drivers/gpu/drm/amd/amdgpu/atombios_i2c.c

   1 /*
   2  * Copyright 2011 Advanced Micro Devices, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * Authors: Alex Deucher
  23  *
  24  */
  25
  26 #include <drm/amdgpu_drm.h>
  27 #include "amdgpu.h"
  28 #include "atom.h"
  29 #include "amdgpu_atombios.h"
  30 #include "atombios_i2c.h"
  31
  32 #define TARGET_HW_I2C_CLOCK 50
  33
  34 /* these are a limitation of ProcessI2cChannelTransaction not the hw */
  35 #define ATOM_MAX_HW_I2C_WRITE 3
  36 #define ATOM_MAX_HW_I2C_READ  255
  37
  38 static int amdgpu_atombios_i2c_process_i2c_ch(struct amdgpu_i2c_chan *chan,
  39                                        u8 slave_addr, u8 flags,
  40                                        u8 *buf, u8 num)
  41 {
  42         struct drm_device *dev = chan->dev;
  43         struct amdgpu_device *adev = drm_to_adev(dev);
  44         PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
  45         int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
  46         unsigned char *base;
  47         u16 out = cpu_to_le16(0);
  48         int r = 0;
  49
  50         memset(&args, 0, sizeof(args));
  51
  52         mutex_lock(&chan->mutex);
  53
  54         base = (unsigned char *)adev->mode_info.atom_context->scratch;
  55
  56         if (flags & HW_I2C_WRITE) {
  57                 if (num > ATOM_MAX_HW_I2C_WRITE) {
  58                         DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
  59                         r = -EINVAL;
  60                         goto done;
  61                 }
  62                 if (buf == NULL)
  63                         args.ucRegIndex = 0;
  64                 else
  65                         args.ucRegIndex = buf[0];
  66                 if (num)
  67                         num--;
  68                 if (num) {
  69                         if (buf) {
  70                                 memcpy(&out, &buf[1], num);
  71                         } else {
  72                                 DRM_ERROR("hw i2c: missing buf with num > 1\n");
  73                                 r = -EINVAL;
  74                                 goto done;
  75                         }
  76                 }
  77                 args.lpI2CDataOut = cpu_to_le16(out);
  78         } else {
  79                 args.ucRegIndex = 0;
  80                 args.lpI2CDataOut = 0;
  81         }
  82
  83         args.ucFlag = flags;
  84         args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
  85         args.ucTransBytes = num;
  86         args.ucSlaveAddr = slave_addr << 1;
  87         args.ucLineNumber = chan->rec.i2c_id;
  88
  89         amdgpu_atom_execute_table(adev->mode_info.atom_context, index, (uint32_t *)&args, sizeof(args));
  90
  91         /* error */
  92         if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
  93                 DRM_DEBUG_KMS("hw_i2c error\n");
  94                 r = -EIO;
  95                 goto done;
  96         }
  97
  98         if (!(flags & HW_I2C_WRITE))
  99                 amdgpu_atombios_copy_swap(buf, base, num, false);
 100
 101 done:
 102         mutex_unlock(&chan->mutex);
 103
 104         return r;
 105 }
 106
 107 int amdgpu_atombios_i2c_xfer(struct i2c_adapter *i2c_adap,
 108                       struct i2c_msg *msgs, int num)
 109 {
 110         struct amdgpu_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
 111         struct i2c_msg *p;
 112         int i, remaining, current_count, buffer_offset, max_bytes, ret;
 113         u8 flags;
 114
 115         /* check for bus probe */
 116         p = &msgs[0];
 117         if ((num == 1) && (p->len == 0)) {
 118                 ret = amdgpu_atombios_i2c_process_i2c_ch(i2c,
 119                                                   p->addr, HW_I2C_WRITE,
 120                                                   NULL, 0);
 121                 if (ret)
 122                         return ret;
 123                 else
 124                         return num;
 125         }
 126
 127         for (i = 0; i < num; i++) {
 128                 p = &msgs[i];
 129                 remaining = p->len;
 130                 buffer_offset = 0;
 131                 /* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
 132                 if (p->flags & I2C_M_RD) {
 133                         max_bytes = ATOM_MAX_HW_I2C_READ;
 134                         flags = HW_I2C_READ;
 135                 } else {
 136                         max_bytes = ATOM_MAX_HW_I2C_WRITE;
 137                         flags = HW_I2C_WRITE;
 138                 }
 139                 while (remaining) {
 140                         if (remaining > max_bytes)
 141                                 current_count = max_bytes;
 142                         else
 143                                 current_count = remaining;
 144                         ret = amdgpu_atombios_i2c_process_i2c_ch(i2c,
 145                                                           p->addr, flags,
 146                                                           &p->buf[buffer_offset], current_count);
 147                         if (ret)
 148                                 return ret;
 149                         remaining -= current_count;
 150                         buffer_offset += current_count;
 151                 }
 152         }
 153
 154         return num;
 155 }
 156
 157 u32 amdgpu_atombios_i2c_func(struct i2c_adapter *adap)
 158 {
 159         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 160 }
 161
 162 void amdgpu_atombios_i2c_channel_trans(struct amdgpu_device *adev, u8 slave_addr, u8 line_number, u8 offset, u8 data)
 163 {
 164         PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
 165         int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
 166
 167         args.ucRegIndex = offset;
 168         args.lpI2CDataOut = data;
 169         args.ucFlag = 1;
 170         args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
 171         args.ucTransBytes = 1;
 172         args.ucSlaveAddr = slave_addr;
 173         args.ucLineNumber = line_number;
 174
 175         amdgpu_atom_execute_table(adev->mode_info.atom_context, index, (uint32_t *)&args, sizeof(args));
 176 }