1], &m);
  54
  55         return spi_sync(spi, &m);
  56 }
  57
  58 static int regmap_spi_async_write(void *context,
  59                                   const void *reg, size_t reg_len,
  60                                   const void *val, size_t val_len,
  61                                   struct regmap_async *a)
  62 {
  63         struct regmap_async_spi *async = container_of(a,
  64                                                       struct regmap_async_spi,
  65                                                       core);
  66         struct device *dev = context;
  67         struct spi_device *spi = to_spi_device(dev);
  68
  69         async->t[0].tx_buf = reg;
  70         async->t[0].len = reg_len;
  71         async->t[1].tx_buf = val;
  72         async->t[1].len = val_len;
  73
  74         spi_message_init(&async->m);
  75         spi_message_add_tail(&async->t[0], &async->m);
  76         if (val)
  77                 spi_message_add_tail(&async->t[1], &async->m);
  78
  79         async->m.complete = regmap_spi_complete;
  80         async->m.context = async;
  81
  82         return spi_async(spi, &async->m);
  83 }
  84
  85 static struct regmap_async *regmap_spi_async_alloc(void)
  86 {
  87         struct regmap_async_spi *async_spi;
  88
  89         async_spi = kzalloc(sizeof(*async_spi), GFP_KERNEL);
  90         if (!async_spi)
  91                 return NULL;
  92
  93         return &async_spi->core;
  94 }
  95
  96 static int regmap_spi_read(void *context,
  97                            const void *reg, size_t reg_size,
  98                            void *val, size_t val_size)
  99 {
 100         struct device *dev = context;
 101         struct spi_device *spi = to_spi_device(dev);
 102
 103         return spi_write_then_read(spi, reg, reg_size, val, val_size);
 104 }
 105
 106 static struct regmap_bus regmap_spi = {
 107         .write = regmap_spi_write,
 108         .gather_write = regmap_spi_gather_write,
 109         .async_write = regmap_spi_async_write,
 110         .async_alloc = regmap_spi_async_alloc,
 111         .read = regmap_spi_read,
 112         .read_flag_mask = 0x80,
 113 };
 114
 115 /**
 116  * regmap_init_spi(): Initialise register map
 117  *
 118  * @spi: Device that will be interacted with
 119  * @config: Configuration for register map
 120  *
 121  * The return value will be an ERR_PTR() on error or a valid pointer to
 122  * a struct regmap.
 123  */
 124 struct regmap *regmap_init_spi(struct spi_device *spi,
 125                                const struct regmap_config *config)
 126 {
 127         return regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
 128 }
 129 EXPORT_SYMBOL_GPL(regmap_init_spi);
 130
 131 /**
 132  * devm_regmap_init_spi(): Initialise register map
 133  *
 134  * @spi: Device that will be interacted with
 135  * @config: Configuration for register map
 136  *
 137  * The return value will be an ERR_PTR() on error or a valid pointer
 138  * to a struct regmap.  The map will be automatically freed by the
 139  * device management code.
 140  */
 141 struct regmap *devm_regmap_init_spi(struct spi_device *spi,
 142                                     const struct regmap_config *config)
 143 {
 144         return devm_regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
 145 }
 146 EXPORT_SYMBOL_GPL(devm_regmap_init_spi);
 147
 148 MODULE_LICENSE("GPL");