drivers/i2c/mxs_i2c.c

   1 /*
   2  * Freescale i.MX28 I2C Driver
   3  *
   4  * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
   5  * on behalf of DENX Software Engineering GmbH
   6  *
   7  * Partly based on Linux kernel i2c-mxs.c driver:
   8  * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
   9  *
  10  * Which was based on a (non-working) driver which was:
  11  * Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  26  *
  27  */
  28
  29 #include <common.h>
  30 #include <malloc.h>
  31 #include <asm/errno.h>
  32 #include <asm/io.h>
  33 #include <asm/arch/clock.h>
  34 #include <asm/arch/imx-regs.h>
  35 #include <asm/arch/sys_proto.h>
  36
  37 #define MXS_I2C_MAX_TIMEOUT     1000000
  38
  39 void mxs_i2c_reset(void)
  40 {
  41         struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE;
  42         int ret;
  43
  44         ret = mx28_reset_block(&i2c_regs->hw_i2c_ctrl0_reg);
  45         if (ret) {
  46                 debug("MXS I2C: Block reset timeout\n");
  47                 return;
  48         }
  49
  50         writel(I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | I2C_CTRL1_NO_SLAVE_ACK_IRQ |
  51                 I2C_CTRL1_EARLY_TERM_IRQ | I2C_CTRL1_MASTER_LOSS_IRQ |
  52                 I2C_CTRL1_SLAVE_STOP_IRQ | I2C_CTRL1_SLAVE_IRQ,
  53                 &i2c_regs->hw_i2c_ctrl1_clr);
  54
  55         writel(I2C_QUEUECTRL_PIO_QUEUE_MODE, &i2c_regs->hw_i2c_queuectrl_set);
  56 }
  57
  58 void mxs_i2c_setup_read(uint8_t chip, int len)
  59 {
  60         struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE;
  61
  62         writel(I2C_QUEUECMD_RETAIN_CLOCK | I2C_QUEUECMD_PRE_SEND_START |
  63                 I2C_QUEUECMD_MASTER_MODE | I2C_QUEUECMD_DIRECTION |
  64                 (1 << I2C_QUEUECMD_XFER_COUNT_OFFSET),
  65                 &i2c_regs->hw_i2c_queuecmd);
  66
  67         writel((chip << 1) | 1, &i2c_regs->hw_i2c_data);
  68
  69         writel(I2C_QUEUECMD_SEND_NAK_ON_LAST | I2C_QUEUECMD_MASTER_MODE |
  70                 (len << I2C_QUEUECMD_XFER_COUNT_OFFSET) |
  71                 I2C_QUEUECMD_POST_SEND_STOP, &i2c_regs->hw_i2c_queuecmd);
  72
  73         writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set);
  74 }
  75
  76 void mxs_i2c_write(uchar chip, uint addr, int alen,
  77                         uchar *buf, int blen, int stop)
  78 {
  79         struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE;
  80         uint32_t data;
  81         int i, remain, off;
  82
  83         if ((alen > 4) || (alen == 0)) {
  84                 debug("MXS I2C: Invalid address length\n");
  85                 return;
  86         }
  87
  88         if (stop)
  89                 stop = I2C_QUEUECMD_POST_SEND_STOP;
  90
  91         writel(I2C_QUEUECMD_PRE_SEND_START |
  92                 I2C_QUEUECMD_MASTER_MODE | I2C_QUEUECMD_DIRECTION |
  93                 ((blen + alen + 1) << I2C_QUEUECMD_XFER_COUNT_OFFSET) | stop,
  94                 &i2c_regs->hw_i2c_queuecmd);
  95
  96         data = (chip << 1) << 24;
  97
  98         for (i = 0; i < alen; i++) {
  99                 data >>= 8;
 100                 data |= ((char *)&addr)[alen - i - 1] << 24;
 101                 if ((i & 3) == 2)
 102                         writel(data, &i2c_regs->hw_i2c_data);
 103         }
 104
 105         off = i;
 106         for (; i < off + blen; i++) {
 107                 data >>= 8;
 108                 data |= buf[i - off] << 24;
 109                 if ((i & 3) == 2)
 110                         writel(data, &i2c_regs->hw_i2c_data);
 111         }
 112
 113         remain = 24 - ((i & 3) * 8);
 114         if (remain)
 115                 writel(data >> remain, &i2c_regs->hw_i2c_data);
 116
 117         writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set);
 118 }
 119
 120 int mxs_i2c_wait_for_ack(void)
 121 {
 122         struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE;
 123         uint32_t tmp;
 124         int timeout = MXS_I2C_MAX_TIMEOUT;
 125
 126         for (;;) {
 127                 tmp = readl(&i2c_regs->hw_i2c_ctrl1);
