1 /* 2 * i2c driver for Freescale i.MX series 3 * 4 * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de> 5 * (c) 2011 Marek Vasut <marek.vasut@gmail.com> 6 * 7 * Based on i2c-imx.c from linux kernel: 8 * Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de> 9 * Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de> 10 * Copyright (C) 2007 RightHand Technologies, Inc. 11 * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt> 12 * 13 * 14 * See file CREDITS for list of people who contributed to this 15 * project. 16 * 17 * This program is free software; you can redistribute it and/or 18 * modify it under the terms of the GNU General Public License as 19 * published by the Free Software Foundation; either version 2 of 20 * the License, or (at your option) any later version. 21 * 22 * This program is distributed in the hope that it will be useful, 23 * but WITHOUT ANY WARRANTY; without even the implied warranty of 24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 25 * GNU General Public License for more details. 26 * 27 * You should have received a copy of the GNU General Public License 28 * along with this program; if not, write to the Free Software 29 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 30 * MA 02111-1307 USA 31 */ 32 33 #include <common.h> 34 #include <asm/arch/clock.h> 35 #include <asm/arch/imx-regs.h> 36 #include <asm/errno.h> 37 #include <asm/io.h> 38 #include <i2c.h> 39 #include <watchdog.h> 40 41 struct mxc_i2c_regs { 42 uint32_t iadr; 43 uint32_t ifdr; 44 uint32_t i2cr; 45 uint32_t i2sr; 46 uint32_t i2dr; 47 }; 48 49 #define I2CR_IEN (1 << 7) 50 #define I2CR_IIEN (1 << 6) 51 #define I2CR_MSTA (1 << 5) 52 #define I2CR_MTX (1 << 4) 53 #define I2CR_TX_NO_AK (1 << 3) 54 #define I2CR_RSTA (1 << 2) 55 56 #define I2SR_ICF (1 << 7) 57 #define I2SR_IBB (1 << 5) 58 #define I2SR_IAL (1 << 4) 59 #define I2SR_IIF (1 << 1) 60 #define I2SR_RX_NO_AK (1 << 0) 61 62 #ifdef CONFIG_SYS_I2C_BASE 63 #define I2C_BASE CONFIG_SYS_I2C_BASE 64 #else 65 #error "define CONFIG_SYS_I2C_BASE to use the mxc_i2c driver" 66 #endif 67 68 static u16 i2c_clk_div[50][2] = { 69 { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 }, 70 { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 }, 71 { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 }, 72 { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B }, 73 { 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A }, 74 { 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 }, 75 { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 }, 76 { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 }, 77 { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 }, 78 { 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B }, 79 { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E }, 80 { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D }, 81 { 3072, 0x1E }, { 3840, 0x1F } 82 }; 83 84 /* 85 * Calculate and set proper clock divider 86 */ 87 static uint8_t i2c_imx_get_clk(unsigned int rate) 88 { 89 unsigned int i2c_clk_rate; 90 unsigned int div; 91 u8 clk_div; 92 93 #if defined(CONFIG_MX31) 94 struct clock_control_regs *sc_regs = 95 (struct clock_control_regs *)CCM_BASE; 96 