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 CONFIG_SYS_I2C_MX31_PORT1 51 #define I2C_BASE 0x43f80000 52 #define I2C_CLK_OFFSET 26 53 #elif defined (CONFIG_SYS_I2C_MX31_PORT2) 54 #define I2C_BASE 0x43f98000 55 #define I2C_CLK_OFFSET 28 56 #elif defined (CONFIG_SYS_I2C_MX31_PORT3) 57 #define I2C_BASE 0x43f84000 58 #define I2C_CLK_OFFSET 30 59 #else 60 #error "define CONFIG_SYS_I2C_MX31_PORTx to use the mx31 I2C driver" 61 #endif 62 63 #ifdef DEBUG 64 #define DPRINTF(args...) printf(args) 65 #else 66 #define DPRINTF(args...) 67 #endif 68 69 static u16 div[] = { 30, 32, 36, 42, 48, 52, 60, 72, 80, 88, 104, 128, 144, 70 160, 192, 240, 288, 320, 384, 480, 576, 640, 768, 960, 71 1152, 1280, 1536, 1920, 2304, 2560, 3072, 3840}; 72 73 void i2c_init(int speed, int unused) 74 { 75 int freq = mx31_get_ipg_clk(); 76 int i; 77 78 /* start the required I2C clock */ 79 __REG(CCM_CGR0) = __REG(CCM_CGR0) | (3 << I2C_CLK_OFFSET); 80 81 for (i = 0; i < 0x1f; i++) 82 if (freq / div[i] <= speed) 83 break; 84 85 DPRINTF("%s: speed: %d\n",__FUNCTION__, speed); 86 87 __REG16(I2C_BASE + I2CR) = 0; /* Reset module */ 88 __REG16(I2C_BASE + IFDR) = i; 89 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 90 __REG16(I2C_BASE + I2SR) = 0; 91 } 92 93 static int wait_busy(void) 94 { 95 int timeout = 10000; 96 97 while (!(__REG16(I2C_BASE + I2SR) & I2SR_IIF) && --timeout) 98 udelay(1); 99 __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */ 100 101 return timeout; 102 } 103 104 static int tx_byte(u8 byte) 105 { 106 __REG16(I2C_BASE + I2DR) = byte; 107 108 if (!wait_busy() || __REG16(I2C_BASE + I2SR) & I2SR_RX_NO_AK) 109 return -1; 110 return 0; 111 } 112 113 static int rx_byte(void) 114 { 115 if (!wait_busy()) 116 return -1; 117 118 return __REG16(I2C_BASE + I2DR); 119 } 120 121 int i2c_probe(uchar chip) 122 { 123 int ret; 124 125 __REG16(I2C_BASE + I2CR) = 0; /* Reset module */ 126 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 127 128 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX; 129 ret = tx_byte(chip << 1); 130 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MTX; 131 132 return ret; 133 } 134 135 static int i2c_addr(uchar chip, uint addr, int alen) 136 { 137 __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */ 138 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX; 139 140 if (tx_byte(chip << 1)) 141 return -1; 142 143 while (alen--) 144 if (tx_byte((addr >> (alen * 8)) & 0xff)) 145 return -1; 146 return 0; 147 } 148 149 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) 150 { 151 int timeout = 10000; 152 int ret; 153 154 DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len); 155 156 if (i2c_addr(chip, addr, alen)) { 157 printf("i2c_addr failed\n"); 158 return -1; 159 } 160 161 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX | I2CR_RSTA; 162 163 if (tx_byte(chip << 1 | 1)) 164 return -1; 165 166 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | ((len == 1) ? I2CR_TX_NO_AK : 0); 167 168 ret = __REG16(I2C_BASE + I2DR); 169 170 while (len--) { 171 if ((ret = rx_byte()) < 0) 172 return -1; 173 *buf++ = ret; 174 if (len <= 1) 175 __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_TX_NO_AK; 176 } 177 178 wait_busy(); 179 180 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 181 182 while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout) 183 udelay(1); 184 185 return 0; 186 } 187 188 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len) 189 { 190 int timeout = 10000; 191 DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len); 192 193 if (i2c_addr(chip, addr, alen)) 194 return -1; 195 196 while (len--) 197 if (tx_byte(*buf++)) 198 return -1; 199 200 __REG16(I2C_BASE + I2CR) = I2CR_IEN; 201 202 while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout) 203 udelay(1); 204 205 return 0; 206 } 207 208 #endif /* CONFIG_HARD_I2C */ 209