drivers/i2c/ihs_i2c.c

   1 /*
   2  * (C) Copyright 2013
   3  * Dirk Eibach,  Guntermann & Drunck GmbH, eibach@gdsys.de
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <i2c.h>
  10 #include <gdsys_fpga.h>
  11
  12 DECLARE_GLOBAL_DATA_PTR;
  13
  14 enum {
  15         I2CINT_ERROR_EV = 1 << 13,
  16         I2CINT_TRANSMIT_EV = 1 << 14,
  17         I2CINT_RECEIVE_EV = 1 << 15,
  18 };
  19
  20 enum {
  21         I2CMB_WRITE = 1 << 10,
  22         I2CMB_2BYTE = 1 << 11,
  23         I2CMB_HOLD_BUS = 1 << 13,
  24         I2CMB_NATIVE = 2 << 14,
  25 };
  26
  27 static int wait_for_int(bool read)
  28 {
  29         u16 val;
  30         unsigned int ctr = 0;
  31
  32         FPGA_GET_REG(I2C_ADAP_HWNR, i2c.interrupt_status, &val);
  33         while (!(val & (I2CINT_ERROR_EV
  34                | (read ? I2CINT_RECEIVE_EV : I2CINT_TRANSMIT_EV)))) {
  35                 udelay(10);
  36                 if (ctr++ > 5000) {
  37                         return 1;
  38                 }
  39                 FPGA_GET_REG(I2C_ADAP_HWNR, i2c.interrupt_status, &val);
  40         }
  41
  42         return (val & I2CINT_ERROR_EV) ? 1 : 0;
  43 }
  44
  45 static int ihs_i2c_transfer(uchar chip, uchar *buffer, int len, bool read,
  46                             bool is_last)
  47 {
  48         u16 val;
  49
  50         FPGA_SET_REG(I2C_ADAP_HWNR, i2c.interrupt_status, I2CINT_ERROR_EV
  51                      | I2CINT_RECEIVE_EV | I2CINT_TRANSMIT_EV);
  52         FPGA_GET_REG(I2C_ADAP_HWNR, i2c.interrupt_status, &val);
  53
  54         if (!read && len) {
  55                 val = buffer[0];
  56
  57                 if (len > 1)
  58                         val |= buffer[1] << 8;
  59                 FPGA_SET_REG(I2C_ADAP_HWNR, i2c.write_mailbox_ext, val);
  60         }
  61
  62         FPGA_SET_REG(I2C_ADAP_HWNR, i2c.write_mailbox,
  63                      I2CMB_NATIVE
  64                      | (read ? 0 : I2CMB_WRITE)
  65                      | (chip << 1)
  66                      | ((len > 1) ? I2CMB_2BYTE : 0)
  67                      | (is_last ? 0 : I2CMB_HOLD_BUS));
  68
  69         if (wait_for_int(read))
  70                 return 1;
  71
  72         if (read) {
  73                 FPGA_GET_REG(I2C_ADAP_HWNR, i2c.read_mailbox_ext, &val);
  74                 buffer[0] = val & 0xff;
  75                 if (len > 1)
  76                         buffer[1] = val >> 8;
  77         }
  78
  79         return 0;
  80 }
  81
  82 static int ihs_i2c_address(uchar chip, uint addr, int alen, bool hold_bus)
  83 {
  84         int shift = (alen-1) * 8;
  85
  86         while (alen) {
  87                 int transfer = min(alen, 2);
  88                 uchar buf[2];
  89                 bool is_last = alen <= transfer;
  90
  91                 buf[0] = addr >> shift;
  92                 if (alen > 1)
  93                         buf[1] = addr >> (shift - 8);
  94
  95                 if (ihs_i2c_transfer(chip, buf, transfer, false,
  96                                      hold_bus ? false : is_last))
  97                         return 1;
  98
  99                 shift -= 16;
 100                 alen -= transfer;
 101         }
 102
 103         return 0;
 104 }
 105
 106 static int ihs_i2c_access(struct i2c_adapter *adap, uchar chip, uint addr,
 107                           int alen, uchar *buffer, int len, bool read)
 108 {
 109         if (len <= 0)
 110                 return 1;
 111
 112         if (ihs_i2c_address(chip, addr, alen, !read))
 113                 return 1;
 114
 115         while (len) {
 116                 int transfer = min(len, 2);
 117
 118                 if (ihs_i2c_transfer(chip, buffer, transfer, read,
 119                                      len <= transfer))
 120                         return 1;
 121
 122                 buffer += transfer;
 123                 addr += transfer;
 124                 len -= transfer;
 125         }
 126
 127         return 0;
 128 }
 129
 130
 131 static void ihs_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
 132 {
 133 #ifdef CONFIG_SYS_I2C_INIT_BOARD
 134         /*
 135          * Call board specific i2c bus reset routine before accessing the
 136          * environment, which might be in a chip on that bus. For details
 137          * about this problem see doc/I2C_Edge_Conditions.
