arch/arm/mach-ux500/board-mop500-uib.c

   1 /*
   2  * Copyright (C) ST-Ericsson SA 2010
   3  *
   4  * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
   5  * License terms: GNU General Public License (GPL), version 2
   6  */
   7
   8 #define pr_fmt(fmt)     "mop500-uib: " fmt
   9
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/i2c.h>
  13
  14 #include <mach/hardware.h>
  15 #include "board-mop500.h"
  16 #include "id.h"
  17
  18 enum mop500_uib {
  19         STUIB,
  20         U8500UIB,
  21 };
  22
  23 struct uib {
  24         const char *name;
  25         const char *option;
  26         void (*init)(void);
  27 };
  28
  29 static struct uib __initdata mop500_uibs[] = {
  30         [STUIB] = {
  31                 .name   = "ST-UIB",
  32                 .option = "stuib",
  33                 .init   = mop500_stuib_init,
  34         },
  35         [U8500UIB] = {
  36                 .name   = "U8500-UIB",
  37                 .option = "u8500uib",
  38                 .init   = mop500_u8500uib_init,
  39         },
  40 };
  41
  42 static struct uib *mop500_uib;
  43
  44 static int __init mop500_uib_setup(char *str)
  45 {
  46         int i;
  47
  48         for (i = 0; i < ARRAY_SIZE(mop500_uibs); i++) {
  49                 struct uib *uib = &mop500_uibs[i];
  50
  51                 if (!strcmp(str, uib->option)) {
  52                         mop500_uib = uib;
  53                         break;
  54                 }
  55         }
  56
  57         if (i == ARRAY_SIZE(mop500_uibs))
  58                 pr_err("invalid uib= option (%s)\n", str);
  59
  60         return 1;
  61 }
  62 __setup("uib=", mop500_uib_setup);
  63
  64 /*
  65  * The UIBs are detected after the I2C host controllers are registered, so
  66  * i2c_register_board_info() can't be used.
  67  */
  68 void mop500_uib_i2c_add(int busnum, struct i2c_board_info *info,
  69                 unsigned n)
  70 {
  71         struct i2c_adapter *adap;
  72         struct i2c_client *client;
  73         int i;
  74
  75         adap = i2c_get_adapter(busnum);
  76         if (!adap) {
  77                 pr_err("failed to get adapter i2c%d\n", busnum);
  78                 return;
  79         }
  80
  81         for (i = 0; i < n; i++) {
  82                 client = i2c_new_device(adap, &info[i]);
  83                 if (!client)
  84                         pr_err("failed to register %s to i2c%d\n",
  85                                         info[i].type, busnum);
  86         }
  87
  88         i2c_put_adapter(adap);
  89 }
  90
  91 static void __init __mop500_uib_init(struct uib *uib, const char *why)
  92 {
  93         pr_info("%s (%s)\n", uib->name, why);
  94         uib->init();
  95 }
  96
  97 /*
  98  * Detect the UIB attached based on the presence or absence of i2c devices.
  99  */
 100 int __init mop500_uib_init(void)
 101 {
 102         struct uib *uib = mop500_uib;
 103         struct i2c_adapter *i2c0;
 104         int ret;
 105
 106         if (!cpu_is_u8500_family())
 107                 return -ENODEV;
 108
 109         if (uib) {
 110                 __mop500_uib_init(uib, "from uib= boot argument");
 111                 return 0;
 112         }
 113
 114         i2c0 = i2c_get_adapter(0);
 115         if (!i2c0) {
 116                 __mop500_uib_init(&mop500_uibs[STUIB],
 117                                 "fallback, could not get i2c0");
 118                 return -ENODEV;
 119         }
 120
 121         /* U8500-UIB has the TC35893 at 0x44 on I2C0, the ST-UIB doesn't. */
 122         ret = i2c_smbus_xfer(i2c0, 0x44, 0, I2C_SMBUS_WRITE, 0,
 123                         I2C_SMBUS_QUICK, NULL);
 124         i2c_put_adapter(i2c0);
 125
 126         if (ret == 0)
 127                 uib = &mop500_uibs[U8500UIB];
 128         else
 129                 uib = &mop500_uibs[STUIB];
 130
 131         __mop500_uib_init(uib, "detected");
 132
 133         return 0;
 134 }