97 /* start the required I2C clock */ 98 writel(readl(&sc_regs->cgr0) | (3 << CONFIG_SYS_I2C_CLK_OFFSET), 99 &sc_regs->cgr0); 100 #endif 101 102 /* Divider value calculation */ 103 i2c_clk_rate = mxc_get_clock(MXC_IPG_PERCLK); 104 div = (i2c_clk_rate + rate - 1) / rate; 105 if (div < i2c_clk_div[0][0]) 106 clk_div = 0; 107 else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0]) 108 clk_div = ARRAY_SIZE(i2c_clk_div) - 1; 109 else 110 for (clk_div = 0; i2c_clk_div[clk_div][0] < div; clk_div++) 111 ; 112 113 /* Store divider value */ 114 return clk_div; 115 } 116 117 /* 118 * Init I2C Bus 119 */ 120 void i2c_init(int speed, int unused) 121 { 122 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; 123 u8 clk_idx = i2c_imx_get_clk(speed); 124 u8 idx = i2c_clk_div[clk_idx][1]; 125 126 /* Store divider value */ 127 writeb(idx, &i2c_regs->ifdr); 128 129 /* Reset module */ 130 writeb(0, &i2c_regs->i2cr); 131 writeb(0, &i2c_regs->i2sr); 132 } 133 134 /* 135 * Set I2C Speed 136 */ 137 int i2c_set_bus_speed(unsigned int speed) 138 { 139 i2c_init(speed, 0); 140 return 0; 141 } 142 143 /* 144 * Get I2C Speed 145 */ 146 unsigned int i2c_get_bus_speed(void) 147 { 148 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; 149 u8 clk_idx = readb(&i2c_regs->ifdr); 150 u8 clk_div; 151 152 for (clk_div = 0; i2c_clk_div[clk_div][1] != clk_idx; clk_div++) 153 ; 154 155 return mxc_get_clock(MXC_IPG_PERCLK) / i2c_clk_div[clk_div][0]; 156 } 157 158 #define ST_BUS_IDLE (0 | (I2SR_IBB << 8)) 159 #define ST_BUS_BUSY (I2SR_IBB | (I2SR_IBB << 8)) 160 #define ST_IIF (I2SR_IIF | (I2SR_IIF << 8)) 161 162 static int wait_for_sr_state(struct mxc_i2c_regs *i2c_regs, unsigned state) 163 { 164 unsigned sr; 165 ulong elapsed; 166 ulong start_time = get_timer(0); 167 for (;;) { 168 sr = readb(&i2c_regs->i2sr); 169 if (sr & I2SR_IAL) { 170 writeb(sr & ~I2SR_IAL, &i2c_regs->i2sr); 171 printf("%s: Arbitration lost sr=%x cr=%x state=%x\n", 172 __func__, sr, readb(&i2c_regs->i2cr), state); 173 return -ERESTART; 174 } 175 if ((sr & (state >> 8)) == (unsigned char)state) 176 return sr; 177 WATCHDOG_RESET(); 178 elapsed = get_timer(start_time); 179 if (elapsed > (CONFIG_SYS_HZ / 10)) /* .1 seconds */ 180 break; 181 } 182 printf("%s: failed sr=%x cr=%x state=%x\n", __func__, 183 sr, readb(&i2c_regs->i2cr), state); 184 return -ETIMEDOUT; 185 } 186 187 static int tx_byte(struct mxc_i2c_regs *i2c_regs, u8 byte) 188 { 189 int ret; 190 191 writeb(0, &i2c_regs->i2sr); 192 writeb(byte, &i2c_regs->i2dr); 193 ret = wait_for_sr_state(i2c_regs, ST_IIF); 194 if (ret < 0) 195 return ret; 196 if (ret & I2SR_RX_NO_AK) 197 return -ENODEV; 198 return 0; 199 } 200 201 /* 202 * Stop I2C transaction 203 */ 204 void i2c_imx_stop(void) 205 { 206 int ret; 207 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; 208 unsigned int temp = readb(&i2c_regs->i2cr); 209 210 temp &= ~(I2CR_MSTA | I2CR_MTX); 211 writeb(temp, &i2c_regs->i2cr); 212 ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); 213 if (ret < 0) 214 printf("%s:trigger stop failed\n", __func__); 215 } 216 217 /* 218 * Send start signal, chip address and 219 * write register address 220 */ 221 static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs, 222 uchar chip, uint addr, int alen) 223 { 224 unsigned int temp; 225 int ret; 226 227 /* Enable I2C controller */ 228 if (!