linux/drivers/mfd/tps65912-spi.c
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   1/*
   2 * tps65912-spi.c  --  SPI access for TI TPS65912x PMIC
   3 *
   4 * Copyright 2011 Texas Instruments Inc.
   5 *
   6 * Author: Margarita Olaya Cabrera <magi@slimlogic.co.uk>
   7 *
   8 *  This program is free software; you can redistribute it and/or modify it
   9 *  under  the terms of the GNU General  Public License as published by the
  10 *  Free Software Foundation;  either version 2 of the License, or (at your
  11 *  option) any later version.
  12 *
  13 *  This driver is based on wm8350 implementation.
  14 */
  15
  16#include <linux/module.h>
  17#include <linux/moduleparam.h>
  18#include <linux/init.h>
  19#include <linux/slab.h>
  20#include <linux/gpio.h>
  21#include <linux/spi/spi.h>
  22#include <linux/mfd/core.h>
  23#include <linux/mfd/tps65912.h>
  24
  25static int tps65912_spi_write(struct tps65912 *tps65912, u8 addr,
  26                                                        int bytes, void *src)
  27{
  28        struct spi_device *spi = tps65912->control_data;
  29        u8 *data = (u8 *) src;
  30        int ret;
  31        /* bit 23 is the read/write bit */
  32        unsigned long spi_data = 1 << 23 | addr << 15 | *data;
  33        struct spi_transfer xfer;
  34        struct spi_message msg;
  35        u32 tx_buf, rx_buf;
  36
  37        tx_buf = spi_data;
  38        rx_buf = 0;
  39
  40        xfer.tx_buf     = &tx_buf;
  41        xfer.rx_buf     = NULL;
  42        xfer.len        = sizeof(unsigned long);
  43        xfer.bits_per_word = 24;
  44
  45        spi_message_init(&msg);
  46        spi_message_add_tail(&xfer, &msg);
  47
  48        ret = spi_sync(spi, &msg);
  49        return ret;
  50}
  51
  52static int tps65912_spi_read(struct tps65912 *tps65912, u8 addr,
  53                                                        int bytes, void *dest)
  54{
  55        struct spi_device *spi = tps65912->control_data;
  56        /* bit 23 is the read/write bit */
  57        unsigned long spi_data = 0 << 23 | addr << 15;
  58        struct spi_transfer xfer;
  59        struct spi_message msg;
  60        int ret;
  61        u8 *data = (u8 *) dest;
  62        u32 tx_buf, rx_buf;
  63
  64        tx_buf = spi_data;
  65        rx_buf = 0;
  66
  67        xfer.tx_buf     = &tx_buf;
  68        xfer.rx_buf     = &rx_buf;
  69        xfer.len        = sizeof(unsigned long);
  70        xfer.bits_per_word = 24;
  71
  72        spi_message_init(&msg);
  73        spi_message_add_tail(&xfer, &msg);
  74
  75        if (spi == NULL)
  76                return 0;
  77
  78        ret = spi_sync(spi, &msg);
  79        if (ret == 0)
  80                *data = (u8) (rx_buf & 0xFF);
  81        return ret;
  82}
  83
  84static int tps65912_spi_probe(struct spi_device *spi)
  85{
  86        struct tps65912 *tps65912;
  87
  88        tps65912 = devm_kzalloc(&spi->dev,
  89                                sizeof(struct tps65912), GFP_KERNEL);
  90        if (tps65912 == NULL)
  91                return -ENOMEM;
  92
  93        tps65912->dev = &spi->dev;
  94        tps65912->control_data = spi;
  95        tps65912->read = tps65912_spi_read;
  96        tps65912->write = tps65912_spi_write;
  97
  98        spi_set_drvdata(spi, tps65912);
  99
 100        return tps65912_device_init(tps65912);
 101}
 102
 103static int tps65912_spi_remove(struct spi_device *spi)
 104{
 105        struct tps65912 *tps65912 = spi_get_drvdata(spi);
 106
 107        tps65912_device_exit(tps65912);
 108
 109        return 0;
 110}
 111
 112static struct spi_driver tps65912_spi_driver = {
 113        .driver = {
 114                .name = "tps65912",
 115                .owner = THIS_MODULE,
 116        },
 117        .probe  = tps65912_spi_probe,
 118        .remove = tps65912_spi_remove,
 119};
 120
 121static int __init tps65912_spi_init(void)
 122{
 123        int ret;
 124
 125        ret = spi_register_driver(&tps65912_spi_driver);
 126        if (ret != 0)
 127                pr_err("Failed to register TPS65912 SPI driver: %d\n", ret);
 128
 129        return 0;
 130}
 131/* init early so consumer devices can complete system boot */
 132subsys_initcall(tps65912_spi_init);
 133
 134static void __exit tps65912_spi_exit(void)
 135{
 136        spi_unregister_driver(&tps65912_spi_driver);
 137}
 138module_exit(tps65912_spi_exit);
 139
 140MODULE_AUTHOR("Margarita Olaya  <magi@slimlogic.co.uk>");
 141MODULE_DESCRIPTION("SPI support for TPS65912 chip family mfd");
 142MODULE_LICENSE("GPL");
 143
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