 138          */
 139         i2c_init_board();
 140 #endif
 141 }
 142
 143 static int ihs_i2c_probe(struct i2c_adapter *adap, uchar chip)
 144 {
 145         uchar buffer[2];
 146
 147         if (ihs_i2c_transfer(chip, buffer, 0, true, true))
 148                 return 1;
 149
 150         return 0;
 151 }
 152
 153 static int ihs_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
 154                         int alen, uchar *buffer, int len)
 155 {
 156         return ihs_i2c_access(adap, chip, addr, alen, buffer, len, true);
 157 }
 158
 159 static int ihs_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
 160                          int alen, uchar *buffer, int len)
 161 {
 162         return ihs_i2c_access(adap, chip, addr, alen, buffer, len, false);
 163 }
 164
 165 static unsigned int ihs_i2c_set_bus_speed(struct i2c_adapter *adap,
 166                                              unsigned int speed)
 167 {
 168         if (speed != adap->speed)
 169                 return 1;
 170         return speed;
 171 }
 172
 173 /*
 174  * Register IHS i2c adapters
 175  */
 176 #ifdef CONFIG_SYS_I2C_IHS_CH0
 177 U_BOOT_I2C_ADAP_COMPLETE(ihs0, ihs_i2c_init, ihs_i2c_probe,
 178                          ihs_i2c_read, ihs_i2c_write,
 179                          ihs_i2c_set_bus_speed,
 180                          CONFIG_SYS_I2C_IHS_SPEED_0,
 181                          CONFIG_SYS_I2C_IHS_SLAVE_0, 0)
 182 #endif
 183 #ifdef CONFIG_SYS_I2C_IHS_CH1
 184 U_BOOT_I2C_ADAP_COMPLETE(ihs1, ihs_i2c_init, ihs_i2c_probe,
 185                          ihs_i2c_read, ihs_i2c_write,
 186                          ihs_i2c_set_bus_speed,
 187                          CONFIG_SYS_I2C_IHS_SPEED_1,
 188                          CONFIG_SYS_I2C_IHS_SLAVE_1, 1)
 189 #endif
 190 #ifdef CONFIG_SYS_I2C_IHS_CH2
 191 U_BOOT_I2C_ADAP_COMPLETE(ihs2, ihs_i2c_init, ihs_i2c_probe,
 192                          ihs_i2c_read, ihs_i2c_write,
 193                          ihs_i2c_set_bus_speed,
 194                          CONFIG_SYS_I2C_IHS_SPEED_2,
 195                          CONFIG_SYS_I2C_IHS_SLAVE_2, 2)
 196 #endif
 197 #ifdef CONFIG_SYS_I2C_IHS_CH3
 198 U_BOOT_I2C_ADAP_COMPLETE(ihs3, ihs_i2c_init, ihs_i2c_probe,
 199                          ihs_i2c_read, ihs_i2c_write,
 200                          ihs_i2c_set_bus_speed,
 201                          CONFIG_SYS_I2C_IHS_SPEED_3,
 202                          CONFIG_SYS_I2C_IHS_SLAVE_3, 3)
 203 #endif