(readb(&i2c_regs->i2cr) & I2CR_IEN)) { 229 writeb(I2CR_IEN, &i2c_regs->i2cr); 230 /* Wait for controller to be stable */ 231 udelay(50); 232 } 233 if (readb(&i2c_regs->iadr) == (chip << 1)) 234 writeb((chip << 1) ^ 2, &i2c_regs->iadr); 235 writeb(0, &i2c_regs->i2sr); 236 ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE); 237 if (ret < 0) 238 goto exit; 239 240 /* Start I2C transaction */ 241 temp = readb(&i2c_regs->i2cr); 242 temp |= I2CR_MSTA; 243 writeb(temp, &i2c_regs->i2cr); 244 245 ret = wait_for_sr_state(i2c_regs, ST_BUS_BUSY); 246 if (ret < 0) 247 goto exit; 248 249 temp |= I2CR_MTX | I2CR_TX_NO_AK; 250 writeb(temp, &i2c_regs->i2cr); 251 252 /* write slave address */ 253 ret = tx_byte(i2c_regs, chip << 1); 254 if (ret < 0) 255 goto exit; 256 257 while (alen--) { 258 ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff); 259 if (ret < 0) 260 goto exit; 261 } 262 return 0; 263 exit: 264 i2c_imx_stop(); 265 /* Disable I2C controller */ 266 writeb(0, &i2c_regs->i2cr); 267 return ret; 268 } 269 270 /* 271 * Read data from I2C device 272 */ 273 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) 274 { 275 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; 276 int ret; 277 unsigned int temp; 278 int i; 279 280 ret = i2c_init_transfer(i2c_regs, chip, addr, alen); 281 if (ret < 0) 282 return ret; 283 284 temp = readb(&i2c_regs->i2cr); 285 temp |= I2CR_RSTA; 286 writeb(temp, &i2c_regs->i2cr); 287 288 ret = tx_byte(i2c_regs, (chip << 1) | 1); 289 if (ret < 0) { 290 i2c_imx_stop(); 291 return ret; 292 } 293 294 /* setup bus to read data */ 295 temp = readb(&i2c_regs->i2cr); 296 temp &= ~(I2CR_MTX | I2CR_TX_NO_AK); 297 if (len == 1) 298 temp |= I2CR_TX_NO_AK; 299 writeb(temp, &i2c_regs->i2cr); 300 writeb(0, &i2c_regs->i2sr); 301 readb(&i2c_regs->i2dr); /* dummy read to clear ICF */ 302 303 /* read data */ 304 for (i = 0; i < len; i++) { 305 ret = wait_for_sr_state(i2c_regs, ST_IIF); 306 if (ret < 0) { 307 i2c_imx_stop(); 308 return ret; 309 } 310 311 /* 312 * It must generate STOP before read I2DR to prevent 313 * controller from generating another clock cycle 314 */ 315 if (i == (len - 1)) { 316 i2c_imx_stop(); 317 } else if (i == (len - 2)) { 318 temp = readb(&i2c_regs->i2cr); 319 temp |= I2CR_TX_NO_AK; 320 writeb(temp, &i2c_regs->i2cr); 321 } 322 writeb(0, &i2c_regs->i2sr); 323 buf[i] = readb(&i2c_regs->i2dr); 324 } 325 326 i2c_imx_stop(); 327 328 return 0; 329 } 330 331 /* 332 * Write data to I2C device 333 */ 334 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len) 335 { 336 struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; 337 int ret; 338 int i; 339 340 ret = i2c_init_transfer(i2c_regs, chip, addr, alen); 341 if (ret < 0) 342 return ret; 343 344 for (i = 0; i < len; i++) { 345 ret = tx_byte(i2c_regs, buf[i]); 346 if (ret < 0) 347 break; 348 } 349 350 i2c_imx_stop(); 351 352 return ret; 353 } 354 355 /* 356 * Test if a chip at a given address responds (probe the chip) 357 */ 358 int i2c_probe(uchar chip) 359 { 360 return i2c_write(chip, 0, 0, NULL, 0); 361 } 362