 128                 if (tmp & I2C_CTRL1_NO_SLAVE_ACK_IRQ) {
 129                         debug("MXS I2C: No slave ACK\n");
 130                         goto err;
 131                 }
 132
 133                 if (tmp & (
 134                         I2C_CTRL1_EARLY_TERM_IRQ | I2C_CTRL1_MASTER_LOSS_IRQ |
 135                         I2C_CTRL1_SLAVE_STOP_IRQ | I2C_CTRL1_SLAVE_IRQ)) {
 136                         debug("MXS I2C: Error (CTRL1 = %08x)\n", tmp);
 137                         goto err;
 138                 }
 139
 140                 if (tmp & I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ)
 141                         break;
 142
 143                 if (!timeout--) {
 144                         debug("MXS I2C: Operation timed out\n");
 145                         goto err;
 146                 }
 147
 148                 udelay(1);
 149         }
 150
 151         return 0;
 152
 153 err:
 154         mxs_i2c_reset();
 155         return 1;
 156 }
 157
 158 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 159 {
 160         struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE;
 161         uint32_t tmp = 0;
 162         int ret;
 163         int i;
 164
 165         mxs_i2c_write(chip, addr, alen, NULL, 0, 0);
 166         ret = mxs_i2c_wait_for_ack();
 167         if (ret) {
 168                 debug("MXS I2C: Failed writing address\n");
 169                 return ret;
 170         }
 171
 172         mxs_i2c_setup_read(chip, len);
 173         ret = mxs_i2c_wait_for_ack();
 174         if (ret) {
 175                 debug("MXS I2C: Failed reading address\n");
 176                 return ret;
 177         }
 178
 179         for (i = 0; i < len; i++) {
 180                 if (!(i & 3)) {
 181                         while (readl(&i2c_regs->hw_i2c_queuestat) &
 182                                 I2C_QUEUESTAT_RD_QUEUE_EMPTY)
 183                                 ;
 184                         tmp = readl(&i2c_regs->hw_i2c_queuedata);
 185                 }
 186                 buffer[i] = tmp & 0xff;
 187                 tmp >>= 8;
 188         }
 189
 190         return 0;
 191 }
 192
 193 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 194 {
 195         int ret;
 196         mxs_i2c_write(chip, addr, alen, buffer, len, 1);
 197         ret = mxs_i2c_wait_for_ack();
 198         if (ret)
 199                 debug("MXS I2C: Failed writing address\n");
 200
 201         return ret;
 202 }
 203
 204 int i2c_probe(uchar chip)
 205 {
 206         int ret;
 207         mxs_i2c_write(chip, 0, 1, NULL, 0, 1);
 208         ret = mxs_i2c_wait_for_ack();
 209         mxs_i2c_reset();
 210         return ret;
 211 }
 212
 213 void i2c_init(int speed, int slaveadd)
 214 {
 215         struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE;
 216
 217         mxs_i2c_reset();
 218
 219         switch (speed) {
 220         case 100000:
 221                 writel((0x0078 << I2C_TIMING0_HIGH_COUNT_OFFSET) |
 222                         (0x0030 << I2C_TIMING0_RCV_COUNT_OFFSET),
 223                         &i2c_regs->hw_i2c_timing0);
 224                 writel((0x0080 << I2C_TIMING1_LOW_COUNT_OFFSET) |
 225                         (0x0030 << I2C_TIMING1_XMIT_COUNT_OFFSET),
 226                         &i2c_regs->hw_i2c_timing1);
 227                 break;
 228         case 400000:
 229                 writel((0x000f << I2C_TIMING0_HIGH_COUNT_OFFSET) |
 230                         (0x0007 << I2C_TIMING0_RCV_COUNT_OFFSET),
 231                         &i2c_regs->hw_i2c_timing0);
 232                 writel((0x001f << I2C_TIMING1_LOW_COUNT_OFFSET) |
 233                         (0x000f << I2C_TIMING1_XMIT_COUNT_OFFSET),
 234                         &i2c_regs->hw_i2c_timing1);
 235                 break;
 236         default:
 237                 printf("MXS I2C: Invalid speed selected (%d Hz)\n", speed);
 238                 return;
 239         }
 240
 241         writel((0x0015 << I2C_TIMING2_BUS_FREE_OFFSET) |
 242                 (0x000d << I2C_TIMING2_LEADIN_COUNT_OFFSET),
 243                 &i2c_regs->hw_i2c_timing2);
 244
 245         return;
 246 }