drivers/i2c/mxc_i2c.c

   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 #elif defined (CONFIG_SYS_I2C_MX31_PORT2)
  53 #define I2C_BASE        0x43f98000
  54 #elif defined (CONFIG_SYS_I2C_MX31_PORT3)
  55 #define I2C_BASE        0x43f84000
  56 #else
  57 #error "define CONFIG_SYS_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 */