arch/arm/cpu/arm926ejs/davinci/pinmux.c

   1 /*
   2  * DaVinci pinmux functions.
   3  *
   4  * Copyright (C) 2009 Nick Thompson, GE Fanuc Ltd, <nick.thompson@gefanuc.com>
   5  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
   6  * Copyright (C) 2008 Lyrtech <www.lyrtech.com>
   7  * Copyright (C) 2004 Texas Instruments.
   8  *
   9  * See file CREDITS for list of people who contributed to this
  10  * project.
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  25  */
  26
  27 #include <common.h>
  28 #include <asm/arch/hardware.h>
  29 #include <asm/io.h>
  30 #include <asm/arch/davinci_misc.h>
  31
  32 /*
  33  * Change the setting of a pin multiplexer field.
  34  *
  35  * Takes an array of pinmux settings similar to:
  36  *
  37  * struct pinmux_config uart_pins[] = {
  38  *      { &davinci_syscfg_regs->pinmux[8], 2, 7 },
  39  *      { &davinci_syscfg_regs->pinmux[9], 2, 0 }
  40  * };
  41  *
  42  * Stepping through the array, each pinmux[n] register has the given value
  43  * set in the pin mux field specified.
  44  *
  45  * The number of pins in the array must be passed (ARRAY_SIZE can provide
  46  * this value conveniently).
  47  *
  48  * Returns 0 if all field numbers and values are in the correct range,
  49  * else returns -1.
  50  */
  51 int davinci_configure_pin_mux(const struct pinmux_config *pins,
  52                               const int n_pins)
  53 {
  54         int i;
  55
  56         /* check for invalid pinmux values */
  57         for (i = 0; i < n_pins; i++) {
  58                 if (pins[i].field >= PIN_MUX_NUM_FIELDS ||
  59                     (pins[i].value & ~PIN_MUX_FIELD_MASK) != 0)
  60                         return -1;
  61         }
  62
  63         /* configure the pinmuxes */
  64         for (i = 0; i < n_pins; i++) {
  65                 const int offset = pins[i].field * PIN_MUX_FIELD_SIZE;
  66                 const unsigned int value = pins[i].value << offset;
  67                 const unsigned int mask = PIN_MUX_FIELD_MASK << offset;
  68                 const dv_reg *mux = pins[i].mux;
  69
  70                 writel(value | (readl(mux) & (~mask)), mux);
  71         }
  72
  73         return 0;
  74 }
  75
  76 /*
  77  * Configure multiple pinmux resources.
  78  *
  79  * Takes an pinmux_resource array of pinmux_config and pin counts:
  80  *
  81  * const struct pinmux_resource pinmuxes[] = {
  82  *      PINMUX_ITEM(uart_pins),
  83  *      PINMUX_ITEM(i2c_pins),
  84  * };
  85  *
  86  * The number of items in the array must be passed (ARRAY_SIZE can provide
  87  * this value conveniently).
  88  *
  89  * Each item entry is configured in the defined order. If configuration
  90  * of any item fails, -1 is returned and none of the following items are
  91  * configured. On success, 0 is returned.
  92  */
  93 int davinci_configure_pin_mux_items(const struct pinmux_resource *item,
  94                                     const int n_items)
  95 {
  96         int i;
  97
  98         for (i = 0; i < n_items; i++) {
  99                 if (davinci_configure_pin_mux(item[i].pins,
 100                                               item[i].n_pins) != 0)
 101                         return -1;
 102         }
 103
 104         return 0;
 105 }