drivers/gpu/drm/radeon/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/radeon_drm.h>
  27 #include "radeon.h"
  28 #include "atom.h"
  29
  30 #define TARGET_HW_I2C_CLOCK 50
  31
  32 /* these are a limitation of ProcessI2cChannelTransaction not the hw */
  33 #define ATOM_MAX_HW_I2C_WRITE 3
  34 #define ATOM_MAX_HW_I2C_READ  255
  35
  36 static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
  37                                  u8 slave_addr, u8 flags,
  38                                  u8 *buf, int num)
  39 {
  40         struct drm_device *dev = chan->dev;
  41         struct radeon_device *rdev = dev->dev_private;
  42         PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
  43         int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
  44         unsigned char *base;
  45         u16 out = cpu_to_le16(0);
  46         int r = 0;
  47
  48         memset(&args, 0, sizeof(args));
  49
  50         mutex_lock(&chan->mutex);
  51         mutex_lock(&rdev->mode_info.atom_context->scratch_mutex);
  52
  53         base = (unsigned char *)rdev->mode_info.atom_context->scratch;
  54
  55         if (flags & HW_I2C_WRITE) {
  56                 if (num > ATOM_MAX_HW_I2C_WRITE) {
  57                         DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
  58                         r = -EINVAL;
  59                         goto done;
  60                 }
  61                 if (buf == NULL)
  62                         args.ucRegIndex = 0;
  63                 else
  64                         args.ucRegIndex = buf[0];
  65                 if (num)
  66                         num--;
  67                 if (num)
  68                         memcpy(&out, &buf[1], num);
  69                 args.lpI2CDataOut = cpu_to_le16(out);
  70         } else {
  71                 args.ucRegIndex = 0;
  72                 args.lpI2CDataOut = 0;
  73         }
  74
  75         args.ucFlag = flags;
  76         args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
  77         args.ucTransBytes = num;
  78         args.ucSlaveAddr = slave_addr << 1;
  79         args.ucLineNumber = chan->rec.i2c_id;
  80
  81         atom_execute_table_scratch_unlocked(rdev->mode_info.atom_context, index, (uint32_t *)&args);
  82
  83         /* error */
  84         if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
  85                 DRM_DEBUG_KMS("hw_i2c error\n");
  86                 r = -EIO;
  87                 goto done;
  88         }
  89
  90         if (!(flags & HW_I2C_WRITE))
  91                 radeon_atom_copy_swap(buf, base, num, false);
  92
  93 done:
  94         mutex_unlock(&rdev->mode_info.atom_context->scratch_mutex);
  95         mutex_unlock(&chan->mutex);
  96
  97         return r;
  98 }
  99
 100 int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
 101                             struct i2c_msg *msgs, int num)
 102 {
 103         struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
 104         struct i2c_msg *p;
 105         int i, remaining, current_count, buffer_offset, max_bytes, ret;
 106         u8 flags;
 107
 108         /* check for bus probe */
 109         p = &msgs[0];
 110         if ((num == 1) && (p->len == 0)) {
 111                 ret = radeon_process_i2c_ch(i2c,
 112                                             p->addr, HW_I2C_WRITE,
 113                                             NULL, 0);
 114                 if (ret)
 115                         return ret;
 116                 else
 117                         return num;
 118         }
 119
 120         for (i = 0; i < num; i++) {
 121                 p = &msgs[i];
 122                 remaining = p->len;
 123                 buffer_offset = 0;
 124                 /* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
 125                 if (p->flags & I2C_M_RD) {
 126                         max_bytes = ATOM_MAX_HW_I2C_READ;
 127                         flags = HW_I2C_READ;
 128                 } else {
 129                         max_bytes = ATOM_MAX_HW_I2C_WRITE;
 130                         flags = HW_I2C_WRITE;
 131                 }
 132                 while (remaining) {
 133                         if (remaining > max_bytes)
 134                                 current_count = max_bytes;
 135                         else
 136                                 current_count = remaining;
 137                         ret = radeon_process_i2c_ch(i2c,
 138                                                     p->addr, flags,
 139                                                     &p->buf[buffer_offset], current_count);
 140                         if (ret)
 141                                 return ret;
 142                         remaining -= current_count;
 143                         buffer_offset += current_count;
 144                 }
 145         }
 146
 147         return num;
 148 }
 149
 150 u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
 151 {
 152         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 153 }
 154