drm/radeon/atombios_i2c.c

0001 /*
0002  * Copyright 2011 Advanced Micro Devices, Inc.
0003  *
0004  * Permission is hereby granted, free of charge, to any person obtaining a
0005  * copy of this software and associated documentation files (the "Software"),
0006  * to deal in the Software without restriction, including without limitation
0007  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
0008  * and/or sell copies of the Software, and to permit persons to whom the
0009  * Software is furnished to do so, subject to the following conditions:
0010  *
0011  * The above copyright notice and this permission notice shall be included in
0012  * all copies or substantial portions of the Software.
0013  *
0014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
0017  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
0018  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
0019  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
0020  * OTHER DEALINGS IN THE SOFTWARE.
0021  *
0022  * Authors: Alex Deucher
0023  *
0024  */
0025
0026 #include <drm/radeon_drm.h>
0027 #include "radeon.h"
0028 #include "atom.h"
0029
0030 #define TARGET_HW_I2C_CLOCK 50
0031
0032 /* these are a limitation of ProcessI2cChannelTransaction not the hw */
0033 #define ATOM_MAX_HW_I2C_WRITE 3
0034 #define ATOM_MAX_HW_I2C_READ  255
0035
0036 static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
0037                  u8 slave_addr, u8 flags,
0038                  u8 *buf, int num)
0039 {
0040     struct drm_device *dev = chan->dev;
0041     struct radeon_device *rdev = dev->dev_private;
0042     PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
0043     int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
0044     unsigned char *base;
0045     u16 out = cpu_to_le16(0);
0046     int r = 0;
0047
0048     memset(&args, 0, sizeof(args));
0049
0050     mutex_lock(&chan->mutex);
0051     mutex_lock(&rdev->mode_info.atom_context->scratch_mutex);
0052
0053     base = (unsigned char *)rdev->mode_info.atom_context->scratch;
0054
0055     if (flags & HW_I2C_WRITE) {
0056         if (num > ATOM_MAX_HW_I2C_WRITE) {
0057             DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
0058             r = -EINVAL;
0059             goto done;
0060         }
0061         if (buf == NULL)
0062             args.ucRegIndex = 0;
0063         else
0064             args.ucRegIndex = buf[0];
0065         if (num)
0066             num--;
0067         if (num)
0068             memcpy(&out, &buf[1], num);
0069         args.lpI2CDataOut = cpu_to_le16(out);
0070     } else {
0071         args.ucRegIndex = 0;
0072         args.lpI2CDataOut = 0;
0073     }
0074
0075     args.ucFlag = flags;
0076     args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
0077     args.ucTransBytes = num;
0078     args.ucSlaveAddr = slave_addr << 1;
0079     args.ucLineNumber = chan->rec.i2c_id;
0080
0081     atom_execute_table_scratch_unlocked(rdev->mode_info.atom_context, index, (uint32_t *)&args);
0082
0083     /* error */
0084     if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
0085         DRM_DEBUG_KMS("hw_i2c error\n");
0086         r = -EIO;
0087         goto done;
0088     }
0089
0090     if (!(flags & HW_I2C_WRITE))
0091         radeon_atom_copy_swap(buf, base, num, false);
0092
0093 done:
0094     mutex_unlock(&rdev->mode_info.atom_context->scratch_mutex);
0095     mutex_unlock(&chan->mutex);
0096
0097     return r;
0098 }
0099
0100 int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
0101                 struct i2c_msg *msgs, int num)
0102 {
0103     struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
0104     struct i2c_msg *p;
0105     int i, remaining, current_count, buffer_offset, max_bytes, ret;
0106     u8 flags;
0107
0108     /* check for bus probe */
0109     p = &msgs[0];
0110     if ((num == 1) && (p->len == 0)) {
0111         ret = radeon_process_i2c_ch(i2c,
0112                         p->addr, HW_I2C_WRITE,
0113                         NULL, 0);
0114         if (ret)
0115             return ret;
0116         else
0117             return num;
0118     }
0119
0120     for (i = 0; i < num; i++) {
0121         p = &msgs[i];
0122         remaining = p->len;
0123         buffer_offset = 0;
0124         /* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
0125         if (p->flags & I2C_M_RD) {
0126             max_bytes = ATOM_MAX_HW_I2C_READ;
0127             flags = HW_I2C_READ;
0128         } else {
0129             max_bytes = ATOM_MAX_HW_I2C_WRITE;
0130             flags = HW_I2C_WRITE;
0131         }
0132         while (remaining) {
0133             if (remaining > max_bytes)
0134                 current_count = max_bytes;
0135             else
0136                 current_count = remaining;
0137             ret = radeon_process_i2c_ch(i2c,
0138                             p->addr, flags,
0139                             &p->buf[buffer_offset], current_count);
0140             if (ret)
0141                 return ret;
0142             remaining -= current_count;
0143             buffer_offset += current_count;
0144         }
0145     }
0146
0147     return num;
0148 }
0149
0150 u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
0151 {
0152     return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
0153 }
0154