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
  17 enum mop500_uib {
  18         STUIB,
  19         U8500UIB,
  20 };
  21
  22 struct uib {
  23         const char *name;
  24         const char *option;
  25         void (*init)(void);
  26 };
  27
  28 static struct __initdata uib mop500_uibs[] = {
  29         [STUIB] = {
  30                 .name   = "ST-UIB",
  31                 .option = "stuib",
  32                 .init   = mop500_stuib_init,
  33         },
  34         [U8500UIB] = {
  35                 .name   = "U8500-UIB",
  36                 .option = "u8500uib",
  37                 .init   = mop500_u8500uib_init,
  38         },
  39 };
  40
  41 static struct uib *mop500_uib;
  42
  43 static int __init mop500_uib_setup(char *str)
  44 {
  45         int i;
  46
  47         for (i = 0; i < ARRAY_SIZE(mop500_uibs); i++) {
  48                 struct uib *uib = &mop500_uibs[i];
  49
  50                 if (!strcmp(str, uib->option)) {
  51                         mop500_uib = uib;
  52                         break;
  53                 }
  54         }
  55
  56         if (i == ARRAY_SIZE(mop500_uibs))
  57                 pr_err("invalid uib= option (%s)\n", str);
  58
  59         return 1;
  60 }
  61 __setup("uib=", mop500_uib_setup);
  62
  63 /*
  64  * The UIBs are detected after the I2C host controllers are registered, so
  65  * i2c_register_board_info() can't be used.
  66  */
  67 void mop500_uib_i2c_add(int busnum, struct i2c_board_info *info,
  68                 unsigned n)
  69 {
  70         struct i2c_adapter *adap;
  71         struct i2c_client *client;
  72         int i;
  73
  74         adap = i2c_get_adapter(busnum);
  75         if (!adap) {
  76                 pr_err("failed to get adapter i2c%d\n", busnum);
  77                 return;
  78         }
  79
  80         for (i = 0; i < n; i++) {
  81                 client = i2c_new_device(adap, &info[i]);
  82                 if (!client)
  83                         pr_err("failed to register %s to i2c%d\n",
  84                                         info[i].type, busnum);
  85         }
  86
  87         i2c_put_adapter(adap);
  88 }
  89
  90 static void __init __mop500_uib_init(struct uib *uib, const char *why)
  91 {
  92         pr_info("%s (%s)\n", uib->name, why);
  93         uib->init();
  94 }
  95
  96 /*
  97  * Detect the UIB attached based on the presence or absence of i2c devices.
  98  */
  99 static int __init mop500_uib_init(void)
 100 {
 101         struct uib *uib = mop500_uib;
 102         struct i2c_adapter *i2c0;
 103         int ret;
 104
 105         if (!cpu_is_u8500())
 106                 return -ENODEV;
 107
 108         if (uib) {
 109                 __mop500_uib_init(uib, "from uib= boot argument");
 110                 return 0;
 111         }
 112
 113         i2c0 = i2c_get_adapter(0);
 114         if (!i2c0) {
 115                 __mop500_uib_init(&mop500_uibs[STUIB],
 116                                 "fallback, could not get i2c0");
 117                 return -ENODEV;
 118         }
 119
 120         /* U8500-UIB has the TC35893 at 0x44 on I2C0, the ST-UIB doesn't. */
 121         ret = i2c_smbus_xfer(i2c0, 0x44, 0, I2C_SMBUS_WRITE, 0,
 122                         I2C_SMBUS_QUICK, NULL);
 123         i2c_put_adapter(i2c0);
 124
 125         if (ret == 0)
 126                 uib = &mop500_uibs[U8500UIB];
 127         else
 128                 uib = &mop500_uibs[STUIB];
 129
 130         __mop500_uib_init(uib, "detected");
 131
 132         return 0;
 133 }
 134
 135 module_init(mop500_uib_init);