1 /* 2 * i2c driver for Freescale mx31 3 * 4 * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de> 5 * 6 * See file CREDITS for list of people who contributed to this 7 * project. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License as 11 * published by the Free Software Foundation; either version 2 of 12 * the License, or (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 22 * MA 02111-1307 USA 23 */ 24 25 #include <common.h> 26 27 #if defined(CONFIG_HARD_I2C) 28 29 #include <asm/arch/mx31.h> 30 #include <asm/arch/mx31-regs.h> 31 32 #define IADR 0x00 33 #define IFDR 0x04 34 #define I2CR 0x08 35 #define I2SR 0x0c 36 #define I2DR 0x10 37 38 #define I2CR_IEN (1 << 7) 39 #define I2CR_IIEN (1 << 6) 40 #define I2CR_MSTA (1 << 5) 41 #define I2CR_MTX (1 << 4) 42 #define I2CR_TX_NO_AK (1 << 3) 43 #define I2CR_RSTA (1 << 2) 44 45 #define I2SR_ICF (1 << 7) 46 #define I2SR_IBB (1 << 5) 47 #define I2SR_IIF (1 << 1) 48 #define I2SR_RX_NO_AK (1 << 0) 49 50 #ifdef CFG_I2C_MX31_PORT1 51 #define I2C_BASE 0x43f80000 52 #elif defined (CFG_I2C_MX31_PORT2) 53 #define I2C_BASE 0x43f98000 54 #elif defined (CFG_I2C_MX31_PORT3) 55 #define I2C_BASE 0x43f84000 56 #else 57 #error "define CFG_I2C_MX31_PORTx to use the mx31 I2C driver" 58 #endif 59 60 #ifdef DEBUG 61 #define DPRINTF(args...) printf(args) 62 #else 63 #define DPRINTF(args...) 64 #endif 65 66 static u16 div[] = { 30, 32, 36, 42, 48, 52, 60, 72, 80, 88, 104, 128, 144, 67 160, 192, 240, 288, 320, 384, 480, 576, 640, 768, 960, 68 1152, 1280, 1536, 1920, 2304, 2560, 3072, 3840}; 69 70 void i2c_init(int speed, int unused) 71 { 72 int freq = mx31_get_ipg_clk(); 73 int i; 74 75 for (i = 0; i < 0x1f; i++) 76 if (freq / div[i] <= speed) 77 break; 78 79 DPRINTF("%s: speed: %d\n",__FUNCTION__, speed); 80 81 __REG16(I2C_BASE + I2CR) = 0; /* Reset module */ 82 __REG16(I2C_BASE + IFDR) = i; 83 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 84 __REG16(I2C_BASE + I2SR) = 0; 85 } 86 87 static int wait_busy(void) 88 { 89 int timeout = 10000; 90 91 while (!(__REG16(I2C_BASE + I2SR) & I2SR_IIF) && --timeout) 92 udelay(1); 93 __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */ 94 95 return timeout; 96 } 97 98 static int tx_byte(u8 byte) 99 { 100 __REG16(I2C_BASE + I2DR) = byte; 101 102 if (!wait_busy() || __REG16(I2C_BASE + I2SR) & I2SR_RX_NO_AK) 103 return -1; 104 return 0; 105 } 106 107 static int rx_byte(void) 108 { 109 if (!wait_busy()) 110 return -1; 111 112 return __REG16(I2C_BASE + I2DR); 113 } 114 115 int i2c_probe(uchar chip) 116 { 117 int ret; 118 119 __REG16(I2C_BASE + I2CR) = 0; /* Reset module */ 120 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 121 122 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX; 123 ret = tx_byte(chip << 1); 124 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MTX; 125 126 return ret; 127 } 128 129 static int i2c_addr(uchar chip, uint addr, int alen) 130 { 131 __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */ 132 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX; 133 134 if (tx_byte(chip << 1)) 135 return -1; 136 137 while (alen--) 138 if (tx_byte((addr >> (alen * 8)) & 0xff)) 139 return -1; 140 return 0; 141 } 142 143 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) 144 { 145 int timeout = 10000; 146 int ret; 147 148 DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len); 149 150 if (i2c_addr(chip, addr, alen)) { 151 printf("i2c_addr failed\n"); 152 return -1; 153 } 154 155 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX | I2CR_RSTA; 156 157 if (tx_byte(chip << 1 | 1)) 158 return -1; 159 160 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | ((len == 1) ? I2CR_TX_NO_AK : 0); 161 162 ret = __REG16(I2C_BASE + I2DR); 163 164 while (len--) { 165 if ((ret = rx_byte()) < 0) 166 return -1; 167 *buf++ = ret; 168 if (len <= 1) 169 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_TX_NO_AK; 170 } 171 172 wait_busy(); 173 174 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 175 176 while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout) 177 udelay(1); 178 179 return 0; 180 } 181 182 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len) 183 { 184 int timeout = 10000; 185 DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len); 186 187 if (i2c_addr(chip, addr, alen)) 188 return -1; 189 190 while (len--) 191 if (tx_byte(*buf++)) 192 return -1; 193 194 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 195 196 while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout) 197 udelay(1); 198 199 return 0; 200 } 201 202 #endif /* CONFIG_HARD_I2C */ 203