1 /* 2 * (C) Copyright 2008 3 * Heiko Schocher, DENX Software Engineering, hs@denx.de. 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 */ 23 24 #include <common.h> 25 #include <mpc8260.h> 26 #include <ioports.h> 27 #include <malloc.h> 28 29 #if defined(CONFIG_OF_BOARD_SETUP) && defined(CONFIG_OF_LIBFDT) 30 #include <libfdt.h> 31 #endif 32 33 #if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C) 34 #include <i2c.h> 35 #endif 36 37 extern int i2c_soft_read_pin (void); 38 39 #if defined(CFG_I2C_INIT_BOARD) 40 #define DELAY_ABORT_SEQ 62 41 #define DELAY_HALF_PERIOD (500 / (CFG_I2C_SPEED / 1000)) 42 43 #if defined(CONFIG_MGCOGE) 44 #define SDA_MASK 0x00010000 45 #define SCL_MASK 0x00020000 46 static void set_pin (int state, unsigned long mask) 47 { 48 volatile ioport_t *iop = ioport_addr ((immap_t *)CFG_IMMR, 3); 49 50 if (state) 51 iop->pdat |= (mask); 52 else 53 iop->pdat &= ~(mask); 54 55 iop->pdir |= (mask); 56 } 57 58 static int get_pin (unsigned long mask) 59 { 60 volatile ioport_t *iop = ioport_addr ((immap_t *)CFG_IMMR, 3); 61 62 iop->pdir &= ~(mask); 63 return (0 != (iop->pdat & (mask))); 64 } 65 66 static void set_sda (int state) 67 { 68 set_pin (state, SDA_MASK); 69 } 70 71 static void set_scl (int state) 72 { 73 set_pin (state, SCL_MASK); 74 } 75 76 static int get_sda (void) 77 { 78 return get_pin (SDA_MASK); 79 } 80 81 static int get_scl (void) 82 { 83 return get_pin (SCL_MASK); 84 } 85 86 #if defined(CONFIG_HARD_I2C) 87 static void setports (int gpio) 88 { 89 volatile ioport_t *iop = ioport_addr ((immap_t *)CFG_IMMR, 3); 90 91 if (gpio) { 92 iop->ppar &= ~(SDA_MASK | SCL_MASK); 93 iop->podr &= ~(SDA_MASK | SCL_MASK); 94 } else { 95 iop->ppar |= (SDA_MASK | SCL_MASK); 96 iop->pdir &= ~(SDA_MASK | SCL_MASK); 97 iop->podr |= (SDA_MASK | SCL_MASK); 98 } 99 } 100 #endif 101 #endif 102 103 #if defined(CONFIG_MGSUVD) 104 static void set_sda (int state) 105 { 106 I2C_SDA(state); 107 } 108 109 static void set_scl (int state) 110 { 111 I2C_SCL(state); 112 } 113 114 static int get_sda (void) 115 { 116 return i2c_soft_read_pin (); 117 } 118 119 static int get_scl (void) 120 { 121 int val; 122 123 *(unsigned short *)(I2C_BASE_DIR) &= ~SCL_CONF; 124 udelay (1); 125 val = *(unsigned char *)(I2C_BASE_PORT); 126 127 return ((val & SCL_BIT) == SCL_BIT); 128 } 129 130 #endif 131 132 static void writeStartSeq (void) 133 { 134 set_sda (1); 135 udelay (DELAY_HALF_PERIOD); 136 set_scl (1); 137 udelay (DELAY_HALF_PERIOD); 138 set_sda (0); 139 udelay (DELAY_HALF_PERIOD); 140 set_scl (0); 141 udelay (DELAY_HALF_PERIOD); 142 } 143 144 /* I2C is a synchronous protocol and resets of the processor in the middle 145 of an access can block the I2C Bus until a powerdown of the full unit is 146 done. This function toggles the SCL until the SCL and SCA line are 147 released, but max. 16 times, after this a I2C start-sequence is sent. 148 This I2C Deblocking mechanism was developed by Keymile in association 149 with Anatech and Atmel in 1998. 150 */ 151 static int i2c_make_abort (void) 152 { 153 int scl_state = 0; 154 int sda_state = 0; 155 int i = 0; 156 int ret = 0; 157 158 if (!get_sda ()) { 159 ret = -1; 160 while (i < 16) { 161 i++; 162 set_scl (0); 163 udelay (DELAY_ABORT_SEQ); 164 set_scl (1); 165 udelay (DELAY_ABORT_SEQ); 166 scl_state = get_scl (); 167 sda_state = get_sda (); 168 if (scl_state && sda_state) { 169 ret = 0; 170 break; 171 } 172 } 173 } 174 if (ret == 0) { 175 for (i =0; i < 5; i++) { 176 writeStartSeq (); 177 } 178 } 179 get_sda (); 180 return ret; 181 } 182 183 /** 184 * i2c_init_board - reset i2c bus. When the board is powercycled during a 185 * bus transfer it might hang; for details see doc/I2C_Edge_Conditions. 186 */ 187 void i2c_init_board(void) 188 { 189 #if defined(CONFIG_HARD_I2C) 190 volatile immap_t *immap = (immap_t *)CFG_IMMR ; 191 volatile i2c8260_t *i2c = (i2c8260_t *)&immap->im_i2c; 192 193 /* disable I2C controller first, otherwhise it thinks we want to */ 194 /* talk to the slave port... */ 195 i2c->i2c_i2mod &= ~0x01; 196 197 /* Set the PortPins to GPIO */ 198 setports (1); 199 #endif 200 201 /* Now run the AbortSequence() */ 202 i2c_make_abort (); 203 204 #if defined(CONFIG_HARD_I2C) 205 /* Set the PortPins back to use for I2C */ 206 setports (0); 207 #endif 208 } 209 #endif 210