i2c.c 8.18 KB
Newer Older
1
/*
2
 * (C) Copyright 2003 - 2009
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 *
 * Based on the MPC5xxx code.
 */

#include <common.h>
27
#include <asm/io.h>
28 29 30 31 32 33 34 35

DECLARE_GLOBAL_DATA_PTR;

#ifdef CONFIG_HARD_I2C

#include <i2c.h>

/* by default set I2C bus 0 active */
36
static unsigned int bus_num __attribute__ ((section (".data"))) = 0;
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56

#define I2C_TIMEOUT	100
#define I2C_RETRIES	3

struct mpc512x_i2c_tap {
	int scl2tap;
	int tap2tap;
};

static int  mpc_reg_in(volatile u32 *reg);
static void mpc_reg_out(volatile u32 *reg, int val, int mask);
static int  wait_for_bb(void);
static int  wait_for_pin(int *status);
static int  do_address(uchar chip, char rdwr_flag);
static int  send_bytes(uchar chip, char *buf, int len);
static int  receive_bytes(uchar chip, char *buf, int len);
static int  mpc_get_fdr(int);

static int mpc_reg_in (volatile u32 *reg)
{
57 58
	int ret = in_be32(reg) >> 24;

59 60 61 62 63 64
	return ret;
}

static void mpc_reg_out (volatile u32 *reg, int val, int mask)
{
	if (!mask) {
65
		out_be32(reg, val << 24);
66
	} else {
67
		clrsetbits_be32(reg, mask << 24, (val & mask) << 24);
68 69 70 71 72
	}
}

static int wait_for_bb (void)
{
73 74
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96
	int timeout = I2C_TIMEOUT;
	int status;

	status = mpc_reg_in (&regs->msr);

	while (timeout-- && (status & I2C_BB)) {
		volatile int temp;
		mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);
		temp = mpc_reg_in (&regs->mdr);
		mpc_reg_out (&regs->mcr, 0, I2C_STA);
		mpc_reg_out (&regs->mcr, 0, 0);
		mpc_reg_out (&regs->mcr, I2C_EN, 0);

		udelay (1000);
		status = mpc_reg_in (&regs->msr);
	}

	return (status & I2C_BB);
}

static int wait_for_pin (int *status)
{
97 98
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118
	int timeout = I2C_TIMEOUT;

	*status = mpc_reg_in (&regs->msr);

	while (timeout-- && !(*status & I2C_IF)) {
		udelay (1000);
		*status = mpc_reg_in (&regs->msr);
	}

	if (!(*status & I2C_IF)) {
		return -1;
	}

	mpc_reg_out (&regs->msr, 0, I2C_IF);

	return 0;
}

static int do_address (uchar chip, char rdwr_flag)
{
119 120
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144
	int status;

	chip <<= 1;

	if (rdwr_flag) {
		chip |= 1;
	}

	mpc_reg_out (&regs->mcr, I2C_TX, I2C_TX);
	mpc_reg_out (&regs->mdr, chip, 0);

	if (wait_for_pin (&status)) {
		return -2;
	}

	if (status & I2C_RXAK) {
		return -3;
	}

	return 0;
}

static int send_bytes (uchar chip, char *buf, int len)
{
145 146
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168
	int wrcount;
	int status;

	for (wrcount = 0; wrcount < len; ++wrcount) {

		mpc_reg_out (&regs->mdr, buf[wrcount], 0);

		if (wait_for_pin (&status)) {
			break;
		}

		if (status & I2C_RXAK) {
			break;
		}

	}

	return !(wrcount == len);
}

static int receive_bytes (uchar chip, char *buf, int len)
{
169 170
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207
	int dummy   = 1;
	int rdcount = 0;
	int status;
	int i;

	mpc_reg_out (&regs->mcr, 0, I2C_TX);

	for (i = 0; i < len; ++i) {
		buf[rdcount] = mpc_reg_in (&regs->mdr);

		if (dummy) {
			dummy = 0;
		} else {
			rdcount++;
		}

		if (wait_for_pin (&status)) {
			return -4;
		}
	}

	mpc_reg_out (&regs->mcr, I2C_TXAK, I2C_TXAK);
	buf[rdcount++] = mpc_reg_in (&regs->mdr);

	if (wait_for_pin (&status)) {
		return -5;
	}

	mpc_reg_out (&regs->mcr, 0, I2C_TXAK);

	return 0;
}

/**************** I2C API ****************/

void i2c_init (int speed, int saddr)
{
208
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
209
	int i;
210 211 212 213

	for (i = 0; i < I2C_BUS_CNT; i++){
		volatile i2c512x_dev_t *regs = &im->i2c.dev[i];

214 215 216 217 218 219 220 221 222 223 224 225
		mpc_reg_out (&regs->mcr, 0, 0);

		/* Set clock */
		mpc_reg_out (&regs->mfdr, mpc_get_fdr (speed), 0);
		mpc_reg_out (&regs->madr, saddr << 1, 0);

