text: /*
   * Copyright 2011 Advanced Micro Devices, Inc.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
   * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   *
   * Authors: Alex Deucher
   *
   */
  #include "drmP.h"
  #include "radeon_drm.h"
  #include "radeon.h"
  #include "atom.h"
  
  #define TARGET_HW_I2C_CLOCK 50
  
  /* these are a limitation of ProcessI2cChannelTransaction not the hw */
  #define ATOM_MAX_HW_I2C_WRITE 2
  #define ATOM_MAX_HW_I2C_READ  255
  
  static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
  				 u8 slave_addr, u8 flags,
  				 u8 *buf, u8 num)
  {
  	struct drm_device *dev = chan->dev;
  	struct radeon_device *rdev = dev->dev_private;
  	PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
  	int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
  	unsigned char *base;
  	u16 out;
  
  	memset(&args, 0, sizeof(args));
  
  	base = (unsigned char *)rdev->mode_info.atom_context->scratch;
  
  	if (flags & HW_I2C_WRITE) {
  		if (num > ATOM_MAX_HW_I2C_WRITE) {
  			DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 2)\n", num);
  			return -EINVAL;
  		}
  		memcpy(&out, buf, num);
  		args.lpI2CDataOut = cpu_to_le16(out);
  	} else {
  		if (num > ATOM_MAX_HW_I2C_READ) {
  			DRM_ERROR("hw i2c: tried to read too many bytes (%d vs 255)\n", num);
  			return -EINVAL;
  		}
  	}
  
  	args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
  	args.ucRegIndex = 0;
  	args.ucTransBytes = num;
  	args.ucSlaveAddr = slave_addr << 1;
  	args.ucLineNumber = chan->rec.i2c_id;
  
  	atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
  
  	/* error */
  	if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
  		DRM_DEBUG_KMS("hw_i2c error\n");
  		return -EIO;
  	}
  
  	if (!(flags & HW_I2C_WRITE))
  		memcpy(buf, base, num);
  
  	return 0;
  }
  
  int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
  			    struct i2c_msg *msgs, int num)
  {
  	struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
  	struct i2c_msg *p;
  	int i, remaining, current_count, buffer_offset, max_bytes, ret;
  	u8 buf = 0, flags;
  
  	/* check for bus probe */
  	p = &msgs[0];
  	if ((num == 1) && (p->len == 0)) {
  		ret = radeon_process_i2c_ch(i2c,
  					    p->addr, HW_I2C_WRITE,
  					    &buf, 1);
  		if (ret)
  			return ret;
  		else
  			return num;
  	}
  
  	for (i = 0; i < num; i++) {
  		p = &msgs[i];
  		remaining = p->len;
  		buffer_offset = 0;
  		/* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
  		if (p->flags & I2C_M_RD) {
  			max_bytes = ATOM_MAX_HW_I2C_READ;
  			flags = HW_I2C_READ;
  		} else {
  			max_bytes = ATOM_MAX_HW_I2C_WRITE;
  			flags = HW_I2C_WRITE;
  		}
  		while (remaining) {
  			if (remaining > max_bytes)
  				current_count = max_bytes;
  			else
  				current_count = remaining;
  			ret = radeon_process_i2c_ch(i2c,
  						    p->addr, flags,
  						    &p->buf[buffer_offset], current_count);
  			if (ret)
  				return ret;
  			remaining -= current_count;
  			buffer_offset += current_count;
  		}
  	}
  
  	return num;
  }
  
  u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
  {
  	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
  }
  
  