drivers/mfd/tps65912-spi.c

   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
  25 static 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
  52 static 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
  84 static int __devinit tps65912_spi_probe(struct spi_device *spi)
  85 {
  86         struct tps65912 *tps65912;
  87
  88         tps65912 = kzalloc(sizeof(struct tps65912), GFP_KERNEL);
  89         if (tps65912 == NULL)
  90                 return -ENOMEM;
  91
  92         tps65912->dev = &spi->dev;
  93         tps65912->control_data = spi;
  94         tps65912->read = tps65912_spi_read;
  95         tps65912->write = tps65912_spi_write;
  96
  97         spi_set_drvdata(spi, tps65912);
  98
  99         return tps65912_device_init(tps65912);
 100 }
 101
 102 static int __devexit tps65912_spi_remove(struct spi_device *spi)
 103 {
 104         struct tps65912 *tps65912 = spi_get_drvdata(spi);
 105
 106         tps65912_device_exit(tps65912);
 107
 108         return 0;
 109 }
 110
 111 static struct spi_driver tps65912_spi_driver = {
 112         .driver = {
 113                 .name = "tps65912",
 114                 .bus = &spi_bus_type,
 115                 .owner = THIS_MODULE,
 116         },
 117         .probe  = tps65912_spi_probe,
 118         .remove = __devexit_p(tps65912_spi_remove),
 119 };
 120
 121 static 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 */
 132 subsys_initcall(tps65912_spi_init);
 133
 134 static void __exit tps65912_spi_exit(void)
 135 {
 136         spi_unregister_driver(&tps65912_spi_driver);
 137 }
 138 module_exit(tps65912_spi_exit);
 139
 140 MODULE_AUTHOR("Margarita Olaya  <magi@slimlogic.co.uk>");
 141 MODULE_DESCRIPTION("SPI support for TPS65912 chip family mfd");
 142 MODULE_LICENSE("GPL");