		/* Enable module */
		mpc_reg_out (&regs->mcr, I2C_EN, I2C_INIT_MASK);
		mpc_reg_out (&regs->msr, 0, I2C_IF);
	}

	/* Disable interrupts */
226 227
	out_be32(&im->i2c.icr, 0);

228
	/* Turn off filters */
229
	out_be32(&im->i2c.mifr, 0);
230 231 232 233 234 235 236 237 238
}

static int mpc_get_fdr (int speed)
{
	static int fdr = -1;

	if (fdr == -1) {
		ulong best_speed = 0;
		ulong divider;
239
		ulong ips, scl;
240 241 242 243 244 245 246 247 248 249 250 251 252 253
		ulong bestmatch = 0xffffffffUL;
		int best_i = 0, best_j = 0, i, j;
		int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8};
		struct mpc512x_i2c_tap scltap[] = {
			{4, 1},
			{4, 2},
			{6, 4},
			{6, 8},
			{14, 16},
			{30, 32},
			{62, 64},
			{126, 128}
		};

254
		ips = gd->ips_clk;
255 256 257 258 259
		for (i = 7; i >= 0; i--) {
			for (j = 7; j >= 0; j--) {
				scl = 2 * (scltap[j].scl2tap +
					   (SCL_Tap[i] - 1) * scltap[j].tap2tap
					   + 2);
260 261 262
				if (ips <= speed*scl) {
					if ((speed*scl - ips) < bestmatch) {
						bestmatch = speed*scl - ips;
263 264
						best_i = i;
						best_j = j;
265
						best_speed = ips/scl;
266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283
					}
				}
			}
		}
		divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
		if (gd->flags & GD_FLG_RELOC) {
			fdr = divider;
		} else {
			debug("%ld kHz, \n", best_speed / 1000);
			return divider;
		}
	}

	return fdr;
}

int i2c_probe (uchar chip)
{
284 285
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305
	int i;

	for (i = 0; i < I2C_RETRIES; i++) {
		mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);

		if (! do_address (chip, 0)) {
			mpc_reg_out (&regs->mcr, 0, I2C_STA);
			udelay (500);
			break;
		}

		mpc_reg_out (&regs->mcr, 0, I2C_STA);
		udelay (500);
	}

	return (i == I2C_RETRIES);
}

int i2c_read (uchar chip, uint addr, int alen, uchar *buf, int len)
{
306 307
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350
	char xaddr[4];
	int ret = -1;

	xaddr[0] = (addr >> 24) & 0xFF;
	xaddr[1] = (addr >> 16) & 0xFF;
	xaddr[2] = (addr >>  8) & 0xFF;
	xaddr[3] =  addr	& 0xFF;

	if (wait_for_bb ()) {
		printf ("i2c_read: bus is busy\n");
		goto Done;
	}

	mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);
	if (do_address (chip, 0)) {
		printf ("i2c_read: failed to address chip\n");
		goto Done;
	}

	if (send_bytes (chip, &xaddr[4-alen], alen)) {
		printf ("i2c_read: send_bytes failed\n");
		goto Done;
	}

	mpc_reg_out (&regs->mcr, I2C_RSTA, I2C_RSTA);
	if (do_address (chip, 1)) {
		printf ("i2c_read: failed to address chip\n");
		goto Done;
	}

	if (receive_bytes (chip, (char *)buf, len)) {
		printf ("i2c_read: receive_bytes failed\n");
		goto Done;
	}

	ret = 0;
Done:
	mpc_reg_out (&regs->mcr, 0, I2C_STA);
	return ret;
}

int i2c_write (uchar chip, uint addr, int alen, uchar *buf, int len)
{
351 352
	volatile immap_t *im = (immap_t *) CONFIG_SYS_IMMR;
	volatile i2c512x_dev_t *regs = &im->i2c.dev[bus_num];
353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403
	char xaddr[4];
	int ret = -1;

	xaddr[0] = (addr >> 24) & 0xFF;
	xaddr[1] = (addr >> 16) & 0xFF;
	xaddr[2] = (addr >>  8) & 0xFF;
	xaddr[3] =  addr	& 0xFF;

	if (wait_for_bb ()) {
		printf ("i2c_write: bus is busy\n");
		goto Done;
	}

	mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);
	if (do_address (chip, 0)) {
		printf ("i2c_write: failed to address chip\n");
		goto Done;
	}

	if (send_bytes (chip, &xaddr[4-alen], alen)) {
		printf ("i2c_write: send_bytes failed\n");
		goto Done;
	}

	if (send_bytes (chip, (char *)buf, len)) {
		printf ("i2c_write: send_bytes failed\n");
		goto Done;
	}

	ret = 0;
Done:
	mpc_reg_out (&regs->mcr, 0, I2C_STA);
	return ret;
}

int i2c_set_bus_num (unsigned int bus)
{
	if (bus >= I2C_BUS_CNT) {
		return -1;
	}
	bus_num = bus;

	return 0;
}

unsigned int i2c_get_bus_num (void)
{
	return bus_num;
}

#endif	/* CONFIG_HARD_I2C */